Ph.D., Faculty of Science, University of the Witwatersrand, 2011 / The loss of global biodiversity is exacerbated by the problem of trying to conserve species whose biology is not understood. The conservation of African snakes provides a striking example of this problem as many species remain entirely enigmatic. If we are to effectively manage or conserve these species, then we need to begin to describe and quantify their ecology. This project aimed to increase the body of knowledge regarding the ecology of Bitis schneideri, an arid-adapted African viperid, and as such, provide the basis for an informed critical assessment of the conservation status of the species. The improved understanding of the ecology of B. schneideri will contribute to the emerging study of African snake ecology, allowing scientists to compare and contrast the ecology of African snakes with those from northern temperate systems on which most of the global understanding of snake ecology is based. Bitis schneideri is a species of very small-bodied viperids that grow rapidly and reach sexual maturity within the first two years. They are sexually dimorphic for several traits, and evidence suggests that fecundity selection has played an important role in shaping their morphology. Moreover, I suggest that the selective advantage of being able to bury into sandy substrates has resulted in the extreme body size displayed in the species. Bitis schneideri is diurnally active, a state that is probably a derived condition, as B. caudalis (the sister species to B. schneideri) is reported to be nocturnal. Additionally, B. schneideri shows seasonal variation in activity, with increased activity during the spring mating season. Activity during winter is reduced, but not absent, and appears to be governed by the availability of suitable environmental conditions. Activity in B. schneideri is limited at all temporal scales by environmental conditions. Radio-telemetry and mark-recapture analysis showed that B. schneideri is highly sedentary, moving between 0.8 ± 6.5 m.d-1 and 47.3 ± 3.9 m.d-1, inhabiting small homeranges ( : 0.85 ± 0.09 ha; : 0.10 ± 0.09 ha). Moreover, juveniles show limited dispersal that, when combined with sedentary adult behaviour, could result in vulnerability to fragmentation by limiting gene-flow. Population densities are high ( 8 ha-1) and survival is low (39% and 56% per annum) compared to viperids from other parts of the world. Additionally, juveniles have higher survival rates than adults. Small litter sizes imposed by small-bodies, and low survival, means that B. schneideri must reproduce frequently, probably annually, in order for populations to persist. Such frequent reproduction is atypical, even among closely related species, and in B. schneideri, appears to be facilitated through the capacity to feed year-round in the aseasonal habitat in which they occur. Bitis 6 schneideri is a generalist that ambushes prey in proportion to encounter frequency. Also, I show that the capacity of B. schneideri to capture and consume relatively large prey items provides snakes with a large energetic advantage. Abundant generalist predatory birds are likely to be more important predators of B. schneideri than are rare specialist predatory raptors, although snakes are also vulnerable to other predators that include small mammals, other reptiles, and large invertebrates. Small body-size has two important implications for B. schneideri biology – reduced litter size, and vulnerability to a wide suite of predators. These attributes interact to result in low survival, reduced movement and dispersal, frequent reproduction, generalist foraging, and year-round feeding. Bitis schneideri is not at significant risk of facing extinction in the near future. The primary biological factor that ameliorates against extinction risk is large population size and high population density.

Estuaries worldwide are being subjected to various degrees of catchment degradation, which is having severe consequences on the integrity of these aquatic ecosystems and their ability to function properly. This thesis investigated the relationship between catchment land-cover and estuarine health in four temporarily open/closed estuarine systems (TOCEs) in South Africa, namely the Groot Brak, East Kleinemonde, Mdloti and Tongati. GIS techniques were employed to delineate catchments, lower sections of catchments, 1 km and 100 m buffer zones, and to quantify the extent of land-cover classes present within these delineations. Anthropogenic activities outlined by the Department of Water Affairs and Forestry (DWAF) Resource Directed Measures (RDM) studies and their associated land-cover classes were described. The possible links between catchment and buffer zone land-cover class composition and health of the estuaries were explored. Results indicated that there was a relationship between catchment and estuarine health within the Coastal Protection Zone (CPZ) (1 km and 100 m) buffers, but not at a broader catchment level. Out of natural, urban built-up and cultivation land-cover classes, natural land was determined to be the best predictor of estuarine health within the CPZs. A method of rapidly assessing South African TOCE condition was applied and could be used to prioritise these estuaries for rehabilitation and/or conservation.

