Doctor of Philosophy(PhD) / It is only in recent decades that marine scientific research has begun to reveal the true physical characteristics and resource potential of the open ocean and deep seabed beyond national jurisdiction. A combination of factors such as the depletion of inshore fish stocks and an increase in global maritime trade has led to greater usage of the vast maritime area beyond the territorial sea and exclusive economic zone limits of the coastal states. Human activities in this area of the ocean, which covers approximately 50% of the world’s surface, have expanded to include bioprospecting, exploration for deep seabed minerals, more sophisticated marine scientific research and deep sea tourism. This rise in human activities beyond the offshore zones of coastal states poses actual and potential threats to the physical characteristics and biodiversity of the open ocean and deep sea environments. Arbitrary human intrusions into this largely unexplored marine domain have the potential to harm the intricate links between complex marine ecosystems and to erode components of marine biodiversity. This thesis examines the global and regional provisions which have been put in place to regulate the environmental impacts of human activities that occur beyond national jurisdiction. An analysis of these instruments and their implementation reveals that the current international law framework provides only minimal levels of protection for the marine environment beyond national jurisdiction. It explores several options based on the 1982 United Nations Convention on the Law of the Sea (LOSC) and the 1992 Convention on Biological Diversity (CBD) to establish a cohesive environmental protection system for the marine environment beyond national jurisdiction.

Biodiversity is a concept that plays a key role in both scientific theories such as the species-area law and conservation politics. Currently, however, little agreement exists on how biodiversity should be defined, let alone measured. This has led to suggestions that biodiversity is not a metaphysically robust concept, with major implications for its usefulness in formulating scientific theories and making conservation decisions. A general discussion of biodiversity is presented, highlighting its application both in scientific and conservation contexts, its relationship with environmental ethics, and existing approaches to its measurement. To overcome the limitations of existing biodiversity concepts, a new concept of biocomplexity is proposed. This concept equates the biodiversity of any biological system with its effective complexity. Biocomplexity is shown to be the only feasible measure of biodiversity that captures the essential features desired of a general biodiversity concept. In particular, it is a well-defined, measurable and strongly intrinsic property of any biological system. Finally, the practical application of biocomplexity is discussed.

Marine environmental resource managers and consultants require comprehensive, accurate and current data on the status of marine biodiversity in order to fully evaluate resource consent applications that involve development, impact or encroachment within the marine environment, and for identifying areas of coast appropriate for conservation. The role and efficacy of existing global, national and regional marine biodiversity databases in delivering these types of data are evaluated. Consultation with environmental consultants revealed that none regularly, if ever used any existing marine biodiversity database during their routine consulting activities. Moreover, no existing biodiversity database had appropriate data-mining tools, although each was determined to provide information of value to resource managers and environmental consultants operating at national and regional scales; none was deemed to provide the sort of information required to manage marine resources at a local scale. To achieve the objectives of this research programme, resource managers, data users and data compilers were consulted to determine their ideal data and database requirements. Existing biodiversity data sets that included New Zealand marine biodiversity then were searched or procured, and these data and that of a novel data set of species occurring at 296 intertidal and 25 fringe-saline (effectively freshwater) sites within and proximal to the Hauraki Gulf Marine Park (from Mimiwhangata Bay in the north to Tauranga Harbour in the south) were compared with species inventories from environmental consultants operating in this region. Biodiversity data from the 296 saline, comprising presence/absence data for 713 taxa recorded from the survey region were analysed in detail. Significantly different species assemblages were identified amongst these 296 sites, five intertidal habitats being recognised, each with characteristic species assemblages: marine-hard shores, marine-soft shores, brackish-hard shores, brackish-soft shores, and mangrove shores. Species richness and diversity were consistently higher in marine habitats, and greatest on hard substrata. Most sites host unique assemblages of species. A novel index of species richness is proposed, and although the spatial distribution of richness isn’t particularly revealing, as obvious patterns in the distribution of richness are not apparent, this index has value in that the richness of any shore can be compared and contrasted with that of others throughout the region. Augmenting this richness index is a novel index of species rarity. Based on the frequency of occurrence of taxa on shores throughout the survey region, very rare through to ubiquitous taxa are recognised to routinely occur on almost all shores, regardless of the total species richness. Moreover, very rare to uncommon taxa often comprise a disproportionately high percentage of the total species occurring on any given intertidal shore, in any habitat. Accordingly, alarm bells should ring for reviewers of resource consent applications wherein environmental consultants state that an area subject to development ‘hosts no rare, unique or otherwise remarkable species or ecology.’ Two applications of these novel biodiversity data are demonstrated: the relationship between species richness and regional council consented activities is described, with a negative correlation reported for the intensity of disturbance (using the number of consented activities as a proxy for disturbance) and species richness on marine hard shores; and an appraisal of four selection criteria for marine reserves (naturalness, representativeness, uniqueness and complementarities), wherein the intertidal fauna and flora of no existing or proposed marine reserve appears to be natural, unique or representative, and effort seems to have been spent duplicating certain assemblages of species in reserve networks. The former is intuitively obvious, but the latter is alarming, and the ramifications of it far reaching in terms of conservation of the marine environment. Protocols for conducting biodiversity surveys must be established and implemented to elevate the standards of environmental consultants, resulting value judgements on the composition of species, and the likely and actual effects of these developments on the marine environment to ensure that statements made in reports are based on current data rather than perceptions and client expectations. It is possible that resource consents have been issued based on spurious appraisals of the immediate and cumulative effect of discharge on the environment, or of the relative rarity (or appreciation of this) of species that occur within it. Prior to development of the novel Monalisa data set, no existing database or data set existed that provided the information routinely required by managers and consultants to make informed judgements that affect coastal development throughout the survey region. Recommendations for additional research to build on findings detailed herein are made.

In the marine environment, relatively little is known about how the effects of climatic change will manifest into future patterns of biodiversity and community stability, with the exception of recent work on corals in tropical reef ecosystems. In this thesis, I examine quantitatively how patterns of coral reef biodiversity will respond to the impacts of climatic change and provide essential information (i) to address a critical knowledge gap in the understanding of coral reef biodiversity and (ii) predict how a wide range of sessile invertebrates from coral reef ecosystems will respond to a range of potential impacts of climatic change such as increased physical disturbance and rising sea level. An initial descriptive component of my thesis was required to determine the distribution and abundance of a diverse assemblages of sessile non-scleractinian invertebrates, found along gradients of increasing physical disturbance from wave action and increasing intertidal shore height. I also examined the source, intensity and frequency of disturbance along these environmental gradients. This information was used to derive testable hypotheses about the potential impacts of increasing physical disturbance and rising sea level associated with climatic change. I found that physical disturbance had a substantial influence on the types of species that are able to survive in these intertidal rubble habitats, with diversity decreasing at more exposed shores and further down the shore. Physical disturbance was more important for determining the composition of sessile assemblages than other biotic factors such as predation, which only had weak effects on these sessile assemblages. Increased frequency and intensity of waves and storms will increase rates of physical disturbances such as scraping and overturning of rubble plates, which will have a substantial negative impact on biodiversity in these tropical intertidal habitats. These effects may be more complicated that first thought when combined with the effects of rising sea level which will not only alter the extent of inundation, but may also allow wave energy to propagate further up the shore, which has the potential to modify interactions among species through changes to the supply and recruitment of larvae, predator-prey interactions, competition and survival in harsher environments. However, the magnitude of these impacts may depend on how increased physical disturbance and rising sea level affect established species, and whether they will have a substantial effect on larval mortality rates, which currently appears to be limited by physical disturbance. Declines in biodiversity as a result of climatic change over the next 100 years could have important implications for the future health and productivity of coral reef ecosystems, especially given the ecosystem services these organisms provide. A greater understanding of the processes that drive the distribution and abundance of many different types of organisms on coral reefs, and indeed in other ecosystems, will provide essential information that managers can use to better understand and maintain these important ecosystems for future generations.

