Valerie Kapos

Global Biodiversity: Indicators of Recent Declines

Global Biodiversity Target Missed In 2002, the Convention on Biological Diversity (CBD) committed to a significant reduction in the rate of biodiversity loss by 2010. There has been widespread conjecture that this target has not been met. Butchart et al. (p. 1164, published online 29 April) analyzed over 30 indicators developed within the CBDs framework. These indicators include the condition or state of biodiversity (e.g., species numbers, population sizes), the pressures on biodiversity (e.g., deforestation), and the responses to maintain biodiversity (e.g., protected areas) and were assessed between about 1970 and 2005. Taken together, the results confirm that we have indeed failed to meet the 2010 targets. An analysis of 30 indicators shows that the Convention on Biological Diversity’s 2010 targets have not been met. In 2002, world leaders committed, through the Convention on Biological Diversity, to achieve a significant reduction in the rate of biodiversity loss by 2010. We compiled 31 indicators to report on progress toward this target. Most indicators of the state of biodiversity (covering species’ population trends, extinction risk, habitat extent and condition, and community composition) showed declines, with no significant recent reductions in rate, whereas indicators of pressures on biodiversity (including resource consumption, invasive alien species, nitrogen pollution, overexploitation, and climate change impacts) showed increases. Despite some local successes and increasing responses (including extent and biodiversity coverage of protected areas, sustainable forest management, policy responses to invasive alien species, and biodiversity-related aid), the rate of biodiversity loss does not appear to be slowing.

Tracking the ecological overshoot of the human economy

Sustainability requires living within the regenerative capacity of the biosphere. In an attempt to measure the extent to which humanity satisfies this requirement, we use existing data to translate human demand on the environment into the area required for the production of food and other goods, together with the absorption of wastes. Our accounts indicate that human demand may well have exceeded the biospheres regenerative capacity since the 1980s. According to this preliminary and exploratory assessment, humanitys load corresponded to 70% of the capacity of the global biosphere in 1961, and grew to 120% in 1999.

Classification of multispectral images based on fractions of endmembers: Application to land-cover change in the Brazilian Amazon

Abstract Four time-sequential Landsat Thematic Mapper (TM) images of an area of Amazon forest, pasture, and second growth near Manaus, Brazil were classified according to dominant ground cover, using a new technique based on fractions of spectral endmembers. A simple four-endmember model consisting of reflectance spectra of green vegetation, nonphotosynthetic vegetation, soil, and shade was applied to all four images. Fractions of endmembers were used to define seven categories, each of which consisted of one or more classes of ground cover, where class names were based on field observations. Endmember fractions varied over time for many pixels, reflecting processes operating on the ground such as felling of forest, or regrowth of vegetation in previously cleared areas. Changes in classes over time were used to establish superclasses which grouped pixels having common histories. Sources of classification error were evaluated, including system noise, endmember variability, and low spectral contrast. Field work during each of the four years showed consistently high accuracy in per-image classification. Classification accuracy in any one year was improved by considering the multiyear context. Although the method was tested in the Amazon basin, the results suggest that endmember classification may be generally useful for comparing multispectral images in space and time.

Biodiversity Conservation: Challenges Beyond 2010

Biodiversity Convention In October 2010, the Convention on Biological Diversity will meet to assess the current condition of global biodiversity and to propose and agree on priorities for its future conservation. In this context, Rands et al. (p. 1298; see the News Focus section; see the cover) review recent patterns of biodiversity conservation, highlighting successes, as well as current and future threats. They argue that biodiversity should be treated as a public good, with responsibility for its conservation integrated across sectors of society and government, rather than be confined to the business of environmental agencies, and review the conditions under which this goal might be achieved. The continued growth of human populations and of per capita consumption have resulted in unsustainable exploitation of Earth’s biological diversity, exacerbated by climate change, ocean acidification, and other anthropogenic environmental impacts. We argue that effective conservation of biodiversity is essential for human survival and the maintenance of ecosystem processes. Despite some conservation successes (especially at local scales) and increasing public and government interest in living sustainably, biodiversity continues to decline. Moving beyond 2010, successful conservation approaches need to be reinforced and adequately financed. In addition, however, more radical changes are required that recognize biodiversity as a global public good, that integrate biodiversity conservation into policies and decision frameworks for resource production and consumption, and that focus on wider institutional and societal changes to enable more effective implementation of policy.

Reducing Greenhouse Gas Emissions from Deforestation and Forest Degradation: Global Land-Use Implications

Recent climate talks in Bali have made progress toward action on deforestation and forest degradation in developing countries, within the anticipated post-Kyoto emissions reduction agreements. As a result of such action, many forests will be better protected, but some land-use change will be displaced to other locations. The demonstration phase launched at Bali offers an opportunity to examine potential outcomes for biodiversity and ecosystem services. Research will be needed into selection of priority areas for reducing emissions from deforestation and forest degradation to deliver multiple benefits, on-the-ground methods to best ensure these benefits, and minimization of displaced land-use change into nontarget countries and ecosystems, including through revised conservation investments.

The Living Planet Index: using species population time series to track trends in biodiversity

The Living Planet Index was developed to measure the changing state of the worlds biodiversity over time. It uses time-series data to calculate average rates of change in a large number of populations of terrestrial, freshwater and marine vertebrate species. The dataset contains about 3000 population time series for over 1100 species. Two methods of calculating the index are outlined: the chain method and a method based on linear modelling of log-transformed data. The dataset is analysed to compare the relative representation of biogeographic realms, ecoregional biomes, threat status and taxonomic groups among species contributing to the index. The two methods show very similar results: terrestrial species declined on average by 25% from 1970 to 2000. Birds and mammals are over-represented in comparison with other vertebrate classes, and temperate species are over-represented compared with tropical species, but there is little difference in representation between threatened and non-threatened species. Some of the problems arising from over-representation are reduced by the way in which the index is calculated. It may be possible to reduce this further by post-stratification and weighting, but new information would first need to be collected for data-poor classes, realms and biomes.

