Burrow fractal dimension and foraging success in subterranean rodents: a simulation

For animals that forage underground, the success with which food items are located may be closely related to burrow architecture. Fractal dimension, which describes how a burrow explores the surrounding area in a way that is independent of burrow length, is an obvious choice for a single metric describing burrow shape. Although it is often assumed that burrows of high fractal dimension will be associated with greater foraging success, this has not previously been demonstrated. In this study, we use computer simulations to study the success with which burrows of different fractal dimensions locate randomly distributed food items. In addition, we examine the effect of different patterns of food distribution (in particular the patchiness with which food items are distributed) and consider how using different criteria for locating food items affects the relationship between fractal dimension and foraging success. We conclude that, under a wide range of plausible assumptions about the ways in which subterranean rodents forage, burrows of high fractal dimension are more successful at locating food items than burrows of lower fractal dimension. Copyright 2006.burrow architecture; computer model; food distribution; food patchiness; shape

Ecological and financial impacts of illegal bushmeat trade in Zimbabwe

Under conditions of political instability and economic decline illegal bushmeat hunting has emerged as a serious conservation threat in Zimbabwe. Following settlement of game ranches by subsistence farming communities, wildlife populations have been eradicated over large areas. In several areas still being managed as game ranches illegal hunting is causing further declines of wildlife populations (including threatened species such as the wild dog Lycaon pictus and black rhinoceros Diceros bicornis), threatening the viability of wildlife-based land uses. From August 2001 to July 2009 in Save´ Valley Conservancy 10,520 illegal hunting incidents were recorded, 84,396 wire snares removed, 4,148 hunters caught, 2,126 hunting dogs eliminated and at least 6,454 wild animals killed. Estimated future financial losses from illegal hunting in the Conservancy exceed USD 1.1 million year-1. Illegal hunters’ earnings account for 0.31–0.52% of the financial losses that they impose and the bushmeat trade is an inefficient use of wildlife resources. Illegal hunting peaks during the late dry season and is more frequent close to the boundary, near areas resettled during land reform and close to water. Illegal hunting with dogs peaks during moonlight periods. Our study highlights several management and land-use planning steps required to maximize the efficacy of anti-poaching and to reduce the likelihood of high impacts of illegal hunting. Anti-poaching efforts should be aligned with the regular temporal and spatial patterns of illegal hunting. Leases for hunting and tourism concessions should ensure minimum adequate investment by operators in anti-poaching. Reserve designers should minimize the surface area to volume ratio of parks. Fences should not be constructed using wire that can be made into snares. Land reform involving game ranches should integrate communities in wildlife-based land uses and ensure spatial separation between land for wildlife and human settlement. Means are required to create stakeholdings for communities in wildlife and disincentives for illegal hunting.TRAFFIC Southern and East Africa, the European Union, Wilderness Trust, Chicago Board of Trade and the supporters of the African Wildlife Conservation Fund.http://journals.cambridge.orgab201

Dynamics and underlying causes of illegal bushmeat trade in Zimbabwe

The prevalence and impacts of the illegal trade in bushmeat are under appreciated in Southern Africa, despite indications that it constitutes a serious conservation threat in parts of the region. Bushmeat trade has emerged as a severe threat to wildlife conservation and the viability of wildlife-based land uses in Zimbabwe during a period of political instability and severe economic decline. We conducted a study around Save´ Valley Conservancy in the South-East Lowveld of Zimbabwe to investigate the dynamics and underlying causes of the bushmeat trade, with the objective of developing solutions. We found that bushmeat hunting is conducted mainly by unemployed young men to generate cash income, used mostly to purchase food. Bushmeat is mainly sold to people with cash incomes in adjacent communal lands and population centres and is popular by virtue of its affordability and availability. Key drivers of the bushmeat trade in the South-East Lowveld include: poverty, unemployment and food shortages, settlement of wildlife areas by impoverished communities that provided open access to wildlife resources, failure to provide stakes for communities in wildlife-based land uses, absence of affordable protein sources other than illegally sourced bushmeat, inadequate investment in anti-poaching in areas remaining under wildlife management, and weak penal systems that do not provide sufficient deterrents to illegal bushmeat hunters. Each of these underlying causes needs to be addressed for the bushmeat trade to be tackled effectively. However, in the absence of political and economic stability, controlling illegal bushmeat hunting will remain extremely difficult and the future of wildlife-based land uses will remain bleak.TRAFFIC East/Southern Africa, the European Union, the German Federal Ministry for Economic Cooperation and Development, Wilderness Trust, Chicago Board of Trade, and the supporters of the African Wildlife Conservation Fund.http://journals.cambridge.orgab201