<p>Human activities have caused acidification of freshwater systems on a large scale resulting in reduced species diversity and ecological functioning in many lakes and streams. However, many naturally acidic freshwater systems have also been found, for instance in northern Sweden. In regions where such naturally acidic aquatic ecosystems have prevailed over evolutionary periods, species diversity and ecological functioning are not automatically impaired due to possible adaptation to the putatively adverse environmental conditions. I studied species diversity patterns and ecological functioning in anthropogenically acidified, naturally acidic, circumneutral, and limed streams to test the adaptation hypothesis and examine the ecological effects of variation in naturally acidic water chemistry. Species diversity was studied using benthic macroinvertebrates, while functioning was modelled using the decomposition rates of leaf litter. In accordance with the evolutionary species pool hypothesis, species richness was reduced more strongly in regions with anthropogenic than natural acidity when compared to circumneutral streams, supporting the adaptation hypothesis. In contrast, the patterns in ecological functioning along the pH-gradients did not differ between regions with anthropogenic and natural acidity, likely resulting from compensation: the biomass of tolerant taxa probably increased which thus rescued the loss in functioning otherwise mediated by the more sensitive taxa. Furthermore, the naturally variable acidic water chemistry clearly supported distinct macroinvertebrate assemblages, as was reflected in differing patterns of species diversity and ecological functioning. Such naturally acidic waters that were rich in dissolved organic carbon supported higher ecosystem process rates and lower species diversity than waters that contained little dissolved organic carbon. Upon liming naturally acidic streams microbial leaf decomposition increased, whereas shredding decreased along with changes in shredder abundances. The abundance of large caddisflies decreased, while the abundance of small stoneflies increased. The results suggest that various types of benthic macroinvertebrates with varying levels of adaptation and tolerance inhabited the hydrochemically variable naturally acidic streams. The distributions of macroinvertebrates in response to different pH levels and differences in acid quality and how these distributions translate into varying patterns of species diversity and ecological functioning are worthy of further investigation. This will likely improve our understanding of how such naturally acidic streams and their biota can be successfully managed.</p>

<p>Biological diversity is one out of four dimensions, characterizing the subject of Biology ac-cording to the school curriculum. As a concept, biological diversity had its break through at the UN environmental conference in Rio de Janeiro in 1992, where the convention about bio-logical diversity, named CBD, was signed. According to the convention, almost all the na-tions of the world have engaged themselves to preserve the national diversity of species, in-cluding the diversity of genetics and ecological systems.</p><p>This thesis focuses the biological diversity from the perspective of school books. The aim is to find out how the biological diversity is presented in biology books for students aged 12-15 years.</p><p>In 1994, the current Swedish secondary and high school curriculum called LPO-94 was pre-sented. The biology books used in this study were published between 1994 and 2007, all of them exist in many editions and are published by three different publishers.</p><p>The conclusion of the study is that all the biology books that were examined have reached different levels of the development in the field of biological diversity.</p>

