Structural and nutritional differences between climbers and their supporting trees in a montane rainforest in South-Ecuador

Dissertation Thesis

Department of Systematic Botany and Ecology, University of Ulm

Dissertation zur Erlangung des Doktorgrades Dr. rer. nat an der Fakultät für Naturwissenschaften der Universität Ulm

2004 Dipl.-Biol. Jörg Salzer

Amtierender Dekan: Prof. Dr. R. J. Behm

1. Gutachter: Prof. Dr. Marian Kazda 2. Gutachter: Prof. Dr. Elisabeth Kalko

Vorgelegt am 01.10.2003 Tag der Promotion: 05.02.2004

CONTENTS

Acknowledgments IV Summary V Zusammenfassung VII Resumen IX

1. Introduction 1

2. Material and Methods 10

2.1. Geographical location of the research area 10 2.2. Climatic conditions 11 2.3. Geology, geomorphology and soils 12 2.4. Vegetation 13 2.5. The investigation plots 15 2.5.1. Soil properties and vegetation types 16 2.6. Sampling procedure and processing of the plant material 20 2.6.1. Measuring leaf area index (LAI) and canopy gap fraction (DIFN) 21

2.6.2. Measuring relative photon flux density (PFDrel) 22 2.6.3. Calculation of leaf area (LA) and leaf mass per unit area (LMA) 23 2.6.4. Kjeldahl digestion 24 2.6.5. Photometry of phosphorus 24 2.6.6. Atomic absorption spectrometry 25 2.6.7. Measurements of carbon content 25 2.7. Statistical interpretation 26 2.7.1. Description of the investigation plots 26 2.7.2. Control for associations between the two growth forms 26 2.7.3. Testing the differences between the two growth forms 26 2.7.4. Testing the differences between the investigation plots 27 2.7.5. Testing the influence of external factors on the plants 28 2.7.6. Grouping of all variables in a principal components analysis 28

3. Results 29

3.1. Environmental conditions on the investigated plots 29 3.2. Sampled specimens and the host/climber-relationship 34 3.2.1. Plant lists 34 3.2.2. Plant distribution among the plots 36 3.2.3. Associations between the two growth forms 37

3.3. The differences in structural and nutritional parameters 40 3.3.1. Differences between the growth forms 40 3.3.2. Differences between the investigated plots 43 3.3.3. Leaf parameter values of the investigated genera 49 3.4. Leaf parameters of the investigated genera 63 3.5. Synthesis of leaf parameters 69 3.5.1. Factor loadings of the PCA 69 3.5.2. Factor loadings according to the genera 71 3.6. Comparison of young and mature leaves 76 3.6.1. Collected leaf samples 76

3.6.2. Differences in LMA, Nmass and Narea 77

4. Discussion 80

4.1. Plot selection 80 4.2. Associations between climbers and host plants 81 4.3. Differences in leaf structure and nutrient allocation 83 4.3.1. Reduction in leaf mass per unit area in the climbers 83 4.3.2. Leaf structure on different plots under changing light regimes 85 4.3.3. Nitrogen allocation and its role in photosynthesis 87 4.3.4. The other nutrients 93 4.3.5. The role of Aluminium 95 4.3.6. Classification derived by PCA 97 4.4. Comparison of young and mature leaves 98 4.5. Conclusions 102

5. Literature 104

Appendices A1 Appendix 1: Environmental conditions at the sample pairs A1 Appendix 2: Soil-pH and content of exchangeable element on the plots A3 Appendix 3: Complete dataset of all collected climber species A4 Appendix 4: Complete dataset of all collected supporter species A6 Appendix 5: Mature and young leaves dataset A8 Appendix 6: Mean leaf structure parameters A9 Appendix 7: Mean leaf element contents A9 Appendix 8: Mean leaf structure parameters among all plots A10 Appendix 9: Mean leaf element contents among all plots A11

Acknowledgements IV

ACKNOWLEDGEMENTS

I want to express my acknowledgements to all who helped me with my work during the past four years.

Firstly, I want to thank Prof. Dr. Marian Kazda for giving me the opportunity to conduct my studies in several tropical countries, for guidance in every critical phase, and for the free and trusty atmosphere he provided me in the Department of Systematic Botany and Ecology. Not to forget his financial support during the whole time.

Secondly, I want to express my thanks to the co-referent Prof. Dr. Elisabeth Kalko, as she showed so much interest in my work.

Without Prof. Dr. Sigrid Liede from the University of Bayreuth this work would not have been possible. She asked me to help one of her PhD students in Ecuador and gave me also the possibility to perform my own scientific program there. The study was included in and partly financed by the DFG projects LI 496/11-1 and LI 496/11-2.

Research permit was given by the Instituto Ecuadoriano Forestal de Areas Naturales y Vida Silvestre (INEFAN), and logistic help came from the Fundación Cinetífica San Francisco (FCSF). Scientific counterpart in Ecuador was Ing. Zhoffre Aguirre.

I also want to thank Patricia Brtnik for translating the summary into spanish, Graciela Hinze for her final reviews on the “resumen”, Dr. Iris Schmid, Philipp von Wrangell, Norbert Gäng, Kordula Heinen and Gregoire Hummel for their ideas during the past years, Christel Necker for her outstanding help in the laboratory, Steffen Matezki for determination of most samples, and a long list of other people for their friendship and support – hopefully they all know that they are mentioned.

Special thanks go out to Rita Schneider. She gave me not only substantial comments on the manuscript, but also amounts of motivation and a place of peacefulness for my mind in hard phases during the past months.

Finally, I want to mention my parents. They enabled me always to follow my way and gave me all the support I needed so much. I just hope that my mother can see how everything now has come to a great end. Summary V

SUMMARY

Climbing plants, like lianas, vines or root climbers, can be the dominating growth form on several sites not only in tropical forests but also in other climatic zones. Climbers from a wide range of plant families can be found especially on forest edges and treefall gaps. The uneven distribution of this growth form was well investigated in the past years and different reasons for that patchiness, like light demand, support quality and nutrient or water availability were mentioned but not fully understood. Further research upon the relationships between external parameters and climber abundance is necessary as different types of mostly negative effects on the host trees were reported in many studies. Knowledge about the climbers ecophysiology is mainly limited on transpiration and water transport, but other physiological mechanisms that also determine the competitiveness of a climbing plant and thereby its abundance are still poorly understood. The climbers fast growth requires fast adaptability to changes in their surrounding conditions, such as effective biochemical mechanisms within the plant, combined with low growth-cost and high nutrient content. Former studies already indicated a good assignment of nitrogen towards light harvesting under shade by low leaf mass per unit area (LMA) in the leaves of climbers, accompanied by high leaf nitrogen contents. Aim of this study was to improve the knowledge about the mechanisms that lead to different patterns in climber abundance. Therefore basic data in high resolution were inquired about the nutritional status of climber leaves compared with their supporting hosts along different environmental conditions.

The study was performed in a primary montane rainforest in South-Ecuador along an altitudinal gradient between 1930 m a.s.l. and 2700 m a.s.l., covering a wide range of different forest types. On each of the 8 investigation plots 10 pairs of climbers and supporting host plants were selected. Stand characteristics were investigated by measuring LAI, DIFN and PFDrel below each sample pair and directly above them. The single plots distinguished well in their crown closure and light availability, giving so the possibility to achieve high resolution data about the different reactions of climbers and their supporting trees towards changing conditions. Retarded nutrient turn-over in the soils of the undisturbed plots on the investigation area, a varied mosaic of parent materials, and therefore extremely patchy nutrient availability conditions can explain the uneven abundance of climbers in the ECSF forest with its huge species and structural diversity. Host tree preferences by climbers were tested but were not evident and did so not Summary VI influence the further evaluation. Leaf samples from both growth forms were collected pair wise and analysed for structural factors (LA, LMA, C, Carea) and element contents (Nmass,

Narea, P, K, Ca, MG, Mn, Al).

Results showed that investment in supporting tissues on leaf level was lower by the climbers than that by their hosts. Climbers built smaller leaves with lower specific leaf mass (LMA). The morphological structures were better adapted to the prevailing light conditions than within the self supporting vegetation. Very economic allocation of nutrients was expressed on leaf area basis (Narea) by irradiance input optimised nitrogen contents. Variations in LMA and Narea values along the light gradient were remarkably lower within the climbers. With less investment per leaf area the climbers can achieve comparable carbon gain as their hosts, which was confirmed by photosynthesis measurements in another ecosystem. The efficient use of nutrient resources was also evident for phosphorus and potassium, which enables the climbers not only to allocate nutrients towards their shoot growth but also fast responses toward changes in their environment. Several variables like e.g. PFDrel, LMA and Narea were combined to new factors in a principal components analysis. The percentage of explained variance by the factors and the factor loadings of the single parameters were higher within the climbers, and accordingly reflected their higher degree of adaptation. Comparing freshly emerged with mature leaves, different allocation patterns of nitrogen between trees and climbers confirmed the results. The climbers leaves were characterised by generally higher leaf nitrogen concentrations than those of their supporters, but the evidence of a delayed nitrogen flush into developing leaves might reduce herbivory pressure on the soft climber leaves. Within the self supporting vegetation some Al-accumulators from the family of Melastomataceae were found. Low numbers of large lianas might be a result of less abilities to handle the acid soil conditions that lead to high concentrations of toxic mobile aluminium (Al3+).

The combination of several physiological and morphological traits in their leaves enables the climbers to exploit sites that vary broadly in light and crown closure. But the good adaptability of climbing plants is strongly demanding a sufficient nutrient supply, which explains their high abundance on sites with increased nutrient availability. Zusammenfassung VII

ZUSAMMENFASSUNG

In den vielen Klimazonen dieser Erde, aber vor allem in den Tropen stellen Kletterpflan- zen die lokal dominierende Wuchsform dar. Verschiedene Typen von Kletterpflanzen aus ganz unterschiedlichen Familien finden sich in hoher Abundanz an Waldrändern oder - lichtungen. Als Gründe für die ungleichmäßigen Verteilungsmuster der Kletterpflanzen wurden hoher Lichtbedarf, Wasser- und Nährstoffverfügbarkeit sowie das Vorkommen und die Qualität von Trägerstrukturen genannt, jedoch fehlt bislang ein umfassendes Ver- ständnis für die Bedeutung dieser Faktoren. Weiterführende Untersuchungen auf diesem Gebiet sind nötig, da der Einfluss der Kletterpflanzen auf die Trägerpflanzen in den meis- ten Fällen stark negativ zu beurteilen ist. Ein Großteil der bisherigen Arbeiten über die Ö- kophysiologie von Kletterpflanzen behandelt die Transpiration und den Saftfluss. Noch mangelt es an Wissen darüber, inwiefern weitere physiologische Mechanismen die Kon- kurrenzkraft und damit die Abundanz dieser Wuchsform beeinflussen. Kletterpflanzen müs- sen aufgrund ihres schnellen Wachstums in der Lage sein sich an rasch wechselnde Um- gebungsbedingungen anzupassen, was effektive biochemische Mechanismen innerhalb der Pflanze erfordert. Die hierzu nötigen hohen Nährstoffgehalte sollten dennoch mit ge- ringen Wuchskosten einhergehen. Dies wird durch eine geringe flächenbezogene Blatt- masse (LMA) bei gleichzeitig hohem Stickstoffgehalt ermöglicht Ziel der vorliegenden Ar- beit war es, die grundlegenden Mechanismen die zu den beschriebenen Verteilungsmus- tern führen besser zu verstehen. Hochauflösende Daten entlang sich verändernder Um- gebungsparameter über die Nährstoffgehalte in Blättern von Kletterpflanzen und ihren Trägern wurden hierzu erfasst und miteinander verglichen.

Die Studie wurde in einem Bergregenwald in Südecuador durchgeführt. Entlang eines Bergrückens zwischen 1930 und 2700 m ü. NN. wurden 8 Plots in verschiedenen Vegeta- tionstypen eingerichtet. Jeweils 10 Träger-Kletterpflanze-Paare wurden markiert und ihre

Umgebungsbedingungen mit Hilfe von LAI, DIFN und PFDrel Messungen - zum einen unter dem jeweiligen Pflanzenpaar, zum anderen unmittelbar über dem zu erntenden Zweig- paar – bestimmt. Aufgrund der deutlichen Unterschiede die sich hierbei zwischen den Flächen abzeichneten, war es möglich hochauflösende Informationen über die Reaktio- nen beider Wuchsformen auf sich verändernde Umgebungsbedingungen zu erhalten. Das ungleichmäßige Auftreten von Kletterpflanzen im Untersuchungsgebiet lässt sich auf eine beschränkte Nährstoffmobilität in den Böden, einem Mosaik an Ausgangsgesteinen und somit auf eine sehr ungleichmäßigen Nährstoffverfügbarkeit zurückführen. Präferen- Zusammenfassung VIII zen einzelner Kletterpflanzengattungen für spezielle Trägerbäume wurden getestet, konn- ten ausgeschlossen werden und beeinflussten somit die weitere Auswertung nicht. Nach paarweiser Ernte wurden die Blätter beider Wuchsformen bezüglich ihrer strukturellen

Merkmale (LA, LMA, C, Carea) und ihrer Nährstoffgehalte (Nmass, Narea, P, K, Ca, MG, Mn, Al) untersucht.

Die Kletterpflanzen zeigten deutlich geringere Investitionen in die Stützgewebe ihrer Blät- ter mit geringerer LMA und LA (Blattfläche) als die Blättern der Trägerbäume. Die morpho- logische Anpassung der Blätter an die Umgebungsbedingungen war innerhalb der Klet- terpflanzen deutlicher als bei ihren Trägern. Hohe massenbezogene Blattstickstoffgehalte ermöglichen hohe Wuchsraten bei den Kletterpflanzen. Zudem war eine ökonomische Verteilung von Nährstoffen deutlich anhand des niedrigen flächenbezogenen Stickstoff- gehaltes (Narea) zu erkennen. Offensichtlich war Narea in den Blättern der Kletterpflanzen besser an die jeweilige Lichtbedingung angepasst. Trotz geringerer Investition je Blattflä- che können die Kletterpflanzen somit vergleichbare Kohlenstoffgewinne wie ihre Träger erreichen, was durch Gaswechselmessungen in einem anderen Ökosystem bestätigt wurde. Auch Phosphor und Kalium werden von den Kletterpflanzen sehr effizient für die Anpassung an die jeweiligen Wuchsbedingungen genutzt. Mit Hilfe einer PCA wurden mehrere Einzelvariablen, wie z.B. PFDrel, LMA und Narea zu neuen Faktoren zusammenge- führt. Höherer Anteil an erklärter Varianz und höhere Faktorenladungen bestätigten die bessere Anpassungsfähigkeit von Kletterpflanzen. Auch ein Vergleich von voll ausgebilde- ten und jungen Blättern beider Wuchsformen ergab ökonomisch sinnvolle Ergebnisse. Der Blattstickstoffgehalt der Kletterpflanzen ist zwar generell hoch, jedoch schützt ein verzöger- tes Einlagern in die sich noch entfaltenden weichen Blätter diese vermutlich vor Herbivo- rie.

Die Kombination spezieller physiologischer und morphologischer Blatteigenschaften er- laubt es den Kletterpflanzen Flächen zu besiedeln, welche sowohl im Lichtangebot als auch anderer Ressourcen stark variieren. Die hohe Anpassungsfähigkeit bedingt allerdings auch eine ausreichende Nährstoffversorgung. Dies wiederum kann die hohe Abundanz bzw. das Fehlen von Kletterpflanzen auf einigen Flächen erklären. Resumen IX

RESUMEN

En muchas zonas climáticas, especialmente en los tropicos, las plantas trepadadoras, como las lianas, son la vegetación dominante. Varios tipos de las plantas trepadoras de diferentes familias se encuentran con alta abundancia en los límites del bosque o en los claros del bosque. Como razón es posibles para la distribución irregular se discuten la alta necesidad de luz, la existencia de agua y nutrición tanto como la calidad de las plantas hospedantes, aunque falta todavía entender por completo el significado de todo los factores involucrados. Investigaciones completamentarias en este campo son necesarias, ya que el efecto y la influencia de las plantas trepadoras sobre la planta hospedante en la mayoría de los casos son negativos. La mayoría de las investigaciones sobre la ecophysiología de las plantas escaladores tratan de la transpiración y de la circulación de liquidos. Todavía existe un déficit en el conocimiento de cómo otros mecanismos physiológicos influyen la competición y así la abundancia de estas plantas. Plantas trepadoras, por su crecimiento veloz, necesitan acostrumbarse rápidamente a cambios de las condiciones de su ambiente. Esto requiere mecanismos bioquímicos efectivos dentro de la planta. Por otro lado la alta necesidad nutritiva requerida debería estar combinada con costos bajos en el crecimiento. Esto se logro mediante una baja masa de hojas por unidad (LMA) y a mismo tiempo altas concentraciones de nitrógeno. La finalidad de esta investigación ha sido mejorar el conocimiento de los mecanismos conducen al patrón de distribución mencionado. Se han recolectados datos básicos de alta resolución sobre el estado nutritivo de las plantas trepadoras en comparación con el de sus plantas hospedantes, en diferentes condiciones ambientales.

El sitio de la investigación fué un bosque tropical montañoso en el Sur de Ecuador. Por la cuesta de la montaña, entre 1930 y 2700 metros de altura sobre el nivel del mar, fueron instalados 8 plots en diferentes tipos de vegetación. En cada plot fueren seleccionadas 10 parejas de plantas hospedantes – plantas escaladoras y se investigaron las características del lugar por mediciones de sus LAI, DIFN y PFDrel por abajo y por arriba de las plantas. Los diferentes plots se distinguieron claramente en quanta a densidad de vegetación y luz, dando asi datos resultantes de alta resolución sobre las diferentes reacciones de las plantas trepadoras y sus hospedantes en condiciones cambiantes. La abundancia irregular de las plantas escaladores en el área del estudio se explica por la mobilidad limitada de la nutrición de los suelos, un mosaico de material parental y así resulta una disponibilidad irregular de nutritivos. Preferencias Resumen X por plantas hospedantes han sido investigados, resultaron no evidentes y así no hay una influencia en las siguentes evaluaciones. Pruebas de hojas de las dos diferentes plantas han sido recolectadas en parejas y analizadas por factores estructurales (LA, LMA, C,

Carea ) y sus contenidos (Nmass, Narea, P, K, Ca, MG, Mn, Al).

Los resultados demuestran que la investitión en tejido de apoyo a nivel de hojas de las plantas trepadoras ha sido mucho menos que la de las hospedantes. Las trepadoras tienen hojas más pequeñas con menos masa específica de hojas (LMA). Las adaptaciones morphologicas de las hojas a las condiciones ambientales han sido mas desarolladas en las plantas escaladores que en las plantas hospedantes. Altas concentraciones de nitrógeno en relación con la masa facilitan el alto crecimiento de las plantas trepadoras. Además se pudo ver una distribución económica de los nutrientes por la concentración baja de nitrógeno por área (Narea). Parece que Narea esta mejor adaptada a las condiciones de luz. Por eso las plantas trepadoras alcanzan con una inversión más baja por área de hoja una ganancia de carbono comparable con la de las plantas hospedantes, como se probó con mediciones de cambios de gases en otros ecosistemas. También el fósforo y el potasio son aprovechados eficientemente por las trepadoras para una adaptación a los cambios del ambiente. Se unieron diferentes variables como por ejemplo PFDrel LMA y Narea a un factor nuevo a través de una PCA. Un porcentaje más alto de las variables mencionados y una carga más alta de los factores confírman la mejor adaptación de las plantas trepadoras. La comparación de hojas maduras y hojas jovenes de las dos plantas confirmó los resultados de la efíciencia. La concentración de nitrógeno en las hojas de las plantas trepadoras en general es más alta pero la evidencía de la transición atrazado del nitrógeno por las hojas jovenes las proteje de la herbivoría.

La combinación de las characterísticas physiologícas y morphológicas especiales de las hojas permiten a las plantas trepadoras colonizar áreas con variaciones de condiciones ambientales. La alta capacidad de adaptación les ayuda obtener una nutrición suficiente. Esto puede explicar la abundacia alta y la falta de las plantas trepadoras en algunos lugares. Introduction 1

1. INTRODUCTION

General overview

Tropical rainforests are the most diverse ecosystems on this planet (Mueller-Dombois & Ellenberg 1974), only comparable with oceanic coral reefs. They host minimum 50 % of all expected species, although covering only 6 to 7 % of the continental area (Erwin 1982, Linsenmair 1990, May 1996). Innumerable work about the flora and fauna of these fascinating ecosystems has been published in the last decades. It seems astonishing that one dominating group of plants was nearly neglected in the main, the climbers. Still lianas are the most undercollected of any major plant group (Gentry 1991) – although already in the 19th century Darwin (1897) described the exceptionalities of climbing plants. In the past 25 years, with the recognition of their importance in forest ecology, climber-related research began slowly to increase (Schnitzer & Bongers 2002). In 1991 a collection of articles about vines was published by Putz and Mooney in their “The Biology of Vines”, which contains still some of the most important work done on climbing plants. According to Putz (1985) nearly one half of the vascular plant families contain climbing species. They can be found in the Gymnosperms, as climbing bamboos in the Poaceae, and in a great variety of many dicotyledonous families. Prosperi & Caballé (2001) gave detailed overview about distribution of climbers within the most important families. Access to the sometimes extremely tall plants, growing in the outer canopy, is very difficult without using complicated canopy access systems. So studies about and collection of climbers from the tree crowns are rare. It is hard to define climber individuals and their small stem diameters are frequently excluded in many studies as stated by Muthuramkumar & Parthasarathy (2001). As a result of these problems already Jacobs (1976) pointed out the lack of knowledge about the ecology of these plant form. This knowledge began to increase in the last years, but is still not comparable with that on self supporting vegetation like trees. The growth form climber is widespread over nearly all climatic zones, but the distribution of climbing plants is geographically uneven. They can be found in the arid Mediterranean’s (Rundell & Franklin 1991) as well as in the mountainous regions of the alps, but especially woody lianas reach their highest abundance and diversity in the forests of the tropics (Gentry 1991). Thereby lianas are the most important physiognomic feature to differentiate tropical from temperate forests (Croat 1987). Former studies Introduction 2 describe liana infestation rates of 40 – 50 % on rainforest trees (Montgomery & Sunquist 1978, Putz 1984, Putz & Chai 1987) and about a fifth of the upright understorey plants of neotropical forests are juvenile lianas (Rollet 1969). Several young shrub-type plants found in the understorey become lianas later in their life cycle (Jacobs 1976). Herbaceous species were mostly neglected in investigations about climbers. The dominance of climbers in forests gets even more obvious when adding these herbaceous to the woody liana types. Gentry (1985) distinguishes between four different climber types, concerning their ecology and morphology: (i) Woody, thick stemmed climbers that begin their life as terrestrial seedlings are called lianas. They have the ability to reach the crowns of large mature trees. (ii) Thin-stemmed, herbaceous or subwoody climbers that also grow as seedlings from the ground are called vines. They are mostly found on disturbed sites and forest edges. (iii) Woody hemiepiphytes, including stranglers, begin their life as epiphitic seedlings that reach later the ground with their roots. In some cases they start as terrestrial climbers, losing their contact to the ground later after sending out a system of adventitious roots. (iv) Herbaceous epiphytes or hemiepiphytes include all non-woody climbers that grow appressed to tree trunks, mostly by using adventitious roots. They can keep contact to the ground or maybe loose it, and can also be classified as root climbers.

The following study of a montane forest in Ecuador is focused on the first two types of climbers. Lianas were not very abundant on the investigated sites, most collected samples were subwoody vines.

One well investigated topic about the biology of climbers is their distribution within different forest structures. Substantial work was published from Indo-Malaya (Putz & Chai 1987, Nicholson 1965, Padaki & Parthasarathy 2000, Muthuramkumar & Parthasarathy 2001) as well as from some African forest systems (Lowe & Walker 1977, Balfour & Bond 1993, Eilu 2000, Caballé & Martin 2001) and from the neotropics (Gentry & Dodson 1987, Uhl et al. 1988, Dewalt et al. 2000, Nabe-Nielsen 2001). All these investigations describe an uneven distribution of climbers among different forest types. Same results were reported by Rollet (1971, ex. Hegarty & Caballé 1991) for the stems of vines in some locations during a study in Venezuela. The climbers showed a Poisson-type clumped Introduction 3 distribution, being absent from some sampling plots while having high abundances on others. Although most climbers are known to be highly light demanding (Putz 1984, Castellanos 1991), there are also same shade-tolerant species (Grubb et al. 1963), mostly from the group of the tiny and thin stemmed vines (Chalmers & Turner 1994). In most cases they are not distributed randomly on their potential host trees (Campbell & Newberry 1993). Often climbers build large curtains along forest edges and in treefall gaps, where closely-spaced, small-diameter supporters like young trees or shrubs are available (Peñalosa 1983, Uhl et al. 1988). Support of this kind was mostly found to control the liana access to the forest canopy (Putz 1984, Hara 1987, Nabe- Nielsen 2001), sometimes even more than nutrient content in the soil (Balfour & Bond 1993). Investigations about the relationship between climber distribution and nutrient supply were also carried out for example by Van Daalen (1984), Donald et al. (1987) or Hättenschwiler (2002) and confirmed this finding. All these results indicate that the distribution and abundance of climbers is often determined by structural factors, in particular the architecture of the host trees. Hegarty & Caballé (1991) pointed out that light has also to be considered as one main factor that determines climber distribution, although again supporting structures seemed to be more important. The climbing mechanism itself determines in part which trees can be suitable supporters for climbing plants (Peñalosa 1982 , Putz & Holbrook 1991). According to Chalmers & Turner (1994) four main types of climbing mechanisms can be found: (i) Tendril climbers with modified leaves, inflorescences or stipules. The tendrils are used to twin around the supporters and help the climber to reach height. (ii) Root climbers and adhesive tendril climbers are attached to the supporters, using for example glandular secretions. (iii) Twiners use the apical portion of their shoot, branches or petioles to twin around the supporter. Twiners seem to be the predominant climber type (Chittibabu & Parthasarathy 2001). (iv) Scramblers and hook climbers lean on their supporters, but do not become closely attached to them.

The diameter of the supporter stems plays an important role in their colonization by vines, as climbers with different climbing mechanisms are constrained to this factor (Putz 1984, Putz & Chai 1987). The infestation rate is also related to tree bark Introduction 4 characteristics, distance between the tree branches and the branch shedding frequencies (Putz 1984, Pinard & Putz 1994, Putz 1995). The branch free bole height is negatively correlated with infestation as pointed out by Campbell & Newberry (1993). Nevertheless, even trees with bark textures that should inhibit liana establishment, for example by a very loose bark that gets exchanged every few weeks, can be colonized via the crowns of neighbouring trees (Carse et al. 2000). These factors lead to an unevenly distribution of climber species among their supporters (Muthuramukar & Parthasarathy 2001). Beneath some generalists, climbers with a specialisation toward specific host trees can be expected. In Argentina Kazda & Mehltreter (2001) found a strong relationship between the climbing Smilax campestris Griseb. and the supporting shrub species Celtis tala Gill. ex Planch. In only one study by Williams-Linera (1990) a positive effect of climbers on other plants was described: With their high abundance along forest edges, climbers can play an important role in building up a buffer that protects the forest vegetation from unfavourable conditions in the adjacent gaps. As trees and climbers interrelate strongly, they build up a dense network system within the forest structure. This network often causes problems in natural forest management. Timber logging may cause significant damage to forest regeneration. When felling one single tree, its connection to other trees via the climbers causes larger canopy gaps and an increasing damage to the residual forest stands (Putz 1985, Putz 1991, Vidal et al. 1997). Climber pre-logging to improve the precision of felling was discussed controversially because of its expensiveness and unsure overall effectiveness (Fox 1968, Lowe 1978, Parren & Bongers 2001). Once a gap emerges, the survived climbers develop well (Putz 1985, Schnitzer et al. 2000, Gerwing 2001) and even small parts of climber stems can easily take root and sprout (Appanah & Putz 1984). With their high growth rate young vine seedlings have detrimental effects on tree development as Pérez-Salicrup (2001) evaluated in a cutting experiment. Climbers grow much faster than tree seedlings, accordingly their leaves can shade the submerged tree foliage (Trimble & Tryon 1974). Another impact factor was pointed out in Trimbles work, that had been carried out in the Appalachians: The climbers weight bend down the crowns of the young trees and snowfall additionally increases this problem. Siccama et al. (1976) described direct impact on trees due to increased ice damage in relation to their infestation rate. Therefore climbers can cause serious problems in timber production in temperate regions, too, where e.g. grapevines (Vitis sp. L.) or Clematis sp. L. can reach high abundances. Apart from impact on young trees, climbing plants also Introduction 5 have negative effects on adult trees. While growing, tree stems get more and more deformed and injured by tightly twining vines (Lutz 1943). Therefore Lutz (1943) postulated an inhibited downward translocation of organic solutes as sieve tubes in the trees phloem lose their conductivity. New conductive tissues built by the trees can reduce this influence, but especially the roots of seedlings often die of starvation, when the development of such new tissues is too slow. Fecundity of trees was also reported to be negatively affected by climber infestation. The manual reduction of liana load on trees in a Costa Rican deciduous forest led to an increased fruit production (Stevens 1987). Not only above ground factors affect the trees, also the roots of climbers seem to have negative influence on tree growth. In a 40-year-old abandoned field Whigham (1984) carried out a vine removal experiment. The importance of root removal showed clearly the negative effects of climbers even on trees that have grown tall enough to avoid direct physical suppression. All these results confirm the statement of Stevens (1987) that climbers can mainly be viewed as ”structural parasites”. Investigations about the ecophysiology of climbing plants in the past years were mostly focused on transpiration and water transport mechanisms. Many studies about these topics were carried out to describe the special mechanisms that occur due to the mechanical exceptionalities in this plant group. Lianas show variously shaped shoot anatomy, with different types of vessel arrangement (Caballé 1993). Climbers are generally described to have a consistent water balance, although being exposed to full sun in the tree crown (Walter & Breckle 1991). Competition for water between trees and climbers could be expectable but seems not to play an important role, as long as water is not the limiting factor on the site (Dillenburg et al. 1993, Barker & Pérez-Salicrup 2000). Extensive water transport through narrow liana stems is ensured by wide, efficient vessels in their xylem (Ewers et al. 1991, Lösch 2001). Lianas constituted for example 19 % of the total leaf area in a rainforest in Venezuela while they made up only 4.5 % of the aboveground biomass (Putz 1983). This leads to a high leaf area per conducting cross- section ratio. Thereby the important role of an effective water transport system becomes obvious. High root pressure enables a constant transport of transpiration water (Smart & Coombe 1983, Ewers et al.1989). All this is just a small view in the main results of a still ongoing research topic on climbing plants. Recent studies, for example by the workgroup of Küppers in Ecuador (Schmitt 2003), refine these general results. Schmitt (2003) described lower sap flow rates in montane forest lianas than known from lowland lianas. Compared with trees, lianas had smaller leaf conductance than their supporting trees, Introduction 6 which is contradictory to what was known yet. Plant reaction to changing water limitations was more sudden in lianas than in trees. Other ecophysiological mechanisms that can also determine climber abundance and distribution in forests, especially on disturbed sites, are still poorly understood. Aboveground competition was thought to be the major effect of climbers on their host trees (Stevens 1987, Campbell & Newberry 1993), but other studies indicate also a great role for the belowground competition. The climber roots compete strongly for soil nutrients (Whigham 1984). Dillenburg et al. (1995) identified the belowground competition for nitrogen to be intensely responsible for reduced rates of tree growth, but the climbers seem to be dependent on high nutrient amounts in the soil. Higher nutrient contents in the climber leaves compared to their supporters confirms this dependence (Kazda & Salzer 2000, Kazda & Mehltreter 2001). Climber biomass increases significantly along soil-fertility gradients (Laurance et al. 2001). Plant species distribution is often controlled by available mobilised nutrients, being expressed by the concentrations in leaves. Tanner (1977) described correlations between site quality in montane forests on Jamaica and species abundance of different foliar levels of nitrogen, phosphorus and potassium. The climbers abundance was reported to be generally higher on alluvial soils than on nutrient poor hilltops (Appanah & Putz 1984), especially when frequent river inundations leaded to enriched soil-nutrient contents (Proctor et al. 1983). Hättenschwiler (2002) reported species specific relationships between seedling growth and added nutrients from a fertilisation experiment in Panama. The three investigated liana species (Callichlamys lattifolia Bignoniaceae, Doliocarpus major and D. olivaceus Dilleniacea) showed different growth rate reactions (biomass, plant height) to fertilisation and in dependency of light availability (Hättenschwiler 2002). Increased abundance of climbers on disturbed sites could be explained by an increase in nutrient availability which is uncoupled from soil nutrient content due to higher mobilization rates (Kazda & Salzer 2000). Soil acidity is often high in tropical soils (Lüttge 1987). Under normal conditions Aluminium (Al) occurs in the soil as harmless oxides or silicates. In acid soils when pH gets below 5, Al

3+ 3+ gets solubilised into toxic Al(H2O)6 , represented as Al (Harris et al. 1996). Resulting aluminium (Al) mobilisation can lead to Al-toxicity in plants that are not adapted to these conditions. Reactions by the plants can be a reduced fine root growth, caused by injuries on the root surface (Schildknecht & Vidal 2002) or lower rates of net photosynthesis by a reduced efficiency of photosystem II (Moustakas & Ouzounidou 1994, Pereira et al. 2000). Introduction 7

Two main types of toxicity avoidance mechanisms are known, the Al-exclusion and the Al-accumulation (Cuenca et al. 1990). A more detailed description of the Al-toxicity mechanisms is given in chapter 4.3.5. A general high ratio of supported leaf weight to stem cross-section was reported by Putz (1983) and Ewers (1985). It is a result of the climbers reduced investment in supporting tissues, as they depend upon other plants for mechanical support of their plant body. This growth strategy enables to allocate more resources for reproduction and stem elongation. Thus canopy development and the build up of photosynthetic active biomass gets enhanced (Schnitzer & Bongers 2002). The structural reduction seems to be continued on leaf level as well. According to Givnish & Vermeij (1976) a low number of large thin built leaves should be expected, as this will be the most economic leaf architecture for that growth form. Climbers are reported to have lower leaf mass per unit area (LMA) than trees (Putz 1983, Castellanos et al. 1989, Cornelissen et al. 1996), especially when directly compared with their linked host (Kazda & Salzer 2000, Kazda & Mehltreter 2001). A decrease of LMA under shade has to be expected for both growth forms as a typical structural reaction to low light conditions (Jackson 1967, Chen & Klinka 1997), but might be more distinct within the climbers. Low investments in leaf structures are positively correlated with high photosynthetic gain (Poorter & de Jong 1999). Climbing plants are known to allocate proportionally larger amounts of biomass towards photosynthetically useful structures than self-supporting plants do (Suzuki 1987). To achieve highly effective gas exchange rates, the nitrogen content of the leaves principally has to be increased (Mooney et al. 1978, Ellsworth & Reich 1993, Reich et al. 1995). Growth irradiance influences the relationship between photosynthetic capacity and nitrogen content. Under higher radiation more leaf nitrogen can be expected, but the strength of this interrelation was not equal for contrasting plant types (Abrams & Mostoller 1995). Nitrogen content was reported to decrease with increasing LMA, but proportionally slower, such that area based nitrogen increases (Reich et al. 1991, Reich & Walters 1994). Different species therefore often differ in their area based photosynthetic capacity and leaf nitrogen at a given mass based nitrogen content (Evans 1989). Early successional nitrophilic vegetation typically reaches high rates of photosynthesis, which enables these plants to grow very fast (Bazzaz & Carlson 1982). As climbers also grow very fast, their leaf nitrogen content should be higher than in trees, which was reported for the vine Syngonium podophyllum from Mexico by Ackerly (1992) and confirmed e.g. for several African lowland forest species from Gabon by Introduction 8

Kazda & Salzer (2000). Area based leaf nitrogen content should be lower for the climbers as it is linked with LMA. This leads to a better assignment towards light harvesting, especially under low light conditions. Avalos & Mulkey (1999) described fast changes in the photosynthetic apparatus of the liana Stigmaphyllon lindenianum as a response to changing light conditions. Such ability allows lianas to respond quickly to canopy openings and optimise their carbon gain. Growing fast through many structures of a forest stand places a climbers shoot within a short time to various surrounding conditions. It is obviously important for climbers to be very selective with their investments towards structural components and nutrients according to the conditions their leaves face. This was proven on three differently shaded sites in Gabon (see above, Kazda & Salzer 2000). The ability to adapt selectively and very quickly to the surrounding abiotic conditions might give the climbers an economic advantage against trees, which makes them successful in competition under certain conditions. Herbivory is a common hazard plants have to deal with. Especially in the tropics with its great abundance of different leaf feeding insects and larvae, herbivory pressure is very high. Insects are known to forage mainly young leaves (see e.g. Choong et al. 1992, Choong 1996, Wright & Cannon 2001). Soft leaves with high nutrient contents, as it is typical for leaves short after budbreak (Field & Mooney 1986, Reich et al. 1991, Poni et al. 1994), are eaten more, although reported to have higher contents of soluble phenolics for defense than mature leaves (Choong 1996). With their low LMA and high nitrogen contents, (young) climber leaves generally should be a preferred diet of herbivores. Hegarty et al. (1991) reported higher amounts of defensive secondary compounds in liana leaves, compared with tree leaves. Nevertheless also different allocation patterns for nitrogen to avoid herbivory pressure might be expectable in young climber leaves. Untypical nitrogen allocation with age was found in samples from Gabon, where mass based nitrogen remained constant with leaf age, although LMA increased as expected (Kazda & Salzer, unpublished). A comparison of LMA and nitrogen between young and mature leaves of self supporting vegetation and the adjacent climbers from the montane forest of Ecuador could give some additional information about plant specific reactions to the surrounding growth conditions. Introduction 9

Aim of this study

Within the framework of this thesis, differences between climbers and their adjacent supporting vegetation were investigated pair wise. The sampling was carried out on several plots in a primary montane rainforest in the Ecuadorian Andes. Work about climbing plants in these region should support for a better understanding of the complex forests in this hotspot of diversity. This study shall give additional information to the results of other studies, that better nutrient allocation and low investments in structural tissues enable the climbers to be highly competitive against the self supporting vegetation.