This report contains the results of some ecological and systematic studies on the diatoms from the Vaal Dam catchment area in the Transvaal, and the Bloukrans River in the Eastern Cape Province. In Part 1 the effects of high concentrations of nitrogen were studied in relation to the composition of the diatom associations. Water samples from four stations on the Bloukrans River were analysed chemically at certain intervals during the months of April and August 1967. Diatom samples collected from these stations at the beginning and end of each of these sampling periods were subjected to a "Thomasson Analysis" to determine the relative densities of the various species in the diatom associations. A statistical analysis of the results reflected a poor but positive correlation between the two variables, i.e. high numbers of nitrogen heterotrophic Nitzschiae were correlated with high concentrations of nitrogen, while low numbers were correlated with low concentrations. Part 2 presents the results of the ecological studies on the diatom associations of the Vaal Dam Catchment Area. In this section the diatom associations from each sampling point or station were subjected to a "Thomasson Analysis" to determine the relative densities of the different species in the associations. Employing already known correlations between environment and association, the results of this analysis were discussed and the ecological conditions for each sampling station were assessed. The associations were similar in composition over the entire catchment area, and indicated on the whole water of good quality. Points of pollution were detected, but were generally localised and the effects of the pollution were soon removed. Only the Waterval River showed evidence of more constant pollution. The associations provided evidence for some seasonal variation in their composition. Finally in Part 3 the systematics and taxonomy of the diatoms in the Vaal Dam catchment area are discussed. References are made to the original and more recent descriptions of each species found in this study, and a list of synonyms is given wherever 'possible. Comments on the systematics, taxonomy and autecology of each species are given, and the distribution of the species in South Africa and the Vaal Dam catchment area is discussed. A number of species, varieties and forms have been recorded for the first time in South Africa. During the course of this study 20 species have been described as new to science; the descriptions of some have been published, while the descriptions of the others will be published formally in the future. All species described as new or having interesting features are illustrated in the plates.

There is a paucity of published information on fish utilization of salt marshes outside North America. This dissertation represents the first intensive examination of the ichthyofauna associated with salt marshes in southern Africa and examines the species composition, diversity, size structure, distribution and estuarine dependence of fishes that utilize salt marshes in the Kariega Estuary. The research was concentrated on Taylor's salt marsh, with comparative studies being conducted on other salt marshes and habitats within the marine dominated Kariega Estuary. The possible importance of salt marshes as feeding and refuge areas for fishes was examined, as was the role of salt marshes in the food web of the estuary. The fishes frequenting salt marshes in the Kariega Estuary were predominantly the juveniles of marine species, with Mugilidae being the dominant family. The ichthyofauna was distributed primarily in the intertidal creeks with very few specimens captured on the vegetated Spartina maritima and Sarcocomia perennis flats. The different reaches of the intertidal creek were characterised by distinct fish assemblages. The fish assemblages associated with the intertidal salt marsh creeks were significantly different from those found in the eelgrass beds, the other dominant intertidal habitat in the Kariega Estuary. The eelgrass beds were dominated by estuarine fish species and had a higher density and standing stock of fishes when compared to the salt marsh creeks. The diversity of fishes in the two habitats was however similar. The intertidal salt marsh creek ichthyofauna also differed significantly from that found in the main estuary channel. The creek ichthyofauna was dominated by 0+ juveniles while the main channel had many subadult and adult fishes. The channel habitat also had numerous large piscivorous fishes which were absent from the salt marsh creeks. The low number of piscivorous fishes, together with limited fish predation from other sources, may be the reason why salt marshes provide a refuge for juvenile fishes that frequent these habitats. Unlike previous studies on North American, Australian and European salt marshes, the dominant fish species that frequented Taylor's marsh were not recorded feeding extensively on the marsh, and those that did had a limited distribution. The role of fishes in the transfer of energy off the Kariega salt marshes is therefore likely to be minimal. A stable carbon isotope study on the dominant primary producers and consumers within the Kariega Estuary revealed that detritus originating from the high lying salt marsh plants Sarcocornia perennis and Chenolea diffusa was not utilized by fishes in the Kariega Estuary. Preliminary results indicated that the cord grass Spartina maritima may be an important energy source to the fishes in the Kariega Estuary, but further research is needed to confirm this.