<p>Global biodiversity is currently being lost at an unprecedented rate, posing a threat to vital ecosystems and hence the generation of ecosystem services that human society is entirely reliant upon. Within the European Community, the EU has set a target of halting biodiversity loss within the territory by 2010. This goal is intended to be operationalized by the implementation of the Habitats Directive and the Birds Directive. These directives constitute the framework for the establishment of a coherent ecological network, referred to as the Natura 2000 network.</p><p>This study examines and analyses the socio-ecological complexities surrounding the designation of Natura 2000 sites in Östhammar municipality, Sweden. The use of a case study-approach to focus on this area is applied in pursuit of identifying and explaining the inherent intricacies in the designation processes and linking them to the broader global context. Throughout Europe, biodiversity exists in a rich variety of grasslands, but only a few studies have been performed to establish appropriate conservation management strategiesrequired for each habitat. This study makes a significant contribution towards shedding light on the Natura 2000 designation process, a phenomenon which has previously been only modestly documented, especially in Sweden. Ecosystem management is discussed and utilized as the theoretical basis for managing ecosystems sustainably, and an important aspect of note is the recognition that the distinction between man and nature needs to be understood as artificial and arbitrary.</p><p>The study explains how social-ecological factors have had a prominent effect on the designation process of Natura 2000 sites. The main determining factor behind the designation process has been the time-constraints, which have affected the designation of SCIs as well as the interaction between the Uppsala CAD and local stakeholders. The lack of adequate participatory approaches used during this process has heightened the risk of compromising the aim of the network: to achieve Favourable Conservation Status (FCS) for natural habitat types as well as species.</p> / <p>Biodiversiteten världen över minskar i en tidigare aldrig skådad hastighet vilket resulterar i ett hot mot fundamentala ekosystem, samt dess produktion av de ekosystemtjänster som det mänskliga samhället är beroende av. På grund av detta har EU satt upp målet att stoppa förlusten av biodiversitet inom unionens gränser tills 2010. Detta mål skall uppnås genom implementeringen av Habitat- och Fågeldirektivet. Dessa direktiv utgör ramen för etableringen av ett sammanhängande ekologiskt nätverk, det så kallade Natura 2000 nätverket.</p><p>Denna studie utreder samt analyserar de socio-ekologiska aspekter som omger utpekandet av Natura 2000 områden i Östhammars kommun, i Uppsala län i Sverige. Genom appliceringen av en fallstudie av området söker denna uppsats att identifiera samt förklara inneboende svårigheter i processen av dessa utpekanden, samt att sätta dem i ett globalt sammanhang. Inom Europa existerar biodiversitet bland annat i olika typer av ängar, dock har endast ett fåtal studier tagit sig an uppgiften att formulera anpassade förvaltningsstrategier för dessa habitat. Denna studie bidrar till att sprida ljus över implementeringen av Natura 2000, ett fenomen som tidigare endast studerats i blygsam utsträckning, speciellt i Sverige. Den teoretiska grunden utgörs ekosystemansatsen, som appliceras för att utvärdera ett uthålligtförvaltande av ekosystem. Vidare understryks vikten av att betrakta ekosystem och mänsklig aktivitet som ett och samma system, och att synen på dem som skilda system bör anses artificiell och motsägelsefull.</p><p>Denna uppsats förklarar hur socio-ekologiska aspekter har påverkat utpekandeprocessen av Natura 2000-områden i Östhammars kommun. De avgörande faktorerna bakom detta är en identifierad tidsbrist, vilket har influerat utpekandet av områden av gemenskapsintresse samt interaktionen mellan Länsstyrelsen i Uppsala och lokala markägare. Bristen på samverkan och information har resulterat i en förhöjd risk av att målet med nätverket inte kommer att nås: att åstadkomma gynnsam bevarandestatus för arter och habitat.</p>

Thesis (doctoral)--Universität Bielefeld, 2003. / Includes bibliographical references (p. 147-152).

