HABITAT UTILISATION OF FLAP-NECKED CHAMELEONS (CHAMAELEO DILEPIS) ON THE TELPERION NATURE RESERVE, MPUMALANGA PROVINCE, SOUTH AFRICA
by
TREVOR LOURENS O’DONOGHUE
submitted in accordance with the requirements for the degree of
MASTER OF SCIENCE
in the subject
NATURE CONSERVATION
at the
UNIVERSITY OF SOUTH AFRICA
SUPERVISOR: DR. K. SLATER
CO-SUPERVISOR: PROF. L.R. BROWN
JANUARY 2019
DECLARATION
Name: Trevor Lourens O’Donoghue
Student number: 46071296
Degree: MSc Nature Conservation
Habitat utilisation of Flap-Necked Chameleons (Chamaeleo dilepis) on the Telperion Nature Reserve, Mpumalanga province, South Africa
I declare that the above dissertation is my own work and that all the sources that I have used or quoted have been indicated and acknowledged by means of complete references.
______18 January 2019 SIGNATURE DATE
i DEDICATION
―And we know that all things work together for good to those who love God, to those who are the called according to his purpose.‖ Romans 8:28.
I dedicate this work to my Creator who gave me life and the talent to add and to contribute to the conservation ecology of the earth given to human beings to take care of and protect.
ii ABSTRACT
This study investigated habitat utilisation, seasonal distribution, dispersal and activity patterns and sexual dimorphism of the Flap-Necked Chameleon (Chamaeleo dilepis) on Telperion nature reserve. Telperion was delineated into four physiographic- physiognomic units based on vegetation and topography and sampled by following the Braun–Blanquet (Zurich–Montpellier) method. A modified TWINSPAN classification was performed to derive a first approximation of the major plant habitats whereby seven broad plant habitat units were identified potentially available to chameleons. Plant species richness and species diversity, plant densities and canopy cover were recorded and analysed in each of the seven habitat units.
Habitat units were surveyed for chameleons at night and included a wet and a dry season. For each chameleon observed the sex, age class and various morphological measurements were recorded. Morphology analysis of the data suggested female- biased sexual dimorphism in C. dilepis that may increase fecundity in C. dilepis. The General Additive Model was used in R and determined a statistical significance between recorded temperature, photoperiod, rainfalland the presence or absence of C. dilepis suggests that chameleons at Telperion have seasonal habits influenced by climatic variables and plant species richness and plant structure.
Females preferred to oviposit in grassland associated woodlands with sandy soils and high shrub canopy cover. Hatchlings would emerge from the nests and use the grassland associated habitats more than any other age class. Sub-adult and adult chameleons preferred more dense woodland with lower canopy cover and higher rockiness. This study contributes to chameleon ecology on grasslands and was the first study to be done on the ecology of C. dilepis in the grasslands of Telperion. The results will contribute to the conservation of open habitat species such as Chamaeleo dilepis especially in the grassland habitats of Mpumalanga.
Keywords: Ecology, ecosystem, species diversity, species richness grassland, canopy cover, TWINSPAN, sexual dimorphism, fecundity, oviposit, soft-shelled egg, conservation.
iii ACKNOWLEDGEMENTS
I would like to thank the Applied Behavioural Ecology and Ecosystem Research Unit (ABEERU) and the University of South Africa for the opportunity I was given to conduct this research and the use of the research facilities on Telperion Nature Reserve.
Telperion is a special place and I have enjoyed every moment of my research on this unique piece of conserved property so a big thank you to the Oppenheimer family, the Conservation manager of research and conservation at E Oppenheimer & Son, Dr Duncan Mac Fayden and Telperion Reserve manager Mrs Elasbé Bosch for considering my research at Telperion.
All surveys for chameleons were done during the night along with difficult terrain made walking transects difficult at most times. Carrying of research equipment, assisting with measurements and data collection carried on into the early mornings on most days. Not all of the data collection would have been possible if not for the many friends and colleagues who assisted me with the data collection. To Morné, Susannah, Alistair, Ishmael, Regan, Cassius and Rudi, I cannot express my gratitude enough for your help. If it was not for your assistance and company during the surveys this study would not have been possible and would have not met the deadlines.
To my supervisor Dr Slater and co-supervisor Professor Brown, thanks for always being available when I required assistance during my research, replying to my e- mails and for your assistance with the statistical analysis. Without your comments and advice during the writing of my chapters, I would certainly have written forever as my overthinking sometimes overshadowed my dissertation. Thanks for lifting my spirits in times when I felt the pressure.
To my parents Brian and Ingrid O’Donoghue who stood by my side all the way and who supported my career choice in conservation I cannot thank you enough.
Thank you to Michelle Merrick for your motivation and constant encouragement with your famous words ―Jy sal klaarmaak‖.
iv
TABLE OF CONTENTS
DECLARATION ...... i
DEDICATION ...... ii
ABSTRACT ...... iii
ACKNOWLEDGEMENTS ...... iv
LIST OF FIGURES ...... viii
LIST OF TABLES ...... x
ANNEXURE ...... xi
CHAPTER 1 – INTRODUCTION ...... 1
1.1 BACKGROUND TO THE STUDY ...... 1
1.2 STUDY SPECIES ...... 15
1.3 STUDY OBJECTIVES ...... 19
1.4 DISSERTATION OUTLINE ...... 20
1.5 REFERENCES ...... 20
CHAPTER 2 - STUDY AREA AND METHODS ...... 31
2.1 STUDY AREA ...... 31
2.1.1 History of the study area ...... 31
2.1.2 Landscape and topography ...... 32
2.1.3 Geology and Soils ...... 33
2.1.4 Vegetation ...... 34
2.1.4.1 Rand Highveld Grassland ...... 35
2.1.4.2 Loskop Mountain Bushveld ...... 36
2.1.5 Climate and rainfall ...... 36
2.1.6 Drainage...... 36
2.1.7 Alien Plants ...... 37
v 2.1.8 General animal species ...... 38
2.2 METHODS ...... 38
2.2.1 Vegetation ecology ...... 38
2.2.1.1 Vegetation data collection ...... 38
2.2.2.2 Vegetation data analysis ...... 41
2.2.2 Chameleon ecology ...... 42
2.2.2.1 Chameleon data collection ...... 42
2.2.2.2 Chameleon data analysis ...... 46
2.3 REFERENCES ...... 47
CHAPTER 3 – HABITAT CLASSIFICATION AND DESCRIPTION ...... 53
3.1 INTRODUCTION ...... 53
3.2 RESULTS ...... 55
3.2.1 Vegetation classification ...... 55
3.2.2 Habitat unit descriptions ...... 59
3.2.3 Density, Canopy volume and Height of woody vegetation ...... 68
3.2.4 Plant species richness and diversity ...... 69
3.2.5 Plant Species Similarity ...... 72
3.3 DISCUSSION ...... 74
3.3.1 Habitat types ...... 74
3.3.2 Species richness & diversity ...... 79
3.4 CONCLUSION ...... 81
3.5 REFERENCES ...... 84
CHAPTER 4 - CHAMELEON ECOLOGY ON TELPERION ...... 88
4.1 INTRODUCTION ...... 88
4.2 RESULTS ...... 89
4.2.1 Morphological measurements of C. dilepis ...... 89
4.2.2 Habitat utilisation ...... 93
vi 4.2.3 Seasonality ...... 96
4.2.4 Dispersal of C. dilepis ...... 98
4.2.5 Perch plant utilisation ...... 99
4.3 DISCUSSION AND CONCLUSION ...... 102
4.3.1 C. dilepis morphology and measurements ...... 102
4.3.2 C. dilepis habitat utilisation and dispersal...... 104
4.3.3 Seasonality of C. dilepis ...... 109
4.4 REFERENCES ...... 111
CHAPTER 5 – DISCUSSION ...... 116
5.1 INTRODUCTION ...... 116
5.2 DISCUSSION ...... 117
5.2.1 Morphology ...... 117
5.2.2 Habitat preference ...... 119
5.2.3 Seasonality ...... 133
5.3 ANECDOTAL DATA AND OBSERVATIONS ...... 136
5.4 CONCLUSION ...... 139
5.5 REFERENCES ...... 141
CHAPTER 6 – CONCLUSION AND RECOMMENDATIONS ...... 149
6.1 CONCLUSION ...... 149
6.2 MANAGEMENT RECOMMENDATIONS ...... 149
6.3 RECOMMENDATIONS FOR FURTHER STUDY ...... 150
6.4 SHORTFALLS AND LIMITATIONS TO THE STUDY ...... 150
ANNEXURE A ...... 151
List of plant species identified in the habitat units on Telperion during the study period ...... 151
vii LIST OF FIGURES
Chapter 1
Figure 1.1: Phylogenetic diagram that illustrates four major ancestral lines of lizards and the relationship of the lizard families (adapted from Mattison, 1992).
Figure 1.2: The common Flap-necked chameleon (Chamaeleo dilepis) has its common name derived from the skin flap that extends from the back of the head over the neck. Photo by T. L. O’Donoghue
Chapter 2
Figure 2.1: Location and boundary of Telperion in relation to the rest of South Africa.
Figure 2.2: The underlying geology of Telperion (Johnson & Wolmerans, 2008)
Figure 2.3: Main vegetation types of Telperion (SANBI, 2012).
Figure 2.4: Perennial watercourses and drainage lines on Telperion Nature Reserve (QGIS, 2009)
Figure 2.5: Morphological measurements made on C. dilepis for this study as adapted from Norval et al., (2014)
Figure 2.6: Tarsal spur on the hind foot and thickening in the tail caused by the hemipenes observed on a male C. dilepis at Telperion. Photo by T. L O’Donoghue
Chapter 3
Figure 3.1: Species richness, Menhinick’s Index and Margalef’s Index for the seven different habitat units on Telperion
viii Figure 3.2: Shannon-Wiener Entrophy and Rich-Gini-Simpson Index of the effective number of species values for the seven different habitat units on
Chapter 4
Figure 4.1: Mean perch heights of adult male and female C. dilepis during the study period on Telperion
Figure 4.2: The number of C. dilepis per age class in relation to temperature and rainfall on Telperion during the study period.
Figure 4.3: Monthly occurrences with numbers in the bars indicating the monthly observations of the various C. dilepis age classes found on Telperion during the study period
Figure 4.4: Dispersal of hatchlings from a nest site on Telperion recorded over a 14 day period
Chapter 5
Figure 5.1: A hatchling C. dilepis perching on Diheteropogon amplectens with Fadogia homblei undergrowth as a possible microhabitat. Photo by T. L. O’Donoghue
Figure: 5.2: A female C. dilepis excavating a nest site to oviposit during the study period. Photo by Ishmael Matomane
Figure 5.3: A female C. dilepis with mud on the body from nest excavation. Photo by T. L. O’Donoghue
Figure 5.4: A hatchling C. dilepis showing black colouration as an indication of stress during measuring and handling. Photo by T. L. O’Donoghue
ix LIST OF TABLES
Chapter 2
Table 2.1: Braun-Blanquet cover-abundance scale used in this study (Mueller- Dombois & Ellenberg, 1974)
Chapter 3
Table 3.1: Phytosociological table of the different habitat units studied at Telperion.
Table 3.2: The density, canopy volume and mean height classes of woody species per habitat unit (*no woody species recorded)
Table 3.3: The Jaccard Index values for species similarity between the seven habitat units at Telperion
Chapter 4
Table 4.1: Morphological analysis between the different age classes of male and female C. dilepis (*statistical significance at the 95% confidence level)
Table 4.2: Occurrence of C. dilepis in the seven different habitats compared to habitat availability within the study area
Table 4.3: The General Additive Model (GAM) Statistic for the association of climatic variables and the occurrence of various age classes of C. dilepis (*statically significant)
Table 4.4: Plant species that C. dilepis utilised as perches during the study period on Telperion
x ANNEXURE
Annexure A: The list of plant species identified in the vegetation surveys on Telperion
xi CHAPTER 1 – INTRODUCTION
1.1 BACKGROUND TO THE STUDY
Conservation of the world’s biodiversity has become an international responsibility. The vast range of species, biological processes of these species and the genetic variation within species have become important focal points in the last few decades (Primack, 2012). Biological communities that took millions of years to evolve are continuously being altered or destroyed as a result of human actions (Primack, 2012). It is expected that thousands of species and ecosystems will go extinct in the coming decades (Reid et al., 2005; Barnosky et al., 2011).
The ecosystems on which life and biological communities depend on are not standing still and nature changes every day (Reid et al., 2005). The earth and its ecosystems have a long and complicated history (Van As et al., 2012). For millennia, advanced forces of nature have transformed the earth but today human beings are the most powerful force of environmental change (Reid et al., 2005). Human forces that determine the outcomes of conservation attitudes and practices have largely evolved within the context of western societyand have been moulded by the major political, economicand intellectual revolutions of western society (Van As et al., 2012).
The interaction of a species with the physical and chemical resources within its surrounding environment is refered to as an ecosystem (Primack, 2012). Ecosystems are made up of many different living organisms that are in its entirety known as a community (Van As et al., 2012). Understanding how biological communities and ecosystems change within landscapes because of variations in physical conditions may assist with managing these communities. These physical changes may be the availability of water, the soil type, temperature, precipitation and human-influenced conditions. Within a biological community, each species has its’ own requirements for resources. Habitats for shelter and water resources are examples and if any is removed or added, it may limit the population size and the distribution of such a species (Primack, 2012). Changes in the habitat situations by
1 way of climate, predators or human influences may influence resource preferences of a species that could cause a species population to decline or go locally extinct from an ecosystem (Sinclair et al., 2006).
Conservation biology is the integrated scientific field developed to gain knowledge with the challenge of conserving species and ecosystems (Primack, 2012). With the development of practical approaches to prevent, the extinction of species and how the major unknowns are approached can only be determined by the search for facts and knowledge gained through much needed scientific research (Barnosky et al., 2011; Primack, 2012). For many species, the knowledge available and pertaining to the ecological key facts/influences is not sufficient to ensure their conservation and survival (Primack, 2012). This effectively means in areas where species are at risk, management decisions may affect species detrimentally (Sincair et al., 2006). Management plans that are conservation goal orientated are required but must be practical in the methods they include for achieving these goals (Primack, 2012). Several types of information regarding a species are important to obtain through applied behavioural ecological research. The information can be obtained through research in the field and will for the benefit of the species studied, include environmental and habitat requirements, distribution and biotic interactions, morphology and physiology (Primack, 2012). Conservation has also developed from an exclusive concern with the protection of animals to the protection of entire ecosystems in which all living organisms have a legitimate role to play (Marais et al., 2009). The development of scientifically sound management plans for conservation areas (Marais et al., 2009) can only be achieved with the availability of scientifically sound information on the various biotic and abiotic components and interactions of ecosystems.
Habitat loss and degradation, the unsustainable trade of wildlife, invasive species and pollution have resulted in the decline of many species including reptiles across the world (Gibbon et al., 2000, Cox & Temple, 2009; Todd et al., 2010). Reptiles have a narrower distribution than other vertebrates such as birds and mammals and they are susceptible to anthropogenic threats (Adalsteinsson et al., 2009; Oliver et al., 2009; Nagy et al., 2012). Reptiles play significant roles in ecosystems, as predators and/or prey as well as being bio-indicators for the environmental health of
2 their often specific microhabitat associations (Read, 1998; Raxworthy et al., 2008). Assessments of reptile species in southern Africa (Bates et al., 2014) indicate that one-fifth of South African and one-tenth of Lesotho and Swaziland’s reptilian species respectively are threatened with extinction.
Ancestral reptiles and amphibians dominated the earth during the Carboniferous period, 300-350 million years agoand continued to diversify and specialise to fill a variety of niches (Mattison, 1992). Based on fossil records of modern reptiles, amphibians and their direct ancestors, these species have had a long and complex evolutionary history since their first appearance on earth (Hedges & Poling, 1999) 230 million years ago (Mattison, 1992). The class Reptilia (reptiles) is grouped into four different orders namely: Squamata (lizards, snakes and amphisbaenas) (Figure 1.1), Chelonia (tortoises, terrapins and turtles), Crocodilia (crocodiles and alligators) and Sphenodontids (tuataras) (Mattison, 1992; Le Berre, 2009). Within these groups, 9084 species of reptiles have been described so far (Uetz, 2010). Squamata is one of the largest reptile groups (Tolley & Burger, 2007) that first appeared about 180 million years ago during the Triassic period (Mattison, 1992) and contains about 6000 species of which almost half are made up of lizards (sub-order Sauria), 130 Amphisbaenians and the remaining species are snakes (Mattison, 1992).
3 Gekkonidae Gecko line Pygopodidae
Iguanidae
Iguana line Agamidae
Chamaeleontidae
Lacetidae Lacertid line Teiidae
Lizards Skink line Xantusiidae Scincidae
Cordylidae
Dibamidae
Anguidae Squamata Anniellidae Anguid line Xenosauridae
Varanidae Amphisbaenidae Varanid line Helodermatidae Trogonophidae Amphisbaenians Lanthonotidae Rhineuridae
Bipedidea Serpentes
Figure 1.1: Phylogenetic diagram that illustrates four major ancestral lines of lizards and the relationship of the lizard families (adapted from Mattison, 1992).
Apart from the polar regions of the earth (Pough et al., 2004), reptiles can be found all over the world (Pincheira-Donoso et al., 2013) and lizards usually make up the most noticeable of the reptile fauna (Mattison, 1992). Lizards differ from other Squamata, by having four legs and moveable eyelids thus making lizards similar to crocodilians and tuataras. However, the fundamental difference in the skull structures between crocodiles and lizards is that crocodiles lack bony eye rings and bony palate plates and scales that do not overlap as they do in lizards (Mattison, 1992). Tuataras are nocturnal and lack ear openings in the skull (Mattison, 1992).
Lizards were able to colonise the land by developing internal fertilization and, unlike amphibians, lizards produce eggs that contain all the necessary nutrients to nourish the embryo (Mattison, 1992). The eggs can either remain and develop in the
4 reproductive tract where the female gives birth to live young (viviparous) or the female can deposit shelled eggs (oviparous) that develop and hatch in the external environment (Blackburn, 1999). Lizards became the first animals with eggs developed to contain a large yolk termed a telolecithal, amniotic egg and lizards may be oviparous or viviparous (Mattison, 1992). There are advantages and disadvantageous to viviparous and oviparous breeding behaviour (Blackburn, 1999). Viviparous egg development is higher in areas with high altitudes and latitudes. It protects the embryo from extreme external temperatures, fungal attacks and predation but it may inhibit a female’s mobility and reduces her ability to feed (Blackburn, 1992). Oviparous egg development exposes eggs to higher predation and microbial attacks and dehydration, whereas the advantages are higher mobility and development of the next batch of eggs can start soon after they have been deposited (Blackburn, 1992). Lizards that produce external eggs mostly have a soft shell that is permeable to allow for gasses and water to be exchanged (Mattison, 1992). Geckos and pygopods lay hard-shelled eggs (Mattison, 1992).
Seasonal variations such as rainfall or dry periods may act directly on other requirements such as food supply and it may affect the breeding behaviour as most lizards breed at times of the year that will ensure that the young hatch or are born during the most favourable times for the best chance of surviving (Mattison, 1992). There is no maternal care after the eggs are laid and after hatching, neonates are completely dependent on themselves for survival (Mattison, 1992). Within habitats located in cold climates, the breeding seasons are shorter and females may only lay one clutch of eggs a year whilst in warmer climates female lizards may lay multiple clutches of eggs (Mattison, 1992).
Little is known about the survival needs of lizards and genrally much is still to be researched in terms of threats and lizard habitats (Mattison, 1992).
Lizards regulate their body heat by relying on outside heat sources such as sunlight to warm up (Mattison, 1992). The reliance on external thermal regimes results in lizards making use of different habitats with different traits based on topography, underlying geology and the changes in climate and lizards have adapted to live in the different habitats (Mattison, 1992). For example, rocky areas and rocky outcrops
5 are considered good habitat for lizards and lizard species richness is higher in these areas as it provides good shelter from heat, cold and predators and is generally rich in food sources such as insects (Mattison, 1992). Grassland and savanna habitats can also be rich in lizard species but these species are vulnerable to predation and therefore tend to be faster and have longer hind legs to escape predation (Mattison, 1992). Lizards may not only use speed for fleeing but can use other forms of defence such as mimicry, crypsis, active defence and camouflage to avoid being eaten by predators (Mattison, 1992). Males of various lizard species will change their colour during the breeding season (Mattison, 1992) and other lizards will change their colour faster to indicate their mood or for the purpose of heating and cooling or anti- predator behaviour and state of health (Matisson, 1992; Tolley & Burger, 2007; Le Berre, 2009).
Adaptations by lizards to inhabit habitats that experience seasonal dry periods during the year include morphological adaptations such as scales and thick skins that are impermeable to water (Mattison, 1992). In general reptiles have the ability to discard of their waste nitrogen in the form of white uric acid crystals and require little water to transport it out of the body (Bradshaw, 1988) and they may be able to obtain their water from the food that they eat and never need to drink water (Mattison, 1992). During unfavourable times of the year, lizards may become dormant and remain dormant until environmental conditions are suitable again to become active (Sanders, 2008).
Various shapes and sizes of lizards exist due to morphological adaptations toward their environment and evolutionary history (Mattison, 1992; Meyers & Clarke, 1998). Examples of this are that some of them are small, delicate and secretive compared to species that are large and decorated with crests, horns, flaps and frills. One such a group of lizards that can be easily identified are the chameleons. Characterised by morphological and physiological adaptations chameleons are highly specialized animals (Tolley & Herrel, 2014).
Chameleons are lizards that fall within the family Chamaeleonidae (Tolley & Herrel, 2014). Fossil records suggest that lizard families such as Chamaeleonidae, Iguanidae (iguanas) and Agamidae (Agamas) evolved from a common ancestor
6 about 100-120 million years ago and when compared to most of the other Squamates the family Chamaeleonidae is a fairly young clade (Tolley & Burger, 2007, Townsend et al., 2011).
Just as lizards, in general, create interest amongst people with their bright colours and fast movements (Mattison, 1992), chameleons also attract a lot of attention by nature lovers and around the world and they awake mystery and fear with their unusual characteristics such as rapid colour changes, independently moving eyes and their projectile tongue (Tolley & Burger, 2007). Chameleons are slow moving with the ability to change colour for emotional display, camouflage and thermoregulation (Wager, 1983; Brain, 1961; Tolley & Burger, 2007; Le Berre, 2009). The laterally compressed body with its prehensile feet and tail and long projectable tongue are characteristics that distinguish chameleons from other lizards (Gans, 1967; Tolley & Herrel, 2014).
The sensory system of the chameleons is strongly developed toward visual stimuli in their social and feeding behaviour and chameleons have adapted into highly specialised visual arboreal predators (Gans, 1967; Tolley & Herrel, 2014). Their arboreal behaviour has facilitated the development of adaptations and the prehensile feet and tail that have resulted in the chameleon to be one of the slowest moving of all the lizard species (Tolley & Burger, 2007). The feet are used for gripping and the occurrence of the prehensile tail in chameleons is effectively a fifth limb (Tolley & Burger, 2007) used for clinging onto branches (Mattison, 1992, Herrel et al., 2013). In a study by Hopkins and Tolley (2011) they compared the tail lengths of Bradypodion pumilum (Cape Dwarf Chameleon) in forest habitats compared to open habitat such as fynbos. They found that B. pumilum forest habitats had a longer tail length than B. pumilum occupying more open habitat (Hopkins & Tolley, 2011). Some chameleon species such as Chamaeleo namaquensis (Namaqua Chameleon) live predominantly on the ground in desert habitats without trees (Burrage, 1972). C. namaquensis has a tail that is not as prehensile as in other chameleon species but it can still be used when climbing (Mattison, 1992). In the ground-living genus such as Brookesia species (Malagasy Dwarf Chameleon) the tail is shorter than in other species (Boistel et al., 2010). The shorter tail is used to balance the chameleon by making contact with the substrate that it moves on, indicating that even ground-living
7 chameleons use their tails for enhancing stability albeit in a different way than clinging (Tolley & Herrel, 2014).
The ecology of chameleons has been poorly studied probably because of their cryptic nature and it is believed that assemblages are divided according to open habitat (savanna, grassland, heathland and woodlands) and closed habitat (forests) (Tolley & Herrel, 2014). The genus Chamaeleo is related to open habitat whereas forest dwelling genera include Brookesia, Kinyongia, Rhampholeon and Calumma. Another group prefers both open and closed habitats and they are Bradypodion, Trioceros, Furcifer and Rippeleon.
The majority of chameleons are insectivorous, but larger species such as Furcifer and Calumma are able to feed on smaller lizards, birds and small mammals (Tolley & Burger, 2007) and in captivity chameleons will feed on smaller chameleons if conditions are crowded (Mattison, 1992). In environments that are more arid and in captivity, chameleons have been known to eat plant material as compensation to promote moisture intake (Le Berre, 2009). Chameleons are efficient in catching their food by stalking and catching prey items with their long extendable tongue (Mattison, 1992; Tolley & Burger, 2007) The ballistic tongue projection of chameleons in arboreal habitats may have evolved to minimise the physical chasing and grabbing of prey (Schwenk, 2000). The tongue can be extended as long as or longer than the body length of the chameleon (Tolley & Burger, 2007). In most lizards the method of searching for and catching food is largely dependent on the type of prey or food that they consume. Insect-eating lizards will sit and wait for prey to pass by or will actively search for it, as is the case with the majority of insect-eating lizards where they move fast and catch their prey using speed (Mattison, 1992). Chameleons lack speed and move around slowly searching for unsuspecting prey (Tolley & Herrel, 2014). When focussed on a prey item the chameleon will reduce the distance between itself and the prey (Bell, 1990; Schwenk, 2000). It then projects its tongue forward out of its mouth (Bell, 1990; Wainwright et al., 1991; Wainwright & Bennet, 1992; Schwenk, 2000) with the assistance of specialised bones and muscles that is referred to as elastic recoil (De Groot & Van Leeuwen, 2004). The tip of the tongue is thicker and surrounds the prey item like a suction cup (Herrel et al., 2000) and soon afterwards the chameleon withdraws the tongue back into the mouth, using muscle contractions
8 (De Groot & Van Leeuwen, 2004) bringing along with the tongue the prey caught. Once the tongue surrounds prey it is rarely lost making this specialised technique used by the chameleon a largely successful adaptation (Tolley & Burger, 2007). Chameleons do not have molars or incisor teeth, instead, they have a serrated jaw that crushes prey before it is swallowed whole (Tolley & Burger, 2007).
The broad range of habitats that chameleons inhabit can increase its body temperature up to 38oC in deserts (Burrage, 1972) and other species of chameleon will have to deal with temperatures of below freezing in alpine habitats (Reilly, 1982). In these alpine habitats, it has been documented that some chameleons can feed at temperatures as low as 3.5oC (Burrage, 1972). The temperature may have strong effects on the muscular function and on an organism's performance as a whole (Tolley & Herrel, 2014), especially the muscle contraction rates and locomotive capabilities of an organism (Huey & Stevenson, 1979; Bennet, 1985; Rome, 1990; Herrel et al., 2007). The use of the elastic recoil to shoot the chameleon's tongue forward is not affected by temperature (Rigby et al.,1959) because at this stage the tongue has pre-loaded tension. Because of the pre-loaded tension of the tongue, the loading before projection occurs at a slower rate but the actual projection rate is the same as it is at warmer temperatures (Anderson & Deban, 2010). Tongue retraction however after prey has been captured may be strongly affected by temperature as it relies on muscle contraction (Anderson & Deban, 2010). Even in lower temperatures, the tongue still holds onto prey efficiently during prey retraction (Herrel et al., 2000). Although retraction may be slower at lower temperatures, the muscle tension that has to attract the tongue (Bennet, 1985; Rome, 1990; Lutz & Rome, 1997; Anderson & Deban, 2012) lowers the risk of a chameleon losing its prey when prey is captured. This also suggests that chameleons will be able to capture prey and feed at lower temperatures and at a wider temperature range than other lizards thus allowing chameleons a wide-ranging thermal niche in which it can feed within (Anderson & Deban, 2010). Early morning feeding by chameleons is then possible before thermoregulation can increase the chameleon's body temperature (Reilly, 1982) while other lizard species are still inactive during this time of the day (Hebrard et al., 1982).
9 Chameleon densities vary between species, amongst habitats and with seasons (Brady & Griffiths, 1999), especially where seasonal influences on the availability of food, suitable habitat and environmental variances such as precipitation and temperature are high. None of these factors has been studied using sufficient time scales (Tolley & Herrel, 2014). Chameleons survive less favourable seasons by displaying dormant behaviour and seeking out dry suitable areas where they aestivate (Tolley & Herrel, 2014). Another possible strategy by chameleons to escape unfavourable conditions is to migrate to more suitable habitats such as riparian zones (Brady & Griffiths, 1999; Rabearivony et al., 2007).
Most chameleons roost alone and roosting sites are selected to avoid nocturnal predation related to hand foot size relationships with the perch diameter (Herrel, et al., 2011). In arboreal species, the tip of the smallest possible branch or leaf is selected to only support the weight of the chameleon and not any additional weight such as that of a potential predator. When a predator does approach, it will alert the chameleon of its presence through vibrations that will give the chameleon advanced warning of its approach (Tolley & Herrel, 2014).
