Rozprawy doktorskie na temat „Rangeland conservation”

The Upper Salinas Headwaters Conservation Plan is an effort to understand the cultural and ecosystem resources in the region, develop tools for conservation planning, and suggest a strategy and plan of action for implementation of those strategies. The plan covers a 218 square mile area between the Santa Lucia and the La Panza mountain ranges, south of Atascadero and east of the City of San Luis Obispo. The Conservation Area consists of rugged terrain made up of vast-relatively untouched open space. The area consists of several different vegetative communities including oak savannah grasslands, mixed hardwood and oak stands, shrubland, wetland and riparian corridors. The region is host to a number of land uses predominantly agriculture (mainly cattle ranching), some urban development, outdoor recreation, and a few mining operations. Approximately fifty-five percent of the acreage within the Conservation Area is designated public land (federal, state, and county), while the remaining acreages are dominantly private lands with Rural or Agriculture designations. Places of interest within the Conservation Area include the Upper Salinas River, Santa Margarita Reservoir, the historic Santa Margarita Ranch, and the town of Pozo. The region that contains the Conservation Area has been identified as having significant ecological resources (migratory corridors, important/rare vegetation communities, and a system of tributaries critical to Salinas River water quality and supply downstream.) The recognition of this important area has come from the California Rangeland Conservation Coalition statewide landscape priorities, The Nature Conservancy, the South Coast Wildlands Program, and a countywide report completed for The Conservancy by Catherine Lambert in 2007, which utilized Geographic information Systems (GIS) to assess ecosystem attributes and growth pressure parameters. The region containing the Conservation Area received a moderate to high combined score as a result of the assessment, suggesting a need for conservation efforts and resources from the Conservancy. The Conservation Area is based roughly on the shape of the subwatersheds that make up part of the larger Upper Salinas watershed. Several headwater tributaries flow into the Salinas River; a river utilized by several municipalities and agricultural operations as it flows north to Monterey Bay. Land use changes in the region can negatively affect water quality and supply downstream as well as degrade important habitat for fish and wildlife. Projected urban develop pressures from the City of Atascadero and an increase in more intensive agricultural production places increasing pressure on both local ranching operations and the regional ecosystem. The large amount of contiguous public land presents an opportunity for a conservation strategy aimed at creating expansive public-private protected lands that will ensure long-term protection of agricultural, hydrological, and wildlife resources. This conservation plan was developed primarily using GIS information from The Conservancy and data used with permission from the County of San Luis Obispo. GIS maps were created and utilized along with aerial photos from Google Earth to analyze the landscape for the following: vegetation communities stream flow direction and order types of development land ownership/parcel data agricultural soils geology existing protected areas conservation potential potential project sites for restoration/enhancement The GIS maps, aerial photo analysis, and information collected from interviews with several family ranchers are intended to be used as decision-support tools for future conservation projects in the region. However, for this plan, strategic and implementation recommendations are suggested in the form of long-term conservation agreements, land use management and restoration/enhancement techniques based on analysis of the information that was collected. The conservation strategy of this plan emphasizes the utilization of existing protected landscapes, primarily public land, along with the establishment of partnerships with private landowners within the Conservation Area to develop large contiguous tracts of protected land in the headwaters region of the Salinas River. The ranching heritage in the region, diversity of habitat and wildlife, sensitivity of hydrological resources, moderate to high levels of development potential from urban development, and more intensive agricultural production makes the Conservation Area in the Upper Salinas Watershed an essential target for conservation efforts.

Since pastoralism began in Australia???s rangelands, the number of artificial watering points (AWPs) has increased dramatically, such that today, few areas of rangeland are further than 10 km from water. This increased availability of water has caused many ecological impacts. Unfortunately, such impacts are poorly understood in the context of an Australian conservation reserve, thus hindering strategic management. This study examined the spatial distribution of vertebrate (kangaroos, small mammals, lizards and avifauna) and vegetative variables around open AWPs as well as AWPs that have been closed since pastoralism (sheep-grazing) ceased nearly thirty years ago in Sturt National Park, arid New South Wales. The study also examined vertebrate use of AWPs, with a particular emphasis on kangaroos and avifauna. The study revealed that most variables showed few differences in spatial distribution with distance from open and closed AWPs, thus suggesting that the observed piospheric impacts were primarily attributable to historical sheep-grazing. Indeed, piospheric patterns were weak suggesting some recovery over the last thirty years. That kangaroos did not exhibit water-focused grazing is no surprise, since despite their regular use of AWPs, particularly during hot, dry times, the current spatial arrangement of AWPs facilitates regular travel to, and from, such resources allowing kangaroos, like much other fauna, to distribute themselves in relation to food and shelter preferences rather than in relation to water supply. In contrast, the majority of avifaunal groups (excluding ground-dwelling species) were clustered around open AWPs, often irrespective of season, because of food and water requirements. Such spatial concentrations of avifauna are thought to cause a range of interspecific effects. Experimental AWP closure and GIS modelling showed that whilst closure of AWPs will increase the average distance to water, which will have key benefits, the majority of areas in Sturt National Park would still be accessible to most water-dependent species even if all unused AWPs were closed. Strategic retention of AWPs to replace water sources lost since European settlement, aid threatened and migratory species??? conservation and enhance nature-based tourism opportunities is thus recommended and an example of a strategic management and monitoring plan outlined.