Les termites forment un groupe animal important en milieu tropical, où leur richesse spécifique est plus élevée que dans n’importe quel autre écosystème. Ils se nourrissent de matière organique végétale à différent état de décomposition, du bois dur à la matière organique minérale du le sol. Cette diversification du régime alimentaire ne se produit que chez les Termitidae, parfois appelés « termites supérieurs », alors que les autres familles se nourrissent exclusivement de bois ou d’herbe. Les termites humivores sont extrêmement abondants en Amérique du Sud et en Afrique tropicale, mais sont relativement peu étudiés par rapport aux termites xylophages. C’est particulièrement vrai pour le groupe Anoplotermes, qui représente le groupe de termites le moins bien connu. Ce travail vise à faire la lumière sur l’écologie et la diversité de ce groupe strictement humivore, et comprend les sections suivantes : (1) Des échantillonnages standardisés dans sept sites de Guyane Française ont révèle, avec quelques exceptions, que les termites xylophages sont relativement peu spécialisés à un site. Au contraire, les espèces du groupe Anoplotermes, ainsi que les termites humivores en général, sont spécialisés à un type de forêt. Cette spécialisation contribue plus que probablement à la diversification écologique, et donc, à une augmentation de la richesse spécifique des termites humivores. (2) En utilisant les ratios d’isotopiques δ13C et δ15N, nous avons aussi trouvé qu’il existe une spécialisation des espèces le long d’un gradient d’humification chez le groupe Anoplotermes, de l’interface entre le bois pourri et le sol au sol pauvre en matière organique. Donc, au moins deux facteurs favorisent la richesse spécifique du groupe Anoplotermes dans le sol, malgré le manque d’évidence pour une séparation spatiale et temporelle entre les espèces. Cette spécialisation spécifique réduit la compétition interspécifique aux espèces se nourrissant de matière organique au même état de décomposition. (3) Ce mécanisme n’est probablement pas restreint aux espèces du groupe Anoplotermes et le ratio isotopique δ15N varie considérablement entre les termites humivores de manière générale. Les termites humivores comptent des espèces avec des régimes alimentaires différents ne partageant pas toujours les mêmes niches écologiques. Cette diversification du régime alimentaire ne c’est pas produit de manière aléatoire durant l’évolution des termites et les espèces proches tendent à se nourrir du même substrat. (4) Au niveau intraspécifique, il semble que la compétition contraigne la dynamique des colonies. En effet, chez A. banksi, nous avons trouvé que les nids matures sont surdispersés. Les nouveaux nids se trouvent principalement à une certaine distance des nids établis, plus particulièrement dans les trous laissés par les nids morts. Si ce patron est le résultat d’une sélection des sites de nidification, ou plutôt d’une exclusion compétitive reste sujet à discussion, mais met néanmoins en évidence la présence de compétition chez les termites humivores du groupe Anoplotermes. (5) Au vu de la richesse spécifique locale du groupe Anoplotermes, le nombre d’espèces décrites reste remarquablement bas. Après inspection du matériel type, seuls 30 espèces du groupe se sont avérés valides en Amérique du Sud, alors que 80% des espèces que nous avons collectées sont nouvelles pour la science. Cette disproportion entre ce qui est connu et la diversité réelle du groupe, met en évidence le besoin de réaliser des études supplémentaires pour améliorer la connaissance de ce groupe peu connu, le groupe Anoplotermes.

