Human land use and patterns of parasitism in tropical amphibian hosts

Landscape alterations by humans can change patterns of parasite transmission. Depending on the type alteration and the life histories of parasites and hosts, parasitism may increase or decrease. To investigate whether parasitism in tropical amphibians was associated with land use change, I studied three species of amphibians, Rana vaillanti, Eleutherodactylus fitzingeri, and Smilisca puma from the Province of Heredia, Costa Rica, in the Atlantic lowlands. Frogs were collected and examined for parasites during the rainy seasons of 2001-2003 from sites in forest or clear-cut cattle pastures. The abundances of five species of parasites and parasite species richness of R. vaillanti were significantly higher in pasture habitat. A single parasite species shared by E. fitzingeri and S. puma showed a trend of increased abundance in pasture habitats. Overall, the abundances of six parasite species (three trematodes, an intestinal nematode, an encysted nematode, and a filarial nematode) were higher in pastures, while two species (trematodes) were higher in forest. This study suggests that land use activities in tropical regions affects the abundance and richness of amphibian parasites. Converting forest to pasture may impact the abundance of amphibian parasites because subsequent water quality changes (e.g. eutrophication, higher pH) often enhance habitat and resources for intermediate hosts (e.g. snails, mosquitoes) involved in parasite life cycles. Aquatic amphibians (e.g. R. vaillanti) may be particularly prone to experiencing increases in parasitism in agricultural habitats due to the positive relationship between many aquatic intermediate hosts and water quality changes associated with agricultural land use.     

Assessing risks of disease transmission between wildlife and livestock: The Saiga antelope as a case study

Disease transmission between wildlife and livestock can undermine conservation efforts, either by challenging the viability of threatened populations, or by eroding public tolerance of actual or potential wildlife disease reservoirs. This paper describes the use of transmission models to assess the risk of disease transfer across the wildlife-livestock boundary, and to target control strategies appropriately. We focus on pathogens of the Saiga antelope (Saiga tatarica) and domestic ruminants in Central Asia. For both foot and mouth disease and gastrointestinal nematodes, the main risk is associated with infection of saigas from livestock, and subsequent geographical dissemination of infection through saiga migration. The chance of this occurring for foot and mouth disease is predicted to be highly dependent on saiga population size and on the time of viral introduction. For nematodes, the level of risk and predicted direction of transmission are affected by key parasite life history traits, such that prolonged off-host survival of Marshallagia in autumn enables infection of saigas and transfer northwards in spring. Field estimates of parasite abundance provide qualitative support for model predictions. The application of models as tools for the early evaluation of disease transmission between wildlife and livestock is discussed.     

Design and management of continental wildlife reserves: Lessons from the everglades

Evidence from the attempt to preserve wading birds in Everglades National Park suggests that application of biogeographic theory to design and management of continental wildlife reserves requires considerations additional to those previously proposed. Shape and areal extent alone are inadequate criteria for reserve design. Unlike islands, continental reserves are not necessarily self-contained ecosystems driven by endogenous processes. The isolation of a continental reserve may lead to a phenomenon of ecosystem degeneration, the extent and rapidity of which depends on the ecological condition of adjacent habitat. Management strategies to preserve maximum species richness are seldom totally acceptable and often inherently unattainable. Conflicts between species management and ecosystem management illustrate the need for instituting an array of management strategies on a regional basis for preservation of both endangered species and ecosystems.     

Lizard assemblage and reserve size and structure in the Western Australian wheatbelt — some implications for conservation

Twenty-three reserves in the Western Australian wheatbelt were examined in detail to evaluate the adequacy of the reserve system in the region for the conservation of lizards. We recorded most of the lizard species known from the region and conclude that the reserve system is at present adequate for their conservation.Lizard species richness in wheatbelt reserves does not appear to be related to isolation from adjacent uncleared land, either in space or time, but is related to the ecology of the reserve. Lizard species richness-area relationships for wheatbelt reserves are very similar to the most comparable late-Pleistocene/Holocene continental island lizard faunas; the slopes of the regression lines are not significantly different and the intercepts are only marginally significant.Multiple regression analysis shows that 75% of the variation observed in lizard species richness between reserves is accounted for by the algorithm of the number of vegetation associations on these reserves; addition of other reserve variables examined (including area) does not significantly increase this explained variation.Reserves as small as 30 ha are valuable as sanctuaries for lizards although it is suggested that 1500 ha is an optimum size. Some vegetation formations are more important for lizards than others; woodlands are most important.     

