IUCN / SSC Cat Specialist Group - Digital Cat Library |
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| Perez, I. | |
| Estimating the Arabian leopard (_Panthera pardus nimr_) population size in Israel using fecal DNA | |
| 2003 Full Book | |
The population of leopards in the Judean desert and the Negev highlands is part of a critically endangered subspecies, the Arabian leopard (_Panthera pardus nimr_), which occurs in Oman, the United Arab Emirates, Saudi Arabia, Yemen and Israel. Only about 100 individuals occur in the wild. The expansion of land-use that has accompanied human population growth has caused fragmentation of this subspecies' natural habitat. Because of natural low population densities and their solitary life style, leopards are extremely sensitive to the loss and fragmentation of their natural habitat. The isolation of small subpopulations might cause the loss of potential sources of immigrants, leading to close inbreeding and its concomitant deleterious effects, and might in turn increase the extinction probability of these isolated populations. This highly endangered subspecies is subject to intensive conservation efforts in the United Arab Emirates and Oman which include captive breeding programs. An eighteen-year study of the Judean desert population was conducted by Giora Ilani until the late 1980's, but the Negev population was never studied and the number of individuals in the wild was never determined. The main purpose of the present study was to estimate the population size both in the Judean desert and the Negev highlands. Knowing the population size of the Arabian leopard in Israel will assist in the formulation of an effective management program to save the subspecies from becoming locally extinct. Feces were systematically collected along the main gorges frequently used by leopards over two years. Various molecular analyses were implemented at the level of the species, population and individuals on DNA extracted from the feces. Such non-invasive sampling allows genetic studies of free-ranging animals wihtout the need to capture or even observe them, and increases the chances of obtaining a large enough sample. Fecal DNA was typed for several microsatellite loci to deduce the number of unique multilocus genotypes in the population. The power of multilocus genotypes for identifying individuals was quantified for individual loci by calculating the probability of identity (PI). This estimator evaluates the probability that two individuals, drawn at random from a population, will have the same genotype at multiple loci. Assuming that each unique genotype represents a different leopard, the population size was projected as the asymptote of a rarefaction curve, describing the cumulative number of unique multilocus genotypes as a function of the number of feces typed. In addition, the sex of each DNA sample was determined using specific markers of both the sex-chromosomes. During this study, 54 leopard DNA samples were obtained, in different locations in the study area. Integrating the molecular analysis data with the spatial distribution of the locations where the feces were found, enabled discrimination of eight different individuals: a male and a female in the Judean desert, and two females and four males in the Arava and the Negev highlands. the microsatellite typing results revealed very low genetic variability and many loci were found monomorphic, implying close inbreeding and genetic drift, which are typical in very small populations. Three individuals had identical multilocus genotypes, such that only geographic and sex data made it possible to discern among them. The population size analysis estimated that there are seven unique genotypes in the wild population. This study provides the first estimate of the size of the Arabian leopard population in Israel using genetic data. Although leopards were never seen during this study, their feces provided answers to questions that would usually require direct observation and handling of animals. Considering the low genetic variation found, the population might benefit from the introduction of individuals from related populations for genetic restoration. The results also have conservation implications; the presence of five males and three female leopards gives good reason for optimism for an increase in the size of this small population. |
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