Global soil carbon: understanding and managing the largest terrestrial carbon pool

Carbon stored in soils worldwide exceeds the amount of carbon stored in phytomass and the atmosphere. Despite the large quantity of carbon stored as soil organic carbon (SOC), consensus is lacking on the size of global SOC stocks, their spatial distribution, and the carbon emissions from soils due to changes in land use and land cover. This article summarizes published estimates of global SOC stocks through time and provides an overview of the likely impacts of management options on SOC stocks. We then discuss the implications of existing knowledge of SOC stocks, their geographical distribution and the emissions due to management regimes on policy decisions, and the need for better soil carbon science to mitigate losses and enhance soil carbon stocks.

Hurricane effects on forest ecosystems in the Caribbean

Hurricanes are common, potentially catastrophic events for ecosystems in the Caribbean. We synthesize the work reported in this issue, together with the existing literature, to discuss effects of hurricanes on Caribbean ecosystems and to highlight priorities for future work. Comparisons of the impacts of hurricanes on different ecosystems are made difficult by the lack of detailed meteorological data, lack of prehurricane ecological data and differences between studies in types and timing of measurements made. Effects of recent hurricanes on Caribbean forest ecosystems include: defoliation, ranging from complete in lowland wet forest in Nicaragua after Hurricane Joan to negligible in parts of Jamaican montane forest after Hurricane Gilbert; felling of trees by uprooting and snapping (80% in Nicaragua to 14% in Jamaica); and tree mortality, which is rarely recorded and generally low (13% in the Yucatan following Hurricane Gilbert to 3% in Puerto Rican montane forests following Hurricane Hugo). Damage to individual trees varies with topographic location, stand characteristics, tree size (large ones uprooting and small ones snapping in Dominica during Hurricane David, but not in Jamaica), and species characteristics (such as wood density), but it is difficult to generalize about these factors. Effects on animal populations are both direct and through reductions in food supplies. Frugivorous and nectarivorous birds were more severely affected than insectivorous species in the Virgin Islands and Jamaica. There is little information about hurricane effects on insect populations, but populations of two species of walking sticks in Puerto Rico declined sharply after Hurricane Hugo. Numbers of adults of one frog species in Puerto Rico quadrupled after Hurricane Hugo, but numbers of juveniles were severely reduced by the storm. Effects of hurricanes on the physical environment include modified microclimates due to increased light penetration through defoliated canopies and landslides triggered by rainfall. Increased litterfall led to increases in some soil nutrients, and fine root biomass was drastically reduced in a Puerto Rican montane forest. Recovery of forest ecosystems from hurricanes depends on a combination of seedling growth and resprouting of canopy trees. In several studies, seed germination was promoted by higher light and/or higher temperature, but seedling mortality also increased. The relative importance of newly germinated seedlings, advance regeneration, and regrowth of damaged adults has not been studied. The few long-term studies of adult trees show the expected decline in the proportion of pioneer and intolerant species with time after disturbance. Hurricanes may be the most important factor controlling species composition and some aspects of ecosystem dynamics in the Caribbean; there is much still to be learned, and we suggest some priorities for future research.

A large-scale forest fragmentation experiment: the Stability of Altered Forest Ecosystems Project

Opportunities to conduct large-scale field experiments are rare, but provide a unique opportunity to reveal the complex processes that operate within natural ecosystems. Here, we review the design of existing, large-scale forest fragmentation experiments. Based on this review, we develop a design for the Stability of Altered Forest Ecosystems (SAFE) Project, a new forest fragmentation experiment to be located in the lowland tropical forests of Borneo (Sabah, Malaysia). The SAFE Project represents an advance on existing experiments in that it: (i) allows discrimination of the effects of landscape-level forest cover from patch-level processes; (ii) is designed to facilitate the unification of a wide range of data types on ecological patterns and processes that operate over a wide range of spatial scales; (iii) has greater replication than existing experiments; (iv) incorporates an experimental manipulation of riparian corridors; and (v) embeds the experimentally fragmented landscape within a wider gradient of land-use intensity than do existing projects. The SAFE Project represents an opportunity for ecologists across disciplines to participate in a large initiative designed to generate a broad understanding of the ecological impacts of tropical forest modification.

Floristics and biogeography of a rain forest in the Venezuelan Andes

The vascular flora of 1.5 ha of montane rain forest on a ridge top at 2550-2650 m near Merida, Venezuela was surveyed, compared with other montane forests in the region, and analysed to determine its biogeographic origins and affinities. The study included an inventory of all stems > 3.2 cm d.b.h. in eighteen 12 X 12 m plots. The canopy was 10-22 m tall and the trees relatively small (3488 individuals ha1, basal area 34.7 m2 ha1). Bamboos were abundant in gaps, there were no buttressed trees and relatively few climbers. Weinmannia glabra L.f. (Cunoniaceae), Clusia trochiformis Vesque (Guttiferae) and Hedyosmum crenatum Occhioni (Chloranthaceae) together accounted for 42% of the individuals and 37% of the basal area. Microphylls, notophylls and mesophylls predominated in the