M.Sc. (Aquatic Health) / Urban impoundments play both a recreational and functional role in the urban areas. From the recreational point of view these impoundments offer aesthetically pleasing environs as well as habitat for aquatic organisms in a built environment. The functional role of impoundments is related to attenuation of storm water run-off that is released into urban water courses. Storm water run-off can have adverse effects on the ecological integrity of aquatic ecosystems. Water quality will influence other physical and biological components of these systems. It is for this reason that the ecological health of impoundments is assessed from an ecotoxicological perspective, focusing on Westdene and Emmarentia dams in Johannesburg. It has become common practice to use aquatic biota to assess the impacts of human activities on aquatic ecosystems. This is because animals and plants can provide a long-term integrated reflection of water quality, quantity, habitat quality and other environmental conditions. Water and sediment quality were assessed by applying standard techniques and protocols. Fish were utilized as bioindicator organisms in order to quantify the concentrations of metals available in the dam. Abundance of the macro invertebrate community was also measured. Physico-chemical water analyses were done during each sampling period to assess the water quality against the South African Water Quality Guidelines. Ammonia, which can be toxic to aquatic life, remained high in both dams. High phosphate concentration during the low rainfall season in Westdene Dam could result in eutrophication related problems. The microbiological analysis of the water suggests that the main cause of faecal and total coliforms contamination of the impoundments possibly originates from dominant birds, African Sacred Ibis (Threskiornis v aethiopicus) and Egyptian Goose (Alopochen aegyptiaca ) in the dam and others water birds frequenting the dams. Abnormally high concentrations of the heavy metals Nickel and Chromium were found in the water body and fish (Clarias gariepinus and Tilapia sparmanii ) thus indicating bioavailabity of these metals resulting in bioaccumulation in fish. High concentration of Lead in sediment was recorded and may greatly impact benthic macroinvertebrates population and their habitat.

Rhenosterbos, Elytropappus rhinocerotis (L.f.) Less belongs to a purely South African section ot the Compositae. It is restricted to an area of low rainfall which is evenly distributed over the year. The plant is a specialised xerophyte with minute leaves and white pubescent twiglets. Older stems become woody and dry and bear no leaves. The shrubs have a life span of about eight years; the plants are most succulent and luxurious during the third and fourth year, after which they tend to become woody and scraggly. For this investigation insect material was obtained by sweep-net collection and field observation. In the Grahamatown district 78 collections were made during the period March - November 1953, with data thus obtained being embodied in this work. In addition to this, collections were made in the Cradock-Hofmeyer, Uitenhage, Riversdale, Bot River, Swellendam and Stellenbosch districts. Twenty species of insects have been shown definitely to feed on the plant and there are another 13 which probably feed on it. Of the 20 species attached to the plant, 12 are sucking forms belonging to the Orders Homoptera and Hemipters. They include six Coccids, two Jassids a Cercopid, two Mirids and a Pentstomid. The Coleoptera are represented by one or perhaps two species which feed on the plant. The Lepidoptera are represented by two important species of moth, a Geometrid and a Pyralid. Four species of gall forming Diptera are associated with the plant. There are two species of Trypetidae which are responsible for piriform swellings of growth points and are distributed evenly throughout the bush. There are also two Cecidomyidae one of which develops in the growth points of the shoots and is responsible tor a minute tubular gall. The other develops in a fusiform stem gall. This latter gall has been shown to be more common on smaller bushes than on larger ones, implying that the adult female may show certain selective powers during oviposition. The size of the insect population is held in check by spiders mantids and other general predators. There are several Coccinellids which prey on the scale insects. Rhenosterbos supports a small, well regulated community of insects. The balance between plant and animal is very dellcate because of the high degree of specialisation of the plant. On occasions this balance has been known to break down, and the insects present in abundance have swamped and killed large patches of the plant.