Chameleons have a range of predators from birds, amphibians, snakes, spiders, tree-climbing mammals and even larger insects (Tolley & Burger, 2007; Tolley & Herrel, 2014). In captivity larger chameleons that have been known to cannibalise on newly hatched young if not separated (Le Berre, 2009) and in the wild habitat partitioning at different perch heights between adults and juvenile Chamaeleo chamaeleon have been observed to avoid cannibalism between conspecifics of different ages (Keren-Rotem et al., 2006; Esty, 2006). Chameleons mainly use camouflage or simply hide to avoid been seen by predators, this tactic is known as crypsis (Mattison, 1992; Tolley & Herrel, 2014). Because chameleons cannot use speed to evade predators they will resort to active defence by hissing and inflating themselves to look larger showing the orange inside of the mouth at times (Wager, 1983, Branch & Van Rooyen, 1991; Cuadrado et al., 2001). Younger chameleons such as hatchlings of Chamaeleo dilepis have been noticed to let go of their perch and drop to the ground and in some cases feign death if threatened (Brain, 1961).
10 The Chameleons ability to change colour (Wager, 1983; Mattison, 1992; Tolley & Burger, 2007) for the purpose of displaying emotion, thermoregulation and breeding behaviour is faster than recorded in most other lizards (Mattison, 1992). The change in colour of chameleons is caused by cells in the in the skin called chromatophores (Le Berre, 2009; Tolley & Herrel, 2014). The colour changing cells are contained in the dermis of an ectotherm and these cells are responsible for generating skin and eye colour (Bagnara & Hadley, 1973; Fox, 1976). Colour changes occur when pigment-containing organelles within chromatophores move by contracting and expanding (Tolley & Herrel, 2014).
Chameleons are polygamous and territorial behaviour during mating varies between species and genera (Tolley & Herrel, 2014). Males mate with more than one female and females will mate with more than one male (Wager, 1983) or mating will occur with the same male repeatedly during a mating season or ovarian cycle (Tilbury, 2010). Mate guarding varies amongst species even within the same genus. Males of Chamaeleo chamaeleon may guard a female during mating with extended guarding periods of up to 40 days (Cuadrado, 2001). Cuadrado (2001) observed male C. chameleon defending home ranges that did not overlap other males’ home ranges but it incorporated home ranges of one or more females. In species, such as Chamaeleo dilepis a solitary chameleon that only tolerates another conspecific during mating (Brian, 1961; Toxopeus et al., 1988). There is no indication that Chamaeleo dilepis have a stable home range moving considerable distances in search of a mate and vigorously repel any conspecifics it encounters has been observed (Brian, 1961).
Male chameleons will court females with a lateral body compression display, legs rigidly beneath the body and head shaking with the tail coiled even if they are not– receptive (Mattison, 1992; Cuadrado & Loman, 1999; Kelso & Verrel, 2002; Stuart- Fox & Whiting, 2005; Tolley & Burger, 2007). When the female is ready to mate the male will approach the female from behind (Tolley & Burger, 2007) and twist his tail so that it is underneath the female where he upturns one of the hemipenes to transfer sperm directly into the cloaca of the female (Mattison, 1992; Tolley & Burger, 2007). After mating, the female initiates disengagement by moving (Tilburry, 2010).
11 Chameleon females can store sperm from males for long periods (weeks, to months or across female ovarian cycles) and multiple broods have been recorded without the occurrence of mating (Tilburry, 2010). Sperm storage in chameleons is a development that may ensure fertilization when encounters with male chameleons are low and it may allow females to progress from one ovarian cycle to the next without going through the high cost of mating again (Tolley & Herrel, 2014).
During mating and mate encounters chameleon’s coloration changes between gravid, receptive and non-receptive females (Tolley & Herrel, 2014). Female Chamaeleo dilepis have yellow spots when gravid (Brian, 1961) and Chamaeleo chamaeleon females will have yellow spotting when sexually receptive with a darker coloured body and bluish and yellow spots with aggressive rejection toward males after mating (Cuadrado, 1998a). Fighting between male lizards may occur if another male is in the vicinity of a receptive female (Mattison, 1992). In chameleons, the intensity of male aggression is likely to differ from one species to another and aggression of males toward each other will be more intense during the breeding season (Singh et al., 1983).
Sexual dimorphism occurs in most chameleon species with some males having secondary characteristics such as horns or cranial and vertebrate crests are better developed (Le Berre, 2009, Tolley & Herrel, 2014). The difference in body size between males and females vary from larger males to larger females (Tolley & Herrel, 2014) and is similar to many other lizard families (Fitch, 1981). It has been documented by Nečas and Porras (2004) that female-biased sexual dimorphism in chameleon genera occurs in Rhampholion and Brookesia and larger males are found in species such as Chamaeleo and Culumma. Larger body size in males does not necessarily have a higher advantage in terms of success during courtship, for example in species such as Chamaeleo chamaeleon a larger body had advantages with courtship effort promoting reproductive success (Cuadrado, 2001). Where female chameleons have a larger body size it is likely to increase fecundity of the species and promote higher offspring production (Burrage, 1972; Lin & Nelson, 1980; Cuadrado, 1998b).
12 Depending on the species, chameleons can be oviparous and viviparous (Tolley & Herrel, 2014). Egg laying chameleons bury their eggs in the ground (Le Berre, 2009) and will search for suitable ground conditions in which to dig nests (Brian, 1961). Other egg laying chameleons such as Brookesia stumpfii place their eggs in depressions under dead leaves at the bottom of the forest floor (Raxworthy, 1991). Oviparous chameleon eggs have a leathery soft outer shell (Wager, 1983) that is porous to allow for moisture and gaseous exchange to occur to prevent the embryo from dying (Rimkus, 1996). Chameleon eggs have a developmental arrest called embryonic diapause that is not documented in any other Squamata (Andrews & Karsten, 2010). When eggs are laid and embryonic diapause occurs the eggs of chameleons are in gastrulaeand gastrulation occurs, so slowly that egg development can be paused for several months (Andrews & Donoghue, 2004; Ferguson et al., 2004). Embryos of Chamaeleo chamaeleon that lay their eggs close to the winter, will enter cold torpor causing the second suspension of development that results in synchronous hatching of the eggs over a number of days, even if the eggs were deposited by females at different times (Andrews et al., 2008). High temperature during diapause (summer) will delay developmental resting, however a period with lower temperatures (such as winter) followed directly by an increase in temperature (spring) will end the diapause and speed up embryo development (Ferguson et al., 2004; Andrews et al., 2008). The embryonic diapause of eggs is well developed in chameleons that occur in highly seasonal and arid environments so that embryo development is inhibited during the colder winter months (Brady & Griffiths, 1999).
As soon as the eggs hatch and the young emerge from the nest site they will disperse into the surrounding vegetation (Brian, 1961; Wager, 1983). Viviparous chameleons such as Bradypodion species develop its young within separate sacs inside the female’s body until she deposits the sacs on the surrounding vegetation and the neonates then break free and may stay close to the female for a couple of days before dispersing (Tolley & burger, 2007). Chameleons do not show any parental care and the hatchlings or newly born young are on their own (Tolley & Burger, 2007).
The maturity of chameleons varies from six months in Bradypodion species to a year in Chamaeleo species (Wager, 1983; Tolley & Burger, 2007). In Furcifer labordi the
13 entire life cycle of the chameleon is completed in five months that comprises of juvenile growth, maturation, courtship and death, leaving only eggs to hatch in the following year (Karsten et al., 2008). Longevity of chameleon species overall is poorly documented in the wild with most observations made from specimens bred in captivity (Le Berre, 2009; Tolley & Herrel, 2014).
The distribution of chameleons is mostly restricted to Madagascar, Africa, the Arabian Peninsula, southern fringes of Europe and India (Tolley & Burger, 2007). There has also been introduced species into North America (Ferguson et al., 2004). In these global distributions chameleons are found in a variety of habitats that differ in thermal and climatic conditions so that chameleon species have adapted to dry hot deserts, tropical rainforests, high altitude mountainous environments and Mediterranean climates (Tolley & Herrel, 2014) and habitats ranging from forests, fynbos, grasslands, savannas, coastlines and high mountain ranges (Tolley & Burger, 2007). The distribution of chameleons is attributed to various factors such as food, water, vegetation and solar radiation for body heat. Different habitats exist within larger plant communities and their characteristics are determined mostly by climate, soils, topography, fire, water availability and frost (Tainton, 1999; Van As et al., 2012).
At least 196 chameleon species have been described within 11 genera. Seven chameleon genera occur in Africa and 21 species from three of these genera are found in southern Africa: Bradypodion -17 species, Rhampolion -2 species and Chamaeleo -2 species (Tolley & Herrel, 2014). Twenty of the 21 southern African species are endemic to southern Africa, whilst South Africa is the third most chameleon rich country in the world (Le Berre, 2009). The genus Bradypodion (consisting of 17 species) is endemic to South Africa (Tolley & Burger, 2007; Tolley & Herrel, 2014).
Chamaeleo is the most widespread chameleon genus globally and the only genus found on more than one continent within many different habitats within various vegetation types (Tolley & Burger, 2007). With adaptations to survive in the aridest habitats and vegetation biomes including deserts, some southern African endemics such as Chamaeleo namaquensis occurs in areas within the Namibian desert that
14 receives rainfall of 14 mm per annum. The only non-endemic species within the Chamaeleo genus to southern Africa is Chamaeleo dilepis and has been found to be the most widely distributed of the other southern African species (Tolley & Herrel, 2014).
1.2 STUDY SPECIES
The Common Flap–Necked chameleon (Chamaeleo dilepis) was first described by William Leach (1819). It is one of the larger chameleons in southern Africa and C dilepis can reach snout to tail lengths of 25 to 35 cm (Wager, 1983; Tolley & Burger, 2007; Le Berre, 2009). C. dilepis occupies a range of vegetation types and habitats across most of tropical Africa (Tolley & Burger, 2007). C. dilepis is a typical open habitat or non–forest chameleon that often moves on the ground from one patch of wooded vegetation to the other (Wager, 1983; Tolley & Herrel, 2014) and has been regarded as a terrestrial species (Losos et al., 1993; Bickel & Losos, 2002) and usually moves on the ground to lay its eggs (Herrel, et al., 2013). Chameleons in open habitats have increased exposure to predation (Herrel et al., 2013) and these habitats are exposed to higher rates of sunlight resulting in lower humidity that increases the drought potential of these habitats. Therefore, chameleons in open canopy habitats evolved adaptations to deal with water stress, behavioural and morphological adaptations (Tolley & Herrel, 2014) such as smaller body sizes and less ornamentation as found in typical forest-dwelling species (Measey et al., 2009). The open habitats are also more vulnerable to fire that can largely reduce chameleon populations, or can change the landscape for the individuals that survive (Tolley & Herrel, 2014). All chameleons are bound by the vegetation type that they are found inand due to the extension of open habitat in Africa currently the open habitat chameleons are wide-ranging (Tolley & Herrel, 2014). Savanna now covers a large part of Africa and as a result, chameleons living in savanna have the widest distribution of any other species.
The body colouration of C. dilepis varies from bright lime green to brown and may exhibit dark barring or spotting when disturbed or stressed and the flanks have distinct white markings (Tolley & Burger 2007). C. dilepis is easily identified in the
15 field due to the presence of a skin flap that extends from the back of the head over the neck (Figure 1.2) (Meyers & Clarke, 1998; Tolley & Burger 2007).
The neck flap where C. dilepis’ common name is derived from
© T O’Donoghue, 2013/06/02 Figure 1.2: The common Flap-necked chameleon (Chamaeleo dilepis) indicating the characteristic skin flap at the back of the head. Photo by T. L. O’Donoghue.
Like most chameleons, C. dilepis is mostly active during the daytime and will perch on branches during the night to sleep (Brian, 1961, Wager, 1983; Tolley & Burger, 2007; Le Berre, 2009, Tolley & Herrel, 2014). A female C. dilepis has however been observed looking for suitable nest sites to lay eggs at night (Brian (1961). When not mating C. dilepis are usually found alone (Toxopeus et al., 1988). C. dilepis will display aggression toward any conspecifics by hissing and displaying dark colours or resorting to a physical confrontation (Brian, 1961; Wager, 1983; Tolley & Burger, 2007).
Mating takes place from early spring to during summer and the female oviposit’s her eggs (± 20 to 60 at a time) (Reaney et al., 2012) in the ground by digging a hole with her front legs and sometimes using the forehead to assist (Wager, 1983, Tolley & Burger, 2007). In the Leeupoort Nature Reserve located within the South African
16 Central Bushveld regions of the Limpopo Province, females were noted to be gravid during late summer in February and hatchlings were observed between the months of December to February which correlated with the highest rainfall recorded during these months. (O’Donoghue, 2014) hatching of the eggs can take between 5 to 12 months (Wager, 1983; Branch & Van Rooyen, 1991; Tolley & Burger 2007). C. dilepis eggs have embryonic diapause, because the eggs spend cold winters underground and will hatch after the first rain (Le Berre, 2009; Andrews & Karsten, 2010; Reaney et al., 2012). When juveniles emerge from the nest, they are about 3 to 6 cm in length (Brian, 1961; O’Donoghue, 2014). The young will remain around the nest for about a day (O’Donoghue, 2014) before dispersing (Le Berre, 2009). C. dilepis may reach sexual maturity in 9 to 12 months of age (Wager, 1983; Tolley & Burger, 2007; Le Berre, 2009).
The vegetation biomes such as savanna and grassland that C. dilepis are known to inhabit are vulnerable to fire which could influence chameleon populations within these biomes and may cause C. dilepis to move to alternative areas as an escape in order to find food and vegetation for cover (Tolley & Herrel, 2014). C. dilepis may disappear during the winter in dry, cold or high-elevated areas, when they may become dormant, but observations of C. dilepis perching on the same branch for prolonged periods have also been recorded during winter in the Pretoria region of South Africa (Wager, 1983). Dormancy may also occur in extremely dry seasons or prolonged periods without any rainfall (Wager, 1983).
Chameleons are one of the most understudied groups of lizards (Tolley & Herrel, 2014). Due to their cryptic nature during daytime chameleons are difficult to study during the day (Tolley & Burger, 2007; Tolley & Herrel, 2014). Due to the lack of studies on these animals, there is very little understanding of the general ecology of most chameleon species (Tolley & Herrel, 2014).
Studies on South African chameleons have mostly been conducted on the Dwarf chameleons (Bradypodion species). Some of these recent studies published on Bradypodion species focused on sexual dimorphism (Da Silva et al., 2014a, Da Silva & Tolley, 2013), locomotive performance in micro-habitat structure (Da Silva et al., 2014b), functional consequences of morphological differentiation (Herrel et al.,
17 2011), analysis of gripping and running performances (Herrel et al., 2013), survival and abundance of Bradypodion pumilum inhabiting a transformed semi-urban wetland (Katz et al., 2013), survival and movement of Bradypodion pumilum within a fragmented urban habitat (Tolley et al., 2010) and paternity sperm storage in Bradypodion pumilum (Tolley et al., 2014).
C. dilepis is regarded as a widespread and common, species (Wager, 1983; Tolley & Burger, 2007; Tolley & Herrel, 2014). However, most African mainland chameleon species is an overlooked group of lizards (Tolley & Herrel, 2014). The most recent studies published for C. dilepis is based on the ecology conducted on museum specimens (Reaney et al., 2012) and the cryptic genetic diversity of C. dilepis that focused on the genetic heredities and differences between the geographical distribution of the species (Main et al., 2018). Herbrard and Madsen (1984) in Kenya investigated habitat partitioning of male and female C. dilepis during wet and dry seasons. No other published studies investigating habitat utilisation, dispersal and seasonal activities of C. dilepis have recently been published.
This study of C. dilepis is the first to contribute to the understanding of the ecology of this cryptic lizard within the Mpumalanga grasslands of South Africa. Due to the variety of habitats and plant communities C. dilepis occurs within, the lack of ecological understanding of this species in terms of habitat preferences within larger plant communities, seasonality, dormancy, dispersal and the important ecological roles that C. dilepis forfill within natural ecosystems creates a significant need for more research into the ecology of this species.
The outcomes of this research will contribute to the knowledge of C. dilepis within the grassland biome and Mpumalanga province, especially when the management of their preferred habitats, movement within habitats and their seasonal activities are considered. Research outcomes implemented in a reserve management plan should contribute to a starting point for the adaptation of the reserve management plan to lessen the impacts that any of the management activities have on chameleon populations.
18 With sufficient information on the biological and environmental habits and habitat requirements of chameleon species, the threats to current populations and the effects that these threats may have can be addressed. This information will be a requirement in order to conserve chameleon populations over the next 20 years (Tolley & Herrel, 2014). Currently, most nature conservation authorities and reserves have no formal management plans for reptiles and as a first step to implementing a conservation policy to manage reptiles such as chameleons, it is necessary to have some understanding of the use of natural habitats available to them.
No other known studies have been conducted on the ecology of chameleons in the Mpumalanga Province of South Africa and this study is the first at Telperion.
1.3 STUDY OBJECTIVES
The main objective of this study was to investigate habitat utilisation, seasonal distribution, dispersal, activity patterns and sexual dimorphism of C. dilepis on Telperion nature reserve
The study objective raised the following research questions:
1. In which habitats do C. dilepis occur on Telperion and what are the characteristics of these habitats? 2. Does C. dilepis utilise available habitat units in proportion to their availability? 3. Does C. dilepis show changes in seasonal distribution and life cycle stage occurrence? 4. Are there seasonal differences in the activity patterns of C. dilepis? 5. What are the dispersal patterns of C. dilepis within the study area? 6. Are there morphological differences between male and female C. dilepis? 7. Does temperature, rainfall or photoperiod influence presence of C. dilepis?
19 1.4 DISSERTATION OUTLINE
The content and outline of this dissertation are described below: 1. Chapter 1 contains the introduction to the study and provides a general overview of reptiles and lizards. A literature overview of the biology of chameleons and a description of the study species C. dilepis is also included 2. Chapter 2 describes the study area Telperion Nature Reserve with regard to geology, climate, soils, vegetation, topography and hydrology as well as a brief history of the area. Chapter 2 also includes the methods used to collect the data for the study 3. Chapter 3 provides the results and discussion of the habitat classification and describes the different habitat characteristics in terms of vegetation structure, vegetation cover, vegetation densities, soil characteristics, rockiness, herbaceous and woody layers. 4. Chapter 4 provides the results of data collected on C. dilepis. Information includes morphological measurements of C. dilepis, habitat utilisation and distribution of different age-sex classes in available habitats. Information on the perch plant height and perch plant species is also provided 5. Chapter 5 contains a comprehensive discussion and integration of chapter 3 and chapter 4 to suggest the seasonal preference and/or avoidance by C. dilepis of available habitats by different age/sex classes. 6. Chapter 6 concludes and summarises the study and provides management recommendations towards the conservation of C. dilepis on Telperion. Suggestions for future research are also provided.
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25 KEREN-ROTEM, T., BOUSKILA, A., & GEFFEN, E. (2006). Ontogenetic habitat shift and risk of cannibalism in the common chameleon (Chamaeleo chamaeleon). Behavioural Ecology and Sociobiology. 59, 723-731.
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26 MEASEY, G. J., HOPKINS, K., & TOLLEY, K. A. (2009). Morphology, ornaments and performance in two chameleon ecomorphs: is the casque bigger than the bite? Zoology. 112, 217-226.
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30 CHAPTER 2 - STUDY AREA AND METHODS
2.1 STUDY AREA
2.1.1 History of the study area
Telperion Nature Reserve (hereafter referred to as Telperion) is located between S25° 38' 32.42", E28° 58' 41.98" and S25° 44' 19.00", E 9° ' . 6‖ within the Mpumalanga Province of South Africa. Telperion is approximately 24 km northeast of Bronkhorstspruit and 29 km northwest of eMalahleni (formerly known as Witbank) (Figure 2.1). Telperion comprises the farms Blaauwpoort, Kranspoort and Sterkfontein (Chief Directorate: Surveys & Mapping, 2005) which were purchased by the Oppenheimer family between years 1974–1988and is still in the Oppenheimer family’s ownership today (Helm, 2006) and is used to house many conservation- related research projects. Agriculture was the main historical land use on Telperion and old fields and infrastructure used for agricultural practices are still noticeable (pers. obs.). Various forms of rock art and graffiti on topographical features in and around Telperion provide historical evidence of occupation by people (Forssman & Louw, 2016). Rock art by Bushman, Khoekhoe and Sotho-Tswana people, as well as refuges during the South African war where caves and overhangs were used by women and children hiding from the English soldiers can be found in the study area.
31
Figure 2.1: Location and boundary of Telperion in relation to the rest of South Africa.
2.1.2 Landscape and topography
The majority of the Telperion landscape consists of grassland plains and valley- bottom areas with rocky outcrops covered by woody vegetation in-between (Helm, 2006). Altitude ranges from 1200 meters above sea level at the lowest point to 1500 meters above sea level at the highest (Helm, 2006). The landscape of Telperion consists of undulating hills sloping gradually down to the Wilge River, which forms the western boundary of Telperion, with gradual open plains. The landscape in the southeastern section of the reserve is mostly rocky cliffs where the flow of the Wilge River through the reserve has resulted in natural long-term erosion that formed ridges and plateaus to form the basic topography of Telperion (Helm, 2006, Swanepoel, 2006).
32 2.1.3 Geology and Soils
Telperion is underlain by rocks of varying ages with the oldest rocks consisting of the Waterberg Group overlain by Karoo sediments (Mahanyele, 2001) (Figure 2.2). The Waterberg Group occurs in the centre of the Gauteng and Northwest provinces of South Africa and stretches into eastern Botswana. The Waterberg Group geological formation was formed 1800–1700 million years ago (Snyman, 1996) and is located in the Warmbaths basin and the Middelburg basin (Callaghan & Brand, 1991). Sediments of the Waterberg Group in the vicinity of Telperion consist of conglomerate, grit, sandstone and quartzite with underlying shale (Visser, 1961). The colours of these rocks range from reddish-brown to purple and the texture of the rock is medium to coarse-grained. Sandstone, quartzite based sandstone, grit, conglomerate and shale predominates (Visser, 1961, Land type Survey Staff, 1987). The reddish colour of some of the rock is distinctive of the rock types and originates from the high concentration of iron oxides in the rock (Viljoen & Reimold, 2002). Soil quality fluctuatesand formations of shallow soil forms such as Glenrosa and Mispah are typical on rocky ridges (Mucina & Rutherford, 2006). In other areas where deeper soils occur, soils are sandy to sandy loam, sandy clays and some clay (Mucina & Rutherford, 2006). The sandy soils have a deep Apedal B structure and vary from yellow to yellow-brown to brown and red Apedal B soils (Land Type Survey Staff, 1987). Soils in the riparian areas of the reserve vary from clay to shallow sandy alluvial and humus deposits (Swanepoel, 2006).
33
Figure 2.2: The underlying geology of Telperion (Johnson & Wolmerans, 2008)
2.1.4 Vegetation
The broad vegetation structure on Telperion was classified by Acocks (1988) as Bankenveld (Veld type no 61) whereas Low & Rebelo (1996) referred to this grassland as Rocky Highveld Grassland and Moist Sandy Highveld Grassland (LR 34 & 38). The most recent broad classifications of the area in and around Telperion have been identified by Mucina and Rutherford (2006) as Rand Highveld Grassland (Gm 11) and Loskop Mountain Bushveld (SVcb 13) (Figure 2.3), which are associated with very rocky areas on the steep slopes where trees were most likely protected from fire (Mucina & Rutherford, 2006).
34 Rand Highveld Grassland
Loskop Mountain Bushveld
Rand Highveld Grassland
Loskop Mountain Bushveld
Rand Highveld Grassland
Figure 2.3: Main vegetation types of Telperion (Mucina & Rutherford, 2006).
2.1.4.1 Rand Highveld Grassland
Rand Highveld Grassland (GM 11) is located in the most northern part of the Grassland Biome, with the most western part linked to the Kalahari, the most eastern section connected to the Drakensberg and the most northern part connected to the Savanna Biome (Bredenkamp & Brown, 2003). The Rand Highveld Grassland has a highly variable landscape with extensive sloping plains and ridges that are slightly elevated and surrounded by undulating plains (Mucina & Rutherford, 2006). Within this vegetation type, a sparse and tall tufted type grassland with forbs playing an important role (Acocks, 1988) as well as mixed sweet and sour veld (although mostly sour) (Mucina & Rutherford, 2006) occurs. Vegetation in this vegetation type is species-rich with alternating grassland with shrubland on rocky outcrops that have sparse woodlands ending in steeper slopes (Mucina & Rutherford, 2006). The Rand Highveld Grassland is endangered and due to agriculture and mining, only 1% of the vegetation type is formally protected for conservation (Mucina & Rutherford, 2006, Coetzee, 2013). Although some grassland at Telperion has been transformed by
35 previous tilling and agricultural activities, more than half of the area is still intact with all grassland habitats within the reserve now protected.
2.1.4.2 Loskop Mountain Bushveld
Loskop Mountain Bushveld (SVcb 13) occurs on the rocky slopes and ridges of Telperion, with open tree savanna in the lower-lying areas and denser broad-leaved tree savanna on the lower and mid-slopes (Mucina & Rutherford, 2006). Loskop Mountain Bushveld woodlands are mainly found on rocky slopes and in ravines where there is protection against fire and frost. Loskop Mountain Bushveld is characterised by the dominance of the tree Burkea africana in lower-lying areas and Diplorhynchus condylocarpon, Combretum apiculatum, Protea caffra, Combretum apiculatum and Senegalia caffra on mid-slopes (Mucina & Rutherford 2006). The herbaceous layer is dominated by the grasses Loudetia simplex, Trachypogon spicatus and Aristida transvaalensis (Mucina & Rutherford, 2006).
2.1.5 Climate and rainfall
Telperion is located within the summer rainfall area of South Africa and is characterised by warm temperate summers and cool to very cold and dry winters (Mucina & Rutherford, 2006). The annual rainfall ranges from 570 mm to 730 mm (Mucina & Rutherford, 2006) with the wettest month usually during January and the driest during July (Helm, 2006). This corresponds to the South African Weather services data that measured an annual rainfall of 645 mm in 2016 for the Bronkhorstspruit area (SA Weather Service, 2016). Summer maximum temperatures in the study area can reach up to 37oC while temperatures can drop to -13oC in winter, with the mean annual temperature reaching 16oC (Helm, 2006).
2.1.6 Drainage
The Wilge River, Laurilynspruit and Saalboomspruit are the perennial water sources flowing through the reserve (Figure 2.4). The Wilge River flows from south to north along the western boundary of Telperion, while the Laurilyn Spruit flows from east to west until it confluences with the Wilge River. The Saalboomspruit confluences with
36 the Wilge River in the south-western corner of the reserve where it forms a deep canyon-like gorge (Swanepoel, 2006). The Wilge River flows into the Olifants River which forms part of the greater Olifants River catchment that feeds Loskop Dam (Dabrowski & De Klerk, 2013). Although dams historically used for agricultural irrigation can still be seen along the Laurilynspruit, most of them have become derelict and overgrown with reeds and hold little water (pers. obs.)
Figure 2.4: Perennial watercourses and drainage lines on Telperion Nature Reserve (QGIS, 2009)
2.1.7 Alien Plants
Alien and invasive plants are plants that are exotic, non-indigenous or non-native to an ecosystem that can outcompete and replace indigenous species (Lotter et al., 2014). Some alien plants may spread aggressivelyand threaten indigenous ecosystem functioning and biodiversity (NEMBA, 2004). On Telperion dense stands of established Populus alba and Acacia mearnsii are the most noticeable alien plants. The greatest threat to the ecosystems at Telperion is category 1a and 1b
37 invasive plants (NEMBA, 2004) that have been observed during the growing season. They include Campuloclinium macrocephalum, Solanum sisymbriifolium, S. mauritianum, Opuntia ficus-indica, Cereus jamacaru and Jacaranda mimosifolia. Alien vegetation clearing and eradication is an integral part of the Telperion management plan and on-going activity on the reserve.
2.1.8 General animal species
Telperion contains approximately 250 species of birds and a variety of large mammals consisting of 22 species of large herbivores, 2 species of primate and 8 species of large carnivores (Helm, 2006). There is no known database for reptiles. The most noticeable large herbivores consist of the Common Eland (Taurotragus oryx), Greater Kudu (Tragelaphus strepsiceros), Blue Wildebeest (Connochaetes taurinus), Black Wildebeest (Connochaetes gnou), Blesbok (Damaliscus pygargus phillipsi) and Burchell’s Zebra (Equus burchellii). Primate species found at Telperion is the Chacma Baboon (Papio ursinus) and the Vervet Monkey (Chlorocebus pygerythrus). The most common carnivores present at Telperion consist of Black- Backed Jackal (Canis mesomelas), Leopard (Panthera pardus), Brown Hyena (Parahyaena brunnea), Caracal (Caracal caracal) and African Civet (Civettictis civetta).
2.2 METHODS
2.2.1 Vegetation ecology
This section describes the study methods for collecting data to identify and describe different C. dilepis habitats and its characteristics at Telperion.