Die Vegetationskomposition und –struktur, beispielsweise die unterschiedliche Architektur von Bäumen, Sträuchern, Gräsern und Kräutern, bietet ein großes Spektrum an Habitaten und Nischen, die wiederum eine hohe Tierdiversität in den Savannensystemen des südlichen Afrikas ermöglichen. Dieses Ökosystem wurde jedoch über Jahrzehnte weltweit durch intensive anthropogene Landnutzung (z.B. Viehwirtschaft) nachhaltig verändert. Dabei wurden die Zusammensetzung, Diversität und Struktur der Vegetation stark verändert. Überweidung in Savannensystemen führt zu einer Degradation des Habitates einhergehend mit dem Verlust von perennierenden Gräsern und krautiger Vegetation. Dies führt zu einem Anstieg an vegetationsfreien Bodenflächen. Beides, sowohl der Verlust an perennierenden Gräsern und krautiger Vegetation sowie der Anstieg an vegetationsfreien Flächen führt zu verbesserten Etablierungsbedingungen für Sträucher (z.B. Rhigozum trichotomum, Acacia mellifera) und auf lange Sicht zu stark verbuschten Flächen. Die Tierdiversität in Savannen ist hiervon entscheidend beeinflusst. Mit sinkender struktureller Diversität verringert sich auch die Tierdiversität. Während der Einfluss von Überweidung auf die Vegetation relativ gut untersucht ist sind Informationen über den Einfluss von Überweidung auf die Tierdiversität, speziell für Reptilien, eher spärlich vorhanden. Zusätzlich ist sehr wenig bekannt zum Einfluss auf die Populationsdynamik (z.B. Verhaltensanpassungen, Raumnutzung, Überlebensrate, Sterberate) einzelner Reptilienarten. Ziel meiner Doktorarbeit ist es den Einfluss von Überweidung durch kommerzielle Farmnutzung auf die Reptiliengemeinschaft und auf verschiedene Aspekte der Populationsdynamik der Echse Pedioplanis lineoocellata lineoocellata zu untersuchen. Hinsichtlich bestimmter Naturschutzmaßnahmen ist es einerseits wichtig zu verstehen welchen Auswirkungen Überweidung auf die gesamte Reptiliengemeinschaft hat. Und zum anderen wie entscheidende Faktoren der Populationsdynamik beeinflusst werden. Beides führt zu einem besseren Verständnis der Reaktion von Reptilien auf Habitatdegradation zu erlangen. Die Ergebnisse meiner Doktorarbeit zeigen eindeutig einen negativen Einfluss der Überweidung und der daraus resultierende Habitatdegradation auf (1) die gesamte Reptiliengemeinschaft und (2) auf einzelne Aspekte der Populationsdynamik von P. lineoocellata. Im Teil 1 wird die signifikante Reduzierung der Reptiliendiversität und Abundanz in degradierten Habitaten beschrieben. Im zweiten Teil wird gezeigt, dass P. lineoocellata das Verhalten an die verschlechterten Lebensbedingungen anpassen kann. Die Art bewegt sich sowohl häufiger als auch über einen längeren Zeitraum und legt dabei größere Distanzen zurück. Zusätzlich vergrößerte die Art ihr Revier (home range) (Teil 3). Im abschließenden Teil wird der negative Einfluss von Überweidung auf die Populationsdynamik von P. lineoocellata beschrieben: In degradierten Habitaten nimmt die Populationsgröße von adulten und juvenilen Echsen ab, die Überlebens- und Geburtenrate sinken, währen zusätzlich das Prädationsrisiko ansteigt. Verantwortlich hierfür ist zum einen die ebenfalls reduzierte Nahrungsverfügbarkeit (Arthropoden) auf degradierten Flächen. Dies hat zur Folge, dass die Populationsgröße abnimmt und die Fitness der Individuen verringert wird, welches sich durch eine Reduzierung der Überlebens- und Geburtenrate bemerkbar macht. Und zum anderen ist es die Reduzierung der Vegetationsbedeckung und der Rückgang an perennierenden Gräsern welche sich negativ auswirken. Als Konsequenz hiervon gehen Nischen und Mikrohabitate verloren und die Möglichkeiten der Reptilien zur Thermoregulation sind verringert. Des Weiteren hat dieser Verlust an perennierender Grasbedeckung auch ein erhöhtes Prädationsrisikos zur Folge. Zusammenfassend lässt sich sagen, dass nicht nur Bäume und Sträucher, wie in anderen Studien gezeigt, eine bedeutende Rolle für die Diversität spielen, sondern auch das perennierende Gras eine wichtige Rolle für die Faunendiversität spielt. Weiterhin zeigte sich, dass Habitatdegradation nicht nur die Population als gesamtes beeinflusst, sondern auch das Verhalten und Populationsparameter einzelner Arten. Des Weiteren ist es Reptilien möglich durch Verhaltensflexibilität auf verschlechterte Umweltbedingen zu reagieren. / In semi-arid savannah ecosystems, the vegetation structure and composition, i.e. the architecture of trees, shrubs, grass tussocks and herbaceous plants, offer a great variety of habitats and niches to sustain animal diversity. In the last decades intensive human land use practises like livestock farming