The investigation deals with the following questions:

· Are there any preferences for host tree species within the sampled spectrum of climbers, which would have influence on the further data evaluation?

· Are the reported reductions of leaf mass per unit leaf area in the climbing plants also valid for this ecosystem?

· Are there differences between both growth forms in their leaf nutrient contents?

· Is the acclimatisation towards the prevailing light conditions better performed by an enhanced nutrient allocation of the climbers?

· Are there any plant specific reactions to the expected high soil acidity?

· Do young climber leaves differ from young tree leaves, and are there differences in leaf mass per unit area and nitrogen content of the two growth forms also valid for young leaves?

The sampling procedure followed mainly the proven methods from studies of our workgroup in Gabon, Madagascar, Argentina and Germany. Therefore a comparison of the Ecuador site with these totally different ecosystems was possible. The present study offered a much higher resolution concerning the changes in growth conditions for the investigated plants. Also the sample number increased, which allowed improved and new approaches for the analysis of the dataset.

Material and methods 10

2. MATERIAL AND METHODS

2.1. GEOGRAPHICAL LOCATION OF THE RESEARCH AREA

Ecuador is located in the north-west of the South American continent, bordered by the Pacific ocean, Colombia and Peru. Four main regions divide this 272045 km2 sized tropical country: The Galapagos archipelago, with its unique flora and fauna; “la costa” - the coastal region in the west; “el oriente” - a part of the Amazon basin in the east; and “la sierra” - the high mountain region of the Andes with its active volcanoes exceeding elevations of 6000 m a.s.l.. The sierra is divided into the western Cordillera Occidental and the eastern Cordillera Real by the inner Andean depression (Sauer 1971). The study site was located in the southern part of the country on the eastern slope of the Cordillera Real (3° 58’ S, 79° 06’ W). It is bordered by the 146000 ha big region of the Podocarpus National Park (Fig. 1), that is part of the provinces Loja and Zamora- Chinchipe. The investigations were carried out in the research area of the Estación Científica San Francisco (ECSF). The 1000 ha station property covers an altitudinal gradient from 1800 m a.s.l. up to more than 3100 m a.s.l., including a wide range of vegetation types.

£

ECUADOR

ECSF

3D-Map by R. Stoyan FAU Erlangen, Germany

Parque Nacional Podocarpus

Figure 1: Geographical location of the research area and the ECSF Material and methods 11

2.2. CLIMATIC CONDITIONS

Ecuador has a typical equatorial perhumid climate, but in single regions many variations can be found. The Andes as a barrier, differences in the annual radiation and episodical changes in the oceanic Humboldt-stream (e.g. the El-Niño-phenomenon) influence the local climates. In southern Ecuador some seasonal variability in the annual rainfall can be observed. For the eastern Andes Bendix & Lauer (1992) describe a maximum precipitation in June and July, caused by humid south-east winds from the Amazon basin. On the other hand, a low-level-jet stream in November leads to a short dry period that occurs in most of the years.

San Francisco, 1800m 3.98 S 79.10 W

Month

Figure 2: Climate-diagram from the San Francisco valley, Ecuador (Years 1974 – 1983); INHAMI (Maldonado 1985); Figure by Hagedorn (2001), (modified, T = temperature, N = precipitation, PLV = potential landscape evatranspiration)

The climatic conditions on the study site are in accordance with this general data. During the observation time from 1974 until 1983 the INAMHI climate station in the San Francisco valley near to the ECSF (1800 m a.s.l.) showed an annual mean temperature of 17.3°C, a relative humidity of 80 – 90 % and an average annual rainfall of 2283 mm, Material and methods 12 reaching its maximum from March to August (see Fig. 2). Especially in June and July the strong winds (up to 120 km/h) from the east bring a great amount of rainfall (up to 280 mm). The drier period, called “veranillo” by the local people, lasts from September to February, with a minimum of precipitation in November (105 mm) (Maldonado 1985).

2.3. GEOLOGY, GEOMORPHOLOGY AND SOILS

The study site belongs to the “Loja Terrane”, formed by Triassic granites and metamorphorised Palaeozoic sediments (Litherland et al. 1994). The southern region of the Cordillera Real and the adjacent northern part of Peru are described as the “Chiguinda-unit”, that is mainly built up by quartzites, metamorphic loamstones, graphitic slates and phyllites (Litherland et al. 1994). The westward continental drift of South America is still rising the Andes, which causes many earthquakes in the investigation area. Due to these tectonic activities, most of the layers have been tilted and a highly differential relief originated especially at the eastern Andean slope. Steep inclinations up to 60° are typical for the Rio San Francisco valley (Fig. 3a). Together with the huge amount of precipitation this relief leads to many landslides, even in mature forests that are undisturbed by man. After such slide impacts only the mineral parent soil remains on the surface. Soils in the investigation area were described to be distributed with high patchiness (Wilcke et al. 2001, 2002). According to Schrumpf (1999), sandstones and phyllites are the main parent materials for the soil development in the ECSF-forest. With slight differentiation in their profile, these weakly developed montane soils with visible horizons can generally be classified as Inceptisols (Schrumpf 1999), with variations along the altitudinal gradient: Soil profiles from the lower parts are mainly Dystrudepts, according to the Soil Taxonomy (Soil Survey Staff 1998). Humaquepts and Petraquepts can be distinguished at higher altitudes. Some profiles from the uppermost areas of the mountain are classified as Saprists and Epiaquepts. Low cation exchange capacities, low pH levels (2.5 – 3.5) and a decreasing N-nutrition status with increasing altitude characterised the soils on the site (Schrumpf 1999) and come along with a dominant thick organic layer of

3+ wet raw humus. Aluminium in toxic concentrations of soluble Al(H2O)6 can be expected at this low pH. Plant growth on the investigation area might also be limited by a lower rate of N-mineralisation, water logging or lacking micronutrients (Wilcke et al. 2002). Material and methods 13

2.4. VEGETATION

The flora of Ecuador belongs to the Neotropis Schmithüsen (1968). Lower altitudes should be covered with tropical rainforests, the sierra with montane rainforests that end up in the highest regions with Puna and Páramo (Schmithüsen 1976, Valencia et al. 1999). Estimations of about 20000 vascular plant species (Harling 1986) in over 2100 genera (Eliasson 1991) indicate the extraordinary species richness of this relatively small country. 30 % of the described plants seem to be endemic (Balslev 1988) and especially the southern part of Ecuador above 2000 m a.s.l. is well known to be one of the worlds hotspots of endemism (Borchsenius 1997). Madsen (1989) estimated 3000 to 4000 plant species only for the Podocarpus National Park. Figures 3a-f give some exemplary impressions about the diverse vegetation structures in the investigation area. Information about the basic vegetation zonation of the montane ECSF forest were provided by Bussmann (2001). He divided the mountain slope into three main altitudinal areas, dominated by three main plant communities. In altitudes from 1850 – 2100 m the Ocotea – Nectandra community dominates the “Montane broad- leaved forest”. Dense crown cover of 25 m tall trees from different families (e.g.: Lauraceae, Melastomataceae, Rubiaceae and others) characterises this formation. From 2100 up to about 2750 m the “Upper montane forest” (Purdiea nutans - Myrica pubescens – Myrsine andina forest) with its dominating Purdiea nutans (Cyrillaceae) establishes. On more open sites, a characteristic 1-2 m tall herb layer of large Bromeliaceae gets dominant (“Guzmania vanvolxemii community”). Above 2450 m the “subalpine elfin forest” occurs. It is comparable with the Bolivian “Yalca”, more bushland than forest, and dominated by some Clusiaceae (Clusia spp.), Cunoniaceae (Weinmannia spp.) or small Melastomataceae (Miconia spp.). First small patches of “Páramo” occur from 2650 m. Poaceae dominate, accompanied by some small Ericaceae shrubs. A real timberline does not exist in the research area, as strong winds lead to a patchiness of Páramo and Yalca, depending on wind exposition. These main forest types are accompanied by several other communities, that add to or replace them under special conditions, for example after fire (Rhynchospora loculpes community) or on very shallow soils on quartzite layers (Cladonia - Peperomia hartwegiana variety). A more detailed description of the forest formations was given by Paulsch (2001), based on structural parameters. Along the slope of the investigation area Material and methods 14 he divided the vegetation into 14 groups of different structural forest types (See also Chapter 2.5.1.). Big woody lianas reach their altitudinal limit of occurrence in the investigated montane forest (Schmitt 2003). They can only be found on large trees in the ravines of lower altitudes, but many small vines are abundant as connecting elements in the whole forest.

a) View on the lower montane forest (1900 m) b) Understorey of Mesophyll ridge forest (2150 m)

c) Young bromeliads in the understorey (2000 m) d) Small campsite on a quartzite hilltop (2230 m)

e) Forest edge of a great disturbed area f) Páramo patch on a wind exposed site (2700 m) (1950 m)

Figure 3a-f: Examples of some different vegetation forms on the ECSF research site. Material and methods 15

2.5. THE INVESTIGATION PLOTS

The investigation on ECSF was carried out in late 1999 during the short dry season. Remarkable amounts of precipitation occurred only at the end during the third week of December. Eight plots of each 20 x 20 m were established along a single track pathway called “Transecto 2” (T2), located on the north facing flank of the Rio San Francisco valley. The path went along a ridge, leading to the mountain top of the mountain “Las Antennas”. The plots were part of the structural and phenological works by Steffen Matezki, University of Bayreuth, Germany. Being positioned in an altitude between 1930 m and up to 2700 m a.s.l., the site covered a wide range of vegetation types. All plots were exposed approximately North (Fig. 4).

ECSF

l OF (1930m) l DF (2020m) l BF (2090m) l PF (2135m) T2 l KF (2230m)

l MF I (2280m) l MF II (2330m)

ÙN l PA (2700m) 1000 m

Figure 4: Investigation area (plot description: see 2.5.1.; 3D-map by R. Stoyan (pers. comm.))

The specification of the investigation plots mainly followed a former classification of forest structure formations on ECSF, given by Paulsch (personal communication). Detailed descriptions for some forest types that are comparable with the plots of this study were also given by Dziedzioch (2001).

Material and methods 16

2.5.1. SOIL PROPERTIES AND VEGETATION TYPES

Fresh soil samples from the two uppermost horizons were collected at the end of the stay in Ecuador. In two cases three layers were collected. The soil was packed in plastic bags and kept in refrigerators below 8°C, except of the time during the flight back to Europe. Contents of exchangeable elements and the soil-pH (in KCl) were quantified in the laboratories of the University of Ulm. (Complete table of investigated soil properties is given in Appendix 2) No full vegetation survey was made off the plant communities on the investigated plots as this was not necessary for the topics of this study. With increasing elevation, vegetation and especially the structure of the forest changed much. Specific information about the most remarking vegetation types will be given in the following. When possible, a plot classification according to Paulsch (2001) is additionally mentioned. Leaf area index (LAI) and gap fraction of the canopy (DIFN) was measured above the sampled plants (giving information about the crown closure) and below from ground level (for total values). Thereby a characterisation of the vegetation structure was possible. A detailed description of the methods is given under chapter 2.6.1. w OF (Anthropogenous open Forest), 1930 m a.s.l.: The mineral soil on this plot was covered by a thin layer of raw humus, mainly derived by dead fern and bamboo leaves that showed nearly no biotic turnover. pH of raw humus was 3.1, with an aluminium content of 277.5 mg kg-1. Carbon and nitrogen concentrations were 20.8 % and 1.1 %, respectively. The upper horizon of mineral soil had a slightly higher pH of 3.6, high aluminium content of 736.7 mg kg-1, and C and N concentrations of 4.5 % and 0.2 %, respectively. The plot was covered mostly by ferns as a typical indicator for the disturbance that took place few years ago, when a power line was built along the mountain slope. Bamboo Chusquea dombeyana accompanied the ferns building up an extremely dense curtain-like coverage (see Fig. 3e). Asteraceae were the most frequently collected self supporting family, but also several other shrubs and young trees within the huge fern cover hosted many different climbing species in a relatively high abundance. Nearly no big trees remained in this secondary succession area. Maximum vegetation height was therefore only about 6 m. The total LAI was 3.9, with

a gap fraction of only 8.3 % for the whole vegetation (DIFNt), while the gap fraction Material and methods 17

above the sampled leaves (DIFNa) on the other hand was very high (75.2 %), describing the different structures of the two vegetation layers very well. w DF (Dense Forest), 2020 m a.s.l.: Actually this forest type would be classified as “Primary ravine forest at lower altitude” according to Paulsch (2001). Figure 3a gives an example for such forest. The raw humus layer on the plot was only about 5-10 cm thick. pH was 2.9 and Al content was at 327.1 mg kg-1. C and N concentrations were 37.4 % and 1.5 %, respectively. The mineral soil had a slightly lower pH (2.8), Al content was also lower (266.5 mg kg- 1). Carbon concentration was at 2.7 %, nitrogen concentration at 0.1%. Here one of the most dense forest types on the mountain slope was found. Positioned on a relatively flat area in a ravine, the trees (often from the family Cecropiaceae) built up a mostly closed canopy. Some thick-stemmed woody lianas that reach the canopy top occur in this site, but as in the entire forest of the ECSF they were very rare. Instead of the big lianas, many small non-woody climbers from many different families were abundant. Seven of the 10 collected tree samples belonged to the species Miconia riveti (Melastomataceae), which gives an idea of their dominance in the understorey. Vegetation height was about 20 to 25 m. Total gap fraction was only 1 % and only 2.8 % above the collected samples. This describes the very open understorey below a dense crown closure of the big trees. Collections were made mainly from the middle stratum of the vegetation between 2 and 4 m. An undergrowth of small plants was nearly missing. Nevertheless total LAI was 6.8. w BF (Bamboo Forest), 2090 m a.s.l.: This plot was located in one of the steepest areas of the ECSF forest, reaching an inclination of nearly 40°. Compared to the DF plot, the upper soil horizon had changed much in thickness. Here the mineral soil was covered with sometimes more than 20 cm of raw material. The humus had a pH of 2.4 with an Al content of 423.0 mg kg-1. Nitrogen concentration was 1.8%, carbon was not measured as the amount of soil sample was not sufficient. Mineral soil with a pH of 2.8 had aluminium contents of 380.3 mg kg-1. Carbon and nitrogen concentration were 2.9 % and 0.2 %, respectively. Many climbing Bamboo (Chusquea dombeyana) dominated the understorey, mainly represented by a middle stratum of vegetation. Also many non-woody Material and methods 18

Asteraceae occurred on this site. An undergrowth of small plants was nearly missing, comparable to the DF plot. Trees reached approximately 12 m of maximum crown height. Crown closure above the samples was lower than on the DF plot. The understorey on the other hand was more dense, reaching plant heights between 3 to

4 m. Gap fraction dropped from only 8.1 % above the samples (DIFNa) to 3.5 % at

ground level below the samples (DIFNt) with a total LAI of 5.1. This characterises BF as a plot with still dense crown and relatively open understorey. w PF (Palmtree Forest), 2135 m a.s.l.: This plot belonged to the “Mesophyll ridge forest” type according to Paulsch (2001). It was located on a medium steep ridge. Humus layer was sometimes over 30 cm thick, with a pH of 2.6 and an Al content of 653.9 mg kg-1. The mineral soil was less acid with a pH of 3.1 and also lower in Al, with a content of 269.6 mg kg-1. Carbon and nitrogen concentrations in the mineral soil were 44.5 % and 1.8 %, respectively. Many large palms (Aracaceae, Dictyocarium lamarckianum) characterised the canopy stratum of this forest type. The maximum 12 m crown was more open than in the undisturbed plots described before. Gap fraction above the samples was 11.7 %. The understorey vegetation became denser, as light input through these gaps increased (Fig. 3b). Middle vegetation stratum had a comparable plant composition as on BF plot. The bamboo Chusquea, some Asteraceae and the genus Smilax were the main abundant climbers on this plot. Ground dwelling bromeliads (Guzmania vanvolxemii) occurred increasingly, producing a significantly denser undergrowth than it was found on the plots of lower altitude. The total LAI on PF plot was 5.1. The gap fraction remaining when measured from ground level was 3.5 %. Although it was the same on BF plot, the different magnitude of canopy closure (Gap fraction BF 8.1 %, PF 11.7 %) describes well the different vegetation structures of these two plots.

w KF (Crippled Forest), 2230 m a.s.l.: This plot was set up on a little quartzite hilltop (Fig. 3d). The layer of raw humus had a thickness of only about 2 cm. Aluminium content of the humus was extraordinarily high (1074.7 mg kg-1), pH was at 2.8. Nitrogen concentration was 1.8 %; values for carbon are missing as the amount of sampled soil was again not sufficient for measurement. The sandy mineral soil was of a bright grey colour, having a pH of 3.0 Material and methods 19

and a very low Al content (40.9 mg kg-1). Carbon and nitrogen concentrations in the mineral soil were 0.5 % and 0.1 %, respectively. Vegetation on the hilltop was extremely scleromorphic and characterised by dwarf- growth with a high load of small epiphytes on the tree branches. As tree-to-tree-

distance increased, the canopy was no more closed and DIFNa had a value of 53.7 %. Vegetation height was about 6 m with some single trees, mainly Befaria aestuans (Ericaceae), reaching up to 8 m. An undergrowth of herbaceous plants was nearly missing, probably due to the soil conditions or occasional drought situations on this exposed site. Smaller shrubs that grew in between the trees defined a sparsely developed middle stratum. Self supporting vegetation consisted of hard leaved species, mainly from the families Clusiaceae and Ericaceae. Most abundant climbers were different thin stemmed species from the Asclepiadaceae genera Asclepias and Gonioanthela. The high total gap fraction of 20.5 % and the low total LAI of only 2.5 elucidate the over all open situation of the vegetation structure on KF plot.

w MF I (Microphyll Ridge Forest I), 2280 m a.s.l.: Two comparable plots (MF I and MF II) were investigated on a ridge at 2280 m and 2330 m a.s.l.. Both plots can be classified as “Microphyll ridge forest” (Paulsch 2001). On MF I huge amounts of raw humus were build up by dead plant material from the dense undergrowth. This up to 40 cm thick humus layer had a low pH of 2.5 with an aluminium content of 450.1 mg kg-1. The carbon content was 39.8 %, nitrogen was not measured. The mineral soil had 0.2 % nitrogen, 2.7 % carbon and 105.1 mg kg-1 exchangeable aluminium at a pH of 3.0. The trees, mainly from the species Purdiaea nutans (Cyrillaceae) or some Clusiaceae species, showed dwarf growth with small and scleromorphic leaves. Most branches had a heavy load of epiphytes. Tree distance was comparable with the situation on KF plot, leading to gap fraction of 44.5 % in the canopy stratum. Many ground bromeliads (mainly Guzmania vanvolxemii), different grasses and several species of Cyclanthaceae built a dense layer of undergrowth vegetation

(DIFNt = 7 %), which was sometimes broken by single small Melastomataceae shrubs. None of the taller trees were connected by climbers. In contrast to this climbing plants were quite abundant on shrubs with Bomarea sp., Chusquea dombeyana and some Asteraceae species. Total LAI was at 4.0. Material and methods 20 w MF II (Microphill Ridge Forest II), 2330 m a.s.l.: This second MF-Plot was comparable to the first one and belongs to the same classification type as given by Paulsch (2001). The soil nearly had the same chemical properties as on MF I, with the same huge raw humus layer upon the mineral soil. Vegetation also did not differ much in composition and structure. Total LAI in this case was 4.4. The total gap fraction, measured below the dense undergrowth, was

only 7.7 %, while DIFNa between the rare trees was 57.4 %. The geomorphology of the ridge was the only obvious difference, as the slope angle was slightly lower.

w PA (Páramo-like Vegetation), 2700 m a.s.l.: Although normally Páramo is not typical for this relatively low altitude, strong winds had so much impact on the ridge vegetation, that the Microphyll Ridge Forest was replaced here by grasses and small shrubs (Fig. 3f). Due to heavy weather conditions at the end of the investigation no soil data from the PA plot are available. The highest plot in this study was located in a vegetation type that was characterised by many small scleromorphic Ericaceae shrubs and a dominating herb layer of many Poaceae. Within these self supporting plants many climbing Smilax and again the bamboo Chusquea were quite abundant. All the plants had to face a high radiation input as shading by large plants was extremely rare. Only some small palms or single bigger Ericaceae shrubs jut out of the “undergrowth”. This

resulted in a DIFNa of 92.9 %. Total LAI was low (1.9) and a total gap fraction of 30.5 % indicates that even the dominating stratum was not very dense.

2.6. SAMPLING PROCEDURE AND PROCESSING OF THE PLANT MATERIAL

On the 400 m2 area of the single plots S. Matezki (University of Bayreuth, Germany) carried out his phenology and vegetation structure investigations. Therefore no destructive sampling was possible on the plot area itself. Ten pairs of climbers and their adjacent supporting trees in a maximum reachable height of 4 m were selected along the borders of each plot. In total 80 sample pairs were marked in the understorey. Only branch pairs on which both plants had developed leaves were selected for sampling. Therefore it was ensured that growth conditions were the same within each pair. Trees with two adjacent climbers were counted twice later in the statistics – this appeared only at three samples. Material and methods 21

Leaf area index above the sample (LAIa), gap fraction of the canopy (DIFNa) and relative photon flux density (PFDrel) were measured directly above the plants prior to sampling (see also 2.6.1. and 2.6.2). Also total LAI and DIFNt were determined from ground level. The twig pairs of the samples were clipped of, packed into plastic bags and brought to the field laboratory of the ECSF immediately. There most of the specimens were determined to genus or even species. The fresh mature and, if available, young leaves were scanned separately. Young leaves were taken from 16 climbers and 29 trees samples. Leaf area was calculated from the images (see 2.6.3.). The leaf samples were pre-dried in paper bags, using the small oven of the field herbarium. Back in the laboratories of the University of Ulm, the leaves were dried to constant weight at 60°C for 48 hours. Before grinding to powder, the dry weight of the samples was used to calculate the leaf mass per unit area (LMA). The total nitrogen content of the leaves was determined after Kjeldahl digestion (see 2.6.4.). Phosphorus was photometrically measured (see 2.6.5.), while the elements aluminium, calcium, magnesium, manganese, and potassium were detected by using an atomic absorption spectrometer (AAS) (see 2.6.6.). Total carbon content of the leaves was measured after high temperature combustion with an infrared gas analysator (see also 2.6.7.).

2.6.1. MEASURING LEAF AREA INDEX (LAI) AND CANOPY GAP FRACTION (DIFN)

To estimate the leaf area index above each plant pair (LAIa), the total LAI and the canopy gap fraction (DIFN), two LAI 2000 Plant Canopy Analysers (LICOR inc., Lincoln, Nebraska, USA) were used. In comparison with e.g. hemispherical canopy photography, the LAI-2000 is known to give even more accurate data about canopy openness (Machado & Reich 1999). The LAI 2000 measures the attenuation of radiation at five angles from the zenith. An optical sensor (LAI-2050) projects an image of its nearly hemispheric view onto five detectors arranged in concentric rings (see Fig. 5). The five readings of black and white images of canopy light transmittance after passing a 490 nm filter are calculated by dividing values from above and from below the foliage. From these transmittances at the five zenith angles, the LAI 2000 calculates LAI and DIFN. One unit was used as reference (= above canopy) and was therefore placed on the open areas of the OF-plot or the KF-plot, depending which plot was measured with the other unit (= below canopy) to ensure a minimum of distance between the two sensors. In order to get a fine resolution of the data along the timescale, the automatic logging Material and methods 22 interval of the reference unit was set to 30 s. The sensor was adjusted horizontally to the sky. Measurements were carried out under overcast sky or in the evening, when direct sun did not reach the treetops any more. The measuring unit was carried to each plant pair and the sensor arm was hold horizontally above the sample branches. If sample height exceeded 2.5 m, the unit was mounted at the end of a telescopic rod to reach approximately 4 m. Three readings were taken for the estimation of LAIa and DIFNa above each sample. To measure total LAI and DIFNt, the sensor was positioned horizontally upon the ground, again three readings were taken.

Figure 5: Principles of the LAI-2000 sensorhead. The five zenith angles of the detector rings. (Figure provided from LAI-2000 Operating Manual, April 1992, LICOR inc., Lincoln, Nebraska, USA)

Using the comm.exe and c2000.exe software programs by LICOR (LICOR inc., Lincoln, Nebraska, USA) the reference- and measurement-unit data sets were joined together to calculate the LAI and DIFN values finally. Under the mountainous conditions on ECSF it was necessary to exclude the most horizontal detector ring No. 5 (61-74°zenith angle) from the calculations by applying the “mask”-function in c2000.exe.

2.6.2. MEASURING RELATIVE PHOTON FLUX DENSITY (PFDrel)

Relative photon flux density (PFDrel) was calculated with two LI-190 SZ quantum sensors (LICOR inc., Lincoln, Nebraska, USA) which were mounted together with the LAI 2000 sensors. Data were logged into the consoles of the LAI 2000 Plant Canopy Analyser. The LI-190 SZ sensor unit measures photon flux density as photosynthetic active radiation (PAR [µmol Photons s-1 m-2]) in the 400 to 700 nm waveband. A silicon photodiode with filter for an enhanced response in the visible wavelengths is thereby used as sensor. Material and methods 23

Data were collected with the LAI 2000 units during the LAI and DIFN measurements. The sensors had been orientated horizontally to the sky. One sensor was placed in the open field for reference readings, while the second one was used for the PFD measurements above the sample twigs. Corresponding reading pairs along the recorded time-scale were determined by the LICOR comm.exe and c2000.exe software programs. Dividing the two data sets led finally to PFDrel values.

2.6.3. CALCULATION OF LEAF AREA (LA) AND LEAF MASS PER UNIT AREA (LMA) After clipping the branches, they were packed in plastic bags and brought to the ECSF. The fresh leaves were scanned immediately. Leaf morphology and nutrient content is changing with leaf development (Osmond 1983, Ishida et al. 1999, Wilson et al. 2001). Therefore only mature leaves were used for the main study, but leaf age could not be estimated exactly. Old leaves with clearly visible epiphylls and/or large traces of herbivory were rejected. When a branch also carried juvenile leaves they were also collected and treated the same way as the mature leaves to determine differences between old and young leaves of both growth forms. A leaf was defined to be young, when it was obviously not ready mature in its structure and/or colour (soft light green or leathery red). Scanning was done with a Logitech Scanman II hand scanner (Logitech Corp., Fremont, USA), wield on a 12 x 45 cm glass pane under which the leaves were positioned. Using the Delta-T Scan analytical software (Delta-T Devices Inc., Cambridge, U.K.), the resulting 200 dpi black-and-white image stripes (Fig. 6) were converted to leaf area data (LA).

Figure 6: Sample image scan stripe (scaled down) of some climber leaves (here: Cissus sp., Ampelidiaceae from the BF plot, with 114.7 cm2 calculated leaf area)

Leaf area of the samples together with their dry weight permitted to calculate leaf mass per unit area (LMA [g m-2]). LMA was also the basis for further calculations of area based nutrient contents of the sampled leaves.

Material and methods 24

2.6.4. KJELDAHL DIGESTION Kjeldahl digestion according to Bollmer-Elmer (1977) was used to determine the total nitrogen content of the sampled leaves. 100 mg of dried (60°C, 48 hours) and ground leaf material was decompositioned at 400°C for 30 min with 1 Kjeltab (FOSS Tecator AB,

Hoeganas, Sweden), 10 ml H2SO4 conc. and some boiling chip granules. The solution was then distilled into 80 ml boric acid (H3BO3, 2 %) with a Kjeltec System 1026 Distilling unit (FOSS Tecator AB, Hoeganas, Sweden). A few drops of Merck mixed indicator 5 (Merck KgaA, Darmstadt, Germany) were applied for visual check of the following titration process. The distilled samples were titrated stepwise with 0.1 n HCL using a digital Metrohm pH-meter 605 serial 02 (Metrohm AG, Herisau, Switzerland). 1 ml spent HCL corresponded with a N-content of 1.4 mg in the sample.

Derived mass based nitrogen content (Nmass) was calculated to area based leaf nitrogen

(Narea) by multiplication with LMA.

2.6.5. PHOTOMETRY OF PHOSPHORUS

The dried and ground leaves were decompositioned with HNO3 (65 %) according to Kotz et al. (1972). 100 mg powder and 2.5 ml acid were put together in closed bombs and heated 2 hours under pressure for 160°C. The solution was filled up to 50 ml with bidistilled water. The PE-bottles with the final liquid samples were put in the refrigerator, where they could be stored at 6°C for several weeks. Phosphate was determined photometrically with an UV/VIS-Spectrometer 550A (Perkin- Elmer & Co GmbH, Überlingen, Germany). The spectrometer was calibrated by using several HNO3 solutions (5 %) with different defined phosphate contents, resulting in a regression factor for extinction. All samples were mixed with HNO3 (5 %) + Molybdate- Vanadate and measured after 5 minutes at 405 nm wavelength. The calculation of the phosphorus (P) content follows equation I (- v is the value of extinction, ¶ the calculated regression factor and d the amount of dry sample powder):

v × dilution(50) × ¶ ¸10 = P - content [%] (I) d × 3.06451

Material and methods 25

2.6.6. ATOMIC ABSORPTION SPECTROMETRY For the atomic absorption spectrometry the same leaf solutions were used as described for phosphate in 2.6.5.. Contents of the metal nutrients aluminium (Al), calcium (Ca), magnesium (Mg), manganese (Mn), and potassium (K) were determined with an AAS vario 6 Spectrometer with AS52 Autosampler (both: Analytik Jena AG, Jena, Germany). The AAS was controlled by computer under IBM OS/2 operating system. The single samples were transported automatically to the burner by the AS52 rotation table. Each element changes the flame colour and therefore the transmittance of light in a specific wavelength. Three extinction values were measured while a connected printer continuously recorded the calculated element contents. Each element required different settings of the spectrometer, its dilution and the ionisation-buffer:

Al: Dilution: HNO3 (0.5 %) - (1.2x) Mn: Dilution: H2O bidest - (2x) Ionisation-buffer: KCl (0.2 %) Ionisation-buffer: -

Flame: C2H2/N2O Flame: C2H2/Air Wavelength: 309.3 nm (6.0 mA) Wavelength: 279.8 nm (10.0 mA)

Ca: Dilution: H2O bidest - (11x) K: Dilution: HNO3 (0.5 %) - (21x)

Ionisation-buffer: LaCl3 (0.2 %) Ionisation-buffer: CsCl (0.1 %)

Flame: C2H2/N2O Flame: C2H2/Air Wavelength: 422.7 nm (5.0 mA) Wavelength: 766.5 nm (6.0 mA)

Mg: Dilution: HCl (0.2 %) - (11x)

Ionisation-buffer: LaCl3 (0.5 %)

Flame: C2H2/Air

Wavelength: 285.2 nm (2.0 mA)

2.6.7. MEASUREMENTS OF CARBON CONTENT Carbon (C) content of the leaves was measured with a CS-225 Carbon & Sulfur determinator (LECO Corp., St. Joseph, USA). Approximately 50 mg sample material, a spatula of Iron Chip accelerator and one of Lecocel combustion accelerator (both: LECO Corp., St. Joseph, USA) were combusted in a high frequency induction furnace. Metal rings from carbon-steel with a defined C-content were used for calibration instead Material and methods 26 of leaf samples. The produced gases were passed through a catalyst where any carbon monoxide was converted to carbon dioxide. In the carbon IR cell the carbon content of the gas was measured as CO2. The results were adjusted to sample weight and calibration factors. Finally the carbon content was displayed.

2.7. STATISTICAL INTERPRETATION

All data were sorted, calculated to same units and prepared for further statistical approaches in Microsoft Excel 97 (Microsoft Corp., Redmond, USA). The statistical analyses and graphical presentations were then performed with Statistica ’99 Edition, Kernel release 5.5A (StatSoft Inc., Tulsa, USA).

2.7.1. DESCRIPTION OF THE INVESTIGATION PLOTS

To give detailed information about the abiotic growth factors light and LAIa (leaf area index above), that determine the surrounding conditions for the investigated plant pairs, these values were displayed along the altitudinal gradient. A regression model was applied to describe correlations between altitude, LAIa and PFDrel.

2.7.2. CONTROL FOR ASSOCIATIONS BETWEEN THE TWO GROWTH FORMS A complete list of all collected plant species and additionally their distribution among the investigation plots was displayed. As interactions between the climbers and their hosts would play a major role for interpreting further tests between the both growth forms, a Chi²-test from the module Nonparametrics/Distributions was applied for the three most abundant climber genera and their host plants. A comparison between expected and observed frequencies indicates if there might be preferences for specific supporters.

2.7.3. TESTING THE DIFFERENCES BETWEEN THE TWO GROWTH FORMS To describe the differences between the two growth forms “climber” and “self supporting vegetation” the dependent t-test (matched pairs t-test) in the module Basic Statistics was chosen. As two plants were investigated on the same sample point, they were exposed to identical surrounding conditions. Instead of treating each growth form separately (like performed in the classical t-test) and analysing raw scores, the differences between the Material and methods 27 two measures (in this case the tree and its accompanied climber) are checked in each subject. The entire part of variation in the data set, that results from unequal base levels of individual subjects, is excluded by subtracting the first score (i.e. tree) from the second (i.e. climber) for each subject pair and then analysing only these paired differences. The differences between the subjects are generally normally distributed, but this is required for the subjects themselves (Kesel et al., 1999). Confidence level was set to 5 %. Same dependent t-test was applied to describe differences between young and mature leaves. Every plant was used as one corresponding sample pair. Differences in the investigated parameters LMA, Nmass and Narea between climbers and supporters were not treated pair wise, as not all collected plant pairs had young leaves on both growth forms. For this purpose t-tests for independent samples were applied.

2.7.4. TESTING THE DIFFERENCES BETWEEN THE INVESTIGATION PLOTS When comparing the differences between the single plots, an analysis of variance (ANOVA) in the Statistica module ANOVA/MANOVA was used. A Kolmogoroff-Smirnow two- sample test in the module Nonparametrics/Distributions showed that not all data were normally distributed. As the theoretical assumptions of t-tests were therefore not met, classical ANOVA is normally not useful. Median instead of mean values, within a Kruskal-Wallis-ANOVA & Median test should consequently be applied to compare differences between the plots. Based on ranks instead of means this test only requires continuous variables in ordinal scale. Man- Whitney-U-tests, based on the same terms and guidelines, should then follow to compare the nonparametric ranked data of two particular research plots. But in the given case with its huge amount of different variables to compare, this would lead to problems with multiple testing. In spite of the mentioned problems, a classical ANOVA was used first. The results were displayed in cross tables. To check the validity of results that had p-values near 0.05, single U-tests for these particular cases were run. The U-test proofed all results from the ANOVA as valid.

Material and methods 28

2.7.5. TESTING THE INFLUENCE OF THE EXTERNAL FACTORS ON THE PLANTS

Correlation between the external factors (e.g. LAIa) and the plants (e.g. N content) was tested with Pearson Product-Moment Correlation in the module Basic Statistics. Pearson correlation assumes that the two variables are measured on at least interval scales, and it determines the extent to which values of the two variables are "proportional" to each other. Proportional means linearly related; that is, the correlation is high if it can be "described" by a straight regression line. Instead of the correlation coefficient r, the coefficient of determination r2 was used. It gives a linear explanation of the relation power between the two variables, being therefore more useful to interpret the results. The linear regression models were used to describe differences between the regression lines. Variation within tested samples was quantified by the standard error of estimate.

2.7.6. GROUPING OF ALL VARIABLES IN A PRINCIPAL COMPONENTS ANALYSIS Because of the large number of tested parameters and also the high rate of their interaction, a grouping of all variables was necessary. Principal components analysis (PCA) in the module Factor Analysis was applied therefore. PCA tests for correlations between multiple variables. If two or more items correlate highly, they can be combined linearly to one new factor, as they are quite redundant. Four new factors were calculated for each growth form. Minimum criterion was an Eigenvalue above 1.00. The regression lines of the resulting factors were rotated in the normalized varimax strategy to obtain maximised factor loadings (= correlations between the respective variables and the new factors). The distribution of the factor loadings among the genera of both growth forms was finally displayed.

Results 29

3. RESULTS

The following section is divided into six main parts. The first part gives a comparison of environmental conditions on the single investigation plots. Second part is the list of all collected specimens and a testing of possible associations between single plants on genus level. Third part displays a comparison of the climbers with their supporting trees including a survey of each plot. A closer look on the relationship between the plant types and the environmental conditions follows in the fourth part, with special interest on the driving factors that determine the differences between both growth forms. In the fifth section all parameters are grouped into four factors, and their distribution among the collected genera is displayed. Finally a comparison between young and mature leaves of both growth forms is performed in the sixth part.