Thesis (MScConEcol)--Stellenbosch University, 2013.
ENGLISH ABSTRACT: Reductionism, an approach to understanding complex systems based on reducing the system to its individual components and the interactions between these components, is the linear and rigid approach to traditional management and research that allows us to understand complicated systems. Yet its application to complex systems has likely added to the degradation of social-ecological systems. In recognition of this, there is currently a shift to holism: the concept that a system is greater than the sum of its components and that the system has emergent properties that are only present through the complex interactions of the whole system. The inclusion of this natural complexity within social-ecological systems is thought to promote resilience – the ability of a system to absorb shock and thus promote sustainability. However, these concepts are largely theoretical and few examples exist that demonstrate ways of transferring them to pragmatic land management. Holistic ManagementTM (HM) could potentially be such a working example. It is a decision-making framework that provides a holistic context for the adaptive management of natural resources. However, limited peer-reviewed research has been applied to this potential to promote sustainability. Thus the current study aimed to address this apparent gap by determining if HM land managers were a distinct group from non-HM (NHM) land managers in regards to their management practices and if HM land managers had a greater adaptive capacity (the management of resilience) than non-HM land managers. The study was conducted in a community of livestock farmers in the arid rangelands of the Karoo, South Africa. Data were mainly gathered through face-to-face interviews with land managers – including 20 self-defined HM land managers and 20 self-defined NHM land managers. To compare the reported management approaches of land managers, two scoring systems were developed. The HM Adoption Index measured the extent to which participants were aligned with key principles and practices of HM (including having a holistic goal, testing decisions, applying the Holistic Planned Grazing, demonstrating continuous learning and innovation). The Adaptive Capacity Index measured the extent to which participants demonstrated key traits of adaptive capacity as identified from the literature. In addition, participants were also asked to describe the strategies they apply to deal with local livestock farming challenges including parasite control, predation management and drought management. A significant difference was found between HM and NHM land managers for both the HM Adoption Index and Adaptive Capacity Index (p<0.01). The majority of HM land managers adopted ―true holistic and ―adaptive management practices (80%) while NHM land managers were mostly ―semi holistic and ―coping (65%). HM land managers also notably tended to report more innovative and environmentally aware methods in dealing with farming challenges and were more likely to be part of study groups which build social capital and promote social learning. Results imply that HM provides a framework that introduces holistic principles to land management, making the holistic context and resilience accessible to individual managers for practical day-to-day decision-making.
AFRIKAANSE OPSOMMING: Reduksie, 'n benadering om komplekse sisteme te verstaan deur om die sisteme te besnoei tot sy individuele komponente en interaksies tussen die komponente, is die liniêre en rigiede benadering tot tradisionele bestuur en navorsing. Dit laat ons toe om komplekse sisteme te verstaan. Tog het die toepassing van reduksie op komplekse sisteme waarskynlik bygedra tot die degradasie van sosiaal-ekologiese sisteme. In herkenning van laasgenoemde is daar tans 'n skuif na holisme: die konsep dat 'n sisteem groter is as die somtotaal van al sy komponente en dat die sisteem voortkomende eienskappe het wat net navorekom deur die komplekse interaksies van die sisteem. Die insluiting van die natuurlike kompleksiteit binne sosiaal-ekologiese sisteme bevorder moontlik weerstandigheid; die vermoë van 'n sisteem om 'n skok te absorbeer en so volhoubaarheid te bevorder. Hierdie konsepte is egter meestal teoreties en min voorbeelde bestaan wat metodes demonstreer om die konsepte oor te dra na pragmatiese grondbestuur. Holistiese BestuurTM (HB) kan moontlik so 'n werkende voorbeeld wees. Dit is 'n raamwerk vir besluitvorming wat 'n holistiese konteks verskaf vir die aanpasbare bestuur van natuurlike hulpbronne. Daar is min eweknie-hersiende navorsing wat HB se potensiaal om volhoubaarheid te bevorder ondersoek. Dus het die huidige studie beoog om die gaping aan te spreek deur te bepaal of HB praktiseerders onderskei kan word van 'n groep van nie-HB (NHB) praktiseerders in terme van bestuurspraktyke en of HB praktiseerders 'n groter aanpasbaarheid (die bestuur van weerstandigheid) toon as NHB praktiseerders. Die studie het plaasgevind in 'n gemeenskap van veeboere in die dorre veld van die Karoo, Suid Afrika. Data was versamel deur aangesig tot aangesig onderhoude met grondbestuurders; 20 self-geïdentifiseerde HB praktiseerders en 20 self-geïdentifiseerde NHB praktiseerders. Twee puntestelsels is ontwikkel om die gerapporteerde benaderings van grondbestuurders te vergelyk. Die HB Toepassing Puntelys het gemeet tot watter mate 'n deelnemer inskakel met die kern beginsels van HB (insluitend om 'n holistiese doelwit te hê, om besluite te toets, om Holistiese Beplande BewydingTM toe te pas en om 'n voortsetting van leer en innovasie te demonstreer). Die Aanpasbaarheid Puntelys het gemeet tot watter mate 'n deelnemer die kern kenmerke van aanpasbaarheid, soos geïdentifiseer in literatuur, demonstreer. Bykomend was deelnemers ook gevra om die strategieë te beskryf wat hulle toepas om die uitdagings van plaaslike veeboerdery tegemoed te kom insluitend die beheer van parasiete, die bestuur van roofdiere en die bestuur tydens droogtes. 'n Betekenisvolle verskil was gevind tussen HB en NHB praktiseerders vir die HB Toepassing Puntelys en die Aanpasbaarheid Puntelys (p<0.01). Die meederheid van HB praktiseerders het ―ware holistiese en ―aanpasbare praktyke toegepas (80%) terwyl NHB praktiseerders se metodes meestal ―semi-holisties en ―korttermyn probleem hantering was (65%). HB praktiseerders het ook 'n waarneembare neiging gehad om innoverende en omgewingsbewuste metodes te rapporteer in verband met veeboerdery uitdagings en was meer waarskynlik deel van 'n studie groep wat sosiale kapitaal gebou en sosiale leer bevorder het. Die resultate het aangedui dat HB 'n raamwerk voorsien wat holistiese beginsels oordra na grondbestuur en so die holistiese konteks en weerstandigheid toeganklik maak vir die individuele bestuurder vir daaglikse praktiese besluitneming en toepassing.