Free-ranging domestic dogs (Canis familiaris) as predators and prey in rural Zimbabwe: threats of competition and disease to large wild carnivores

Domestic dogs (Canis familiaris) arrived in Zimbabwe ca. 1000 years ago. Numbers of free-ranging dogs have reached unprecedented levels in communal lands (agro-pastoralist rural areas), and interact with large wild carnivores along boundaries with wildlife reserves as predators and prey. This study examined a population of 236 dogs in a 33-km² section of Gokwe Communal Land (GCL) bordering the Sengwa Wildlife Research Area (SWRA) in north-western Zimbabwe in 1995-1996. Dogs were found up to 6 km within the SWRA, and were the most common carnivore on the GCL-SWRA boundary. Observations of 16 radio-collared dogs showed that they were inefficient predators. Only 20 kills were recorded amongst the remaining dog population, of which three were wild ungulates. Dogs were unsuccessful predators due to their small group size (mean 1.7) and body mass (mean 14.7 kg), and the abundance of alternative food. It is therefore unlikely that they compete with large carnivores for wild prey. However, leopards (Panthera pardus), lions (P. leo) and spotted hyaenas (Crocuta crocuta) preyed on dogs in GCL, removing ?6% of the dog population in 1993. Such predation provides ideal circumstances for disease transmission. Canid disease was prevalent in the study area; including rabies and probably distemper. The risk of infection is greatest during the dry season (May-October), when peaks in rates of disease, carnivore incursions into GCL, and predation on dogs coincided. The role of jackals (Canis adustus and Canis mesomelas) and spotted hyaena predation of dogs is discussed in relation to disease epidemics within wildlife reserves. With a dog population growth rate of 6.5% per annum, and the prevalence of canid diseases, the conservation threat posed by dogs is escalating on communal land-wildlife reserve boundaries in Zimbabwe. Measures to control dog numbers and improve vaccination coverage of dogs are discussed.     

Effects of the introduced parasite Philornis downsi on nestling growth and mortality in the medium ground finch (Geospiza fortis)

Invasive species have the potential to detrimentally affect native ecosystems by out competing or directly preying upon native organisms, and have been implicated in the extinction of endemic populations. One potentially devastating introduced species in the Galápagos Islands is the parasitic fly Philornis downsi. As larvae, P. downsi parasitize nestling birds and have been associated with high nestling mortality and reduced growth rates. Here I document nestling growth and mortality in a bimodal population of the medium ground finch, Geospiza fortis. Observations were conducted over three years, and under variable ecological conditions. Annual parasite prevalence in nests ranged from 64% to 98%, and nestling mortality in nests with parasites ranged from 16% to 37%. Parasite load and parasite load per nestling follow a skewed distribution with many nests having relatively few parasites, and few nest having many. Parasite load, however, was not correlated with onset of breeding, clutch size, the number of nestlings, nestling survival or fledgling success. Parasite load per nestling, on the other hand, was correlated with clutch initiation date and the proportion of nestlings that died in parasitized nests. Neither nestling size nor growth rate differed between parasitized and unparasitized nests. In addition, male and female beak morphology was not correlated with parasite load, breeding variables or nestling survival. Thus, while overall mortality due to parasitism is high, ecological conditions and possible host defenses may potentially counter some of the detrimental affects of P. downsi on nestling size and growth. These results taken together suggest that parasitism of P. downsi larvae on nestling G. fortis has the potential to lead to large population declines.     