3.1. ENVIRONMENTAL CONDITIONS ON THE INVESTIGATED PLOTS

The work was carried out on eight investigation plots in altitudes between 1930 m a.s.l. and 2700 m a.s.l.. Vegetation structure changed massively along this gradient, and therefore also leaf area index (LAI), gap fraction (DIFN) and relative photon flux density

(PFDrel) within each sampling plot, respectively. Measurements above the collected specimens (LAIa, DIFNa, PFDrel a) reflect the extent of crown closure, whereas the total measurements from ground (LAIt, DIFNt, PFDrel t) in combination with these values mark the density of the undergrowth. A detailed description of the plot properties was already given in section 2.5.1.

Figure 7 displays these LAI changes along the altitudinal gradient. The anthropogenous disturbed plot OF was very open and had therefore nearly the same low LAIa as the

Páramo plot PA in 2700 m a.s.l.. LAIt was remarkably higher than LAIa on OF, indicating the dense undergrowth on this site. The highest LAIa values of about 5.3 were reached in the dense DF plot with its high trees and closed canopy. Here nearly no vegetation was growing below the trees, which was reflected by small differences between LAIt and LAIa.

With increasing altitude LAIa diminished to values under 1.0, which was especially obvious above 2200 m on plots with open canopy. LAIa was correlated negatively with the altitude (y = -0.007 x + 18.9, r² = 0.66, p < 0.01) when the OF plot was excluded from Results 30 the calculations, as it plays a different role with its successional status after strong human impact.

10 Mean+SD Mean-SD Mean 8 Outliers Extremes

6 DF a LAI 4 BF PF

2 MF I KF MF II OF PA 0 1930 2020 2090 2135 2230 2280 2330 2700 Altitude [m a.s.l.]

10

Mean+SD Mean-SD Mean 8 Outliers DF Extremes

6 PF t BF MF II LAI MF I 4 OF

KF PA 2

0 1930 2020 2090 2135 2230 2280 2330 2700 Altitude [m a.s.l.]

Figure 7: Leaf area index above the plant pairs (LAIa) and total leaf area index (LAIt) along the investigation plots.

With increasing canopy gap fraction above the samples (DIFNa), the relative input of solar radiation (PFDrel a) increased, too. DIFN and PFDrel showed nearly the same course on the plots along the altitudinal gradient (Fig. 8 and 9). Highest PFDrel a of nearly 100 % was measured on the PA and OF plots, while the plants from DF, BF and PF achieved low values under 10 %. DIFNa was also highest on PA and OF, and lowest on DF, BF and PF. Results 31

Relatively high DIFNa (and also PFDrel a) in combination with low DIFNt (and also PFDrel t) on KF, MF I and MF II reflect the dense understorey on these plots. For the sampled leaves the ambient conditions from above played the most important role in their recent development. In this case light is the key factor that determines leaf parameters like structure and nutrient content. Therefore most the calculations in the following chapters will mainly refer to above sample PFDrel values.

1.0 PA

0.8 OF

0.6 KF MF II a

DIFN 0.4 MF I

Mean+SD Mean-SD 0.2 Mean BF Outliers PF DF Extremes 0.0 1930 2020 2090 2135 2230 2280 2330 2700 Altitude [m a.s.l.]

1.0

Mean+SD Mean-SD Mean 0.8 Outliers Extremes

0.6 t

DIFN 0.4 PA

KF 0.2 MF II OF MF I BF DF PF 0.0 1930 2020 2090 2135 2230 2280 2330 2700 Altitude [m a.s.l.]

Figure 8: Gap fraction above the plant pairs (DIFNa) and total gap fraction (DIFNt) along the investigation plots.

Results 32

1.0

PA OF 0.8

0.6 MF II KF rel a

PFD 0.4 MF I Mean+SD Mean-SD 0.2 Mean Outliers BF PF DF Extremes 0.0 1930 2020 2090 2135 2230 2280 2330 2700 Altitude [m a.s.l.]

1.0

Mean+SD Mean-SD 0.8 Mean Outliers Extremes

0.6

rel t PA

PFD 0.4

KF 0.2 OF MF I BF DF PF MF II 0.0 1930 2020 2090 2135 2230 2280 2330 2700 Altitude [m a.s.l.]

Figure 9: Relative photon flux density above the plant pairs (PFDrel a) and total (PFDrel t) along the investigation plots.

DIFN above the samples was strongly correlated with altitude when excluding OF plot because of its special conditions. Regression for DIFNa was y = 0.001 x – 2.77 (r² = 0.76, p < 0.01). The correlation between PFDrel a and altitude was even higher. Regression showed almost exactly the same results as described before the gap fraction (y = 0.002 x – 2.95, r² = 0.84, p < 0.01).

Results 33

The relationship between LAIa and PFDrel (Figure 10) was not linear for the vegetation stand of the selected 7 plots (OF excluded!). An exponentially decreasing regression was fitted on the negative correlation between these two parameters (y = 0.195 + e(1.68-4.60x)). Proportion of explained variance was 0.96 (r=0.98).

7

6

5

4 a

LAI 3

2

1

0 0.0 0.2 0.4 0.6 0.8 1.0 PFD rel a

Figure 10: Leaf area index above the samples LAIa in correlation with the relative light input

PFDrle a , with fitted exponential regression line.

Results 34

3.2. SAMPLED SPECIMENS AND THE HOST/CLIMBER-RELATIONSHIP

3.2.1. PLANT LISTS

On the eight investigation plots a total of 83 climbers was collected (Tab. 1). They belong to 21 different species out of 13 families. One plant was not determinable, three more were determined to their family only. So at least for 80 plants the determination of their genus was possible. 30 of them were determined to species level. Most collected plants belonged to the families Alstomeriaceae (9), Asteraceae (15), Liliaceae (19) and the Poaceae (13). plants from the genera Smilax, Bomarea and Chusquea dominated.

Table 1: Complete list of all collected climber species

Id. Family Genus Species Det. Total A Alstomeriaceae Bomarea sp. Mirb. 9 B Ampelidaceae Cissus sp. Linn. 2 C Asclepiadaceae Asclepias ditasa Linn. 5 D Asclepiadaceae Gonioanthela sp. Malme 1 E Asteraceae Mikania sp. Willd. 2 F Asteraceae Mikania szyszylowiczii Hieron. 5 G Asteraceae Pentacalia sp. Cass. 7 H Asteraceae n.i. 1 I Dioscoraceae Dioscorea sp. Miq. 5 J Ericaceae Orthaea sp. Klotzsch. 1 K Liliaceae Smilax mollis Humb. & Bonpl. Ex. Willd 1 L Liliaceae Smilax sp. [Tourn.] Linn. 18 M Malpighiaceae Banisteriopsis sp. C.B. Robinson 2 N Malpighiaceae n.i. 2 O Melastomataceae Topobea sp. Aubl. 2 P Myrsinaceae Myrsine andina J.J. Pipoly 1 Q Poaceae Chusquea dombeyana Kunth. 13 R Polygonaceae Muehlenbeckia tamnifolia Meissn. 2 S Valerianaceae Valeriana clematitis H.B. & K. 1 T Valerianaceae Valeriana laurifolia H.B. & K. 2 U n.i. 1

Results 35

Table 2 lists the 80 host species that were collected (plus three of them counting twice because of their load of two climbers - one Clusia elliptica H.B & K. (Clusiaceae) and two further undetermined Melastomataceae). There was no dominating genus within the 15 sampled families, except of Clusia. Some of the families, for example Asteraceae (9), Clusiaceae (10), Ericaceae (11), Lauraceae (11) and Melastomataceae (12), were collected more often than others.

Table 2: Complete list of all collected supporter species

Id. Family Genus Species Det. Total 1 Alzateaceae Alzatea sp. Rui & Pav. 1 2 Araliaceae Schefflera sp. Forst. 3 3 Arecaceae Dictyocarium sp. H. Wendl. 1 4 Asteraceae Ageratina dendroides R.M. King & H. Robinson 6 5 Asteraceae Baccharis macrantha H.B. & K. 2 6 Asteraceae Pentacalia lanceolifolia J. Cuatrecasas 1 7 Caprifoliaceae Viburnum sp. Linn. 1 8 Clusiaceae Clusia elliptica H.B. & K. 6 9 Clusiaceae Clusia multiflora H.B. & K. 2 10 Clusiaceae Clusia sp. Linn. 2 11 Cunoniaceae Weinmannia sp. Linn. 1 12 Cyrillaceae Purdiaea nutans Planch. 4 13 Ericaceae Befaria aestuans Linn. 3 14 Ericaceae Gauteria foliolata Rafin. 2 15 Ericaceae Vaccinium floribundum H.B. & K. 2 16 Ericaceae Vaccinium sp. Linn. 2 17 Ericaceae n.i. 2 18 Gentianaceae Macrocarpea sodiroaua Gilg. 3 19 Lauraceae Persea nectandra Nees. 2 20 Lauraceae Persea sp. Mill. 3 21 Lauraceae n.i. 6 22 Melastomataceae Graffenrieda emarginata Triana. 1 23 Melastomataceae Miconia media Naud. 2 24 Melastomataceae Miconia riveti Danguy & Cherm. 1 25 Melastomataceae n.i. 8 26 Myrsinaceae Cybianthus marginatus J.J. Pipoly 1 27 Myrsinaceae Myrsine sp. Linn. 1 28 Myrtacaceae Eugenia sp. Mich. ex. Linn 2 29 Piperaceae Piper sp. Linn. 1 30 Rubiaceae n.i. 2 31 Rubiaceae Palicurea sp Roem. & Schult. 1 32 n.i. 8

Results 36

3.2.2. PLANT DISTRIBUTION AMONG THE PLOTS

Table 3 lists the distribution of the collected sample species among the investigation plots. This table only displays collected species and can therefore give no further information about total plant species diversity or abundance on the site. The following information might change with a complete survey of all species, which was not performed in this study. Nevertheless substantial information and ideas about abundance and associations between the sampled specimens is provided. As vegetation structure changed along the altitudinal gradient in the forest, distribution was obviously uneven for most plants (see Chapter 2.5.1.).

Lowest climber diversity was found in the collected material from the KF and PA plot. On both plots the genus Smilax (Id. L – Note: See Tab. 1 and Tab. 2 for the Id. codes used in the further text) played an important role. Together with its high abundance on the MF II plot, Smilax thereby concentrated mostly on more open forest structures in higher altitudes. Species from the genus Mikania (Id. E,F) were collected mainly on dark plots at lower altitudes, with only one exception on MF II. On the other hand evenly distributed species were found within the samples, too. Chusquea dombeyana (Id. Q) was found on five of the eight plots, not related to specific light inputs or altitudes. The sampled Bomarea sp. (Id. A) specimens were also collected on four plots, ranging from the dark DF plot at lower altitude, over the more open PF, to both of the MF plots at higher altitudes and with increased relative radiation input. Supporter species were more diverse than the climbers on the plots KF or PA. Obviously most supporters were unevenly distributed among the sampling plots. The family Ericaceae was mostly limited to upper altitudes. Only two plants of this family were collected on the dense plots BF and PF. Miconia riveti (Id. 24) (Melastomataceae) was, with one exception, only found on DF. Like within the climbers also some supporter species were found along a wide range of altitude and radiation. The genus Clusia (Id. 8- 10) was mainly collected on the KF and the two MF plots. Also on the BF plot a specimen of Id. 8 was sampled together with two plants of Id. 10. Especially plot OF showed a very specific pattern of collected plant species. Most samples found there were sampled on no other plot. Within the climbing species only Dioscorea sp. (Id. I) and Chusquea dombeyana (Id. Q) where non-specific to OF. Within the supporters Ageratina dendroides (Id. 4) was the most abundant species collected on Results 37

OF and only found there. The only non-specific collected host was Persea nectandra (Id. 19). It was sampled on the PA plot at 2700 m a.s.l., too.

Table 3: The distribution of the collected plants among the plots. (Referring to the ID. given in Tab. 1 and Tab. 2 for the climbers and the supporters, respectively. Numbers in brackets are collected samples if more than 1)

OF DF BF PF KF MF I MF II PA

I A (4) B A C (5) A A (3) L (8) K B F (2) F L (4) G E Q (2) Climbers N (2) D G (4) H P I (2) F Q E O L M (2) I R (2) F Q (2) Q (4) Q (4) L (5) S G (2) U T J O

4 (6) 1 2 (2) 2 5 (2) 8 8 (3) 14 (2) 7 3 6 17 8 12 9 15 (2) Supporters 19 10 (2) 8 18 (2) 9 18 11 16 (2) 29 24 (7) 10 (2) 20 12 (2) 22 12 19 31 32 17 21 (2) 13 (2) 23 20 (2) 24 21 (3) 28 (2) 26 24 21 25 32 (2) 32 32 27 23 32 30 (2) 32 32

3.2.3. ASSOCIATIONS BETWEEN THE TWO GROWTH FORMS

The climbers distribution among their host tree species was quite even. Only few supporter/climber-associations, like the Clusia/Bomarea pair or the Vaccinium/Smilax combination, tended to be more frequent (Table 4). All other possible pairs only had frequencies between 0 and 2. Listing and testing also the other climber genera would not make any statistical sense, as their overall abundance in the collection was too low for meaningful results.

Results 38

Table 4: Associations between all host genera and the 7 most important climbers. (n is the total number of collected plants, values in brackets are the number of supporters that carry one of these 7 climbers)

Climbers à Asclepias Bomarea Chusquea Dioscorea Mikania Pentacalia Smilax Supporters â n 5 9 13 5 7 7 19

Ageratina 6 (4) 0 0 1 1 0 0 1

Alzatea 1 (1) 0 0 0 0 1 0 0

Baccharis 2 (2) 1 0 0 0 0 0 1

Befaria 3 (3) 1 0 0 0 0 0 2

Clusia 10 (9) 1 3 0 1 2 1 1

Cybianthus 1 (1) 0 0 0 0 0 0 1

Dictyocarium 1 (1) 0 1 0 0 0 0 0

Eugenia 2 (2) 0 0 2 0 0 0 0

Gauteria 2 (2) 0 0 1 0 0 0 1

Graffenrieda 1 (1) 0 0 1 0 0 0 0

Macrocarpea 3 (3) 0 0 1 0 0 0 1

Miconia 3 (2) 0 1 1 0 0 0 0

Myrsine 1 (1) 0 1 0 0 0 0 0

Palicurea 1 (0) 0 0 0 0 0 0 0

Pentacalia 1 (1) 0 0 0 0 1 0 0

Persea 5 (4) 0 1 0 0 1 0 2

Piper 1 (0) 0 0 0 0 0 0 0

Purdiaea 4 (3) 2 0 0 0 0 0 1

Schefflera 3 (3) 0 0 1 0 0 2 0

Vaccinium 4 (4) 0 0 0 0 0 0 4

Viburnum 1 (0) 0 0 0 0 0 0 0

Weinmannia 1 (1) 0 0 0 0 0 0 1 n.i.1 (Ericaceae) 2 (2) 0 0 1 1 0 0 0 n.i.2 (Lauraceae) 6 (4) 0 0 2 0 0 1 1 n.i.3 (Melast.) 8 (5) 0 1 0 0 1 2 1 n.i.4 (Rubiaceae) 2 (2) 0 0 1 1 0 0 0 n.i.5 (n.i.) 8 (5) 0 1 1 1 0 1 1

A Chi²-test was applied for the three most abundant vines to test if there was statistically significant correlation between the hosts and some single climber genera. Table 5 displays the results of this test and the proportional expected frequencies for the climbers on their host trees. Chi²-values were 32.4, 32.1 and 38.5 for Bomarea, Chusquea and Smilax, respectively. No significant preference for a specific supporter was provable although some correlations were expectable, e.g. between Smilax and Vaccinium or Bomarea and Clusia, as mentioned above.

Results 39

Table 5: Chi²-test results and the calculated proportions of expected frequencies for the three most abundant climber genera.

Climbers à Bomarea Chusquea Smilax Chi² = 32.39 Chi² = 32.06 Chi² = 38.49

Supporters â n p = 0.18 p = 0.19 p = 0.06

Ageratina 6 0 6.38 4.4

Alzatea 1 0 0 0

Baccharis 2 0 0 4.4

Befaria 3 0 0 8.7

Clusia 10 27.7 0 4.4

Cybianthus 1 0 0 4.4

Dictyocarium 1 9.2 0 0

Eugenia 2 0 12.8 0

Gauteria 2 0 6.4 4.4

Graffenrieda 1 0 6.4 0

Macrocarpea 3 0 6.4 4.4

Miconia 3 9.2 6.4 0

Myrsine 1 9.2 0 0

Palicurea 1 0 0 0

Pentacalia 1 0 0 0

Persea 5 9.2 0 8.8

Piper 1 0 0 0

Purdiaea 4 0 0 4.4

Schefflera 3 0 6.4 0

Vaccinium 4 0 0 17.5

Viburnum 1 0 0 0

Weinmannia 1 0 0 4.4

n.i.1 (Ericaceae) 2 0 6.4 0

n.i.2 (Lauraceae) 6 0 12.8 4.4

n.i.3 (Melast.) 8 9.2 0 4.4

n.i.4 (Rubiaceae) 2 0 6.4 0 n.i.5 (n.i.) 8 9.2 6.4 4.4

Results 40

3.3. THE DIFFERENCES IN STRUCTURAL AND NUTRITIONAL PARAMETERS

3.3.1. DIFFERENCES BETWEEN THE GROWTH FORMS

When comparing all plants of both growth forms pair wise (see Tab. 6), the self supporting vegetation had a significantly higher mean single leaf area (LA). Their mature leaves were nearly double sized than the climbers leaves (34.7 vs. 18.3 cm-2, respectively). The climbers leaf mass per unit area (LMA) was only 93.5 g m-2, compared with 163.4 g m-2 of the supporters. Carbon content (C) in tree leaves was significantly higher (46.3 %) than in the climbers (44.1 %). The same result was noticeable for the area based carbon content (Carea), again the supporters had higher values.

Table 6: Mean leaf structure parameters of both growth forms. Significant differences at paired t-test are marked (* p < 0.05 and ** p < 0.01).

LA LMA C Carea [cm2] [g m-2] [%] [mg m-2] Climber 18.3 93.5 44.1 41.7 ** ** ** ** Tree 34.7 163.4 46.3 76.8

Some leaf nutrient contents also differed significantly (Tab. 7). Concerning mass based nitrogen content (Nmass), the climbers had significantly higher contents in their leaves (15.72 mg g-1) than their host trees (12.41 mg g-1). After multiplying LMA with N, the area based nitrogen content (Narea) was calculated. Narea was significantly higher in climber leaves (1843 mg m-2) than in the supporters (1377 mg m-2). Moreover, climbers contained more potassium (K). Aluminium concentration (Al) was higher in the tree leaves. Phosphorus (P) was significantly higher in the climbers leaves. The other investigated elements did not differ significantly between the two groups.

Table 7: Mean element contents in the leaves of both growth forms. Significant differences at paired t-test are marked (* p < 0.05 and ** p < 0.01).

Nmass Narea P K Ca Mg Mn Al [mg g-1] [mg m-2] [mg g-1] [mg g-1] [mg g-1] [mg g-1] [mg g-1] [mg g-1] Climber 15.7 1376.7 0.8 17.52 6.3 3.6 0.7 0.1 ** ** ** ** ** Tree 12.4 1843.7 0.5 12.6 7.0 3.0 0.6 1.3

Results 41

The degree of difference between both growth forms was not the same on all plots. Table 8 and 9 display all investigated elements on the respective plots. Different pattern was obvious especially on the human influenced OF plot. Nearly no differences between the leaves of the climbers and their supporting host trees were noticeable there, except for the percentage of their carbon content. The naturally open plot (PA) in comparison had a wide spectrum of differences, not only in the leaf structure but also in carbon content and most investigated minerals.

Table 8: Mean leaf structure parameters and carbon content of both growth forms (GF; C for climber, T for tree) among all plots. Significant differences at paired t-test are marked (* p < 0.05, ** p < 0.01).

LA LMA C Carea Plot GF [cm2] [g m-2] [%] [mg m-2] OF C 19.4 83.3 44.2 36.8 * T 38.4 111.8 46.3 51.8

DF C 22.7 56.2 41.3 23.3 * ** ** T 64.0 102.1 43.2 44.6 BF C 20.6 72.0 43.2 31.2 ** * * T 34.7 133.8 46.9 63.3 PF C 13.9 67.0 43.8 29.3 * ** ** T 48.8 125.6 43.8 54.7 KF C 12.2 123.2 47.5 58.4 ** * T 11.4 188.2 48.5 90.8 MF I C 19.1 87.2 42.1 36.4 ** ** ** T 47.6 166.1 45.4 75.5 MF II C 22.0 126.7 45.7 58.0 ** ** T 21.0 229.9 47.7 111.5 PA C 15.4 136.7 45.8 62.5 ** * ** T 7.6 255.8 49.0 125.8

Concerning structural leaf parameters that have been investigated, the climbers leaf area (LA) was lower in most cases, but this result was only on two plots significant. On the KF, MF II and PA plots the results were reversed, again not significantly. LMA was significantly higher at the supporters on all plots except for OF (see Tab. 8). Carbon was found to be higher concentrated in the supporters on all plots (significant for five plots).

Higher area based carbon contents (Carea) for the trees were statistically valid, except for OF. Results 42

Table 9: Mean leaf element contents of both growth forms (GF; C for climber, T for tree) among all plots. Significant differences at paired t-test are marked (* p < 0.05, ** p < 0.01).

Nmass Narea P K Ca Mg Mn Al Plot GF [mg g-1] [mg m-2] [mg g-1] [mg g-1] [mg g-1] [mg g-1] [mg g-1] [mg g-1] OF C 18.8 1484.3 1.2 19.1 9.5 4.0 1.0 0.1

T 17.7 1918.1 1.1 18.5 7.2 3.3 1.3 1.0

DF C 15.4 826.5 0.8 29.9 7.7 5.5 1.2 0.1 * * ** * T 13.1 1263.4 0.6 12.0 12.2 4.7 0.9 2.4

BF C 13.8 959.9 0.6 20.3 5.8 4.9 0.5 0.1 ** * T 12.1 1545.2 0.5 12.3 5.0 2.8 0.3 0.3 PF C 14.9 960.5 0.6 15.9 4.5 2.6 0.7 0.1 ** ** * T 12.6 1592.3 0.4 21.1 7.3 2.7 0.3 2.5 KF C 13.5 1637.6 0.6 12.1 5.1 2.6 0.6 0.0 * ** * T 12.4 2223.6 0.4 10.3 2.4 1.8 0.3 0.1 MF I C 19.2 1472.6 0.8 14.2 6.1 3.3 0.6 0.1 ** ** * T 11.6 1790.4 0.5 10.0 5.3 2.6 0.3 2.0 MF II C 13.7 1619.6 0.7 14.4 3.5 3.4 0.5 0.0 ** * T 11.1 2298.4 0.5 8.5 7.5 2.9 0.7 0.5 PA C 16.7 2138.8 0.5 12.2 8.5 2.0 0.2 0.1 ** ** * ** T 8.6 2189.2 0.2 8.3 8.2 3.1 0.9 1.2

Mass based nitrogen (Nmass) content was found to be always higher in the climbers leaves, These findings were statistically valid for two plots (PF and PA). The area based nitrogen contents (Narea) were consistently lower for the climbers, with one exception on PA plot. Phosphorus (P) was significantly higher concentrated in the climbers leaves on four different plots (DF, KF, MF I and PA). Potassium (K) contents were (with one exception on PF) on all plots lower in tree leaves, significantly on two plots (DF and MF I). Only on KF plot the calcium (Ca) concentration was significantly higher in the climbers leaves than in their hosts. On the other plots no differences between the growth forms were found. Leaf magnesium (Mg) content was significantly higher within the supporters on BF, while being significantly lower for the hosts on PF plot. Manganese (Mn) was found to be significantly different between the growth forms on the two plots PF and PA. Twice the climbers had higher manganese contents (PF and BF), while on the sub páramo plot PA the supporters were higher in their content. Aluminium (Al) was significantly different between the two Results 43 growth forms in the dense DF plot. On all plots the host leaves had obviously higher concentrations. (All Tab. 9) See Appendix 6-9 for complete tables with calculated data of standard deviation about the mean values.

3.3.2. DIFFERENCES BETWEEN THE INVESTIGATED PLOTS

Differences between the two growth forms were already described above. This chapter deals with the differences between the single plots and the different patterns shown by the two growth forms. Tables 10 to 20 display the results derived after ANOVA testing. A maximum of 24 differences could be found by comparing the eight plots among themselves. Especially the plots with the most different light and LAI conditions were expected to distinguish most. More or less similar plots on the other hand should not differ that much in the leaf parameters of the two plant types.

LMA of the climbers was different between the plots in 13 cases, for the trees only 11 times (see Tab. 10). With increasing altitude LMA generally increased in the climber and tree samples from 83.3 and 111.8 g m-2 to 136.7 and 255.8 g m-2, respectively. The plots MF II and PA differed in both growth forms on most lower plots. Within the climbers, plot KF was also different from three other plots (DF, BF and PF); within the supporters only compared with DF and MF I.

Table 10: Differences in leaf mass per unit area of both growth forms between the single plots. Light grey boxes show the climbers, dark grey boxes their supporters. Significant differences (ANOVA) are marked (* p < 0.05, ** p < 0.01, - p > 0.05).

LMA OF DF BF PF KF MF I MF II PA OF - - - - - * ** DF - - - ** - ** ** BF - - - ** - ** ** PF - - - ** - ** ** KF - * - - - - - MF I - - - - ** * ** MF II ** ** ** ** - - - PA ** ** ** ** - * -

Results 44

Slightly more differences were found between the plots within the climbers (10/24) than within trees (7/24) regarding leaf carbon contents (C [%]). The distribution pattern of leaf carbon was not the same in the two groups and ranged from 41.3 to 49.0 %. KF plot was different from five plots within the climbers, but only from two among the trees (Tab. 11).

Table 11: Differences in carbon content of both growth forms between the single plots. Light grey boxes show the climbers, dark grey boxes their supporters. Significant differences (ANOVA) are marked (* p < 0.05, ** p < 0.01, - p > 0.05)

C [%] OF DF BF PF KF MF I MF II PA OF * - - * - - - DF - - - ** - ** ** BF - * - ** - - - PF - - - ** - - - KF - ** - ** ** - - MF I - - - - - ** ** MF II - ** - * - - - PA - ** - ** - - -

Area based carbon (Carea) was more different among the plots within the climbers (e.g.

-2 -2 KF plot). Carea of the plants on PA (Climbers: 62.5 mg m , Trees: 125.8 mg m ) and MF II (Climbers: 58.1 mg m-2, Trees: 11.5 mg m-2) differed from most other plots within both growth forms (Climbers: < 36.7 mg m-2, Trees: < 90.8 mg m-2). (see Tab. 12)

Table 12: Differences in area based carbon content of both growth forms between the single plots. Light grey boxes show the climbers, dark grey boxes their supporters. Significant differences (ANOVA) are marked (* p < 0.05, ** p < 0.01, - p > 0.05)

Carea OF DF BF PF KF MF I MF II PA OF - - - ** - ** ** DF - - - ** - ** ** BF - - - ** - ** ** PF - - - ** - ** ** KF - ** - - ** - - MF I - - - - - ** ** MF II ** ** ** ** - - - PA ** ** ** ** - ** - Results 45

Mass based nitrogen (Nmass) was nearly constant among the altitudinal gradient. As displayed in Table 13, differences in Nmass were evident only within the trees, while the climbers nitrogen content did never change significantly between the plots. Considering

-1 the supporters, the anthropogenous opened OF plot with its tree leaf Narea of 17.7 mg g differed from four other plots (BF, MF I, MF II and PA) where Narea was all time significantly lower.

Table 13: Differences in mass based nitrogen content of both growth forms between the single plots. Light grey boxes show the climbers, dark grey boxes their supporters. Significant differences (ANOVA) are marked (* p < 0.05, ** p < 0.01, - p > 0.05)

Nmass OF DF BF PF KF MF I MF II PA OF ------DF ------BF * ------PF ------KF ------MF I * ------MF II ** ------PA ** ------

Area based nitrogen (Narea) did not differ much between the single plots for the trees

-2 - (see Tab. 14). DF with Narea of 1263 mg m was for example differing from KF (1638 mg m 2) and MF II (1620 mg m-2). The climbers on the other hand showed in 19 of 24 possible comparisons significant differences for this leaf trait between the plots. Especially the dense plots of the lower altitudes (DF, BF and PF) with values between 827 and

-2 960 mg m differed seriously from the open plots (OF, KF, MF I and MF II) with leaf Narea between 1472 and 1637 mg m-2. Climber leaves from PA showed an extraordinarily high

-2 Narea value of 2138 mg m , which was quite comparable with the leaves of their hosts.

Results 46

Table 14: Differences in area based nitrogen content of both growth forms between the single plots. Light grey boxes show the climbers, dark grey boxes their supporters. Significant differences (ANOVA) are marked (* p < 0.05, ** p < 0.01, - p > 0.05)

Narea OF DF BF PF KF MF I MF II PA OF ** ** ** - - - ** DF - - - ** ** ** ** BF - - - ** ** ** ** PF - - - ** ** ** ** KF - ** - - - - * MF I ------** MF II - ** * * - - ** PA - ** - - - - -

Differences in leaf phosphorus content (P) between the plots showed comparable patterns for both growth forms. OF was distinguishable from all other plots with its significantly higher leaf P contents in both growth forms. Within the trees, significant differences between the leaf phosphorus on PA (0.2 mg m-2) and the four other plots OF, DF, BF and MF I (0.5 to 1.1 mg m-2)(Tab. 15) could be found.

Table 15: Differences in phosphorus content of both growth forms between the single plots. Light grey boxes show the climbers, dark grey boxes their supporters. Significant differences (ANOVA) are marked (* p < 0.05, ** p < 0.01, - p > 0.05)

P OF DF BF PF KF MF I MF II PA OF * ** ** ** * ** ** DF ** ------BF ** ------PF ** ------KF ** ------MF I ** ------MF II ** ------PA ** ** * - - * -

Potassium (K) content of the trees was constantly between 10.0 and 18.5 mg m-2 among the plots OF, DF, BF, KF and MF I. PF with its high value of 21.3 mg m-2 differed significantly from the low valued plots MF II (8.5 mg m-2) and PA (8.3 mg m-2). Within the Results 47 climbers, DF (29.9 mg m-2) differed significantly from six other plots (OF, PF, KF, MF I, MF II and PA) with leaf K contents between 12.2 and 19.1 mg m-2 (Tab. 16).

Table 16: Differences in potassium content of both growth forms between the single plots. Light grey boxes show the climbers, dark grey boxes their supporters. Significant differences (ANOVA) are marked (* p < 0.05, ** p < 0.01, - p > 0.05)

K OF DF BF PF KF MF I MF II PA OF * ------DF - - ** ** ** ** ** BF ------PF ------KF ------MF I ------MF II - - - * - - - PA - - - * - - -

Leaf calcium (Ca) content was nearly constant within each growth form among the plots (Tab. 17). Climbers on plot MF II had the lowest leaf Ca (3.5 mg g-1), while on OF plot significant higher concentrations were evident (9.5 mg g-1). Calcium content of tree leaves was different between DF (12.2 mg g-1) and the plots BF and KF (5.0 and 2.4 mg g-1, respectively).

Table 17: Differences in calcium content of both growth forms between the single plots. Light grey boxes show the climbers, dark grey boxes their supporters. Significant differences (ANOVA) are marked (* p < 0.05, ** p < 0.01, - p > 0.05)

Ca OF DF BF PF KF MF I MF II PA OF - - - - - * - DF ------BF - * - - - - - PF ------KF - * - - - - - MF I ------MF II ------PA ------

Results 48

As shown in table 18, leaf magnesium (Mg) was significantly lower in climber samples from PA plot (2.0 mg g-1) than in the climbers of DF plot (4.7 mg g-1). The tree leaf samples collected on DF plot had significantly higher Mg contents (4.7 mg g-1) than the samples from most other plots (< 2.9 mg g-1), with the exception of PA and OF plot, where the plants also had Mg contents above 3 mg g-1.

Table 18: Differences in magnesium content of both growth forms between the single plots. Light grey boxes show the climbers, dark grey boxes their supporters. Significant differences (ANOVA) are marked (* p < 0.05, ** p < 0.01, - p > 0.05)

Mg OF DF BF PF KF MF I MF II PA OF ------DF ------** BF - * - - - - - PF - * - - - - - KF - ** - - - - - MF I - * - - - - - MF II - * - - - - - PA ------

The climbers leaf manganese (Mn) content differed significantly only between the two plots DF and PA, with values of 1.2 mg g-1and 0.2 mg g-1, respectively. Within the trees more differences between the single plots were evident. Especially OF samples were significantly higher in Mn (1.25 mg g-1) than the samples from most other plots (BF,PF,KF and MF I). Supporters from PF plot (0.3 mg g-1) were significantly lower in their leaf Mn than on MF II and PA (0.7 and 0.9 mg g-1, respectively) (Tab. 19).

Leaf aluminium (Al) content often varied among the plots. In both growth forms yet no significant differences were evident between the samples of the single plots, neither within the climbers, nor within their hosts (Tab. 20).

Results 49

Table 19: Differences in manganese content of both growth forms between the single plots. Light grey boxes show the climbers, dark grey boxes their supporters. Significant differences (ANOVA) are marked (* p < 0.05, ** p < 0.01, - p > 0.05)

Mn OF DF BF PF KF MF I MF II PA OF ------DF ------** BF ** ------PF ** ------KF ** ------MF I ** ------MF II - - - * - - - PA - - - * - - -

Table 20: Differences in aluminium content of both growth forms between the single plots. Light grey boxes show the climbers, dark grey boxes their supporters. Significant differences (ANOVA) are marked (* p < 0.05, ** p < 0.01, - p > 0.05)

Al OF DF BF PF KF MF I MF II PA OF ------DF ------BF ------PF ------KF ------MF I ------MF II ------PA ------

3.3.3. LEAF PARAMETERS OF THE INVESTIGATED GENERA

Significant differences between the two growth forms were found concerning most parameters (Chapter 3.3.1., Tab. 6-9). To test whether these differences are driven by some single plants that accumulate huge amounts of a specific element in their leaves, the values of all investigated parameters were plotted according to plant genera (see Figures 12 to 23). Some investigated plants showed a specific nutrient content, differing Results 50 from most other genera. Many plants had comparable leaf contents of a single element, but there where also some cases where outstanding high concentrations were recognisable. The following describes the leaf element contents under special emphasis to genera with such remarkable contents:

Leaf area (LA) was at a quite constant low level along the altitudinal gradient for the collected climber genera (see Fig. 11). The largest leaves (up to 49.7 cm2) were found on some genera from the shaded plots DF and BF (Orthea, Pentacalia and Topobea), but with Banisteriopsis also a genus from the KF plot with great irradiance level. On this plot two genera with very small leaves were abundant, too (Asclepias and Myrsine), while most other plants with remarkable small leaves (<5 cm2) were sampled on the OF plot (see Fig. 12).

250 Tree Outliers 200 Extremes Climber Outliers 150 Extremes ] 2 100 LA [cm 50

0

-50 1930 2020 2090 2135 2230 2280 2330 2700 Altitude [m a.s.l.]

Figure 11: Mean leaf area (LA) with standard deviation of the collected samples along the altitudinal gradient. (Solid boxes show trees, light boxes the climbers.)

Within the host genera much greater variation in leaf size was obvious. Supporter leaves were generally larger compared to those of climbers. Maximum host leaf sizes (up to 244.9 cm2) were found in the genera Dictyocarium, Macrocarpea and Piper, all growing on different plots. The smallest leaves of this growth form were derived from plants mostly out of the Ericaceae family, growing on the plots of upper altitudes (see also Fig. 12).

Results 51

250 Mean+SD 225 Mean-SD 200 Mean Outliers 175 Extremes 150 125 ]

2 100 75

LA [cm 50 25 0 ? Cissus Smilax Mikania Myrsine Orthaea Banister Topobea Bomarea Valeriana Asclepias Dioscorea Chusquea Pentacalia Gonioanthela Muehlenbeckia 250 Mean+SD 225 Mean-SD Mean 200 Outliers 175 Extremes 150 125 ] 2 100 75 LA [cm 50 25 0 ? Piper Clusia Befaria Persea Alzatea Miconia Myrsine Eugenia Gauteria Purdiaea Palicurea Ageratina Viburnum Baccharis Schefflera Vaccinium Pentacalia Cybianthus Graffenrieda Weinmannia Dictyocarium Macrocarpea

Figure 12: Leaf area (LA) of the collected plant genera. (Solid boxes are supporters, open boxes the climbers)

Results 52

While most climbers nearly remained constant in their leaf mass per unit area (LMA), the supporters differed much within their genera (see Fig. 13). Especially some plants from the genera Clusia, Gauteria, Graffenrieda and Vaccinium had extremely heavy built leaves (up to 394.0 g m-2). With some exceptions in the Clusia genus, most of these plants were abundant on the open plots of the upper altitudes (KF to PA). The two supporter genera with the lowest LMA values (minimum 65.8 g m-2), Dictyocarium and Pentacalia, were found in dense plots in the lower parts of the investigation area (DF, BF).