Environmental issues are often complex with many different constituents operating according to a broad range of communication techniques. In order to foster negotiations, different perspectives need to be articulated in lucid ways sensitive to various viewpoints and circumstances. In my thesis I investigate how certain approaches to environmental discourse effect dialogue and negotiation. My first two chapters focus on environmental problems surrounding rangeland ecology along the U.S./Mexico border; whereas the last two chapters explore more theoretical conflicts concerning the philosophy of nature. Throughout the thesis I show the significance of nonhumans (prairie dogs, cattle, biological assessment sheets, environmental laws, etc.) in the human community. Only by considering the roles of nonhumans do we broaden and enrich the conversation between ourselves concerning environmental issues.

Thesis (MSc (Conservation Ecology and Entomology))--University of Stellenbosch, 2010.
ENGLISH SUMMARY: Protected areas do not always achieve the desired level of biodiversity conservation, while often reducing the welfare of indigenous communities by reducing availability of land for subsistence. Traditional agricultural landscapes are significant biodiversity refugia and can contribute meaningfully to conservation. Rangelands comprise one-third to one-half of the world’s terrestrial surface, providing livelihoods for around 220 million people, usually in a communal subsistence system. Colonial practices impinged on traditional land-use practices with far-reaching social and environmental impacts. This has resulted in management based on assumptions regarding vegetation dynamics and traditional lifestyles that are increasingly shown to be inaccurate. A comparison of a vegetation survey based on conventional scientific methods and a survey of the perceptions of pastoralists was undertaken to highlight differences and similarities between the two knowledge systems with the hope of providing guidelines for more sustainable land-use practices in the communal rangelands of Namaqualand, South Africa. Vegetation responses to removal of grazing pressure revealed complex interactions that do not correspond with the prevailing management paradigm. Rather than a predictive relationship between livestock and vegetation, environmental factors play a large role in determining plant composition, abundance and cover. Pastoralists’ perceptions reflected this complexity in rangeland resource dynamics. The impact of livestock on rangeland resource dynamics was perceived by herders to be secondary to a range of environmental and climatic factors. Both sets of results were at odds with the theories that currently govern management in this system. Studies in rangeland systems must take the complexity of the subject into account. Research into such socio-ecological systems must take a multiplicity of factors – social, environmental, economic, political and other – into account. Implications for management are that it is inappropriate to adhere strictly to the conventional, conservative strategies that are prescribed by conservation and agricultural authorities. Rather, a more flexible, opportunistic grazing strategy would allow the persistence of traditional subsistence livelihoods without serious negative consequences for biodiversity conservation.
AFRIKAANSR OPSOMMING: Die instelling van beskermde gebiede lewer nie altyd die gewenste vlak van biodiversiteitsbewaring, terwyl die welvaart van plaaslike gemeenskappe dikwels daaronder ly deur die afname in grond beskikbaar vir bestaanspraktyke. Tradisionele landboulandskappe is beduidende biodiversiteitshawens wat ‘n belangrike bydrae tot bewaring kan maak. Weivelde bevat ‘n derde tot ‘n helfte van die wêreld se landsoppervlakte en ondersteun rondom 220 miljoen mense, gewoonlik binne ‘n gemeenskaplike bestaansstelsel. Kolonialisasie het inbraak gemaak op tradisionele bestuurspraktyke, met verrykende sosialeen omgewingsimpakte. Dit het gelei tot bestuurspraktyke gebaseer op standpunte oor plantegroeidinamika en traditionele lewenswyses wat toenemend verkeerd bywys word. ‘n Vergelyking van ‘n plantegroei opname gebaseer op konvensionele wetenskaplike metodes en ‘n opname van die standpunte van veewagters is onderneem om die verskille en ooreenkomstes tussen die twee kennisstelsels uiteen te lê met die hoop om riglyne vir meer volhoubare bestuurspraktyke in die meentgronde van Namakwaland, Suid-Afrika te verskaf. Plantegroei reaksies tot die verwydering van weidingsdruk wys op komplekse interaksies wat nie ooreenstem met die heersende bestuursparadigma. Eerder as ‘n voorspelbare verwantskap tussen vee en plantegroei, omgewingsfaktore speel ‘n groot rol in die bepaling van plantgemeenskapsamestelling, -getalle en grondbedekking. Die veewagters se standpunte het hierdie kompleksiteit in plantegroeidinamika weerspiëel. Die impak van vee op die weiveldhulpbron is deur veewagters as sekondêr beskou teenoor ‘n reeks omgewings- en klimaatsfaktore. Beide stel resultate is in teenstelling met die teoriëe wat tans bestuur in hierdie stelsel bepaal. Studies in weiveldstelsels moet die kompleksiteit daarvan in ag neem. Navorsing oor hierdie sosio-ekologiese stelsels moet ‘n verskeidenheid faktore – sosiale-, omgewings-, ekonomiese-, politiese- en ander – in ag neem. Implikasies vir bestuur is dat dit onvanpas is om te volhard met konvensionele, konservatiewe strategiëe voorgeskryf deur bewarings- en landboukundige gesagte. ‘n Meer aanpasbare, voordeelnemende weidingsstrategie sal die voortbestaan van traditionele bestaanslewenspraktyke toelaat sonder ernstige negatiewe nagevolge vir biodiversiteitsbewaring.

