The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Wayne L Linklater - One of the best experts on this subject based on the ideXlab platform.
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Black Rhinoceros avoidance of tourist infrastructure and activity planning and managing for coexistence
Oryx, 2021Co-Authors: Jeff R Muntifering, Wayne L Linklater, Pierre Du Preez, Robin Naidoo, Simson Uri Khob, Petrus Beytell, Shayne M Jacobs, Andrew T KnightAbstract:Wildlife-based tourism poses opportunities and challenges for species conservation. Minimizing potential negative impacts of tourism is critical to ensure business and conservation enterprises can coexist. In north-western Namibia tourism is used as a conservation tool for the Critically Endangered Black Rhinoceros Diceros bicornis. However, Black Rhinoceroses are susceptible to human disturbance and may become displaced by tourist activities, which threatens not only the security and health of the Rhinoceros population but also the sustainability of the business. We examined areas avoided by Black Rhinoceroses to understand how they respond to the type and extent of tourism development, and to evaluate management alternatives. We used spatial data on use of water sources by Rhinoceroses to create a series of a priori candidate models that described the negative influences of tourist activities on Rhinoceros habitat use. A model selection approach strongly supported a cumulative zones of influence model comprised of a 6 km buffer around the airstrip combined with a 1 km buffer around roads used daily. We compared alternative management scenarios using the best-performing model and found that an optimal road-use policy combined with airstrip relocation could minimize the total area avoided by the Black Rhinoceros to 7.1% and loss of high quality habitat to 20.7%. Under the worst-case scenario the area avoided and loss of high quality habitat were 153 and 85% greater, respectively, than under the scenario with optimal management. Our findings provide a novel framework and a practical, policy-relevant decision support tool to improve the contribution of tourism to wildlife conservation.
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lessons from a conservation and tourism cooperative the namibian Black Rhinoceros case
Annals of Tourism Research, 2020Co-Authors: Wayne L Linklater, Jeff R Muntifering, Shayne M Jacobs, Susan G Clark, Simson Urikhob, Elfrieda Hebach, Johann Cloete, Andrew T KnightAbstract:Abstract Wildlife-based tourism is widely promoted as a conservation tool, yet controversy surrounds its net contributions. Procedural problems are under-appreciated and originate from an under-attention to people: their interactions, values at play, and matters of special, shared, and common interests. We offer a case in Namibia of Black Rhinoceros conservation tourism that attended simultaneously and systematically to the inter-related ecological and social processes involved. We demonstrate how an understanding of social context and the decision making process developed, how outcomes were evaluated and synthesized lessons into prototypic elements as a pneumonic that we term the ‘ACE approach’: (1) establish an Arena for inclusive, open debate; (2) identify and use Conservation-oriented messaging; (3) adopt participatory Evidence-based management for action, feedback, and learning.
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effects of age and sex ratios on offspring recruitment rates in translocated Black Rhinoceros
Conservation Biology, 2018Co-Authors: Jay V Gedir, Peter R Law, Wayne L Linklater, Pierre Du PreezAbstract:Success of animal translocations depends on improving postrelease demographic rates toward establishment and subsequent growth of released populations. Short-term metrics for evaluating translocation success and its drivers, like postrelease survival and fecundity, are unlikely to represent longer-term outcomes. We used information theory to investigate 25 years of data on Black Rhinoceros (Diceros bicornis) translocations. We used the offspring recruitment rate (ORR) of translocated females-a metric integrating survival, fecundity, and offspring recruitment at sexual maturity-to detect determinants of success. Our unambiguously best model (AICω = 0.986) predicted that ORR increases with female age at release as a function of lower postrelease adult Rhinoceros sex ratio (males:females). Delay of first postrelease reproduction and failure of some females to recruit any calves to sexual maturity most influenced the pattern of ORRs, and the leading causes of recruitment failure were postrelease female death (23% of all females) and failure to calve (24% of surviving females). We recommend translocating older females (≥6 years old) because they do not exhibit the reproductive delay and low ORRs of juveniles (<4 years old) or the higher rates of recruitment failure of juveniles and young adults (4-5.9 years old). Where translocation of juveniles is necessary, they should be released into female-biased populations, where they have higher ORRs. Our study offers the unique advantage of a long-term analysis across a large number of replicate populations-a science-by-management experiment as a proxy for a manipulative experiment, and a rare opportunity, particularly for a large, critically endangered taxon such as the Black Rhinoceros. Our findings differ from previous recommendations, reinforce the importance of long-term data sets and comprehensive metrics of translocation success, and suggest attention be shifted from ecological to social constraints on population growth and species recovery, particularly when translocating species with polygynous breeding systems.