2.2.1.1 Vegetation data collection
Using 1:50 000 stereo aerial photographs, Telperion was delineated into four physiographic-physiognomic units based on vegetation and topography as described by Edwards (1983), Brown et al. (1997) and Brown et al. (2013). The major structural
38 units identified were wetland, riparian, woodland and grassland. The reserve was traversed by vehicle to become familiar with the different habitat types present. To ensure that the major structural units present were investigated as possible reference sites for chameleons, 43 sample plots of 400 m2 were placed in a randomly stratified manner within each of the above-mentioned units. The location of each sample plot was recorded using a Garmin e-Trex Legend® HCx GPS receiver. Vegetation sampling was conducted following the Braun–Blanquet (Zurich– Montpellier) method (Mueller-Dombois & Ellenberg, 1974). In each sample plot, all plant species were identified and assigned a cover-abundance value using the Braun-Blanquet cover-abundance scale (Table 2.1). Photographs were taken of plant species that could not be identified and sent to experts for identification.
Table 2.1: Braun-Blanquet cover-abundance scale used in this study (Mueller- Dombois & Ellenberg, 1974) Scale DESCRIPTION r One or few individuals with less than 1% cover of the total sample plot area + Occasional and less than 1% cover of the total sample plot area Abundant with low cover, or less abundant but with higher cover, 1-5% 1 cover of the total sample plot area Abundant with >5-25% cover of the total sample plot area, irrespective of 2 the number of individuals >25-50% cover of the total sample plot area, irrespective of the number of 3 individuals >50-75% cover of the total sample plot area, irrespective of the number of 4 individuals >75% cover of the total sample plot area, irrespective of the number of 5 individuals
Environmental data collected in each of the study plots included slope (using a clinometer), aspect (using a compass), rockiness (percentage estimation), soil depth (using a soil auger), soil texture (clay, sand, loam) and signs of erosion. Rainfall data for the study period were collected from 16 rainfall gauges situated within different sections of Telperion.
Woody plant densities were determined using a belt transect of 2 x 100 meters (Barbour et al., 1999) within each of the study plots. In each belt transect, all the
39 woody species were identified and counted. Woody species were classified as shrubs (<1. m in height) or trees (≥1. m in height). Height and canopy volume of the woody vegetation was calculated for each height class using the Volcalc programme (Barrett & Brown, 2012). Three individuals of each height class that were representative of the majority of the trees and shrubs of the community were selected and measured to determine the average canopy volume for the stratum as described by Smit (1996).
Species diversity was determined for the seven habitat units using Menhinick’s Index ( ) (Whittaker, 1977; Mirzaie et al., 2013) and species richness was determined using Margalefs Index for species richness using the number of species in each habitat unit (Brower et al., 1997).
√
For both the Menhinick’s and Margalefs Indexes the values of is the number of taxa and is the number of individuals in a habitat.
The Shannon-Wiener Index of diversity ( ) and the Rich-Gini-Simpson Index of diversity ( ) (Guiasu & Guiasu, 2010) was calculated for each of the seven habitat units (Panicum maximum–Combretum erythrophyllum woodland, Imperata cylindrica–Populus alba woodland, Acacia mearnsii woodland, Loudetia simplex– Englerophytum magalismontanum woodland, Eragrostis curvula–Stoebe vulgaris grassland, Fadogia homblei–Burkea africana woodland, Eragrostis curvula– Eragrostis gummiflua grassland) that were derived from the four physiographic- physiognomic units
∑
∑
40 2.2.2.2 Vegetation data analysis
Vegetation data was captured using the TURBOVEG data management programme (Hennekens, 1996) and exported as a Cornell Condensed species file into the JUICE 7.0 Software Programme (Tich , 2002) for floristic data analysis. A modified TWINSPAN classification (Rolecek et al., 2009) was performed on the dataset to derive a first approximation of the major plant habitats. Whittaker’s beta-diversity, with the following pseudospecies, cut levels 0-5-15-25-50-75 was used (Brown et al., 2013). No further analysis was done if the dissimilarity was lower than three. The final phytosociological table obtained was refined following the Braun-Blanquet procedures as described in Brown et al. (2013). No relevés were moved, but only the species groups were arranged to improve the ecological interpretation of the habitats.
Woody species density was calculated by converting the number of woody plants (shrubs and trees respectively) counted in every 200 m2 plot to density per hectare by using the following formula (Nkosi et al., 2016)
To determine canopy volume of the woody vegetation the digital images of each woody species were imported into the Volcalc software programme (Barrett & Brown, 2012).
Cover-abundance data collected using the Braun-Blanquet surveys were transformed to a numerical scale (r=0.5, += 1, 1 = 2, 2 = 17.5, 3 = 35, 4 = 70, 5 = 140) to calculate species diversity and evenness (Van der Maarel, 2007). The results from the Shannon-Wiener diversity indices were converted to true diversities as described by Jost (2006) to give them values and properties that allow for appropriate comparisons between habitats.
41
( ∑ )
The plant species similarity between habitat units was measured using the Jaccard Similarity index using Microsoft Excel (Gardener, 2017). The shared species in each habitat unit was sorted in Microsoft Excel and the Jaccard similarity was calculated using the following formula:
Where = shared species and and are the species richness of the two samples being compared (Gardener, 2017).
2.2.2 Chameleon ecology
This section describes the study methods for collecting data on the ecology of C. dilepis at Telperion.
2.2.2.1 Chameleon data collection
Based on the habitat unit classification as described in the previous section (vegetation ecology data collection and analysis) and chapter 3, a total of fourteen survey plots of 10 000 m2 were randomly placed within the seven identified habitat units (Panicum maximum–Combretum erythrophyllum woodland, Imperata cylindrica–Populus alba woodland, Acacia mearnsii woodland, Loudetia simplex– Englerophytum magalismontanum woodland, Eragrostis curvula–Stoebe vulgaris grassland, Fadogia homblei–Burkea africana woodland, Eragrostis curvula– Eragrostis gummiflua grassland) on Telperion. Two plots within the riparian habitat (250 m x 40 m) were placed linearly within this habitat to survey the area along the river and contained two transects of 20 m wide. Plot sizes of 100 m x 100 m were placed in each of the remaining six habitats and each habitat had four transects of 20 meters wide. Data collection took place from July 2016 to July 2017 and included one wet (October to April) and one dry season (May to September). This season
42 allocation was based on climatic diagrams and mean annual precipitation (MAP) for the study area as described in Mucina and Rutherford (2006).
Surveys for C. dilepis took place at night (Dodd, 1981; Hebrard & Madsen, 1984; Tolley & Burger, 2007; Tolley et al. 2006; Tolley et al. 2010) using a Zartek™ ZA-465 500 lumens handheld spotlight. Chameleons are generally inactive at night and rest on vegetation with their skin colour being quite pale (cream to almost white, some bright yellow) that makes them more visible using a light source when perching on vegetation (Tolley & Herrel, 2014).
Transects within each survey plot were walked every two weeks using a handheld GPS to ensure consistency during surveys. Chameleons sighted within the 20 m transects were documented. It was assumed that a chameleon’s nighttime perch site reflected day time use of the same area (Da Silva & Tolley, 2013). For each chameleon found during a survey, the GPS position, habitat, plant species on which the chameleon was foundand the height perched (in meters) was recorded.
For those chameleons that could be caught (were not too high in the vegetation), their weight (g) using a 500 g PRESOLA® spring scale was determined by placing them in a perforated plastic bag to prevent them from escaping. The scale was set to zero after the bag was attached to account for the additional weight before a chameleon was weighed. Sex and various morphological measurements of chameleons were recorded as follows using a 300 mm flat plastic measuring stick: Snout-vent length (SVL) and Snout-tail length (STL) was measured (in millimetres) (Figure 2.5).
43
Figure 2.5: Morphological measurements made on C. dilepis for this study as adapted from Norval et al.,(2014)
Sexual differentiation was made by the presence of a thickening of the tail (hemi- penal bulge caused by the male hemipenes) in males which is absent in females (Tolley & Burger, 2007; Le Berre & Bartlett, 2009). In addition to the hemi-penal bulge, male C. dilepis have an extension of the tarsal bone at the back of the hindfoot called a tarsal spur (Wager, 1983, Tolley & Herrel, 2014) (Figure 2.6).
44 Hemipenal bulge that contains male reproductive organs
Tarsal spur on the hind foot of a male Chamaeleo dilepis
Figure 2.6: Tarsal spur on the hind foot and thickening in the tail caused by the hemipenes observed on a male C. dilepis at Telperion. Photo by T. L O’Donoghue
Individual C. dilepis were allocated to one of three age classes according to their measurements and physical appearances (hatchling, sub-adult and adult). Hatchling C. dilepis were categorised as not having a well-developed neck flap, a rounded head and occurring together in a group around the nest site (Tolley & Burger, 2007). Individuals that were measured with STLs between 37 mm and 42 mm (Wager, 1983) and an STL between 45 mm to 50 mm were regarded as juveniles (O’Donoghue, 1 , unpublished study). Chameleons were categorised as sub- adults when they had a total SVL length of > mm and ˂ 8 mm in females and an SVL of > mm and ˂ 6 mm in males ( eany et al., 2012). Sexually mature C. dilepis were documented as adults when they had a minimum SVL ≥ 80 mm in females and ≥ 6 mm in males (Reany et al., 2012).
Maximum and minimum temperatures in survey plots were measured using iButton- temperature loggers from Clima-Stats (via Fair-bridge Technologies). The temperature loggers were placed in each of the study plots and programmed to
45 record temperatures at hourly intervals for the duration of the study. Rainfall during the study period was recorded by rain gauges on Telperion.
Any nest sites located during the study were recorded and monitored as follows: The circumference and surface areas of nest sites and hatchling dispersal were measured by taking GPS readings. On the first night that a nest site was found, GPS readings of the hatchlings furthest from the nest The following night the same procedure was followed by recording all the hatchlings furthest from the original nest location. This was done for three consecutive nights and followed up again after 12 nights using the same method.
2.2.2.2 Chameleon data analysis
For the morphological comparisons and perch height between sexes within each age class and all age classes combined, data were tested for normality using the Shapiro–Wilk test. For normally distributed data the t-Test for unmatched pairs was used whereas for non-normally distributed data the non-parametric Mann-Whitney U test was used. All tests used to compare the differences in morphological measurements of C. dilepis were done at a 95% confidence level.
The utilisation by C. dilepis of the seven identified habitat units was investigated by determining the proportion of observed utilisation in relation to the availability of each habitat unit using the technique described by Neu et al. (1974). The proportion of each habitat available to C. dilepis within the study area was calculated by measuring the surface area of the available habitat unit. Bonferroni confidence intervals were generated for each habitat to determine if utilisation of the various habitat units was significantly different from what was expected based on the availability of the habitat unit. The confidence level was set at 95%
Data from the iButton temperature loggers were downloaded using Environmental Monitoring Software, Version 4 by Fair-Bridge Technologies. The mean, minimum and maximum temperature recorded in the study plots were calculated from this data. The mean annual rainfall during the study period was calculated from the data collected by the rain gauges during the study period. These values were compared
46 to the minimum, maximum and mean temperatures to determine if there was any correlation between the presence and absence of C. dilepis during different times of the year. A histogram was compared to the Mean Annual Precipitation (MAP) and temperature to see if there was any relationship between the MAP, temperature and presence of C. dilepis during the dry and the wet season.
The General Additive Model was used in R (R Core Team, 2013) to determine if there was a statistical significance between recorded temperature, photoperiod, rainfalland the presence or absence of C. dilepis during the study period.
Data collected on the hatchling movement away from nest sites were analysed by connecting the coordinates recorded during each sampling day and drawing a polygon. The surface areas of the polygons were determined by QGIS Desktop software version 2.6.1 and the increase in nest site dispersal was then determined by subtracting the smaller polygon sizes form the largest one.
Plants species perched on were compared with the cover-abundance scales from the Braun-Blanquet method within each habitat unit. The Braun-Blanquet values were tabulated and perching plants were divided into different structures such as woody plants, grasses, dwarf shrubs and forbs. All the data were compared to the use of the perch plants in each of the chameleon age classes to determine if C. dilepis utilise plants to perch based on canopy cover and abundance or plant structure during different stages of its life cycle.
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52 CHAPTER 3 – HABITAT CLASSIFICATION AND DESCRIPTION
3.1 INTRODUCTION
The Mpumalanga Province has a great diversity of plants and animals with an estimated 4300 plant, 173 mammals, 171 reptiles, 575 bird, 62 fish, 51 amphibian species and an unknown number of invertebrate species (MPTA, 2014). The province only occupies 6% of the South African land surface and accounts for approximately 21% of its plant species diversity and contributes significantly to high levels of endemism in plants (Lötter et al., 2014).
A well-known method of conserving this diversity is by establishing a network of protected areas or nature reserves that are representative of the biodiversity throughout the landscape (Ferrar & Lötter, 2007). Telperion is such a nature reserve and is located within the endangered and largely overexploited Grassland Biome (Swanepoel, 2006). The area is characterised by its rocky outcrops and ridges similar to the vegetation of the Magaliesberg and Suikerbosrand Nature Reserve (Swanepoel, 2006). The area is located within the Bankenveld region of South Africa as described by Acocks (1988) and Bredenkamp & Brown (2003). According to the latest vegetation map of South Africa, the area is classified as belonging to the endangered Rand Highveld Grassland (Gm 11) (Mucina & Rutherford, 2006). Bankenveld is characterised by a complex topography with the rocky hills, outcrops, grassland plateaus all creating a large variety of microhabitats (Bredenkamp & Brown, 2003) that is reflected in the presence of a large diversity of plant communities (O’Connor Bredenkamp 3). Bankenveld vegetation consists of an assortment of grassland and woodland communities controlled by climatic conditions that exist in the topographically diverse landscape in the transition zone between the Grassland and Savanna biomes. (Bredenkamp & Brown, 2003).
To enable managers to efficiently manage and conserve species in any nature reserve, knowledge of the ecology of the area and an inventory of the living and non- living resources is an essential requirement (Van Staden & Bredenkamp, 2005). With
53 this knowledge, one is able to develop appropriate scientific management plans (Marais et al., 2005).
Van Staden and Bredenkamp ( ) state that ―natural systems‖ as they occur today cannot be viewed and conserved as ―natural‖ anymore, due to the influence humans have and are still having, on ecosystems. In most cases, these areas need to be managed on the basis of interpreted ecological knowledge to be able to restore the balance that existed in the original natural system. Studying and collecting vegetation data can assist reserve managers or researchers in finding solutions to specific environmental or conservation problems (Kent & Coker, 2000). The basis of any ecological management plan and the interpretation of the ecosystem are the identification, classification and description of the different plant communities, their environmental conditions and/or interactions with different animals, as well as their potential habitat for different animals (Kent & Coker, 2000). Within each ecosystem (plant community) each species has its own requirements for natural and other resources, some which may limit the population size and distribution of a species (Primack, 2012). Plant communities and their associated vegetation maps are therefore regarded as reliable replacements for the demarcation of ecosystems (Brown et al., 2013). If these ecosystems and their different potentials are not known, they cannot be managed successfully (Brown & Brand, 2004).
No animal or plant lives or functions in isolation and ecosystems are functional ecological units that interact within a reasonably well defined physical and climatic environment (Van As et al., 2012). It is therefore apparent that different animal species occupy and utilise various ecosystems such as different plant communities for various activities such as sleeping, feeding and reproducing (Sinclair et al., 2006; Van As et al., 2012). The study of the vegetation of the home range of animals must form the basis when the ecology, social interaction and dietary requirements of animals are studied (Brown, 2003).
Chameleons have evolved a unique set of traits that allow them to occupy a highly specialized niche (Reaney et al., 2012). The classification and description of the different habitats that chameleons occur in will provide a better understanding of their habitat preferences and avoidances and therefore habitat requirements. The
54 aim of the vegetation study was to identify and describe different habitats potentially available to chameleons on Telperion. The methods for the vegetation description were described in chapter 2.
3.2 RESULTS
3.2.1 Vegetation classification
The anthropological history, topography and climate of Telperion gave rise to four broad physiognomic plant units namely: wetland, riparian, woodland and grassland associated vegetation. Sections of the grassland areas have been affected by past agricultural practices and are regarded as secondary successional grasslands. Natural grasslands that were left intact occur on shallow rocky soils. Although some of the woodland areas on Telperion occur in the open grassland areas with deep sandy soils, the majority of the woody vegetation is confined to rocky slopes and riparian areas where they are protected from fire and severely cold temperatures.
The vegetation surveys of the four identified large physiognomic units of Telperion (wetland, riparian, woodland and grassland) resulted in the identification of seven habitat units:
1. Panicum maximum–Combretum erythrophyllum woodland 2. Imperata cylindrica–Populus alba woodland 3. Acacia mearnsii woodland 4. Loudetia simplex–Englerophytum magalismontanum woodland 5. Eragrostis curvula–Stoebe vulgaris grassland 6. Fadogia homblei–Burkea africana woodland 7. Eragrostis curvula–Eragrostis gummiflua grassland
All species groups are presented in Table 3.1 and therefore no specific reference will be made to the table in the description of the various habitat units which are described in detail after Table 3.1
55 Table 3.1: Phytosociological table of the different habitat units studied at Telperion.
HABITAT NUMBERS 1 2 3 4 5 6 7 1 4 3 1 3 1 4 3 2 3 1 3 1 2 3 3 3 2 2 2 1 1 3 1 1 2 4 1 2 4 2 3 2 2 1 7 6 3 5 8 1 2 4 Releve numbers 1 3 5 1 9 9 2 4 0 6 2 5 0 6 2 1 0 2 8 7 7 6 6 4 8 5 1 3 9 0 1 3 4 3 5
Species group A Combretum erythrophyllum 4 4 1 + ...... + ...... Panicum maximum 1 1 1 + ...... r . . r . r ...... Sporobolus africanus 2 2 . + . . . + . . + ...... + . r + . . 2 ...... Eragrostis inamoena 1 1 . + . . . + + . + ...... 2 ...... 2 2 . r . + . Paspalum urvillei 1 1 . 1 . . . 2 . . 2 . . r . . . . + . . + ...... Paspalum dilatatum + + . + . . . + . . + ...... Persicaria lapathifolia + + . + . . . + . . + ...... Monopsis decipiens r r . + . . . + . . + ...... + ...... Eriosema salignum 1 1 ...... Zinnia peruviana + + ...... r ...... Melia azedarach r r . + + + ...... Acacia karroo r r ...... Achyranthes aspera v. aspera + + ...... Celtis africana r r + ...... + . . r ...... + ...... Eucalyptus camaldulensis + + . . . . . + . . . . . r ...... 1 . . . Lippia javanica r r ...... Nemesia fruticans r r . + ...... + ...... + . . Salix babylonica + + ...... Verbena brasiliensis r r ...... Populus nigra + + ......
Species group B Populus alba . . . . 3 3 4 4 . . 4 ...... r ...... 1 . . . . . Miscanthus junceus . . + 2 2 2 . + . . + ...... Helichrysum setosum . . . . r r . + . . + ...... + ...... Pennisetum macrourum . . . 2 . . . 3 1 . 1 ...... Hyparrhenia hirta . . . . . r . + . 3 + ...... 1 + ...... + . r . + .
Species group C Phragmites australis 2 2 2 3 3 3 2 4 4 . 4 . . r ...... Imperata cylindrica 1 1 . 3 . . 1 2 1 r 2 ...... + . . . . 1 . . . + + . . . . . Phragmites mauritianus + + . . 1 1 + ......
Species group D Acacia mearnsii r r 2 + . + . . . . . 5 4 1 ...... 2 ...... Bidens pilosa + + r . r r . . . . . 1 1 r . + r r r r . . . r . + ......
Species group E Loudetia simplex ...... 2 . 2 2 . 2 2 2 3 2 3 2 ...... 2 r . . 2 Combretum molle ...... r 2 2 2 1 2 2 r . + 2 r r + ...... + . . + . . . . Englerophytum magalismontanum ...... r 1 + 2 1 1 1 + + + 1 1 + ...... r r + . + . . Setaria lindenbergiana . . + ...... 1 + 1 1 1 2 1 . + + . r + ...... Croton gratissimus ...... 2 2 + 2 . 3 2 . r + ...... Aristida transvaalensis ...... r 1 . 2 r . r 1 r . . 1 + ...... + . + . 1 Elephantorrhiza burkei ...... r 1 2 r + 1 + . . + . . + ...... + . . + . Strychnos pungens ...... r . 1 . r . r + . + 2 2 2 ...... 1 . . . . Xerophyta retinervis ...... r + r r . r r . + r + 1 ...... r ...... r + . + Euclea crispa ...... r . . r r + + + . . . r + ...... 1 ...... Commelina africana ...... r + . r + r r . + r r + ...... + r r + . + . . Stylochiton natalensis ...... + r + r r + . + r r + ...... r r + . . . . Searsia magalismontana ...... 2 . r r . r 1 + + r 2 + ...... + . . . . Gymnosporia buxifolia 2 2 . 1 ...... + 1 r + . + . + . 1 + ...... + . . . r r + . . . + Dombeya rotundifolia ...... r . + . r 2 r 1 + + . . + ...... Trachypogon spicatus ...... r . r r . 2 . . . r 1 1 ...... r r . . . + . Ozoroa paniculosa ...... r 1 r r . + + . . + ...... r . . . Canthium gilfillanii ...... r . . r . . . . + + ...... Pappea capensis . . + ...... r . + . . r r ...... Searsia leptodictya ...... r . + r + + r 2 + + ...... + ...... Andropogon schirensis ...... + . . r ...... + ...... Eragrostis nindensis ...... r . r . . + ...... + . . . . Indigofera melanadenia ...... + . . . 1 r 1 + . . + ...... + . . Pavetta zeyheri ...... r . . . + r ...... Protea caffra ...... + . 1 + . . . . + . . . 2 1 ...... 1 . . . 1 Sphenostylis angustifolia ...... + . + r r ...... Zornia linearis ...... r + ...... + . r ...... r . . . . . + . . . . Aristida adscensionis ...... + . . . r . . . + ...... + ...... Brachiaria brizantha r r ...... r + ...... 1 . . . . . Brachylaena rotundata ...... r r + 2 ...... r r . . . . . Ficus ingens ...... r . . . . + . 1 ...... Heteropogon contortus ...... r . . . r . . . + ...... + . . + . Maytenus undata ...... r . . + . + r + ...... + . . . . Rhoicissus tridentata ...... r . + r . + r . . . . . + ...... Ziziphus mucronata r r . + ...... 1 . r . r ...... + ...... Plectranthus madagascariensis ...... + . r r ...... Asparagus suaveolens + + ...... r . . . r . + + . + ...... + + . . . . . Kalanchoe paniculata ...... r . . . r . . r . + ...... + . . . . Zanthoxylum capense ...... r r . r + . + . . + ...... Faurea saligna ...... r r . r . + ......
56 Cymbopogon poschpicillii ...... + . + + ...... Heteropyxis natalensis ...... 1 + . . + . + ...... r r . . . . . Cymbopogon caesius ...... r . . 1 . . . . . + + 1 ...... Ancylobotrys capensis ...... + r + . r . . . r ...... + r . . . Ectadiopsis oblongifolia ...... + r r . r . . + . . + ...... + . . . .
Species group F Stoebe vulgaris . . . + . . . + . r 1 ...... 4 2 . + + 3 . . . + r r . 2 . + . Pollichia campestris . . . + + + ...... + + + 1 . . . . . + . . + . + . r Aristida congesta s. barbicollis ...... + ...... r + ...... r 2 + ...... r . . + Diospyros lycioides + + . + ...... + ...... + . . r + ...... + Eragrostis rigidior r r ...... + ...... + 2 + + ......
Species group G Pteridium aquilinum r r . 1 ...... 5 5 ...... Lopholaena coriifolia ...... + + ...... + + + . . . + r . . . Hyperthelia dissoluta 2 2 ...... r . . . . . + 1 . . . . r r r + ...... Parinari capensis ...... + ...... + ...... r r r . . . + . . . . Crabbea angustifolia ...... + + ...... Digitaria brazzae . . . + ...... r r ...... Kalanchoe thyrsiflora ...... r r ...... Pentanisia angustifolia ...... + . + . . . . . + + ...... Sonchus dregeanus ...... + + ...... Tenaris rubella ...... r ...... r r ......
Species group H Protea welwitschii ...... + . . . + ...... + . . . r r + r . + + Dichapetalum cymosum + + ...... + ...... + . . . r r + r + + + Digitaria monodactyla ...... r r . r . . + Themeda triandra ...... r . r . . + r . + ...... + r r + r + + . Hilliardiella oligocephala ...... + . . . . + . . . r r . . + . . Nidorella anomala ...... + r . + . . . + ...... r r . . . + . Chamaecrista mimosoides . . . + . . . + . . + ...... + . + . . . . r r + . . + . Verbena bonariensis . . . + . . + + . . + ...... + + + ...... r r . . + + . Elionurus muticus ...... + ...... + r + 2 + Lotononis listii ...... + . . . . . r r + . . . + Microchloa caffra ...... + r . + + Monocymbium ceresiiforme ...... 1 1 . r . . + Oxalis depressa ...... + ...... r r + r . . . Pelargonium luridum ...... r r . . . + . Aristida junciformis ...... + ...... r r . r . + . Bulbostylis burchellii ...... r . . r ...... r ...... r r . r . . .
Species group I Tephrosia lupinifolia ...... + . . . r . . . r . + + . + + + . . . . + . . Acanthospermum australe ...... + . . + . . r + + + + . . . . . + r + r . Cleome hirta ...... + ...... + + + + . . . + . . + . Eragrostis plana ...... + . . + ...... r . . . 2 . . . r r . . . . . Gomphrena celosioides + + ...... r . . . r . . . r r . . + . . Aristida congesta s. congesta . . . + . . . . . 1 ...... + . . r . 2 2 . r r . . . . . 1 + + Eragrostis racemosa ...... + . . + . . 1 r . . . r r r . r r . r . + . Cleome maculata . . . . + + ...... + . . + . . r . . + . + + . . . + . + . . Solanum sisymbrifolium + + . + . . . + . . + ...... + . . r + + + . r r . . . + r + + .
Species group J Burkea africana . . . . . + ...... + . 2 + . 1 . . 2 1 1 3 + . . + . . . . + 2 2 3 . . 1 . + . 2 Fadogia homblei . . . + r r ...... + . r . . r 1 + + + r 1 + . . . . . 1 . 1 2 r r + r + + 2 Melinis repens r r . + r r ...... + + . r . r r . 1 r + + + + r + + + . . . + r r + r + + + Salacia rehmannii . . . + ...... + . . . . r 2 . . 2 + + . + r 1 . . . + + 2 . . + . . . 1 Aristida stipitata . . . + ...... r . . . . . r . + . . + . . r + + 1 r r r + . . + r + + + Bulbostylis hispidula ...... r . . . r r . + . + + + . + . . . r r + r r + r . . + Perotis patens . . . + r r ...... 1 r + . . . + + . 2 + + r r r . r r + r + + + Diheteropogon amplectens ...... 2 + . 2 . r 1 . + r 1 1 ...... r r r + r r 1 . + . + Ochna pulchra ...... + + r r r + 1 + + + 1 + ...... + + + . . + r . . . Schizachyrium sanguineum ...... + r r . r + . + r 1 + ...... + . . + r . + . Setaria sphacelata ...... + . r . r . . + r r + ...... 2 r r + . + + + Bidens bipinnata ...... 2 . . r r . . 2 ...... r r + . . . . Pellaea calomelanos ...... + + r r r r r r + r . + . . . . + . . r r + + + + r . . + Oldenlandia herbacea ...... + . . + . . . r . r r . . + . + + . + . . r . . . . r r . r r + r . r . Pogonarthria squarrosa . . . + r r ...... r . r . . . r r + . . . . + . + + + . r r + . . . r . . . Elephantorrhiza elephantina ...... r . r . . . . . + . r + ...... + r r . r + . + Cleome rubella ...... r . . . . . + . . + . . . . + + . + + ...... Senecio oxyriifolius ...... + + . r ...... + ...... r r ...... Tristachya rehmannii ...... + . . . . 1 r ...... + + . . . . . + . 1 Solanum panduriforme ...... + ...... 1 Triumfetta sonderi ...... r . . . . . + . . . . . 1 ...... Pearsonia sessilifolia ...... + ...... r . . . + ...... r r . . . . . Asparagus suaveolens ...... + ...... + ...... + . . + r . + . Indigofera comosa ...... r . . r . . . . . + . + . + . r . . . + ...... 1
57 Richardia brasiliensis ...... + ...... + . . + . . r . + + . . . + . . + r + + . Parinari capensis . . . . r r ...... 2 . + r ...... + + . . . + + + . r + + + Phyllanthus parvulus ...... r . + . r + . . . + + . + r r . . . . . + + . Selaginella dregei ...... r r . 1 . . + . 1 + ...... + r . . + Sida cordifolia r r ...... r ...... r . . . . + ...... + . . . . Mundulea sericea ...... + + . . . r + . . . . + ...... r r + . . . . Melinis nerviglumis ...... r + ...... r . + . + ...... r . . . Commelina erecta ...... r . . . . r ...... Cyanotis speciosa ...... + . . . . . r ...... r r . r + . .