Until recently most sandy beach studies have made use of snapshot samples but the validity of this approach has been widely questioned. In this study we attempt to resolve this issue by repeatedly sampling two beaches using a stratified random design. Three sampling sessions took place, each approximately six months apart. The three sites on the first beach were selected according to the type of beach (reflective, intermediate and dissipative) with each morphological type duplicated on the second beach. Many of the physical variables measured had significant differences between the sampling sessions but only a few were significantly different between the Sites. Very few of the individual physical variables had significant relationships with the sandy beach macrofaunal abundance and density. However, composite indices had a greater number of significant relationships with the macrofaunal abundance and density. Also very few significant relationships were seen between the species richness and the physical variables of the beaches studied. Effluent line crossing frequency was the only physical variable that could predict species richness but it was considered a weak predictor. Changes in the zonation patterns within and between beaches were also investigated. The highest concentration of taxa and individuals was found near the low-water mark with a gradual reduction of both towards the high-water mark. Some of the sandy beach community variables (abundance, density and species richness) showed significant difference between the sampling sessions but no significant differences were seen between the two beaches. The presence of three zones was noted using MDS plots and Cluster diagrams. However, using a SIMPER analyses, four zones with the possibility of a fifth was noted.

This study aims at explaining the distribution and composition of the southern Cape forests, the largest forest complex in southern Africa. These are the only forests in southern Africa which are actively and scientifically managed for their products and values. Population growth due to forestry, agricultural and economic development and a growing tourism industry exerts increasing pressures on the natural environment of the southern Cape coast and therefore affect the dynamics and conservation of the forests. Conservation and sustained utilization of the forests require a sound knowledge of the composition, structure and dynamics of the forests. This study was aimed at an understanding of the biogeography of the forests at the landscape level in order to isolate those variables which contributed to the present distribution and composition of the forests. Determinants of the forest location pattern in the southern Cape were identified as rainfall above 500 mm, which determines the potential limits of the forests, and the bergwind fire pattern, which determines the actual forest distribution. Fires driven by the hot, dry, northwesterly, föhnlike bergwinds interacted with the terrain physiography since prehistorical times and the forests persisted in topographic shadow areas. The largest forests in the area therefore occur on the coastal platform at the foot of the mountains, in the river valleys and on the coastal scarp. Forests in the mountains, with high rainfall, are small and scattered. The results have shown that the bergwind driven fires control the distribution of forests which have important implications for the understanding of forest dynamics and for conservation management of forests in multiple-use management systems. Forest composition at the landscape level was studied by means of plant species lists. A species list for the southern Cape forests was annotated with information on the growth form, breeding system, propagule type, forest type, moisture tolerance, abundance and spread in the study area, and the distribution range in southern Africa, of each species. Analyses of the list showed that the species/family ratios for the southern Cape forest flora are very low, that woody plants have mostly fleshy propagules and herbaceous plants mostly dry propagules, and that several species have adaptations to adverse conditions. The species richness and composition, and floristic similarity and relationships were compared between the southern Cape forest flora and the floras of 13 other forests representing particular geographic regions in southern Africa. Forest size explained relatively little of the variation in species richness of the forests. Stepwise multiple regression analyses indicated that the number of dispersal corridors, the proximity to other forests and mean altitude explained most of the variation in number of woody species, whereas the number of landscape types and dispersal corridors explained most of the variation in number of herbaceous species. The high similarity between the southern Cape forest flora and those of the forests along the escarpment from the eastern Cape to northern Transvaal, and the southern attenuation of species suggest that the forests were once continuous. It is suggested that the Sundays river valley east of Port Elizabeth isolated the southern Cape forests from those to the east already during the Pliocene or earlier.

The three Pycnonotus bulbuls endemic to Africa, P. barbatus, P. nigricans and P. capensis, occupy mutually exclusive distributions in southern Africa. These species are closely related and appear to occupy very similar ecological niches, only in different regions. Using a multifaceted approach, this study attempts to explain the ecology of this species complex. All three species show similar physiological responses to temperature extremes, and are therefore unlikely to be directly limited by environmental temperature. However, their distributions are highly correlated to a complex of environmental variables, particularly winter minimum temperatures, the coefficient of variation in mean annual rainfall, and the seasonality of rainfall. This combination of environmental parameters can be used to predict the distributions of at least one of the species, P. nigricans, accurately. An analysis of the vocalizations and behaviour of the three species revealed that, whilst P. capensis has a number of recognizably different vocalizations, those of P. barbatus and P. nigricans are very similar. The three have nearly identical behaviours, particularly courtship and pre-copulatory behaviours. The mate recognition systems of the three are therefore extremely similar. P. barbatus is territorial during the breeding season, and exhibits highly structured-variation in male territorial song at the level of the local neighbourhood. The literature pertaining to song dialects is reviewed, and a new hypothesis is postulated to explain song-matching in terms of neighbour/stranger discrimination and the possible existence of cooperative territory defence. A survey of the eastern Cape region, where all three species come into contact, showed that extensive hybridization is taking place between each species pair. Phenotypically, this hybridization is restricted to narrow hybrid zones, that are considered to be stable in both time and place. The evolutionary and ecological significance of these zones to the distributions of the species is discussed, and it is proposed that the zones are maintained by selection acting on differentially-adapted genomes along an environmental gradient.

