Abstract
Concerns about vulnerability of mammalian carnivores to extinction, especially on small islands, appear to conflict with prior reports of endemic populations of leopard cat Prionailurus bengalensis (Kerr, 1792) surviving in agricultural landscapes on oceanic islands. We investigated the persistence of the Visayan leopard cat (P. b. rabori) in the sugarcane fields on Negros, an oceanic island in central Philippines. A population remained throughout the year at our study site on a sugarcane farm, and reproduction was noted. Non-native rodents form the bulk of the cat diet, followed by reptiles, birds, amphibians, and insects. Prey species identified from the samples commonly occur in agricultural areas in the Philippines. Prey composition did not vary significantly with respect to wet and dry season, or sugarcane harvest cycle. This study provides evidence that an intensively managed agricultural landscape on this oceanic island supports a native obligate carnivore that subsists primarily on exotic rats. This study supports a prior prediction that leopard cats will show flexibility in prey selection on islands with few or no native small mammal prey species, but in this case they do so not by switching to other vertebrates and invertebrates, but rather to exotic pest species of rodents.
Highlights
Because of their high trophic level, high metabolism, and low population density, mammalian carnivores are considered to be among the organisms most vulnerable to extinction, often due to fragmentation of habitat or over-hunting (e.g., Primack 1993)
The purpose of this study was to investigate the diet of wild leopard cats inhabiting a sugarcane farm on Negros Island to determine if they remain as a resident population on the farm throughout the year, reproduce on the farm, and subsist on exotic rats, as suggested by earlier studies
Three bird kills were found in the study area; we cannot be certain that they were attributable to leopard cats, but this was likely because tracks and feces of leopard cats were found nearby
Summary
Because of their high trophic level, high metabolism, and low population density, mammalian carnivores are considered to be among the organisms most vulnerable to extinction, often due to fragmentation of habitat or over-hunting (e.g., Primack 1993). That study highlighted what appears to be an incongruity with prior reports of a small native felid, the leopard cat Prionailurus bengalensis (Image 1), maintaining populations on several small oceanic islands, including Tsushima (696km2) and Iriomote (289km2) in Japan. Most populations of this cat occur on islands of 1000km or larger, where at least seven species of native small mammals (Soricomorpha plus Rodentia) are present. The study showed that on the two Japanese islands, leopard cats consumed large amounts of non-mammalian prey (e.g., birds, reptiles, amphibians, crustaceans, and insects) Their persistence on such small islands was evidence of versatility in feeding habits where close competitors, especially small carnivores of the family Viverridae, are absent (Watanabe 2009)
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