Tropical bracken, a powerful invader of pastures in South Ecuador: Species composition, ecology, control measures, and pasture restoration DISSERTATION zur Erlangung des Doktorgrades der Fakultät Biologie, Chemie und Geowissenschaften der Universität Bayreuth vorgelegt von Kristin Roos aus Cottbus Bayreuth, im Juli 2010 Die vorliegende Arbeit wurde in der Zeit von September 2004 bis Juni 2010 unter der Leitung von Herrn em. Prof. Dr. Dr. h. c. Erwin Beck am Lehrstuhl für Pflanzenphysiologie angefertigt. Die Untersuchungen fanden im Rahmen der Forschergruppen „Funktionalität in einem tropischen Bergregenwald Südecuadors: Diversität, dynamische Prozesse und Nutzungspotenziale unter ökosystemaren Gesichtspunkten“ und „Biodiversität und nachhaltiges Management eines megadiversen Hochgebirgsökosystems in Südecuador“ statt und wurden durch Mittel der Deutschen Forschungsgemeinschaft gefördert (DFG FOR 402 und 816). Vollständiger Abdruck der von der Fakultät für Biologie, Chemie und Geowissenschaften der Universität Bayreuth genehmigten Dissertation zur Erlangung des akademischen Grades Doktor der Naturwissenschaften (Dr. rer. nat.). Promotionsgesuch eingereicht: 01. Juli 2010 Wissenschaftliches Kolloquium: 03. September 2010 Prüfungsausschuss: em. Prof. Dr. Dr. h. c. Erwin Beck (Erstgutachter) Prof. Dr. John Tenhunen (Zweitgutachter) Prof. Dr. Gerhard Gebauer (Vorsitzender) Prof. Dr. Thomas Nauß Prof. Dr. Gerhard Rambold Dedicated to my family Contents List of tables .......................................................................................................................................... II List of figures ....................................................................................................................................... IV SUMMARY ............................................................................................................................................. 1 ZUSAMMENFASSUNG .......................................................................................................................... 5 CHAPTER 1 Introduction Bracken: A cosmopolitan weed ................................................................................... 12 The study site in southern Ecuador............................................................................. 21 Objectives of the study ................................................................................................ 25 References .................................................................................................................. 26 CHAPTER 2 Synopsis Species composition of southern bracken in the research area .................................34 The use of fire for deforestation .................................................................................. 36 Bracken growth and its reaction to fire........................................................................ 37 Control of tropical bracken .......................................................................................... 42 Re-pasturisation with a common pasture grass ..........................................................44 References .................................................................................................................. 45 CHAPTER 3 Species composition and genetic diversity Roos K, Weig A & Beck E: Species composition and genetic diversity of tropical bracken invading pasture land in southern Ecuador. Molecular Ecology (submitted)................................................................................................................... 50 CHAPTER 4 Forest clearing by slash and burn Beck E, Hartig K & Roos K (2008) Forest clearing by slash and burn. In: Beck E, Kottke I, Makeschin F & Mosandl R (Eds.): Gradients in a Tropical Mountain Ecosystem of Ecuador. Ecological Studies 198, Springer Berlin Heidelberg, pp 371-374 ....................................................................................................................... 86 CHAPTER 5 The invasive capacity of bracken Roos K, Rollenbeck R, Peters T, Bendix J & Beck E: Growth of Tropical Bracken (Pteridium arachnoideum ): Response to weather variations and burning. Invasive Plant Science and Management (accepted) ...............................................................94 CHAPTER 6 Re-pasturisation of abandoned pastures in South Ecuador Roos K, Rödel HG & Beck E: Short-term and long-term effects of weed-control measures on bracken infested pastures and an attempt to regenerate abandoned pastures in South Ecuador. Weed research (submitted) .......................................... 121 Appendix further publications: Beck et al. (2008), Bendix et al. (2009). ........................................... 147 Record of contributions to this thesis ............................................................................................ 173 List of publications ........................................................................................................................... 175 Acknowledgements .......................................................................................................................... 176 I List of tables Tab. 1-1: Comparison of Pteridium arachnoideum and Pteridium caudatum (according to Tryon & Tryon, 1982; Alonso-Amelot & Rodulfo-Baechler, 1996; Thomson & Alonso- Amelot, 2002). The main differential character is given in bold.............................................14 Tab. 3-1: Experimental details of starch gel electrophoresis for allozyme analysis according to Müller-Starck et al. 2001 (modified as listed in the Table). ...............................58 Tab. 3-2: Characteristics of seven allozyme loci from Pteridium arachnoideum (a) and Pteridium caudatum (c). H O: observed heterozygosity; H Ec expected heterozygosity corrected for sample size .....................................................................................................68 Tab. 3-3: Characteristics of the five selected microsatellite loci from Pteridium arachnoideum (a) and Pteridium caudatum (c). H O: observed heterozygosity; H Ec expected heterozygosity corrected for sample size ..............................................................70 Tab. 3-S1: Plate layout and instrument settings for DNA purification via BindIT 3.1 KingFisher software. After step 7, eluted DNA was transferred to plastic cups and kept at -20°C....................................................................................................................................79 Tab. 3-S2: Morphological classification and allozyme banding pattern interpretation of 50 samples. The allozymes of each isozyme locus are numbered continuously beginning with the fastest (most anodal). a: P. arachnoideum , c: P. caudatum , ?: species classification was not possible..............................................................................................80 Tab. 3-S3: Results of the rps4-trnS sequencing (2 different sequences) and interpretation of microsatellite banding pattern. Occuring microsatellite alleles were numbered continously beginning with the smallest ...............................................................82 Tab. 3-S4: Allele occurence (and frequencies) of five microsatellite loci for P. arachnoideum ( a) with n = 30 and P. caudatum (c) with n = 19. Allele size “0” indicates null alleles. For one individual a present allele was only once counted indepently of zygosity or ploidy level..........................................................................................................84 Tab. 5-1: Correlations ( r values) between weather elements and frond dynamics for the 4-week periods. T = air temperature, rH = relative air humidity, Q = solar irradiance, R = Rainfall. For other acronyms refer to equations 1-3. Significant P-values are given in bold.. ..................................................................................................................................105 II Tab. 5-2: Influence of different variables on survival of rhizomes after heat pulse. Analyses were done with binary logistic regression with method of heat treatment and rhizome type as categorical variables, B gives the slope and W is the Wald value corresponding to P, significant P-values are given in bold..................................................112 III List of figures Fig. 1-1: Morphospecies of bracken in the San Francisco Valley, Ecuador A) Pteridium caudatum without free lobes, B) Pteridium arachnoideum with free lobes on the midrib between segments and pinnules (red arrows) ......................................................................15 Fig. 1-2: Schematic illustration of european bracken (Marrs & Watt, 2006; modified) and photograph of tropical bracken (K. Roos), (a) frond lamina, (b) stipe, (c) rhizome with (d) crozier. .................................................................................................................................16 Fig. 1-3: Schematic structure of the rhizome system of bracken (A) and detail from A, showing the frond producing short shoot (B) ........................................................................17 Fig. 1-4: Topography of the research site A) Ecuador (from Luizzo, 2008) and the location of the research area (from Beck et al. , 2008b), B) the research area in detail with the field station Estación Científica San Franscisco (ECSF) at 1,860 m a.s.l., C) aerial image with marked plot sites. White crosses: sampling sites of the population study (Chapter 3), red circles: observation