Thesis (MSc)--University of Stellenbosch, 2001. / ENGLISH ABSTRACT: The foraging mode of the Cape grass lizard, Chamaesaura anguina, was determined by using three criteria: 1) the number of movements per minute (MPM) and the percentage of time spent moving (PTM) during periods of activity; 2) the amount of tongueflicking directed at cotton applicators labelled with prey chemicals as a measure of prey chemical discrimination; 3) the stomach contents of the lizards as an indication of the natural diet. Observations were made by means of binoculars from an observation tower using a seminatural outdoor enclosure, and through a one-way glass panel using a seminatural indoor enclosure. Each lizard was observed for aIO minute period during peak activity and the times it was moving and the times it was stationary were recorded. Data obtained in the indoor- and outdoor enclosures did not differ significantly and were pooled. "MPM(0.37 ± 0.21 SD) and PTM (1.92 % ± 0.93 SD) values recorded for C. anguina (N = 10) fall within the range given as characteristic for sit-and-wait foragers. Nine C. anguina individuals were habituated in glass terraria to accept mealworms offered to them. When all lizards accepted food without hesitation, they were tested for their ability to discriminate among three different odours presented to them in a randomized block design: prey odours consisting of mealworm surface odours, distilled water as an odourless control stimulus, and cologne as a pungency control. The number of tongue-flicks directed at the cotton applicator containing the stimulus odour during 60 s was recorded. No statistically significant differences were found among the responses to the three treatment odours (Kruskal-Wallis, H = 2.41, dj = 2, P = 0.30). An analysis of the stomach contents of21 C. anguina specimens revealed a diet of mostly diurnally active arthropod prey species. The preferred body temperatures selected by 12 grass lizards in a thermal gradient were measured six times during a 48 hour period, using a copper-constantan thermocouple inserted into the cloaca. The measured body temperatures (N = 72) ranged from 22.62 oe - 27.07 oe with a mean of24.82 oe ± 2.27 SD. The low preferred body temperature exhibited by C. anguina as compared to other cordylids may be attributed to the combined influence of vegetative cover, high altitude, and high surface-volume ratio. To determine movement patterns and microhabitat use, six lizards were observed in a seminatural outdoor enclosure (4 x 4 m). The location of the grass tufts in the enclosure was mapped, and the position of each lizard within the enclosure was noted on 17 mornings. Observations of lizard behaviour during periods of activity were made by means of binoculars from an observation tower. Although C. anguina did not show reliance on a specific shelter site, the taller, broader tufts were generally preferred as refuges during inactivity. There were significant differences between the heights (student's z-test; P < 0.001) and the diameters (Mann-Whitney; P < O.00 1) of the preferred grass tufts, and those grass tufts that were not preferred as refuges, respectively. The lizards usually sheltered in a coiled-up position in the middle of the grass tufts close to the ground. During active periods, the lizards perched in an elevated position in the vegetation by entangling their elongated bodies and tails in the grass for efficient weight distribution. Locomotion was mainly restricted to the strike action when attacking prey. Fynbos and grassland, which are the main habitat of grass lizards of the genus Chamaesaura, are fire-prone. With their serpentiform morphology, grass lizards differ markedly from other cordylids, the majority of which are rock-dwelling. One aim of this study was to determine whether grass lizards make use of refuges like burrows or crevices within their grasslrestioid