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standardising home range studies for improved management of the critically endangered Black Rhinoceros
PLOS ONE, 2016Co-Authors: Wayne L Linklater, Roan Plotz, Graham I H Kerley, James W GrecianAbstract:Comparisons of recent estimations of home range sizes for the critically endangered Black Rhinoceros in Hluhluwe-iMfolozi Park (HiP), South Africa, with historical estimates led reports of a substantial (54%) increase, attributed to over-stocking and habitat deterioration that has far-reaching implications for rhino conservation. Other reports, however, suggest the increase is more likely an artefact caused by applying various home range estimators to non-standardised datasets. We collected 1939 locations of 25 Black rhino over six years (2004–2009) to estimate annual home ranges and evaluate the hypothesis that they have increased in size. A minimum of 30 and 25 locations were required for accurate 95% MCP estimation of home range of adult rhinos, during the dry and wet seasons respectively. Forty and 55 locations were required for adult female and male annual MCP home ranges, respectively, and 30 locations were necessary for estimating 90% bivariate kernel home ranges accurately. Average annual 95% bivariate kernel home ranges were 20.4 ± 1.2 km2, 53 ±1.9% larger than 95% MCP ranges (9.8 km2 ± 0.9). When home range techniques used during the late-1960s in HiP were applied to our dataset, estimates were similar, indicating that ranges have not changed substantially in 50 years. Inaccurate, non-standardised, home range estimates and their comparison have the potential to mislead Black rhino population management. We recommend that more care be taken to collect adequate numbers of rhino locations within standardized time periods (i.e., season or year) and that the comparison of home ranges estimated using dissimilar procedures be avoided. Home range studies of Black rhino have been data deficient and procedurally inconsistent. Standardisation of methods is required.
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Black Rhinoceros demography should be stage not age based
African Journal of Ecology, 2014Co-Authors: Peter R Law, Wayne L LinklaterAbstract:Biologically meaningful and standardized definitions of life stages are essential for demographic studies, especially for endangered and intensively managed species such as Rhinoceros. Focusing on the Black Rhinoceros Diceros bicornis, we argue that standardized biological definitions of calf, subadult, and adult, rather than age classes, provide the appropriate basis for Black Rhinoceros demography. Age classes do not correlate well with the risks of mortality nor characterize, at least for females, the attainment of reproductive maturity. Black Rhinoceros demography based on age classes, typical of existing literature, obscures the significance of studies of mortality and fecundity. Comparison of studies also requires standardized definitions. We propose biologically meaningful definitions of life stages appropriate for the demography of the Black Rhinoceros and encourage the community of Rhinoceros researchers to reach consensus on standardized, demographically appropriate definitions for adoption for each Rhinoceros species.
O J B Huebschle - One of the best experts on this subject based on the ideXlab platform.
