John G. Robinson

Body size, diet, and population density of Neotropical forest mammals

The population densities of Neotropical mammalian species are predictably related to their body masses and diets. In interspecific comparisons, population densities generally declined with increasing body mass, and declined with body mass within each of seven specified dietary categories. In our regression analyses, body mass alone accounted for approximately half of the variation in density in the general case, and a greater proportion of the variation in five of the regressions within dietary categories. Pairwise comparisons using stepwise multiple regression indicated that adding diet as well as body mass significantly increased the proportion of variance explained. Finally, the magnitude of the effect of body mass on population density varied with dietary class. These results indicate that, in general, larger-bodied species occur at lower densities than smaller-bodied species, and species with restricted diets and those at higher trophic levels occur at lower densities than species whose diet allows them access to a greater abundance of food resources. The decline in density with increasing body size is greater within some dietary categories than others. The results broadly support the hypothesis that population densities of species are determined by the potential resources, and ultimately energy, available to them in specified habitats.

Bringing the Tiger Back from the Brink—The Six Percent Solution

The Tiger Summit, to be hosted by Prime Minister Vladimir Putin in Russia in November 2010—the Chinese Year of the Tiger and the International Year of Biodiversity—promises to be the most significant meeting ever held to discuss the fate of a single non-human species. The Summit will culminate efforts by the Global Tiger Initiative (GTI), launched in 2008 by Robert Zoellick, World Bank President. Leaders of 13 tiger range states, supported by international donors and conservationists attending the summit, are being asked to commit to substantive measures to prevent the unthinkable: extinction of the worlds last wild tiger populations. Wild tiger numbers are at an historic low. There is no evidence of breeding populations of tigers in Cambodia, China, Vietnam, and DPR Korea. Current approaches to tiger conservation are not slowing the decline in tiger numbers [1]–[3], which has continued unabated over the last two decades. While the scale of the challenge is enormous, we submit that the complexity of effective implementation is not: commitments should shift to focus on protecting tigers at spatially well-defined priority sites, supported by proven best practices of law enforcement, wildlife management, and scientific monitoring. Conflict with local people needs to be mitigated. We argue that such a shift in emphasis would reverse the decline of wild tigers and do so in a rapid and cost-efficient manner.

Having your wildlife and eating it too: An analysis of hunting sustainability across tropical ecosystems

Unsustainable hunting of wildlife or bushmeat for human consumption across the tropics threatens both wildlife populations and the livelihoods of people who depend on these resources. The probability that hunting can be sustainable depends in part on ecological conditions that affect the ‘supply’ of and ‘demand’ for wildlife resources. In this study, supply is estimated across a number of tropical ecosystem types by calculating the theoretical ‘maximum sustainable offtake’ in kg/km 2 for harvestable wildlife. Demand is estimated from observed harvests in kg/km 2 . We examine how supply and demand vary across relatively undisturbed ecosystems, indexed by annual rainfall. Supply is potentially highest in dry forests and wetter savannah grasslands and decreases in moist forests and more xeric grasslands. Demand tends to exceed supply in moist forests and xeric grasslands. Analogous to this ecological variation along the rainfall gradient is the gradient created by the conversion of tropical forests by humans. We hypothesise that the wild meat supply is greater in secondary forests and forest–farm–fallow mosaics than in undisturbed forests and test this with available data. We conclude that the probability that hunting will be sustainable varies with ecosystem type and degree of human disturbance and should influence where land is zoned for protected areas and where for wildlife harvests.

Towards Wildlife Management in Tropical Forests

Hunting is ubiquitous in tropical forests around the world, and meat from wildlife species is an important source of animal protein for rural populations. Ungulates, primates, and rodents provide most of the biomass consumed, but a wide variety of wildlife species are limited for both subsistence and commerce. Across the tropics, tens of millions of animals and millions of metric tons of meat are hunted and consumed each year. Is this harvest sustainable? Available information and the use of simple sustainability models suggest it is not. The supply of wildlife is limited, a anmal production of large mammals in tropica forests is low when compared to other ecosystems, The demand is increasing as tropical forests become more accessible to hunters, effective human population densities increase, people become more sedentary, traditional hunting practices change, the meat trade becomes more commercial, and demand increases for wild meat from urban centers. If wildlife populations are to be sustained, then management institutions, be they government or community-based, need to be strengthened.