Thesis (MScConEcol (Conservation Ecology and Entomology))--University of Stellenbosch, 2011.
ENGLISH ABSTRACT: I evaluated the impact of Prosopis invasion and clearing on ecological structure, function and agricultural productivity in heavily grazed Nama Karoo rangeland on two sheep farms near the town of Beaufort West in the Western Cape Province of South Africa. My aims were to (1) determine the effects of invasion and clearing on rangeland vegetation composition, diversity (alien and indigenous species richness) and structure (alien and indigenous species cover), soil vegetation cover (plant canopy and basal cover) and agricultural productivity (grazing capacity), (2) describe the vegetation processes that underlay the invasion and clearing impacts and (3) evaluate the success of clearing in facilitating unaided restoration of ecological structure, function and agricultural productivity in formerly invaded rangeland. I hypothesised that invasion would significantly change rangeland vegetation composition and structure, leading to greater alien species richness and cover and lower indigenous species richness and cover while clearing would lead to lower alien species diversity and cover and greater indigenous species richness and cover. In addition I hypothesized that invasion would reduce rangeland plant canopy and basal cover and grazing capacity while clearing would substantially increase them. Finally I predicted that vegetation composition, alien and indigenous species cover and richness, plant canopy and basal cover and grazing capacity would revert to pre-invasion status and levels within four to six years of clearing. My results suggest that in heavily grazed Nama Karoo rangeland Prosopis invasion (~15 percent canopy cover) and clearing can significantly change rangeland vegetation composition, with invasion leading to greater alien species cover and lower indigenous species richness, while clearing leads to lower alien species richness and cover and greater indigenous species richness and cover. However invasion seems to have no effect on alien species richness and overall indigenous species cover. Clearing appears to facilitate the spontaneous restoration of alien species cover and indigenous species richness within four to six years but not species composition, alien species richness and indigenous species cover. In addition my results also indicate that Prosopis invasion can lower rangeland plant canopy and basal cover and grazing capacity while clearing, even under heavy grazing, can substantially raise them. Clearing however does not seem to facilitate the restoration of rangeland plant canopy and basal cover and grazing capacity to pre-invasion levels within four to six years after clearing.
AFRIKAANSE OPSOMMING: Ek het die impak van Prosopis indringing en verwydering van indringers op ekologiese struktuur, funksie en landbou produktiwiteit in ‘n swaar beweide Nama Karoo gebied op twee skaapplase naby Beaufort-Wes in die Wes-Kaap provinsie van Suid-Afrika geëvalueer. My doelwitte was om (1) te bepaal wat die gevolge van die indringing en verwydering van indringers op die natuurlike plantegroei samestelling, diversiteit (uitheemse en inheemse spesiesrykheid) en struktuur (uitheemse en inheemse spesies bedekking) sal wees, sowel as die effek op plantegroei bedekking (kroon en basalebedekking) en landbou produktiwiteit (weidingkapasiteit), (2) die plantegroei prosesse te beskryf wat onderliggend deur die impakte van indringing en verwydering van indringers veroorsaak word, en (3) die sukses van die verwydering van indringers te evalueer deur die fasilitering van blote restorasie van ekologiese struktuur en funksie en landbou produktiwiteit in voorheen ingedringde gebiede. My hipotese is dat indringing ‘n aansienlike verandering in natuurlike plantegroeisamestelling en struktuur sal veroorsaak, wat sal lei tot groter uitheemse spesiesrykheid en bedekking met minder inheemse spesiesrykheid en bedekking, terwyl die verwydering van indringers sou lei tot minder uitheemse spesie diversiteit en bedekking met 'n groter inheemse spesiesrykheid en bedekking. Verder vermoed ek dat indringing die natuurlike kroon- en basalebedekking en weidingkapasiteit sal verminder, terwyl die verwydering van indringers dit aansienlik sal verhoog. Ten slotte voorspel ek dat plantegroei samestelling, uitheemse en inheemse spesiesbedekking en -rykheid, kroon- en basalebedekking en weidingkapasiteit sou terugkeer na voor-indringing status en vlakke binne vier tot ses jaar na die verwydering van indringers. My resultate daarop dat die indringing van Prosopis (~ 15 persent kroonbedekking) en die verwydering van indringers in swaar beweide Nama Karoo gebiede ‘n aansienlike verandering in die gebied se natuurlike plantegroei samestelling toon, waar indringing gelei het tot groter uitheemse spesiesbedekking en minder inheemse spesiesrykheid, terwyl die verwydering van indringers lei tot minder uitheemse spesiesrykheid en groter inheemse spesiesrykheid en - bedekking. Dit lyk egter of indringing geen effek op uitheemse spesiesrykheid en algehele inheemse spesiesbedekking het nie. Die verwydering van indringers blyk om die spontane herstel van indringerbedekking en inheemse spesiesrykheid binne vier tot ses jaar te fasiliteer, maar nie spesiesamestelling, uitheemse spesiesrykheid of inheemse spesiesbedekking nie. Benewens dui my resultate ook aan dat Prosopis indringing die natuurlike kroon- en basalebedekking sowel as weidingskapasiteit verlaag, terwyl die verwydering van indringers, selfs onder swaar beweiding, die bedekking aansienlik kan verhoog. Verwydering van indringers lyk egter nie asof dit die herstel van die gebied se natuurlike kroon- en basalebedekking en weidingkapasiteit na voor-indringing vlakke toe kan fasiliteer binne vier tot ses jaar na die verwydering van indringers nie.