Species group K Eragrostis gummiflua + + . + 2 . . + . 2 2 . . r . . r r 2 r 2 2 . . + + + 1 . . . + . . . 1 3 3 + 2 3 3 2 Cynodon dactylon 2 2 . 2 2 2 . . . . 1 . + . . . . . r . . . . . r . 2 . 4 3 + . r r r 1 1 1 . r + + 1 Eragrostis curvula + + . . 2 . . + . . + . . . + + r r r r + . + . r + + 2 r + 2 2 + r r + r r + 2 + 1 1 Polydora poskeana r r . + r r ...... r . r r + . . . . . + . + . . . r r + + + . r . . . Schkuhria pinnata r r . . r ...... r . r . r ...... + . . r . 1 . . . . . r r . . . . . Solanum incanum r r . + r r . + . . + . . . . + r . r r . . + . . + . . r + + . . r r . r r . . + 1 + Digitaria eriantha ...... + . . + ...... r ...... + + . . . + . r r ...... Hypoxis iridifolia . . . . r ...... r . . . + . + . . . r + ...... r r . . + r . + r Hypoxis rigidula . . . . + + ...... + ...... + . . + ...... r r + . . + . + + . Trichoneura grandiglumis ...... + . . + . . . + ...... + . r . . . . + + + . r r . . . . . + . + Tagetes minuta . . r ...... + + . . . r r + r ...... r r + . . . r . . . Olea capensis ...... + . . r ......
58 3.2.2 Habitat unit descriptions
1. Panicum maximum–Combretum erythrophyllum woodland
The Panicum maximum- Combretum erythrophyllum woodland habitat unit is located along the Wilge River with an altitude ranging from 1257–1310 meters above sea level (masl). The slope varies from steep rocky ledges where the river is deeply incised to mild slopes with the vegetated embankments with aspects predominately west facing. Soils are shallow sandy-loam to loam on hard rock and the rockiness of this habitat unit ranges between 1% and 20%.
Species from species group A are characteristic for this habitat unit. The vegetation is dominated by the tree Combretum erythrophyllum (species group A) and the reed Phragmites australis (species group C). The shrub Gymnosporia buxifolia (species group E) and the grasses Cynodon dactylon (species group K), Panicum maximum, Sporobolus africanus, Paspalum urvillei (species group A) and Imperata cylindrica (species group C) are prominent throughout this habitat unit. The grass Hyperthelia dissoluta (species group G) is prominent behind the tree line toward the more
59 terrestrial grassland edge where deeper sandy soils occur. The alien invasive tree Acacia mearnsii (species group D) is present throughout this habitat unit and prominent in some sections. The tree canopy cover is between 5 and 50% and the shrubs cover approximately 20%. The grass layer cover is between 15 and 80% and the forbs cover 15%.
As with all riverine systems, changes in water flow results in continuous erosion causing terraced embankments at different levels that include different species. The lowest part closest to the water’s edge is usually dominated by Phragmites australis and on the slightly more elevated embankment, the grass Cynodon dactylon is prominent while Panicum maximum is prominent under woody vegetation.
2. Imperata cylindrica–Populus alba woodland
The Imperata cylindrica-Populus alba woodland habitat unit is a wetland habitat that is located along seasonally wet tributaries and streams at altitudes of 1291-1388 masl. The aspect of this habitat unit varies but is mostly north and south facing. Rockiness varies and ranges from 1% to 75%. The soils show signs of moisture
60 throughout the year and are rich in organic and plant materials and have high clay content especially in the permanently wet areas. On more elevated areas of the habitat unit the soils are more sandy, leached and grey in colour.
Species from species group B are characteristic for this habitat unit and include the alien invasive tree Populus alba, the grasses Miscanthus junceus, Pennisetum macrourum, Hyparrhenia hirta and the forb Helichrysum setosum. The vegetation is dominated by the tree Populus alba (species group B) and the reed Phragmites australis (species group C). Other species that are locally prominent include the grasses Imperata cylindrica (species group C), Pennisetum macrourum (species group B) and the grasses Eragrostis gummiflua and Cynodon dactylon (species group K). Forbs such as Helichrysum setosum (species group B) and Nidorella anomala (species group H) are noticeable amongst the grass layer. The tree layer covers between 15% and 75%, the shrubs cover approximately 5%, the grass layer covers between 15% and 75% and the forbs cover 15%.
Phragmites australis is located around areas with permanent water and the alien tree Populus alba has established in large parts of the habitat unit where it forms tall dense thickets. The open areas are utilised by wildlife for grazing and drinking of water. Historical disturbances to the vegetation and soil profile (dams, infilling and trenching as well as construction of water channels to assist with the drainage of cultivated fields), has altered the soil in places and provided suitable conditions for shrubs such a Searsia pyroides (species group L) and Diospyros lycioides (species group F) to grow on the excavated soil mounds. Located on a relatively mild slope, there are places where the stream course is altered by steep rocky embankments.
61 3. Acacia mearnsii woodland
The Acacia mearnsii woodland habitat unit occurs as dense thickets at various intervals within the study area. Altitude ranges from 1258–1459 masl and aspects include northwest facing on slight slopes and mostly south facing on the rocky ridges. The slopes differ from slight in the grasslands too steep in the rocky woodlands. The soils are moderately deep but become shallow to the east. Soil texture is sandy to loam and the rockiness varies between 5% and 75%.
Species from species group D are characteristic of this habitat unit. Vegetation is dominated by the alien tree Acacia mearnsii (species group D) and the forb Bidens pilosa (species group D). Prominent species in this habitat unit include the grasses Cynodon dactylon (species group K) on sandy soils and Setaria lindenbergiana (species group E) on rocky areas. Prominent forbs are Tagetes minuta (species group L) and Dichapetalum cymosum (species group H). The tree layer covers 20% and shrubs have a cover between 5% and 15%. The grasses cover between 35% and 75% and the forb layer 30%.
62 Acacia mearnsii has the ability to grow in a variety of habitats and is therefore not limited to a specific slope, aspect or soil type and the plants form small to large bushy or woodland communities across the study area. Although efforts have been made to control Acacia mearnsii on Telperion, coppicing occurs and therefore forms dense stands of shrubs and saplings with little or no plants growing underneath the trees, leaving the soils bare and exposed in certain places with little herbaceous cover.
4 Loudetia simplex–Englerophytum magalismontanum woodland
The Loudetia simplex–Englerophytum magalismontanum woodland habitat unit occurs on the rocky slopes between the flat grassland crests and gently sloping valley bottom grasslands of Telperion. This habitat unit occurs at altitudes that range between 1357 and 1459 masl. The aspects of this habitat unit differ with sections facing north, east, south and west, although the majority faces north and south with a mild to a steep slope. Soils are shallow sandy-loam to loam and have high organic matter content. The habitat unit is rocky with large quartzite boulders covering between 15% and 70%.
63 Species from species group E are characteristic of this habitat unit. The vegetation is dominated by the tree Combretum molle, the shrubs Englerophytum magalismontanum, Croton gratissimus, Searsia magalismontana and the grass Loudetia simplex (species group E). The forb layer is dominant, well formed and Pellaea calomelanos (species group J) is prominent. Different slopes and aspects result in slight differences in the woody vegetation structure of this habitat unit. The woody layer has a canopy cover of between 10% and 60% and grass cover ranges between 10% and 70% with forbs between 5% and 30%.
Englerophytum magalismontanum, Combretum molle and Croton gratissimus (species group E) are abundant and dominant on the steep north facing slopes, the tall shrubs Protea caffra and Heteropyxis natalensis (species group E) are prominent and mostly restricted to the south-facing slopes. Other species that are prominent include the grasses Setaria lindenbergiana, Cymbopogon pospischilii (species group E) and Eragrostis gummiflua (species group K). Burkea africana shrubs (species group J) are prominent on the lower lying areas close to the valley bottom.
Where slopes are less steep and flatter, the north and south facing slopes are similar in vegetation composition. Other species that are prominent include the trees Strychnos pungens (species group E), Ochna pulchra (species group J), Searsia leptodictya, Ozoroa paniculosa, Euclea crispa and Gymnosporia buxifolia (species group E), grasses Loudetia simplex (species group E), Diheteropogon amplectens, Melinis repens (species group J) and Trachypogon spicatus (species group E). At intervals flat terrace forming quartzite outcrops that accumulate soil and organic matter in the basin like depressions in the rock are covered by the moss Selaginella dregei (species group J)
Where large boulders protrude, distinct clumps of specific trees grow. These include Maytenus undata, Searsia leptodictya, Ficus ingens (species group E) and Olea capensis (species group K). The herbaceous layer of these clumps have little or no grass cover but the forbs Stylochiton natalensis (species group E) and Salacia rehmannii (Species group J) grow well in these spaces. These areas are mostly undisturbed and are regarded as being in a natural condition.
64 5. Eragrostis curvula–Stoebe vulgaris grassland
The Eragrostis curvula-Stoebe vulgaris grassland habitat unit is located on the mid slopes toward or within the valley bottoms and frequently bordering the Imperata cylindrica–Populus alba woodland (habitat unit 2). It is found at elevations between 1327 and 1475 masl. The aspect varies from northwest to southwest with a slight slope but the terrain is mostly flat. The soils are deep sand to sandy-loam with a well-structured red, yellow to brown A-pedal B-horizon.
Species from species group F are characteristic of this habitat unit. Dominant species are the dwarf shrub Stoebe vulgaris (species group F) and the grasses Cynodon dactylon and Eragrostis curvula (species group K). The grass Melinis repens (species group K) and the forbs Acanthospermum australe (species group I) and Pollichia campestris (species group F) are constant species throughout this habitat unit.
Tree cover is absent but the dwarf shrub Stoebe vulgaris covers between 15% and 75% and grass cover range between 20% and 80%. The forb layer covers between 10% and 15%.
65 This habitat unit consists of open grassland that is in various phases of advanced or early secondary succession due to having been previously disturbed when the area was cultivated before incorporated into Telperion.
6. Fadogia homblei–Burkea africana woodland
The Fadogia homblei-Burkea africana woodland habitat unit is located in open grassland and located adjacent to the Loudetia simplex–Englerophytum magalismontanum woodland (habitat unit 4). This woodland is less dense than those found on the rocky slopes and is widespread on Telperion. It is located at elevations between 1341 and 1460 masl and is mostly flat though some areas have a slight south-western slope. The soils are deep sandy yellow-brown to loamy with no exposed rock.
Species from species group G are characteristic for this habitat unit. The vegetation is dominated by the tree Burkea africana (species group J), the grass Eragrostis gummiflua (species group K) and the forb Fadogia homblei (species group J). The forb Salacia rehmannii (species group J) is prominent and forms dense patches within the herbaceous layer. The geoxylic suffrutex, Parinari capensis (Species
66 group J) grows on the outer regions where the soils become shallower toward the Eragrostis curvula–Eragrostis gummiflua grassland. The grass Eragrostis curvula (species group K) is prominent in some areas and in some sections of this habitat unit where it is associated with drainage channels the forb Pteridium aquilinum (species group G) is dominant with Gomphocarpus glaucophyllus and Pentarrhinum insipidum (species group L) being prominent. The tree canopy cover is between 20% and 70%. The grasses have a cover of between 10% and 85% while the forb layer ranges between 5% and 75%.
7. Eragrostis curvula–Eragrostis gummiflua grassland
The Eragrostis curvula–Eragrostis gummiflua grassland is located close to the Eragrostis curvula-Stoebe vulgaris grassland along the edge of the plateau where the Loudetia simplex–Englerophytum magalismontanum woodland (habitat unit 4) is located. It consists of natural terrestrial grassland vegetation ranging from 1431 and 1490 masl. The terrain of this habitat unit is mostly flat though in some areas slight south-facing slopes form part of this grassland. The soils vary from moderately deep sandy to shallow loamy soils on hard rock. Rockiness varies between 0% and 50%.
67 Species from species group H are characteristic of this habitat unit. The vegetation is dominated by the grasses Eragrostis gummiflua and Eragrostis curvula (species group K) while the shrub Protea welwitschii (species group H) and the dwarf shrub Stoebe vulgaris (species group F) are prominent. The forb layer is patchy and dominated by Fadogia homblei (species group J) and Salacia rehmannii (species group J). Geophytic plants present in the rocky sections of this grassland include Hypoxis iridifolia, Hypoxis rigidula, Gladiolus ecklonii, Gladiolus elliotii, Boophone disticha and Lapeirousia sandersonii (species group L). The woody layer is mostly absent in this habitat unit, but shrubs that occur have a canopy cover ranging between 0% and 5%. Grasses cover between 50% and 95% of the area and the forbs between 1% and 15%.
This habitat unit is heavily grazed and as a result, trampled by herbivores. Woody vegetation is sparse but occasionally the tree Burkea africana (species group J) occurs where the soil is deeper while the shrub Gymnosporia buxifolia (species group E) is found in shallow soil on hard rock. Along the rocky edges of this habitat unit, drainage from the higher elevated rocky woodland communities creates a seasonal runoff. Drainage along the runoffs where rainwater sometimes accumulates causes soil to remain moist for longer during the season. The grasses Microchloa caffra, Monocymbium ceresiiforme (species group H) and Cynodon dactylon (species group K) are prominent in these sections.
3.2.3 Density, Canopy volume and Height of woody vegetation
The vegetation study of the different habitat units included an assessment of the woody plant density, height and canopy volume for each of the seven identified habitat units. Trees were recorded as woody species with a height of ≥1.5 m while woody plants less than 1.5 m were recorded as shrubs (Tainton, 1999). The results of the woody plant classifications in terms of density, canopy volume and mean height classes of woody species per habitat unit are presented in Table 3.2
68 Table 3.2: The density, canopy volume and mean height classes of woody species per habitat unit (*no woody species recorded)
Canopy volume Mean height Density (ind/ha) 3 Habitat unit (m /ha) (m) Trees Shrubs Trees Shrubs Trees Shrubs Panicum maximum–Combretum 231 386 15754.2 1351 5.3 1.5 erythrophyllum woodland Imperata cylindrica–Populus alba 891 1584 72438.3 2439.4 11.6 1.3 woodland Acacia mearnsii woodland 650 1500 50765 10650 6.4 1.4 Loudetia simplex–Englerophytum 644 1254 37996 1379.4 4.9 1 magalismontanum woodland Eragrostis curvula–Stoebe * 957 * 861.3 * 0.1 vulgaris grassland Fadogia homblei–Burkea africana 214 1039 28547.6 1766.3 8.3 1.1 woodland Eragrostis curvula–Eragrostis * 66 * 26.4 * 0.7 gummiflua grassland
3.2.4 Plant species richness and diversity
The Loudetia simplex–Englerophytum magalismontanum woodland (habitat unit 4) and the Eragrostis curvula–Eragrostis gummiflua grassland (habitat unit 7) have the highest species richness. This also reflected in both the Menhinicks’s and Margalef’s indices (Figure 3.1). Overall Eragrostis curvula–Stoebe vulgaris grassland (habitat unit 5) has the third highest species richness while the Imperata cylindrica–Populus alba woodland (habitat unit 2), Acacia mearnsii woodland (habitat unit 3) and the Fadogia homblei–Burkea africana woodland (habitat unit 6) has the lowest species richness.
In terms of species diversity the Loudetia simplex–Englerophytum magalismontanum woodland (habitat unit 4) and the Eragrostis curvula–Eragrostis gummiflua grassland (habitat unit 7) have the highest species diversity. The Eragrostis curvula–Stoebe vulgaris grassland (habitat unit 5) and the Panicum maximum–Combretum erythrophyllum woodland (habitat unit 1) have the third and fourth highest species diversity respectively the Imperata cylindrica–Populus alba woodland (habitat unit 2), Acacia mearnsii woodland (habitat unit 3) and the Fadogia homblei–Burkea africana woodland (habitat unit 6) has the lowest species diversity (Figure 3.2)
69
250
211 Species richness
200
166 Margalef's Index 150
Menhinick'
s Index
100 91
86
81
72
48 50 28.95 25.76 14.79 12.38 12.57 9.29 11.42 6.75 0 3.20 2.92 3.82 5.61 4.35 3.22 P. maximum–C. I. cylindrica–P. alba A. mearnsii L. simplex–E. E. curvula–S. F. homblei–B. E. curvula–E. SPECIES RICHNESS AND SPECIES EVENESS VALUES EVENESS SPECIESAND RICHNESS SPECIES erythrophyllum woodland woodland magalismontanum vulgaris grassland africana woodland gummiflua woodland woodland grassland
HABITAT UNITS
Figure 3.1: Species richness, Menhinick’s Index and Margalef’s Index for the seven different habitat units on Telperion
70 250 Shannon Wiener
entropy 202.56
200 RGS(Rich-
Gini-
154.38 Simpson
150 Index)
100
81.90
73.71
70.36
53.04
52.22
DIVERSITY VALUE DIVERSITY
48.24
50 36.48
22.14
21.25
11.83
8.74 7.89 0 P. maximum–C. I. cylindrica–P. alba A. mearnsii L. simplex–E. E. curvula–S. F. homblei–B. E. curvula–E. erythrophyllum woodland woodland magalismontanum vulgaris grassland africana woodland gummiflua woodland woodland grassland
HABITAT UNITS
Figure 3.2: Shannon-Wiener Entrophy and Rich-Gini-Simpson Index of the effective number of species values for the seven different habitat units on Telperion
71 3.2.5 Plant Species Similarity
The measure of species similarity between the seven different habitat units at Telperion have a low similarity of species between the habitat units. The highest species similarity amongst the habitats was between the Loudetia simplex– Englerophytum magalismontanum woodland (habitat unit 4) and the Eragrostis curvula–Eragrostis gummiflua grassland (habitat unit 7). The lowest species similarity was measured between the Acacia mearnsii woodland (habitat unit 2) and the Eragrostis curvula–Stoebe vulgaris grassland (habitat unit 5) as well as between the Fadogia homblei-Burkea africana woodland (habitat unit 6) and the Eragrostis curvula–Stoebe vulgaris grassland (habitat unit 5). The Jaccard Similarity Index between habitats is shown in Table 3.3.
72
Table 3.3: The Jaccard Index values for species similarity between the seven habitat units at Telperion Habitat Habitat unit Habitat unit Habitat unit Habitat unit Habitat unit Habitat unit unit 1 2 3 4 5 6 7 Panicum maximum–Combretum erythrophyllum woodland (habitat unit 1) ------
Imperata cylindrica–Populus alba woodland (habitat unit 2) 0.27 ------
Acacia mearnsii woodland (habitat unit 3) 0.14 0.09 - - - - -
Loudetia simplex–Englerophytum magalismontanum woodland (habitat unit 0.14 0.14 0.14 - - - - 4) Eragrostis curvula–Stoebe vulgaris grassland (habitat unit 5) 0.25 0.29 0.06 0.25 - - -
Fadogia homblei–Burkea africana woodland (habitat unit 6) 0.23 0.19 0.07 0.26 0.35 - -
Eragrostis curvula–Eragrostis gummiflua grassland (habitat unit 7) 0.17 0.20 0.11 0.39 0.33 0.30 -
73
3.3 DISCUSSION
A total of 355 plant species were identified in the seven habitat units combined. The plants recorded in the habitat units consisted out of 65 woody plants made up of trees and shrubs, 80 grass species and 237 forbs and geophytes. Thirty-two alien and exotic plants were recorded which includes woody and herbaceous alien plants and some naturalised exotic species. Plants recorded are shown in Annexure A.
3.3.1 Habitat types
The Panicum maximum–Combretum erythrophyllum woodland (habitat unit 1) is located along the river systems of Teleprion, whilst the Imperata cylindrica–Populus alba woodland (habitat unit 2) is located in wetlands and along perennial streams. The hydrology, soil and slope of these two habitats are similar. Both have a perennially flowing stream network with a floodplain and a well-established grass sward. The vegetation structure between the Panicum maximum-Combretum erythrophyllum woodland (habitat unit 1) and the Imperata cylindrica–Populus alba woodland (habitat unit 2) differ significantly especially with reference to the woody layer. The tree Combretum erythrophyllum is dominant within the Panicum maximum-Combretum erythrophyllum woodland (habitat unit 1) and grows along a protected and defined riparian zone with a spreading canopy and drooping branches. The woody layer has a distinct browse-line and the area is utilised by animals for various purposes (for example feeding, drinking and burrows). Trees have a density of 231 ind/ha and the shrub densities are 386 ind/ha. The tree canopy volume is 15754,2 m3 per hectare and that of the shrub layer is 1351 m3 per hectare. The mean height of the tree layer is 5.3 m and the shrubs are 1.5 m.
The Imperata cylindrica–Populus alba woodland (habitat unit 2) is located in wetlands and along perennial streams. This woodland habitat developed as a result of anthropogenic influences and the alien invasive tree Populus alba was planted by people in the past. Populus alba has an upright growth form and has modified the wetland habitat into areas with dense woodland thickets and thick impenetrable
74 lattice-like undergrowth where most of the indigenous species that occurred in the area naturally have been displaced. The trees and shrubs grow close together and there is no indication of the woody layer being utilised by large animals whilst the open grassland areas are used for grazing and drinking. This woodland has a tree density of 891 ind/ha and shrub density of 1584 ind/ha. The total tree canopy volume is 72438.3 m3 per hectare and that of the shrub layer is 2439.36 m3 per hectare. The mean height of the tree layer is 11.6 m and that of the shrubs 1.3 m.
The Acacia mearnsii woodland (habitat unit 3) is also an alien habitat that occurs scattered in smaller patches on Telperion. Compared to other alien plants on Telperion, the Acacia mearnsii community grows in most environments on Telperion. The herbaceous layer underneath Acacia mearnsii is sparse and mostly consists of alien forbs such as Bidens pilosa and Tagetes minuta. The soils are exposed with signs of slight sheet erosion in some areas. The growth form of the trees in this habitat is tall and uneven with no signs of browsing as there was no visible browse line. The clearing of the A. mearnsii trees has resulted in large numbers of the cut stumps to coppice which creates a dense shrub layer. The trees have a density of 650 ind/ha and shrubs 1500 ind/ha. Although the shrub layer has a lower density compared to the shrub layer of the Imperata cylindrica–Populus alba woodland (habitat unit 2), the canopy volume is four times higher (trees: 50765 m3 per hectare, shrubs: 10650 m3 per hectare). The mean tree height recorded was 6.4 m and that of the shrubs 1.4 m. A section of twelve hectares of this woodland located in open grassland on sandy soil was cleared extensively as part of the alien plant eradication management programme on Teleprion. An accidental fire moved through the Acacia mearnsii woodland (habitat unit 3) and removed most of the grasses in and around the woodland as well as the brush and branches that were left after the vegetation clearing. The grasses that sprouted after the fire was heavily grazed by herbivores while the Acacia mearnsii stumps coppiced and formed a dense shrub layer. Large bare patches of soil resulted, while the forb layer consisted of small scattered patches of the low growing Phyllanthus parvulus, the robust Fadogia homblei and Bulbostylis burchellii. The sparse grass layer comprised of the pioneer grasses Aristida congesta subsp congesta and Cynodon dactylon. Before the fire, the plant community had a well-developed grass layer that surrounded the large woodland.
75 The Loudetia simplex–Englerophytum magalismontanum woodland (habitat unit 4) is located on steep north and south facing slopes with shallow rocky loamy soil. The herbaceous layer varies from sparse to dense stands of the grass Loudetia simplex while the erect forb Salacia rehmannii grow in dense linear patches along the lower ridges where this habitat unit borders open grassland. The woody layer consists of medium to large Croton gratissimus trees and small to medium Englerophytum magalismontanum shrubs. Croton gratissimus and Diplorhynchus condylocarpon are prominent on the northern slopes and Protea caffra and Heteropyxis natalensis shrubs on the south facing slopes of this habitat. On the flatter slightly elevated ridges Strychnos pungens trees are widespread with the scandent shrub Searsia magalismontanum on the exposed rock beds. This woodland is utilised by larger herbivores for grazing and browsing and is also used as shelter by smaller herbivores such as Rock Hyraxes (Procavia capensis) and Jameson Rock Rabbits (Pronolagus randensis). The area is rocky with mild to steep slopes and shallow loamy soil. The trees have a density of 644 ind/ha and the shrubs 1254 ind/ha. The mean tree canopy volume is 37996 m3 per hectare and the mean shrub canopy volume of 1379.4 m3 per hectare. The mean tree height is 4.9 m and the mean shrub layer is 1 m high.
The Eragrostis curvula–Stoebe vulgaris grassland (habitat unit 5) was previously used as cultivated fields due to their deep sandy soil. After cultivation was ceased and the area incorporated into Telperion it developed as a grassland dominated by secondary successional species. This grassland is characterised by the dwarf shrub Stoebe vulgaris that has a density of 957 ind/ha. The mean height of the shrub layer is 0.7 m with a canopy volume of 861.3 m3 per hectare.
The Fadogia homblei–Burkea africana woodland (habitat unit 6) occurs mostly on level terrain with deep sandy soil. The forb Fadogia homblei forms dense patches on drier sections of this habitat, while Pteridium aquilinum is dominant where the soil has a slightly higher moisture content. This woodland habitat also has a large number of woody species that include the tree Burkea africana and the shrubs Ochna pulchra and Euclea crispa. The shrubs vary in height and occur at different densities underneath the tall Burkea africana trees, but is well spaced and does not form dense thickets. In some areas, Burkea africana shrubs of less than 1.5 m form
76 dense thickets with a resultant high canopy cover in the lower layer. This woodland has a tree density of 214 ind/ha and a shrub density of 1036 ind/ha. The mean tree canopy 28547.6 m3 per hectare and the mean shrub canopy volume is 1766.3 m3 per hectare. The mean tree height is 8.3 m and the mean shrub height is 1.1 m. Soil samples taken in this woodland have shown that the sandy soils are deeper than one meter and remain moist, even in the dry season (Pers. obs.). This can probably be ascribed to the dense herbaceous cover promoting water infiltration and the numerous drainage lines where Pteridium aquilinum is dominant. This species can also impede the establishment of tree and other species (Den Ouden, 2000). Plant cover protects soils from erosion by reducing water runoff and promotes greater water infiltration into the soils (Zuazo & Pleguezuelo, 2008) which is the case underneath the dense Pteridium aquilinum plants. The Fadogia homblei–Burkea africana woodland (habitat unit 6) is utilised by herbivores for grazing while numerous burrows of small mammals were observed in the deep sandy soil.
The Eragrostis curvula–Eragrostis gummiflua grassland (habitat unit 7) has not previously been ploughed and consists of shallow loamy rocky soil. In places where the bedrock is exposed small Gymnosporia buxifolia shrubs cover the area. This spiny shrub provides protection for robust grasses such as Diheteropogon amplectens and Themeda triandra to grow without being grazed. Long tillers with hanging inflorescences grow underneath the shrubby clumps from where their seeds are dispersed. The grass layer has a high cover and is heavily grazed by herbivores. Sections, where overgrazing has occurred, have become dominated by the forbs Fadogia homblei and Salacia rehmannii and are especially prominent in the dry season when the grass sward becomes less dense. The woody structure comprises low growing shrubs with few tall trees. This grassland has a shrub density of 66 ind/ha. The mean shrub layer canopy volume is 26.4 m3 per hectare with a mean height of 0.7 m.
The Eragrostis curvula–Stoebe vulgaris grassland (habitat unit 5) and the Eragrostis curvula–Eragrostis gummiflua grassland (habitat unit 7) differ largely in terms of soil depth, texture and species composition even though both are grasslands.
77 The two alien woodland habitats at Telperion are the Imperata cylindrica-Populus alba woodland (habitat unit 2) and the Acacia mearnsii woodland (habitat unit 3). These two habitats can be distinguished from each other not only by species composition but also by their differences in densities and canopy volumes. The shrub layer of the Acacia mearnsii woodland (habitat unit 3) has a lower density compared to the shrub layer of the Imperata cylindrica–Populus alba woodland (habitat unit 2). The Acacia mearnsii trees and shrubs that have a robust growth form with the tree and shrub canopies growing close to one another whereas the Populus alba trees and shrubs of the Imperata cylindrica-Populus alba woodland (habitat unit 2) have a slender and upright growth form. As a result, the canopy volume of the Acacia mearnsii woodland (habitat unit 3) is four times higher than that of the Imperata cylindrica–Populus alba woodland (habitat unit 2).
The Loudetia simplex–Englerophytum magalismontana woodland (habitat unit 4) and the Fadogia homblei–Burkea africana woodland (habitat unit 6) consist of well- developed woody layers with medium to large trees and shrubs. The herbaceous layer is well developed and heavily grazed resulting in the establishment of numerous forbs. The dominant forbs in both habitats are Fadogia homblei and Salacia rehmannii that grows in dense clumps. Fadogia homblei grows in patches together with tall to medium-tall grasses such as Trachypogon spicatus, Themeda triandra and Diheteropogon amplectens. The grasses are inaccessible because of the dense and spiny shrubs and not utilised by herbivores and long tillers grow upward through the forb canopy. The forb Salacia rehmannii grows more upright at steeper rocky areas of the Loudetia simplex–Englerophytum magalismontana woodland (habitat unit 4) and form dense linear strips with fewer grasses protruding from underneath.
The Loudetia simplex–Englerophytum magalismontanum woodland (habitat unit 4) differs in topography, vegetation structure and soil type from the Fadogia homblei– Burkea africana woodland (habitat unit 6). The Fadogia homblei–Burkea africana woodland (habitat unit 6) grows on slight to flat slopes and the soils are deeper and less rocky in most areas compared to that of the Loudetia simplex–Englerophytum magalismontanum woodland (habitat unit 4).