Invasives: A Major Conservation Threat

A flurry of recent articles call upon the conservation community to embrace invasive species. Davis and coauthors propose down-sizing the struggle against invasives ([ 1 ][1]). In the News Focus story “Embracing invasives” (18 March, p. [1383][2]), G. Vince suggests that the Galapagos “

What Does It Mean to Successfully Conserve a (Vertebrate) Species

The conservation of species is one of the foundations of conservation biology. Successful species conservation has often been defined as simply the avoidance of extinction. We argue that this focus, although important, amounts to practicing conservation at the “emergency room door,” and will never be a sufficient approach to conserving species. Instead, we elaborate a positive definition of species conservation on the basis of six attributes and propose a categorization of different states of species conservation using the extent of human management and the degree to which each of the attributes is conserved. These states can be used to develop a taxonomy of species “recovery” that acknowledges there are multiple stable points defined by ecological and social factors. “With this approach, we hope to contribute to a new, optimistic conservation biology that is not based on underambitious goals and that seeks to create the conditions under which Earths biological systems can thrive.

A Collaboratively-Derived Science-Policy Research Agenda

The need for policy makers to understand science and for scientists to understand policy processes is widely recognised. However, the science-policy relationship is sometimes difficult and occasionally dysfunctional; it is also increasingly visible, because it must deal with contentious issues, or itself becomes a matter of public controversy, or both. We suggest that identifying key unanswered questions on the relationship between science and policy will catalyse and focus research in this field. To identify these questions, a collaborative procedure was employed with 52 participants selected to cover a wide range of experience in both science and policy, including people from government, non-governmental organisations, academia and industry. These participants consulted with colleagues and submitted 239 questions. An initial round of voting was followed by a workshop in which 40 of the most important questions were identified by further discussion and voting. The resulting list includes questions about the effectiveness of science-based decision-making structures; the nature and legitimacy of expertise; the consequences of changes such as increasing transparency; choices among different sources of evidence; the implications of new means of characterising and representing uncertainties; and ways in which policy and political processes affect what counts as authoritative evidence. We expect this exercise to identify important theoretical questions and to help improve the mutual understanding and effectiveness of those working at the interface of science and policy.

SEASONAL ANOINTMENT WITH MILLIPEDES IN A WILD PRIMATE: A CHEMICAL DEFENSE AGAINST INSECTS?

Members of a wild group of wedge-capped capuchin monkeys (Cebus olivaceus) intentionally anoint themselves with millipedes (Orthoporus dorsovittatus). Chemical analysis revealed these millipedes secrete two benzoquinones, compounds known to be potently repellent to insects. We argue that the secretion that rubs off on the monkeys in the course of anointment provides protection against insects, particularly mosquitoes (and the bot flies they transmit) during the rainy season. Millipede secretion is so avidly sought by the monkeys that up to four of them will share a single millipede. The anointment must also entail risks, since benzoquinones are toxic and carcinogenic. We suggest that for capuchins the immediate benefits of anointment outweigh the long-range costs.

Measuring the sustainability of hunting in tropical forests.

Wild animals are an important source of protein for the rural peoples living in or near tropical forests. However, the resource can easily be overexploited and game species can become locally depleted, or even extinct. This paper discusses attempts to measure the sustainability of hunting in tropical forests. It examines five indices of sustainability in current use and two models that attempt to model sustainability.

Common and Conflicting Interests in the Engagements between Conservation Organizations and Corporations

The conservation community increasingly views the corporate sector as a positive force for conservation. Collaborations between corporations and nongovernmental conservation organizations (NGOs) seek to mitigate the negative effects of corporate activities and augment positive conservation outcomes. I reviewed the establishment of corporate social responsibility (CSR) policies by corporations; the emerging focus on environmental practices and sustainability; and the history of engagement between corporations and nongovernmental organizations. I considered the ethical and reputation vulnerabilities of these collaborations, which depend especially on the financial nature of the relationship and reviewed how CSR approaches have influenced corporate practices. I concluded that whereas CSR practices can act to mitigate negative environmental impact, to date they have had limited positive effect on biodiversity conservation.