have altered the vegetation in savannah ecosystems worldwide. Extensive grazing leads to a reduction of the perennial and herbaceous vegetation cover, which results in an increased availability of bare soil. Both, the missing competition with perennial grasses and the increase of bare soils favour shrub on open ground and lead to area-wide shrub encroachment. As a consequence of the altered vegetation structure and composition, the structural diversity declines. It has been shown that with decreasing structural diversity animal diversity decline across a variety of taxa. Knowledge on the effects of overgrazing on reptiles, which are an important part of the ecosystem, are missing. Furthermore, the impact of habitat degradation on factors of a species population dynamic and life history, e.g., birth rate, survival rate, predation risk, space requirements or behavioural adaptations are poorly known. Therefore, I investigated the impact of overgrazing on the reptile community in the southern Kalahari. Secondly I analysed population dynamics and the behaviour of the Spotted Sand Lizard, Pedioplanis l. lineoocellata. All four chapters clearly demonstrate that habitat degradation caused by overgrazing had a severe negative impact upon (i) the reptile community as a whole and (ii) on population parameters of Pedioplanis l. lineoocellata. Chapter one showed a significant decline of regional reptile diversity and abundance in degraded habitats. In chapter two I demonstrated that P. lineoocellata moves more frequently, spends more time moving and covers larger distances in degraded than in non-degraded habitats. In addition, home range size of the lizard species increases in degraded habitats as shown by chapter three. Finally, chapter four showed the negative impacts of overgrazing on several population parameters of P. lineoocellata. Absolute population size of adult and juvenile lizards, survival rate and birth rate are significantly lower in degraded habitats. Furthermore, the predation risk was greatly increased in degraded habitats. A combination of a variety of aspects can explain the negative impact of habitat degradation on reptiles. First, reduced prey availability negatively affects survival rate, the birth rate and overall abundance. Second, the loss of perennial plant cover leads to a loss of niches and to a reduction of opportunities to thermoregulate. Furthermore, a loss of cover and is associated with increased predation risk. A major finding of my thesis is that the lizard P. lineoocellata can alter its foraging strategy. Species that are able to adapt and change behaviour, such as P. lineoocellata can effectively buffer against changes in their environment. Furthermore, perennial grass cover can be seen as a crucial ecological component of the vegetation in the semi-arid savannah system of the southern Kalahari. If perennial grass cover is reduced to a certain degree reptile diversity will decline and most other aspects of reptile life history will be negatively influenced. Savannah systems are characterised by a mixture of trees, shrubs and perennial grasses. These three vegetation components determine the composition and structure of the vegetation and accordingly influence the faunal diversity. Trees are viewed as keystone structures and focal points of animal activity for a variety of species. Trees supply animals with shelter, shade and food and act as safe sites, nesting sites, observation posts and foraging sites. Recent research demonstrates a positive influence of shrub patches on animal diversity. Moreover, it would seem that intermediate shrub cover can also sustain viable populations in savannah landscapes as has been demonstrated for small carnivores and rodent species. The influence of perennial grasses on faunal diversity did not receive the same attention as the influence of trees and shrubs. In my thesis I didn’t explicitly measure the direct effects of perennial grasses but my results strongly imply that it has an important role. If the perennial grass cover is significantly depleted my results suggest it will negatively influence reptile diversity and abundance and on several populations parameters of P. lineoocellata. Perennial grass cover is associated with the highest prey abundance, reptile diversity and reptile abundance. It provides reptiles both a refuge from predators and opportunities to optimise thermoregulation. The relevance of each of the three vegetation structural elements is different for each taxa and species. In conclusion, I can all three major vegetation structures in the savannah system are important for faunal diversity.