450 Mean+SD 400 Mean-SD Mean 350 Outliers 300 Extremes 250 ]

-2 200 150 100 LMA [g m 50 0 ? Cissus Smilax Mikania Myrsine Orthaea Banister Topobea Bomarea Valeriana Asclepias Dioscorea Chusquea Pentacalia Gonioanthela Muehlenbeckia 450 Mean+SD 400 Mean-SD Mean 350 Outliers Extremes 300

250 ]

-2 200

150

100 LMA [g m 50

0 ? Piper Clusia Befaria Persea Alzatea Miconia Myrsine Eugenia Gauteria Purdiaea Palicurea Ageratina Viburnum Baccharis Schefflera Vaccinium Pentacalia Cybianthus Graffenrieda Weinmannia Dictyocarium Macrocarpea

Figure 13: Leaf mass per unit area (LMA) of the leaves of the collected plant genera. (Solid boxes are supporters, open boxes the climbers) Results 53

Carbon content (C) in the climbers leaves was highest in the genera Asclepias, Myrsine and Smilax (up to 51.4 %) (Fig. 14), collected mainly on the KF plot and even in higher altitudes. Lowest contents (minimum 44.1 %) were found in leaves of the genera Gonioanthela and Orthaea, both from the DF plot. The carbon content of the supporters leaves was generally higher. Lowest leaf carbon was found in the genera Dictyocarium, Palicurea and Pentacalia (min. 38.7 %) on plot OF, DF and BF, highest contents in Befaria, Gauteria and Vaccinium (up to 55.7 %) (KF, PA).

54 52 50 48 46 44 42 Mean+SD C [%] 40 Mean-SD 38 Mean Outliers 36 Extremes ? Cissus Smilax Mikania Myrsine Orthaea Banister Topobea Bomarea Valeriana Asclepias Dioscorea Chusquea Pentacalia Gonioanthela Muehlenbeckia

54 52 50 48 46 44 42

C [%] Mean+SD 40 Mean-SD 38 Mean Outliers 36 Extremes ? Piper Clusia Befaria Persea Alzatea Miconia Myrsine Eugenia Gauteria Purdiaea Palicurea Ageratina Viburnum Baccharis Schefflera Vaccinium Pentacalia Cybianthus Graffenrieda Weinmannia Dictyocarium Macrocarpea

Figure 14: Content of carbon (C) in the leaves of the collected plant genera. (Solid boxes are supporters, open boxes the climbers) Results 54

The different climber genera had a quite constant area based carbon content (Carea) in their leaves (Fig. 15). Carea content and variation within their supporters was much higher. Befaria, Clusia, Gauteria, Graffenrieda, Persea and Vaccinium from the upper altitudes built a group with high contents (up to 219.2 g m-2), while Dictyocarium and Pentacalia

-2 from DF and BF plot tended to be lower in Carea (min. 27.3 g m ) than the other genera (mean 76.8 g m-2). These results were strongly related to leaf structure (LMA).

Mean+SD Mean-SD 200 Mean Outliers Extremes 150 ]

-2 100 [g m

area 50 C

0 ? Cissus Smilax Mikania Myrsine Orthaea Banister Topobea Bomarea Valeriana Asclepias Chusquea Pentacalia Dioscoreea Gonioanthela Muehlenbeckia

Mean+SD Mean-SD 200 Mean Outliers Extremes 150 ] -2 100 [g m area

C 50

0 ? Piper Clusia Befaria Persea Alzatea Miconia Myrsine Eugenia Gauteria Purdiaea Palicurea Ageratina Viburnum Baccharis Schefflera Vaccinium Pentacalia Cybianthus Graffenrieda Weinmannia Dictyocarium Macrocarpea

Figure 15: Content of area based carbon (Carea) in the leaves of the collected plant genera. (Solid boxes are supporters, open boxes the climbers) Results 55

Mass based nitrogen content (Nmass) was distributed quite equally among the genera of both growth forms (Fig. 16). Within the climbers, slightly higher contents were found within the leaves of Chusquea, Dioscorea, Gonioanthela and Muehlenbeckia. The abundance of these plants was not limited to specific plots, altitudes or radiation levels. Within the supporters only the values of Piper, from the secondary vegetation of the OF plot, were extraordinarily high (35.3 mg g-1) in its nitrogen content.

40 Mean+SD Mean-SD 35 Mean 30 Outliers Extremes 25

] 20 -1 15 [mg g 10 mass

N 5

0 ? Cissus Smilax Mikania Myrsine Orthaea Banister Topobea Bomarea Valeriana Asclepias Dioscorea Chusquea Pentacalia Gonioanthela Muehlenbeckia 40 Mean+SD 35 Mean-SD Mean 30 Outliers Extremes 25 ]

-1 20

15 [mg g 10 mass N 5

0 ? Piper Clusia Befaria Persea Alzatea Miconia Myrsine Palicure Eugenia Gauteria Purdiaea Ageratina Viburnum Baccharis Schefflera Vaccinium Pentacalia Cybianthus Graffenrieda Weinmannia Dictyocarium Macrocarpea

Figure 16: Content of nitrogen (Nmass) in the leaves of the collected plant genera. (Solid boxes are supporters, open boxes the climbers)

Results 56

Area based leaf nitrogen (Narea) did not differ much between the climber genera. Only Cissus from BF plot had lower contents than the other genera. In some Smilax specimen

-1 high Narea values (max. 2860.1 mg g ) were evident. Within the supporters larger variations could be recognised. Plants of the genera Dictyocarium and Pentacalia from DF and BF plot were situated at the lower end of the value range (min. 553.3 mg g-1), while Piper and some Persea and Agaretina specimens mainly from OF plot had the highest leaf

Narea (Fig. 17).

3500 Mean+SD Mean-SD 3000 Mean Outliers 2500 Extremes

2000 ] -2 1500

1000 [mg m

area 500 N

0 ? Cissus Smilax Mikania Myrsine Orthaea Banister Topobea Bomarea Valeriana Asclepias Dioscorea Chusquea Pentacalia Gonioanthela Muehlenbeckia 3500

3000

2500

2000 ] -2 1500

[mg m 1000 Mean+SD

area Mean-SD

N 500 Mean Outliers 0 Extremes ? Piper Clusia Befaria Persea Alzatea Miconia Myrsine Eugenia Gauteria Purdiaea Palicurea Ageratina Viburnum Baccharis Schefflera Vaccinium Pentacalia Cybianthus Graffenrieda Weinmannia Dictyocarium Macrocarpea

Figure 17: Content of area based nitrogen (Narea) in the leaves of the collected plant genera. (Solid boxes are supporters, open boxes the climbers) Results 57

Phosphorus (P) content of Valeriana leaves from OF plot (max. 1.6 mg g-1)was the only that differed clearly from the other climber genera (Fig. 18). Within the supporters, Ageratina, Dictyocarium and Piper had highest contents. Only Dictyocarium was not collected on OF plot, but on nearby DF plot. The other values were quite equal within most supporter genera, with slightly lower contents in leaves of the Ericaceae Befaria, Gauteria and Vaccinium, and the genera Graffenrieda and Purdiaea. These samples were collected on the most exposed plots.

2.5 Mean+SD Mean-SD 2.0 Mean Outliers Extremes 1.5 ]

-1 1.0

0.5 P [mg g

0.0 ? Cissus Smilax Mikania Myrsine Orthaea Banister Topobea Bomarea Valeriana Asclepias Dioscorea Chusquea Pentacalia Gonioanthla

Muehlenbeckia 2.5 Mean+SD Mean-SD Mean 2.0 Outliers Extremes

1.5 ] -1 1.0

P [mg g 0.5

0.0 ? Piper Clusia Befaria Persea Alzatea Miconia Myrsine Eugenia Gauteria Purdiaea Palicurea Ageratina Viburnum Baccharis Schefflera Vaccinium Pentacalia Cybianthus Graffenrieda Weinmannia Dictyocarium Macrocarpea

Figure 18: Content of phosphorus (P) in the leaves of the collected plant genera. (Solid boxes are supporters, open boxes the climbers) Results 58

The climbing genera Bomarea, Gonioanthela, Mikania and Pentacalia built a group with high potassium contents (K) in their leaves (max. 49.0 mg g-1). They all were abundant along a wide range of altitudes and radiation levels. Within the supporters, only the genera Macrocarpea and Piper had higher contents. Both were growing under varying conditions. (See Fig. 19)

60 Mean+SD Mean-SD 50 Mean Outliers 40 Extremes

30

] 20 -1

10

K [mg g 0

-10 ? Cissus Smilax Mikania Myrsine Orthaea Banister Topobea Bomarea Valeriana Asclepias Dioscorea Chusquea Pentacalia Gonioanthela Muehlenbeckia 60 Mean+SD Mean-SD 50 Mean Outliers 40 Extremes

30 ]

-1 20

10 K [mg g 0

-10 ? Piper Clusia Befaria Persea Alzatea Miconia Myrsine Eugenia Gauteria Purdiaea Palicurea Ageratina Viburnum Baccharis Schefflera Vaccinium Pentacalia Cybianthus Graffenrieda Weinmannia Dictyocarium Macrocarpea

Figure 19: Content of potassium (K) in the leaves of the collected plant genera. (Solid boxes are supporters, open boxes the climbers)

Results 59

The supporter’s leaves from the genera Macrocarpea and Viburnum tend to have higher calcium (Ca) contents. These two genera were not restricted to specific plots. The climber genera did not differ much in their leaf calcium contents (Fig. 20).

35 Mean+SD 30 Mean-SD Mean 25 Outliers Extremes 20

15 ] -1 10

5

Ca [mg g 0

-5 ? Cissus Smilax Mikania Myrsine Orthaea Banister Topobea Bomarea Valeriana Asclepias Dioscorea Chusquea Pentacalia Gonioanthela Muehlenbeckia 35 Mean+SD 30 Mean-SD Mean 25 Outliers Extremes 20

] 15 -1 10

5 Ca [mg g 0

-5 ? Piper Clusia Befaria Persea Alzatea Miconia Myrsine Eugenia Gauteria Purdiaea Palicurea Ageratina Viburnum Baccharis Schefflera Vaccinium Pentacalia Cybianthus Graffenrieda Weinmannia Dictyocarium Macrocarpea

Figure 20: Content of calcium (Ca) in the leaves of the collected plant genera. (Solid boxes are supporters, open boxes the climbers)

Leaf magnesium (Mg) was distributed quite equally among most climbing genera (Fig. 21). Only Chusquea, Myrsine and Orthaea, all growing on different plots, had lower Results 60 mean Mg contents (min. 0.5 mg g-1). Like the climbers, the supporters leaf Mg was about 3.5 mg g-1 most of the time. Only the genera Piper, Viburnum and Vaccinium had somewhat higher contents (> 5 mg g-1). These samples were collected on plots with high radiation input, either OF or PA plot.

15 Mean+SD Mean-SD Mean Outliers 10 Extremes ] -1 5 Mg [mg g 0 ? Cissus Smilax Mikania Myrsine Orthaea Banister Topobea Bomarea Valeriana Asclepias Dioscorea Chusquea Pentacalia Gonioanthela Muehlenbeckia 15 Mean+SD Mean-SD Mean Outliers 10 Extremes ] -1 5 Mg [mg g

0 ? Piper Clusia Befaria Persea Alzatea Miconia Myrsine Eugenia Gauteria Purdiaea Palicurea Ageratina Viburnum Baccharis Schefflera Vaccinium Pentacalia Cybianthus Graffenrieda Weinmannia Dictyocarium Macrocarpaea

Figure 21: Content of magnesium (Mg) in the leaves of the collected plant genera. (Solid boxes are supporters, open boxes the climbers)

The climbing genera differed much in their leaf manganese content (Mn) (Fig. 22). Especially Muehlenbeckia from OF plot had a very high mean content of 2.1 mg g-1. The Results 61 other genera can be divided in two main groups. Asclepias, Bomarea, Dioscorea and Gonioanthela had high contents, all collected on different plots, while the other genera had lower contents. The supporter genera Ageratina, Piper, Vaccinium and Viburnum were characterised by high leaf manganese contents (> 1.5 mg g-1). These supporters showed restrictions toward those sites with high radiation input.

2.8 Mean+SD 2.4 Mean-SD Mean 2.0 Outliers Extremes 1.6

1.2 ] -1 0.8

0.4

Mn [mg g 0.0

-0.4 ? Cissus Smilax Mikania Myrsine Orthaea Banister Topobea Bomarea Valeriana Asclepias Chusquea Pentacalia Dioscoreea Gonioanthela Muehlenbeckia 2.8 Mean+SD 2.4 Mean-SD Mean 2.0 Outliers Extremes 1.6

] 1.2 -1 0.8

0.4 Mn [mg g 0.0

-0.4 ? Piper Clusia Befaria Persea Alzatea Miconia Myrsine Palicure Eugenia Gauteria Purdiaea Ageratina Viburnum Baccharis Schefflera Vaccinium Pentacalia Cybianthus Graffenrieda Weinmannia Dictyocarium Macrocarpea

Figure 22: Content of manganese (Mn) in the leaves of the collected plant genera. (Solid boxes are supporters, open boxes the climbers)

Results 62

Aluminium (Fig. 23) was highest in the leaves of the climber genus Muehlenbeckia from the OF plot (0.5 mg g-1). Within the self supporting vegetation the genera Macrocarpea, Miconia and Palicurea had evidently high leaf aluminium contents with means of more than 9 mg g-1, by far exceeding the range of all other collected specimens (mostly < 1 mg g-1). The accumulator plants were collected on different plots (PF, DF, MF I, MF II and PA).

1.0 Mean+SD 0.9 Mean-SD 0.8 Mean 0.7 Outliers Extremes 0.6 0.5

] 0.4 -1 0.3 0.2

Al [mg g 0.1 0.0 -0.1 ? Cissus Smilax Mikania Myrsine Orthaea Banister Topobea Bomarea Valeriana Asclepias Dioscorea Chusquea Pentacalia Gonioanthela Muehlenbeckia 15 Mean+SD 14 Mean-SD 13 Mean 12 11 Extremes 10 9 8

] 7

-1 6 5 4 3 Al [mg g 2 1 0 -1 ? Piper Clusia Befaria Persea Alzatea Miconia Myrsine Eugenia Vacciniu Gauteria Purdiaea Palicurea Ageratina Viburnum Baccharis Schefflera Pentacalia Cybianthus Graffenrieda Weinmannia Dictyocarium Macrocarpea

Figure 23: Content of Aluminium (Al) in the leaves of the collected plant genera. (Solid boxes are supporters, open boxes the climbers; note the different scales for supporters and climbers!) Results 63

3.4. LEAF PARAMETERS AND ENVIRONMENT

As light plays a major role in plant development, different conditions should be represented in the leaves of a plant. Table 21 gives an overview about the calculated regressions between PFDrel above the samples and the investigated leaf parameters.

LMA, C, Carea, Narea and Mn were significantly correlated with light in both growth forms.

Climber leaves also showed negative correlation for K and Mg with PFDrel, while LA was correlated with light only within the trees. A closer look upon the changes of some selected structural parameters and element contents in dependency of PFDrel is given in the figures 24 to 27.

Table 21: Regression between PFDrel above the samples and each investigated leaf parameter with p-level, r² and Standard error of estimate. (Highlighted if p < 0.05)

Std.Error of GF Linear regression (±Std.Dev.) p-level r² estimate

C y = -0.04 (±2.10) x + 18.23 (±3.84) 0.99 < 0.01 12.2 LA T y = -33.82 (±12.12) x + 49.07 (±6.64) <0.01 0.09 38.5 C y = 70.25 (±10.07) x + 63.83 (±5.52) <0.01 0.37 32.0 LMA T y = 103.49 (±21.47) x + 119.70 (±11.68) <0.01 0.22 68.2 C y = 3.21 (±0.81) x + 42.78 (±0.44) <0.01 0.16 2.6 C T y = 4.32 (±0.94) x + 44.44 (±0.51) <0.01 0.21 3.0 C y = 33.86 (±4.71) x + 27.41 (±2.58) <0.01 0.39 15.0 Carea T y = 55.74 (±10.96) x + 53.28 (±6.00) <0.01 0.24 34.8 C y = 0.99 (±1.55) x + 15.30 (±0.85) 0.52 0.05 4.9 Nmass T y = -0.58 (±1.41) x + 12.66 (±0.77) 0.68 <0.01 4.5 C y = 1069.0 (±166.9) x + 924.9 (±61.2) <0.01 0.53 354.5 Narea T y = 875.0 (±166.9) x + 1481.5 (±91.4) <0.01 0.25 529.8 C y = 0.05 (±0.11) x + 0.73 (±0.06) 0.66 0.02 0.4 P T y = 0.04 (±0.11) x + 0.51 (±0.06) 0.72 0.02 0.3 C y = -9.71 (±2.72) x + 21.63 (±1.51) <0.01 0.12 8.7 K T y = -4.31 (±2.75) x + 14.38 (±1.51) 0.12 0.03 8.7 C y = 1.86 (±1.38) x + 5.55 (±0.74) 0.17 0.01 4.3 Ca T y = -1.59 (±0.48) x + 7.72 (±1.01) 0.38 0.01 5.8 C y = -1.91 (±0.73) x + 4.38 (±0.40) <0.05 0.08 2.3 Mg T y = -0.56 (±0.48) x + 3.25 (±0.26) 0.24 0.02 1.5 C y = -0.39 (±0.19) x + 0.83 (±0.11) <0.05 0.05 0.6 Mn T y = 0.41 (±1.87) x + 0.45 (±0.10) <0.01 0.06 0.6 C y = -0.04 (±0.03) x + 0.11 (±0.02) 0.27 <0.01 0.1 Al T y = -1.18 (±0.87) x + 1.76 (±0.48) 0.18 0.02 2.8

Results 64

With changing light conditions, the average leaf area of plants (LA) should also change. Larger leaves can rather be expected under deep shade than on sites exposed to sunlight. However, the sampled climber leaves from the shady plots did not differ from the plots with high radiation input (Fig. 24), here displayed as relative photon flux density

(PFDrel). There was no significant correlation between the average leaf area of single leaves (LA) and PFDrel. The samples of the supporting trees on the other hand showed a significant, but weak negative correlation between leaf area and increasing PFDrel. The variation of the sampled tree leaves under given light conditions was higher than within the climber leaves (standard error of estimate: 38.5 and 12.2 for the supporters and the climber leaves, respectively). Results still remained the same when excluding OF plot with its pioneer vegetation (not shown).

250 Climber Tree

200

150 ] 2

LA [cm 100

50

0 0,0 0,2 0,4 0,6 0,8 1,0 PFD rel

Figure 24: Average leaf area (LA) under the observed relative light input (PFDrel), with fitted regression lines for each growth form.

Figure 25 displays the differences between the two growth forms in leaf mass per unit area (LMA) under observed light conditions. LMA was slightly positively correlated with

PFDrel in both growth forms. Calculated regressions differed between the plant types, as displayed in Table 21. Correlation between the factors was higher within the climbers (r² = 0.37) than within the trees (r² = 0.22). Standard error of estimate was lower (32.0) for climber leaves than for leaves of the self supporting vegetation (68.2). Results 65

450 Climber 400 Tree

350

300 ] -2 250

200

LMA [g m 150

100

50

0 0,0 0,2 0,4 0,6 0,8 1,0 PFD rel

Figure 25: Leaf mass per unit area (LMA) under the observed relative light input (PFDrel), with fitted regression lines for each growth form.

Mass based nitrogen content (Nmass) was higher within the leaves of climbers. This was evident under all observed light conditions (Fig. 26). Unlike the results for LMA, no correlation was found between radiation and nitrogen within both growth forms. The distribution of the observed values around the regression line was nearly the same in the two groups. Calculated regressions were not significant and did also not differ.

Area based nitrogen content (Narea) had quite comparable patterns as LMA (Fig. 27). The leaves of supporting trees were higher in Narea along the light gradient than leaves of the climbing vegetation. The linear equation of regression for both growth forms is given in

Table 21. Higher correlation between PFDrel and Narea was evident within the climbers (r² = 0.53, p < 0.01) than within their host trees (r² = 0.25, p < 0.01). Again the climbers had lower variations under the given radiation values (standard error of estimate: 529.8 and 354.5 for the supporters and the climbers leaves, respectively). This indicates a better adaptation to the prevailing conditions of the climbing growth form than of the self- supporting vegetation.

Results 66

Climber 36 Tree

30 ]

-1 24

[mg g 18 mass N 12

6

0 0,0 0,2 0,4 0,6 0,8 1,0 PFD rel

Figure 26: Mass based nitrogen content under the observed relative light input (PFDrel), with fitted regression lines for each growth form.

4000 Climber Tree 3500

3000

] 2500 -2

2000 [mg m

area 1500 N

1000

500

0 0,0 0,2 0,4 0,6 0,8 1,0 PFD rel

Figure 27: Area based nitrogen content under the observed relative light input (PFDrel), with fitted regression lines for each growth form.

Results 67

LMA and Nmass had a strongly negative relationship within the collected leaves of both growth forms (Fig. 28). Linear regression differed between the two groups concerning their intercept, but not in their gradient (y = -0.06 (± 0.01) x + 21.21 (± 1.18), r² = 0.23, p < 0.01 for the climbers leaves and y = -0.03 (± 0.05) x + 17.58 (± 0.97) ,r² = 0.29, p < 0.01 for their hosts, respectively). The standard error of estimate was on comparable level between the climbers (4.34) and their hosts (3.76).

Climber 36 Tree

30 ]

-1 24

[mg g 18 mass N 12

6

0 0 50 100 150 200 250 300 350 400 450 LMA [g m-2]

Figure 28: Relationship between LMA and Nmass, with regression lines for each growth form.

Nitrogen concentration on leaf area basis (Narea) showed positive correlation with LMA within the climber samples (y = 9.76 (± 0.92) x + 463.9 (± 93.47), r² = 0.58, p < 0.01) (Fig. 29). The tree leaves also showed a strong positive correlation between these factors (y = 5.06 (± 0.62) x + 1016.5 (± 121.2) , r² = 0.41, p < 0.01). Intercept and gradient were different between the regressions of the climbers and their hosts. Standard error of estimate was lower for the climbers (334.6) than for the trees (467.6).

Results 68

4000

3500

3000

] 2500 -2

2000 [mg m

area 1500 N

1000

500 Climber Tree 0 0 50 100 150 200 250 300 350 400 450 LMA [g m-2]

Figure 29: Relationship between LMA and Narea, with regression lines for each growth form.

Results 69

3.5. SYNTHESIS OF LEAF PARAMETERS A Principle Components Analysis (PCA) was applied on the dataset to reduce the number of factors by grouping strongly correlated variables. As the OF plot obviously was in an successional status, and therefore not comparable with the other seven investigation plots, it was excluded in this part of the evaluation.

3.5.1. FACTOR LOADINGS OF THE PCA

Table 22 displays the results for the self supporting vegetation. With a minimum Eigenvalue limit at 1.000, four factors were derived that explained 77.1 % of the total variance. Maximum Eigenvalue was 5.18 in Factor 1, explaining 39.8 % of the total variance. The variables Altitude, PFDrel, LMA, Carea and Narea were grouped together in that first factor. Factor 2 with 18.8 % of total variance included Ca and Mn. The variables Nmass and P were the main components of Factor 3 that explained 9.6 % of the total variance. In Factor 4 K and Al were grouped as the main variables (8.9 % of the total variance).

Table 22: The supporters Eigenvalues, percentage of total variance and factor loadings of the PCA after Varimax normalized rotation. (Marked loadings are > 0.7)

Factor 1 Factor 2 Factor 3 Factor 4 Eigenvalue 5.18 2.45 1.25 1.16 % total Variance 39.8 18.8 9.6 8.9 Altitude a.s.l. 0.831 -0.038 0.256 -0.043

PFDrel 0.892 -0.009 0.162 0.059 LMA 0.795 0.007 0.402 0.247 C [%] 0.511 0.482 0.293 0.293

Carea 0.800 0.051 0.408 0.266

Nmass -0.165 0.135 -0.925 -0.081

Narea 0.824 0.201 -0.227 0.207 P -0.361 -0.043 -0.798 -0.041 K -0.188 0.110 -0.203 -0.803 Ca -0.107 -0.871 0.200 -0.263 Mg -0.038 -0.472 -0.307 0.079 Mn 0.053 -0.893 0.142 0.011 Al -0.128 -0.284 0.097 -0.835

Results 70

The results of the PCA for the climbers (Table 23) were quite comparable with the results for their host trees. Again four factors were derived from the original set of variables, describing 78.2 % of the total variance. Factor loadings were generally higher than within the trees. Factor 1 had the highest Eigenvalue of 5.3 and explained 40.9 % of the total variance. Grouping of the variables within the newly calculated factors showed mainly the same patterns as found above within the self supporting vegetation. Only slight differences occurred in Factor 2 (17.5 % of total variance), where Mg also was included, and in Factor 4 (8.1 % of total variance), where the loading of potassium was substantially lower than in Factor 4 of the supporters. The explained percentage of the total variance in Factor 3 was 11.7 %.

Table 23: The climbers Eigenvalues, percentage of total Variance and factor loadings of the

PCA after Varimax normalized rotation. (Marked loadings are > 0.7; The arrow à marks the second highest loading in Factor 4)

Factor 1 Factor 2 Factor 3 Factor 4 Eigenvalue 5.32 2.27 1.52 1.05 % total Variance 40.9 17.5 11.7 8.1 Altitude a.s.l. 0.901 -0.168 -0.093 -0.025

PFDrel 0.902 -0.197 0.029 0.089 LMA 0.808 0.040 0.462 0.215 C [%] 0.466 -0.375 0.268 0.080

Carea 0.817 -0.018 0.463 0.214

Nmass 0.049 -0.163 -0.876 -0.300

Narea 0.940 -0.051 -0.030 0.015 P -0.172 0.080 -0.834 0.194

K -0.483 0.463 -0.293 à 0.390 Ca 0.260 0.818 0.181 -0.180 Mg -0.243 0.834 0.105 0.138 Mn -0.238 0.710 -0.128 -0.159 Al -0.238 0.166 -0.089 -0.820

Results 71

3.5.1. FACTOR LOADINGS ACCORDING TO THE GENERA

The factor values indicate the reaction of the genus on the variables included in the single factor. (For variable values according to genera also see chapter 3.3.3.)

Loadings of Factor 1 were different between the genera of both growth forms (Fig. 30). Asclepias, Banister, Dioscorea and Smilax had the highest positive values within the climbers. These genera were collected mainly on the upper plots. Strong negative loadings were calculated for the climber genera Cissus, Gonionanthela and Orthaea from the dark plots of lower altitudes. This corresponds with the high factor loading of altitude and light in this factor. Within the supporters, highest values were found in Gauteria, Persea and Vaccinium, while Alzatea, Dyctiocarium, Pentacalia and Schefflera, from the lower forest parts, also had the lowest factor values.

Distribution of factor values by Factor 2 nearly was even within the supporters (Fig. 31). For the climbers highest values were evident in the genera Banister, Dioscorea, Gonioanthela and Topobea, with high Ca, Mg and/or Mn values. Chusquea and Myrsine had the strongest negative factor values within the collected climbers, also containing lowest concentrations of the variables included in Factor 2.

Factor values by Factor 3 were distributed uneven in both growth forms (Fig. 32) Many climbers had values between 0 and 1. On the other hand, Bomarea, Chusquea,

Dioscorea and Gonioanthela had strong negative factor values, reflecting the high Nmass and P leaf contents of these genera. Most of the collected supporter genera had also factor values between 0 and 1. The exception genus Dictyocarium with its high content of Nmass and P showed strong negative values.

The factor values of both growth forms were distributed quite even concerning Factor 4 (Fig. 33). Exceptions within the climbers were the genera Chusquea and Cissus and the genera Macrocarpea and Miconia within the supporters. These plants showed remarkable negative values. The leaves of the self supporting Macrocarpea were high in Al and K content, while the exceptional factor values of the other mentioned genera mainly reflected their high Al contents.

Results 72

3

Mean+SD Mean-SD 2 Mean Outliers Extremes 1

0 Factor 1 -1

-2 ? Cissus Smilax Mikania Myrsine Orthaea Banister Topobea Bomarea Asclepias Dioscorea Chusquea Pentacalia

Gonioanthela 3 Mean+SD Mean-SD 2 Mean Outliers Extremes 1

0

Factor 1 -1

-2 ? Clusia Befaria Persea Alzatea Miconia Myrsine Eugenia Gauteria Purdiaea Baccharis Schefflera Vaccinium Pentacalia Cybianthus Graffenrieda Weinmannia Dictyocarium Macrocarpaea

Figure 30: The factor loadings of Factor 1 among the collected plant genera. (Solid boxes are supporters, open boxes the climbers)

Results 73

5 Mean+SD 4 Mean-SD Mean 3 Outliers Extremes 2

1

0 Factor 2

-1

-2 ? Cissus Smilax Mikania Myrsine Orthaea Banister Topobea Bomarea Asclepias Dioscorea Chusquea Pentacalia

Gonioanthela 5 Mean+SD 4 Mean-SD Mean Outliers 3 Extremes

2

1

0 Factor 2

-1

-2 ? Clusia Befaria Persea Alzatea Miconia Myrsine Eugenia Gauteria Purdiaea Baccharis Schefflera Vaccinium Pentacalia Cybianthus Graffenrieda Weinmannia Dictyocarium Macrocarpea

Figure 31: The factor loadings of Factor 2 among the collected plant genera. (Solid boxes are supporters, open boxes the climbers)

Results 74

2

1

0

-1

-2 Mean+SD -3 Mean-SD

Factor 3 Mean -4 Outliers Extremes -5 ? Cissus Smilax Mikania Myrsine Orthaea Banister Topobea Bomarea Asclepias Dioscorea Chusquea Pentacalia

Gonioanthela 2

1

0

-1

-2 Mean+SD -3 Mean-SD

Factor 3 Mean Outliers -4 Extremes

-5 ? Clusia Befaria Persea Alzatea Miconia Myrsine Eugenia Gauteria Purdiaea Baccharis Schefflera Vaccinium Pentacalia Cybianthus Graffenrieda Weinmannia Dictyocarium Macrocarpea

Figure 32: The factor loadings of Factor 3 among the collected plant genera. (Solid boxes are supporters, open boxes the climbers)

Results 75

2

1

0

-1

-2

-3

-4 Mean+SD Mean-SD

Factor 4 -5 Mean Outliers -6 Extremes -7 ? Cissus Smilax Mikania Myrsine Orthaea Banister Topobea Bomarea Asclepias Dioscorea Chusquea Pentacalia

Gonioanthela 2

1

0

-1

-2

-3 Mean+SD -4 Mean-SD

Factor 4 -5 Mean Outliers -6 Extremes

-7 ? Clusia Befaria Persea Alzatea Miconia Myrsine Eugenia Gauteria Purdiaea Baccharis Schefflera Vaccinium Pentacalia Cybianthus Graffenrieda Weinmannia Dictyocarium Macrocarpea

Figure 33: The factor loadings of Factor 4 among the collected plant genera. (Solid boxes are supporters, open boxes the climbers)

Results 76

3.6. COMPARISON OF YOUNG AND MATURE LEAVES

3.6.1. COLLECTED LEAF SAMPLES

To compare the mature leaf material with leaves that had recently emerged after budbreak, young leaves were taken if available from plants that were collected for the studies above (Tab. 24). All young leaves were treated same way as mature leaves, already described above in chapter 2.6. Plant material for the comparison was sampled from both growth forms on all investigation plots. Apart from OF plot, less climbers than trees carried young leaves on most plots. No increase of abundance on any specific plot was noticeable, neither under extreme sunny nor under shady conditions (Tab. 24).

Table 24: Number of collected plant pairs with young and mature leaves per plot, total and number of collected families.

OF DF BF PF KF MF I MF II PA Total

Climbers 4 3 1 1 1 1 3 2 16

Trees 2 7 6 1 2 3 5 3 29

Table 25 gives an overview of the family composition, where young leaves were found on the collected branches. Sample distribution among the families was widespread. Young leaves were collected on plants of 7 different families, out of the total sampling of 13 families. Out of the total of 15 tree families, young leaves were collected from plants of 12 different families.

Table 25: Number of collected plant pairs with young and mature leaves per plot, total and number of collected families.

Families (n collected) Total

Climbers Alstomeriacea (2), Asclepiadaceae (1), Asteraceae (4), 7 (13) Dioscoraceae (1), Ericaceae (1), Malpighiaceae (3), Liliaceae (4) Trees Alzateaceae (1), Araliaceae (2), Asteraceae (3), Caprifoliaceae 12 (15) (1), Clusiaceae (5), Cyrillaceae (1), Ericaceae (3), Gentianaceae (1), Lauraceae (4), Melastomataceae (4), Rubiaceae (1), n.i. (3)

Results 77

3.6.2. DIFFERENCES IN LMA, Nmass AND Narea

Leaf mass per unit area (LMA) of climbers was generally lower than of the self supporting vegetation (Fig. 34). In both growth forms LMA was lower in young leaves. Mature climber leaves had nearly the same LMA as young tree leaves. Young leaves of both growth forms had about one third less LMA values than mature leaves; 63.3/100.7 g m-2 and 103.1/160.8 g m-2 for young/mature leaves of climbers and trees, respectively.

250

Mean+SD Mean-SD Mean+SE 200 Mean-SE 160.8 Mean

150 ] -2

100.7 103.1 100

LMA [g m 63.3

50

p < 0.01 p < 0.01

0 mature young mature young Climber Tree

Figure 34: Differences in leaf mass per unit area (LMA) between young and mature leaves of both growth forms.

Figure 35 displays the differences in mass based nitrogen content (Nmass) between mature and young leaves of both growth forms. Nmass in fully expanded leaves of the self supporting vegetation was significantly lower than of the climbers. Young tree leaves showed values of the same range of Nmass as both age types of climber leaves and did not differ significantly from the young climber leaves. Young and mature climber leaves showed no differences in Nmass, while the young tree leaves had significantly higher nitrogen contents than the full developed ones. Mean Nmass content in young climber

-1 -1 leaves was 18.70 mg g and 16.38 mg g in the mature ones. Trees had Nmass contents of 16.38 mg g-1 and 11.15 mg g-1 in their young and old leaves, respectively.

Results 78

30

Mean+SD Mean-SD 25 Mean+SE Mean-SE 18.70 Mean

20 16.38 16.38 ] -1

15

[mg g 11.15

MASS 10 N

5

n.s. p < 0.01 0 mature young mature young Climber Tree

Figure 35: Mass based nitrogen (Nmass) of young and mature tree leaves.

Mature climber leaves did not differ in area based nitrogen content (Narea) from mature tree leaves (Fig. 36). The young leaves of the climbers were slightly lower in Narea

(p = 0.09) than the young leaves of the trees. Narea was significantly lower in the young climber leaves than in the fully developed. Mean Narea contents in the young and mature climber leaves were 1126.9 g m-2 and 1601.5 g m-2, respectively. Within the self supporting vegetation Narea remained during leaf aging on a comparable high level, which was still slightly higher than in the mature climber leaves. Mean Narea contents in the young and mature tree leaves were 1713.0 g m-2 and 1698.9 g m-2, respectively.

These results indicate different allocation patterns for some nutrients in the leaf development of the two growth forms. In the investigated case this was evident for nitrogen. Trees had already maximum nitrogen content in young leaves, getting dispersed along the increasing leaf area with advancing leaf age. Climbers on the other hand allocated the nitrogen into their leaf compounds with time delay during leaf maturing, reflected by the increase in Narea from young to fully developed leaves.

Results 79

3000 Mean+SD Mean-SD 2500 Mean+SE Mean-SE Mean 2000 1713.0 1698.9 1601.5 ] -2 1500 1126.9 [g m

area 1000 N

500

p < 0.01 n.s. 0 mature young mature young Climber Tree

Figure 36: Area based nitrogen (Narea) of young and mature climber leaves.

Discussion 80

4. DISCUSSION

4.1. PLOT SELECTION

Tropical montane rain forests are generally characterised by a huge diversity in species and therefore also in structural components (Henderson et al. 1991). Being the same also for the ECSF forest, the selected plots along the mountain slope represented a wide range of different typical forest structures of the Mountain “Las Antennas”. Paulsch (2001) distinguished 14 different structural forest types in his work at the ECSF. Different abiotic factors like altitude, temperature gradient (correlating to elevation), steepness, soil fertility and wind speed at the ridges drive the establishment of species. So the forest types on different sites along the investigated altitudes between 1930 and 2700 m a.s.l. get determined (see also Bussmann 2001). The forest canopy opened with increasing altitude, reflected by increasing gap fraction

(DIFNa) and relative photon flux density (PFDrel), while leaf area index above the investigated plants (LAIa) on the other hand decreased. PFDrel and LAIa from ECSF were situated within the data ranges of four other ecosystems investigated by our workgroup (see also Table 26, Kazda & Salzer 2000 and Kazda & Mehltreter 2001). The measured values of total PFDrel and total LAIt corresponded with given literature data for rainforest systems. Chazdon & Fetcher (1984) reported extremely low PFDrel values between 0.005 and 0.038 on the forest floors of different rainforests. For tropical lowland forests total leaf area indices between 6 and 16 were reported, with LAI of 8 as mean value (e.g. Larcher 1994). Montane rain forests have mostly microphyllic-leaved canopies with heights of

10 m or even less (Whitmore 1998). Consequently this led to the lower LAIt values measured in this study, especially in higher altitudes where open “Elfin”-forest-like structures began to dominate.