The effect of agri-environment schemes on amphibian diversity and abundance

The Western Peat District of The Netherlands has a characteristic Dutch landscape. It consists mainly of meadows for dairy farming, crisscrossed by a dense network of ditches. Its biodiversity is regarded as of high national and international importance, but is declining as a result of intensive farming. Besides the establishment of reserves, measures to conserve and restore biological diversity have been implemented in the form of agri-environment schemes (AES). The aim of this research is to investigate, first, whether the reserves, assuming these provide source populations, affect the distribution of amphibians and, second, whether AES in the form of nature-friendly ditch bank management benefits amphibian diversity and abundance and enhances distribution across the agricultural landscape. In total, 42 ditches (24 control ditches and 18 AES ditches) were studied. Each ditch was perpendicular to the boundary of one of the reserves and was divided into five ditch sections of 100 m spread over 800 m, starting in the reserve and proceeding into the farmland. Generalized Linear Modelling was used to quantify the effect of nature-friendly ditch bank management (AES) and distance to the nature reserve on amphibian diversity and abundance. Species richness was high in AES ditches as compared to control ditches. The number of observed green frog (Rana esculenta synkl.) seemed to decline in the control ditches at large distances from the reserve. The other species, although their abundances were higher in the reserves, did not show a declining trend across the farmland. However, all adult amphibians except green frogs together had significantly higher abundances in the AES ditches compared to the control ditches. These results illustrate the potential role of agricultural ditches, combined with reserves and nature-friendly ditch bank management, in the conservation of amphibian populations.     

Birds in Western Australian wheatbelt reserves—implications for conservation

Bird species richness in 22 reserves in the Western Australian wheatbelt was shown to be related not to isolation from adjacent uncleared land, either spatially or with time since clearing of land in their vicinity, but to area of reserve and certain reserve habitat variables. The nature of these relationships was examined with multiple regression analysis. Reserve area was the most important variable, except in some passerine groups, where numbers of plant species, vegetation associations, and plant life form and density classes in each vegetation stratum were, separately, more important than area. Eighty-two percent of the variation in the number of bird species was explained by area of reserve and number of plant species, indicating the importance of floristics to the total bird assemblage within reserves. The number of formations present (the broadest vegetation structural grouping used) did not explain any of the variation in species numbers in any of the bird groupings.There were more resident passerine species present in wheatbelt reserves than there were breeding passerine species on similar-sized southwestern Australian late-Pleistocene/Holocene islands, although the species versus area relationship of the resident habitat-specific passerines (P₅ group) was very similar to that of the island land-bird faunas. The P₅ species group contained many species which probably responded to wheatbelt reserves as islands; some of these species may fail to persist in the wheatbelt in the long term. Twenty-three species usually resident in reserves and 15 ‘non-residents’ were identified as being ‘vulnerable’ or of uncertain conservation status in the wheatbelt.Some vegetation formations within reserves were more important to birds than others; woodlands were most important both to resident and transient species. Most species do not appear to distinguish between shrublands and heaths as major habitats; Species richness versus formation area relationship suggest that insular patchiness for birds in the wheatbelt was manifest at the level of vegetation formations. Reserves as small as 80 ha were important sanctuaries for birds in the wheatbelt, although 1500 ha was considered a minimum area of reserve to conserve a local avifauna. Reserves of the order of 30,000–94,000 ha were required to contain most of the avifauna of the wheatbelt.     

Effects of agricultural landscape and pesticides on parasitism in native bullfrogs

Native amphibian populations are shrinking worldwide, and both parasitic infections and environmental stress from agriculture have been implicated. We investigated the principal hypothesis that environmental by-products of agricultural activity mediate parasitism in native frogs. Bullfrogs were collected from wetlands with variable landscape disturbance and water quality and examined for helminth parasites. We predicted that pesticide pollution and landscape development would be significant factors shaping the parasite communities and populations. Parasite diversity and species richness were lower in wetlands impacted by both pesticides and land use. Two parasite groups, direct life-cycle nematodes and echinostomes, were common in polluted habitats, potentially increasing frog pathology and mortality risk. In areas with agricultural landscape and reduced forest cover, parasite diversity and species richness were low, perhaps because of less parasite transmission from birds and mammals. This result suggests that land development limits terrestrial vertebrate access to wetlands. Our results indicate that parasite abundance and community structure in wetlands are influenced by factors operating locally within the wetland and more broadly in the surrounding landscape. We suggest that parasite communities in amphibians are effective indicators of ecosystem health and animal biodiversity, and thus useful tools for conservation biology.     