habitat during periods of inactivity or when threatened by fire. Refuge selection during inactivity was determined experimentally. Twelve lizards were offered different refuge options, namely grass tufts, crevices, burrows and loose sand. All twelve lizards preferred to shelter in the grass tufts. When the grass tufts were removed, only two lizards made use of the burrows and crevices provided, the other 10 not sheltering at all. Refuge selection when threatened by fire was tested by placing the 12 lizards in an enclosure provided with grass tufts and two types of refuges, burrows and crevices. The grass was set alight at one end of the enclosure and the fire was fanned on towards the other end with the aid of a high-speed fan. Precautions were taken to ensure the safety of all the lizards and to intervene when they were in direct danger. Only two of the 12 lizards sought shelter in the refuges provided. Of the remaining 10, six fled and four were trapped by the flames, requiring intervention. The results of these experiments, as well as field observations, suggest that C. anguina seldom makes use of shelter options other than grass and restio tufts, even when threatened by fire. In the case of fire, it flees by 'grass-swimming'. Field observations also suggest that mortality during and after a fire is considerably higher than in the case of rock-dwelling cordylids. The reproductive status of adult females (N = 85) were determined on the basis of the developmental stage of ovarian follicles and the presence or absence of oviductal eggs. Females were grouped into four reproductive categories: pre-vitellogenic, early vitellogenic, pre-ovulatory and gravid. To determine the reproductive cycle exhibited by the males (N = 46), testicular volume and seminiferous tube diameter were measured, as well as the spermatogenic activity assessed qualitatively. Spermatogenic activity was assessed by using Licht's (1967) classification system. The snout-vent length (SVL) of 144 specimens was measured. Sexual size dimorphism (SSD) recorded for C. anguina was quantified by a size dimorphism index (SDI). Reproductive activity was asynchronous among females, differing from the normal cordylid cycle of autumn/winter vitello genic activity, followed by winter/spring ovulation and gestation in late summer to autumn. The significant seasonal variation that existed in testes volume (ANOVA; F (7,22) = 3.70; P < 0.05) and seminiferous tubule diameter (ANOVA; F (10,25) = 4.90; P < 0.05), as well as sermatogenic activity as observed by histological examination, indicated that C. anguina males follow an annual spermatogenic cycle that can be described as post-nuptial. The cycle is characterized by summer/autumn spermiogenesis, associated with sperm storage throughout winter. Chamaesaura anguina males differ from other cordylids following a post-nuptial cycle, by starting with spermatogenesis in spring. The mean SVL of female grass lizards (109.51 mm ± 20.60 SD) was significantly larger (Mann-Whitney; P < 0.001) than that of males (84.77 mm ± 9.39 SD). A positive SDI of 1.29 and a SDImax of lAO were determined. Female-biased dimorphism in SVL recorded for C. anguina corresponds with the general pattern recorded for terrestrial cordylids, but contrasts with male-biased dimorphism in rupicolous forms. The longer SVL of C. anguina females facilitates higher fecundity. This, in turn, might be an adaptive survival strategy for this lizard species in the fire-prone environment where it occurs, because successful recruitment is facilitated by high fecundity. KEYWORDS: Chamaesaura anguina; serpentiform body; cryptic colouration; grass/restio habitats; undulatory locomotion; foraging mode; preferred body temperature; movement patterns; microhabitat use; fire susceptibility; refuge selection; reproductive cycle; sexual size dimorphism. 