Thesis (MScConsEcol (Conservation Ecology and Entomology))--Stellenbosch University, 2008.
The widespread ecological impacts of overgrazing by livestock within the Succulent Karoo have received considerable attention. Literature shows communal and commercial rangelands have been thoroughly studied, and vegetation responses have been investigated in an attempt to understand the effects of overgrazing. Regarding animal species, literature is in short supply. In a one-year study of small mammal assemblages, the effect of the rangelands, and subsequently vegetation, on small mammal assemblages was examined, as well as the effects on number of occupied, unoccupied and collapsed burrows. This study shows that vegetation composition differs between rangelands, with a greater perennial shrub cover on the communal rangelands and a greater perennial succulent cover on commercial rangelands, consequently creating different habitats for animal assemblages. This study supports the notion of small mammal composition relating to vegetation structure, with certain species being impacted by heavy grazing. Four small mammal species were found in greater abundances on commercial rangelands, with one being exclusive, while communal rangelands were exclusively occupied by three nocturnal species. Diet and habitat requirements are the most important factors regarding species occurrence. With small mammal species composition differing between rangelands, and species richness not being affected by rangeland type, this study illustrates that the disappearance of certain species may arise without these different rangelands. This could result in reduced species richness, and thus diversity being lost. Regarding species present on both rangelands, no differences were observed in body mass, body size or body condition. Despite no differences found in body condition, calculating a body condition index is a good method for investigating how a species is coping within an environment. The proportion and number of occupied and collapsed burrows can be seen as a measure of trampling effect. It was expected for grazing intensity, as well as vegetation changes, to affect the occurrence of such burrows. This study showed differences between the communal and commercial rangelands as negligible. As expected, numbers of burrowing small mammal species were negatively correlated with numbers of collapsed burrows. However, a lack of consistency deemed this result unimportant. Results show that the effects of overgrazing on small mammal populations are complex and require more attention if to be fully explained. This study provides insights into the effects of land use on small mammals and burrow numbers, which have implications for the conservation of these species within arid regions.

The persistence of many species of carnivore may depend on their survival outside protected areas where they come into conflict with humans and their livestock. Knowledge of these wildlife populations and of the perceptions and attitudes of the stakeholders in the areas in which they live is of critical importance in the quest for coexistence. The Ghanzi farmlands in western Botswana are a prime example of semi-arid rangeland where humans, domestic livestock and wildlife live side by side with varying degrees of success. But little research has been conducted in the area into either the wildlife or the white Afrikaner minority who own the majority of the land. This study aimed to fill some of these gaps in knowledge by adopting an interdisciplinary approach, and employing methodologies from both the biological and social sciences, to determine the potential for conservation of carnivores in the area. The farm block was found to contain good carnivore species diversity and a reduced, but healthy, naturally occurring prey base. Densities of cheetah and leopard were low, but comparable to, or better than, those reported for other similar environments. A good population of brown hyaena was found to exist in the area which could be of importance to the conservation of the species as a whole. The farming community were supportive of conservation in principle, but generally intolerant of predators that killed their livestock. A wide variety of land management and livestock husbandry practices were apparent, with some farmers prepared to do more than others to actively protect their livestock. Farmers with small stock suffered from greater levels of depredation than those who farmed only cattle, while some species of predator elicited greater feelings of antipathy than others. Some farmers professed a distrust of government interference in their affairs which served to hamper efforts to obtain reliable data on livestock depredation and monitor the lethal control of predators.

There is concern that the communal rangelands of Botswana are overstocked with cattle, and that this has led to unwanted ecological changes. These changes are assumed to be most prominent around boreholes. This study describes vegetation and soil piospheres around boreholes in Eastern Botswana and investigates factors associated with their development. The classical range succession model and its modifications, the bush encroachment theories and the soil-nutrient transfer model, have been applied here to explain changes in vegetation and soil variables with distance from artificial water points. Data on soil texture, soil nutrients, vegetation species composition and cover, dung weight and bare ground were collected from boreholes of different ages, with different numbers of cattle using them. Piosphere patterns were observed. However, some of the patterns were not in accordance with the classical range succession model and the bush encroachment theories. The frequent occurrence of palatable grasses (Panicum maximum, Setaria verticiliata and Digitaria milanjiand) nearer to water points where the grazing pressure is highest, and of unpalatable ones (Aristida congesta and Eragrostis rigidior) further away, where the grazing pressure is minimal, contradicts the classical range succession model. Total tree cover along the gradient did not show any changes, which contradicts bush encroachment theory (two-layer soil moisture model). The concentration of soil nutrients and dung weight close to boreholes was well predicted by the soil-nutrient transfer model. The frequency of Acacia tortilis and Dicrostachys cinerea and bare patches, increased towards boreholes. Grass cover, occurrence of Terminalia sericea, Boscia albitrunca and Combretum apiculatum increased with distance from water points. The results suggest that the range succession model and its modification, the twolayer soil moisture model, cannot satisfactorily explain vegetation changes with distance from water points. Species composition at a point may be affected by the growth, survival, recovery and reproductive strategies of different species, fire, selectivity of browsers and nutrients status, as well as grazing disturbance. Therefore, the 'state and transition' model is recommended, as it considers factors that are ignored by the classical range succession model, and is appropriate for analysing vegetation change under highly variable rainfall. The adverse impacts of grazing around boreholes could be reduced by controlling cattle distribution on the range as a whole.

This study investigated the vegetation and soil characteristics in relation to distance from water points under different land management systems in semi-arid rangelands of South Africa. Six study sites, two each from communal grazing, commercial farming and game reserves were selected. Two watering points were selected in each study site. Two 500 m transects were laid from the selected watering points. Each transect was divided into sub-transects at 25 m, 50m, 100m, 200m, 300m and 500m from water points. A 100 m2 plot was marked in each sub-transect to record grass biomas, species composition, structure and distribution of woody vegetation and physical and chemical soil properties. Data were collected for two seasons 2012/13 (winter and summer). Thirty and 41 grass and woody species respectively were identified in all study areas. The most common and dominating grass species include Cynodon dactylon, Digitaria eriantha, Eragrostis obtusa, Setaria sphacelata and Sporobolus fimbriatus. Cynodon dactylon and S. sphacelata occurred more abundantly (p < 0.05) in the game reserves than in the other land management catergories. All the grass species had similar (p > 0.05) abundance along distance gradient from water points. Grass dry matter (GDM) showed significant differences (p < 0.05) between and within land management systems. However, GDM was not significantly affected by season, location of water point within each farm or reserve and distance along water points. Acacia karoo, Coddia rudis and Ehretia rigida were the most dominant woody species. Tree equivalent (TE) density of all encroaching woody plants combined was significantly (p < 0.05) higher on the communal area (1732 TE ha-1) than the commercial ranches (1136 TE ha-1) and game reserves (857 TE ha-1), but with no marked variations along distance from water points under all the land management systems. The electric conductivity (EC) was significantly (P < 0.01) higher in game reserves than in communal grazing areas and ranches. Soil organic matter percentage showed greatest and lowest values in the game reserves and commercial respectively. Soil pH and bulk density did not vary but soil organic matter (SOM), EC, bulk density and soil compaction were significant different with no increasing or decreasing trends. Soil properties were affected by herbivore pressure and trampling around water points with inconsistence magnitude and direction. In conclusion, grass species composition and GDM did not respond to distance from water points because either grazing gradient was absent or the length of transects was not enough to explain the absence or presence of gradients. High proportion of A. karoo and high densities of seedlings and saplings would seem as very good indicators of the woody vegetation changes in the different land management systems and distance from water points. The soil quality indicators around the water-points showed that livestock and game affected soil parameters.