The displayed LAIa and PFDrel values of 0 and 1, respectively, in Table 26 from Gabon and Madagascar resulted from the methodical approach. These full light samples were collected from the outer canopy, using the canopy raft equipment for access. High PFDrel values and low LAIa in two plots of the ECSF were not obtained from the uppermost canopy, but nevertheless a comparison with the data from Gabon and Madagascar is partly possible as microclimatic conditions in the crown under open sky are quite often the same as on dry open ground, for example on a clearing (Whitmore 1998). The work in Argentina was carried out in a sand dune system, only collecting samples from the top of Discussion 81 shrubs – which provided data again comparable to an open canopy sampling. Data from South-Germany were collected in two differently shaded understorey plots and one plot on a large clearing. The dark plots of the ECSF showed comparable low PFDrel values with those from Gabon and Madagascar, although the maximum crown closure above the sampled plants, expressed by LAIa, was different on the three sites.

Table 26: A comparison of PFDrel and LAIa value ranges between different investigated ecosystems. (Mean values of the plots; Gabon-data: Kazda & Salzer 2000, Madagascar-data: Kazda et. al 2003, Argentina-data: Kazda & Mehltreter 2001, Germany-data: unpublished)

ECSF Gabon Madagascar Argentina S.-Germany Neotrop. montane African lowland Coastal lowland Subtropical sand European rain forest rain forest rain forest dune vegetation deciduous forest

No. of sites 8 4 3 4 3

PFDrel 0.02 – 0.98 0.01 - 1 0.03 - 1 full PFD 0.12 – 0.73

LAIa 0.1 – 5.3 0 – 6.4 0 – 4.4 open 0.5 - 3.1

4.2. ASSOCIATIONS BETWEEN CLIMBERS AND HOST PLANTS

Many relationships between the different growth forms can be expected in the network of trees, shrubs and climbers of a tropical forest. Campbell & Newberry (1993) studied the associations between lianas and trees of the most common 12 families and 16 species in a lowland forest in East Malaysia. Among most families, lianas were highly aggregated on individual trees. For Dipterocarpaceae hosts, the number of lianas per tree followed a negative binomial distribution, leading to high aggregation rates. Despite their higher mean number of lianas per tree the family of Euphorbiaceae had a lower aggregation rate. Based on natural tree species abundances, Carse et al. (2000) reported from a Bolivian dry forest significantly lower liana colonisation rates than expected on the supporters Anadenanthera colubrina Brenan and Attalea phalerata Mart., whereas Neea hermaphrodita S. Moore had significantly more liana-colonized individuals than expected. These results were confirmed by Muthuramkumar & Parthasarathy (2001) and Chittibabu & Parthasarathy (2001) in India, as Dipterocarpaceae and Clusiaceae again fitted better to a negative binomial model than trees from the families Euphorbiaceae and Meliaceae. In this tropical evergreen forest system, lianas were distributed Discussion 82 inhomogeneously among their host tree species. Phoebe wightii Meissn. and Neolitsea scrobiculata Gamble supported significantly smaller number of lianas, while Beilschmieda gemmiflora Kosterm. hosted a greater number than expected. Different characteristics of the supporters, like bark texture, shading of branches or bole diameter (see Introduction for a more detailed overview), drive these distribution patterns of climbers. Purpose of this study was to examine differences between climbers and their supporters, not to give complete species diversity information about the ECSF forest. Therefore only self supporting vegetation infested with climbers was collected. In most cases only one climber was associated with its host. Although sampling was focused on these 1:1 pairs, most hosts in this forest tended to support only one climber. Liana richness was poor as big woody lianas reach their limit of occurrence in this altitudes (Schmitt 2003). Many small and non woody climbers especially grow in the understorey. This seems to be a general distribution pattern for montane forests compared with the lowlands. Huge loads of epiphytic plants on the tree branches, especially in the more open sites, might impede the establishment of large lianas in humid montane forests. Grubb et al. (1963) compared a primary lowland forest in amazonian Ecuador with a montane forest plot in the Andes. Many small dicotyledone understorey climbers were abundant in higher altitudes, while the lowland forest contained more big lianas, climbing up to the tree crowns. In the lowland of Yasuní, Ecuador, woody lianas contributed substantially to the plant diversity in this forest, too (Nabe-Nielsen 2001). Even non-woody small climbers can play a substantial role as connecting elements in the vegetation, particularly in montane forests (Grubb et al. 1963, Finckh & Paulsch 1995, Stern 1995 and Laurance et al. 2001). As only a small part of the entire tree and climber composition could be investigated within this study, a detailed report about the associations between the two growth forms was not possible. Instead, the associations between single plant genera were tested. In a former study on sand dune vegetation on the subtropical island of Martin Garcia (Argentina) associations between the climber Smilax campestris Griseb. and the supporter Celtis tala Gill. ex Planch were found to be evident, while the most dominant liana Serjania meridionalis Cambess. was abundant on all supporting species (Kazda & Mehltreter 2001). As distribution of the different plant species was not even among the investigation plots at the ECSF, a comparable result was expected in this forest as well. Low numbers of single species samples required a testing on genus level for the three climber species mainly collected, but no significant associations with specific hosts have Discussion 83 been found. So further work on the differences between the two growth forms was not affected by any aggregations.

4.3. DIFFERENCES IN LEAF STRUCTURE AND NUTRIENT ALLOCATION

4.3.1. REDUCTION IN LEAF MASS PER UNIT AREA IN THE CLIMBERS

Climbers are well known for their reduction in supporting tissues on stem and branch basis. This reduction also continues on leaf level (Putz 1983, Castellanos et al. 1989, Cornelissen et al. 1996) as climbers have lower leaf mass per unit area (LMA). The former studies of our workgroup, displayed in Table 27, confirmed these findings. Investigating always two linked plants as a climber/host-pair gave the possibility to achieve concrete data for a comparison of both growth forms.

Table 27: A comparison of LMA value ranges between different investigated ecosystems. Climbers and supporters differed significantly on all sites. (Mean values of all collected plants)

-2 LMA [g m ] ECSF Gabon Madagascar Argentina S.-Germany

Climbers 93.5 68.2 98.9 75.0 39.9

Supporters 163.4 97.9 176.4 124.0 49.0

p < 0.01 0.01 0.01 0.01 0.01

Low LMA can help lianas to reduce their load on the hosts (Kazda et al. 2003). A breakdown of supporting branches would destroy the whole system and either kill the climber or result in new investments. With reduced LMA, the climbers get the advantage to build up quickly a large area of photosynthetic tissue that shades the host tree, with relatively low investment costs. The liana Combretum fructicosum is known to reach 95 % of its maximum leaf area within one month, while trees from the same forest in Panama mostly needed six times longer for their full leaf area expansion (Avalos et al. 1999). Shading effect on host trees by liana is strong as their leaf transmittance was reported to be more or less 30 % lower than that by tree leaves (Avalos et al. 1999). As climbers can only carry few leaves on their structure-poor branches (Givnish & Vermeij 1976), this effective light absorption system accompanied with low self-shading gets important when Discussion 84 they acquire the same space as their hosts. In Madagascar (Kazda et al. 2003) and in Costa Rica (Heinen 2003) the climbers had lower leaf area densities (leaf area per crown volume) than the self supporting vegetation. Leaf development is much slower for species with larger LMA as more resources are needed for construction of supporting leaf tissue (Miyazawa et al 1998). Together with the fast stem growth of the climbers and the resulting enhanced space conquest, this factors lead to principal competitive advantages over the hosting trees. Longevity of the leaves might change the pay-off, as plants with low LMA are reported to have a shorter leaf life-span (Mulkey et al. 1995, Reich et al 1991, Reich et al 1999). But even in the temperate deciduous forest on the South Germany site, where the leaves of Clematis vitalba remained on the plant as long as the leaves of its supporters, LMA was still significantly lower within the climbers. According to Villar & Merino (2001) leaf construction costs have a strong correlation with LMA. When comparing the leaf construction costs of plants with different leaf life-spans, no differences were found as soon as LMA was included as covariate – so LMA seems to be more important than leaf life-span when to determine differences in the carbon balance between species (Villar & Merino 2001). A prolonged maturation period of leaves can result in physiologically undeveloped leaves at the time of full leaf area expansion (Miyazawa et al 1998), while fast built leaves already achieve full carbon gain. For the liana Clematis vitalba L. van Bebber (1998) reported high chlorophyll contents in the very beginning of the vegetation period. Young leaves of kiwifruit vines have been shown to achieve remarkable rates of photosynthesis already 10 days after budbreak, a long time before full leaf expansion (Greer 1996). Accordingly a longer leaf life-span does not necessarily result in photosynthetic advantages (as generally stated, e. g. by Coley et al. 1985 or Gulmon & Mooney 1986) For a tropical vine from the Araceae family Ackerly (1992) reported mean LMA values of 31 g m-2. On the ECSF site, LMA was extremely high in the collected plants of both growth forms - even higher than on the nutrient poor sand dune sites in Argentina, where leaf longevity is generally high. Severe climatic conditions in montane rain forests lead to microphyllic, xeromophic, and therefore heavy leaf structures (Whitmore 1998). This was not only valid for trees, but also for climbers on a lower level. In Madagascar the collected leaves also had a very high LMA, but there more than 50 % of the leaves were sampled from the outer canopy, while the ECSF collection proceeded over a wide range of plots with lots more different radiation intensities.

Discussion 85

4.3.2. LEAF STRUCTURE ON DIFFERENT PLOTS UNDER CHANGING LIGHT REGIMES

Mean area of a single leaf (LA) of the climbers was generally lower than of their host trees. This result was inconsistent with the hypothesis of Givnish & Vermeij (1976) in which they principally predicted larger leaves with long petioles in lower number for climbing plants as a response to economical savings. Reasons for this result might be found in the adaptations to irradiance and moisture. These adaptations will be discussed later in this chapter. A slightly negative correlation between PFDrel and LA only was evident for the self supporting vegetation. Trees had leaf sizes of a wide variability, while the climbers leaves had an obviously smaller range and were more consistent in leaf size among the specimens.

Table 28: LMA of both growth forms under two extreme light conditions on the different study sites, respectively. (Mean values of all collected plants)

-2 LMA [g m ] ECSF Gabon Madagascar Argentina S.-Germany PFD Shade Sun Shade Sun Shade Sun Shade Sun Shade Sun

Climbers 56.2 136.7 51.0 116.0 59.2 133.2 - 75.0 26.6 56.1

Supporters 102.1 255.8 76.0 147.7 88.7 252.3 - 124.0 34.0 68.7

p < 0.01 0.01 0.01 0.05 0.01 0.01 0.01 0.01 n.s.

High leaf masses per unit area (LMA) were characteristic for the plants of the upper open plots (KF, MF I&II, PA), while the leaves from the other plots had substantially lower values. Compared with the investigated sites in other ecosystems, LMA under different light regimes was generally high in this study (see Tab. 28, Kazda & Salzer 2000 and Kazda & Mehltreter 2001). Only the data from Madagascar were also that high. Extreme abiotic conditions and high radiation combined with strong winds can lead to drought situations if clouds are absent. This might be one driving factor in these two ecosystems, but more likely the conspicuously high LMA findings are a result of scleromophology, induced by nutrient poorness (Chapin 1980, Fonseca et. al 2000, Wright et. al. 2002). Occasional frosts, occurring in the upper regions of the Mountain “Las Antennas”, may also contribute to the scleromorphic leaf structures on the PA plot. The relatively low values from Germany correspond with data of Abrams & Mostoller (1995), derived from tree saplings in a Pennsylvanian oak forest of different successional status. Discussion 86

Because of former human impacts on the OF plot, the vegetation here was in an early successional status. Pioneer plants are famous for their fast growth rates, which can consequently lead to low LMA. OF also was the only investigated plot with no significant differences in LMA between the two growth forms, which confirms the hypothesis of Bazzaz (1979) that early successional plants generally show a wider range of phenotypic responses (see also Bazzaz & Carlson 1982 and Teskey & Shrestha 1985). In this case it results in a higher standard deviation, diminishing the statistical power of the differences. On all other plots LMA always was significantly lower for the climbers. Concerning the single plots more significant differences were found within the climbers, which indicates their enhanced adaptation to the prevailing conditions. Within the changing light conditions, plants from the darkest investigation plots had leaves with lower

LMA than plants collected from plots with high PFDrel values above the sample pairs. This result corresponds with the findings of many former studies (e.g. Jackson 1967, Abrams & Mostoller 1995, Sims & Pearcy 1994 Chen & Klinka 1997 or Sterck 1999). More biomass in a given exposed leaf area, mainly by extra layers of palisades (Hanson 1917, Björkman 1981) increases the photosynthetic capacity of high-light leaves by an increased number of chloroplasts and the amount of photosynthetic enzymes. On the other hand this leaf architecture also reduces the light capture efficiency under low-light conditions (Evans & Poorter 2001). Thereby thin built leaves with widespread photosynthetic apparatuses and lower CO2 resistances are advantageous (Evans 1999). Response quality to the prevailing light conditions in leaf architecture was not the same for the two growth forms. Under sunny conditions smaller leaves have to be expected as the relation between photosynthetical gain and transpirational cost is best in small leaves (Givnish & Vermeij 1976). This was true for both groups, but the supporters had the tendency to build smaller leaves on the PA plot than the climbers. As small leaf size was mostly found in the family of Ericaceae, their great abundance on this uppermost plot could explain this finding. Under shady conditions a high mean leaf area was to be expected (Whitmore 1998) as light harvesting gets optimised with leaf size. This was only found to be clearly evident within the self supporting vegetation. Climbers invest much biomass toward their explorative leaf-free shoots, especially under shady conditions. Probably this economic factor results in the smaller climber leaf sizes that were measured in this study. The climbers kept their leaf size quite constant within a smaller variation rate than the trees, although especially larger variations in leaf size under shade could have been expected as many abiotic factors have equal influences on this trait Discussion 87

(Givnish & Vermeij 1976). Small variation also was evident for the LMA of the climber species. LMA in both growth forms increased linearly with PFDrel, while over the whole range of radiation the self supporting vegetation had higher LMA values with obviously greater variation. Comparable results were also found in the lowland rainforest of Gabon for the relationship between LAI and LMA (Kazda & Salzer 2000). Expressed on genus- level, the climbers again showed less differences between the single genera than their hosts. Some supporters, especially those collected on the upper plots, were not only responsible for the high mean LMA of this growth form but also had great standard deviation, intensifying the variations in LMA described above. Carbon content, as the main structural component in a leaf, did only differ between the two growth forms on four plots. It was generally higher concentrated in the supporter leaves, and along the altitudinal gradients in the upper plots. When expressing the carbon allocation among the leaf area of the collected plant (Carea), the same patterns were found as for the LMA. Differences between the growth forms were evident on all plots, except on the OF plot. Again there were more significant differences between the single plots within the climbers than within their supporters. Obviously the climbers have a better ability to adapt their leaf structure to the amount of sunlight they acquire. Quick plant growth, fast leaf turnover rates and short leaf longevities (Gentry 1983, Putz & Windsor 1987, Hegarty 1991) enable them to built up leaves with optimal size and biomass investment for each given condition. This result becomes even more evident, when expressing the relationships between LMA and leaf nutrient contents. A fast leaf turnover rate, typical for plants with low LMA, requires much nitrogen and other nutrients for maintenance.

4.3.3. NITROGEN ALLOCATION AND ITS ROLE IN PHOTOSYNTHESIS

Nitrogen plays a major role for photosynthesis and thereby in the carbon balance of the whole plant. The correlation between light-saturated rate of photosynthesis (Amax) and leaf nitrogen was reported to be strong (Mooney et al. 1978, Osmond 1983, Field & Mooney 1986, Ellsworth & Reich 1992) as 50 to 80 % of the leaf nitrogen is allocated in photosynthetic proteins (Makino & Osmond 1991). Nitrogen is a valuable resource, therefore it can be expected that plants optimise the N partitioning towards a maximised photosynthesis (Evans 1989). Under high irradiances large investments of nitrogen enable to construct leaves that are able to assimilate much carbon. On the Discussion 88

opposite, in shade huge nitrogen investments in order to raise Amax would not generally result in higher carbon gain. Thicker chloroplasts are build up under insufficient radiation.

Consequently this leads to a reduced CO2 diffusion rate and decreasing ribulose 1,5- bisphosphate (RuBP) enzyme activity (Evans 1999). When soil nitrogen availability is limited, plants have to use their nitrogen efficiently, building up leaves that are well adapted to the surrounding environmental conditions (Hikosaka & Terashima 1995). With decreasing light availability nitrogen seems to be used for more efficient light harvesting (Niinemets 1995). The given nitrogen per leaf mass then is allocated along leaf area and cell walls to enable still good RuBP carboxylase activity in shade and thereby optimal photosynthetic efficiency, which is more important under such conditions than maximum capacity values (Evans 1998). Correlations between the amount of photosynthetic active radiation (PAR) and leaf nitrogen have been found, which confirms this theory (Field 1983, Hikosaka 1996).

In this study the climbers had significantly higher mass based N contents (Nmass) than their hosting self supporting vegetation. Same results were found on the sites in Gabon and Madagascar (Tab. 29). Reich et al. (1990/1991a) and Abrams & Mostoller (1995) described higher leaf N in early successional plants than in late successional ones, which is consistent with the higher adaptability reported for the first plant type (Bazzaz 1979). This might also be valid for the comparison between climbers and their hosts. The nitrogen content of the ECSF leaf samples was much lower than in the study in

Argentina (Tab. 29), where the two growth forms did not differ in their Nmass (Kazda & Mehltreter 2001). Results from South Germany were comparable with Argentina, indicating that N was not a limiting factor in those two ecosystems. Over all, the samples from the ECSF were at the lower end of the general range of nitrogen content described in literature. Grubb (1977) gives a good overview about foliar element concentrations in different ecosystems (see also Larcher 1994 or Bigelow 1993). Comparable low N contents were described by Tanner (1977) for montane forests on Jamaica. Tropical

-1 Araceae vine leaves had mean Nmass of 28.5 mg g (Ackerly 1992). Mo et al. (2000) reported values between 9.5 and 25.4 mg g-1 in their study about distribution patterns of nutrients in plants of a subtropical broad-leaved forest. In their results, trees had a mean

-1 -1 Nmass of 19.0 mg g , whereas the lianas had only 15.3 mg g . These findings were contradictory to the present studies of our workgroup. Low availability of nitrogen in montane rainforest soils (Bruijnzeel et al. 1993) can explain the differences. The total nitrogen content in upper horizons of the ECSF forest soils was not low (- the organic layer Discussion 89 was on some sites more than 40 cm thick -) and even higher than reported from other montane cloud forests (Steinhard 1979, Edwards 1982), but relatively low decomposition rates in such ecosystems can lead to low levels of mobile nitrogen that is available for the plants. On the other hand, Bigelow (1993) reported substantially higher mass based N contents, especially for the climber genus Smilax than in all investigated tree species. His data from a tropical lowland forest were confirmed by the results from ECSF.

-1 -2 Table 29: A comparison of leaf nitrogen value ranges (N [mg g ] and Narea [g m ]) between different investigated ecosystems. (Mean values of all collected plants)

ECSF Gabon Madagascar Argentina S.-Germany Nitrogen N Narea N Narea N Narea N Narea N Narea

Climbers 15.7 1.38 24.1 1.57 15.8 1.44 26.7 1.95 28.9 1.12

Supporters 12.4 1.84 18.4 1.74 11.7 1.82 26.1 3.10 26.4 1.24

p < 0.01 0.01 0.01 0.05 0.01 0.01 n.s. 0.01 0.01 0.05

Nearly no differences could be found between the single plots in the mass based leaf nitrogen of both growth forms. Within the trees only OF with the higher Nmass values differed from most other plots, indicating that on this clearing the soil nitrogen pool was mobilised by higher temperatures. This explains additionally, why early successional plants were reported to have higher leaf N (Abrams & Mostoller 1995). The findings on the plots along the slope were confirmed by the results of correlation analysis between PFDrel and Nmass where no relationships occurred. Changes in leaf N contents under different light conditions would have been expectable (see above and Ellsworth & Reich 1992), but were not evident. Kazda & Lösch (1992) described N contents of about 20 mg g-1 for canopy leaves of a Cameroon lowland forest, a value even higher than found on ECSF in the high-light tree leaves. Several studies have shown that nitrogen concentration is rather constant or decreases with increasing LMA (Reich et al. 1991), while LMA considerably changes together with light (Hirose & Werger 1994, Hikosaka & Terashima 1995, Niinemets et al. 1998, Evans & Poorter 2001). These results agree match with our findings. Similar N-values under high and low radiances may result when nitrogen is partitioned differently into RuBP carboxylase and chlorophyll by the plant (Evans 1989). Discussion 90

Concerning nitrogen content on leaf area basis (Narea), the climbers had lower contents than their supporters. Narea generally increases with LMA (Ellsworth & Reich 1993, Kull & Niinemets 1993, Reich & Walters 1994). With same mass based N content and lower LMA within the climbers, this result is a logical mathematical consequence. Higher

Narea in climbers than in self supporting vegetation was evident in all of the investigated ecosystems (Tab. 29). The samples from all investigation sites (except for Argentina) had

Narea contents in comparable range. Narea was generally higher than reported by Ackerly -2 (1992) for a tropical vine (0.89 g m ). On the other investigation sites, Narea also increased with rising LMA under high-light conditions and remaining Nmass (Tab. 30). Nitrogen in the thick-build leaves is partitioned mostly into soluble proteins (RuBP carboxylase) to achieve a maximised photosynthetic capacity. Under the influence of shade the LMA declines and nitrogen is mainly allocated toward thylakoid proteins of the photosystem reaction centres to enable best photosynthetic efficiency (Evans 1989).

-2 Table 30: Narea [g m ] under two extreme light conditions on different study sites. (Mean values of all collected plants)

-2 Narea [g m ] ECSF Gabon Madagascar Argentina S.-Germany PFD Shade Sun Shade Sun Shade Sun Shade Sun Shade Sun

Climbers 0.83 2.14 1.12 2.53 1.11 1.72 - 1.95 0.85 1.47

Supporters 1.26 2.19 1.32 2.54 1.21 2.34 - 3.10 0.90 1.55

p < 0.05 n.s. 0.05 n.s. n.s. 0.01 0.01 n.s. n.s.

These mechanisms are generally true for all plants, but every life-form shows a different relationship between CO2 assimilation and Narea (Sage & Pearcy 1987 in Evans 1989). The correlation coefficient on an area basis improves considerably when separating the single life-forms (Field & Mooney 1986). This was also true for the leaf conductance, being quite proportional to the CO2 assimilation rate (Körner et al. 1986). These differences between plant groups should also be true for the basic correlation between Narea and irradiance intensity. The recent study showed that the growth form climber had a higher correlation coefficient for these traits than the self supporting vegetation. The results from Gabon (Kazda & Salzer 2000) agreed with these findings, as the climbers leaf nitrogen (expressed both per unit dry mass and per unit area) was Discussion 91

correlated with leaf area index above the sample pairs (LAIa), while there were no correlations for the host trees.

Lower variations among the Narea values of climber leaves again confirmed the finer adjustment of this growth form to the PFD conditions occurring in their habitat. The differences between climbers and their hosts did not keep constant with changing irradiance. Lower Narea values for the climbers compared with their supporters were found in the shady understorey, underlining the climbers high efficient ratio of investment and light harvesting. This was consistent until the canopy opened completely on the PA plot where both plant groups had the same contents – the same finding as reported in the Gabon study (Kazda & Salzer 2000). Under full light exposition most nitrogen seemed to be intensely invested towards maximum photosynthetic capacity, which resulted in comparable Narea values in both growth forms and can lead to (and explain) identical Amax data, as reported by Castellanos (1991), although higher rates for the climbers might have been expectable due to their lower LMA and faster growth rates. The data from South Germany showed similar nitrogen allocation patterns, while in Madagascar and Argentina under sun the climbers had lower Narea than their hosts. Higher potassium (K) contents in the climber leaves from Argentina explained the findings of this site. (See further details in chapter 4.3.4).

On the three plots of the South German site gas exchange measurements were performed on the liana Clematis vitalba L. and its adjacent supporters in late June and early July 2001. The Amax values derived from this study (Tab. 31) corresponded widely with literature data for temperate forests (see overviews in Castellanos 1991 and Larcher

1994). Van Bebber (1998) only found slightly higher Amax values for Clematis vitalba. No significant differences between climbers and their supporters were observed in the measured light response curves, no matter if concerning photosynthetic capacity on area basis (Amax), on dry mass basis (Amass), or calculating light compensation points (LCP) (Tab. 31). These findings confirmed the results of Castellanos (1991), stating that lianas do not have higher photosynthetic capacities than trees. Higher Amass values under open conditions (although not significant, due to an extremely high standard deviation within the trees) could nevertheless indicate that climbers are able to achieve the same carbon gain with less investments per leaf than trees. Winter et al. (1986) reported for the tropical understorey vine Hoya nicholsoniae a light saturation already at 100 µmol quanta m-2 s-1, Discussion 92 which is outstandingly low compared with data for woody plants, provided in the overview by Larcher (1994). Further data evaluation is necessary to examine whether climber leaves have light saturation points lower than the hosting self supporting vegetation or not. This could add important further information about the low-light adaptability of climbing plants. In tropical as well as in temperate vines low light compensation points had been observed by Carter & Teramura (1988) and by Castellanos (1991). With light compensation points below 20 µmol m-2 s-1, this was evident on the German study site, too. The results from Clematis vitalba by van Bebber (1998) were again comparable with ours. Moreover the investigated self supporting vegetation had very low light compensation points (comparing overview in Larcher 1994).

Table 31: Mean values for Amax, Amass and the LCP in climbers and their supporters growing under different light conditions in a South German temperate forest.

-2 -1 -1 -1 -2 -1 Amax [µmol CO2 m s ] Amass [µmol CO2 g s ] LCP [µmol quanta m s ]

Environment Total Shade Sun Total Shade Sun Total Shade Sun

Climbers 9.0 6.4 11.4 0.24 0.24 0.21 13.2 12.1 11.4

Supporters 9.2 8.3 9.1 0.21 0.24 0.15 16.9 11.5 9.1

p < n.s. n.s. n.s. n.s. n.s. n.s. n.s. n.s. n.s.

Climbers are able to adapt their photosynthesis system very quickly to changing light conditions (Avalos & Mulkey 1999). While the self supporting vegetation generally has to produce a new generation of leaves to cope with changing conditions, climbers are reported to have the ability to change their physiological leaf type within the lifespan of a single leaf generation (Avalos, pers. comm.), which obviously can save remarkable amounts of carbon. This adds to other competitive advantages climbers already possess due to their economical savings reported above. Furthermore Osmond (1983) described strong relationships between nitrogen supply and photosynthetic acclimation potential of plants according to the irradiance level during growth. In addition to the generally high values of leaf nitrogen content in climbers, this could explain their conspicuously high abundance on sites with high nutrient availability, for example forest edges or disturbance gaps.

Discussion 93

4.3.4. THE OTHER NUTRIENTS

Phosphorus is a major element in plant metabolism and the synthesis of ATP during photosynthesis. It was generally lower concentrated in leaves that were collected during this study than reported by Cornelissen et al (1997) for woody plants from temperate western Europe or Bigelow (1993) for a tropical lowland forest at La Selva (Costa Rica). Additionally the samples of these two studies were much higher in nitrogen content and had a lower LMA, indicating a better nutrient supply on those sites. Mean foliar P concentrations, given for a lowland subtropical forest by Mo et al. (2000), for an African lowland forest canopy by Kazda & Lösch (1992) and for montane forests by Tanner (1977) correspond much better with the findings from the ECSF. On all plots climbers had higher P concentrations in their leaves than their supporters. This confirmed the results of Cornelissen et al. (1997), while Bigelow (1993) and Mo et al. (2000) did not state any significant differences between the two growth forms. When expressing the P content on area basis (not shown), the climbers from the ECSF had lower values than the self supporting vegetation, which corresponded well with the findings of Bigelow (1993). Differences between the single plots were mainly found just between OF plot and the other plots, where the P concentrations were significantly lower. This result confirmed that more nutrients get mobilized on disturbed sites. The climbing genus Valeriana and the self supporting genera Ageratina, Dictyocarium and Piper were typical samples, as all of them were collected on the OF plot (or nearby in the case of Dictyocarium) and showed higher concentrations than the other genera.

Potassium was another nutrition element that differed in its concentration between the two growth forms. K concentration in the leaves was up to four times higher than reported for the canopy of the lowland forest in Cameroon (Kazda & Lösch 1992). Values given for montane tropics by Tanner (1977) and the data in Mo et al. (2000) are only slightly lower. In the later study no differences between the growth forms occurred, while in the study of Cornelissen et al. (1997) lianas again had a higher mean K content in their leaves than trees. The data from Cornelissen et al. (1997) were comparable with the findings on ECSF. Here the climbers generally stored more K (per mass dry weight) in their leaves than their supporters, too. Leaf K was distributed quite uneven among the investigated plots and the highest values were found on the dark DF plot (with a significant negative regression along PFDrel within the climbers), although the concentration in the soil did not increase Discussion 94 remarkably. This result could not be explained by any accumulating genus. As crown closure was higher above the sampled leaves of the DF plot than on all other investigated ECSF plots, high leaf K probably was a result of lower K leaching rates. Comparing the single plots, more differences within the climbers were found, but again all regarding the DF plot. The ECSF results were comparable with data from the Argentina site (Kazda & Mehltreter 2001), and thereby indicate a better drought adaptability for the climbers. Although the ECSF is covered most time of the year with clouds and mist, providing enough water for the plants, the dry season “veranillo” around December might lead to heavy drought situations, as many days without precipitation follow in line. Freiberg & Turton (2003) reported that comparable situations had large effect on plant survival in tropical Australia. In Argentina different potassium (K) contents in the two growth forms counterbalanced the principal advantages of thickly built supporter leaves with increased Narea contents under high irradiances. There, the climber samples had significantly higher K values (Kazda & Mehltreter 2001), which enabled them a better adaptation to drought situations, as potassium plays a great role in stomatal regulation and as a osmotic solute (Finck 1969, Marschner 1995). Thereby climbers can save carbon by producing leaves of lower scleromorphy, even in such dry environments. This was also true for the sandy site on Madagascar, as the evaluation of potassium data from there were has shown (Kazda et al. 2003). In combination with the higher irradiances on the upper ECSF plots, higher concentrations would have been expectable, but were not evident. Lower temperatures in this altitude and also substantial amounts of dew on the leaves might counterbalance drought that would be induced by strong winds and radiation. Nevertheless a higher K concentration generally is advantageous for climbers. It can get necessary for their flexibility to respond quickly to changing conditions during fast plant development through a patchy understorey, where drought situations can occur suddenly.

Both growth forms did not differ in their contents of Calcium and Magnesium that antagonistically regulate tissue-swelling . Both nutrients had the same concentration range as found in leaves from the canopy of Cameroon lowland forest (Kazda & Lösch 1992). Compared with the data of Tanner (1977) the Ca and Mg concentrations were nearly similar, too. Mg contents were comparable with the concentrations in samples from the Argentina site (Kazda & Mehltreter 2001). On the other hand Ca was much Discussion 95 higher concentrated in Argentina leaves (Kazda & Mehltreter 2001), which is typical for plants growing on dry subtropical soils (Larcher 1994). In the study of Mo et al. (2000) Ca was only slightly higher concentrated than in leaves from the ECSF study site, but on the other hand Mg concentration was nearly three times lower. Differences between self supporting vegetation and lianas were not evident in the work of Mo et al. (2000), but in Argentina significantly lower Ca concentrations in the climber leaves were found. Ca and Mg concentrations were quite similar among all sampled genera. Leaf Mg content decreased significantly with increasing PFDrel within the collected climbers, but not that strong within their hosts. This corresponds well with the findings of Niinemets (1995) in which a negative correlation between LMA and Mg was reported. Demand for Mg is high for chlorophyll construction as these two factors correlate strongly (Schulze & Küppers 1985), and this demand increases with decreasing LMA and PFDrel. Although there was no general difference in leaf Mg between climbers and their hosts, the enhanced adaptation towards higher chlorophyll content in shade by higher Mg content is obvious and enables the climbers to adjust well to such conditions.

Manganese, which is important for photosynthesis and transfer of Phosphate, lay in about the same concentration range as the values reported from the canopy in Cameroon (Kazda & Lösch 1992). Compared with the data of Tanner (1977), Mn leaf concentration was nearly three times higher in the recent study. Mn values were not investigated by Mo et al. (2000). Although Mn values generally did not differ between the growth forms, a significantly higher concentration in the supporters was found on the ECSF plot PA. Mn was distributed very uneven among the plots. Wilcke et al. (2002) reported an extreme patchiness of available nutrients for plant growth in the heterogeneous soils of the slopes of the Mountain “Las Antennas”, which might be reflected in this patterns. Uneven Mn distribution was evident within the genera of both growth forms. The highest Mn contents were found in leaves of specimens that were collected on plots with high irradiance values. Probably, these specimens tend to accumulate Mn.

4.3.5. THE ROLE OF ALUMINIUM

On the investigation plots soil pH was very low, comparable with some of the lowest values reported by Wilcke et al. (2001) for this forest. Therefore increased Al concentrations in the soil were expectable, and were also reflected by the contents in Discussion 96 the sampled leaves. Especially in the supporters mean leaf concentration of Al was much higher than the concentrations found in the canopy study of Kazda & Lösch (1992). Aluminium toxicity is known to be one of the most important factors limiting plant growth on acid soils (Darkó et al. 2002). Ca/Al-ratio in the soil lower than 0.1 on molar basis, as found in the mineral soils of most plots (see Appendix 2), influences root growth negatively. Main impacts for the plant on root base are an inhibited growth of fine roots and root tips as Al accumulates in the cell walls and leads there to an increased crystallinity by disturbing the pectin matrix (Horst et al. 1999, Schmohl & Horst 2001). Severe injuries on the root surface get common in this case (Budikova 1999, Matsumoto 2000, Schildknecht & Vidal 2002). On leaf level a decrease in net photosynthesis (A) was reported by Pereira et al. (2000) as Al reduces the photochemical efficiency of the photosystem II (Moustakas et al. 1993, Moustakas & Ouzounidou 1994). With rising transpiration rates (E) and lower A, water use becomes less effective (Ohki 1986). Besides, ATP concentration in the leaves decreases (Loren-Plucinska & Ziegler 1996) and damages of the chloroplast and its membranes occur (Hampp & Schnabl 1975, Moustakas et al. 1997, Pereira et al. 2000). Plants can response to high Al loadings in the soil by excluding the aluminium, which is possible by alkalising their rhizosphere to diminish Al-mobility (Lüttge 1997). An other way is to store Al in a chelatised form inside the vacuoles of the cells (Lüttge 1997). Organic acids and especially citric acid play the most important role (Naumann & Horst 2000, Ma et al. 1997). Among trees in a Venezuelan cloud forest Cuenca et al. (1990) found both Al-accumulators and Al-excluders. As on all ECSF plots the mean Al content in leaves of supporters was higher than in the climbers, one can presume that the self supporting vegetation had more tendencies towards the first adaptation method. Only the climbing genus Muehlenbeckia from OF plot seemed to accumulate aluminium in its leaves (0.47 mg g-1; average: 0.07 mg g-1). Most climbers with their light-built leaves might not be able to store the Al-chelat-complexes as their vacuole volume might not be sufficient. Excluding the toxic element might therefore be more economic for this growth form. When exclusion is impossible, fast leaf turnover rates might help the climbing plants to get rid of the slowly accumulated aluminium. By assuming a lower Al-adaptability within climbing plant, this could also explain the lower abundance of big lianas on this site. Leaf Al concentration was found to very vary much between some plots, especially within the trees. This was causally related with some self supporting genera that were found to accumulate Al. The genera Graffenrieda and Miconia, both from the Melastomataceae family, made up two of these three plant host Discussion 97 genera (leaf Al-content: 4.1 – 9.5 mg g-1). Haridasan (1982) and Lüttge (1997) also reported extremely high Al concentrations of up to 66100 ppm in the xylem sap of some Al-accumulating Melastomataceae species growing in a cerrado – at an average Al- level of 910 ppm in the vegetation. Soil Al was on some plots higher in the organic matter than in the mineral soil. This can be explained by relatively high concentrations of Al in the fallen leaves and low decomposition rates on the sites, also leading to the huge layers of organic material that were found in some parts of the forest.