78 The tree layer of the Loudetia simplex–Englerophytum magalismontanum woodland (habitat unit 4) has a higher density than the Fadogia homblei–Burkea africana woodland (habitat unit 6) but the mean height of the trees of the Loudetia simplex– Englerophytum magalismontanum woodland (habitat unit 4) is lower. The tree layer in the Fadogia homblei-Burkea africana woodland (habitat unit 6) grows in a uniform upright manner and has a distinct trunk with almost no leaf cover from the base of the tree and below the canopy. The canopy of tree species in the Loudetia simplex- Englerophytum magalismontanum woodland (habitat unit 4) is robust with trailing and upright branches and the first leaves grow at different heights. The Fadogia homblei–Burkea africana woodland (habitat unit 6) has taller woody vegetation with flat spread out tree canopies that in some areas connects with another tree canopy albeit that the actual trees are rooted far from the other. The height of the shrub layer between the Loudetia simplex–Englerophytum magalismontanum woodland (habitat unit 4) and the Fadogia homblei–Burkea africana woodland (habitat unit 6) varies little but the shrub density is higher in Loudetia simplex–Englerophytum magalismontanum woodland (habitat unit 4). The Fadogia homblei-Burkea africana woodland (habitat unit 6) shrub layer is made up of short bulky shrubs with the height of the first leaves touching the ground surface whereas the Loudetia simplex- Englerophytum magalismontanum woodland (habitat unit 4) shrubs have a distinct browse line and the height of the first leaves rarely touches the ground surface
3.3.2 Species richness & diversity
The Loudetia simplex-Englerophytum magalismontanum woodland (habitat unit 4) has the highest species richness and species diversity of all the habitats (figures 3.1 & 3.2). This high diversity can be ascribed to the various microhabitats found within this rocky woodland habitat. Rocky areas in the Bankenveld have been found to have a high diversity (Bredenkamp & Brown 2003). Brown and Bezuidenhout (2018) have also found the rocky areas within the Nama-karoo to have a higher diversity than the surrounding grassland vegetation.
The Eragrostis curvula-Eragrostis gummiflua grassland (habitat unit 7) has a similar diversity than the Loudetia simplex-Englerophytum magalismontanum woodland (habitat unit 4) (figure 3.2) but in comparison the Eragrostis curvula-Eragrostis
79 gummiflua grassland (habitat unit 7) has lower species richness than the Loudetia simplex-Englerophytum magalismontanum woodland (habitat unit 4) (figure 3.1). Natural grasslands are regarded as species-rich with high diversity (Cadman, 2013). The Eragrostis curvula-Eragrostis gummiflua grassland (habitat unit 7) is fairly undisturbed which explains its high diversity. The Eragrostis curvula-Stoebe vulgaris grassland (habitat unit 5) is previously disturbed grassland but has the third highest species diversity and species richness of all the habitats. When this previously disturbed grassland is compared to the natural Eragrostis curvula-Eragrostis gummiflua grassland (habitat unit 7), the disturbed grassland contained 46% less in species richness whilst it also has a large number of pioneer and secondary successional species.
Species richness and biodiversity differ largely between the Loudetia simplex– Englerophytum magalismontana woodland (habitat unit 4) and the Fadogia homblei– Burkea africana woodland (habitat unit 6). The Fadogia homblei–Burkea africana woodland’s (habitat unit 6) has the second lowest species richness as well as the second lowest species diversity of all the habitats compared to the Loudetia simplex–Englerophytum magalismontana woodland (habitat unit 4), which has the highest species richness and the highest species diversity of all the habitats. The low species diversity of the Fadogia homblei–Burkea africana woodland (habitat unit 6) could be the result of its higher species homogeneity in the woody layer compared to the heterogeneous woody layer and the forb rich herbaceous layer of the Loudetia simplex–Englerophytum magalismontana woodland (habitat unit 4).
The two alien plant habitats Imperata cylindrica-Populus alba woodland (habitat unit 2) and the Acacia mearnsii woodland (habitat unit 3) have a low species richness and species diversity. The alien vegetation in the two habitats dominates the vegetation and reduced the indigenous plant species. Alien plant invasion is a common cause of the loss of indigenous species richness (Nijs et al., 2012) and explains the low species richness and species diversity of the Imperata cylindrica- Populus alba woodland (habitat unit 2) and the Acacia mearnsii woodland (habitat unit 3).
80 The invasion of alien and invasive plants into previously natural areas, such as the Imperata cylindrica-Populus alba woodland (habitat unit 2) and the Acacia mearnsii woodland (habitat unit 3), have created significant changes to the area often having negative effects on animals and indigenous vegetation and the food resources that animals depend on (Clusella–Trullas & Garcia, 2017). Acacia mearnsii has been found to have a neutral to negative effect on arthropods and invertebrates (Clusella– Trullas & Garcia, 2017). These areas do however also create new habitats for other animal species and could provide habitat for chameleons.
3.4 CONCLUSION
A total of seven habitat units were identified and described in this study and all are thought to have some suitability for chameleons in terms of perch plants and potential nesting sites. The seven identified habitat units differed floristically and in terms of structure and height. The different habitats identified can broadly be grouped into the following groups: riverine woodland (Panicum maximum- Combretum erythrophyllum woodland, habitat unit 1), alien woodlands (Imperata cylindrica-Populus alba woodland, habitat unit 2 and Acacia mearnsii woodland habitat unit 3), rocky woodlands (Loudetia simplex-Englerophytum magalismontanum woodland, habitat unit 4 and Fadogia homblei-Burkea africana woodland, habitat unit 6) and grasslands (Eragrostis curvula-Stoebe vulgaris grassland, habitat unit. 5 and Eragrostis curvula-Eragrostis gummiflua grassland, habitat unit 7).
The Eragrostis curvula–Stoebe vulgaris grassland (habitat unit 5) and the Eragrostis curvula–Eragrostis gummiflua grassland (habitat unit 7) are similar in appearance and structure. They do however differ in terms of dominant species, successional stage and previous utilisation. Stoebe vulgaris is dominant in the Eragrostis curvula- Stoebe vulgaris grassland (habitat unit 5) which has deep soil and was previously used for cultivation. This grassland is in a secondary successional phase and dominated by secondary plant species. In contrast, the Eragrostis curvula-Eragrostis gummiflua grassland (habitat unit 7) occurs in shallow soil and is less degraded and has not previously been used for cultivation. The Eragrostis curvula-Eragrostis
81 gummiflua grassland (habitat unit 7) comprises a mixture of climax and secondary successional species and is regarded as a more resilient habitat.
The species richness and diversity of the habitat types may contribute positively to the amount of food available to the Common Flap-Necked chameleon (Chamaeleo dilepis) on Telperion. C. dilepis is known to forage mainly on insects (Brian, 1961; Wager, 1983; Le Berre, 2009; Tolley & Herrel, 2014) and a diverse vegetation composition would allow for niches for insects to reside in and therefore the area will have more insect species available in the specific area (Smith et al., 2010). The species richness and species diversity within the habitats at Telperion differ because of natural and anthropogenic influences and it may impact resources that C. dilepis depend on for its survival. The abundance or shortage of resources or the suitability of microclimatic variables for its survival could determine if C. dilepis will occupy the available habitats or not.
There are many habitat factors that contribute to the presence and absence of the Common Flap-Necked chameleon (Chamaeleo dilepis) in a habitat. The floristic composition and structure play an important role in providing habitat resources to different animal species and therefore plants and animals may be found together in an area because their resource needs may be similar (Van As et al, 2012). Required resources include food availability within plant habitats and/or varying microhabitat conditions, changes in soil humidity (Dimaki et al., 2015) and a difference in reproductive success such as finding a mate and nest construction (Martin, 1992). Abiotic resources such as soil texture type, moisture, thermoregulation and shelter may be just as important to the survival of C. dilepis as the requirements of the biotic resources required by C. dilepis to survive. According to Smith (1977), an organism’s habitat selection may be directly related to food availabilityand the selection of habitat by prey may be directly influenced by the structural features of that habitat. Structural features of habitat are mostly made up of the plant species available in such a habitat (Smith, 1977). The availability of food in the form of insects and arthropods such as grasshoppers and crickets that C. dilepis primarily feeds on (Tolley & Burger, 2007), may cause C. dilepis to utilise or not utilise certain habitats. Arthropod diversity within grasslands is often connected to the plant species composition and the habitat structure (Latchininsky et al., 2011) but in habitats
82 containing a tree or shrub layer arthropod species abundances can be higher compared with grassland habitats that have simpler structures (Botha et al., 2016). Plant species richness and plant biodiversity within habitats available to C. dilepis at Telperion may influence the prey availability because insect diversity is significantly higher in plant communities rich in botanical species (De Cauwer et al., 2006). The information generated from this chapter will be used to explain and interpret the distribution and use of the various habitats by the flap-necked chameleon on Telperion.
Chameleon habitat comprises of vegetation structures that include open-canopy habitats such as savanna, grassland and woodland and closed-canopy habitats such as forests (Tolley & Herrel, 2014). While the majority of chameleons have been found to inhabit closed-canopy habitats such as forests, the genus Chamaeleo has species that occupy both open and closed-canopy habitats (Tolley & Herrel, 2014). From the findings of this chapter, the habitats available to chameleons on Telperion include open-canopy habitats made up of natural grassland, rocky woodland, open woodland, riparian habitat and alien woodlands. Chameleons are mostly arboreal (Tolley & Herrel, 2014) and only a few chameleon species are found in the grassland biome, usually in the vicinity of the boundary where the grassland biome meets another biome (Tolley & Burger, 2007) such as forest or savanna. Species known to have been found to utilise grassland habitats are the Drakensberg Dwarf Chameleon (Bradypodion dracomontanum), Eastern Cape Dwarf Chameleon (Bradypodion ventrale) and the Kentani Dwarf Chameleon (Bradypodion kentanicum) (Tolley & Burger, 2007). Tolley and Burger (2007) state that C. dilepis is found in different habitats such as coastal forest, woodland thicket and savanna and makes no mention of grasslands as a habitat. C. dilepis may choose different habitats in terms of food availability, shelter and reproduction. The most suitable habitat for C. dilepis may differ during its life cycle, therefore, adults may prefer woodland habitats because of the chameleon’s arboreal habits, whereas juvenile chameleons have been found perching mostly on grasses (Tolley & Herrel, 2014) and during the first part of their life cycles C. dilepis may prefer grassland habitats.
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87 CHAPTER 4 - CHAMELEON ECOLOGY ON TELPERION
4.1 INTRODUCTION
The understanding of chameleon ecology is generally lacking (Tolley & Herrel, 2014) and in most protected areas there is little formal information for chameleons to include into reserve management plans. Globally, chameleon species are decreasing annually due to human-induced habitat degradation (Carpenter et al., 2004). Due to the lack of understanding of chameleon distribution, factors that influence or threaten their survival as well as population dynamics, implementation of suitable conservation strategies are difficult (Tolley & Herrel, 2014). Although conservation planning is related to most species within conservation areas such as national parks, provincial nature reserves and private game reserves in South Africa, these plans do not readily take reptile conservation into account. Due to the rapid rate of urbanisation and the development of natural habitats these parks and nature reserves may be some of the last refuges for chameleon species. Forty-seven open habitat chameleon species have been identified and therefore in areas where these open habitats are extensive, these species are considered to be wide-ranging (Tolley & Herrel, 2014). The largest distribution of open habitat chameleons is in savanna areas (Tolley & Herrel, 2014) which are also adjacent to the grassland areas in South Africa (Mucina & Rutherford, 2006). As savannas represent 32.8% of the South African vegetation these areas within South Africa are potentially important for the conservation of chameleons. C. dilepis is associated with open habitat such as woodland savannas and grasslands (Tolley & Herrel, 2014) therefore this study of C. dilepis on Telperion provides a good basis to obtain knowledge of the ecology of a common chameleon species within the grassland biome.
The aim of this chapter was to investigate the ecology of Chamaeleo dilepis on Telperion.
88 4.2 RESULTS
4.2.1 Morphological measurements of C. dilepis
During the study period (July 2016 to July 2017), 112 C. dilepis individuals were observed during surveys. Of these 112 only 66 individuals were weighed and measured, due to various physical and climatic factors. For example, chameleons were sometimes perched too high up in the vegetation to be safely reached, handled, or if the ambient temperature during the survey was <10oC perching chameleons tended to be very lethargic and were observed to struggle to perch after handling. In some cases, hatchlings were too fragile to handle and some showed signs of stress by either showing a spotted pattern on the skin or turning black in colour.
Of the 66 individuals measured and weighed, 21 were hatchlings (3 males and 18 females), 26 were sub-adults (7 males and 19 females) and 19 were adults (11 males and 8 females).
Data for hatchlings, sub-adults and all age classes combined were not normally distributed and therefore the Mann-Whitney U-test was used to determine if there were statistical differences between males and females in these age classes. The data recorded for the adult age class was normally distributed and a t-Test for unmatched pairs was used to analyse this data.
Measurement differences of hatchlings and sub-adults were not significant. Significant differences between adult males and adult females for SVL (t = 6.807, p = 0.00001, df 17), STL (t = 4.354, p = 0.0004, df 17) and mass (t =8.786, p = 0.00001, df 17) were found, with adult females being significantly larger and heavier than males. The Mann-Whitney U-test for all age classes combined showed a statistical difference between male and female SVL (U= 321, p= 0.028) STL (U= 282.5, p= 0.009) and mass (U= 325, p= 0.043). Results of the morphological measurements and associated statistical analysis are presented in Table 4.1.
89 Both the SVL and STL were higher for males, but females generally weighed more than males when all age classes were combined.
90 Table 4.1: Morphological analysis between the different age classes of male and female C. dilepis (*statistical significance at the 95% confidence level)
Male Female Statistical result at α= 0.05 Sample Age class Mean ±SD Range Mean ±SD Range U a T b p Hatchling 3.33 ± 0.47 3 - 4 (n=3) 4.61 ± 1.03 3 - 7 (n=18) 8 - 0.062 Mass Sub-adult 5 ± 1 4 - 7 (n=18) 5.868 ± 2.69 3 - 12 (n=19) 65 - 0.952 (g) Adult 18.045 ± 6.158 10 - 30 (n=11) 49.375 ± 9.425 35 - 65 (n= 8) - 8.786 <0.00001* All Age classes 11.76 ± 8.05 3 - 30 (n - 21) 12.78 ±17.74 3 - 65 (n= 45) 325 - 0.043 Hatchling 31.66 ± 2.35 30 - 35 (n=3) 51.14 ± 30.88 25 - 40 (n = 18) 18 - 0.412 SVL Sub-adult 46.42 ± 6.90 40 - 55 (n=18) 48.94 ± 8.90 40 - 65 (n= 19) 56 - 0.562 (mm) Adult 79.090 ± 10.202 60 - 90 (n=11) 115 ± 12.817 100 - 130 (n=8) - 6.807 <0.00001* All Age classes 61.42 ± 21.22 30 - 90 (n= 21) 33.33 ± 3.83 25 - 130 (n = 45) 321 - 0.028* Hatchling 66.66 ± 2.35 65 - 70 (n=3) 66.11 ± 6.31 50 - 70 (n= 18) 23 - 0.740 Sub-adult 88.57 ± 10.29 80 - 105 (n=18) 95.78 ± 19.59 75 - 150 (n=19) 56 - 0.562 STL (mm) Adult 159.545 ± 17.529 130 - 180 (n= 11) 213.125 ± 35.550 160 - 260 (n =8) - 4.354 0.0004* 282. All Age classes 122.62 ± 42.56 65 - 180 (n= 21) 92.96 ± 59.74 50 - 260 (n=45) - 0.009* 5 Hatchling 1.18 ± 0.90 0.5 - 2 (n=3) 0.85 ± 0.98 0.21 - 4.6 ( n=18) 42.5 - 0.125 Perch Sub-adult 0.64 ± 0.79 0.1 - 2.4 (n=18) 1.32 ± 1.71 0.3 - 8 (n=19) 35.5 - 0.078 height Adult 1.518 ± 0.904 0.3 - 2.8 (n = 11) 1.738 ± 0.772 0.4 - 3 (n= 8 ) - 0.556 0.585 (m) 462. All Age classes 1.18 ± 0.60 0.1 – 2.8 (n= 21) 1.21 ± 1.33 0.21 - 8 (n= 45) - 0.089 5 a Data is not distributed normally b Data is normally distributed
91 Although the height perched between sexes and/or age classes did not show statistically significant differences there were biological differences in mean heights observed between sexes of the hatchlings and sub-adults. Male hatchlings had a perch range of 0.5 - 2 m (n=3) in height and females had a range of 0.21 - 4.6 m (n=18). Sub-adult males had a mean perch range of 0.1 - 2.4 m (n=18) compared to sub-adult females that had a perch range of 0.3 – 8 m (n=19). The differences in the perch height of adult males and females were similar in range Perch heights varied monthly during the study period and perching by adult males and females were lower in November 2016 but increased in height toward April 2017. Perch heights were lower again toward May 2017 (Figure 4.1).
9
8 Adult Male
7 Adult Female 6
5
4
3
2 Mean Height perched (m) perched Height Mean 1
0 Nov-16 Dec-16 Jan-17 Feb-17 Mar-17 Apr-17 May-17 -1
Figure 4.1: Mean perch heights of adult male and female C. dilepis during the study period on Telperion
92 4.2.2 Habitat utilisation
Seven habitat units were potentially available to chameleons within the study area on Telperion (Refer to chapter 3). Results of the generated Bonferroni confidence intervals indicated that the utilization of habitat units by C dilepis were not in proportion to the availability of these habitat units within the study area on Telperion (Table 4.2).
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Table 4.2: Occurrence of C. dilepis in the seven different habitats compared to habitat availability within the study area Expected No of Proportion C. dilepis proportion of Confidence interval on Age Size Proportion of Expected no of C. Habitat Unit a chameleons b observed in each C. dilepis in proportion of occurrence (Pii) Class (Ha) total ha (Pi0) dilepis c d observed habitat unit (Pi) each habitat (95% confidence) unit
1. Panicum maximum–Combretum erythrophyllum woodland 74 0.013 14 2 0.125 0.013 0.041 ≤ p1 ≤ 0.209 2. Imperata cylindrica–Populus alba woodland 100.6 0.018 0 2 0 0.018 0.000 ≤ p ≤ 0.000 3. Acacia mearnsii woodland 24 0.004 23 0 0.205 0.004 0.103 ≤ p3 ≤ 0.308 4. Loudetia simplex–Englerophytum magalismontanum woodland 2631.2 0.480 32 54 0.286 0.480 0.171 ≤ p ≤ 0.401 5. Eragrostis curvula–Stoebe vulgaris grassland 1121.2 0.204 4 23 0.036 0.204 -0.011 ≤ p ≤ 0.083 6. Fadogia homblei–Burkea africana woodland 239.9 0.044 37 5 0.330 0.044 0.211 ≤ p6 ≤ 0.450 7. Eragrostis curvula–Eragrostis gummiflua grassland 1295.2 0.236 2 26 0.018 0.236 -0.016 ≤ p7≤ 0.052
Combined age classes Total 5486 112
1. Panicum maximum–Combretum erythrophyllum woodland 74 0.013 7 1 0.104 0.013 0.004 ≤ p1 ≤ 0.205 2. Imperata cylindrica–Populus alba woodland 100.6 0.018 0 1 0 0.018 -
3. Acacia mearnsii woodland 24 0.004 18 0 0.269 0.004 0.123 ≤ p ≤ 0.414 4. Loudetia simplex–Englerophytum magalismontanum woodland 2631.2 0.480 5 32 0.075 0.480 -0.012 ≤ p3 ≤ 0.161 5. Eragrostis curvula–Stoebe vulgaris grassland 1121.2 0.204 5 14 0.075 0.204 -0.012 ≤ p ≤ 0.161
Hatchlings 6. Fadogia homblei–Burkea africana woodland 239.9 0.044 32 3 0.478 0.044 0.313 ≤ p ≤ 0.642 7. Eragrostis curvula–Eragrostis gummiflua grassland 1295.2 0.236 0 16 0 0.236 - Total 5486 67
1. Panicum maximum–Combretum erythrophyllum woodland 74 0.013 3 0 0.143 0.013 0.028 ≤ p1 ≤ 0.258
2. Imperata cylindrica–Populus alba woodland 100.6 0.018 0 0 0 0.018 -
s 3. Acacia mearnsii woodland 24 0.004 1 0 0.048 0.004 -0.022 ≤ p ≤ 0.118
4. Loudetia simplex–Englerophytum magalismontanum woodland 2631.2 0.480 17 10 0.810 0.480 0.680 ≤ p3 ≤ 0.939 adult - 5. Eragrostis curvula–Stoebe vulgaris grassland 1121.2 0.204 0 4 0 0.204 -
Sub 6. Fadogia homblei–Burkea africana woodland 239.9 0.044 0 1 0 0.044 - 7. Eragrostis curvula–Eragrostis gummiflua grassland 1295.2 0.236 0 5 0 0 - Total 5486 21
1. Panicum maximum–Combretum erythrophyllum woodland 74 0.013 4 0 0.167 0.013 0.044 ≤ p1 ≤ 0.289 2. Imperata cylindrica–Populus alba woodland 100.6 0.018 0 0 0 0.018 -
3. Acacia mearnsii woodland 24 0.004 1 0 0.042 0.004 -0.024 ≤ p ≤ 0.107
4. Loudetia simplex–Englerophytum magalismontanum woodland 2631.2 0.480 13 12 0.542 0.480 0.378 ≤ p3 ≤ 0.705
5. Eragrostis curvula–Stoebe vulgaris grassland 1121.2 0.204 0 5 0 0.204 - Adults 6. Fadogia homblei–Burkea africana woodland 239.9 0.044 5 1 0.208 0.044 0.075 ≤ p ≤ 0.342 7. Eragrostis curvula–Eragrostis gummiflua grassland 1295.2 0.236 1 6 0.042 0.236 -0.024 ≤ p ≤ 0.107 Total 5486 24 a Proportion of total hectares represents the expected C. dilepis observation values as if C. dilepis occurred in each habitat unit in exact proportion to availability, b Calculated by multiplying proportion Pi0 x n, n number of C. dilepis observed in a habitat unit divided by the total observations of C. dilepis, d Pii represents the theoretical proportion of occurrence and is compared to corresponding Pi0 to determine if the hypothesis of proportional use is accepted or rejected, i.e., Pii = Pi0
94 Ages of chameleons showed a shift in habitat unit utilisation over time. Combined observations of all age classes were also statistically analysed to prevent the data from being skewed by the presence of large numbers of hatchlings and sub-adults.
Analysis of the combined age classes (n=112) indicated that C. dilepis utilised the Panicum maximum–Combretum erythrophyllum woodland (habitat unit 1), Acacia mearnsii woodland (habitat unit 3) and the Fadogia homblei–Burkea africana woodland (habitat unit 6) more than expected in proportion to the habitat’s availability. In contrast, the Englerophytum magalismontanum-Loudetia simplex grassland (habitat unit 4), Eragrostis curvula–Stoebe vulgaris grassland (habitat unit 5) and the Eragrostis curvula- Eragrostis gummiflua grassland (habitat unit 7) were utilized less than expected. No observations of chameleons were made in the Imperata cylindrica–Populus alba woodland (habitat unit 2).
Hatchlings (n=67) utilised the Acacia mearnsii woodland (habitat unit 3) and the Fadogia homblei–Burkea africana woodland (habitat unit 6) more than expected, whereas the Panicum maximum-Combretum erythrophyllum woodland (habitat unit 1), Loudetia simplex–Englerophytum magalismontanum woodland (habitat unit 4) and the Eragrostis curvula–Stoebe vulgaris grassland (habitat unit 5) were utilised less than expected. No hatchlings were observed within the Imperata cylindrica– Populus alba woodland (habitat unit 2) or Eragrostis curvula-Eragrostis gummiflua grassland (habitat unit 7). Sub-adults (n=21) utilised the Panicum maximum– Combretum erythrophyllum woodland (habitat unit 1), Acacia mearnsii woodland (habitat unit 3) and the Loudetia simplex–Englerophytum magalismontanum woodland (habitat unit 4) more than expected. No sub–adults were observed within the remaining habitat units. Adults (n=24) utilised the Panicum maximum– Combretum erythrophyllum woodland (habitat unit 1), the Acacia mearnsii woodland (habitat unit 3) and the Fadogia homblei-Burkea africana woodland (habitat unit 6) more than expected. The Loudetia simplex–Englerophytum magalismontanum woodland (habitat unit 4) and Eragrostis curvula-Eragrostis gummiflua grassland (habitat unit 7) was used significantly less than expected by adults and no adults were observed in the Imperata cylindrica–Populus alba woodland (habitat unit 2) or in the Eragrostis curvula–Stoebe vulgaris grassland (habitat unit 5).
95
4.2.3 Seasonality
The study period (July 2016–July 2017) included a wet and a dry season (Mucina & Rutherford, 2006). The dry season was considered to be from the beginning of May to the end of September and the wet season from the beginning of October to the end of April. No C. dilepis were found at the start of the study in July 2016 to the end of October 2016 or from the beginning of June 2017 to the end of the study period at the end of July 2017. C. dilepis were only found after the first rainfall event in October 2016 and were then present during the remainder of the wet season. The first C. dilepis individuals that were found during November 2016 after the first rainfall were adults and hatchlings. These C. dilepis individuals were only found from January 2017. When mean temperatures dropped below 14 ˚C and no more rainfall was recorded around the end of May 2017, no chameleons were located for the remainder of the study period (until the end of July 2017). Temperatures and rainfall recorded by the Clima-stats temperature loggers and rainfall meter readings on Telperion and the observations of C. dilepis during the study period are shown in figure 4.2.
180 Number of adults 160 Number of sub - adults 140 Number of hatchlings 120 Rainfall (mm) 100 Min Temp ˚C Max Temp ˚C 80 Ave Temp ˚C 60 40 20 0
-20
Jul-16 Jul-17
Oct-16 Apr-17
Jan-17 Jun-17
Feb-17 Mar-17
Nov-16 Dec-16
Aug-16 Sep-16 May-17 Figure 4.2: The number of C. dilepis per age class in relation to temperature and rainfall on Telperion during the study period.
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The General Additive Model (GAM) used to determine if there were associations between temperature, photoperiod, rainfall and the recorded occurrences of C. dilepis suggested that rainfall significantly influences the occurrence of hatchlings (P =0.094) (Table 4.3) at 90% level of confidence, whereas the minimum temperature is suggested to have a significant influence on the occurrence of adults (P =0.037) and sub-adults (P =0.032), at a 95% confidence level (Table 4.3).
Table 4.3: The General Additive Model (GAM) Statistic for the association of climatic variables and the occurrence of various age classes of C. dilepis (*statically significant) Hatchlings at 90% level of confidence Variable Estimate Std Error t-value Pr (>ItI) Rainfall 0.197 0.102 1.930 0.094* Min Temperature -2.282 1.630 -1.400 0.204 Max Temperature -1.563 2.096 -0.746 0.480 Mean Temperature 2.295 3.418 0.671 0.523 Photoperiod 6.790 9.073 0.748 0.478 Sub-adults at 95% level of confidence Variable Estimate Std Error t-value Pr (>ItI) Rainfall -0.043 0.025 -1.680 0.134 Min Temperature 1.093 0.410 1.693 0.032* Max Temperature 0.709 0.527 2.662 0.222 Mean Temperature -0.709 0.860 -1.339 0.437 Photoperiod -3.758 2.284 -0.824 0.143 Adults at 95% level of confidence Variable Estimate Std Error t-value Pr (>ItI) Rainfall 0.023 0.016 1.435 0.194 Min Temperature 0.664 0.259 2.558 0.037* Max Temperature 0.281 0.334 0.843 0.426 Mean Temperature -0.649 0.544 -1.192 0.272 Photoperiod -0.298 1.446 -0.207 0.842
Seasonality in age classes was evident based on the presence and absence of hatchlings, sub–adult and adult C. dilepis during the study period at different times and within different habitat units. Eggs have early gastrula, development is slow and hatching is seasonal (Tolley & Herrel, 2014). C. dilepis eggs can take up to a year to hatch (Wager, 1983) and in other chameleons, long incubation periods are known to occur especially in species that inhabit seasonal environments (Karsten et al., 2008). Figure 4.3 illustrates the different C. dilepis age classes and their occurrence on Telperion during the study period.
97
Hatchling 48 15 4
Sub-adult 12 5 4
Adult 1 4 4 3 8 2 2
Oct-16 Nov-16 Dec-16 Jan-17 Feb-17 Mar-17 Apr-17 May-17 Jun-17 Jul-17
Figure 4.3: Monthly occurrences with numbers in the bars indicating the monthly observations of the various C. dilepis age classes found on Telperion during the study period
4.2.4 Dispersal of C. dilepis
One nest site was found on the 14th of January 2017 in the Fadogia homblei–Burkea africana woodland (habitat unit 6). This nest was checked for three consecutive nights and then again 12 nights later. Recently emerged hatchlings are identifiable due to their round heads and the lack of neck flaps that are present in older C. dilepis (Tolley & Burger, 2007) as well as sand being stuck to the hatchling’s heads from recently burrowing out of the nest (O’Donoghue, 1 ). During the initial count of hatchlings at the nest site, 18 hatchlings were counted within a 4.28 m2 area surrounding the nest site. All hatchlings were perched on grasses. Over the following two consecutive nights, the dispersal distance of the hatchlings from the nest location increased from a mean distance of 6.17 m (9 hatchlings were counted) to 20.66 m (8 hatchlings counted) respectively. On day 14 the four hatchlings that were found were at a mean distance of 38.9 m from the hatching site. (Figure 4.4).