This thesis examines the responses of non-indigenous pastoralists in Central Australian rangelands to two social movements that profoundly challenge their occupancy, use and management of land. Contemporary environmentalism and Aboriginal land rights have both challenged the status of pastoralists as valued primary producers and bearers of a worthy pioneer heritage. Instead, pastoralists have become associated with land degradation, biodiversity loss, and Aboriginal dispossession. Such pressure has intensified in the 1990s in the wake of the native Title debate, and various conservation campaigns in the arid and semi-arid rangelands. The pressure on pastoralists occur in the context of wider reassessment of the social and economic values or rangelands in which pastoralism is seen as having declined in value compared to ???post-production??? land uses. Reassessments of rangelands in turn are part of the global changes in the status of rural areas, and of the growing flexibility in the very meaning of ???rural???. Through ethnographic fieldwork among largely non-indigenous pastoralists in Central Australia, this thesis investigates the nature and foundations of pastoralists??? responses to these changes and critiques. Through memory, history, labour and experience of land, non-indigenous pastoralists construct a narrative of land, themselves and others in which the presence of pastoralism in Central Australia is naturalised, and Central Australia is narrated as an inherently pastoral landscape. Particular types of environmental knowledge and experience, based in actual environmental events and processes form the foundation for a discourse of pastoral property rights. Pastoralists accommodate environmental concerns, through advocating environmental stewardship. They do this in such a way that Central Australia is maintained as a singularly pastoral landscape, and one in which a European, or ???white???, frame of reference continues to dominate. In this way the domesticated pastoral landscapes of colonialism and nationalism are reproduced. The thesis also examines Aboriginal pastoralism as a distinctive form of pastoralism, which fulfils distinctly Aboriginal land use and cultural aspirations, and undermines the conventional meaning of ???pastoralism??? itself. The thesis ends by suggesting that improved dialogue over rangelands futures depends on greater understanding of the details and complexities of local relationships between groups of people, and between people and land.

Thesis (MScConsEcol (Conservation Ecology and Entomology))--Stellenbosch University, 2008.
In the Mediterranean climate regions of the world, agricultural practices have caused considerable landscape transformation and lead to introduction of alien species that now dominate secondary succession on abandoned agricultural fields. Various restoration attempts have been made to reduce alien plant species cover, and to enhance the re-establishment and cover of native plant species. However, results and successes were mostly short-term due to re-growth and persistence of the weedy alien species, which has been suggested to be caused by land use history, especially the nutrient enrichment of soil, and particularly phosphorus and nitrogen. This study investigated different soil properties (pH, electrical conductivity (EC), soil moisture, as well as available phosphorus (P) and total nitrogen (N)) on 10 and 20 year old abandoned fields, as a function of depth in three habitats (ridge (old cultivated area), ditch (old drainage line) and slope (intermediate zone between ridge and ditch)) on the old fields. The relationship between these soil properties and the vegetation occurring on the two old fields was established. At the same time, restoration treatments (autumn burn, combination of autumn burn and herbicide, herbicide application alone, as well as spring burn) were conducted to reduce the cover and abundance of non-native plant species and Cynodon dactylon, and to enhance cover of native species. Results from the study show that levels of all investigated soil properties were higher on the younger field. The highest difference was observed in EC and pH. Seasonal differences in both soil properties could also be observed. A principal component analysis indicated that the dynamic of all soil properties shaped the vegetation type on old fields, with the main soil properties being dependent on land-use history and time since abandonment. This study suggests that EC and pH could be part of parameters that drive the persistence of undesirable species persistence on old fields and inhibit native plant species instead.