4.3.6. CLASSIFICATION DERIVED BY PCA

The application of a Principal Components Analysis (PCA) on a dataset with many variables helps to reduce redundancies between the single variables. New factors are derived that include all variables that are highly correlated (McGarigal et al. 2000). Several recent ecological studies of different scientific fields use this statistical technique to reduce the size of their dataset and find new patterns (see e.g. Schowalter & Ganio 1998, Webb & Peart 2000, Van Buskirk & Saxter 2001 or Logan et al. 2001). Alonso & Herrera (2001) used a PCA to test if the structure of covariation between leaf macronutrients was the same in different plant populations. Like Hobbie & Gough (2002) they assumed that in leaves several nutrients have such strong correlations that they can be summarized to a lower number of new factors. Earlier studies by Garten 1976, Garten 1978, Duarte 1992 or by Thompson et al. 1997 indicated several non-randomly covariations between different nutrients across plant species and supported the basis for that idea. In this study, additional parameters of the dataset from the ECSF were added to investigate the relationships between external and internal parameters and how they can characterise leaf parameters. Results were nearly the same for both growth forms. As expected, strong correlations between altitude, relative photon flux density (PFDrel) and the specific leaf mass (LMA) were found, as these parameters are generally highly linked in nature. Therefore these parameters were combined in the new Factor 1. On the study site crown closure decreased with increasing altitude, which leads to higher PFDrel values at understorey plants. LMA was positively correlated with PFDrel. The elements nitrogen and carbon also contributed to this first factor when expressed on leaf area basis (Narea and

Carea, respectively). The impact of LMA played the most important role. The second factor (Factor 2) was derived from manganese (Mn) and calcium (Ca), both positively Discussion 98 correlated as expected according to Alonso & Herrera (2001). Magnesium (Mg) is known to be an antagonist of Ca and a synergist of Mn (Larcher 1994) and should normally be positively associated with them (Garten 1976, Garten 1978). In the sampled leaves of this study Mg was only found to be positively correlated with Mn and Ca, having a high factor loading in Factor 2 within the climbers. Mass based nitrogen (Nmass) and phosphorus (P) were grouped towards Factor 3 by the PCA. Both elements mainly control the plants photosynthesis rate and were therefore expected to correlate strongly (Garten 1976, Garten 1978, Duarte 1992, Cornelissen et al. 1997, Thompson et al. 1997). The last derived factor (Factor 4) grouped potassium (K) and aluminium (Al) together as positively associated in the hosts. Within the climbers these elements were found to be negatively correlated, but the factor loading also was lower for K in this case. Within the climbers the percentage of explained variance by Factor 1 was slightly higher than within the self supporting vegetation. Correlation rates between external and internal parameters can help to asses the degree of competition power a plant has in the understorey. Factor loadings of the single parameters were in most cases slightly higher within the climbers. Accordingly the stronger correlations emphasise again how accurate the growth form climber can respond to changes in its environment. The allocation patterns of the derived factor loadings among the plant genera and their abundance on specific plots confirmed these findings. Distribution of the plants along the altitudinal gradient followed their loadings on Factor 1, representing altitude and PFDrel as described above. Plants with high or low leaf contents of a factor specific element furthermore had the highest absolute loadings for this respective factor.

4.4. COMPARISON OF YOUNG AND MATURE LEAVES

Leaf mass per unit area (LMA) is well known to increase with leaf age. This was proofed not only for deciduous trees in temperate zones (e.g. by Reich et al. 1991b), but also for tropical deciduous pioneer trees (Kitajima et al. 2002) and different Amazonian tree species (Reich & Walters 1994). For the tropical vine Syngonium podophyllum (Ackerly 1992) as well as for grapevines (Poni et al 1994) also an increase of LMA along leaf ontogeny was reported. The results of the current ECSF study confirmed these findings for the trees as well as for their adjacent climbers. LMA was low in young leaves, whereas in mature leaves LMA was one third higher. Discussion 99

Leaf nitrogen content (Nmass) is reported to decline generally with increasing leaf age in plants, which enables a translocation of N from old to new leaves and reproductive structures (Field & Mooney 1986). Buchanan-Wollaston (1997) hypothesised that this N decline might by a genetically programmed process, especially during later leaf senescence. In most cases young leaves are more exposed to sun than old leaves. For enhanced shoot carbon gain the nitrogen should be allocated towards the (young) sun leaves (Field 1983). Highest contents of Nmass in youngest tree leaves were found in several studies. Reich & Walters (1994) reported a decline of Nmass in tropical trees during leaf aging, as well as Ackerly & Bazzaz (1995) and Kitajima et al (2002). Same patterns were found for maple and oak by Reich et al (1991) and for cotton plants by

Bondada & Osterhuis (1998). The trees collected on ECSF also had highest Nmass values in the young leaves, with declining N in mature leaves. The climbing vegetation on the other hand kept Nmass quite constant with leaf development and increasing LMA. This was contradictory to the results for grapevines by Poni et al. (1994), where Nmass decreased with leave age as expected. Hikosaka (1996) found growth reactions in the leaf composition of the tropical vine Ipomea tricolor that were more specific according the light conditions. Nmass showed a steep gradient from young to old leaves under normal conditions, when new leaves started to shade older leaf generations. Leaf nitrogen was almost constant, irrespective of leaf age, under steady light conditions. Avoidance of self-shading by horizontal growth is known for the liana Ipomea tricolor (Hikosaka 1996) and recent results from our studies in Madagascar indicate the same strategies for the lianas (Kazda et al. 2003). They showed leaf area densities (LAD) of nearly 1 in the canopy, which means also LAI of 1 and therefore extremely low self-shading. By how far the understorey climbers from ECSF were also able to enhance their leaf alignment remains unknown, but the growth of climbers is generally not orientated that vertically as tree growth, thus reducing self-shading effects. Songwe et al. (1997) reported constant leaf nitrogen with increasing age for Pycnanthus angolensis from Cameroon, but a decrease of Nmass in Terminalia superba. In Gabon (Kazda & Salzer, unpublished) leaves of climbers and trees also did not differ in Nmass between young and mature leaves, although LMA was remarkably lower in young leaves. Three tree species from Cameroon were found to have lower Nmass in young leaves than in fully developed ones, four other trees showed the expected increase of Nmass with age (Kazda & Lösch 1992). Strong herbivory pressure could be a reason for such delayed nitrogen input for the climbers on ECSF. Discussion 100

Low nitrogen content makes leaves less attractive for herbivory. Especially in the early stages of leaf development, low LMA and higher nitrogen concentrations normally cause high herbivory pressure (Coley & Kursar 1996). Therefore low N in young leaves might be an important factor for climbers to survive. Leaf toughness is known to be the main deterrent against herbivory (Reich et al. 1991a, Choong et al. 1992, Dudt & Shure 1994, Choong 1996). Harvesting tough mature leaves leads to high energetic costs for the herbivores, especially as sclerophylls are reported to be low in digestibility (Mattson & Scriber 1987, Waterman et al. 1988), and nutritional quality decreases with leaf maturing (Choong 1996). The time span a herbivore has to spend feeding on a leaf is not only a factor of expensiveness, but also of risk to become predated (Slansky 1993). As low toughness of a leaf can also be expressed by LMA, climbers have to find a way to reduce their attractiveness to herbivores. Although being more expensive than mechanical defences (Gershenzon 1994, Sagers & Coley 1995, Choong 1996), secondary chemicals like tannins and terpens are known to be used as barriers. High concentrations of different secondary defensive compounds were reported for many vines by Hegarty et al. (1991), but some specialised feeding insects may have developed metabolism ways to handle these chemicals during evolution. Accordingly another cheaper way for plants to reduce herbivory pressure might be the reduction of nutrient concentration in young leaves. A delay in nitrogen allocation becomes advantageous until toughness increases, if nearby tree leaves offer high nutritional values for the herbivores. Positive correlation between N content of young leaves and their leaf expansion was described by Kursar & Coley (1991). Rapid growth rates by increasing N input could counterbalance area losses by herbivores on maturing leaves of climbers, still being lower in LMA of climber than of trees.

Area based nitrogen content (Narea) in the ECSF samples was same in young and mature tree leaves, but significantly lower in young climber leaves, confirming the findings from Gabon (Kazda & Salzer, unpublished). This reflects again a reduced nitrogen allocation towards young leaves in the climbing vegetation, whereas the self supporting vegetation already showed full N content, which will be diluted during leaf expansion. On the other hand nitrogen is most useful for expanded leaves with fully developed photosynthetic components. Reich et al. (1991b) found also an increase of Narea with leaf age in maple and oak trees, although Nmass was highest in young leaves. In two tropical pioneer trees

Kitajima et al. (2002) described Narea decrease with leaf age for Urea caracasana, growing under increasing shade. Cecropia longipes on the other hand, growing in full Discussion 101 sunlight, remained constant in its N content. For grapevines a cubic regression was found by Poni et al. (1994) to fit the age/Narea data. In the beginning of leaf development Narea was low, then increasing fast before slowly decreasing again with further aging. All these findings indicate the importance to optimise the balance between investment and carbon gain during leaf expansion and the risk of herbivory. A climbers rapid growth within a patchy light environment requires different leaf nitrogen allocation patterns during time than found in trees. As nitrogen use efficiency is reported to decrease with leaf age (Ishida et al. 1999), an optimisation towards light harvesting and against self shading as well as herbivory pressure becomes necessary, especially for climbers with their reduced LMA. Discussion 102

4.5. CONCLUSIONS

The results of this study confirmed that the reduction of supporting tissues of climbing plants continues on leaf level. Adaptation to the surrounding conditions is more accurate as in self supporting plants. Fast leaf development, low PAR transmission rates and high leaf nutrient contents enable the climbers to be very competitive. Delayed nitrogen flush into young leaves prevents of herbivory. As climbing plants require higher amounts of nutrients than trees, the high abundance of climbers on forest edges and gaps can be explained by the increased nutrient mobilisation rates on such sites. Insufficient nutrient supply on the undisturbed areas of the Podocarpus National Park, high load of epiphytes and mosses on the supporters branches, and high aluminium concentrations in the soils can be a reason for the low abundance of big lianas in the ECSF forest. Still we lack some important data to understand how the network of plant distribution and diversity works. The following shall display the main open questions and some starting-points to answer them:

· According to Hegarty et al. (1991) secondary compounds with defensive functions

should be expected in the climber leaves. Low LMA combined with high Nmass content would otherwise make their leaves very attractive to herbivores (Cherret 1968, Kitajima 1994, Choong et al. 1992, Choong 1996, Wright & Cannon 2001) which finally would lead to enormous maintenance costs and thereby bad economic balances for the climbers. Chemical analyses for these secondary compounds might be necessary for a better understanding of competition strategies between different growth forms under field conditions.

· The photosynthetic rates of climbers and their hosts should also be compared in the tropics, especially with view on investment based rates of carbon gain.

· Can the inversed differences between young and mature leaves in nitrogen allocation also be confirmed with data from other ecosystems, or is low nutrient availability on ECSF the main cause for this phenomenon?

· Further work should also be concentrated on comparing the leaf lifespan of the two growth forms. This would allow precise calculations of the economical balances of these plants.

· Calorimetric measurements of the leaves total energy content could supply substantial data to further investment calculations. Discussion 103

· Knowledge about energy content will get especially important when space acquisition efficiency comparisons between the climbers and their supporters are carried out. First steps in this direction were already done in Madagascar and in Costa Rica, but more accurate methods to calculate the volume that both plants share in the crown have to be developed.

Literature 104

6. LITERATURE

Abrams, M.D. and Mostoller, S.A. (1995): Gas exchange, leaf structure and nitrogen in contrasting successional tree species growing in open and understorey sites during a drought. – Tree Physiology 15: 361-370

Ackerly, DD. (1992): Light, leaf age, and leaf nitrogen concentration in a tropical vine. – Oecologia 89: 596-600

Ackerly, DD. and Bazzaz, F:A. (1995): Leaf dynamics, self-shading and carbon gain in seedlings of a tropical pioneer tree. – Oecologia 101: 289-298

Alonso, C. and Herrera, C.M. (2001): Patterns made of patterns: variation and covariation of leaf nutrient concentrations within and between populations of Prunus mahaleb. – New Phytologist 150: 629-640

Appanah, S. and Putz, F.E. (1984): Climber abundance in virgin dipterocarp forest and the effect of pre-felling climber cutting on logging damage. – The Malaysian Forester 47 (4): 335-342

Avalos, G. and Mulkey, S.S. (1999): Photosynthetic acclimation of the liana Stigmaphyllon lindenianum to light changes in a tropical dry forest canopy. – Oecologia 120: 475- 484

Avalos, G., Mulkey, S.S. and Kitajima (1999): Leaf optical properties of trees and lianas in the outer canopy of a tropical dry forest canopy. – Biotropica 31: 517-520

Balslev, H. (1988): Distribution patterns of Ecuadorian plant species. – Taxon 37: 567-677

Balfour, D.A. and Bond, W.J. (1993): Factors limiting climber distribution and abundance in a southern African forest. – Journal of Ecology 81 (1): 93-100

Barker, M.G. and Pérez-Salicrup, D.R. (2000): Effect of liana cutting on water potential and growth of adult Senna multijuga (Caesalpinioideae) trees in a Bolivian tropical forest. – Oecologia 124 (4): 469-475

Bazzaz, F.A. (1979): The physiological ecology of plant succession. – Annual Review of Ecology and Systematics 10: 351-371

Bazzaz, F.A. and Carlson, R.W. (1982): Photosynthetic acclimation to variability in the light environment of early and late successional plants. – Oecologia 54: 313-316

Bendix, J. and Lauer, W. (1992): Die Niederschlagsjahreszeiten in Ecuador und ihre klimadynamische Interpretation. – Erdkunde 46: 118-134

Bigelow, S.W. (1993): Leaf nutrients in relation to stature and life form in tropical rain forest. – Journal of Vegetation Science 4: 401-408 Literature 105

Björkman, O. (1981): Responses to different quantum flux densities. – In: Lange, O.L., Nobel, P.S., Osmond, C.B. and Ziegler, H. (eds.): Physiological Plant Ecology I. Responses to the Physical Environment. Encyclopaedia of Plant Physiology, New Series, Springer-Verlag, Berlin

Bollmer-Elmer, K.C. (1977): Stickstoff-Düngeeinflüsse von Intensiv-Grünland auf Streu- und Moorwiesen. – Veröff. ETH Zürich, Heft 63

Bondada, B.R. and Osterhuis, D.M. (1998): Relationships between nitrogen content and net gas exchange components of a cotton leaf during ontogeny. – Photosynthetica 35: 631-635

Borchsenius, F. (1997): Patterns of plant species endemism in Ecuador. – Biodiversity and Conservation 6: 379-399

Bruijnzeel, L.A., Waterloo, M.J., Proctor, J. Kuiters, A.T. and Kotterink, B. (1993): Hydrological observations in montane rainforests on Gunung Silam, Sabah, Malaysia, with special reference to the Massenerhebung effect. – Journal of Ecology 81: 145-167

Buchanan-Wollaston, V. (1997): The molecular biology of leaf senescence. – Journal of experimental Biology 48: 181-199

Budikova, S.. (1999): Structural changes and aluminium distribution in maize root tissues. – Biologia Plantarum 42: 259-266

Bussman, R.W. (2001): The montane forests of Reserva Biológica San Francisco (Zamora- Chinchipe, Equador) – vegetation zonation and natural regeneration. – Die Erde 132: 11-24

Caballé, G (1993): Liana structure, function and selection: a comparative study of xylem cylinders of tropical rainforest species in Africa and America. – Botanical Journal of the Linnean Society 113: 41-60

Caballé, G and Martin, A. (2001): Thirteen years of change in trees and lianas in a Gabonese rainforest. – Plant Ecology 152 (2): 167-173

Campbell, E.J.F. and Newberry, D.M. (1993): Ecological relationships between lianas and trees in lowland rain forest in Sabah, East Malaysia. – Journal of Tropical Ecology 9 (4): 469-490

Carse, L.E., Fredericksen, T.S., and Licona, J.C. (2000): Liana-tree species associations in a Bolivian dry forest. – Tropical Ecology 41 (1): 1-10

Carter, G.A. and Teramura, A.H. (1988): Vine photosynthesis and relationships to climbing mechanisms in a forest understorey. – American Journal of Botany 75: 1011-1118 Literature 106

Castellanos, A., Mooney, H.A., Bullock, S.H., Jones, C. and Robichaux, R. (1989): Leaf stem and metamer characteristics of vines in a tropical deciduous forest in Jalisco, Mexico. – Biotropica 21: 41-49

Castellanos, A. (1991): Photosynthesis and gas exchange of vines. – In: Putz, F.E. and Mooney, H.A. (eds.): The biology of vines. Cambridge Univ. Press, Cambridge, UK

Chalmers, A.C. and Turner, J.C. (1994): Climbing plants in relation to their supports in a stand of dry rainforest in the Hunter Valley, New South Wales. – Proceedings of the Linnean Society of New South Wales 114 (1-4): 73-90

Chapin, F.S. (1980): The mineral nutrition of wild plants. – Annual Review of Ecology and Systematics 11: 233-260

Chazdon, R. L. and Fetcher, N. (1984): Photosynthetic light environments in a lowland tropical rain-forest in Costa Rica. – Journal of Ecology 72: 553-564

Chen, H.Y.H. and Klinka, K. (1997): Light availability and photosynthesis of Pseudotsuga menziesii seedlings grown in the open and in the forest understorey. – Tree Physiology 17: 23-29

Cherret, J.M. (1968): A simple penetrometer for measuring leaf toughness in insect feeding studies. – Economic Entomology 61: 1736-1738

Chittibabu, C. V. and Parthasarathy, N. (2001): Liana diversity and host relationships in a tropical evergreen forest in the Indian Eastern Ghats. – Ecological Research 16 (3): 519-529

Choong, M.F. (1996): What makes a leaf tough and how this affects the pattern of Castanopsis fissa leaf consumption by caterpillars. – Functional Ecology 10: 668-674

Choong, M.F., Lucas, P.W., Ong, J.S.Y., Pereira, B., Tan, H.T.W. and Turner, I.M. (1992): Leaf fracture toughness and sclerophylly: their correlations and ecological implications. – New Phytologist 121: 597-610

Coley, P.D. and Kursar, T.A. (1996): Anti-herbivore defenses of young tropical leaves: physiological constraints and tradeoffs. – In: Smith, A.P., Mulkey, S.S. and Chazdon, R.L. (eds.): Tropical Forest Plant Ecophysiology. Chapman & Hall, New York, USA

Coley, P., Bryant, J. and Chapin, F. (1985): Resource availability and plant antiherbivory defense. – Science 230, 895-899

Cornelissen, J.H.C., Castro-Diez, P. and Hunt, R. (1996): Seedling growth, allocation and leaf attributes in a wide range of woody plant species and types. – Journal of Ecology 84, 755-765 Literature 107

Cornelissen, J.H.C., Werger, M.J.A., Castro-Diez, P., van Rheenen, J.W.A. and Rowland, A.P. (1997): Foliar nutrients in relation to growth, allocation and leaf traits in seedlings of a wide range of woody plant species and types. – Oecologia 111, 460-469

Croat, T.B. (1987): Flora of Barro Colorado Island – Stanford Univ. Press, Stanford, Ca, USA

Cuenca, G., Herrera, R. and Medina, E. (1990): Aluminium tolerance in trees of a tropical cloud forest. – Plant and Soil 125: 169-175

Darkó, É., Bakos, F., Szakács, É., Dulai, S. and Barnabás, B. (2002): Long-term phytotoxic effects of aluminium on Al-susceptible and Al-tolerant genotypes of wheat selected from microspores. – Acta Biologica Szegediensis 46: 87-88

Darwin, C. (1897): On the movements and habits of climbing plants. – Journal of the Linnean Society (Botany) 9: 1-118

Dewalt, S.J.,. Schnitzer, S.A. and Denslow, J.S. (2000): Density and diversity of lianas along a chronosequence in a central Panamanian lowland forest. – Journal of Tropical Ecology 16 (1): 1-19

Dillenburg, L.R., Whigham, D.F., Teramura, A.H. and Forseth, I.N. (1993): Effects of vine competition on availability of light, water and nitrogen to a tree host (Liquidambar styraciflua). – American Journal of Botany 80: 244-252

Dillenburg, L.R., Teramura, A.H., Forseth, I.N and Whigham, D.F. (1995): Photosynthesis and biomass allocation responses of Liquidambar styraciflua (Hamamelidaceae) to vine competition. – American Journal of Botany 82: 454-461

Donald, D.G.M., Lange, P.W., Schultz, C.J. and Morris, A.R. (1987): The application of fertilisers to pines in southern Africa. – South African Forestry Journal 141: 53-62

Duarte, C.M. (1992): Nutrient concentration of aquatic plants: patterns across species. – Limnology and Oceanography 37: 882-889

Dudt, F.J. and Shure, D.J. (1994): The influence of light and nutrients on foliar phenolics and insect herbivory. – Ecology 75: 86-98

Dziedzioch, C. (2001): Artzusammensetzung und Ressourcenangebot kolibribesuchter Pflanzen im Bergregenwald Südecuadors. – Dissertation Thesis at the Faculty for Nature-Sciences, University of Ulm

Edwards, P.J. (1982): Studies of mineral cycling in a montane rain forest in New Guinea. V. Rates of cycling in throughfall and litter fall. – Journal of Ecology 70: 807-827

Eilu, G. (2000): Liana abundance in three tropical rain forests of western Uganda. – Selbyana 21 (1-2): 30-37

Eliasson, U. (1991): Preliminary checklist of genera of vascular plants occurring in Ecuador. – Botanical Museum, University of Gothenburg Literature 108

Ellsworth, D.S. and Reich, P.B. (1992): Leaf mass per area, nitrogen content and photosynthetic carbon gain in Acer sacchurum seedlings in contrasting forest light environments. – Functional Ecology 6: 423-435

Ellsworth, D.S. and Reich, P.B. (1993): Canopy structure and vertical patterns of photosynthesis and related leaf traits in a deciduous forest. – Oecologia 96: 169-178

Erwin, T.L. (1982): Tropical forests: their richness in Coleoptera and other arthropod species. – The Coleoptera Bulletin 36: 74-75

Evans, J.R. (1989): Photosynthesis and nitrogen relationships in leaves of C3 plants. – Oecologia 78: 9-19

Evans, J.R. (1998): Photosynthetics characteristics of fast- and slow-growing species. – In: Lambers, H., Poorter, H. and Van Vuuren, M.M.I. (eds.): Inherent Variation in Plant Growth. Physiological mechanisms and Ecological Consequences. Backhuis Publishers, Leiden, The Netherlands

Evans, J.R. (1999): Leaf anatomy enables more equal access to light and CO2 between chloroplasts. – New Phytologist 143: 93-104

Evans, J.R. and Poorter, H. (2001): Photosynthetic acclimation of plants to growth irradiance: the relative importance of specific leaf area and nitrogen partitioning in maximizing carbon gain. – Plant, Cell and Environment 24: 755-767

Ewers, F.W. , Fisher, J.B. and Chiu, S.-T. (1989): Water transport in the liana Bauhinia fassoglensis (Fabaceae). – Plant Physiology 91: 1625-1631

Ewers, F.W. (1985): Xylem structure and water conduction in conifer trees, dicot trees, and lianas. – International Association of Wood Anatomists Bulletin 6: 309-317

Ewers, F.W., Fisher, J.B. and Fichtner, K. (1991): Water flux and xylem structure in vines. – In: Putz, F.E. and Mooney, H.A. (eds.): The biology of vines. Cambridge Univ. Press, Cambridge, UK

Field, C. (1983): Allocating leaf nitrogen for the maximisation of carbon gain: leaf age as control on the allocation program. – Oecologia 56: 341-347

Field, C and Mooney, H.A. (1986): The photosynthesis-nitrogen relationship in wild plants. – In: Givnish, T.V. (ed.): In the economy of form and function. Cambridge Univ. Press, Cambridge, UK

Finck, A. (1969): Pflanzenernährung in Stichworten. – Hirt, Kiel

Finckh, M. and Paulsch, A. (1995): Araucaria araucaria – Die ökologische Strategie einer Reliktkonifere. – Flora 190: 365-382 Literature 109

Fonseca, C.R., Overton, J.M., Collins, B. and Westoby, M. (2000): Shifts in trait combinations along rainfall and phosphorus gradients. – Journal of Ecology 88: 964- 977

Fox, J.E.D. (1968): Logging damage and the influence of climber cutting prior to logging in the lowland dipterocarp forest of Sabah. – Malayan Forester 31 (4): 326-347

Freiberg, M. and Turton, S.M. (2003): Der Einfluss des Klimas auf die Populationsstruktur des epiphytischen Vogelnestfarnes, Asplenium nidus in Nordost-Queensland, Australien. – Presentation on the 16th Conference of the German Society of Tropical Ecology in Rostock 2003

Garten, C.T. (1976): Correlations between concentrations of elements in plants. – Nature 361: 686-688

Garten, C.T. (1978): Multivariate perspectives on the ecology of plant mineral element composition. – American Naturalist 112: 533-544

Gentry A.H. (1983): Lianas and the "paradox" of contrasting latitudinal gradients in wood and litter production – Tropical Ecology 24: 63-67

Gentry, A.H. (1985): An ecotaxonomic survey of Panamanian lianas. – In: D'Arcy, W. and Correa, M. (eds.): Historia Natural de Panamá. Monographs of Systematic Botany, Missouri Botanical Garden, Saint Lois

Gentry, A.H. (1991): The distribution and evolution of climbing plants. – In: Putz, F.E. and Mooney, H.A. (eds.): The biology of vines. Cambridge Univ. Press, Cambridge, UK

Gentry, A.H. and Dodson, C. (1987): Contribution of nontrees to species richness of a tropical rain forest. – Biotropica 19 (2): 149-156

Gershenzon, J. (1994): Metabolic costs of terpenoid accumulation in higher plants. – Journal of Chemical Ecology 20: 1281-1328

Gerwing, J.J. (2001): Testing liana cutting and controlled burning as silvicultural treatments for a logged forest in the eastern Amazon. – Journal of Applied Ecology 38 (6): 1264- 1276

Givnish, T.J. and Vermeij, G.J. (1976): Sizes and shapes of liane leaves. – The American naturalist 110: 743-778

Greer, D.H. (1996): Photosynthetic development in relation to leaf expansion in Kiwifruit (Actinidia deliciosa) vines during growth in a controlled environment. – Australian Journal of Plant Physiology 23: 541-549

Grubb, P.J. (1977): Control of forest growth and distribution on wet tropical mountains: with special reference to mineral nutrition. – Annual Reviews of Ecology and Systematics 8: 83-107 Literature 110

Grubb, P.J., Lloyd, J.R., Pennington, T.D. and Whitmore,T.C. (1963): A comparison of montane and lowland rainforest in Ecuador. I. The forest structure, physiognomy, and floristics. – Journal of Ecology 51: 567-601

Gulmon, S.L. and Mooney, H.A. (1986): Costs of defense and their effects on plant productivity. – In: Givnish, T.V. (ed.): In the economy of form and function. Cambridge Univ. Press, Cambridge, UK

Hättenschwiler, S. (2002): Liana seedling growth in response to fertilisation in a neotropical forest understorey. – Journal of Applied Ecology 3: 135-143

Hagedorn, A. (2001): Extent and significance of soil erosion in southern Ecuador. – DIE ERDE 132: 75-92.

Hampp, R. and Schnabl, H. (1975): Effect of aluminium ions on 14 CO2-fixation and membrane system of isolated spinach chloroplasts – Zeitschrift für Pflanzenphysiologie 76: 300-306

Hanson, H.C. (1917): Leaf-structure as related to environment. – American Journal of Botany 4: 533-560

Hara, K. (1987): A categorization of plant communities as habitats for climbing plants. – Ecological Reviews 21 (2): 55-66

Haridasan, M. (1982): Aluminium accumulation of some cerrado native species of central Brazil. – Plant and Soil 65: 265-273

Harling, G. (1986): Current Scandinavian botanical research in Ecuador. – Reports of the Botanical Institute, University Aarhus 15: 9-10

Harris, W.R., Berthon, G., Day, J.P., Exley, C. Flaten, T.P., Forbes, W.F. et al. (1996): Speciation of aluminium in biological systems. – Journal of Toxicology and Environmental Health 48: 543-568

Hegarty, E.E. (1991): Vine-host interactions. – In: Putz, F.E. and Mooney, H.A. (eds.): The biology of vines. Cambridge Univ. Press, Cambridge, UK

Hegarty, E.E. and Caballé, G. (1991): Distribution and abundance of vines in forest communities. – In: Putz, F.E. and Mooney, H.A. (eds.): Life Forms and Dynamics in Tropical Forests. Cambridge Univ. Press, Cambridge, UK

Hegarty, M.P., Hegarty, E.E. and Gentry, A.M. (1991): Secondary compounds in vines with an emphasis on those with defensive functions. – In: Putz, F.E. and Mooney, H.A. (eds.): Life Forms and Dynamics in Tropical Forests. Cambridge Univ. Press, Cambridge, UK

Heinen, K. (2003): Investitionsmuster in Blättern von Lianen und ihren Trägerbäumen sowie deren gemeinsame Raumnutzung auf unterschiedliche gestörten Flächen. – Diploma Thesis at the Faculty for Nature-Sciences, University of Ulm, Germany Literature 111

Henderson, A., Churchill, S.P. and Luteyn, W.H. (1991): Neotropical plant diversity. – Nature 351: 21-22

Hikosaka, K. (1996): Effects of leaf age, nitrogen nutrition and photon flux density on the organization of the photosynthetic apparatus in leaves of a vine (Ipomoea tricolor Cav.) grown horizontally to avoid mutual shading of leaves. – Planta 198: 144-150

Hikosaka, K. and Terashima, I. (1995): A model of the acclimation of photosynthesis in the

leaves of C3 plants to sun and shade with respect to nitrogen use. – Plant, Cell and Environment 18: 605-618

Hirose, T. and Werger, M.J.A. (1994): Photosynthetic capacity and nitrogen partitioning among species in the canopy of a herbaceous plant community. – Oecologia 100: 203-212

Hobbie, S.E. and Gough, L. (2002): Foliar and soil nutrients in tundra on glacial landscapes of contrasting ages in northern Alaska. – Oecologia 131: 453-462

Horst, W.J., Schmohl, N. Kollmeier, M., Baluska, F. and Sivaguru, M. (1999): Does aluminium affect root growth of maize through interaction with the cell wall – plasma membrane – cytoskeleton continuum? – Plant and Soil 215: 163-174

Ishida, A., Uemura, A., Koike, N., Matsumoto, Y. and Hoe, A.L. (1999): Interactive effects of leaf age and self-shading on leaf structure, photosynthetic capacity and chlorophyll fluorescence in the rain forest tree, Dryobalanops aromatica. – Tree physiology 19: 741-747

Jackson, L.R.W. (1967): Effect of shade on leaf structure of deciduous tree species. – Ecology 48: 498-499

Jacobs, M. (1976): The study of lianas. – Flora Malesiana Bulletin 29: 2610-2618

Kazda, M. and Lösch, R. (1992): Element dynamics in canopy leaves of a tropical rain forest in Cameroon. – In Hallé, F. and Pascal, O. (eds.): Biologie d’une Canopée de Foret Équatoriale. – Raport de Mission: Radeau des Cimes, Octobre/Novembre 1991, Réserve de Campo, Cameroun

Kazda, M. and Mehltreter, K. (2001): Contrasting leaf nutrition and leaf mass per unit area in lianas and trees from the subtropical island Martin Garcia, Argentina. – In Gottsberger, G. and Liede, S. (eds.): Life Forms and Dynamics in Tropical Forests. Gebrüder Bornträger Verlagsbuchhandlung, D

Kazda, M. and Salzer, J. (2000): Leaves of lianas and self-supporting plants differ in mass per unit area and in nitrogen content. – Plant Biology 2 (3): 268-271

Kazda, M., Johnson, C.M., Ranantenainasoa, H. and Salzer, J. (2003): Cost of space acquisition by lianas and trees in a tropical rain forest on Madagascar – Report from Oeration Canopeé, Masoala 2001, in press Literature 112

Kesel, A.B., Junge, M.M. and Nachtigall, W. (1999): Einführung in die angewandte Statistik für Biowissenschaftler. – Birkhäuser Verlag, Basel: 136-139

Kitajima, K. (1994): Relative importance of photosynthetic traits and allocation patterns as correlates of seedling shade tolerance of 13 tropical trees. – Oecologia 98: 419-428

Kitajima, K., Mulkey, S.S., Samaniego, M. and Wright, S.J. (2002): Decline of photosynthetic capacity with leaf age and position in two tropical pioneer tree species. – American Journal of Botany 89: 1925-1932

Körner, Ch., Bannister, P and Mark, A.F. (1986): Altitudinal variation in stomatal conductance, nitrogen content and leaf anatomy in different plant life forms in New Zealand – Oecologia 69: 577-588

Kotz, L., Kaiser, G. ,Tschöpel, P. and Tölg, G. (1972): Aufschluß biologischer Matrices für die Bestimmung sehr niedriger Spurenelementgehalte bei begrenzter Einwaage mit Salpetersäure unter Druck in einem Teflongefäß. – Zeitschrift für Analytische Chemie 260: 207-209

Kull, O. and Niinemets, Ü. (1993): Variation in leaf morphometry and nitrogen concentration in Betula pendula Roth., Coryllus avellana L. and Lonicera xylosteum L. – Tree Physiology 12: 311-318

Kursar, T.A. and Coley, P.D. (1991): Nitrogen content and expansion rate of young leaves of rain forest species: implications for herbivory. – Biotropica 23: 141-150

Larcher, W. (1994): Ökophysiologie der Pflanzen. – 5. Auflage, UTB, Verlag Eugen Ulmer, Stuttgart, D

Laurance, W.F., Perez-Salicrup, D., Delamonica, P., Fearnside, P.M.., D'Angelo, S., Jerozolinski, A., Pohl, L. and Lovejoy, T. (2001): Rain forest fragmentation and the structure of Amazonian liana communities. – Ecology 82 (1): 105-116

Linsenmair, K.E. (1990): Tropische Biodiversität: Befunde und offene Probleme. – Verh Deutsch Zool Ges 83: 245-261

Litherland, M., Aspden, J.A. and Jemielta, R.A. (1994): The metamorphic belts of Ecuador. – Overseas Memoir of the British Geological Society, No 11

Lösch, R. (2001): Wasserhaushalt der Pflanzen. – 1. Auflage, UTB, Quelle und Meyer, Wiebelsheim

Logan, G.A., Fredericks, D.J., Smith, C. and Heggie, DT. (2001): Sources of organic matter in Wallis lake. – AGSO Research Newsletter MAY 2001: 15-20

Loren-Plucinska, G. and Ziegler, H. (1996): Changes in ATP levels in Scot pine needles during aluminium stress. – Photosynthetica 32: 141-144 Literature 113

Lowe, R.G. (1978): Experience with the tropical shelterwood system of regeneration in natural fores in nigeria. – Forest Ecology and Management 1: 193-212

Lowe, R.G. and Walker, P. (1977): Classification of canopy, stem, crown status and climber infestation in natural tropical forest in Nigeria. – Journal of Applied Ecology 14: 897-903

Lüttge, U. (1997): Physiological Ecology of Tropical Plants. – Springer-Verlag Berlin, Heidelberg, New York

Lutz, H.J. (1943): Injuries to trees caused by Celastrus and Vitis. – Bulletin of the Torrey Botanical Club 70 (4): 436-439

Ma, J.F., Hiradate, S., Nomoto, K. Iwashita, T. and Matsumoto, H. (1997): Internal Detoxification Mechanism of Al in Hydrangea (Identification of Al Form in the Leaves). – Plant Physiology 113: 1033-1039

Machado, J-L. and Reich, P. B. (1999): Evaluation of several measures of canopy openness as predictors of photosynthetic photon flux density in deeply shaded conifer- dominated forest understory. – Canadian Journal of Forest Research 29: 1438-1444

Madsen, J.E. (1989): Aspectos generales de flora y vegetación del Parque Nacional Podocarpus. – Parque Nacional Podocarpus, Boletín informativo sobre biología, conservación y vida silvestre. Universidad Nacional, Facultad de Ciencias Veterinarias, Loja, Ecuador

Makino, A. and Osmond, B. (1991): Effects of nitrogen nutrition on nitrogen partitioning between chloroplasts and mitochondria in pea and wheat. – Plant Physiology 96: 355- 362

Maldonado, A.N. (1985): Contribución al estudio del clima en la provincia de Loja. – Revista Estudios Universitarios, Universidad Nacional de Loja, 1: 11-140

Marschner, H. (1995): Mineral nutrition of higher plants – 2nd Edition, Academic Press, London, UK

Matsumoto, H. (2000): Cell biology of aluminium toxicity and tolerance in higher plants. – International Review of Cytology 200: 1-46

Mattson, W.J. and Scriber, J.M. (1987): Nutritional ecology of insect folivores of woody plants: nitrogen, water, fiber, and mineral considerations – In: Slansky, F. and Rodriguez, J.G. (eds.): Nutritional Ecology of Insect, Mites, Spiders, and Related Invertebrates. John Wiley & Sons, New York, USA

May, R.M. (1996): Introduction. – In: Hochberg, M.E., Clobert, J. and Barrault, R. (eds.): Aspects of the genesis and maintenance of biological diversity. Oxford Univ. Press, Oxford, UK Literature 114

McGarigal, K., Cushman, S. and Stafford, S. (2000): Multivariate statistics for wildlife and ecology research. – Springer-Verlag, New York

Miyazawa, S., Satomi, S. and Terashima, I. (1998): Slow leaf development of evergreen broad-leaved tree species in Japanese war temperate forests. – Annals of Botany 82 (6): 859-869

Mo, J., Zhang, D., Huang, Z. Yu, Q. and Kong, G. (2000): Distribution pattern of nutrient elements in plants of Dinghushan lower subtropical evergreen broad-leaved forest. – Journal of Tropical and Subtropical Botany 8 (3): 198-206

Montgomery, G. and Sunquist, M. (1987): Habitat selection and use by two-toed and three-toad sloths. – In: Montgomery, G. (ed.): The ecology of Arboreal Folivores. Smithsonian Institution Press, Washington DC, USA

Mooney, H.A., Ferrar, P.S. and Slayter R.O. (1978): Photosynthetic capacity and carbon allocation patterns in diverse growth forms of Eucalyptus. – Oecologia 31: 103-111