Population viability, ecological processes and biodiversity: Valuing sites for reserve selection

No-take reserves constitute one tool to improve conservation of marine ecosystems, yet criteria for their placement, size, and arrangement remain uncertain. Representation of biodiversity is necessary in reserve planning, but will ultimately fail for conservation unless factors affecting species’ persistence are also incorporated. This study presents an empirical example of the divergent relationships among multiple metrics used to quantify a site’s conservation value, including those that address representation (habitat type, species richness, species diversity), and others that address ecological processes and viability (density and reproductive capacity of a keystone species, in this case, the black chiton, Katharina tunicata). We characterized 10 rocky intertidal sites across two habitats in Barkley Sound, British Columbia, Canada, according to these site metrics. High-richness and high-production sites for K. tunicata were present in both habitat types, but high richness and high-production sites did not overlap. Across sites, species richness ranged from 29 to 46, and adult K. tunicata varied from 6 to 22 individuals m⁻². Adult density was negatively correlated with species richness, a pattern that likely occurs due to post-recruitment growth and survival because no correlation was evident with non-reproductive juveniles. Sites with high adult density also contributed disproportionately greater potential reproductive output (PRO), defined by total gonad mass. PRO varied by a factor of five across sites and was also negatively correlated with species richness. Compromise or relative weighting would be necessary to select valuable sites for conservation because of inherent contradictions among some reserve selection criteria. We suspect that this inconsistency among site metrics will occur more generally in other ecosystems and emphasize the importance of population viability of strongly interacting species.     

Diversity patterns in butterfly communities of the Greek nature reserve Dadia

Traditionally, nature reserves have been centered mainly around areas that are important for vertebrate diversity. This practice has not gone unchallenged and may be a suboptimal choice for overall conservation planning. To investigate this problem, we sampled butterfly species richness in a nature reserve in north eastern Greece that was originally established for the protection of birds of prey. Patterns of butterfly species richness and abundance were investigated by means of transect walks across a range of the seven predominant habitat types (wet and dry meadow, pine, oak and mixed forest, grazed, and agricultural land). Data analysis, including ANOVA and DCA (detrended correspondence analysis), revealed that the main gradients in butterfly species richness (low to high) were from sites dominated by the pine forest matrix of the core areas of the reserve, to peripheral sites in landscapes of mixed or oak forest, and from sites with little human impact to more disturbed areas with high grazing pressure. Species of conservation interest were concentrated at sites of low human impact. Ten of them are endemic to Europe and/or threatened in Europe. In this respect, the most important species are Lycaena ottomanus, Thymelicus acteon, and Pseudophilotes vicrama which are declining all over Europe. Our results suggest that (1) traditional agricultural practices in areas surrounded by forest can be considered as important management tools in butterfly conservation, (2) highest butterfly species richness is found in the periphery of the reserve rather than in the core areas, and (3) for butterfly conservation the zones surrounding the strictly protected areas are equally important as the core areas.     

The impact of marine reserves on nekton diversity and community composition in subtropical eastern Australia

The effectiveness of marine reserve protection on the biodiversity of aquatic assemblages (i.e. nekton) in subtropical eastern Australia was examined within two small (<6 km²) marine reserves and four non-reserve areas. The two marine reserves, and their corresponding non-reserves, were located in different geographical locations within Moreton Bay (north and south) and sites were surveyed with multiple hauls of a seine net. Species richness, evenness, density and mean size of the inshore communities were compared between the reserves and non-reserves. No statistical significant difference was detected in species richness between the areas however species evenness was significantly lower in the only non-reserve site impacted by commercial net fishing. Mean size of nekton was found to be significantly greater in the marine reserves compared to non-reserves but no statistical significant difference was found in the density of nekton between the study sites. Multivariate analysis revealed differences in community composition, particularly between the geographical locations where areas were impacted by different types of fishing pressure (recreational v commercial). These results highlight the impact commercial fishing can have on entire nekton assemblages, not just on targeted species. Our study demonstrates that the small marine reserves in Moreton Bay are protecting marine biodiversity and are thus at least partially achieving their management objective (to enhance the zone’s marine biodiversity).     

Conservation in a city: Do the same principles apply to different taxa?

Factors shaping overall species richness and representation of endangered species of vascular flora and butterflies were determined in 48 nature reserves in Prague, Czech Republic. Total species richness of both groups, and the presence of endangered butterflies, reflect the present status of habitats, while that of endangered plants reflects habitat composition at the time of reserve establishment. Reserve area has a much stronger effect on the species richness of sessile plants than mobile butterflies which, especially endangered species, respond more positively to heterogeneity than to area. Both species richness and endangered species peak in reserves half covered with forest, likely because they harbor species of both woodland and non-woodland habitats, and edge specialists. Solely relying on area and disregarding habitat quality, or a failure to conserve small but high quality sites, may be counterproductive for conserving endangered plant and butterfly species. To conserve diversity of plants and butterflies current management practices, often aimed at maintaining large blocks of pre-selected plant communities, should change to include maintenance of fallows, edges and transient zones.     