98
Figure 4.4: Dispersal of hatchlings from a nest site on Telperion recorded over a 14 day period
4.2.5 Perch plant utilisation
C. dilepis on Teleprion made use of 39 plant species as perch sites. In the homogenous low species-rich habitats, such as the Acacia mearnsii woodland (habitat unit 3) and the Fadogia homblei-Burkea africana woodland (habitat unit 6) where the vegetation was dominated by one or two plant species, C. dilepis perched on plant species in relation to the plant species cover-abundance. This may be because no other plant species were available. The vegetation in more heterogeneous and species-rich habitat units such as the Loudetia simplex- Englerophytum magalismontanum woodland (habitat unit 4) where the variety of plant species are higher the perch plant selected as perches was higher and there was no indication that a specific plant species were preferred by C. dilepis. Hatchlings utilised grasses and herbaceous plants more than any other plant structure, whereas sub-adults and adults made use of woody plants more than any
99 other plant structure available to them in the respective habitat units. The results for perches in each of the habitat units is shown in Table 4.4
100
Table 4.4: Plant species that C. dilepis utilised as perches during the study period on Telperion n Bruan- Plant Habitat unit a b c Plant species Blanquet H S A structure cover value 1 - - Brachiaria brizantha Grass r Panicum maximum– 1 - - Combretum erythrophyllum Woody 4 Combretum 1 1 - Diospyros lycioides Woody + erythrophyllum 1 2 4 Searsia pyroides Woody 1 woodland 2 - - Sporobolus africanus Grass 2 1 - - Zinnia peruviana Forb + 7 1 1 Acacia mearnsii Woody 5 1 - - Aristida barbicollis Grass + 1 - - Aristida stipitata Grass r - 1 - Burkea africana Woody + Acacia mearnsii 1 - - Dichapetalum cymosum Forb + woodland 4 - - Eragrostis curvula Grass + 1 - - Fadogia homblei Forb 1 1 - - Gomphocarpus fruticosus Forb r 3 - - Gymnosporia buxifolia Woody 1 1 - - Perotis patens Grass r - 2 2 Burkea africana Woody 2 - - 3 Canthium gilfillanii Woody r - 1 - Combretum molle Woody 2 - 1 - Euclea crispa Woody + - - 1 Faurea saligna Woody r Loudetia simplex– - 1 - Indigofera comosa Shrub r Englerophytum - 2 2 Ochna pulchra Woody r magalismontanum Olea capensis woodland - 1 1 Woody r 1 2 - Protea caffra Woody 2 - - 1 Searsia leptodictya Woody 1 3 1 - Searsia magalismontanum Woody 2 1 6 2 Strychnos pungens Woody 2 - - 1 Ximenia caffra Woody + 1 - - Digitaria eriantha Grass r Eragrostis curvula– 2 - - Eragrostis curvula Grass 2 Stoebe vulgaris 1 - - Pentarrhinum insipidum Forb r grassland 1 - - Salacia rhemanii Forb 2 10 - 3 Burkea africana Woody 3 1 - - Cyperus congestus Sedge r 2 - - Diheteropogon amplectens Grass + 7 - - Eragrostis curvula Grass r 3 - - Fadogia homblei Forb 1 2 - - Loudetia simplex Grass 2 Fadogia homblei–Burkea - - 1 Ochna pulchra Woody + africana woodland 1 - - Pogonarthria squarosa Grass r 1 - - Salacia rhemanii Forb 2 2 - - Searsia pyroides Woody + 1 - - Setaria sphacelata Grass 2 - - 1 Strychnos cocculoides Woody r 2 - - Tristachya rhemanii Grass + Eragrostis curvula– - 1 1 Burkea africana Eragrostis gummiflua Woody 1 grassland aHatchlings, bSub-adult, cAdult,
101
4.3 DISCUSSION AND CONCLUSION
4.3.1 C. dilepis morphology and measurements
Differences in the SVL, STL and mass of male and female C. dilepis were statistically significant in adult C. dilepis. Measurements of all age classes combined showed that the SVL and STL were statistically higher in males. Higher observations of sub-adults and hatchlings compared to adults may have skewed the data in the morphology analysis of the combined age classes. The larger number of immature specimens compared to adults could have influenced the results as hatchlings and sub-adults did not show statistical intersexual variation in size and mass.
As found in other studies (Wager, 1983; Reaney et al., 2012), adult female C. dilepis during this study were generally larger than males. Larger female body size in reptiles is an adaptation to larger female productiveness and female C. dilepis invests largely in reproduction by producing large clutches of small eggs (Reaney et al., 2012). C. dilepis can carry up to 77 eggs internally before laying them (Jacobsen, 1989). Eggs make up a large component of a gravid female’s mass and with this Reaney et al. (2012) suggested that chameleons are capital breeders. Capital breeders invest large energy reserves into producing offspring (Bonnet et al., 1998) and organisms subjected to high mortality rates tend to allocate a greater proportion of energy into reproduction (Smith, 1977). During the study, some of the adult female C. dilepis were gravid with eggs and in some cases, the eggs could be seen protruding through the abdominal cavity, which contributes to the mass of the female. The heaviest gravid female weighed 65 grams, SVL = 120 mm, STL = 245 mm, compared to another that had recently deposited eggs (covered in mud and emaciated) and weighed 45 grams, SVL = 125 mm, STL = 260 mm. This last compared female was larger overall in length but weighed 20 grams less than the female with the shorter STL. The weight before she laid her eggs could not be established.
Telperion can be considered as a potentially unpredictable environment that is prone to drought and temperature variations between seasons. Aditional to climatic
102 changes, snakes, birds and smaller mammals that are potential predators of chameleons could expose C. dilepis to high mortality through predation, drought and extreme temperatures and investing in egg laying is a way of ensuring the survival of the species. The high numbers of hatchlings compared to the number of sub-adults and adults found at the end of the active season suggests that C. dilepis may have a high mortality rate from hatching to sub adult. The cost that females place into reproduction by laying large amounts of eggs and possibly depleting all of her resources to the detriment of herself may outweigh the investment of strong parental care. Huang et al. (2013) indicated that strong maternal care can only evolve in egg- laying lizards if parents are able to successfully defend offspring from predators without increasing predation risk to them. C. dilepis is not capable of defending its offspring against most predators known to have preyed upon chameleons. Newly hatched chameleons are the most vulnerable to predation at this stage as they are small enough to be eaten by most predators (Tolley & Burger, 2007). Therefore it is assumed that the species have a greater chance of survival by producing large clutches of eggs and leaving the hatchlings to fend for themselves after hatching.
Chameleons are likely to be short-lived and typical chameleons such as C. dilepis can reach sexual maturity within a year (Wager, 1983; Tolley & Burger, 2007). C. dilepis has been recorded to grow from 45 mm in length from a hatchling to 152 mm in total length in seven months eventually reaching a total length of 216 mm at 13 months (Wager, 1958). Brian (1961) recorded slower growth rates for C. dilepis that only reached sexual maturity at 2 years of age. Growth rates in most chameleon species have been recorded from captive species (Tolley & Herrel, 2014), however, some studies have compared captive with wild populations. In a study by Lin and Nelson (1980), the compared growth rates from captive juveniles of Trioceros hoehnelii and Trioceros jacksonii with wild recaptured specimens indicated that non- captive individuals had higher growth rates than captive individuals. Similarly, wild Chamaeleo namaquensis and Bradypidion pumilum also showed higher growth rates than captive ones (Burrage, 1972). Growth rates to sexual maturity between sexes may also differ amongst species as found in previous studies (Burrage, 1972; Lin & Nelson, 1980). The study by Lin and Nelson (1980) found that both sexes of T. hoehnelii matured within a year and T. jacksonii in just less than two years. In both T. hoehnelii and T. jacksonii, it was found that females matured 20% faster than males 103
(Lin & Nelson, 1980). Older studies on growth rates were conducted by Buragge (1972) on B. pumilum between birth and adulthood and found that growth rates vary during the year, with longer rates to maturity between March-May (240 days) compared to September – February (85 – 210 days). Burrage (1972) also found that C. namaquensis females reached maturity earlier than males at 150 days with an SVL of 75 – 80 mm, whereas males only reached sexual maturity at 210 days with an SVL of 70 – 75 mm. In dwarf chameleons such as B. pumilum, males mature at a smaller size (41 mm) than the females (53 mm) although both are mature at 18 months (Jackson, 2007). With the few studies done on the growth rates of chameleons and the limited data on growth rates obtained from the Telperion population, it motivates further study into the growth rate of C. dilepis.
Although mean perch heights between males and females were not significantly different in this study, personal observations noted variations in perch heights with males generally perching higher than females. O’Donoghue ( 1 ) noticed that gravid females perched lower and closer to the ground than non-gravid adult females, possibly to select suitable nesting sites. In this study, the lower perching of females did not correspond with observations of gravid females. Observations of females covered in mud indicated that they had recently laid eggsand during this study on Telperion such females perched at heights of 1.5 m to 2 m. Seasonal perch differences between the sexes of C. dilepis has also been noted in a study of habitat use in Kenya by Herbrard and Madsen (1984).
By failing to locate any hatchlings or sub-adults during the start of the rainy season in November 2016 until January 2017, the hatching of eggs is dependent on sufficient rainfall and is therefore very seasonal. The absence of sub-adults could possibly be that they do not survive dormancy or that they continue to grow whilst dormant by using body reserves built up and stored during the active season (Bartlett & Bartlett, 1995) and are therefore found as adults during this period.
4.3.2 C. dilepis habitat utilisation and dispersal
Adequate conservation of species requires a sound knowledge of habitat and resource requirements (Manly et al. 2002; Strickland & McDonald 2006; Baasch et 104 al., 2010) and it is crucial to understand what a species requires to fulfil its biological needs (Freitas et al., 2008). Habitat selection and dispersal of animals can be defined as choosing a place to live where it is mostly an involuntary reaction to certain key aspects of the environment and moving from one habitat to another (Drickamer et al., 2002). Quality and selection of habitats is an important part of an organism’s life history pattern and may also add to their reproductive success (Smith, 1977). When researching distribution and abundance of species, high population densities are usually found close to the centre of the species’ rangeand as the distance from the core increases so the abundance decreases (Drickamer et al., 2002).
The value of a habitat to an organism such as C. dilepis will depend on the availability of suitable nesting sites, perches and cover for escape as well as shelter (Smith, 1977) and food availability. Habitat units within the study area border one another, either as ecotones or immediate vegetation changes, for example, from woodland to grassland. C. dilepis can therefore potentially move from one habitat unit to the other.
Observations of viviparous dwarf chameleon species such as Bradypodion thamnobates have been seen moving out of woody vegetation to have its young in the open grassy areas (Tolley & Herrel, 2014). Other species such as Chamaeleo chamaeleon shows a similar habitat shift to avoid competition between juveniles and adults (Keren-Rotem et al., 2006). This ontogenetic habitat shift is suggested to ensure suitable habitat for foraging and resource availability of chameleon offspring by reducing intraspecific competition between different age classes (Kerem-Rotum et al., 2006; Tolley & Herrel, 2014).
Driving forces that cause C. dilepis to move from one area to another must be identified for every recorded habitat unit. They may be biotic and abiotic factors that motivate C. dilepis to use one habitat or multiple habitats. Each habitat unit (discussed in Chapter 3) has different characteristics and features such as rockiness, variation in soils, species richness, grassland, woodland and shrubland. Each purpose for the use of the habitat unit can be aligned with the chameleon’s requirement and with the characteristics of the habitat unit. 105
As with many species of animals, C. dilepis may require a combination of habitats to meet its life cycle requirements (Drickamer et al., 2002). Many lizards are not restricted to one type of habitat and they may thrive in a variety of habitats especially the types found in grasslands and savannas (Mattison, 1992).
All three age classes of C. dilepis identified in this study were located in six of the seven habitat units during the study period. Occupation of different habitat units was variable throughout the year and was utilized disproportionatly to the availability of the habitats. The observations of age classes also suggested a change in habitat utilisation at different growth stages. As no individuals were marked during this study the movements of individuals could not be confirmed, but a given age class was only found within certain time periods based on the results. This provides evidence that different age classes appear to have distinctive habitat unit preferences and it suggests that C. dilepis individuals disperse from the habitat unit in which they have hatched to habitats, which meet their resource requirements at different life stages. For example, surveys located hatchlings in grasslands and grassland associated sandy woodlands during January 2017 and February 2017 but no sub-adults were found during this period. Adult female C. dilepis were observed laying eggs and perching close to grassland habitats in February 2017 and observed perching further away from grassland habitats within the Loudetia simplex-Englerophytum magalismontanum woodland (habitat unit 4) from March 2017-May 2017. The presence of gravid females in grasslands only during certain times of the year suggested that these grasslands were used for egg laying which is conducive with the specific grassland associated areas on Telperion. From March 2017-May 2017 sub-adults were located for the first time during surveys and only in the rocky woodland habitat units. During this same period, the last hatchlings observed during the study were located in the rocky woodland habitat units. After May 2017 no more chameleons were located within the grassland and sandy woodland habitat units. This does suggest that the different age classes of C. dilepis were located in different habitat units. Adult C. dilepis were located throughout the active season from November 2016–May 2017 in all the habitat units except the Imperata cylindrica- Populus alba woodland (habitat unit 2), however, although adult C. dilepis were
106 located throughout the study period the adults especially females were found to occupy different habitat units during different times of the year.
Females determine the initial habitat for hatchlings by laying eggs in a suitable microhabitat. One gravid adult female C. dilepis was found in the Panicum maximum-Combretum erythrophyllum woodland (habitat unit 1) and another in the Acacia mearnsii woodland (habitat unit 3). During December 2017 in the Fadogia homblei-Burkea africana woodland (habitat unit 6) where most of the hatchlings were observed, four of the five adult C. dilepis observations were of gravid females. The occurrence of gravid females in the above habitat units corresponds to the habitat units that were identified as preferred by hatchlings in the habitat utilisation analysis.
Natural selection favours lizard genotypes that select nesting sites in habitats that promote developing strategies for their young to improve growth and development opportunities (Angilletta et. al.,2009). Soil type, soil moisture and substrate hardness in habitats will influence the amount of time and energy a chameleon invests during nest construction and egg laying. If the soil type and hardness are not suitable, chameleons may abandon the chosen nest location if the digging is too difficult (Mc Geough, 2016). In crocodiles, the soil substrate was an important factor when selecting a nest site and alluvial soils were the preferred soils for nesting sites (Summers, 2015). Soil moisture stability is an important factor when female chameleons choose a nest site and it may influence the nest site choice of a female chameleon (Tolley & Herrel, 2014).
Male adult C. dilepis were mostly found in the rocky woodlands of the Loudetia simplex-Englerophytum magalismontanum woodland (habitat unit 4). The occurrences of fewer adult C. dilepis (10 adult females and 9 adult males) than hatchlings and sub-adults within the different habitats during the study indicates that there may be a high mortality rate amongst C. dilepis as they mature. Another possible explanation is that adults were just not observed in the study plots. Female C. dilepis are exposed when moving long distances to search for an appropriate nesting site (Brian, 1961). Moving from dense woodland into open grassland associated vegetation when laying eggs increases the vulnerability of C. dilepis females to predation. Males may also cover large areas in search of a female 107
(Wager, 1983). Brian (1961) and Wager (1983) indicated that C. dilepis may cover large distances on the ground when food sources are scarce also exposing them to predation.
Different habitat unit utilisation patterns were noticed between hatchlings and sub- adults. When adults were located in habitats that were utilised less than expected and considered as avoided habitats, the adults observed were mostly females. In most animals species one sex is usually more likely to disperse than the other (Drickamer et al., 2002). Distances travelled from a specific habitat site during nest site construction and the search for food or a potential mate or the dispersal of hatchlings from a nest site, can force a chameleon to disperse into a certain direction. It may possibly never find a suitable habitat that meets its requirements and it may die or become prey. The presence of hatchlings in different habitats suggests that females use different habitats to oviposit.
The results from this study suggest that on Telperion C. dilepis had preferences for specific habitat units at different times of the year. The preference of hatchlings for habitat units such as the Fadogia homblei-Burkea africana woodland (habitat unit 6) and Acacia mearnsii woodland (habitat unit 3) suggests that these habitat units have characteristics that are crucial for the survival of this age classand was selected by females as habitats that will promote the survival of the hatchlings. Each habitat unit has different biotic and abiotic features that are either suitable or not suitable to the needs of C. dilepis. Their biotic and abiotic needs could differ during different times of the year. Variations in soil temperature, moisture levels, microclimates and vegetation cover at different times of the year, may provide suitable conditions at various life cycle stages of C. dilepis. Soil and soil depth may be important to a female chameleon for laying eggs at a certain time of the year, but when egg laying is not required then it reduces or eliminates the need for deeper soils and adults females may then move into other habitats. The same explanation applies to biotic factors such as plant structure at different times in the life cycle of the C. dilepis. When perch plants in a grassland habitat become too weak to support the weight of growing C. dilepis, they disperse to a woodland habitat where there is more robust vegetation such as shrubs and trees to support their weight. In other chameleon species such as Chamaeleo chamaeleon, denser vegetation structure was preferred 108 more than less dense vegetation by adults (Hódar et al., 2000) and the young of C. chamaeleon were found in lower vegetation where adults utilised trees and larger bushes (Keren-Rotem et al., 2006). Based on this habitat movement during different times of its life cycle causes C. dilepis to shift habitats to fulfil their needs at different times of the seasons when they are active.
4.3.3 Seasonality of C. dilepis
Seasonality is the occurrence of certain biotic and abiotic events within limited periods of a year (Leith, 1974) and seasonality in temperate habitats results largely from changes in photoperiod, rainfall and temperature, (Smith, 1977).
From the results of this study, C. dilepis on Telperion have seasonal habits which are in accordance with other studies of this species by Herbrard and Madsen (1984). At high elevated areas such as the Drakensberg, South Africa, chameleons may disappear or become dormant during cold winter months, even moving into houses where they are dormant for months (Tolley & Herrel, 2014). In an unpublished study by O’Donoghue ( 1 ) in the central bushveld regions of the Savanna biome in South Africa, C. dilepis showed a dormant stage with no observations during the dry winter months, only becoming active again after the first substantial rainfall. The relationship between environmental data and presence of C. dilepis indicates that there are external environmental forces such as rainfall and minimum temperatures that cause C. dilepis of the Telperion grasslands to become active, hatch from their eggs and in contrast to this active stage, enter a definite dormancy period, where they go without food and water for lengthy periods.
Some of the studies that have been done on C. dilepis by Herbrard and Madsen (1984) have suggested some degree of seasonality in density but little data exists as to where chameleons spend dry and colder winter periods (Wager, 1983). Chameleons rely on outside temperatures to regulate their body heat and require daily water intake for survival (Le Berre & Bartlett, 2009) either through drinking water or from water within food items (Tolley & Herrel, 2014). In the Highveld grasslands of South Africa, colder temperatures are associated with dry winters and less production during these periods (Mucina & Rutherford, 2006) that may cause 109 smaller reptiles such as C. dilepis of colder high elevated regions to brumate or from hotter tropical climates to aestivate (Bartlett & Bartlett, 1995). Brumation pertains to winter dormancy during extreme drops in temperature and aestivation to summer dormancy with high heat and dry summer periods (Bartlett & Bartlett, 1995). Hibernation is mostly related to an inactive sleep like state but not very well defined in ectotherms and torpor is a state of sleep where organisms drop their body temperatures to lower their metabolism (Sanders, 2008). In temperate climates, animal dormancy is mostly triggered by photoperiod and temperature (Smith, 1977). Chameleons, in general, have lower body temperatures than other lizards, around 20–30oC, suggesting that chameleons could adapt to colder temperatures (Tolley & Herrel, 2014). Telperion has cold winters (-4 ˚C min in July 2016) with hot summers (41 ˚C high in October 2017) and that chameleons inhabit Telperion may be that they can withstand the lower temperatures as well as dry periods by being seasonal. The climatic data compared with presence and absence of C. dilepis indicate that the seasonal activity and dormancy of C. dilepis at Telperion was influenced by minimum temperature and rainfall more than other climatic factors recorded. Although minimum temperatures also correlate with rainfall measured during the study the known need for moisture intake through available water within the environment (Tolley & Burger, 2007; Le Berre & Bartlett, 2009) is a known environmental requirement of chameleons that makes rainfall and presence or absence of precipitated water the main driving factor to prompt chameleons to either be active (present) or to be non-active (absent).
Besides reproduction efforts, food and water are crucial factors that chameleons need in order to survive. Both its food and water requirements are climate dependent (rainfall and insect availability) and more available during the hot rainy season than the colder dry season. Unfavourable climate suppresses insect activity and causes insects to react to these climantic conditions by also entering some form of diapause when seasonal conditions become unsuitable (Diniz et al., 2017). Insects are the main diet of C. dilepisand if dormancy was not part of C. dilepis’s biology, it may perish due to food shortages.
Wager (1983) found that unless a certain amount of rain occurs, the soil is too hard for the hatchlings to dig out of and will eventually die in their attempt to get out. The 110 absence of hatchlings prior to rainfall, suggests that hatching is seasonal and is stimulated by rainfall. Seasonal hatching behaviour has been found to occur in other chameleon species such as Furcifer labordi, which occurs in areas of Madagascar with highly seasonal climates (Karsten et al., 2008). C. dilepis hatchlings were found from January to March 2017, whereas no sub-adults were found from November 2016 to February 2017 but were then present in surveys until the end of May 2017. The results from this study, therefore, indicate that on Telperion, C. dilepis have a seasonal development as certain age classes were only found at specific times of the year. Cold winters at Telperion could slow down embryo development within the egg and cause C. dilepis nests to hatch during the same time of the year. The effect of cold temperatures on the delay of embryo development was shown by Andrews et al., (2008), by manipulating nest temperatures and proving that when cold temperatures rise after winter, chameleon egg development was activated by the warmer temperatures that cause synchronised development of all other eggs. Synchronous seasonal hatching has been documented in studies on other species of Chamaeleo by Ferguson et al. (2004) and it allows for the hatchlings to emerge from the eggs and nest sites during favourable times of the year when rainfall amounts are higher especially in areas that are known for dry seasonal periods (Le Berre & Bartlett, 2009).
4.4 REFERENCES
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ANGILLETTA JR, M. J., SEARS, M. W., & PRINGLE, R. M. (2009). Notes - Spatial dynamics of nesting behaviour: Lizards shift microhabitats to construct nests with beneficial thermal properties. Ecology. 90, 2933.
BAASCH D.M., TYRE A.J., HYGNSTROM S.E., MILLSPAUGH J.J., & VERCAUTEREN K.C. (2010). An evaluation of three statistical methods used to model resource selection. Ecological Modelling. 221, 565-574.
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BARTLETT, R. D., & BARTLETT, P. P. (1995). Chameleons everything about selection, care, nutrition, diseases, breedingand behaviour. Hauppauge, Barron's.
BONNET, X., BRADSHAW, D., & SHINE, R. (1998). Capital versus income breeding: An ectothermic perspective. Oikos –Copenhagen 83, 333-344.
BRAIN, C. K. (1961). Chamaeleo dilepis—A Study on its Biology and Behaviour. Journal of the Herpetological Association of Rhodesia. 15, 15-20.
BURRAGE, B. R. (1972). Comparative ecology and behaviour of Chamaeleo pumilus pumilus (Gmelin) and C. namaquensis A. Smith (Sauria: Chamaeleonidae). Ph.D. Thesis. University of Stellenbosch. http://hdl.handle.net/11070.1/3751.
CARPENTER, A. I., MARCUS ROWCLIFFE, J., & WATKINSON, A. R. (2004). The dynamics of the global trade in chameleons. Biological Conservation. 120, 295-305
DINIZ, D. F. A., DE ALBUQUERQUE, C. M. R., OLIVA, L. O., DE MELO-SANTOS, M. A. V., & AYRES, C. F. J. (2017). Diapause and quiescence: dormancy mechanisms that contribute to the geographical expansion of mosquitoes and their evolutionary success. Parasites & Vectors. 10, 1-13
DRICKAMER, L. C., JAKOB, E. M., & VESSEY, S. H. (2002). Animal behaviour: mechanisms, ecology, evolution. Whitehouse Station, McGraw-Hill.
FERGUSON, G., MURPHY, J. B., & RAMANAMANJATO, J. B. (2004). The panther chameleon: natural history, conservation, colour variation and captive management. USA, Krieger.
FREITAS, C., KOVACS, K. M., LYDERSEN, C., & IMS, R. A. (2008). A novel method for quantifying habitat selection and predicting habitat use. Journal of Applied Ecology. 45, 1213-1220.
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HEBRARD, J. J., & MADSEN, T. (1984). Dry Season Intersexual Habitat Partitioning by Flap-Necked Chameleons (Chamaeleo dilepis) in Kenya. Biotropica. 16, 69-72.
H DA , J. A., PLEGUEZUELOS, J. M., & POVEDA, J. C. (2000). Habitat selection of the common chameleon (Chamaeleo chamaeleon) (L.) in an area under development in southern Spain: implications for conservation. Biological Conservation. 94, 63-68.
HUANG, W.-S., PIKE, D. A., & SUEUR, C. (2013). Testing Cost-Benefit Models of Parental Care Evolution Using Lizard Populations Differing in the Expression of Maternal Care. PLoS ONE. 8.
JACKSON JC. (2007). Reproduction in dwarf chameleons (Bradypodion) with particular reference to B. pumilum occurring in fire-prone fynbos habitat. PhD thesis. University of Stellenbosch, South Africa.
JACOBSEN, N. H. G. (1989). A herpetological survey of the Transvaal. Biological Sciences University of Natal
KARSTEN, K.B., L.N. ANDRIAMANDIMBIARISOA, S.F. FOXand C.J. RAXWORTHY. (2008). A unique life history among tetrapods: An annual chameleon living mostly as an egg. National Academy of Sciences http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=2449350.
KEREN-ROTEM, T., BOUSKILA, A., & GEFFEN, E. (2006). Ontogenetic habitat shift and risk of cannibalism in the common chameleon (Chamaeleo chamaeleon). Behavioural Ecology and Sociobiology. 59, 723-731
LE BERRE, F., & BARTLETT, R. D. (2009). The chameleon handbook. Hauppauge, N.Y., Barron's.
LIETH, H. (1974). Phenology and seasonality modelling. Berlin, Heidelberg, New York, Springer.
LIN, J.-Y., & NELSON, C. E. (1980). Comparative Reproductive Biology of Two Sympatric Tropical Lizards Chamaeleo jacksonii (BOULENGER) and
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Chamaeleo hoehnelii (STEINDACHNER) (Sauria: Chamaeleonidae). Amphibia-Reptilia. 1, 287-311.
MANLY, B.F.J., MCDONALD, L.L., THOMAS, D.L., MCDONALD, T.L. & ERIKSON, W.P. (2002) Resource selection by animals: statistical design and analysis for field studies, Kluwer Academic Publishers, Dordrecht, The Netherlands.
MATTISON, C. (1992). Lizards of the world. London, Blandford
MCGEOUGH, R. (2016). Furcifer pardalis (Panther Chameleon) – A Brief Species Description and Details on Captive Husbandry. Biology, Engineering, Medicine and Science Reports. 2, 27-38.
MUCINA, L., & RUTHERFORD, M. C. (2006). The vegetation of South Africa, Lesotho and Swaziland. Pretoria, South Africa National Biodiversity Institute.
O’DONOGHUE, T.L. ( 1 ). The distribution difference of Flap-Necked chameleons (Chamaeleo. dilepis) in built up and non-built up environments within and eco-estate. Unpublished report. For partial fulfilment of B-Tech Nature Conservation. University of South Africa.
REANEY, L. T., YEE, S., LOSOS, J. B., & WHITING, M. J. (2012). Ecology of the Flap-Necked Chameleon Chamaeleo dilepis In Southern Africa. Breviora. 1- 18.
SANDERS, C. E. (2008). Quiescent states of sleep, torpor and hibernation in the Brazilian tegus (Tupinambis merianae). Vancouver, University of British Columbia. http://hdl.handle.net/2429/233
SMITH, R. L. (1977). Elements of ecology and field biology. New York, Harper & Row.
STRICKLAND, M. D., & MCDONALD, L. L. (2006). Introduction to the Special Section on Resource Selection. The Journal of Wildlife Management. 70, 321-323.
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SUMMERS, M. K. (2015). Aspects of Nile crocodile (Crocodylus niloticus) population ecology and behaviour in Pongolapoort Dam, KwaZulu-Natal. M.Sc. Dissertation. University of KwaZulu-Natal, Pietermaritzburg
TOLLEY, K., & BURGER, M. (2007). Chameleons of Southern Africa. Cape Town, Struik Publishers.
TOLLEY, K. A., & HERREL, A. (2014). The biology of chameleons. Berkeley, University of California Press.
WAGER, V. A. (1958). The chamaeleon's breeding habits. 12: 285-293.
WAGER, V. A. (1983). The life of the chameleon. A Wildlife Handbook. Durban, South Africa, Natal Branch of the Wildlife Society.
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CHAPTER 5 – DISCUSSION
5.1 INTRODUCTION
The data analyses in the preceding chapters 3 and 4 have shown that the seven habitats at Telperion were suited or unsuitable to C. dilepis at different times of the year. Different habitats were also preferred during different stages or age classes of the life cycle of C. dilepis. This could be that the preferred habitats suited their biological needs during different stages of its life cycle or they were randomly selected by chance.
Each habitat unit that was classified during this study has characteristics that distinguish it from another which may have been suitable for different age classes. Habitats may have been preferred or avoided in terms of similarities or differences between soils, vegetation structure and plant densities, plant species richness and/or plant species diversity. Chameleons and other reptiles select habitats based on habitat characteristics that are suitable for resource availability, reproduction, conspecific avoidance and shelter to avoid predation and to brumate (Le Berre, 2009).