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vaccine induced protection against anthrax in cheetah acinonyx jubatus and Black Rhinoceros diceros bicornis
Vaccine, 2004Co-Authors: P C B Turnbull, B W Tindall, J D Coetzee, C M Conradie, R L Bull, P M Lindeque, O J B HuebschleAbstract:Abstract Institution of a policy of vaccination in endangered species with a vaccine not previously administered to it cannot be undertaken lightly. This applies even more in the case of cheetah (Acinonyx jubatus) with their unusually monomorphic gene pool and the potential restrictions this places on their immune responses. However, the recently observed mortalities from anthrax in these animals in the Etosha National Park, Namibia, made it imperative to evaluate vaccination. Black Rhinoceros (Diceros bicornis), another endangered species in the park, have been vaccinated for over three decades but the effectiveness of this has never been evaluated. Passive protection tests in A/J mice using sera from 12 cheetahs together with enzyme immunoassay indicated that cheetah are able to mount seemingly normal primary and secondary humoral immune responses to the Sterne 34F2 live spore livestock vaccine. Overall protection rates in mice injected with the sera rose and fell in concert with rises and declines in antibody titres, although fine analysis showed that the correlation between titre and protection was complex. Once a high level of protection (96% of mice 1 month after a second booster in the cheetahs) had been achieved, the duration of substantial protection appeared good (60% of the mice 5 months after the second booster). Protection conferred on mice by sera from three of four vaccinated rhino was almost complete, but, obscurely, none of the mice receiving serum from the fourth rhino were protected. Sera from three park lions with naturally acquired high antibody titres, included as controls, also conferred high levels of protection. For the purposes of wildlife management, the conclusions were that vaccination of cheetah with the standard animal anthrax vaccine causes no observable ill effect in the animals and does appear to confer protective immunity. At least one well-separated booster does appear to be desirable. Vaccination of rhino also appears to be justified from the limited data obtained.
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vaccine induced protection against anthrax in cheetah acinonyx jubatus and Black Rhinoceros diceros bicornis
Vaccine, 2004Co-Authors: P C B Turnbull, B W Tindall, J D Coetzee, C M Conradie, R L Bull, P M Lindeque, O J B HuebschleAbstract:Institution of a policy of vaccination in endangered species with a vaccine not previously administered to it cannot be undertaken lightly. This applies even more in the case of cheetah (Acinonyx jubatus) with their unusually monomorphic gene pool and the potential restrictions this places on their immune responses. However, the recently observed mortalities from anthrax in these animals in the Etosha National Park, Namibia, made it imperative to evaluate vaccination. Black Rhinoceros (Diceros bicornis), another endangered species in the park, have been vaccinated for over three decades but the effectiveness of this has never been evaluated. Passive protection tests in A/J mice using sera from 12 cheetahs together with enzyme immunoassay indicated that cheetah are able to mount seemingly normal primary and secondary humoral immune responses to the Sterne 34F2 live spore livestock vaccine. Overall protection rates in mice injected with the sera rose and fell in concert with rises and declines in antibody titres, although fine analysis showed that the correlation between titre and protection was complex. Once a high level of protection (96% of mice 1 month after a second booster in the cheetahs) had been achieved, the duration of substantial protection appeared good (60% of the mice 5 months after the second booster). Protection conferred on mice by sera from three of four vaccinated rhino was almost complete, but, obscurely, none of the mice receiving serum from the fourth rhino were protected. Sera from three park lions with naturally acquired high antibody titres, included as controls, also conferred high levels of protection. For the purposes of wildlife management, the conclusions were that vaccination of cheetah with the standard animal anthrax vaccine causes no observable ill effect in the animals and does appear to confer protective immunity. At least one well-separated booster does appear to be desirable. Vaccination of rhino also appears to be justified from the limited data obtained.
William V Holt - One of the best experts on this subject based on the ideXlab platform.
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non invasive assessment of oestrous cycles and evaluation of reproductive seasonality in the female wild Black Rhinoceros diceros bicornis minor
Reproduction, 2002Co-Authors: J N Garnier, William V Holt, P F WatsonAbstract:Female wild Black Rhinoceroses in Zimbabwe were monitored non-invasively using faecal progesterone metabolite analysis and observation of reproductive behaviour. A postpartum period of reproductive inactivity of at least 4 months, followed by a period of 4‐7 months of oestrous cyclicity, was detected in six multiparous females. Threequarters of the oestrous cycles ( n= 21) had a total duration (mean ± SEM) of 26.8 ± 1 days. Other types of cycle were characterized either by an extended luteal phase, lasting on average twice as long as the normal cycle, or by an extended follicular phase. These extended cycles may have resulted from early embryo loss and heat stress. Female Rhinoceroses did not conceive before 8 months after giving birth and some females ( n= 2) most likely aborted after 3.0‐3.5 months of gestation. The detected period of cyclic oestrus occurred between May and March in females ( n= 9), and there was a 3 month extended interoestrous interval in nulliparous females during the period of decreasing daylengths that can be presumed to be the period of poorest fertility for the Black Rhinoceros under tropical latitudes. In contrast, the period of optimum fertility in the Southern hemisphere coincided with the late spring and early summer, and corresponded to the early rainy season. As a result, a higher incidence of births was detected in the late rainy season, providing the lactating female with the most suitable environment in terms of nutritional requirements.