4 / AFRIKAANSE OPSOMMING: Die voedingswyse van Chamaesaura anguina is bepaal deur drie kriteria: 1) die getal bewegings per minuut (BPM) en die persentasie tyd wat aan beweging bestee word (PTB) tydens aktiewe periodes; 2) die hoeveelheid tongskiete wat gerig word na wattepluisies bedek met prooi chemikalieë as 'n maatstaf van prooi chemiese diskriminasie; 3) die maaginhoud van die akkedisse as 'n indikasie van hul natuurlike diëet. Waarnemings is met 'n verkyker vanaf 'n waarnemingstoring langs 'n buitemuurse kampie gemaak, terwyl dit deur 'n eenrigting glaspaneel in die geval van 'n binnemuurse opstelling gemaak is. Elke akkedis is vir 'n periode van 10 minute tydens piek-aktiwiteit dopgehou, en die tye wat dit beweeg het en nie beweeg het nie, is aangeteken. Data verkry in die binnemuurse - en buitemuurse opstellings het nie statisties van mekaar verskil nie en is saamgevoeg. BPM (0.37 ± 0.21 SD) en PTB (1.92 % ± 0.93 SD) waardes aangeteken vir C. anguina (N = 10) val binne die reeks waardes wat as kenmerkend vir sit-en-wag voeders beskou word. Nege C. anguina individue is in glas terraria gewoond gemaak om meelwurms te aanvaar wat hul aangebied is. Toe al die akkedisse die kos sonder huiwering aanvaar het, is hul vermoë getoets om tussen drie verskillende geure wat hul aangebied is in 'n ewekansige blokontwerp, te diskrimineer: prooigeur bestaande uit die reuk van meelwurms, gedistilleerde water as 'n geurlose kontrole stimulus, en reukwater as 'n skerp kontrole. Die hoeveelheid tongskiete gerig na die gegeurde wattepluisie gedurende 'n 60 s periode, is aangeteken. Geen statisties-beduidende verskille is gevind tussen die reaksies tot die drie geure nie (Kruskal-Wallis, H = 2.41, df= 2, P = 0.30). 'n Analise van die maaginhoude van 21 C. anguina individue het meestal dag-aktiewe arthropoda prooispesies onthul. Die voorkeur liggaamstemperature wat deur 12 akkedisse in 'n termiese gradiënt geselekteer is, is ses maal gemeet gedurende 'n 48 uur periode, deur van 'n termo-koppel wat in die kloaka geplaas is, gebruik te maak. Die bepaalde liggaamstemperature (N = 72) het gevariëer van 22.62 oe - 27.07 oe met 'n gemiddeld van 24.82 oe ± 2.27 SA. Die lae voorkeur liggaamstemperatuur van C. anguina mag dalk toegeskryf word aan die gekombineerde invloed van plantbedekkingskadu, hoë hoogte bo seevlak, en hoë oppervlakte-volume verhouding. Die bewegingspatrone en mikrohabitat-gebruik van C. anguina is bestudeer deur ses akkedisse in 'n buitemuurse kampie aan te hou. Die ligging van die graspolle binne die kampie is op 'n kaart aangeteken, en die posisie van elke akkedis binne in die kampie is op 17 oggende aangeteken. Verdere waarnemings is gemaak met 'n verkyker vanaf 'n waarnemingstoring terwyl die akkedisse aktief was. Alhoewel die C. anguina individue nie herhaaldelik 'n spesifieke skuilplek gebruik het nie, het hul die langer, breër graspolle as skuilplek gedurende onaktiwiteit verkies. Daar was 'n hoogs beduidende verskil tussen onderskeidelik die hoogtes (studente z-toets; P < 0.001) en die deursnitte (studente I-toets; P < 0.001) van die verkose graspolle, en die graspolle wat nie gekies is as skuilplekke nie. Hulle het gewoonlik in 'n opgerolde wyse, in die middel en na aan die bodem van die graspolle, geskuil. Daar is gevind dat C. anguina vanaf 'n verhewe posisie voed deur sy verlengde liggaam en stert in die grass te vervleg om doeltreffende gewigsverspreiding te verseker. Beweging was hoofsaaklik tot die vangaksie van prooi beperk. Vuur is 'n algemene verskynsel in fynbos en graslande, wat die hoof habitat van grasakkedisse van die genus Chamaesaura uitmaak. Met hulle slangagtige morfologie, verskil grasakkedisse drasties van ander lede van die Cordylidae, waarvan meeste rotsbewonend is. Die doelwit van hierdie studie was om te bepaal of die grasakkedisse gebruik sal maak van skuilplekke, soos gate en klipskeure binne die grashabitat, gedurende periodes van onaktiwiteit of