The island dilemma: Lessons of modern biogeographic studies for the design of natural reserves

A system of natural reserves, each surrounded by altered habitat, resembles a system of islands from the point of view of species restricted to natural habitats. Recent advances in island biogeography may provide a detailed basis for understanding what to expect of such a system of reserves. The main conclusions are as follows:The number of species that a reserve can hold at equilibrium is a function of its area and its isolation. Larger reserves, and reserves located close to other reserves, can hold more species.If most of the area of a habitat is destroyed, and a fraction of the area is saved as a reserve, the reserve will initially contain more species than it can hold at equilibrium. The excess will gradually go extinct. The smaller the reserve, the higher will be the extinction rates. Estimates of these extinction rates for bird and mammal species have recently become available in a few cases.Different species require different minimum areas to have a reasonable chance of survival.Some geometric design principles are suggested in order to optimise the function of reserves in saving species.     

Restoration of plant diversity on ditch banks: Seed and site limitation in response to agri-environment schemes

Recently it has become clear that seed limitation is probably a much more important factor in plant recovery than has often been recognized. However, in practice, restoration measures that are focussed on decreasing site limitation may actually increase seed limitation. We tried to determine whether the effects of restoration measures affect site or seed limitation or both. An experiment was set up on ditch banks in the Netherlands which applied agri-environment schemes (AES). To investigate whether nature reserves (seed source) can improve species diversity on the surroundings and to what extent AES is improving this function, we studied the plant diversity (presence of individual species and species richness) of ditch bank vegetations in relation to increasing distance from nature reserves. The presence or absence and species richness of 25 target plants were assessed in 26 ditch banks with AES and 36 non-AES at 15 plots each differing in distance to a nature reserve. Data were analyzed using a Hierarchical Generalized Linear Model (HGLM) with species richness and presence of individual species as response variables and distance to nature reserve and application of AES as factors, controlling for possible confounding factors. Results were interpreted as the effects of AES on seed and site limitation of the species. The results showed that plant diversity decreased significantly with distance from source populations. There were considerable differences in species diversity between AES and non-AES ditch banks, with the former showing greater plant diversity especially in the first 200 m from nature reserves. Presences of all individual species decreased with distance to nature reserve, but the strength of this relationship and the AES effects differed among species. AES ditch banks had lower site limitations for most plant species, but did not have lower seed limitation.     

Plant community functional shifts in response to livestock grazing in intermountain depressional wetlands in British Columbia, Canada

Wetlands are ecologically and economically important ecosystems with high conservation value. Although wetland vegetation is strongly determined by abiotic factors, grazing disturbance may also be an important influence on this community. We evaluated the effects of livestock grazing on wetland vegetation in marsh and wet meadow zones in intermountain depressional wetlands in the southern interior of British Columbia, Canada. We sampled marshes and wet meadows in 36 wetlands along a grazing intensity gradient ranging from fully fenced and ungrazed wetlands to unfenced wetlands heavily grazed by livestock. The amount of bare ground was used as a surrogate measure of the intensity of livestock grazing. Vegetation community structure and composition was strongly associated with grazing intensity. Increased livestock grazing favored shorter-lived and smaller plants; conversely, the frequency of tall and rhizomatous species, which constitute the dominant plant species in these systems, declined with higher livestock use. The effects of grazing were more pronounced in the marsh than in the wet meadow. Associations between species richness and grazing differed between zones: native and exotic species richness showed a unimodal response in the marsh while in the wet meadow exotic richness increased and native richness showed no response. The relationship between exotic frequency and grazing was also inconsistent between zones, with a negative association in the marsh and a positive but weak association in the wet meadow. Grazing-related changes in vegetation along the grazing intensity gradient were substantial and may affect the habitat value of these wetlands for dependent wildlife such as breeding waterfowl.     