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non invasive diagnosis of pregnancy in wild Black Rhinoceros diceros bicornis minor by faecal steroid analysis
Reproduction Fertility and Development, 1998Co-Authors: J N Garnier, Daphne I Green, A R Pickard, H J Shaw, William V HoltAbstract:The objective of this study was to determine whether faecal progestagen measurement could be used to diagnose pregnancy in wild Black Rhinoceros cows. Immunoreactive 20α-progestagens were measured in faecal samples collected regularly (one or two times times per week) from pregnant and non-pregnant wild Black Rhinoceros females (n =6) in Zimbabwe. Fresh dung piles deposited by the study animals were serially sampled during prolonged periods of tracking with local game scouts. Samples were stored frozen, and dried prior to methanol extraction. Immunoreactivity in faecal extracts was measured with a 20α-dihydroprogesterone enzyme immunoassay and was shown to reflect circulating progesterone concentrations. Mean concentrations of faecal 20α-progestagens during each month of gestation were significantly higher than faecal concentrations in non-pregnant animals (P<0.05), except during the second month of gestation. Faecal 20α-progestagens remained 5–10 times higher than concentrations in non-pregnant animals from the 4th to 15th month of gestation. It was concluded that regular non-invasive reproductive monitoring of Black Rhinoceros in the wild was possible and that pregnancy could be accurately diagnosed from the measurement of 20α-progestagens in faecal samples. The use of this technique in wild Black Rhinoceros populations will offer new perspectives for in situ management of this endangered species.
Benoit Goossens - One of the best experts on this subject based on the ideXlab platform.
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substantial molecular variation and low genetic structure in kenya s Black Rhinoceros implications for conservation
Conservation Genetics, 2011Co-Authors: Shadrack Muya, Michael William Bruford, B Okitaouma, Anne W T Muigai, Z B Osiemo, E Mwachiro, Benoit GoossensAbstract:Kenya’s Black Rhinoceros population declined by more than 98% from 20,000 individuals in the 1970s to around 400 individuals in 1990 due to the effects of poaching, at which time the surviving individuals were isolated in a series of demographically inviable subpopulations. An initial management exercise translocated the survivors into four high security sanctuaries to control poaching and enhance breeding, and this measure successfully arrested the decline. Subsequently, new sanctuaries were established and the metapopulation size reached 650 animals by 2008. However, translocations and the current management strategy that partitions the metapopulation into ‘montane’ and ‘lowland’ Rhinoceros may have substantial consequences at the population level and their impact on population genetic diversity has not been investigated. In this study, 12 of the 16 extant subpopulations were analysed using 408 bp of mitochondrial control region sequence (n = 170) and nine microsatellite loci (n = 145). Both markers detected moderate to high genetic diversity (h = 0.78 ± 0.027, n = 170; HO = 0.70 ± 0.087, n = 145) consistent with previous studies on Diceros bicornis michaeli. However, mtDNA and nDNA diversity varied substantially between subpopulations. The results suggest that the Masai Mara is more differentiated, inbred and isolated than other subpopulations. It also suggests that there are neither distinct montane and lowland groups nor other detectable historical barriers to gene flow. Instead the large majority of genetic diversity was partitioned at the level of individuals; highlighting the need to conserve as many individuals as possible. Future translocations should consider the genetic profile of individuals and the demographic history of both the donor and recipient subpopulations.
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mating system and reproductive skew in the Black Rhinoceros
Molecular Ecology, 2001Co-Authors: Julie Garnier, Michael William Bruford, Benoit GoossensAbstract:Only ≈ 2600 Black Rhinoceros survive today, mainly in small, isolated populations of < 100 animals. The management of remaining Black Rhinoceros populations aims at preserving natural levels of genetic relatedness and optimizing breeding success, which requires an accurate knowledge of the mating system, reproductive skew and effective population size. DNA was extracted from faecal samples from a community of 35 wild Black Rhinoceros, and microsatellites were used to characterize patterns of paternity of 19 offspring born from eight females in this community. Paternity could be ascribed unequivocally for each offspring. Although our conclusions must be considered tentative, we present the first genetic evidence that Black Rhinoceros males are polygynous, with a high variance in reproductive success. We also describe a noninvasive management tool that can be used for the genetic management of this critically endangered species, both in the wild and in captivity.
