Andrew Balmford

Reconciling Food Production and Biodiversity Conservation: Land Sharing and Land Sparing Compared

Protecting the largest possible area of natural habitats while growing food on the smallest area can reconcile food production with conservation. The question of how to meet rising food demand at the least cost to biodiversity requires the evaluation of two contrasting alternatives: land sharing, which integrates both objectives on the same land; and land sparing, in which high-yield farming is combined with protecting natural habitats from conversion to agriculture. To test these alternatives, we compared crop yields and densities of bird and tree species across gradients of agricultural intensity in southwest Ghana and northern India. More species were negatively affected by agriculture than benefited from it, particularly among species with small global ranges. For both taxa in both countries, land sparing is a more promising strategy for minimizing negative impacts of food production, at both current and anticipated future levels of production.

Global mapping of ecosystem services and conservation priorities

Global efforts to conserve biodiversity have the potential to deliver economic benefits to people (i.e., “ecosystem services”). However, regions for which conservation benefits both biodiversity and ecosystem services cannot be identified unless ecosystem services can be quantified and valued and their areas of production mapped. Here we review the theory, data, and analyses needed to produce such maps and find that data availability allows us to quantify imperfect global proxies for only four ecosystem services. Using this incomplete set as an illustration, we compare ecosystem service maps with the global distributions of conventional targets for biodiversity conservation. Our preliminary results show that regions selected to maximize biodiversity provide no more ecosystem services than regions chosen randomly. Furthermore, spatial concordance among different services, and between ecosystem services and established conservation priorities, varies widely. Despite this lack of general concordance, “win–win” areas—regions important for both ecosystem services and biodiversity—can be usefully identified, both among ecoregions and at finer scales within them. An ambitious interdisciplinary research effort is needed to move beyond these preliminary and illustrative analyses to fully assess synergies and trade-offs in conserving biodiversity and ecosystem services.

Sustainable Intensification in Agriculture: Premises and Policies

Clearer understanding is needed of the premises underlying SI and how it relates to food-system priorities. Food security is high on the global policy agenda. Demand for food is increasing as populations grow and gain wealth to purchase more varied and resource-intensive diets. There is increased competition for land, water, energy, and other inputs into food production. Climate change poses challenges to agriculture, particularly in developing countries (1), and many current farming practices damage the environment and are a major source of greenhouse gases (GHG). In an increasingly globalized world, food insecurity in one region can have widespread political and economic ramifications (2).

Preserving the evolutionary potential of floras in biodiversity hotspots

One of the biggest challenges for conservation biology is to provide conservation planners with ways to prioritize effort. Much attention has been focused on biodiversity hotspots. However, the conservation of evolutionary process is now also acknowledged as a priority in the face of global change. Phylogenetic diversity (PD) is a biodiversity index that measures the length of evolutionary pathways that connect a given set of taxa. PD therefore identifies sets of taxa that maximize the accumulation of ‘feature diversity’. Recent studies, however, concluded that taxon richness is a good surrogate for PD. Here we show taxon richness to be decoupled from PD, using a biome-wide phylogenetic analysis of the flora of an undisputed biodiversity hotspot—the Cape of South Africa. We demonstrate that this decoupling has real-world importance for conservation planning. Finally, using a database of medicinal and economic plant use, we demonstrate that PD protection is the best strategy for preserving feature diversity in the Cape. We should be able to use PD to identify those key regions that maximize future options, both for the continuing evolution of life on Earth and for the benefit of society.

Complementarity and the use of indicator groups for reserve selection in Uganda

A major obstacle to conserving tropical biodiversity is the lack of information as to where efforts should be concentrated. One potential solution is to focus on readily assessed indicator groups, whose distribution predicts the overall importance of the biodiversity of candidate areas,. Here we test this idea, using the most extensive data set on patterns of diversity assembled so far for any part of the tropics. As in studies of temperate regions, we found little spatial congruence in the species richness of woody plants, large moths, butterflies, birds and small mammals across 50 Ugandan forests. Despite this lack of congruence, sets of priority forests selected using data on single taxa only often captured species richness in other groups with the same efficiency as using information on all taxa at once. This is because efficient conservation networks incorporate not only species-rich sites, but also those whose biotas best complement those of other areas. In Uganda, different taxa exhibit similar biogeography, so priority forests for one taxon collectively represent the important forest types for other taxa as well. Our results highlight the need, when evaluating potential indicators for reserve selection, to consider cross-taxon congruence in complementarity as well as species richness.

ECOSYSTEM SERVICES AND ECONOMIC THEORY: INTEGRATION FOR POLICY‐RELEVANT RESEARCH

It has become essential in policy and decision-making circles to think about the economic benefits (in addition to moral and scientific motivations) humans derive from well-functioning ecosystems. The concept of ecosystem services has been developed to address this link between ecosystems and human welfare. Since policy decisions are often evaluated through cost-benefit assessments, an economic analysis can help make ecosystem service research operational. In this paper we provide some simple economic analyses to discuss key concepts involved in formalizing ecosystem service research. These include the distinction between services and benefits, understanding the importance of marginal ecosystem changes, formalizing the idea of a safe minimum standard for ecosystem service provision, and discussing how to capture the public benefits of ecosystem services. We discuss how the integration of economic concepts and ecosystem services can provide policy and decision makers with a fuller spectrum of information for making conservation-conversion trade-offs. We include the results from a survey of the literature and a questionnaire of researchers regarding how ecosystem service research can be integrated into the policy process. We feel this discussion of economic concepts will be a practical aid for ecosystem service research to become more immediately policy relevant.