wanneer bedreig word deur vuur. Twaalf akkedisse is verskillende skuilopsies aangebied, naamlik graspolle, klipskeure, gate en los sand. Al twaalf het verkies om in die graspolle te skuil. Toe die graspolle verwyder is, het slegs twee akkdisse die klipskeure en die gate benut, terwyl die ander 10 nie geskuil het nie. Skuilplek-seleksie wanneer bedreig word deur vuur, is getoets deur 12 akkedisse in In afskorting te plaas wat met graspolle en twee tipes skuilplekke, gate en klipskeure, voorsien is. Die gras aan die een kant van die afskorting is aan die brand gesteek en is aangehelp m.b.v. 'n hoë-spoed waaier. Voorsorgmaatreëls om die veiligheid van al die akkedisse te verseker en om in te gryp as hulle in direkte gevaar sou verkeer, is getref. In twee van die 12 gevalle het die akkedisse skuiling gesoek in die beskikbare skuilings. In die oorblywende 10 gevalle het ses akkedisse gevlug, terwyl vier deur die vlamme vasgevang was en daar ingegryp moes word. Die resultate van hierdie eksperimente, sowel as waarnemings wat in die veld gemaak is, dui daarop dat C. anguina selde van skuilopsies, anders as graspolle en restio's, gebruik maak as hulle deur vuur bedreig word. In die geval van vuur, vlug hulle deur te "swem" deur die gras. Veldwaarnemings dui ook daarop dat mortaliteit gedurende en na die vuur heelwat hoër is as in die geval van rotsbewonende gordelakkedisse. Die reproduktiewe status van volwasse wyfies (N = 85) is bepaal deur die ontwikkelingsfase van ovarium follikels te ondersoek en deur die teenwoordigheid of afwesigheid van eiers in die oviduk. Wyfies is in vier reproduktiewe kategorieë gegroepeer: pre-vitellogenies, vroeg vitellogenies, pre-ovulatories en dragtig. Testikulêre volume en saadbuisdeursnit is gemeet, en spermatogeniese aktiwiteite soos histologies vasgestel, is gebruik om die reproduktiewe siklus van die mannetjies (N = 46) te bepaal. Spermatogeniese aktiwiteit is bepaal deur van Licht (1976) se klassifikasie sisteem gebruik te maak. Die snoet-kloaak lengte (SKL) van 144 individue is gemeet en die seksuele grootte-dimorfisme (SGD) soos bepaal vir C. anguina, is gekwantifiseer deur middel van In grootte-dimorfisme-indeks (GDI). Voortplantingsaktiwiteit in die wyfies was nie gesinchroniseerd nie, en verskil dus van die normale gordelakkedissiklus met herfs/winter vitellogeniese aktiwiteit, winter/lente ovulasie en swangerskap in die volgende laat somer tot herfs. Die beduidende seisoenale verskil wat bestaan het in die testesvolume (ANOV A; F (7.22) = 3.70; P < 0.05) en die saadbuisdeursnit (ANOVA; F (10,25) = 4.90; P < 0.05), asook testis histologie, het aangedui dat C. anguina mannetjies 'n jaarlikse spermatogeniese siklus volg, beskryf as "post-nuptial". Hierdie siklus word gekenmerk deur somer/herfs spermiogenese, geassosieer met spermstoring gedurende die winter. In teenstelling met ander gordelakkedisse wat hierdie siklus volg, begin spermatogenese in C. anguina alreeds in die lente. Die gemiddelde SVL van die wyfies (109.51 mm ± 20.60 SA) was beduidend groter (Mann-Whitney; P < 0.001) as dié van die mannetjies (84.77 mm ± 9.39 SA). In Positiewe GDI van 1.29 en In GDImax van 1.40 is gemeet. Wyfie-plus dimorfisme in SKL bepaal vir C. anguina, stem ooreen met die algemene patroon waargeneem by terrestriële gordelakkedisse, maar is in kontras met mannetjie-plus dimorfisme by rotsbewonende vorme. Die langer SKL by wyfies van C. anguina kan In hoër fekunditeit fasiliteer. Dit mag dalk In oorlewingstrategie vir die species wees wat in In vuurgeteisterde omgewing voorkom, omdat suksesvolle rekolonisering deur In hoë fekunditeit aangehelp word. TREFWOORDE: Chamaesaura anguina, slangagtige liggaam; kriptiese kleuring; graslrestio habitatte; kronkel beweging; voedingsrnetode; voorkeurtemperatuur; bewegingspatrone; mikrohabitat-gebruik; vatbaarheid vir vuur; skuilplekseleksie; voortplantingsiklus; seksuele dimorfisme.