Moustakas, M., Ouzounidou, G. and Lannoye, R. (1993): Rapid screening for aluminium tolerance in cereals by use of the chlorophyll fluorescence test. – Plant Breeding 111: 343-346

Moustakas, M. and Ouzounidou, G. (1994): Increased non-photochemical quenching in leaves of aluminium-stressed wheat plants is due to Al3+-induced elemental loss. – Plant Physiology and Biochemistry 32: 527-532

Moustakas, M., Eleftheriou, E.P. and Ouzounidou, G. (1997): Short-term effects of aluminium stress at alkaline pH on the structure and function of the photosynthetic apparatus. – Photosynthetica 34: 169-177

Mueller-Dombois, D. and Ellenberg H. (1974): Aims and methods of vegetation ecology – John Wiley & Sons, New York, USA

Mulkey, S.S., Kitajima, K. and Wright, S.J. (1995): Photosynthetic capacity and leaf longevity in the canopy of a dry tropical forest. – Selbyana 16: 169-173

Muthuramkumar, S. and Parthasarathy, N. (2001): Tree-liana relationships in a tropical evergreen forest at Varagalaiar, Anamalais, Western Ghats, India. – Journal of Tropical Ecology 17 (3): 395-409

Nabe-Nielsen, J. (2001): Diversity and distribution of lianas in a neotropical rain forest, Yasuni National Park, Ecuador. – Journal of Tropical Ecology 17 (1): 1-19

Naumann, A. and Horst, W.J.. (2000): Aluminium transport in relation to organic acid concentrations in shoot exudates of Hydrangea macrophylla. – Poster presentation on the Conference of the German Society for Plantnutrition in Gießen 2000. Literature 115

Nicholson, D.J. (1965): A review of natural regeneration in the dipterocarp forests of Sabah. – The Malayan Forester 28: 4-26

Niinemets, Ü. (1995): Distribution of foliar carbon and nitrogen across the canopy of Fagus sylvatica: adaptation to a vertical light gradient – Acta Oecologica 16: 525-541

Niinemets, Ü., Kull, O. and Tenhunen J.D. (1998): An analysis of light effects on foliar morphology, physiology, and light interception in temperate deciduous woody species of contrasting shade tolerance. – Tree Physiology 18: 681-696

Ohki, K. (1986): Photosynthesis, chlorophyll, and transpiration responses in aluminium stressed wheat and sorghum. – Crop Science 26: 572-575

Osmond, C.B. (1983): Photosynthesis of wheat leaves in relation to age, iluminance and nutrient supply: II. Results. – Oecologia 57: 316-321

Padaki, A. and Parthasarathy N. (2000): Abundance and distribution of lianas in tropical lowland evergreen forest of Agumbe, central Western Ghats, India. – Tropical Ecology 41 (2): 143-154

Parren, M. and Bongers, F. (2001): Does climber cutting reduce felling damage in southern Cameroon? – Forest Ecology and Management 141 (3): 175-188

Paulsch, A. (2001): Development and application of a classification system for undisturbed and disturbed tropical montane forests based on vegetation structure. – Dissertation Thesis at the Faculty for Biology, Chemistry and Geo-Sciences, University of Bayreuth

Peñalosa, J. (1982): Morphological specialization and attachment success in two twining lianas. – American Journal of Botany 69: 1043-1045

Peñalosa, J. (1983): Shoot dynamics and adaptive morphology of Ipomea phillomega, a tropical rainforest liane. – Annals of Botany 52 (5): 737-754

Pereira, W.E., de Siqueira, D.L., Martinez, C.A. and Puiati, M. (2000): Gas exchange and chlorophyll fluorescence in four citrus rootstocks und aluminium stress. – Journal of Plant Physiology 157: 513-520

Pérez-Salicrup, D.R. (2001): Effect of liana cutting on tree regeneration in a liana forest in Amazonian Bolivia. – Ecology 82 (2): 389-396

Pinard, M.A. and Putz, F.E. (1994): Vine Infestation of large remnant trees in logged forest in Sabah, Malaysia: Biochemical facilitation in vine succession. – Journal of Tropical Forest Science 6 (3): 302-309 Literature 116

Poni, S., Intrieri, C. and de Jong, R. (1994): Interactions of leaf age, fruiting, andexogenous cytokinins in sangiovese grapevines under non-irrigated conditions. II Chlorophyll and nitrogen content. – American Journal of Enology and Viticulture 45: 278-284

Poorter, H. and de Jong, R. (1999): A comparison of specific leaf area, chemical composition and leaf construction costs of field plants from 15 habitats differing in productivity. – New Phytologist 143: 163-176

Proctor, J., Anderson, J.M., Chai, P. and Vallack, H.W. (1983): Ecological studies in four contrasting lowland rainforests in Gunung Mulu National Park, Sarawak. I. Forest environment, structure and floristics. – Journal of Ecology 71: 237-260

Putz, F.E. (1983): Liana biomass and leaf area of a “Terra Firme” forest in the Rio Negro basin, Venzuela. – Biotropica 15 (3): 185-189

Putz, F.E. (1984): The natural history of lianas on Barro Colorado Island, Panama. – Ecology 65 (6): 1713-1724

Putz, F.E. (1985): Woody vines and forest managment in Malaysia. – Commonwealth Forestry Review 64 (4): 359-365

Putz, F.E. (1991): Silvicultural effects of lianas. – In: Putz, F.E. and Mooney, H.A. (eds.): The biology of vines. Cambridge Univ. Press, Cambridge, UK

Putz, F.E. (1995): Vines in treetops: consequences of mechanical dependence. – In: Lowman, M.D. and Nadkarni, N.M. (eds.): Forest Canopies. Academic Press, London, UK

Putz, F.E. and Chai, P. (1987): Ecological Studies of lianas in Lambir National Park, Sarawak, Malaysia. – Journal of Ecology 75: 523-531

Putz, F.E. and Mooney, H.A. (eds.) (1991): The biology of vines. Cambridge Univ. Press, Cambridge, UK

Putz, F.E. and Holbrook, N.M. (1991): Biomechanical studies of vines. – In: Putz, F.E. and Mooney, H.A. (eds.): The biology of vines. Cambridge Univ. Press, Cambridge, UK

Putz, F.E. and Windsor, D.M. (1987): Liana phenology on Barro Colorado Island, Panama. – Biotropica 19: 334-341

Prosperi, J. and Caballé, G. (2001): Lianas and hemiepiphytes: Distribution, development, and adaptations. – Selbyana 22 (2) : 197-212

Reich, P.B., Abrams, M.D., Ellsworth, D.S., Kruger, E.L. and Tabone, T.J. (1990): Fire affects ecophysiology and community dynamics of central Wisconsin oak forest regeneration. – Ecology 71: 2179-2190 Literature 117

Reich, P.B., Ellsworth, D.S., Walters, M.B., Vose, J.M., Gresham, C., Volin, J.C. and Bowman, W.D. (1999): Generality of leaf trait relationships: a test across six biomes. – Ecology 80: 1955-1969

Reich, P.B., Klöppel, B.D., Ellsworth, D.S. and Walters, M.B. (1995): Different photosynthesis- nitrogen relations in deciduous hardwood and evergreen coniferous tree species. . – Oecologia 104: 24-30

Reich, P.B. and Walters, M.B. (1994): Photosynthesis-nitrogen relations in Amazonian tree species. II Variation in nitrogen vis-à-vis specific leaf area influences mass- and area- based expressions. – Oecologia 97: 73-81.

Reich, P.B., Walters, M.B. and Ellsworth, D.S. (1991a): Leaf lifespan as a determinant of leaf structure and function among 23 Amazonian tree species. . – Oecologia 86: 16- 24

Reich, P.B., Walters, M.B. and Ellsworth, D.S. (1991b): Leaf age and season influence the relationships between leaf nitrogen, leaf mass per area and photosynthesis in maple and oak trees. – Plant Cell and Environment 14: 251-259.

Rollet, B. (1969): Le régénération naturelle en foret dense humide sempervirente de plaine de la Guyane Venezulienne. – Bois et Forets des Tropiques 14: 19-38

Rollet, B. (1971): La regeneración naturel en bosque denso siempreverde de llanura de la Guyanae Venezolana. – Instituto Forestal Latino-Americano de Investigacion y Capatacacion, Merida Venez 35: 39-73

Rundell, P.W. and Franklin T. (1991): Vines in arid and semi-arid ecosystems. – In: Putz, F.E. and Mooney, H.A. (eds.): The biology of vines. Cambridge Univ. Press, Cambridge, UK

Sauer, W. (1971): Geologie von Ecuador. – Gebrüder Borntraeger, Berlin

Sage, R.F. and Pearcy, R.W. (1987): The nitrogen use efficiency of C3 and C4 plants. II. Leaf nitrogen effects on the gas exchange characteristics of Chenopodium album L. and Amaranthus retroflexus L.. – Plant Physiology 84: 959-963

Sagers, C.L. and Coley, P.D. (1995): Benefits and costs of defence in a neotropical shrub. – Ecology 76: 1835-1843

Schildknecht, P.H.P.A. and Vidal, B.C. (2002): A role for the cell wall in Al3+ resistance and toxicity: crystallinity and availability of negative charges. – Int Arch Biosci: 1087-1095

Schmithüsen, J. (1968): Allgemeine Vegetationsgeographie. – Lehrbuch der Allgemeinen Geographie Band IV, Walter de Gruyter, Berlin

Schmithüsen, J. (1976): Atlas zur Biogeographie. – Meyers großer physischer Weltatlas Band 3, Bibliographisches Institut, Mannheim Literature 118

Schmitt, D. (2003): Liana sap flow in a tropical montane forest in South-Ecuador. – Poster Presentation on the Yearly Conference of the GfÖ-AK 2003, Stuttgart/Hohenheim, Germany

Schmohl, N. and Horst, W.J. (2001): Cell-wall composition modulates aluminium toxicity. – Plant nutrition - Food security and sustainability of agro-ecosystems: 262-263

Schnitzer S.A., Dalling, J.W. and Carson, W.P. (2000): The impact of lianas on tree regeneration in tropical forest canopy gaps: Evidence for an alternative pathway of gap-phase regeneration. – Journal of Ecology 88 (4): 655-666

Schnitzer, S.A. and Bongers, F. (2002): The ecology of lianas and their role in forests. – Trends in Ecology and Evolution 17 (5): 223-230

Schowalter, T.D. and Ganio, L.M. (1998): Vertical and seasonal variation in canopy arthropod communities in an old-growth conifer forest in southwestern Washington, USA. – Bulletin of Entomological Research 88: 633-640

Schrumpf, M. (1999): Genese, Klassifikation und Nährstoffgehalte tropischer Böden entlang eines Höhentransekts an der Andenostabdachung Südecuadors. – Unpublished Diploma thesis at the Institute of Soil Science and Soil Geography, University of Bayreuth

Schulze, E.-D. and Küppers, M. (1985): Responses of Pinus sylvestris to magnesium deficiency. – In: Turner, H. and Tranquillini, W. (eds.): Establishment and tending of subalpine forest: research and mangement. Proc. 3rd IUFRO Workshop, Eidg. Anst. forstl. Versuchswesen Ber., 270, 193-196

Siccama, T.G., Weir, G. and Wallace, K. (1976): Ice damage in mixed hardwood forest in Connecticut in relation to Vitis infestation. – Bulletin of the Torrey Botanical Clubr 103 (4): 180-183)

Sims, D.A. and Pearcy, R.W. (1994): Scaling sun and shade photosynthetic acclimation of Alocasia macrorrhiza to whole-plant performance: I. Carbon balance and allocation at different daily photon flux densities. – Plant, Cell and Environment 17 (8): 881-887

Slansky, F., Jr. (1993): Nutritional ecology: the fundamental quest for nutrients. – In: Stamp, N.E. and Casey, M. (eds.): Caterpillars Ecological and Evolutionary Constraints on Foraging. Chapman and Hall, New York, USA

Smart, R.E. and Coombe, G.B. (1983): Water relations of grapevines. – In: Kozlowski, T.T. (ed.): Water deficits and plant growth 7, 137-196, Academical Press, New York, USA

Soil Survey Staff (1998): Keys to soil taxonomy. - 8th edition. – Internet version: http://www.statlab.iastate.edu/soils/keytax/KeystoSoilTaxonomy1998.pdf Literature 119

Songwe, N.C., Fasehun, F.E. and Okali, D.U.U. (1997): Leaf nutrient dynamics of two tree species and litter nutrient content in Southern Bakundu Forest Reserve, Cameroon. – Journal of Topical Ecology 13: 1-15

Statistica ’99 edition, Kernel release 5.5A: Help-file in the module “Basic Statistics” for the topic “Dependent t-Test”. StatSoft Inc., Tulsa, USA

Steinhard, U. (1979): Untersuchungen über den Wasser- und Nährstoffhaushalt eines andinen Wolkenwaldes in Venezuela. – Göttinger Bodenkundliche Berichte 56: 1-146

Sterck, F.J. (1999): Crown development in tropical rain forest trees in gaps and understorey. – Plant Ecology 143 (1): 89-98

Stern, M.J.. (1995): Vegetation recovery on earthquake-triggered landslide sites in the Ecuadorian Andes. – In: Churchill, S.P., Balslev, H., Forero, E. and Luteyn, J.L. (eds.): Biodiversity and conservation of neotropical montane forests. The New York Botanical Garden, New York, USA

Stevens, G.C. (1987): Lianas as structural parasites: The Bursera simaruba example. – Ecology 68(1): 77-81

Suzuki, W. (1987): Comparative ecology of Rubus species (Rosaceae). I. Ecological distribution and life history characteristics of three species, R. palmatus var. coptophyllus, R. microphyllus and R. crataegifolius. – Plant Species Biology 2: 85-100

Tanner, E.V.J. (1977): Four montane forests of Jamaica: a quantitative characterization of the floristics, the soils and the foliar mineral levels, and a discussion of their interrelations. – Journal of Ecology 65: 883-918

Teskey, R.D. and Shrestha, R.B. (1985): A relationship between carbon dioxide, photosynthetic efficiency and shade tolerance. – Physiologia Plantarum 63: 126-132

Thompson, K., Parkinson, J.A., Band, S.R. and Spencer, R.E. (1997): A comparative study of leaf nutrient concentrations in a regional herbaceous flora. – New Phytologist 136: 679-689

Trimble, G.R. and Tryon, E.H (1974): Grapevines a serious obstacle to timber production on good hardwood sites in Appalachia. – Northern Logger and Timber Processor 23 (5): 22-23 (+44)

Uhl, C., Buschbacher, R. and Serrao, E.A.S. (1988): Abandoned pastures in eastern Amazonia. I. Patterns of plant succession. – Journal of Ecology 76: 663-681

Valencia, R., Céron, C., Palcios, W. and Sierra, R. (1999): Las formaciones naturales de la sierra del Ecuador. – In: R. Sierra (ed.): Propuesta preliminar de un sistema de clasificación de vegetación para el Ecuador continental. Proyecto INEFAN/GEF-BIRF y EcoCiencia, Quito, Ecuador Literature 120

Van Bebber, C. (1998): H2O- und CO2-Gaswechsel der Blätter der einheimischen Liane Clematis vitalba in Abhängigkeit von den natürlichen Standortbedingungen im Frühjahr / Frühsommer. – Examina-Thesis at the Institute for Ecological Plant Physiology and Geobotany, University of Düsseldorf

Van Buskirk, J. and Saxer, G. (2001): Delayed costs of an induced defense in Tadpoles? Morphology, hopping, and development rate at metamorphosis. – Evolution 55: 821- 829

Van Daalen, J.C. (1984): Distinguishing features of forest species on nutrient-poor soils in the southern cape. – Bothalia 15: 229-239

Vidal, E., Johns, J., Gerwing J., Barreto, P. and Uhl, C. (1997): Vine management for reduced impact logging in Eastern Amazonia. – Forest Ecology and Management 98: 105-114

Villar, R. and Merino, J. (2001): Comparison of leaf construction costs in woody species with differing leaf life-spans in contrasting ecosystems. – New Phytologist 151(1): 213- 226

Walter, H. and Breckle, S.W. (1991): Bd. 2: Spezielle Ökologie der tropischen und subtropischen Zonen. – In: Ökologie der Erde, 2nd. Edition. Fischer, Stuttgart, D

Waterman, P.G., Ross, J.A.M., Bennett, E.L. and Davies, A.G. (1988): A comparison of the floristics and leaf chemistry of the tree flora in two Malaysian rain forests and the influence of leaf chemistry on populations of colobine monkeys in the Old World. – Biological Journal of the Linnean Society 34: 1-32

Webb, C.O. and Peart, D.R. (2000): Habitat associations of trees and seedlings in an Bornean rain forest. – Journal of Ecology 88: 464-478

Whigham, D. (1984): The influence of vines on the growth of Liquidambar styraciflua L. (sweetgum) – Canadian Journal of Forest Research 14: 37-39

Whitmore, T.C. (1998): A introduction to tropical rain forests – 2nd Editition, Oxford Univ. Press, Oxford, UK

Wilcke, W., Yasin, S., Valarezo, C. and Zech, W. (2001): Change in water quality during the passage through a tropical montane forest. – Biogeochemistry 55: 45-72

Wilcke, W., Yasin, S., Abramowski, U., Valarezo, C. and Zech, W. (2002): Nutrient storage and turnover in organic layers under tropical montane rain forest in Ecuador – European Journal of Soil Science 53: 15-27

Williams-Linera, G. (1990): Vegetation structure and environmental conditions of forest edges in Panama. – Journal of Ecology 78: 356-373 Literature 121

Wilson, K.B., Baldocchi, D.D. and Hanson, P.J. (2001): Leaf age affects the seasonal patterns of photosynthetic capacity and net ecosystem exchange of carbon in a deciduous forest. – Plant Cell and Environment 24: 571-583

Winter, K., Osmond, C.B. and Hubick, K.T. (1986): Crassulacean acid metabolism in the shade. Studies on an epiphytic fern, Pyrrosia longifolia, and other rainforest species from Australia. – Oecologia 68: 224-230

Wright, I.J. and Cannon, K. (2001): Relationships between leaf lifespan and structural defenses in a low-nutrient, sclerophyll flora. – Functional Ecology 15: 351-359

Wright, I.J., Westoby, M. and Reich, P.B. (2002): Convergence towards higher leaf mass per area in dry and nutrient-poor habitats has different consequences for leaf lifespan. – Journal of Ecology 90: 534-543

Appendix 1: Environmental conditions at the sample pairs

Plot Pair No. LAIa DIFNa PFDrel a PFDa PFDref a LAItotal DIFNtotal PFDrel t PFDt PFDref t Index OF 1 0.25 0.85 0.83 44.49 53.60 4.93 0.03 0.04 2.31 54.23 LAI – Leaf are index above the sample OF 2 0.46 0.75 0.82 45.63 55.93 3.42 0.08 0.10 5.47 56.40 a DIFNa – Gap fraction above the sample OF 3 0.25 0.85 0.89 50.43 56.45 2.72 0.15 0.18 10.18 56.45 PFDrel a – Relative photon flux density above the sample OF 4 0.09 0.94 0.96 53.83 56.15 4.84 0.03 0.05 2.67 55.88 -2 -1 PFDa - PFD above sample [µmol m s ] -2 -1 OF 5 0.30 0.80 0.81 45.42 55.74 3.54 0.08 0.09 5.15 55.74 PFDref a – PFD at reference during “a” measurement [µmol m s ] OF 6 0.89 0.54 0.58 30.55 52.60 6.94 0.01 0.03 1.29 51.44 OF 7 0.71 0.59 0.63 34.96 55.58 4.08 0.05 0.06 3.06 55.21 LAItotal – Leaf are index below the sample

OF 8 0.80 0.61 0.86 41.89 48.88 1.92 0.25 0.28 13.66 48.88 DIFNtotal – Gap fraction below the sample

OF 9 0.79 0.62 0.83 39.42 47.59 3.69 0.07 0.07 3.38 46.22 PFDrel t – Relative photon flux density below the sample -2 -1 PFDt – total PFD below sample [µmol m s ] OF 10 0.04 0.97 0.97 52.80 54.52 3.15 0.10 0.08 4.67 55.10 -2 -1 PFDref t – PFD at reference during “below” measurement [µmol m s ] DF 1 5.08 0.03 0.03 2.58 98.03 6.06 0.02 0.01 1.43 96.69 DF 2 6.61 0.01 0.01 1.19 91.48 6.52 0.01 0.01 0.74 91.48 DF 3 5.38 0.03 0.02 2.18 88.87 6.26 0.02 0.01 1.30 88.87 DF 4 5.45 0.02 0.02 1.59 86.22 6.10 0.02 0.01 0.95 84.99 DF 5 5.34 0.02 0.02 1.48 82.93 6.34 0.01 0.01 0.71 82.53 DF 6 5.36 0.03 0.03 2.26 81.37 6.79 0.01 0.01 0.44 80.27 Appendices DF 7 5.20 0.04 0.02 1.83 78.10 6.79 0.01 0.01 0.67 78.10 DF 8 5.10 0.04 0.02 1.84 75.82 6.51 0.01 0.01 0.86 74.54 DF 9 5.30 0.03 0.02 1.50 73.20 7.81 0.01 0.01 0.46 71.89 DF 10 4.40 0.04 0.03 2.11 70.59 8.53 0.00 0.00 0.11 69.41 BF 1 3.50 0.09 0.11 12.09 113.90 5.86 0.03 0.03 3.42 116.50 BF 2 4.06 0.05 0.05 5.79 120.70 5.28 0.03 0.03 3.86 122.70 BF 3 4.19 0.10 0.12 15.58 126.90 6.31 0.02 0.02 2.27 126.90 BF 4 4.35 0.05 0.05 6.44 132.80 5.46 0.03 0.03 3.53 132.80 BF 5 4.57 0.05 0.00 0.14 135.00 5.74 0.02 0.02 3.24 135.30 BF 6 3.59 0.08 0.09 11.83 136.70 5.30 0.02 0.03 3.56 136.80 BF 7 3.15 0.11 0.12 15.33 129.90 3.84 0.06 0.06 7.85 129.90 BF 8 2.98 0.12 0.11 14.22 126.60 4.12 0.06 0.06 7.88 125.10 BF 9 3.69 0.08 0.09 11.40 121.00 4.49 0.04 0.05 5.70 119.60 BF 10 3.41 0.08 0.09 11.09 118.30 4.07 0.05 0.05 6.20 117.10 PF 1 2.65 0.20 0.19 31.61 162.30 4.56 0.05 0.04 6.86 165.00 PF 2 3.48 0.09 0.08 13.33 173.40 5.50 0.03 0.03 4.85 173.40 PF 3 3.32 0.10 0.10 17.71 182.40 5.26 0.03 0.03 5.14 185.20 PF 4 3.09 0.12 0.10 19.45 188.20 5.81 0.02 0.02 4.67 191.20 PF 5 4.18 0.06 0.05 11.93 232.70 4.98 0.04 0.03 6.54 237.50 PF 6 4.00 0.07 0.06 16.23 269.30 5.67 0.02 0.01 3.98 277.60 PF 7 3.65 0.09 0.08 22.92 292.70 4.17 0.06 0.05 13.45 292.70 PF 8 3.63 0.08 0.07 19.66 294.90 4.82 0.04 0.03 8.99 295.60 PF 9 2.83 0.17 0.13 42.72 331.10 4.95 0.04 0.03 10.06 337.10 PF 10 2.67 0.18 0.13 43.09 342.10 5.52 0.03 0.02 8.72 355.60

A

1 App. 1 (page 1/2)

App. 1 (page 2/2)

Plot Pair No. LAIa DIFNa PFDrel a PFDa PFDref a LAItotal DIFNtotal PFDrel t PFDt PFDref t KF 1 0.21 0.87 0.84 150.80 179.30 2.52 0.16 0.23 41.26 176.90 KF 2 1.42 0.40 0.48 82.64 173.20 1.91 0.30 0.31 53.15 173.30 KF 3 1.35 0.38 0.32 53.45 167.80 2.45 0.20 0.23 37.55 163.60 KF 4 1.70 0.34 0.37 63.09 172.70 2.95 0.15 0.18 30.81 172.70 KF 5 0.00 1.00 0.49 85.20 173.30 2.65 0.16 0.18 31.79 173.30 KF 6 2.40 0.21 0.30 53.14 174.40 3.96 0.08 0.09 14.99 174.40 KF 7 0.77 0.58 0.64 111.10 172.70 2.20 0.25 0.20 34.76 172.00 KF 8 0.48 0.71 0.71 121.90 171.90 2.15 0.21 0.26 44.21 172.10 KF 9 1.09 0.46 0.38 65.16 173.10 1.93 0.27 0.28 48.84 173.10 KF 10 1.18 0.43 0.48 82.96 173.40 1.90 0.28 0.30 51.94 173.20

MF I 1 2.00 0.28 0.22 21.05 93.70 4.67 0.04 0.03 2.45 93.70 MF I 2 0.54 0.72 0.58 56.18 97.45 3.58 0.08 0.09 9.39 99.46 MF I 3 0.75 0.59 0.50 50.40 101.50 2.75 0.15 0.17 17.11 101.50 MF I 4 2.10 0.22 0.23 24.70 105.50 3.45 0.08 0.08 9.11 107.50 MF I 5 1.44 0.34 0.26 28.91 109.50 4.01 0.06 0.06 7.01 111.50 MF I 6 0.61 0.66 0.55 62.24 113.80 3.88 0.08 0.07 8.40 115.60 MF I 7 0.97 0.55 0.47 55.55 117.70 4.79 0.03 0.04 4.74 117.70 MF I 8 2.74 0.14 0.15 18.08 122.00 3.74 0.07 0.04 4.46 122.00 MF I 9 1.59 0.38 0.31 38.01 124.30 4.47 0.06 0.05 5.84 126.50 Appendices MF I 10 0.86 0.59 0.46 58.18 127.30 5.08 0.06 0.04 5.50 128.80 MF II 1 1.11 0.45 0.41 20.13 49.45 4.93 0.03 0.03 1.36 50.98 MF II 2 1.26 0.39 0.38 19.80 52.53 3.61 0.07 0.08 4.31 52.53 MF II 3 0.47 0.75 0.76 41.92 55.16 2.51 0.24 0.25 13.97 55.68 MF II 4 0.38 0.75 0.69 39.81 57.56 4.48 0.05 0.08 4.67 57.56 MF II 5 0.51 0.71 0.56 32.84 58.89 3.15 0.11 0.12 7.23 60.58 MF II 6 0.52 0.70 0.82 51.16 62.18 4.39 0.05 0.03 1.58 62.18 MF II 7 1.24 0.40 0.42 27.70 65.49 4.82 0.04 0.06 4.06 65.49 MF II 8 1.47 0.36 0.36 24.49 67.18 8.25 0.00 0.01 0.64 68.91 MF II 9 0.66 0.61 0.62 44.58 72.41 2.89 0.15 0.14 10.44 72.41 MF II 10 0.67 0.63 0.54 40.04 74.44 4.44 0.05 0.06 4.10 74.44 PA 1 0.06 0.96 0.99 352.60 356.90 2.67 0.16 0.43 156.20 367.30 PA 2 0.08 0.94 1.00 372.00 372.50 2.26 0.20 0.18 66.16 376.80 PA 3 0.34 0.78 0.98 370.90 378.90 1.66 0.33 0.54 203.70 375.60 PA 4 0.08 0.94 0.98 368.50 375.60 1.46 0.35 0.54 200.70 374.70 PA 5 0.00 1.00 0.98 367.40 374.70 1.78 0.35 0.43 162.30 380.80 PA 6 0.00 1.00 0.96 370.50 387.10 1.34 0.39 0.63 243.90 390.20 PA 7 0.12 0.91 0.94 371.50 394.60 1.10 0.45 0.63 247.70 394.60 PA 8 0.00 1.00 0.99 395.40 400.30 1.80 0.32 0.50 199.00 400.30 PA 9 0.13 0.90 1.00 412.70 400.40 3.74 0.06 0.11 43.65 403.50 PA 10 0.18 0.86 0.99 398.20 403.10 1.24 0.43 0.71 285.00 403.10

A 2

Appendix 2: Soil-pH and content of exchangeable element on the plots. (Horizon (Hor) 1 is the top raw humus layer, 2 and 3 follow. n.a.: No data available)

pH C N K Ca Mg Mn Al Fe Ca/Al Plot Hor [%] [%] [mg kg-1] [mg kg-1] [mg kg-1] [mg kg-1] [mg kg-1] [mg kg-1] (molar)

1 3.1 20.8 1.1 258.4 695.0 275.7 16.1 277.5 109.8 3.59 OF 2 3.6 4.5 0.2 26.1 11.9 17.4 1.2 736.7 31.0 0.02

3 n.a n.a n.a n.a n.a n.a n.a n.a n.a n.a 1 2.9 37.4 1.5 573.9 656.2 1135.0 85.5 327.1 15.4 2.87 DF 2 2.8 2.7 0.1 21.9 14.3 11.7 1.3 266.5 8.8 0.08 3 n.a n.a n.a n.a n.a n.a n.a n.a n.a n.a 1 2.4 1.8 1.8 296.3 170.7 124.0 10.1 423.0 38.0 0.58 BF 2 2.8 2.9 0.2 22.4 11.3 8.5 0.3 380.3 40.7 0.04 3 n.a n.a n.a n.a n.a n.a n.a n.a n.a n.a Appendices 1 2.6 44.5 1.8 612.8 277.6 199.6 12.1 653.9 59.8 0.61 PF 2 3.1 2.3 0.1 19.8 9.3 10.3 0.7 269.6 44.4 0.05 3 3.4 1.1 0.0 9.6 3.0 4.2 0.3 311.9 32.3 0.01 1 2.8 n.a 1.4 282.1 82.6 178.2 8.9 1074.7 19.1 0.11 KF 2 2.9 4.5 0.3 36.6 10.0 16.2 0.5 91.6 4.5 0.16 3 3.0 0.5 0.1 3.8 6.0 6.0 0.1 40.9 0.7 0.21 1 2.5 39.8 n.a 605.1 188.8 169.5 8.2 450.1 35.3 0.60 MF I 2 3.0 2.7 0.2 48.4 10.3 12.5 0.6 105.1 13.4 0.14 3 n.a n.a n.a n.a n.a n.a n.a n.a n.a n.a 1 2.7 n.a n.a 377.0 142.1 175.3 10.7 323.0 34.0 0.63 MF II 2 3.0 1.9 n.a 29.8 10.3 10.3 0.7 271.8 47.5 0.05 3 n.a n.a n.a n.a n.a n.a n.a n.a n.a n.a PA 1-3 n.a n.a n.a n.a n.a n.a n.a n.a n.a n.a

A 3

Appendix 3: Complete dataset of all collected climber species

2 -2 -2 -1 -2 -1 -1 -1 -1 -1 -1 Plot No. Family Genus Species LA [cm ] LMA [g m ] C [%] Carea [g m ] N [mg g ] Narea [g m ] P [mg g ] K [mg g ] Ca [mg g ] Mg [mg g ] Mn [mg g ] Al [mg g ] OF 1 Dioscoraceae Dioscorea sp. 43.9 55.7 44.61 24.869 30.20 1.68 1.52 29.77 4.58 3.41 0.35 0.02 OF 2 Liliaceae Smilax mollis 54.0 96.2 43.05 41.404 22.02 2.12 1.81 24.39 1.73 1.19 0.15 0.06 OF 3 Malpighiaceae n.i. n.i. 20.5 130.4 43.37 56.571 10.64 1.39 0.63 13.12 14.71 4.53 1.98 0.01 OF 4 Malpighiaceae n.i. n.i. 31.6 120.0 44.26 53.092 16.15 1.94 0.82 15.29 16.30 3.24 1.71 0.04 OF 5 Poaceae Chusquea dombeyana 5.3 62.0 44.32 27.493 20.38 1.26 1.04 11.59 1.91 0.92 0.56 0.04 OF 6 Polygonaceae Muehlenbeckia tamnifolia 1.4 64.7 45.99 29.743 18.47 1.19 1.20 16.58 4.79 3.68 2.22 0.32 OF 7 Valerianaceae Valeriana clematitis 9.9 57.3 42.71 24.473 20.00 1.15 1.55 22.81 17.33 6.22 0.12 0.16

OF 8 Valerianaceae Valeriana laurifolia 17.0 81.2 45.45 36.894 15.28 1.24 1.52 24.09 11.65 5.98 0.56 0.02

OF 9 Valerianaceae Valeriana laurifolia 9.5 89.6 42.78 38.322 14.94 1.34 1.24 20.53 7.24 5.35 0.08 0.02 OF 10 Polygonaceae Muehlenbeckia tamnifolia 1.3 75.9 45.77 34.733 20.19 1.53 0.98 13.08 14.79 5.45 2.14 0.60 DF 1x Asteraceae Pentacalia sp. 19.2 51.4 42.75 21.958 15.40 0.79 0.81 16.89 5.31 7.06 0.95 0.08 DF 1y Asteraceae Pentacalia sp. 33.6 44.0 44.23 19.480 16.21 0.71 0.85 48.99 6.36 5.99 0.23 0.08 DF 2 Ericaceae Orthaea sp. 35.6 86.8 39.4 34.205 10.69 0.93 0.42 5.31 4.91 1.57 0.30 0.09 DF 3x Asclepiadaceae Gonioanthela sp. 24.0 38.8 39.3 15.265 21.08 0.82 0.88 33.79 9.42 6.51 1.26 0.07 DF 3y Ampelidaceae Cissus sp. 23.0 45.8 39.73 18.183 12.55 0.57 0.65 15.40 12.18 6.42 0.85 0.38 DF 4 Alstomeriaceae Bomarea sp. 12.7 40.6 36.14 14.670 23.87 0.97 1.44 47.40 4.12 4.78 1.00 0.08 Appendices DF 5 Melastomataceae Topobea sp. 15.5 93.5 43.68 40.848 11.84 1.11 0.73 17.02 14.09 9.00 0.99 0.19 DF 6 Asteraceae Mikania sp. 10.8 53.1 41.65 22.107 16.31 0.87 0.92 27.23 8.86 4.66 1.38 0.12 DF 7 Alstomeriaceae Bomarea sp. 10.5 45.2 41.46 18.721 6.92 0.31 0.94 47.55 5.67 4.24 1.28 0.12 DF 8 Asteraceae Mikania szyszylowiczii 11.9 71.8 41.21 29.598 11.66 0.84 0.56 39.87 4.96 5.19 0.61 0.14 DF 9 Alstomeriaceae Bomarea sp. 50.7 52.1 43.34 22.585 18.99 0.99 0.71 28.17 8.51 5.20 2.54 0.20 DF 10 Alstomeriaceae Bomarea sp. 24.8 51.2 42.6 21.813 19.75 1.01 0.83 30.88 8.46 5.20 2.41 0.12 BF 1 Asteraceae Mikania szyszylowiczii 15.8 111.9 41.54 46.494 10.26 1.15 0.60 41.22 6.05 6.08 0.69 0.16 BF 2 Asteraceae Mikania szyszylowiczii 19.9 90.6 42.02 38.079 11.39 1.03 0.46 29.97 6.52 6.82 1.04 0.09 BF 3 Ampelidaceae Cissus sp. 8.8 52.3 43.49 22.759 9.04 0.47 0.51 14.82 4.58 3.52 0.32 0.03 BF 4 Asteraceae Pentacalia sp. 49.7 64.8 43.01 27.881 15.66 1.02 0.82 14.12 8.17 7.51 0.62 0.06 BF 5 Melastomataceae Topobea sp. 45.8 94.6 42.39 40.083 9.46 0.89 0.43 17.30 11.08 5.99 0.95 0.08 BF 6 Poaceae Chusquea dombeyana 3.1 31.4 43.65 13.724 18.97 0.60 0.68 19.73 1.80 1.77 0.07 0.02 BF 7 Asteraceae Pentacalia sp. 7.5 49.2 39.62 19.481 13.97 0.69 0.73 19.88 5.90 5.40 0.35 0.06 BF 8 Poaceae Chusquea dombeyana 17.4 87.1 46.54 40.534 20.33 1.77 0.70 13.74 1.90 1.00 0.12 0.08 BF 9 Asteraceae Pentacalia sp. 20.8 74.0 49.83 36.893 14.82 1.10 0.71 15.84 6.35 5.60 0.15 0.08 BF 10 Asteraceae Pentacalia sp. 17.1 64.0 40.03 25.639 13.81 0.88 0.74 16.19 5.10 4.99 0.25 0.01 PF 1 Asteraceae n.i. n.i. 18.4 87.0 42.26 36.767 16.82 1.46 0.80 17.84 6.85 3.61 0.48 0.01 PF 2 Amaryllidaceae Bomarea sp. 19.3 79.3 44.69 35.452 12.68 1.01 0.58 10.35 4.12 2.05 1.09 0.05 PF 3 Dioscoraceae Dioscorea sp. 17.3 40.2 46.6 18.718 14.49 0.58 0.52 14.16 12.26 4.83 1.56 0.03 PF 4 Liliaceae Smilax sp. 24.1 78.7 46.82 36.848 11.94 0.94 0.34 6.90 5.22 2.77 0.75 0.10 PF 5 Poaceae Chusquea dombeyana 7.8 45.4 42.97 19.520 18.81 0.85 0.60 11.26 3.94 1.15 0.60 0.49 PF 6 Asteraceae Mikania szyszylowiczii 7.7 77.0 40.7 31.326 8.30 0.64 0.55 25.07 4.89 6.04 0.34 0.00 PF 7 Poaceae Chusquea dombeyana 7.3 50.8 43.27 21.994 18.19 0.92 0.55 13.08 1.22 0.82 0.10 0.14 PF 8 Poaceae Chusquea dombeyana 4.5 45.6 43.17 19.697 19.88 0.91 0.67 17.94 1.50 0.85 0.34 0.03 PF 9 Poaceae Chusquea dombeyana 16.4 93.1 42.89 39.952 12.98 1.21 0.72 16.29 1.77 0.90 0.26 0.07 PF 10 n.i. n.i. n.i. 15.9 72.6 44.58 32.347 14.87 1.08 0.78 26.09 2.79 2.96 1.69 0.11