The physical activities of chameleons are affected by the differences in seasons and the chameleon relies on suitable habitat for it to brumate in (Le Berre, 2009). It was not determined or tested where they spend the dry and cold winter at Telperion. The data showed that C. dilepis move to habitats with more diverse, dense and robust structure in terms of vegetation, rockiness and soil type toward the dry season. The seasonal behaviour of C. dilepis corresponds to most lizards in temperate environments and the places sought out where to spend their dormancy may be similar to other lizards (Bauwens, 1981). Similarly, the morphology of C. dilepis between sexes may be an important aspect in the reproduction success of C. dilepis. Differences in sizes between sexes have been extensively studied in other lizards (Butler et al., 2000; Cox et al., 2007; Herrel et al., 2009; Cox & Calsbeek, 2010; Berns, 2013; Garc a-Navas et al., 2016) and the results of this study found
116 similarities to these studies where morphological differences between the sexes of C. dilepis were found.
To suggest why morphological differences, seasonality and preferences toward different habitat units at different life stages were important to C. dilepis, this chapter will discuss and compare the various habitat unit traits, possible reasons for dormancy and importance of sexual size dimorphism in C. dilepis.
5.2 DISCUSSION
5.2.1 Morphology
In the majority of lizards males are larger than females, but in certain cases, females are larger than males (Cox et al., 2007). In chameleons, the differences in body size between sexes vary from larger female or larger male body sizes (Tolley & Herrel, 2014). In Bradypodion species males and females may be larger than one another, although in most of the cases females are larger than males (Stuart-Fox, 2009). In this study, the morphological measurements in body size and mass between the sexes of adult C. dilepis were significantly different. The result showed that females have the larger body size between sexes and female-biased sexual size dimorphism between male and female C. dilepis at Telperion exists.
Herrel et al. (2009) state that specialised morphological traits between the different sexes of a species can be the result of natural selection on an ecological requirement of the species. Three types of sexual dimorphisms that are influenced by natural selection have been identified by Darwin (1859). These types are those resulting from intersexual competitiveness or sexual selection for a mate, habitat partitioning or differences in the use of habitats between sexes, and differences in the reproductive roles of the two sexes where fecundity selection favours large females to produce more offspring (Butler et al., 2000). Another reason for sexual size differences may be as a result of differences in food sources in terms of prey size (Cox et al., 2007).
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Male lizards that have fixed territories are usually larger than females and larger males have better success at finding a mate due to intra-sexual competition or females will choose a larger male (Cox et al., 2007). In terms of intersexual competitiveness C. dilepis males are not known to occupy a fixed territory to defend (Brian, 1961). Physical confrontations between C. dilepis males is rare but males will not tolerate any conspecifics in their presence and may fight during encounters in the vicinity of a receptive female (Brain, 1961). Female C. dilepis will show the same reaction toward other females and even toward a male if she is not ready to mate or if she has already mated (Brain, 1961). Females may mate with multiple males at different times during her receptive cycle (Wager, 1983). When taking multiple mating into account and the method of mate selection where a male finds a female, male and female C. dilepis’ sexual size dimorphism does not appear to be because of intersexual competitiveness.
Sexual dimorphism in C. dilepis does not play a role in habitat partitioning. The only differences observed in the use of preferred habitats were the use of more open grassland associated woodland areas by females in which to lay their eggs. If the size of the female C. dilepis is considered when shifting habitats, it could be suggested that when females are more exposed in open areasand when they lay eggs a larger female may be less preferable to a predator in open habitat. This has not been tested and the range of physical size differences between sexes is not that large that it would deter predation. Keren-Rotem et al. (2006) mention common predators that will prey on Chamaeleo chameleon are similar to the predators such as snakes and birds that have been documented as common predators of C. dilepis (Wager, 1983; Tolley & Burger, 2007). In terms of predator avoidance chameleons cannot outgrow most predators in the habitats that they utilise (Kerem-Rotem et al., 2006). Therefore sexual size dimorphism in C. dilepis is not a strong indicator of predator avoidance. Perch heights between males and females did not indicate habitat partitioning as there were no significant differences recorded in the height perched between the sexes in adults.
C. dilepis is a widespread chameleon (Tolley & Burger, 2007) and the habitats that C. dilepis is found to occupy, can vary in terms of climate extremities. In some lizard species, a reproductive female may use nearly twice of the body’s metabolic 118 generated energy as what is used by males (Merker & Nagy 1984; Orrell et al. 2004). Wager (1983) observed a female C. dilepis may die from exhaustion after ovipositing with high inputs of energy resources to egg production she may deplete her resources and not live to lay a second clutch of eggs in her lifetime. The varying conditions of the environment inhabited by C. dilepis may drive this chameleon to invest higher energy rates in egg laying and reproduction rather than maternal care (Reaney et al., 2012). The sexual size differences between adult C. dilepis may have developed over time to suit a specific requirement in order for the species to survive, such as producing more offspring because fecundity favours larger body size in females, more eggs can be produced (Burrage, 1972; Lin & Nelson, 1981; Cuadrado, 1998, Berns, 2013). The larger body size of the female C. dilepis correlates to egg clutch size (Reaney et al., 2012), however Burrage (1972) observed that in Chamaeleo namaquensis the size of the egg clutch was not in relation to the size of the laying female but in relation to the time of the year that the eggs were laid.
5.2.2 Habitat preference
During this study, varying densities of different age classes of C. dilepis were found in the various habitat units utilised by C. dilepis.
In the habitat units where hatchlings were located, some biotic and abiotic components of the habitat units are suggested to be selected by gravid females to utilise a particular habitat unit as a suitable nest site to lay their eggs. For example the habitat units may have similarities or differences that may ease nest construction, adequate protection against predators and plants suitable for perching, a source of nutrition for the hatchlings during the first stages of their lifecycle and also the connectivity with other habitats that hatchlings will disperse to as they grow and when the hatchlings resource requirements change. Woody vegetation structure (tree and shrub density, tree and shrub canopy volume and tree and shrub height), plant species richness and diversity, slope, herbaceous cover, soil characteristics (depth, moisture, texture and rockiness) is discussed here.
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The highest number of hatchlings were found in the Fadogia homblei-Burkea africana woodland (habitat unit 6) followed by the Acacia mearnsii woodland (habitat unit 3). Observations of hatchlings in the Panicum maximum-Combretum erythrophyllum woodland (habitat unit 1), the Loudetia simplex-Englerophytum magalismontanum woodland (habitat unit 4) and the Eragrostis curvula-Stoebe vulgaris grassland (habitat unit 5) were observed in lower numbers than in the Fadogia homblei-Burkea africana woodland (habitat unit 6) and the Acacia mearnsii woodland (habitat unit 3). There were no observations of hatchlings within Imperata cylindrica-Populus alba woodland (habitat unit 2) or the Eragrostis curvula-Eragrostis gummiflua grassland (habitat unit 7).
A notable similarity between the Panicum maximum-Combretum erythrophyllum woodland (habitat unit 1), the Acacia mearnsii woodland (habitat unit 3) and the Fadogia homblei-Burkea africana woodland (habitat unit 6) is that they have the highest shrub canopy volume and shrub height of all the habitat units. Where hatchlings observations were lower in the Loudetia simplex-Englerophytum magalismontanum woodland (habitat unit 4) and the Eragrostis curvula-Stoebe vulgaris grassland (habitat unit 5) also had lower shrub canopy volumes and lower shrub height. The Eragrostis curvula-Eragrostis gummiflua grassland (habitat unit 7) had the lowest canopy volumes and shrub height recorded with no hatchlings observed in this habitat unit.
All the habitats where hatchlings were observed had varying tree cover with adequate shrub canopy cover. The only habitat where hatchlings were found without a well-structured tree and shrub layer is the Eragrostis curvula-Stoebe vulgaris grassland (habitat unit 5). The Eragrostis curvula-Stoebe vulgaris grassland (habitat unit 5) has recovered over time into secondary open grassland that was previously disturbed by agriculture. Although it does not contain a true woody plant component this grassland habitat’s vegetation structure contains a dense dwarf shrub layer that provides high shrub canopy cover. It may be that the Eragrostis curvula-Stoebe vulgaris grassland (habitat unit 5) has been favoured by female C. dilepis as a nesting site, because of the high dwarf shrub canopy volume or that C. dilepis prefers old cultivated areas similar to Chamaeleo chamaeleon that utilises old fields as preferable habitat (Hódar et al., 2000). Studies in European climates found that 120 cultivated areas were favourable habitat for the Chamaeleo chamaeleon and they were found more often in these areas than in natural areas (Hódar et al., 2000). In grasslands that were previously modified, there is evidence to suggest that these secondary grasslands contain a lower number of reptile species than untransformed grasslands (Masterson et al., 2009) and the lower vegetation cover can increase predation rates upon reptiles that occur within such grasslands (Castellano & Valone, 2006). The open structure and low growing habits of the dwarf shrubs of the Eragrostis curvula-Stoebe vulgaris grassland (habitat unit 5) are likely to increase exposure of newly hatched C. dilepis. This could, in turn, increase the predation rate and contribute to the low observations in this habitat unit compared to other habitat units with denser vegetation cover such where more hatchlings were observed. Mortality is known to be high as soon as hatchlings emerge from the nest and start to move into the surrounding vegetation (Tolley & Herrel, 2014) and denser more robust canopy cover is a requirement to protect hatchlings from predators especially where they emerge from the nests (Le Berre, 2009). This comparison of the woody layers suggests that a higher shrub canopy volume is preferred by female C. dilepis when selecting a habitat unit as a nest site.
The slope of the habitat units in which hatchlings were located was flat to slight except for the Loudetia simplex-Englerophytum magalismontanum woodland (habitat unit 4) where the slope varied from mild to steep but hatchlings were only located on the mild foot slope within this woodland habitat unit.
Plant species richness and plant species diversity was lowest in the Acacia mearnsii woodland (habitat unit 3) and the Fadogia homblei-Burkea africana woodland (habitat unit 6). The plant species richness and plant species diversity was higher in the Panicum maximum-Combretum erythrophyllum woodland (habitat unit 1), the Loudetia simplex-Englerophytum magalismontanum woodland (habitat unit 4) and the Eragrostis curvula-Stoebe vulgaris grassland (habitat unit 5) as aposed to the other habitat units described. The presence of hatchlings in habitats with low and high plant species richness and plant species diversity suggests that the heterogeneity or homogeneity of the vegetation does not influence the female C. dilepis in choosing a habitat as a nest site. In contrast with the latter statement, the higher observations of hatchlings in the habitat units with low plant species richness 121 and plant species diversity does correspond with the Bonferroni confidence intervals in the results of Chapter 4. Habitat units with high diversity and species richness were avoided as suitable nest sites by female C. dilepis.
Hatchlings in the Fadogia homblei-Burkea africana woodland (habitat unit 6), were observed using microhabitats formed by the vegetation structures in this habitat. The use of smaller microhabitats may also be a requirement during different stages of C. dilepis’ life cycle. Reptile microhabitats include a multitude of smaller habitats within a larger ecosystem that can be determined by the soil type, specific vegetation, slope, temperature, aspect and water availability (Mc Diarmid, 2012). The microhabitats in the Fadogia homblei-Burkea africana woodland (habitat unit 6) are created by the combination of growth forms of the shrubs Gymnosporia buxifolia, Searsia magalismontana and herbaceous forbs Fadogia homblei and Salacia rhemanii. The plants grow densely together, in patches, at random intervals within the habitat units. Tall robust grasses such as Diheteropogon amplectens, Digitaria erianthaand Themeda triandra are protected from grazing by larger herbivores amongst the shrubs. These grasses grow out and extend above the shrubby undergrowth where hatchlings then used these grasses as perches surrounded by a shrub habitat. Different structural features within the larger habitats (Clemann et al., 2008) such as a grassy clump, open meadow, marshy area or rocky outcrop can be classified as a microhabitat (Mc Diarmid, 2012). The undergrowth is characteristic of clump-forming vegetation and is utilised during the day as protection or possible shelter from elements and it could house insects as food. The clumps of specific plant species have been recorded as microhabitats (Kacoliris et al., 2009) and it provides suitable shelter, basking opportunities and specific prey items to reptiles ( eirāns, 7) and in this study it suggests to have the same benefit to C. dilepis hatchlings. This microhabitat use was only observed in C. dilepis hatchlings (Figure 5.1).
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Figure 5.1: A hatchling C. dilepis perching on Diheteropogon amplectens with Fadogia homblei undergrowth as a possible microhabitat. Photo by T.L. O’Donoghue
The Acacia mearnsii woodland (habitat unit 3) was transformed by alien clearing operations and the incidental fire that moved through this habitat unit changed the herbaceous vegetation and the woody vegetation composition. The fire also affected the adjacent Eragrostis curvula-Stoebe vulgaris grassland (habitat unit 5) that had a small portion transformed by the fire. The re-coppicing of trees caused the shrub layer to become densifiedand the herbaceous layer that was once a dense stand of grasses within and surrounding the habitat unit was transformed to short lawn forming grasses and some robust forbs. Hatchlings in the Acacia mearnsii woodland (habitat unit 3) were emaciated and appeared undernourished. The change in herbaceous vegetation could have affected the insect population densities available as food to hatchlings. Acacia mearnsii was left to dominate with some forbs and pioneer grasses and studies have shown that Acacia mearnsii have a negative effect on arthropods (Clusella-Trullas & Garcia, 2017) and without the co-dominance of a vigorous grass sward that was there before the fire could have inversely affected the
123 habitat unit for hatchlings in terms of food availability. The once dense herbaceous layer where females laid their eggs was transformed by the fire at the time hatchlings emerged from the nests. Another alternative is that female C. dilepis did not actually use the Acacia mearnsii woodland (habitat unit 2) as a nest site, but females may have rather used the adjacent Eragrostis curvula-Stoebe vulgaris grassland (habitat unit 5) instead. It could be that the fire deteriorated the habitat structure for hatchlings when they emerged from the nests. Hatchlings would then have been required to disperse into the Acacia mearnsii woodland (habitat unit 3) because of no or lower herbaceous plant cover in the Eragrostis curvula-Stoebe vulgaris grassland (habitat unit 5).
The presence of hatchlings in the habitat units that were affected by the fire indicate that C. dilepis nests are not affected by surface fires and that the eggs in the soil have a high probability to survive a fire when one does move through a habitat unit. Studies on the effects of surface fires on soils have found that dry soils are poor conductors of heat and thereby do not heat substantially at 50 mm below the surface unless heavy long-burning fuels are combusted (Beyers et al., 2005).
The female C. dilepis constructs a nest by digging with her head and forelimbs (Brain, 1961; Wager, 1983) to create an elongated chamber-like hole at a 45-degree angle into the ground (Burrage, 1972). The majority of chameleon species select areas with sandy soils, or soils with a sandy texture (Le Berre, 2009) and species such as C. dilepis prefers rain moistened soils so that the digging of the nest is less difficult (Burrage, 1972). The digging of nest sites after rainfall events coincides with observations made at Telperion during this study. Females observed constructing nests or that have recently deposited their eggs were covered in mud from nest construction activities indicating that the soils were wet when nest construction took place. When the effort of excavating the nest site becomes too difficult because of shallow rocky soils or hard texture the female will abandon the area and move to another area that is potentially more suitable (Brian, 1961). C. namaquensis in captivity will dig test holes in order to find the right nesting conditions and females would only start laying eggs when a layer of soft saturated sand was provided (Burrage, 1972). In the wild C. namaquensis females will lay eggs in gravel type soils usually at the foot slope of a high sand dune (Burrage, 1972). Chameleons choose 124 nest sites carefully before laying their eggs because the soils require correct soil moisture, temperature and adequate vegetation cover eventually for the hatchlings to disperse (Le Berre, 2009). In terms of soil type and nest site location the known explanations that can influence the poor survival of nest sites in oviparous reptiles is saturated soils and/or saturated substrate that eggs are deposited withinand predation (Montgomery et al., 2011).
Both the Fadogia homblei-Burkea africana woodland (habitat unit 6) and the Acacia mearnsii woodland (habitat unit 3) have well-drained sandy textured soils. The rockiness in these two habitats is low to noneand the soil depth is suitable for C. dilepis to nest in. The high observations of hatchlings in the Fadogia homblei-Burkea africana woodland (habitat unit 6) and the Acacia mearnsii woodland (habitat unit 3) indicate that the soil conditions in the habitats were adequate soils to incubate the C. dilepis eggs. The other habitats where hatchlings were also observed have adequate soils for egg laying because of the occurrence of hatchlings in these habitats. The fewer hatchlings observed in the Panicum maximum-Combretum erythrophyllum woodland (habitat unit 1), the Eragrostis curvula-Stoebe vulgaris grassland (habitat unit 5) and the Loudetia simplex-Englerophytum magalismontanum woodland (habitat unit 4) may have been influenced by differences documented in the soil conditions during this study and these will be discussed for each of the habitats in terms of soil depth, moisture levels and texture. C. dilepis eggs have a leathery outer shell (Wager, 1983) and reptile eggs with this type of outer shell are permeable and allow for gaseous and water diffusion to occur (Le Berre, 2009). When soils used as nesting sites by most oviparous reptiles have too high levels of either moisture or temperature it may be to the detriment of the survival of the eggs (Warner & Andrews, 2002).
The Panicum maximum-Combretum erythrophyllum woodland (habitat unit 1) has clayish soils with sandy alluvial deposits at different depths on the embankments. The sandy soils do not occur throughout this habitat unit as a result of changing rockiness below the soil surface. Soil moisture in the Panicum maximum-Combretum erythrophyllum woodland (habitat unit 1) fluctuates seasonally, depending on the amount of rainfall at Telperion. This riparian habitat unit has all the characteristics for female C. dilepis to use as a nesting area, but it may be that the egg survival ratio is 125 affected by the fluctuating water in the soils as a result of seasonal flooding. The Wilge River flows through this habitat unit and makes soils susceptible to flooding during the rainy season (Swanepoel, 2006). Flooding occurred at the end of 2016 and occasionally throughout the rainy season of 2017 during the study period, prior to the first recordings of hatchling in this habitat unit 1 (pers. obs). Studies on reptile egg survival have reported that flooding might be a cause for reptile nest failure (Moll & Legler, 1971; Janzen, 1994). The flooding of river banks and surrounding areas affected by floods may submerge a nest site and can potentially cause the direct death of developing eggs (Montgomery et al., 2011).
Although sufficient water is necessary for embryo development (Packard, 1999), the egg cannot withstand being surrounded by too much water for lengthy periods that will cause the embryo not to hatch (Gettinger et al. 1984; Tucker & Paukstis, 2000) or it may die from drowning (Keller,2017). The soils within the Eragrostis curvula- Stoebe vulgaris grassland (habitat unit 5) are similar in texture, depth and rockiness to the soils within the Fadogia homblei-Burkea africana woodland (habitat unit 6) and the Acacia mearnsii woodland (habitat unit 3). The soils of the Eragrostis curvula- Stoebe vulgaris grassland (habitat unit 5) however were not as well drained and the sandy soils remained moist throughout the study period. High rainfall recorded during the study period may have further increased the moisture levels in the soil of Eragrostis curvula-Stoebe vulgaris grassland (habitat unit 5) and contributed to poor egg development. The higher potential for moisture in nest sites will increase the risk of fungal infections and the invasion of microorganisms that will predate on the eggs (Tracy, 1980). Fungal infections can reduce gas exchange within the eggs and the embryos will die (Packard & Packard, 1984). High moisture levels and flooding of the soils in the Panicum maximum-Combretum erythrophyllum woodland (habitat unit 1) and Eragrostis curvula-Stoebe vulgaris grassland (habitat unit 5), higher moisture may have influenced hatches of C. dilepis eggs negatively.
There were similarities in the herbaceous cover of the habitat units where hatchlings were located, especially in terms of the grass sward and forb layer, however, the difference in herbaceous species composition may have contributed to different soil conditions that could have had an influence on the occurrence of hatchlings. This change in the soil moisture content as a result of the herbaceous plant species 126 occurring in the habitat unit was documented in Fadogia homblei-Burkea africana woodland (habitat unit 6). Within the Fadogia homblei-Burkea africana woodland (habitat unit 6), two plants namely Pteridium aquilinum and Fadogia homblei dominate different areas of the herbaceous layer at different sections of this habitat unit. In the areas where Pteridium aquilinum dominates, the soils have a higher moisture content compared to the areas where the forb Fadogia homblei is dominant. The Fadogia homblei dominated areas have soils with lower moisture content and these soils are well drained compared to the Pteridium aquilinum dominated soils. In the Fadogia homblei dominated sections of the Fadogia homblei- Burkea africana woodland (habitat unit 6), the observations of C. dilepis hatchlings were the highest of all the habitat units. No hatchlings were observed in the areas dominated by Pteridium aquilinum where the soil moisture is high. Where soil moisture is higher and soils are not well drained the assumption is that these high water levels may have contributed to poor hatches of C. dilepis eggs.
The soils in the Loudetia simplex-Englerophytum magalismontanum woodland (habitat unit 4) were shallow and loamy with high humus content and had no similarity to any of the other habitat units where hatchlings were located. These soils were on exposed rocky areas. The soils were dry and did not retain any moisture adequately and it appeared not to be adequate for nest sites. In contrast with the deep sandy soils of habitats preferred by hatchlings and these poor soil characteristics hatchlings were located on the foot slopes of this habitat unit near the ecotones with the Eragrostis curvula-Stoebe vulgaris grassland (habitat 5). Only 5 hatchlings were located in the Loudetia simplex-Englerophytum magalismontanum woodland (habitat unit 4) and only observed in January 2017 (n= 1) and in March 2017 (n=4). It is possible that the eggs laid in this habitat unit hatched in January 2017 with poor results rate due to the inadequacy of the habitat soils. In March most observation consisted of sub-adults and it could be that in March 2017 hatchlings dispersed from the adjacent habitats into this woodland. The only habitat that had soils similar to the Loudetia simplex-Englerophytum magalismontanum woodland (habitat unit 4) was the Eragrostis curvula-Eragrostis gummiflua grassland (habitat unit 7) and in this habitat, no hatchlings were observed during the study. The soils here are loamy and shallow on hard rock. They would not have been preferred by females for nest construction. 127
The soils of the Imperata cylindrica-Populus alba woodland (habitat unit 2) has no similarities to any other habitat unit in Telperion. The Imperata cylindrica-Populus alba woodland (habitat unit 2) is the only wetland associated habitat unit that has similarities to the Panicum maximum-Combretum erythrophyllum woodland (habitat unit 1) in terms of hydrology. In this case, both these habitats have a flowing perennial water source with surrounding woodland. In the case of the Imperata cylindrica-Populus alba woodland (habitat unit 2), the mostly water submerged woodland is dominated by the alien tree Populus alba and has been transformed from a grassland dominated wetland system to a dense Populus alba dominated woodland. No C. dilepis of any age class were observed in this habitat. The discussion regarding this habitat unit is applicable to all C. dilepis age classes because of the various influences the abiotic and biotic structure may have on the absence of C. dilepis in this habitat unit.
In the Imperata cylindrica-Populus alba woodland (habitat unit 2) many factors contribute to the absence of C. dilepis. The first and most noticeable is the total dominance of alien plants that compete with indigenous vegetation. Alien vegetation can transform an entire ecosystem to the determent of the indigenous fauna and flora (Crooks, 2002). In this habitat unit the alien trees were introduced into grasslands where they did not occur naturally. Trees introduced into grasslands where they did not occur previously have a higher absorption of water from the soils that may alter the soil properties and cause salinization that may affect the acidity of the soils (Jobbágy et al., 2008) in the ecosystem. Soil acidity affects the embryonic development of soft-shelled lizard eggs negatively (Marco et al., 2005). Although the soil pH levels were not tested in the various habitat units it still remains a possibility that Populus alba could have an effect on the acidity of the soil that could have an influence on C. dilepis egg development in the Imperata cylindrica-Populus alba woodland (habitat unit 2). The habitat unit is prone to flooding and fluctuating wetness of the soils in this habitat has the potential to cause C. dilepis eggs to drown. The high root growth in the upper horizons of a wetlands soil profile increases the porosity and this contributes to the water retention ability of the soils (Kotze et al.,1994). Soil structure in the Imperata cylindrica-Populus alba woodland (habitat unit 2) are vertic clays with high organic content (Swanepoel, 2006) in the form of 128 grassroots. The soils in the habitat unit are further compacted and trampled by game, therefore, nest construction for C. dilepis females will be a difficult activity in this habitat unit. In this Imperata cylindrica-Populus alba woodland (habitat unit 2) tall dense growing grasses have a high mat forming herbaceous cover throughout the year and the roots of these grasses penetrate the soils at a greater depth than other habitats. The root system of grasses and plants growing in wetlands can penetrate the soils to a depth of 50 cm (Rand water SA, 2000). Reptile nests such as those of the Leopard tortoise (Geochelone pardalis), have been affected by grassroots growing through the egg clutch through the egg chamber and contributed to hatch failures (Patterson et al., 1989). If a female C. dilepis manages to construct a nest in the Imperata cylindrica-Populus alba woodland (habitat unit 2) at a depth of 25 cm- 70 cm at an angle (Burrage, 1972), the vigorous growing grassroots will still manage to grow through a chameleon nest burrow site and prevent eggs from hatching. In grasslands such as Telperion, the roots of grasses will continue to grow during autumn toward winter as grass plants are still capable of photosynthesis during autumn and springtime (Tainton, 1999). This happens when the grasses invest more into the growth of roots than into foliage during unfavourable times of the yearand therefore growth conditions underground will still be suitable and root growth may still be high during winter (Tainton, 1999). These periods of high root growth in grasses during unfavourable times are also when chameleon eggs are in diapause before embryonic development in the nest sites (Tolley & Herrel, 2014). The Imperata cylindrica-Populus alba woodland (habitat unit 2) is a harsh habitat that is in most ways not suitable to C. dilepis and as shown by the results it was avoided by all age classes.
When C. dilepis and other chameleon hatchlings do successfully hatch from their nest site they disperse into the nearby vegetation (Brian, 1961; Wager, 1983; Le Berre, 2009; Tolley & Herrel, 2014). In this study, hatchlings were observed and monitored where they dispersed from nest sites they have hatched out of and moving into the adjacent vegetation. Hatchlings could have dispersed away from nest sites before they were observed in high numbers in habitat units where low numbers were recorded. Faster dispersal rates were recorded by Brian (1961) with observations of C. dilepis hatchlings dispersing from the nest into the surrounding vegetation covering an area of 0.25 acres (1011.74 m2) within a day. In this study, 129 the daily dispersal rate was noted as less than that recorded by Brian (1961). The nest site monitored for dispersal rates in this study measured a surface area of 4.28 m2 on the first day and after 14 days the total distance from the original nest location was 38.9 m away.
Closer to the end of the rainy season in March 2017 C. dilepis observations shifted from grassland associated habitat units to the denser woodlands of the Loudetia simplex-Englerophytum magalismontanum woodland (habitat unit 4). The movement from grassland to woodlands relates to the arboreal habits of the majority of chameleons (Herrel et. al., 2013).
A smaller amount of hatchlings were located in the Loudetia simplex-Englerophytum magalismontanum woodland (habitat unit 4) compared to other habitats and observations were only of sub-adults and adults from April 2017. The most observations of C. dilepis sub-adults and adults were observed in the Loudetia simplex-Englerophytum magalismontanum woodland (habitat unit 4). The vegetation structure in the rocky woodlands differed from grassland and grassland associated woodlands. The rocky woodland habitat unit consisted of a tree and shrub layer with a lower density than the Acacia mearnsii woodland (habitat unit 3) but higher tree and shrub densities than the Fadogia homblei-Burkea africana woodland (habitat unit 6). The tree and shrub canopy volume was the lowest of all the woodland habitat units and the tree and shrub heights were lower than the other woodland habitats. Higher trees and shrub densities provide adequate structure and habitat connectivity that assists reptiles to move uninterrupted (Edgar et al., 2010) and chameleon movement between habitat fragments (Tolley et al., 2010). A higher vegetation density enables smaller animals to find hiding places and escape from predators such as birds and mammals (Vitz & Rodewald, 2007).
Plant species richness and species diversity were the highest in the Loudetia simplex-Englerophytum magalismontanum woodland (habitat unit 4). Insect species prefer tree and shrub layers and occur in higher abundances per unit area compared to habitats with more homogenous structures such as grasslands (Botha et al., 2016). As C. dilepis grows, so does its nutritional needs. The volume of food required by larger chameleons will increase as the body size of C. dilepis 130 increasesand larger body size correlates with the prey size eaten by C. dilepis (Reaney et al., 2012).
The growth of C. dilepis increases their weight along with their limbs such as feet. Herrel et. al. (2013) studied the perching capabilities and grip performance of chameleons and found that plant perches are not selected based on available perches but are more related to the chameleon's hand and foot size to obtain a better grip during perching. This relationship between grip performances and perch size diameter ensures that a good grip is maintained during perches at night (Tolley & Herrel, 2014). At Telperion as C. dilepis hatchlings grow into sub-adults their perch plant requirements changes. The smaller feet of hatchlings may grip better on grasses and forbs but as C. dilepis grow into sub-adults and gain weight the perch diameters may be too small to maintain the grip. More robust vegetation, especially in the form of woody plants, is better suited as perch plants and shelter to larger chameleons than they are to hatchlings. Weight gained as C. dilepis age will make the chameleon too heavy for grass and forb plant perches. Increased weight means that a sagging plant without the rigidness to maintain a chameleon’s body weight as a stable perch will not be suitable any longer. The chameleon's perch plant may assist a sleeping chameleon with predator detection. When a predator tries and approach the sleeping chameleon on a branch the movement of the branch makes the chameleon aware of the threat and it may escape by moving into adjacent vegetation or drop to the ground (Tolley & Herrel, 2014).