Monitoring Matters: Examining the Potential of Locally-based Approaches

Monitoring of biodiversity and resource use by professional scientists is often costly and hard to sustain, especially in developing countries, where financial resources are limited. Moreover, such monitoring can be logistically and technically difficult and is often perceived to be irrelevant by resource managers and the local communities. Alternatives are emerging, carried out at a local scale and by individuals with little formal education. The methods adopted span a spectrum, from participatory monitoring where aims and objectives are defined by the community, to ranger-based monitoring in protected areas. What distinguishes these approaches is that local people or local government staff are directly involved in data collection and (in most instances) analysis. In this issue of Biodiversity and Conservation, 15 case studies examine whether these new approaches can address the limitations of professional monitoring in developing countries. The case studies evaluate ongoing locally-based monitoring schemes involving more than 1500 community members in 13 countries. The papers are based on a symposium held in Denmark in April 2004 (www. monitoringmatters.org). Here, we review how the case studies shed light on the following key issues concerning locally-based methods: cost, sustainability, their ability to detect true local or larger-scale trends, their links to management decisions and action, and the empowerment of local constituencies. Locally-based monitoring appears to be consistently cheap relative to the costs of management and of professional monitoring, even though the start-up costs can be high. Most local monitoring schemes are still young and thus their chances of being sustained over the longer term are not yet certain. However, we believe their chances of surviving are better than many professional schemes, particularly when they are institutionalised within existing management structures, and linked to the delivery of ecosystem goods or services to local communities. When properly designed, local schemes yield locally relevant results that can be as reliable as those derived from professional monitoring. Many management decisions emanate from local schemes. The decisions appear to be taken promptly, in response to immediate threats to the environment, and often lead to community-based actions to protect habitats, species or the local flow of ecosystem benefits; however, few local schemes have so far led to actions beyond the local scale. Locally-based monitoring schemes often reinforce existing community-based resource management systems and lead to change in the attitude of locals towards more environmentally sustainable resource management. Locally-derived data have considerable unexplored potential to elucidate global patterns of change in the status of populations and habitats, the services they provide, and the threats they face, but more effort is needed to develop effective modalities for feeding locally-derived data up to national and international levels.

Governance and the loss of biodiversity

Most of the worlds biodiversity occurs within developing countries that require donor support to build their conservation capacity. Unfortunately, some of these countries experience high levels of political corruption, which may limit the success of conservation projects by reducing effective funding levels and distorting priorities. We investigated whether changes in three well surveyed and widespread components of biodiversity were associated with national governance scores and other socio-economic measures. Here we show that governance scores were correlated with changes in total forest cover, but not with changes in natural forest cover. We found strong associations between governance scores and changes in the numbers of African elephants and black rhinoceroses, and these socio-economic factors explained observed patterns better than any others. Finally, we show that countries rich in species and identified as containing priority areas for conservation have lower governance scores than other nations. These results stress the need for conservationists to develop and implement policies that reduce the effects of political corruption and, in this regard, we question the universal applicability of an influential approach to conservation that seeks to ban international trade in endangered species.

Measuring the changing state of nature

Abstract Most attempts to quantify the impact of humanity on nature and bring it to public attention have centred around estimates of extinction rates. Suggestions that these figures have been exaggerated are, in our view, misplaced, but extinction rate estimates do face other problems – inevitable uncertainty, an arguably weak link to economic value, and insensitivity to short-term change. We therefore look here at other large-scale measures of the changing state of nature, focusing on recent analyses of trends in population size, numbers of populations and habitat extent. In spite of being limited by sampling inadequacies, these data provide a sensitive short-term complement to the long-term perspective gained from considering extinction rates that can be linked directly both to economic values and to public concerns. Although further work is needed on extinction rates, we conclude that significant new emphasis should be placed on instituting broader, more systematic monitoring of habitats and populations.

When does conservation genetics matter

Is this short review we explore the genetic threats facing declining populations, focusing in particular on empirical studies and the emerging questions they raise. At face value, the two primary threats are slow erosion of genetic variability by drift and short-term lowering of fitness owing to inbreeding depression, of which the latter appears the more potent force. However, the picture is not this simple. Populations that have passed through a severe bottleneck can show a markedly reduced ability to respond to change, particularly in the face of novel challenges. At the same time, several recent studies reveal subtle ways in which species are able to retain more useful genetic variability than they ‘should’, for example by enhanced reproductive success among the most outbred individuals in a population. Such findings call into question the validity of simple models based on random mating, and emphasize the need for more empirical data aimed at elucidating precisely what happens in natural populations.