Impacts of free-roaming dogs on native biodiversity

Project Number
NParks-Impacts of free-roaming dogs

Project Duration
November 2015 - October 2019


Singapore has lost more than 95% of her primary vegetation over the past 200 years (Corlett 1997). Not surprisingly, 34 to 87% of the native vertebrates went extinct following the drastic land use changes, not including the “living dead” (i.e., long-lived species with tiny existing population; Brook et al. 2003). One of the better known extirpations is the textbook example of the last tiger (Panthera tigris) that was killed in the 1930s. It is now widely recognised that apex consumers like tigers can exert profound effects on the lower trophic levels of the food web and have landscape-wide influences — a concept formalised as “trophic cascades” (Paine 1980). One mechanism through which trophic cascades can occur is mesopredator release (Crooks and Soulé 1999), whereby medium-sized consumers, which were originally controlled by top-down predation pressure, could now increase in numbers and cause changes in the lower trophic levels in the absence of top predators. With increasing human population and land use changes, nature reserves in Singapore are never too far away from human developments and are constantly subjected to accompanying “edge effects” (see Murcia 1995). One such edge effect is the influx of introduced species like domestic dogs. Based on anecdotal reports and unpublished data, free-roaming dogs were documented in many parts of Central Catchment Nature Reserves (CCNR) and Sungei Buloh Wetlands Reserve (SBWR).

Funding Source
James Gan, Deputy Director, Wildlife Management Research

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