Jonathan Cranidge Lovett

Selection of line-transect methods for estimating the density of group-living animals: lessons from the primates.

We review the four major contemporary methods for estimating density of group‐living animals from line‐transect sampling: perpendicular modelling of group centers, perpendicular modelling of center of measurable individuals, strip transects and animal–observer distance. The efficacy of each method is evaluated to produce a simple selection guide. We review the literature and use field data from the Udzungwa Mountains, Tanzania. The review is relevant to all group‐living animals; however, examples are drawn from the primates. Perpendicular methods have better mathematical justification than non‐perpendicular methods. For perpendicular methods using detection function models, it is preferable to measure group location using center of measurable individuals, as group centers are hard to estimate. The assumptions of detection function models are often broken in poor visibility habitats or with unhabituated animals. Alternatively strip transects may be used where there are reliable data on group spread and/or visibility. Strip transects are also the most practical, along with the animal–observer method; however, the latter lacks mathematical justification. We conclude that there are arguments for continued use of all four methods. In certain situations the use of raw encounter rates may also be considered. The appropriate method is determined by minimizing bias and considering time, resources and field conditions. Am. J. Primatol. 70:452–462, 2008.

Multiple objectives in biofuels sustainability policy

Sustainability, with its multiple environmental, economic and social objectives, is now prominent in many national and international policies. These are implemented in a classical incrementalist approach. We use the example of biofuels to demonstrate the way that multiple objectives are developed in energy and environmental policy. Biofuels are promoted as replacements for transport fuels, but biofuel policy is also geared towards socio-economic goals such as agricultural subsidy and strategic goals such as security of energy supply. We discuss examples of multiple objectives and regulatory instruments applied to biofuels with a focus on the United Kingdom and highlight the difficulties of applying sustainability criteria under international trade agreements. In conclusion we briefly contrast biofuels policy against that of fossil fuels.

Carbon emissions: dry forests may be easier to manage.

Debate on the carbon-credit system known as REDD (‘reducing emissions from deforestation and forest degradation’) has focused on technical and methodological obstacles and on sourcing carbon finance. The impact of the system on the world’s 350 million tropical forest dwellers calls for closer scrutiny. Without careful planning, REDD stands to create large numbers of ‘carbon refugees’ as governments curb financially unrewarding deforesting activities such as those of small-scale agriculturalists and fuel-wood harvesters, who mostly pay no taxes on what they produce. Forest dwellers could become excluded from their means of subsistence to preserve carbon. A similar situation has occurred during previous attempts to conserve tropical forests. Last year I worked in Liberia’s forests bordering Ivory Coast, and heard of park guards in the Tai National Forest, a well-protected Ivorian biodiversity conservation area, shooting local hunters dead. I met Ivorian subsistence hunters, excluded from their ancestral lands, relocating to Liberia to maintain their livelihoods. The journal Conservation & Society is investigating the possible displacement of thousands of people in Africa by biodiversity conservation projects. The Centre for International Forestry Research has shown that forest-based sources of income generated by local communities are often rendered illegal by forest law. Crackdowns tend to target the poor, rather than the criminal networks behind the estimated 50% of global tropicaltimber exports that are illegal. A REDD-inspired redoubling of current efforts at law enforcement would further victimize forestdependent peoples. Forest dwellers should be seen as an important part of the solution to deforestation. Evidence from 80 forest commons in 10 countries shows that community ownership, larger forest areas and a high degree of community autonomy in decision-making are all associated with both high carbon storage and livelihood benefits. Conversely, local users with insecure property rights extract resources at unsustainable rates (A. Chhatre and A. Agrawal Proc. Natl Acad. Sci. USA 106, 17667–17670; 2009). Extending legal collective property rights to forest users over large areas, combined with forest-encroachment monitoring by independent scientists and local agencies, could reduce deforestation without human rights violations. This plan may substantially reduce deforestation by cutting off the supply of ‘empty’ land for outsiders to deforest. There is good will on the ground for REDD to work, with safeguards. With transfers of US

A handbook of environmental management

10 billion a year under discussion, the REDD agreement should ensure that at least 50% of carbon payments go directly to forest dwellers, and that their property rights are assured. Otherwise, some of the world’s most marginalized people will end up paying a high price for reducing carbon emissions. Simon L. Lewis Earth and Biosphere Institute, School of Geography, University of Leeds, Leeds LS2 9JT, UK e-mail: s.l.lewis@leeds.ac.uk King Canute and the wisdom of forest conservation

The biological importance of the Eastern Arc Mountains of Tanzania and Kenya

A Handbook of Environmental Management presents a range of case studies that demonstrate the complementary application of different social science techniques in combination with ecology-based management thinking to the natural environment. Contemporary environmental management is characterised by an increasing awareness of the need for interdisciplinary approaches. This requires managers to effectively combine insights from both the natural and social sciences in order to ensure sustainable outcomes. This eloquent and unique Handbook provides a broad overview, complimented by specific case studies and techniques that are used in environmental management from the local level to international environmental regimes. With contributions from leading authorities in the field, this innovative volume provides a valuable teaching aid for students, as well as an insightful and practical reference tool for environmental practitioners with no background in the social sciences. Environmental managers and policymakers attempting to learn about, and integrate thinking from, the social sciences should also not be without this important resource.