The conservation value for mammals of reserves in the western Australian wheatbelt

Twenty-three reserves in the Western Australian wheatbelt were examined in an attempt to assess their conservation value for native mammals, excluding bats. Multiple regression analysis on log transformed data showed that 72% of the observed variation in mammal species richness between reserves was accounted for by reserve size. The addition of the other reserve variables examined did not increase significantly this explained variation, although significant correlations existed with most variables. Estimates suggest that a minimum reserve area of about 40,000 ha is required to conserve that part of the regional assemblage of mammals in southern and western Australia likely to persist in the face of moderate disturbances by man and his agencies. Reserves should have large areas of major vegetation formations and maximise the number of regional vegetation associations. Nature reserves as small as 30 ha are valuable sanctuaries for certain species of native mammals.Comparison with mammal faunas isolated on islands by Quaternary glacioeustatic sea-level rise shows that in relation to area, wheatbelt reserves are richer in species, but the slopes of the regressions are similar, particularly for those islands that are little disturbed by man and introduced predators. We suggest that most of the species of mammals surviving in the wheatbelt are suited to existing within patches of vegetation, such as nature reserves, because they are adapted to surviving within the natural archipelago of soil and vegetation types which characterise the wheatbelt and southwestern Western Australia. We suggest that the species of mammals that have become extinct in the wheatbelt are those that are unable to cope with alteration in environmental patchiness caused by changes in the pattern of fires resulting from European occupation.     

Matching species with reserves - uncertainties from using data at different resolutions

I address the problem of the mismatch between the spatial resolution of data for species and reserves. Such mismatch may help to recognise variability in species recording in reserves. Using distribution data from 10 × 10 km grid cells for angiosperms, bryophytes, pteridophytes in Portugal, I investigate how mapping rules used to assign reserve coverages to grid cells would affect estimates of species representation in reserves. It was found that the estimated representation of species would be greatly affected by variation in the mapping rules used. The range of expected representation of species in reserves would vary from a minimum of 30% for bryophytes to a maximum of 63% for angiosperms. Current reserve networks would always represent fewer angiosperms than expected by chance; depending on the rules, more or fewer bryophytes than expected by chance; and slightly more, or just as many, pteridophytes as expected by chance. These results call for the need to assess sensitivity of reserve selection and evaluation procedures to data and decision-rules, without which it may be difficult to assess the effectiveness of reserves to represent biodiversity.     

The effects of habitat connectivity on cryptogam richness in boulder metacommunity

We investigated the effects of habitat patch size and connectivity on cryptogam richness on 288 calcareous boulders. The studied boulders were found to be a particularly suitable ‘metacommunity model system’ and allowed comparison of species richness among cryptogams with differing substrate specificity, life history and red list status. The dependence of species richness on boulder surface area was modelled using Arrhenius power model, and contrasts were analysed between connected and isolated boulders. Species richness was clearly related to boulder size, but the rates of increase of species richness with increasing boulder area (z-values) were highly variable among species groups. Highest value of z (1.17) was found for species with large propagules, and values around 0.5 were obtained for calciphilous and regionally red-listed species and z = 0.42 for perennials. The lowest value of z (0.27) occurred in calcicolous species while for all species, colonists, and species with small propagules the values were 0.3-0.4. The richness of all species was 11% higher on connected than isolated boulders, while connected boulders had 31% more of both calcicolous and regionally red-listed species and 19% more of colonists. The result suggests that in the investigated system that boulder size is a crucial determinant of cryptogam richness, and their spatial configuration in terms of connectivity may further contribute to cryptogam richness. The latter result lends support to the importance of metacommunity processes for the maintenance of cryptogam richness.     

Factors affecting the success of translocations of the black-faced impala in Namibia

This study analysed 21 translocations of the vulnerable black-faced impala (Aepyceros melampus petersi) to 20 Namibian game farms that occurred between 1970 and 2001, seeking characteristics of the translocated populations and the release sites that significantly correlated with the success of the translocations. Characteristics considered were: initial population size; presence of cheetah and leopard; area; habitat type; occurrence within the historical range of the subspecies and occurrence of trophy hunting. Success of translocations was described by whether the population had a positive growth rate. The success rate of translocations of black-faced impala (62%) was higher than shown in other studies of vertebrate translocations. Initial population size was paramount to the success of translocations. Releases of larger populations were more likely to lead to positive population growth rates than were releases of small populations. The presence of cheetah also influenced the success of translocated populations. In the presence of cheetah, small populations translocated to game farms were significantly less likely to be viable than larger populations. Recommendations for the management of this vulnerable antelope include introducing large initial populations, ideally more than 15 animals, rather than attempting to eliminate cheetah following translocations of impala.