P C B Turnbull - One of the best experts on this subject based on the ideXlab platform.
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vaccine induced protection against anthrax in cheetah acinonyx jubatus and Black Rhinoceros diceros bicornis
Vaccine, 2004Co-Authors: P C B Turnbull, B W Tindall, J D Coetzee, C M Conradie, R L Bull, P M Lindeque, O J B HuebschleAbstract:Abstract Institution of a policy of vaccination in endangered species with a vaccine not previously administered to it cannot be undertaken lightly. This applies even more in the case of cheetah (Acinonyx jubatus) with their unusually monomorphic gene pool and the potential restrictions this places on their immune responses. However, the recently observed mortalities from anthrax in these animals in the Etosha National Park, Namibia, made it imperative to evaluate vaccination. Black Rhinoceros (Diceros bicornis), another endangered species in the park, have been vaccinated for over three decades but the effectiveness of this has never been evaluated. Passive protection tests in A/J mice using sera from 12 cheetahs together with enzyme immunoassay indicated that cheetah are able to mount seemingly normal primary and secondary humoral immune responses to the Sterne 34F2 live spore livestock vaccine. Overall protection rates in mice injected with the sera rose and fell in concert with rises and declines in antibody titres, although fine analysis showed that the correlation between titre and protection was complex. Once a high level of protection (96% of mice 1 month after a second booster in the cheetahs) had been achieved, the duration of substantial protection appeared good (60% of the mice 5 months after the second booster). Protection conferred on mice by sera from three of four vaccinated rhino was almost complete, but, obscurely, none of the mice receiving serum from the fourth rhino were protected. Sera from three park lions with naturally acquired high antibody titres, included as controls, also conferred high levels of protection. For the purposes of wildlife management, the conclusions were that vaccination of cheetah with the standard animal anthrax vaccine causes no observable ill effect in the animals and does appear to confer protective immunity. At least one well-separated booster does appear to be desirable. Vaccination of rhino also appears to be justified from the limited data obtained.
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vaccine induced protection against anthrax in cheetah acinonyx jubatus and Black Rhinoceros diceros bicornis
Vaccine, 2004Co-Authors: P C B Turnbull, B W Tindall, J D Coetzee, C M Conradie, R L Bull, P M Lindeque, O J B HuebschleAbstract:Institution of a policy of vaccination in endangered species with a vaccine not previously administered to it cannot be undertaken lightly. This applies even more in the case of cheetah (Acinonyx jubatus) with their unusually monomorphic gene pool and the potential restrictions this places on their immune responses. However, the recently observed mortalities from anthrax in these animals in the Etosha National Park, Namibia, made it imperative to evaluate vaccination. Black Rhinoceros (Diceros bicornis), another endangered species in the park, have been vaccinated for over three decades but the effectiveness of this has never been evaluated. Passive protection tests in A/J mice using sera from 12 cheetahs together with enzyme immunoassay indicated that cheetah are able to mount seemingly normal primary and secondary humoral immune responses to the Sterne 34F2 live spore livestock vaccine. Overall protection rates in mice injected with the sera rose and fell in concert with rises and declines in antibody titres, although fine analysis showed that the correlation between titre and protection was complex. Once a high level of protection (96% of mice 1 month after a second booster in the cheetahs) had been achieved, the duration of substantial protection appeared good (60% of the mice 5 months after the second booster). Protection conferred on mice by sera from three of four vaccinated rhino was almost complete, but, obscurely, none of the mice receiving serum from the fourth rhino were protected. Sera from three park lions with naturally acquired high antibody titres, included as controls, also conferred high levels of protection. For the purposes of wildlife management, the conclusions were that vaccination of cheetah with the standard animal anthrax vaccine causes no observable ill effect in the animals and does appear to confer protective immunity. At least one well-separated booster does appear to be desirable. Vaccination of rhino also appears to be justified from the limited data obtained.