The movement toward areas with more rock cover could be coincidental with the denser woody layer growing within the rocky areas, but rocky areas may have certain advantages to the chameleon. The timing of the habitat shift may also relate to finding shelter during dormancy at end of the rainy season. The rocky terrain in the Loudetia simplex-Englerophytum magalismontanum woodland (habitat unit 4) forms various cave-like overhangs and crevices that could supply a suitable microhabitat to spend dry and cold winters. Wager (1983) noted that dormancy or hibernation may occur in a hollow stump or similar excavated area (Wager, 1983) or that C. dilepis may burrow underneath other supporting structures such as flat rocks to brumate (Bartlett & Bartlett, 1995).
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Fire is not likely to be a threat to chameleons during the rainy season when they are active, however dry winters at Telperion are prone to incidental fires. During dormancy periods in dry winter months, the Loudetia simplex-Englerophytum magalismontanum woodland (habitat unit 4) may be a suitable protective area for adults and sub-adults against fires that are known to move through highveld grasslands (Mucina & Rutherford, 2006). Vegetation in the rocky areas of grasslands are protected against fire. Fire does not reach these rocky areas easily which allows for fire-sensitive species to escape or find refuge in rocky terrain (Cadman, 2013).
Sub-adult C. dilepis was observed in lower numbers within the Panicum maximum- Combretum erythrophyllum woodland (habitat unit 1) and although the tree and shrub densities in this habitat are lower than other woodland habitats at Telperion the vegetation structure and canopy cover are still suitable for growingand larger chameleons because of its woodland characteristics. In terms of plant species diversity and plant species richness, the Panicum maximum-Combretum erythrophyllum woodland (habitat unit 1) has the fifth highest plants species diversity and the fourth highest plant species richness. In comparison with other habitat units this habitat, unit falls in the middle section of plant species diversity and plant species richness. The riparian habitat unit and its vegetation structures are suitable for all age classes in terms of resources. The riparian Panicum maximum- Combretum erythrophyllum woodland (habitat unit 1) had observations of C. dilepis of all age classes throughout the study period and the sense of balance between the woody characteristics, plant species diversity and species richness and soil characteristics could make it a suitable habitat for all age classes. Adult females used the Panicum maximum-Combretum erythrophyllum woodland (habitat unit 1) as a suitable nest site as indicated by the presence of hatchlings and non-gravid adult females were also observed in this habitat unit. Riparian woodlands provide evergreen vegetation for year-round plant cover and protection against predators and a source of water to the chameleon. In studies on Madagascar’s chameleons within forests adjacent to riparian habitats, it was found that chameleons occurred at intervals in high densities (Jenkins et al., 2003). Chameleons are known to move to riparian habitats in times when survival resources are scarce especially during dry periods (Tolley & Herrel, 2014).
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Observations of mostly gravid adult C. dilepis females were made in the Acacia mearnsii woodland (habitat unit 3) and the Fadogia homblei-Burkea africana woodland (habitat unit 6).
In the Eragrostis curvula-Eragrostis gummiflua grassland (habitat unit 7) two adult C. dilepis that perched on isolated low growing Burkea africana shrubs were the only observations in this grassland. The Eragrostis curvula-Eragrostis gummiflua grassland (habitat unit 7) did not have a well-formed woody layer and provided less suitable perch plants for C. dilepis sub-adults and adults. This habitat has the lowest tree and shrub density and associated canopy cover of all the habitats but the second highest plant species diversity and plant species richness. The observations in this grassland habitat unit were made at the start of the active season in November 2016 and the second observation was at the end of the active season in May 2017. The Eragrostis curvula-Eragrostis gummiflua grasslands (habitat unit 7) rocky areas may be a preferred site during dormancy for C. dilepis. Timeframes of the observations of individuals found in this grassland coincide with first observations after dormancy and before the onset of dormancy.
5.2.3 Seasonality
Some of the variables that may affect the survival or dispersal of organisms on earth are temperature, moisture and food sources and they differ with the different seasons throughout the year (Drickamer et al., 2002). Activities of animals during different seasons centre around reproduction and food, therefore the presence and absences of many species could be associated with diapause or dormancy when these food resources become less or when a food source also goes into dormancy (Smith, 1977). The active periods in lizards may change when ecological circumstances change (Rose, 1981). In most lizards, it has been identified that environmental conditions could affect food supply, contribute to increasing and decreasing ambient temperatures and variation in photoperiods that may cause reptiles to go into or come out of dormancy (Etheridge et al., 1983). Lizards change their activity patterns in line with the environmental changes (Porter et al., 1973) and their activities are important for obtaining resources and successful reproduction when climatic conditions are favourable (Rose, 1981). Active periods are just as 133 important as the dormant periods in a lizard’s life cycle, inactivity may protect it from predation, it conserves energy when food is scarce that may prevent starvation and it will decrease dehydration during periods of drought (Rose, 1981).
The actual environmental stimuli that influence dormancy in lizards are not well known (Garrick, 1972). Different age classes have shown two main environmental variables that cause’s C. dilepis to be seasonal. The results of this study showed that rainfall influences the hatching times of C. dilepis and minimum temperatures drive presence and/or absence of C. dilepis sub-adults and adults. Hatching of C. dilepis eggs was started by the onset of the first summer rains. Wager (1983) observed that C. dilepis hatchlings would not be able to escape the nest chamber if the hardened soil is not sufficiently wet in order to make it easier to burrow upward and escape the nest. In other reptiles such as the Leopard tortoise (Geochelone pardalis), hatchlings can spend several weeks in the nest after hatching and wait for the first rains to appear (Patterson et al., 1989). The rain moistens the soil so that the Geochelone pardalis hatchlings can escape by digging to the surface through the softer wet soils (Patterson et al., 1989). In this study, seasonal hatching of eggs was strongly associated with rainfall. The time of the season when C. dilepis hatched and active periods of sub-adults and adults was also the time for the maximum biological activity of arthropods (Botha et al., 2016). C. dilepis is known to feed on a variety of flying insects but its main diet consists of grasshoppers (Branch, 1998; Tilbury, 2010). Some South African grasshopper species lay their eggs before the onset of the dry winter months in April where the eggs then enter a diapause of up to six months that hatch in the summer between November-February in the wet season (Bam, 2014). The laying and hatching of eggs of grasshoppers in South Africa (Bam, 2014) correspond mostly with the egg-laying and hatching timeframes of C. dilepis at Telperion. The habitat chosen by these arthropods to lay their eggs are generally associated with grasslands, cultivated lands and wooded grasslands (Bam, 2014) and corresponds to habitats where C. dilepis lay their eggs. In this study, these habitats have been found to be areas where hatchlings spend the first months of their life cycle. The grasshopper nymphs hatch and are small and wingless before their first instars (Bam, 2014). The grasshopper nymphs are suitable to the food prey-size requirements for newly hatched chameleons and will suit C. dilepis hatchlings better as a source of prey during the first months of their life cycles. 134
Adult and sub-adult C. dilepis’ presence, absence and seasonality at Telperion were affected by minimum temperatures but they were also active during the highest periods of insect activity. This study was unable to establish where the adult and sub-adult chameleons go during the unfavourable times of the year. C. dilepis may find shelter under a rock or within a hollow tree stump during its dormancy (Wager, 1983) or a dry sheltered place where it can spend winter months (Tolley & Herrel, 2014). The majority of reptiles in temperate zone habitats react to unfavourable climatic conditions by burrowing underground or using underground burrows as a refuge where it remains inactive during unsuitable climatic conditions (Bauwens, 1981). The advantage of this is that reptiles react toward these unsuitable conditions by brumating and it promotes survival (Bauwens, 1981). It is possible that C. dilepis may use burrows to brumate within by either digging it themselves or they may make use of existing animal burrows. There are numerous sizes of burrows made by smaller mammals in the habitat units at Telperion as described in the habitat descriptions of Chapter 3. These animal burrows are deeper than what a chameleon can generally dig. Etheridge et al. (1983) noted that deeper burrows used by reptiles during dormancy might act as a microhabitat that allows for cooler temperatures on warmer days but specifically warmer temperatures during colder periods, as would be expected because C. dilepis becomes dormant during colder periods.
Ectothermic animals such as reptiles and the insects that they feed on rely highly on environmental factors to control body temperatures (Rismiller & Heldmaier, 1988; Coggan et al., 2011). When seasons change the food availability in the form of insects may become less as insect become inactive with lower temperatures and shorter days during the dry season. As this happens the available food sources for C. dilepis to feed on will become less. The shortage of food and nutrition forces most lizards into dormancy (Bauwens, 1981) to rather utilise their stored fat reserves during winter (Avery, 1970). Brumation will benefit C. dilepis to rather use these reserves to survive the winter seasons during brumation and remain inactive instead of staying active and use its reserves without any available food sources to replenish these reserves. Lizards go into brumation when they have accumulated sufficient fat reserves to survive the winter dormancy period (Whitford & Creusere, 1977). It may be that sub-adults that enter their brumation use these fat reserves to continue its
135 growth during its dormancy and it may emerge as an adult, but this was not observed or testedand studies on this aspect of a chameleon’s life are not available.
In this study, the environmental data showed that minimum temperatures caused sub-adult and adult C. dilepis to enter or come out of brumation. It has been found for reptiles that occur in temperate zones the day lengths is a reliable constraint for lizard activity (Rismiller & Heldmaier, 1988), but since most reptiles spend their dormancy underground or within a shelter, where no or little light can be detected, this variable is usually ruled out in terms of spring emergence (Rismiller & Heldmaier, 1988). The results in this study based on the environmental data indicated that C. dilepis reacts to minimum temperature and precipitation to enter its dormancy and/or become active. This suggests that C. dilepis spends their dormancy in an area where the chameleon may notice these climatic changes.
5.3 ANECDOTAL DATA AND OBSERVATIONS
When travelling from one study plot to another, many chameleons were found perching on vegetation close to the roads and open areas where vegetation has been cleared recently. Although not recorded as part of the study their locations were noted. Open areas such as ecotones or areas where recent clearing of vegetation and where trees had recently fallen to create clearings have been found to be preferred perch sites for forest-dwelling chameleons (Tolley & Herrel, 2014). The suggestion is that the clearings created by the above disturbances create a suitable habitat for insects and thus abundance in food items for chameleons (Tolley & Herrel, 2014).
Personal observations in February 2017 noted a C. dilepis female constructing a nest and laying her eggs in open grassland next to an inactive termite mound. The nest was excavated using the front feet and pushing the soils out of the hole using the hind feet (Brian, 1961; Wager, 1983; Burrage 1972). The colouration of the female was yellow/green with orange/yellow spots, which has also been documented by Brain (1961) (Figure 5.2).
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Figure: 5.2: A female C. dilepis excavating a nest site to oviposit during the study period. Photo by Ishmael Matomane, 2017
The female C. dilepis was located for two consecutive nights perching in the same tree close to the nest site after laying her eggs. Wager (1983) noted that C. dilepis may perch in a nearby bush when egg laying is not incomplete by nightfall. It may have been that the female did not complete the egg laying and remained close to the nest site. The area where the excavation was made was covered with grasses and plant material so that it was inconspicuous and if the female was not noticed during nest construction the location of such a nest site would never have been noticed. The nest site was visited again 12 months later in late February 2018. Five C. dilepis hatchlings were located perching on grasses around the nest site.
In certain cases, I would find females covered in mud from recently digging a nest (Figure 5.3) (Tolley & Burger, 2007) and as Wager (1983) found these females were emaciated and thin and others would be in good condition.
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Dry mud from nest digging on the body
Figure 5.3: A female C. dilepis with mud on the body from nest excavation and laying eggs March 2017. Photo by T. L. O’Donoghue
C. dilepis would show signs of aggression during handling but would rarely follow through or bite, however, in younger chameleons stress was typically recorded with black colouration and not releasing of the plant that they were perched. Reactions varied between individuals but in some cases, there was severe aggression and a sudden lethargic reaction afterwards. On one occasion while trying to measure a hatchling it turned black. Brain (1961) found that when threatened, a young C. dilepis will feign death and fall from its perch turn black and curl up with its eyes closed until the perceived threat was no longer present. This colour change behaviour corresponds with Figure 5.4.
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Figure 5.4: A hatchling C. dilepis showing black colouration as an indication of stress during measuring and handling. Photo by T. L. O’Donoghue
5.4 CONCLUSION
Different factors affect the existence of C. dilepis at Telperion. Their life cycles may be affected by habitat structure, the plant species richness and diversity on food availability, soil texture and moisture during incubation and nesting, temperature and rainfall during hatching and coming out of dormancy. The habitats within which C. dilepis were located are all assumed suitable at one stage of its lifetime except where no C. dilepis were observed. Certain traits within the habitats utilised by C. dilepis hold definite advantages to one age class that is either negligible to another age class or it may become detrimental and it has either contributed to its presence or when it becomes unsuitable, contributing to its dispersal.
Female-biased sexual size dimorphism of C. dilepis at Telperion ensures that the female produces a greater clutch size, similar to lizards where female body size exceeds the size in males the productiveness is positively correlated to maternal body size (Shine, 1988; Cox et al., 2007; Stephens & Wiens, 2009; Pincheira- Donoso & Tregenza, 2011). The highly variable environmental and seasonal conditions as well as numerous predators may have contributed to C. dilepis females
139 evolving their body size for a high egg production. This ensures high numbers of eggs produced to promote higher hatchling survival at Telperion.
The location of most nest sites and observations of hatchling in different habitats with similar characteristics such as flat to mild sloped terrain, sandier soil texture and high shrub canopy cover for nest construction suggests that female C. dilepis prefer habitats with specific charactersitics on Telperion. If it is possible for females to detect the soil moisture content at the time they construct their nests is a subject for further study, but it may suggest that the fluctuation of the soil moisture levels during different times of the year goes unnoticed or it varies annually. The results of this study may also have indicated that the eggs in the soil where the female have chosen a nest site are protected by unforeseen treats such as seasonal or incidental fires.
It can be concluded that the observations of lesser hatchlings and more sub-adults in woodland habitats with higher plant density and diversity at Telperion suggests that C. dilepis grow to become a sub–adult and move to more suitable habitat units to suit its dietary requirements and its developing morphology. Vegetation that was once suited to young chameleons in a specific habitat unit, is now better suited for a growing or adult chameleon in a different habitat unit because of its structural differences (Keren-Rotem et al., 2006). The vegetation structure of smaller shrubs and grasses in habitat units utilised as a hatchling is not adequately suitable for perching or as a result of the perch plants not being robust enough to support the weight of growing hatchling chameleons into sub-adults. If chameleons cannot perch, the protection and shelter to avoid predators in open woodland and grassland habitats becomes insufficient due to the increase in body size as they grow. The low number of sub-adult and adult C. dilepis observed within the homogenous habitat units with low plant species diversity is an indication that C. dilepis moves to more plant diverse habitat units.
In the habitats, described resources in terms of food, vegetation structure, soils and moisture may become less or unavailable due to changes in the season and over time. This caused C. dilepis to adapt to the changing environment by adjusting its seasonal habits to suit the fluctuations in these resources. If C. dilepis did not adapt 140 to unsuitable environmental changes, dispersed within or between suitable habitats and periodically suitable habitats it may die. The time of activity is also crucial to reproduction efforts and laying of eggs. Even the eggs have adapted to an embryonic diapause and that the eggs themselves show seasonal behaviour to only start development once temperatures and environmental conditions are favourable only hatching after 12 months.
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CHAPTER 6 – CONCLUSION AND RECOMMENDATIONS
6.1 CONCLUSION
The main objectives this study adressed were to investigate habitat utilisation, seasonal distribution, dispersal and activity patternsand sexual dimorphism of C. dilepis at Telperion. It is the first study to be conducted on the biology of C. dilepis on Telperion. The results of this study will contribute to our knowledge and understanding of the resource and habitat requirements of the species. This study highlights important ecological aspects on the ecology of chameleons (C. dilepis) in the grassland biome. The results of this study will be incorporated into the reptile database of the Mpumalanga Tourism and Parks Agency (MPTA). C. dilepis was the only chameleon species observed at Telperion during the study.
The different habitat units within which C. dilepis occur have been successfully described in terms of species composition and structure. The variation in biotic and abiotic characteristics of the different habitat units of Telperion provides suitable conditions for the survival of C. dilepis. Chameleons were found to utilise the different habitat units disproportionately to the availability influenced by structural differences between habitat units. The results showed that the life cycle stage, distribution and therefore habitat utilisation is seasonally dependant. Definite sexual dimorphism was found in adult chameleons. The results of this study may assist land managers when considering reptiles in wildlife management plans.
6.2 MANAGEMENT RECOMMENDATIONS
The seasonal behaviour of C. dilepis should be considered when planning vegetation management strategies on Telperion. Management plans should consider strategies to accommodate the time of year when chameleons are most vulnerable such as during hatching and juvenile stages when they are prevalent in grassland habitas.
Some secondary roads occur in habitat units on Telperion that the emerging C. dilepis hatchlings prefer. Cutting grass along these secondary roads during times of
149 the year when hatchlings are prevalent in these habitat units may affect or kill hatchlings. It is recommended that where possible cutting could commence before the first rainfall. In addition, areas to be cleared of woody alien vegetation should occur at the times of year when chameleons are dormant.
6.3 RECOMMENDATIONS FOR FURTHER STUDY
More studies are required on the growth rates of C. dilepis. During this study there were some inconclusive indications of fast growth rates but unless individuals can be marked and tracked it cannot be scientifically proven.
Water availability, reproduction, perching sites, dormancy during winter, foraging and microhabitat use is suggested to influence chameleon ecology, but require more detailed investigations and further studies.
It is recommended that based on the observations of this study that researchers should not handle chameleons if ambient temperatures drop below 10°C due to slow recovery after handling and reluctance to perch.
6.4 SHORTFALLS AND LIMITATIONS TO THE STUDY
During March the temperatures dropped to below 10oC and at one stage according to the temperature loggers, it was 7oC. One individual measured and weighed during such a cold night responded lethargically and would not perch again. The response seemed to be due to colder outside temperatures. It was decided to only measure the perch height of the remaining specimens found due to colder temperatures. Although the research was of importance, the wellbeing of the animal was always considered first.
Because the chameleon hatchlings were not tagged due to their small size specific individuals could not be tracked through their life stages. Therefore the dispersal and movement between habitats could not be monitored on an individual basis.
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ANNEXURE A
List of plant species identified in the habitat units on Telperion during the study period Trees and Shrubs Family Plant Name Lannea discolor Lannea edulis Ozoroa paniculosa Searsia leptodictya ANACARDIACEAE Searsia magalismontana Searsia pyroides Searsia zeyheri Searsia gerrardii APOCYNACEAE Ancylobotrys capensis ARALIACEAE Cussonia paniculata Brachylaena discolor ASTERACEAE Brachylaena rotundata Gymnosporia heterophylla Gymnosporia tenuispina CELASTRACEAE Maytenus undata Gymnosporia heterophylla Terminalia brachystemma Combretum erythrophyllum COMBRETACEAE Combretum moggii Combretum molle Terminalia sericea Diospyros lycioides Diospyros whyteana EBENACEAE Euclea crispa Euclea linearis Euclea natalensis EUPHORBIACEAE Croton gratissimus Senegalia caffra Vachellia erioloba Vachellia karroo Vachellia robusta FABACEAE Burkea africana Elephantorrhiza burkei Rhynchosia nitens Mundulea sericea
HETEROPYXIDACEAE Heteropyxis natalensis Strychnos pungens LOGANIACEAE Strychnos cocculoides Tapinanthus species MALVACEAE Dombeya rotundifolia Ficus abutilifolia MORACEAE Ficus ingens Ochna pretoriensis OCHNACEAE Ochna pulchra OLACACEAE Ximenia caffra OLEACEAE Olea capensis Faurea saligna PROTEACEAE Protea caffra Protea welwitschii RHAMNACEAE Ziziphus mucronata Afrocanthium gilfillanii Aafrocanthium mundianum RUBIACEAE Pavetta zeyheri Vangueria infausta Vangueria parvifolia Toddaliopsis bremekampii RUTACEAE Zanthoxylum capense SALICACEAE Dovyalis zeyheri SAPINDACEAE Pappea capensis Englerophytum magalismontanum SAPOTACEAE Mimusops zeyheri SCROPHULARIACEAE Buddleja salviifolia STILBACEAE Nuxia congesta ULMACEAE Celtis africana VITACEAE Rhoicissus tridentata ZAMIACEAE Encephalartos lanatus Grasses Family Plant name Alloteropsis semialata Andropogon appendiculatus Andropogon eucomus Andropogon eucomus Andropogon huillensis POACEAE Andropogon schirensis Aristida adscensionis Aristida congesta Aristida congesta s. barbicollis Aristida congesta s. congesta
Aristida junciformis Aristida meridionalis Aristida scabrivalvis Aristida stipitata Aristida transvaalensis Brachiaria brizantha Brachiaria nigropedata Brachiaria serrata Chloris gayana Cymbopogon excavatus Cymbopogon plurinodis Cynodon dactylon Dactyloctenium aegyptium Digitaria brazzae Digitaria eriantha Digitaria monodactyla Diheteropogon amplectens Elionurus muticus Enneapogon cenchroides Eragrostis biflora Eragrostis capensis Eragrostis chloromelas Eragrostis curvula Eragrostis gummiflua Eragrostis heteromera Eragrostis inamoena Eragrostis lehmanniana Eragrostis nindensis Eragrostis plana Eragrostis racemosa Eragrostis rigidior Eragrostis superba Harpochloa falx Heteropogon contortus Hyparrhenia filipendula v. filipend Hyparrhenia hirta Hyparrhenia tamba Hyperthelia dissoluta Imperata cylindrica Ischaemum fasciculatum Loudetia simplex Melinis nerviglumis Melinis repens
Microchloa caffra Miscanthus junceus Monocymbium ceresiiforme Panicum maximum Panicum natalense Paspalum dilatatum Paspalum urvillei Pennisetum macrourum Pennisetum thunbergii Perotis patens Phragmites australis Phragmites mauritianus Pogonarthria squarrosa Schizachyrium jeffreysii Schizachyrium sanguineum Setaria lindenbergiana Setaria sphacelata Setaria sphacelata v. sphacelata Sporobolus africanus Sporobolus pyramidalis Themeda triandra Trachypogon spicatus Tricholaena monachne Trichoneura grandiglumis Triraphis schinzii Tristachya leucothrix Tristachya rehmannii Urelytrum agropyroides Forbs Family Plant Name Blepharis integrifolia Crabbea acaulis Crabbea angustifolia ACANTHACEAE Crabbea hirsuta Ruellia cordata Thunbergia atriplicifolia AIZOACEAE Delosperma cooperi AMARANTHACEAE Kyphocarpa angustifolia Cryptolepis oblongifolia Gomphocarpus fruticosus APOCYNACEAE Gomphocarpus glaucophyllus Pentarrhinum insipidum Raphionacme hirsuta
Raphionacme zeyheri Brachystelma rubellum Asparagus africanus ASPARAGACEAE Asparagus laricinus Asparagus suaveolens Nidorella podocephala Dicoma anomala Felicia muricata Gerbera jamesonii Helichrysum crispum Helichrysum epapposum Helichrysum kraussii Helichrysum miconiifolium Helichrysum nudifolium Helichrysum retortum Helichrysum rugulosum Helichrysum setosum Hermannia lancifolia Lactuca inermis ASTERACEAE Lopholaena coriifolia Nidorella anomala Nidorella hottentotica Oldenlandia herbacea Phymaspermum athanasioides Senecio barbertonicus Senecio coronatus Senecio gregatus Senecio oxyriifolius Sonchus dregeanus Sonchus nanus Stoebe vulgaris Hilliardiella oligocephala Polydora poskeana Cleome hirta Cleome maculata BRASSICACEAE Cleome monophylla Cleome rubella Dianthus mooiensis CARYOPHYLLACEAE Dianthus zeyheri Pollichia campestris CELASTRACEAE Salacia rehmannii COMMELINACEAE Commelina africana
Commelina erecta Cyanotis lapidosa Cyanotis speciosa Floscopa glomerata Kalanchoe paniculata CRASSULACEAE Kalanchoe thyrsiflora Cucumis africanus CUCURBITACEAE Momordica balsamina Bulbostylis burchellii Bulbostylis hispidula Carex rhodesiaca Coleochloa setifera CYPERACEAE Cyperus obtusiflorus Kyllinga alba Mariscus congestus Schoenoplectus corymbosus DENNSTAEDTIACEAE Pteridium aquilinum DICHAPETALACEAE Dichapetalum cymosum DIPSACACEAE Scabiosa columbaria EUPHORBIACEAE Dalechampia capensis Chamaecrista comosa Chamaecrista mimosoides Eriosema burkei Eriosema cordatum Eriosema salignum Indigofera comosa Indigofera cryptantha Indigofera daleoides Indigofera hedyantha Indigofera lupatana Indigofera melanadenia FABACEAE Indigofera sessilifolia Listia heterophylla Neorautanenia ficifolia Pearsonia sessilifolia Rhynchosia minima Rhynchosia monophylla Rhynchosia totta Sesbania sesban Sphenostylis angustifolia Tephrosia capensis Tephrosia longipes
Tephrosia lupinifolia GERANIACEAE Monsonia angustifolia HYACINTHACEAE Merwilla plumbea HYPERICACEAE Hypericum lalandii Acrotome inflata Leonotis ocymifolia Mentha aquatica LAMIACEAE Mentha longifolia Plectranthus madagascariensis Plectranthus species LENTIBULARIACEAE Utricularia species LOBELIACEAE Monopsis decipiens MALPIGHIACEAE Sphedamnocarpus pruriens Hermannia transvaalensis Hibiscus cannabinus Hibiscus microcarpus MALVACEAE Pavonia transvaalensis Sida alba Sida cordifolia Triumfetta sonderi MARSILEACEAE Marsilea species MOLLUGINACEAE Limeum viscosum MYRICACEAE Morella serrata MYROTHAMNACEAE Myrothamnus flabellifolius Eulophia angolensis ORCHIDACEAE Habenaria epipactidea Buchnera simplex OROBANCHACEAE Buchnera reducta OXALIDACEAE Oxalis depressa Ceratotheca triloba PEDALIACEAE Dicerocaryum eriocarpum Sesamum triphyllum PHYLLANTHACEAE Phyllanthus parvulus Polygala uncinata POLYGALACEAE Polygala hottentotta PTERIDACEAE Pellaea calomelanos RANUNCULACEAE Clematis brachiata Fadogia homblei RUBIACEAE Kohautia amatymbica Pentanisia angustifolia Nemesia fruticans SCROPHULARIACEAE Zaluzianskya elongata
SELAGINELLACEAE Selaginella dregei Solanum lichtensteinii SOLANACEAE Solanum campylacanthum Lasiosiphon caffer THYMELAEACEAE Lasiosiphon sericocephalus VELLOZIACEAE Xerophyta retinervis Lantana rugosa VERBENACEAE Lippia javanica Lippia rehmannii VITACEAE Cyphostemma lanigerum ZYGOPHYLLACEAE Tribulus terrestris Geophytes and Geoxylic suffrutex Family Plant name Amaryllis species Ammocharis coranica Boophane disticha AMARYLLIDACEAE Crinum bulbispermum Haemanthus humilis Scadoxus puniceus ANACAMPSEROTACEAE Talinum caffrum ARACEAE Stylochiton natalensis CHRYSOBALANACEAE Parinari capensis CONVOLVULACEAE Ipomoea ommaneyi FABACEAE Elephantorrhiza elephantina GERANIACEAE Pelargonium luridum Albuca setosa HYACINTHACEAE Ledebouria ovalifolia Ledebouria revoluta Hypoxis hemerocallidea HYPOXIDACEAE Hypoxis iridifolia Hypoxis rigidula Gladiolus ecklonii IRIDACEAE Gladiolus elliotii Lapeirousia sandersonii Alien and Exotic palnts Family Achyranthes aspera Achyranthes aspera v. aspera AMARANTHACEAE Alternanthera pungens Chenopodium album Gomphrena celosioides APIACEAE Centella asiatica
Acanthospermum australe Bidens bipinnata Bidens pilosa Campuloclinium macrocephalum Conyza bonariensis ASTERACEAE Crepis species Pseudognaphalium luteo-album Schkuhria pinnata Tagetes minuta Zinnia peruviana BIGNONIACEAE Jacaranda mimosifolia CACTACEAE Opuntia ficus-indica Acacia mearnsii FABACEAE Sesbania punicea MALVACEAE Hibiscus trionum MELIACEAE Melia azedarach MYRTACEAE Eucalyptus camaldulensis PHYTOLACCACEAE Phytolacca octandra Persicaria lapathifolia POLYGONACEAE Persicaria senegalensis PORTULACACEAE Portulaca species RUBIACEAE Richardia brasiliensis Populus alba SALICACEAE Populus nigra Salix babylonica Solanum mauritianum SOLANACEAE Solanum sisymbrifolium Verbena bonariensis VERBENACEAE Verbena brasiliensis