Thesis (MScFor )--Stellenbosch University, 2003.
ENGLISH ABSTRACT: Species-rich Renosterveld vegetation does not return to old agricultural fields even after many years (10-20) of abandonment. In most cases the fields are slowly taken over by non-indigenous species, particularly alien pasture grasses and African lawn grass. While poor survival of indigenous seedlings due to competition, grazing or any other establishment constraints, might explain the failure of natural vegetation to colonise old fields, here I am testing the hypothesis that recolonisation by indigenous plant species is limited by seed dispersal. I have quantified changes in seed density with distance from the natural vegetation into old fields using seed traps and soil seed bank assessment. I have also looked at seed dispersal in the dung of large herbivores. Shrubs (with the exception of Eytropappus rhinocerotis) were poorly represented in the seed rain indicating that they might be seed limited. Dicerothamnus rinocerotis (a dominant shrub in Renosterveld) and certain geophytes (that were recovered in the soil bank) have proven that seed dispersal is not the primary constraint to their return to ploughed fields. Dicerothamnus rinocerotis produces a large number of seeds that are dispersed long distances into the old field and a number of geophytes were well represented in the soil bank. Large herbivores are dispersing a lot of herbaceous forbs in their dung but make very little contribution to the dispersal of indigenous tussock grass and shrubs. Seeds of indigenous Renosterveld tussock grasses (e.g Tribolium hispidum) were restricted to the edge of the natural vegetation. My research has shown that some indigenous seeds, particularly those dispersed in wind and through large mammals, do reach the old ploughed field. I therefore conclude that seed dispersal is not the primary constraint to the natural recovery of populations of some indigenous plant species on old fields, but may limit recovery of certain indigenous geophytes, grasses and shrubs.
AFRIKAANSE OPSOMMING: Spesie-ryke Renosterveld plantegroei hervestig nie op ou landerye nie, selfs ná baie jare (l0-20) van verlating. Oor die algemeen word hierdie grond stadig oorgeneem deur uitheemse spesies, veral uitheemse weidingsgrasse en kweekgras. Terwyl swak oorlewing van inheemse saailinge as gevolg van kompetisie, weiding of enige ander vestigingsbeperkinge, die mislukte vestiging van natuurlike plantegroei op ou benutte grond kan verduidelik, toets ek hier die hipotese dat hervestiging deur inheemse plantspesies deur saadverspreiding beperk word. Ek het veranderinge in saaddigtheid oor afstand vanaf die natuurlike plantegroei na ou landerye gekwantifiseer, deur gebruik te maak van saadopvangsvalle en sand saadbank beraminge. Ek het ook gekyk na saadverspreiding in die mis van groot herbivore. Struike (behalwe Eytropappus rhinocerotis) was swak verteenwoordig in die "saadreën", wat mag toon dat struike saadbeperk is. Eytropappus rhinocerotis ('n dominante struik in Renosterveld) en sekere geofiete (wat in die saadbank gevind is) het bewys dat saadverspreiding nie die hoofbeperking is vir hulle terugkeer na geploegde lande nie. Eytropappus rhinocerotis produseer 'n groot hoeveelheid saad wat oor groot afstande oor die ou landerye versprei word en 'n aantal geofiete was goed verteenwoordig in die saadbank. Groot herbivore versprei 'n groot hoeveelheid kruidagtige forbe in hulle mis, maar maak 'n baie klein bydrae tot die verspreiding van inheemse polgras en struike. Saad van inheemse Renosterveld polgrasse (bv. Tribolium hispidum) was beperk tot die some van die natuurlike plantegroei. My navorsing het getoon dat sommige inheemse saad, veral dié wat deur die wind en deur groot herbivore versprei word, wel die ou geploegde landerye bereik. Ek maak dus die gevolgtrekking dat saadverspreiding nie die hoofbeperking is vir die natuurlike herstel van populasies van sommige inheemse plantspesies op ou landerye nie, maar mag die herstel van sekere inheemse geofiete, grasse en struike beperk.

Temperate grasslands and the biodiversity they sustain are becoming increasingly imperilled. Habitat loss and degradation are considered primary causes of grassland species declines. Since livestock production is a dominant use of remaining temperate grassland, livestock producers and the grazing management decisions they make play a vital role in the recovery of grassland species. In this thesis, I examined social and ecological factors that drive habitat management and abundance of prairie wildlife species so as to contribute to conservation planning for prairie species at risk and their habitat. I focused on grassland songbirds because, of all prairie wildlife species, grassland birds have undergone some of the most dramatic declines in recent years. I employed an interdisciplinary approach, using theory and methodology from ornithology, rangeland management and the human dimension of conservation biology to achieve three objectives: i) to determine the extent to which indices of rangeland health explained variation in grassland songbird abundance for ten grassland bird species, including three species currently listed under Canada’s Species at Risk Act: Sprague’s pipit, McCown’s longspur and Chestnut-collared longspur; ii) to describe livestock producer characteristics, summarize producer awareness of and attitudes towards species at risk and the Canadian Species at Risk Act and evaluate how characteristics, awareness and attitudes affect producer willingness to engage in voluntary stewardship actions that support species at risk conservation; and iii) to explore relationships between select social and ecological factors and bird abundance for the three aforementioned grassland bird species at risk to elucidate novel pathways for achieving their conservation. I address the first objective in Chapter 2, where I identify the rangeland health index as a poor predictor of bird abundance and vegetation structure variables, such as litter and vegetation volume, as strong predictors of bird abundance. These findings make a case for further refining the rangeland health index as a tool for biodiversity assessment. In Chapter 3 I achieve the second objective and summarize producer characteristics, awareness and attitudes towards species. I also identify awareness, attitudes and rangeland management learning approach as important to producer willingness to support species at risk recovery. I accomplish the third objective in Chapter 4, where I present results of a structural equation model that upholds bird-habitat relationships identified in Chapter 2 and distinguishes management jurisdiction, size of land holdings and attitudes as important social factors to consider in conservation planning. Chapters 2 and 3 contribute to theory and methodology related to the ecological and social dimensions of grassland bird conservation, respectively. Chapter 4 demonstrates how structural equation models can be used to integrate social and ecological factors, and thereby inform habitat conservation and management. Both social and ecological data presented in this thesis make valuable contributions to producer engagement and habitat management aspects of conservation planning efforts for species at risk in the Milk River watershed of southwestern Saskatchewan. Overall, my findings point to the importance of a joint effort by regional private and public managers to use livestock grazing to create a mosaic of vegetation structure and habitat conditions suitable for the grassland bird community as a whole. This thesis provides a methodological approach that draws on and integrates social and ecological data, methods and concepts, thereby demonstrating how to conduct interdisciplinary research for biological conservation.