A

4 App. 3 (page 1/2)

App. 3 (page 2/2)

2 -2 -2 -1 -2 -1 -1 -1 -1 -1 -1 Plot No. Family Genus Species LA [cm ] LMA [g m ] C [%] Carea [g m ] N [mg g ] Narea [g m ] P [mg g ] K [mg g ] Ca [mg g ] Mg [mg g ] Mn [mg g ] Al [mg g ] KF 1 Liliaceae Smilax sp. 24.8 156.7 48.51 76.014 7.39 1.16 0.56 10.92 1.13 1.06 0.13 0.03 KF 2 Myrsinaceae Myrsine andina 6.7 97.1 51.43 49.945 11.21 1.09 0.89 10.32 2.31 1.59 0.13 0.08 KF 3 Asclepiadaceae Asclepias ditasa 3.5 93.9 47.96 45.037 19.05 1.79 0.88 12.35 9.69 4.22 1.76 0.04 KF 4 Asclepiadaceae Asclepias ditasa 5.1 93.7 45.71 42.814 13.72 1.29 0.68 12.54 10.48 2.89 1.17 0.05 KF 5 Asclepiadaceae Asclepias ditasa 5.3 119.7 47.4 56.725 15.16 1.81 0.77 11.18 8.16 3.18 0.85 0.03 KF 6 Liliaceae Smilax sp. 19.9 127.2 45.27 57.591 13.88 1.77 0.45 10.43 2.19 2.29 0.14 0.02 KF 7 Liliaceae Smilax sp. 16.8 111.8 47.06 52.618 12.96 1.45 0.39 14.08 1.71 0.93 0.24 0.01 KF 8 Liliaceae Smilax sp. 28.2 145.7 46.16 67.270 16.67 2.43 0.51 9.74 2.23 2.54 0.22 0.03 KF 9 Asclepiadaceae Asclepias ditasa 4.4 154.4 47.91 73.995 12.07 1.86 0.60 15.47 6.94 3.43 0.89 0.05 KF 10 Asclepiadaceae Asclepias ditasa 7.0 131.9 47.1 62.135 13.14 1.73 0.48 13.79 6.23 4.10 0.81 0.09

MF I 1 Poaceae Chusquea dombeyana 4.5 54.4 40.42 21.994 21.19 1.15 0.44 8.30 2.10 0.62 0.28 0.14 MF I 2 Malpighiaceae Banisteriopsis sp. 39.6 116.3 42.41 49.315 10.89 1.27 0.69 20.75 11.88 3.78 0.64 0.07 MF I 3 Malpighiaceae Banisteriopsis sp. 31.2 147.7 42.35 62.552 10.41 1.54 0.55 16.44 11.04 4.79 0.70 0.07 MF I 4 Alstomeriaceae Bomarea sp. 6.7 54.4 45.16 24.583 19.98 1.09 0.89 16.51 1.47 1.62 0.16 0.09 MF I 5 Poaceae Chusquea dombeyana 10.1 63.3 43.99 27.836 23.36 1.48 0.87 6.95 1.42 0.55 0.11 0.15 MF I 6 Poaceae Chusquea dombeyana 15.2 80.1 40.45 32.411 21.71 1.74 0.85 8.30 2.02 0.80 0.14 0.33 MF I 7 Poaceae Chusquea dombeyana 16.9 75.1 41.07 30.864 23.01 1.73 0.93 9.11 1.64 0.57 0.11 0.06 MF I 8 Dioscoraceae Dioscorea sp. 18.5 102.5 40.07 41.061 17.13 1.76 0.70 18.13 18.34 12.63 1.81 0.12 MF I 9 Dioscoraceae Dioscorea sp. 0.4 35.9 44.32 15.897 31.05 1.11 1.22 17.46 4.18 2.74 1.80 0.17 Appendices MF I 10 Asteraceae Pentacalia lanceolofolia 48.2 142.1 40.24 57.169 13.13 1.87 0.73 19.73 6.92 4.54 0.40 0.05 MF II 1 Alstomeriaceae Bomarea sp. 26.0 52.9 43.09 22.796 26.89 1.42 2.50 24.01 1.52 1.89 0.25 0.03 MF II 2 Alstomeriaceae Bomarea sp. 22.9 155.2 47.71 74.028 12.69 1.97 0.77 16.06 4.45 2.08 1.24 0.06 MF II 3 Liliaceae Smilax sp. 25.3 134.5 42.09 56.622 13.65 1.84 0.69 19.28 6.38 11.17 1.17 0.07 MF II 4x Alstomeriaceae Bomarea sp. 23.5 144.9 46.51 67.406 11.78 1.71 0.74 10.23 2.21 2.87 0.33 0.05 MF II 4y Dioscoraceae Dioscorea sp. 15.1 144.1 47.4 68.297 13.55 1.95 0.49 9.37 3.68 3.22 0.42 0.03 MF II 5 Liliaceae Smilax sp. 28.4 145.2 44.33 64.370 11.34 1.65 0.55 23.87 2.03 2.36 0.21 0.02 MF II 6 Asteraceae Mikania szyszylowiczii 21.9 160.8 42.73 68.702 7.89 1.27 0.34 11.27 4.11 4.46 0.64 0.06 MF II 7 Liliaceae Smilax sp. 23.1 98.1 45.18 44.318 15.30 1.50 0.81 15.30 3.27 1.68 0.18 0.02 MF II 8 Liliaceae Smilax sp. 10.8 103.2 46.56 48.053 11.90 1.23 0.29 12.25 2.91 2.73 0.20 0.03 MF II 9 Asteraceae Mikania n.i. 28.5 131.0 48.46 63.461 12.06 1.58 0.46 7.44 2.20 2.65 0.20 0.05 MF II 10 Liliaceae Smilax sp. 16.7 123.9 48.52 60.107 13.78 1.71 0.42 9.50 5.99 2.38 0.33 0.04 PA 1 Liliaceae Smilax sp. 19.3 189.9 43.9 83.349 15.06 2.86 0.37 10.36 13.95 1.68 0.54 0.08 PA 2 Liliaceae Smilax sp. 14.7 108.7 47.18 51.288 18.21 1.98 0.77 16.70 8.52 2.31 0.25 0.12 PA 3 Liliaceae Smilax sp. 21.8 120.2 43.52 52.297 14.34 1.72 0.77 20.53 5.19 5.90 0.06 0.09 PA 4 Poaceae Chusquea dombeyana 6.0 77.2 44.64 34.452 24.70 1.91 0.57 11.08 2.28 0.67 0.19 0.01 PA 5 Liliaceae Smilax sp. 15.4 162.0 46.1 74.660 13.68 2.22 0.39 8.85 9.75 2.33 0.18 0.03 PA 6 Liliaceae Smilax sp. 27.1 176.0 45.16 79.498 12.49 2.20 0.34 9.07 14.90 2.25 0.28 0.03 PA 7 Poaceae Chusquea dombeyana 4.9 75.4 46.64 35.157 23.82 1.80 0.56 11.15 2.76 0.75 0.24 0.05 PA 8 Liliaceae Smilax sp. 18.2 180.5 46.71 84.334 14.26 2.58 0.38 9.56 10.82 1.54 0.08 0.05 PA 9 Liliaceae Smilax sp. 10.9 161.0 47.32 76.162 13.19 2.12 0.63 8.84 9.94 1.43 0.07 0.07 PA 10 Liliaceae Smilax sp. 15.7 116.5 46.38 54.022 17.26 2.01 0.67 15.58 6.99 1.25 0.10 0.09

A 5

Appendix 4: Complete dataset of all collected supporter species

2 -2 -2 -1 -2 -1 -1 -1 -1 -1 -1 Plot No. Family Genus Species LA [cm ] LMA [g m ] C [%] Carea [g m ] N [mg g ] Narea [g m ] P [mg g ] K [mg g ] Ca [mg g ] Mg [mg g ] Mn [mg g ] Al [mg g ] OF 1 Asteraceae Ageratina dendroides 25.8 109.7 46.01 50.484 15.78 1.73 1.02 16.06 7.77 3.33 0.87 0.01 OF 2 Asteraceae Ageratina dendroides 23.3 92.7 47.92 44.444 19.12 1.77 1.19 25.34 5.96 2.31 1.07 0.05 OF 3 Rubiaceae Palicurea sp. 12.3 91.4 42.09 38.475 17.40 1.59 0.83 15.24 7.20 2.03 0.92 9.34 OF 4 Lauraceae Persea nectandra 19.0 99.4 46.91 46.641 12.19 1.21 0.69 7.36 4.96 1.77 0.55 0.04 OF 5 Asteraceae Ageratina dendroides 22.2 93.5 48.46 45.333 16.71 1.56 2.03 26.34 9.75 4.57 1.74 0.03 OF 6 Piperaceae Piper sp. 154.9 89.5 46.39 41.542 35.27 3.16 1.19 31.25 4.32 5.65 1.64 0.09 OF 7 Caprifoliaceae Viburnum sp. 45.3 160.4 49.65 79.660 13.73 2.20 0.85 13.27 11.48 5.01 1.60 0.72

OF 8 Asteraceae Ageratina dendroides 28.1 101.8 48.16 49.022 15.51 1.58 1.35 14.65 7.14 2.08 2.38 0.06

OF 9 Asteraceae Ageratina dendroides 33.7 103.2 43.17 44.546 16.36 1.69 1.15 18.92 3.90 2.12 0.83 0.05 OF 10 Asteraceae Ageratina dendroides 18.8 176.4 43.84 77.345 15.20 2.68 1.06 16.56 9.10 3.69 0.90 0.02 DF 1 Melastomataceae n.i. n.i. 41.2 87.5 39.26 34.368 10.38 0.91 0.70 6.64 23.35 2.99 1.96 2.22 DF 1 Melastomataceae n.i. n.i. 41.2 87.5 39.26 34.368 10.38 0.91 0.70 6.64 23.35 2.99 1.96 2.22 DF 2 Clusiaceae Clusia sp. 89.0 141.9 45.83 65.038 11.89 1.69 0.49 6.93 11.04 5.11 0.09 0.07 DF 3 Melastomataceae n.i. n.i. 82.1 78.3 44.19 34.598 21.04 1.65 0.85 17.39 4.22 6.11 0.15 3.77 DF 3 Melastomataceae n.i. n.i. 82.1 78.3 44.19 34.598 21.04 1.65 0.85 17.39 4.22 6.11 0.15 3.77 DF 4 Arecaceae Dictyocarium sp. 74.0 66.7 40.99 27.340 17.81 1.19 1.22 9.88 3.10 3.43 0.54 0.03 Appendices DF 5 Melastomataceae n.i. n.i. 52.9 88.0 38.7 34.075 11.90 1.05 0.48 12.98 34.31 3.07 2.47 8.94 DF 6 Melastomataceae n.i. n.i. 119.5 82.6 46.53 38.423 6.70 0.55 0.50 18.35 3.38 5.02 0.11 6.10 DF 7 Clusiaceae Clusia sp. 95.5 154.2 45.33 69.920 11.67 1.80 0.40 10.01 6.85 4.69 0.02 0.01 DF 8 Alzateaceae Alzatea sp. 39.6 164.5 45.92 75.535 7.70 1.27 0.63 15.55 4.39 2.28 0.44 0.14 DF 9 n.i. n.i. n.i. 30.8 117.4 45.22 53.098 11.00 1.29 0.23 11.72 16.81 7.56 2.07 0.26 DF 10 Melastomataceae n.i. n.i. 19.6 78.2 42.79 33.458 15.54 1.22 0.52 10.35 11.87 6.44 0.38 1.38 BF 1 Asteraceae Pentacalia lanceolifolia 21.3 65.8 41.87 27.547 16.27 1.07 0.92 9.30 4.50 0.13 0.13 0.15 BF 2 Clusiaceae Clusia elliptica 6.4 120.3 48.56 58.423 10.77 1.30 0.41 7.22 4.88 3.20 0.38 0.14 BF 3 Lauraceae n.i. n.i. 33.6 110.5 48.17 53.239 11.75 1.30 0.40 15.54 3.50 5.03 0.05 0.05 BF 4 n.i. n.i. n.i. 46.4 143.8 44.85 64.484 9.86 1.42 0.28 7.99 2.63 2.08 0.10 2.16 BF 5 n.i. n.i. n.i. 67.2 92.1 44.66 41.136 12.40 1.14 0.70 31.10 3.38 2.43 0.10 0.03 BF 6 Lauraceae n.i. n.i. 57.7 112.5 51.78 58.278 12.84 1.45 0.48 10.13 2.72 1.53 0.12 0.19 BF 7 Lauraceae n.i. n.i. 39.6 127.6 45.26 57.747 13.34 1.70 0.38 9.69 13.87 5.08 0.61 0.06 BF 8 Ericaceae n.i. n.i. 37.3 316.3 48.07 152.022 9.89 3.13 0.38 8.29 2.97 1.82 0.02 0.09 BF 9 Araliaceae Schefflera sp. 23.1 137.5 48.65 66.906 11.56 1.59 0.51 10.40 6.00 3.40 0.81 0.12 BF 10 Araliaceae Schefflera sp. 13.9 111.3 47.32 52.683 12.24 1.36 0.60 13.09 5.67 3.63 0.82 0.11 PF 1 Lauraceae n.i. n.i. 88.3 131.5 46.04 60.543 14.94 1.96 0.50 14.07 1.93 1.45 0.17 0.04 PF 2 Lauraceae Persea sp. 15.2 131.4 42.79 56.218 11.25 1.48 0.33 16.81 5.33 1.35 0.14 0.22 PF 3 Ericaceae n.i. n.i. 90.2 117.8 46.74 55.046 7.89 0.93 0.19 6.97 4.18 1.76 0.16 0.02 PF 4 Gentianaceae Macrocarpaea sodiroaua 61.5 113.2 42.83 48.490 10.32 1.17 0.28 7.21 17.44 3.36 0.29 8.85 PF 5 Myrtacaceae Eugenia sp. 21.9 135.0 45.24 61.055 11.76 1.59 0.26 6.70 1.85 1.64 0.14 0.11 PF 6 Gentianaceae Macrocarpaea sodiroaua 133.4 101.3 42.63 43.167 12.38 1.25 0.36 64.00 16.95 3.12 0.16 15.73 PF 7 Lauraceae n.i. n.i. 27.7 137.9 38.92 53.676 12.70 1.75 0.60 41.34 6.88 6.24 0.55 0.09 PF 8 Araliaceae Schefflera sp. 5.7 91.7 48.56 44.545 14.46 1.33 0.64 23.13 4.24 1.82 0.19 0.09 PF 9 Myrtacaceae Eugenia sp. 11.5 143.4 42.17 60.491 15.12 2.17 0.44 19.05 4.85 1.87 0.28 0.07 PF 10 n.i. n.i. n.i. 32.2 152.7 41.64 63.602 15.03 2.30 0.49 11.93 9.79 4.06 1.21 0.10

A

6

App. 4 (page 1/2)

App. 4 (page 2/2)

2 -2 -2 -1 -2 -1 -1 -1 -1 -1 -1 Plot No. Family Genus Species LA [cm ] LMA [g m ] C [%] Carea [g m ] N [mg g ] Narea [g m ] P [mg g ] K [mg g ] Ca [mg g ] Mg [mg g ] Mn [mg g ] Al [mg g ] KF 1 Asteraceae Baccharis macrantha 2.1 131.4 48.86 64.182 13.89 1.82 0.55 12.17 1.76 1.76 0.40 0.06 KF 2 n.i. n.i. n.i. 16.8 204.9 47.73 97.810 15.95 3.27 0.42 15.39 1.39 2.70 0.46 0.19 KF 3 Cyrillaceae Purdiaea nutans 9.6 157.9 48.65 76.812 15.69 2.48 0.33 14.58 4.33 2.73 0.47 0.08 KF 4 Clusiaceae Clusia multiflora 43.1 369.9 46.57 172.278 7.61 2.81 0.24 5.04 5.69 1.36 0.60 0.01 KF 5 Ericaceae Befaria aestuans 6.4 204.7 47.14 96.499 10.06 2.06 0.25 5.36 2.79 2.44 0.16 0.07 KF 6 Myrsinaceae Cybianthus marginatus 3.7 126.4 48.23 60.942 10.34 1.31 0.46 14.31 2.52 1.87 0.46 0.03 KF 7 Clusiaceae Clusia elliptica 6.7 214.3 50.12 107.387 10.65 2.28 0.35 8.30 2.25 1.89 0.31 0.03 KF 8 Ericaceae Befaria aestuans 6.3 183.5 51.82 95.065 12.15 2.23 0.33 7.19 1.92 1.73 0.25 0.06 KF 9 Cyrillaceae Purdiaea nutans 15.1 169.1 45.73 77.352 13.09 2.21 0.13 0.71 0.23 0.04 0.03 0.08 KF 10 Asteraceae Baccharis macrantha 4.2 119.9 49.74 59.618 14.67 1.76 0.53 20.08 1.27 1.21 0.23 0.05

MF I 1 Melastomataceae Miconia media 18.5 142.5 43.04 61.351 9.43 1.34 0.51 14.21 12.53 1.21 1.22 9.02 MF I 2 Cyrillaceae Purdiaea nutans 9.7 166.3 48.65 80.914 9.92 1.65 0.34 11.59 6.48 2.58 0.53 0.06 MF I 3 Melastomataceae Miconia riveti 105.0 210.7 48.2 101.534 8.81 1.86 0.42 9.13 2.29 3.25 0.19 3.39 MF I 4 Myrsinaceae Myrsine sp. 26.4 129.1 47.16 60.880 10.29 1.33 0.44 17.09 5.73 1.64 0.16 0.10 MF I 5 Rubiaceae n.i. n.i. 14.3 128.9 44.14 56.917 12.03 1.55 0.42 10.57 5.87 4.06 0.17 3.37 MF I 6 Gentianaceae Macrocarpaea sodiroaua 244.9 124.8 45.63 56.944 18.73 2.34 1.10 6.39 3.10 3.66 0.11 0.19 MF I 7 Melastomataceae Graffenrieda emarginata 23.8 261.0 44.56 116.295 7.57 1.98 0.23 7.46 8.62 2.54 0.17 0.10 MF I 8 n.i. n.i. n.i. 13.1 169.9 42.8 72.701 10.62 1.80 0.40 6.12 2.03 1.78 0.20 0.08 MF I 9 Rubiaceae n.i. n.i. 14.3 92.5 44.1 40.792 18.90 1.75 0.80 9.08 3.47 3.35 0.18 3.11 Appendices MF I 10 Clusiaceae Clusia elliptica 5.6 234.8 45.24 106.237 9.83 2.31 0.40 8.80 3.25 1.98 0.30 0.08 MF II 1 Clusiaceae Clusia elliptica 13.3 154.5 42.65 65.908 7.20 1.11 0.49 10.77 15.71 1.94 1.91 1.92 MF II 2 Melastomataceae Miconia media 6.6 191.5 46.04 88.183 9.91 1.90 0.57 10.69 4.40 2.41 0.39 0.02 MF II 3 Lauraceae Persea sp. 15.9 150.0 49.12 73.676 18.11 2.72 0.75 9.56 1.19 2.93 0.15 0.21 MF II 4 Clusiaceae Clusia elliptica 30.5 360.7 47.65 171.863 6.49 2.34 0.29 4.86 12.88 4.82 0.90 0.03 MF II 4 Clusiaceae Clusia elliptica 30.5 360.7 47.65 171.863 6.49 2.34 0.29 4.86 12.88 4.82 0.90 0.03 MF II 5 Cunoniaceae Weinmannia sp. 11.5 190.0 49.04 93.200 9.78 1.86 0.33 5.47 2.48 1.75 0.15 2.34 MF II 6 Lauraceae Persea sp. 18.7 217.3 48.61 105.611 15.72 3.42 0.62 7.16 2.43 2.99 0.17 0.17 MF II 7 Lauraceae n.i. n.i. 8.4 204.9 49.56 101.559 10.65 2.18 0.34 8.95 1.89 1.84 0.09 0.12 MF II 8 Cyrillaceae Purdiaea nutans 11.3 160.8 45.7 73.466 9.74 1.57 0.20 11.47 9.24 2.79 1.03 0.08 MF II 9 Clusiaceae Clusia multiflora 73.4 394.0 55.69 219.422 7.14 2.81 0.18 3.49 11.42 1.87 0.67 0.01 MF II 10 n.i. n.i. n.i. 10.7 143.9 42.76 61.537 21.09 3.04 0.94 16.05 8.29 3.41 1.15 0.05 PA 1 Ericaceae Befaria aestuans 4.2 216.6 49.92 108.143 9.68 2.10 0.13 4.53 12.46 2.18 0.58 0.10 PA 2 Ericaceae Gauteria foliolata 1.2 256.6 51.52 132.190 9.92 2.54 0.18 9.82 4.44 1.23 0.19 0.12 PA 3 Ericaceae Vaxinium sp. 3.0 286.0 51.77 148.073 7.29 2.09 0.14 4.89 7.26 5.50 0.94 0.28 PA 4 Ericaceae Gauteria foliolata 2.5 223.2 49.56 110.624 8.50 1.90 0.18 8.44 4.93 3.45 0.72 0.11 PA 5 Ericaceae Vaccinium sp. 3.1 303.2 52.73 159.869 7.42 2.25 0.12 4.36 6.62 3.90 0.80 0.10 PA 6 Ericaceae Vaccinium floribundum 2.3 259.8 45.91 119.280 7.13 1.85 0.13 8.01 7.28 4.50 1.50 0.29 PA 7 n.i. n.i. n.i. 8.0 212.7 47.72 101.479 9.76 2.08 0.26 14.81 6.21 2.88 0.89 0.06 PA 8 Lauraceae Persea nectandra 41.0 353.8 46.4 164.168 9.03 3.19 0.21 7.92 8.97 2.87 0.11 2.56 PA 9 Melastomataceae n.i. n.i. 9.5 188.3 43.61 82.111 9.53 1.79 0.35 12.52 19.12 1.07 1.67 7.88 PA 10 Ericaceae Vaccinium floribundum 1.4 257.7 51.06 131.604 8.15 2.10 0.17 7.36 5.07 3.46 1.27 0.07

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Appendix 5: Mature and young leaves dataset mature young

-2 -1 -2 -2 -1 -2 Growth form PLOT No. GENUS TRIBE SPECIES LA LMA [g m ] Nmass [mg g ] Narea [mg m ] C [%] LA LMA [g m ] Nmass [mg g ] Narea [mg m ] C [%] Climber OF 1 Dioscoraceae n.i. n.i. 17565 55.75 30.20 1683.50 44.61 1769.11 42.78 27.61 1181.15 46.95 Climber OF 2 Smilacac Smilax mollis 16190 96.18 22.02 2117.60 43.05 2299.53 89.89 30.65 2755.14 47.93 Climber OF 3 Malphigiaceae n.i. n.i. 8184.7 130.44 10.64 1388.08 43.37 1877.17 87.45 15.88 1389.18 45.63 Climber OF 4 Malphigiaceae n.i. n.i. 15775 119.96 16.15 1937.74 44.26 1091.20 83.59 14.31 1195.76 48.22 Climber DF 2 Ericaceae n.i. n.i. 15547 86.81 10.69 928.43 39.40 1922.90 26.14 17.57 459.32 41.13 Climber DF 6 Asteraceae n.i. n.i. 19850 53.08 16.31 865.60 41.65 1507.67 40.71 15.92 648.31 47.54 Climber DF 10 Alstomeriaceae Bomarea sp. 27548 51.21 19.75 1011.06 42.60 383.61 30.08 41.55 1250.01 43.13

Climber BF 4 Asteraceae n.i. n.i. 19866 64.82 15.66 1015.07 43.01 1549.38 54.23 13.56 735.49 44.00 Climber PF 1 Asteraceae n.i. n.i. 14695 87.00 16.82 1463.58 42.26 1863.70 57.67 18.79 1083.47 42.83 Climber KF 3 Asclepiadacea Ascleps ditasa 4239.4 93.90 19.05 1789.27 47.96 225.65 68.80 8.63 593.76 47.75 Climber MF I 3 Malphigiaceae n.i. n.i. 12490 147.70 10.41 1538.06 42.35 1015.40 79.23 1.66 131.40 43.80 Climber MF II 1 Alstomeriaceae Bomarea sp. 12984 52.90 26.89 1422.59 43.09 614.83 46.92 45.12 Climber MF II 3 Liliaceae Smilax sp. 20205 134.53 13.65 1835.64 42.09 645.45 69.28 21.71 1503.84 45.13 Climber MF II 9 Asteraceae n.i. n.i. 18827 130.96 12.06 1579.25 48.46 1460.35 107.53 13.90 1494.94 48.21 Climber PA 1 Liliaceae Smilax sp. 9642.8 189.86 15.06 2860.11 43.90 944.28 64.14 29.91 1918.50 43.96 Climber PA 10 Liliaceae Smilax sp. 11022 116.48 17.26 2009.97 46.38 585.32 63.97 8.81 563.68 47.20 Appendices Tree OF 1 Asteraceae Ageratina dendroides 20642 109.72 15.78 1731.90 46.01 1091.45 89.71 21.30 1911.27 52.56 Tree OF 7 Caprifoliaceae Viburnum sp. 22633 160.44 13.73 2202.15 49.65 2530.00 148.42 15.81 2347.22 47.46 Tree DF 2 Clusiaceae Clusia sp. 26707 141.91 11.89 1686.67 45.83 1823.63 62.14 24.44 1519.04 45.37 Tree DF 5 Melastomataceae n.i. n.i. 31753 88.05 11.90 1047.53 38.70 3702.25 91.51 14.67 1342.06 38.43 Tree DF 6 Melastomataceae n.i. n.i. 35849 82.58 6.70 553.26 46.53 4020.33 77.66 9.05 702.52 45.34 Tree DF 7 Clusiaceae Clusia sp. 38204 154.25 11.67 1799.53 45.33 5734.50 73.95 18.77 1387.89 57.28 Tree DF 8 Alzatea sp. 15859 164.49 7.70 1266.60 45.92 8464.00 70.34 12.55 882.90 42.08 Tree DF 9 n.i. n.i. n.i. 18488 117.42 11.00 1292.23 45.22 2254.60 79.13 10.96 867.34 35.99 Tree DF 10 Melastomataceae n.i. n.i. 19561 78.19 15.54 1215.09 42.79 638.40 73.44 17.29 1270.10 42.07 Tree BF 2 Clusiaceae Clusia elliptica 10182 120.31 10.77 1295.65 48.56 722.29 110.99 10.08 1118.95 43.22 Tree BF 3 Lauraceae n.i. n.i. 23486.3 110.52 11.75 1298.36 48.17 2116.86 99.62 10.91 1086.71 48.62 Tree BF 4 n.i. n.i. n.i. 41804 143.78 9.86 1417.79 44.85 3113.33 74.11 17.06 1264.21 47.46 Tree BF 6 Lauraceae n.i. n.i. 40394 112.55 12.84 1445.15 51.78 4056.00 82.84 15.99 1324.52 50.44 Tree BF 9 Araliaceae Schefflera sp. 18486 137.53 11.56 1589.58 48.65 1361.30 102.17 12.71 1299.10 45.35 Tree BF 10 Araliaceae Schefflera sp. 16721 111.33 12.24 1363.09 47.32 824.81 58.15 21.14 1229.54 50.92 Tree PF 2 Lauraceae Persea sp. 22841 131.38 11.25 1478.05 42.79 1233.20 113.60 12.12 1376.75 40.26 Tree KF 1 Asteraceae Baccharis macrantha 6393.9 131.36 13.89 1824.58 48.86 104.69 96.67 16.84 1627.81 50.82 Tree KF 5 Ericaceae Befaria estuans 9583.9 204.71 10.06 2059.17 47.14 399.78 91.92 13.95 1281.81 49.51 Tree MF I 5 Rubiaceae n.i. n.i. 11459 128.95 12.03 1550.85 44.14 1482.43 64.57 18.93 1222.54 43.32 Tree MF I 6 Gentianaceae Macrocarpea sodiroaua 73465 124.80 18.73 2337.84 45.63 4017.30 122.21 25.19 3079.03 42.73 Tree MF I 7 Melastomataceae Graffenrieda emaginata 14284 260.98 7.57 1975.99 44.56 1094.50 60.00 13.50 810.15 43.16 Tree MF II 1 Clusiaceae Clusia elliptica 18670 154.53 7.20 1112.41 42.65 724.02 158.97 9.45 1502.91 49.63 Tree MF II 2 Melastomataceae Miconia media 11213 191.54 9.91 1898.65 46.04 370.42 136.58 8.09 1104.84 41.62 Tree MF II 6 Lauraceae Persea sp. 18707 217.26 15.72 3415.60 48.61 278.96 123.95 35.78 4435.60 46.44 Tree MF II 8 Cyrillaceae Pudria nutans 14719 160.76 9.74 1566.03 45.70 472.07 98.90 10.58 1046.31 46.29 Tree MF II 9 Clusiaceae Clusia multiflora 36717 394.01 7.14 2814.88 55.69 1852.60 96.63 20.10 1942.32 49.27 Tree PA 6 Ericaceae Vaxinium floribundum 6509.3 259.81 7.13 1853.01 45.91 201.76 168.22 9.75 1639.35 48.41 A

Tree PA 7 n.i. n.i. n.i. 12066 212.66 9.76 2075.72 47.72 756.03 166.75 12.83 2139.17 46.01 8

Tree PA 10 Ericaceae Vaxinium floribundum 4145.6 257.74 8.15 2101.64 51.06 84.39 197.03 35.09 6914.72 45.62

Appendix 6: Mean leaf structure parameters (Standard deviation in brackets; significances are marked by * if p < 0.05 and ** if p < 0.01)

LA LMA C Carea [cm2] [g m-2] [%] [mg m-2] Climber 18.3 (12.1) 93.5 (40.2) 44.1 (2.8) 41.7 (19.0) ** ** ** ** Tree 34.7 (40.1) 163.4 (76.9) 46.3 (3.3) 76.8 (39.7)

Appendix 7: Mean leaf element contents (Standard deviation in brackets; significances are marked by * if p < 0.05 and ** if p < 0.01)

Nmass Narea P K Ca Mg Mn Al [mg g-1] [mg m-2] [mg g-1] [mg g-1] [mg g-1] [mg g-1] [mg g-1] [mg g-1]

Climber 15.7 (4.9) 1376.7 (514.4) 0.8 (0.4) 17.52 (9.3) 6.3 (4.3) 3.6 (2.4) 0.7 (0.6) 0.1 (0.1) Appendices ** ** ** ** ** Tree 12.4 (4.5) 1843.7 (606.2) 0.5 (0.3) 12.6 (8.8) 7.0 (5.8) 3.0 (1.5) 0.6 (0.6) 1.3 (2.8)

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Appendix 8: Mean leaf structure parameters among all plots(Standard deviation in brackets; significances are marked by * if p < 0.05 and ** if p < 0.01)

LA LMA C Carea Plot GF [cm2] [g m-2] [%] [mg m-2] OF C 19.4 (18.2) 83.3 (30.7) 44.2 (1.2) 36.8 (11.1) *

T 38.4 (42.0) 111.8 (26.0) 46.3 (2.5) 51.8 (14.2)

DF C 22.7 (12.2) 56.2 (18.0) 41.3 (2.3) 23.3 (7.8) * ** ** T 64.0 (30.6) 102.1 (33.6) 43.2 (2.9) 44.6 (16.7) BF C 20.6 (15.4) 72.0 (24.4) 43.2 (3.0) 31.2 (10.7) ** * * T 34.7 (19.2) 133.8 (67.9) 46.9 (2.8) 63.3 (33.3) Appendices PF C 13.9 (6.5) 67.0 (19.5) 43.8 (1.9) 29.3 (8.4) * ** ** T 48.8 (42.7) 125.6 (19.2) 43.8 (2.8) 54.7 (7.2) KF C 12.2 (9.3) 123.2 (24.2) 47.5 (1.7) 58.4 (11.4) ** * T 11.4 (12.1) 188.2 (72.5) 48.5 (1.8) 90.8 (33.3) MF I C 19.1 (15.7) 87.2 (38.4) 42.1 (1.9) 36.4 (15.6) ** ** ** T 47.6 (75.0) 166.1 (53.9) 45.4 (2.1) 75.5 (25.0) MF II C 22.0 (5.6) 126.7 (31.4) 45.7 (2.3) 58.0 (14.7) ** ** T 21.0 (19.2) 229.9 (674.2) 47.7 (3.6) 111.5 (52.3) PA C 15.4 (6.8) 136.7 (42.5) 45.8 (1.4) 62.5 (19.4) ** * ** T 7.6 (12.1) 255.8 (49.2) 49.0 (3.0) 125.8 (26.4)

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Appendix 9: Mean leaf element contents among all plots (Standard deviation in brackets; significances are marked by * if p < 0.05 and ** if p < 0.01)

Nmass Narea P K Ca Mg Mn Al Plot GF [mg g-1] [mg m-2] [mg g-1] [mg g-1] [mg g-1] [mg g-1] [mg g-1] [mg g-1] OF C 18.8 (5.2) 1484.3 (330.9) 1.2 (0.4) 19.1 (6.1) 9.5 (6.1) 4.0 (1.9) 1.0 (0.9) 0.1 (0.2)

T 17.7 (6.5) 1918.1 (592.4) 1.1 (0.4) 18.5 (7.1) 7.2 (2.5)) 3.3 (1.4) 1.3 (0.6) 1.0 (2.9)

DF C 15.4 (4.9) 826.5 (7.8) 0.8 (0.3) 29.9 (14.3) 7.7 (3.1) 5.5 (1.8) 1.2 (0.7) 0.1 (0.1)

* * ** * T 13.1 (4.8) 1263.4 (378.2) 0.6 (0.3) 12.0 (4.3) 12.2 (10.2) 4.7 (1.7) 0.9 (0.9 2.4 (2.8)

BF C 13.8 (3.9) 959.9 (361.0) 0.6 (0.1) 20.3 (8.7) 5.8 (2.7) 4.9 (2.1) 0.5 (0.4) 0.1 (0.0) ** * T 12.1 (1.9) 1545.2 (586.9) 0.5 (0.2) 12.3 (7.1) 5.0 (3.3) 2.8 (1.6) 0.3 (0.3) 0.3 (0.7) PF C 14.9 (3.6) 960.5 (256.8) 0.6 (0.1) 15.9 (6.2) 4.5 (3.3) 2.6 (1.8) 0.7 (0.6) 0.1 (0.1)

** ** * Appendices T 12.6 (2.4) 1592.3 (448.5) 0.4 (0.2) 21.1 (18.3) 7.3 (5.7) 2.7 (1.6) 0.3 (0.3) 2.5 (5.4) KF C 13.5 (3.1) 1637.6 (401.4) 0.6 (0.2) 12.1 (1.9) 5.1 (3.6) 2.6 (1.2) 0.6 (0.6) 0.0 (0.0) * ** * T 12.4 (2.7) 2223.6 (552.9) 0.4 (0.1) 10.3 (6.0) 2.4 (1.6) 1.8 (0.8) 0.3 (0.2) 0.1 (0.1) MF I C 19.2 (6.4) 1472.6 (297.7) 0.8 (0.2) 14.2 (5.4) 6.1 (5.8) 3.3 (3.7) 0.6 (0.7) 0.1 (0.1) ** ** * T 11.6 (4.0) 1790.4 (349.5) 0.5 (0.3) 10.0 (3.5) 5.3 (3.3) 2.6 (1.0) 0.3 (0.3) 2.0 (2.9) MF II C 13.7 (4.8) 1619.6 (250.5) 0.7 (0.6) 14.4 (5.8) 3.5 (1.6) 3.4 (2.7) 0.5 (0.4) 0.0 (0.0) ** * T 11.1 (5.0) 2298.4 (674.2) 0.5 (0.2) 8.5 (3.7) 7.5 (5.3) 2.9 (1.1) 0.7 (0.6) 0.5 (0.8) PA C 16.7 (4.4) 2138.8 (350.8) 0.5 (0.2) 12.2 (4.1) 8.5 (4.3) 2.0 (1.5) 0.2 (0.1) 0.1 (0.0) ** ** * ** T 8.6 (1.1) 2189.2 (412.9) 0.2 (0.1) 8.3 (3.4) 8.2 (4.4) 3.1 (1.4) 0.9 (0.5) 1.2 (2.5)

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Erklärung

Hiermit erkläre ich, dass ich die vorliegende Arbeit selbständig verfasst und keine anderen als die angegebenen Quellen und Hilfsmittel verwendet habe.

Ferner erkläre ich, dass ich weder an der Universität Ulm noch anderweitig mit oder ohne Erfolg versucht habe eine Dissertation einzureichen, bzw. mich einer Doktorprüfung zu unterziehen.

(Jörg Salzer) Ulm, den 01. 10. 2003