Ranching communities in Texas have long recognized fee hunting as a natural resource with the potential of directly affecting agricultural incomes. Hunting as an industry today, appears to be developing into an economic substitute for Texas ranchers who are accustomed to the variable nature of agricultural markets. To determine the economic impact of this market relative to its functional utilization by landowners, this research analyzed a large group of landowners in Central and South Texas. Information was collected through a personal interview process of 146 landowners. Data collected primarily related to the individual landowners' specific fee hunting operations and the economics associated with their enterprise operations. Response data was tabulated and examined through use of comparative analysis and bivariate methods when appropriate. Output yielded a descriptive demographic profile of landowners along with landowner opinion/attitude on ensuing constraints and values of enterprise operations. Additionally, costs and returns to operations were summarized through development of an enterprise budget by ecoregion. From this analysis, it became clear that many landowners possess strong 'feelings' about their lands and appear to share parallel ideologies relative to their properties as an earned entitlement and privilege to be passed along to their heirs. However, these Texas ranchers are well aware of the economic pressures under which they must operate and their commitment to sound land management practices increasingly includes wildlife management. This, much in part, is due to the dramatic increase in revenues generated by fee hunting enterprises over the past decade. However, the budget analysis indicates possible constraints when landownership size becomes smaller such as through the sale of parcels for business purposes or through inheritance.

The Ngorongoro Crater is a volcanic caldera located within the Ngorongoro Conservation Area in Tanzania. The Crater comprises a flat grassland plain surrounded by steep, bushy walls. It contains extremely high densities of animals and is ecologically the central feature of Ngorongoro Conservation Area. The management of the Ngorongoro Crater has changed significantly in recent times, with cattle being removed and fire excluded about 30 years ago. A detailed vegetation assessment was carried out in the Crater floor by Herlocker & Dirschl in 1972. Since then noticeable changes in vegetation structure and composition, with associated changes in wild herbivore numbers have occurred. The original vegetation survey was repeated in this study as accurately as possible using similar point-based techniques in order to quartify changes and form a baseline for management decision-making and future monitoring. In addition to repeating the vegetation survey, the standing biomass was estimated using a Pasture Disc Meter with associated calibration equations. Data were summarised using multivariate classification and ordination techniques in order to delineate six Homogenous Vegetation Units (HVUs) which can be used for management and management planning purposes, define transects and HVUs in terms of dominant species, describe the main species in relation to their occurrence in different associations and determine the fuel load of the standing crop. A key grass species technique was developed for rapid assessment of the Crater rangeland by the Ngorongoro Conservation Area staff who only need to be familiar with the dominant species. Bush surveys using a point centred quarter technique were conducted along transects in two distinct vegetation types, namely the Lerai Forest and Ngoitokitok Acacia xanthophloea forests and the lower caldera scrub vegetation. The data collected from these transacts were analysed to determine density and composition of the vegetation in the various height classes and the overall structure of the vegetation communities, A range monitoring system in conjunction with a controlled burning programme has been developed to provide an objective means of managing the- rangeland of the Ngorongoro Crater. Data revealed that changes have taken place in the vegetation, with a trend towards dominance by taller grasses and dominance by fewer species. Lack of fire has probably contributed to these changes. Reincorporating fire in the crater is recommended.
Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2006.

After European settlement, Australian rangelands especially in South Australia underwent significant changes because of the main land use of pastoralism. Many studies have revealed that the plant communities are negatively effected by herbivory mainly by sheep. The main aim of this study is to separate the different effects of sheep, rabbits and kangaroos. This was examined by survey supported by experimental and modelling research. A 32,000 km² area previously surveyed by Tiver and Andrew (1997) in eastern South Australia was re-surveyed to monitor populations of perennial plant species at sites of various intensity of grazing by sheep, rabbits and kangaroos (goats populations are low in the study area), the most important vertebrate herbivores. Plant population data were collected in both sheep paddocks and historically ungrazed by sheep (road reserves) by using the Random Walk method and analyzed using Generalized Linear Modelling (GLM) to separate the effects of sheep and rabbits on plant regeneration and their regeneration in response to grazing. These data were also compared to similar data collected by Tiver and Andrew in 1992 (1997) to ascertain if the reduction in rabbit numbers through introduction of RCV had allowed increased regeneration. Regeneration of many species inside paddocks were negatively affected and species in roadside reserves neither did not significantly increase from 1992 to 2004. However, some species showed increase of populations in spite of sheep grazing, with some species being less susceptible than others. This research also indicates kangaroo grazing impact on some plant species. Reduction in rabbit numbers following the 1995 release of calicivirus has not been effective in restoring regeneration. Another experiment was conducted at Middleback Field Station near Whyalla to identify herbivore grazing pressure on the arid zone plant species Acacia aneura using unfenced, sheep fenced and rabbit fenced grazing exclosures. This experiment was set up with seedlings in exclosures, ten replicates of each treatment, at plots four different distances from the watering point to identify the survivorship of seedlings. Data were collected by recording canopy volumes of seedling over an 18 month period and analyzed by Residual Maximal Likelihood (REML). Seedlings both near and far from the watering point were severely effected by large herbivores, either sheep, kangaroos or both, and in a separate experiment kangaroo grazing effects on the seedling were also identified. Seedlings browsed by the rabbits were recovered better than the seedlings grazed by the large herbivores. Decreasing kangaroo activities has been noticed when the rabbit movements increased. Computer modelling was conducted to predict the future plant population structure over 500 years using a matrix population model developed by Tiver et al. (2006) and using data collected in the survey as a starting point. Extinction probabilities of populations of Acacia aneura near watering points, far from watering points and under pulse grazing scenarios were compared. Sheep grazing was found to cause eventual extinction of populations in all parts of sheep paddocks. Together, the results indicate that sheep are the major herbivore suppressing regeneration of perennial plant species. Kangaroo and rabbits have an identifiable but lesser effect. The results have implications for conservation and pastoral management. To achieve ecological sustainability of arid lands a land-use system including a network of reserves ungrazed by sheep and with control of both rabbit and kangaroo numbers will be required.