Richard D. Gregory

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.

Essential Biodiversity Variables

A global system of harmonized observations is needed to inform scientists and policy-makers. Reducing the rate of biodiversity loss and averting dangerous biodiversity change are international goals, reasserted by the Aichi Targets for 2020 by Parties to the United Nations (UN) Convention on Biological Diversity (CBD) after failure to meet the 2010 target (1, 2). However, there is no global, harmonized observation system for delivering regular, timely data on biodiversity change (3). With the first plenary meeting of the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) soon under way, partners from the Group on Earth Observations Biodiversity Observation Network (GEO BON) (4) are developing—and seeking consensus around—Essential Biodiversity Variables (EBVs) that could form the basis of monitoring programs worldwide.

A mid-term analysis of progress toward international biodiversity targets

In 2010, the international community, under the auspices of the Convention on Biological Diversity, agreed on 20 biodiversity-related “Aichi Targets” to be achieved within a decade. We provide a comprehensive mid-term assessment of progress toward these global targets using 55 indicator data sets. We projected indicator trends to 2020 using an adaptive statistical framework that incorporated the specific properties of individual time series. On current trajectories, results suggest that despite accelerating policy and management responses to the biodiversity crisis, the impacts of these efforts are unlikely to be reflected in improved trends in the state of biodiversity by 2020. We highlight areas of societal endeavor requiring additional efforts to achieve the Aichi Targets, and provide a baseline against which to assess future progress. Although conservation efforts are accelerating, their impact is unlikely to improve the global state of biodiversity by 2020. Indicators of progress and decline The targets set by the Convention on Biological Diversity in 2010 focused international efforts to alleviate global biodiversity decline. However, many of the consequences of these efforts will not be evident by the 2020 deadline agreed to by governments of 150 countries. Tittensor et al. analyzed data on 55 different biodiversity indicators to predict progress toward the 2020 targets—indicators such as protected area coverage, land-use trends, and endangered species status. The analysis pinpoints the problems and areas that will need the most attention in the next few years. Science, this issue p. 241

EU agricultural reform fails on biodiversity

Extra steps by Member States are needed to protect farmed and grassland ecosystems In December 2013, the European Union (EU) enacted the reformed Common Agricultural Policy (CAP) for 2014–2020, allocating almost 40% of the EUs budget and influencing management of half of its terrestrial area. Many EU politicians are announcing the new CAP as “greener,” but the new environmental prescriptions are so diluted that they are unlikely to benefit biodiversity. Individual Member States (MSs), however, can still use flexibility granted by the new CAP to design national plans to protect farmland habitats and species and to ensure long-term provision of ecosystem services.

An indicator of the impact of climatic change on European bird populations.

Rapid climatic change poses a threat to global biodiversity. There is extensive evidence that recent climatic change has affected animal and plant populations, but no indicators exist that summarise impacts over many species and large areas. We use data on long-term population trends of European birds to develop such an indicator. We find a significant relationship between interspecific variation in population trend and the change in potential range extent between the late 20th and late 21st centuries, forecasted by climatic envelope models. Our indicator measures divergence in population trend between bird species predicted by climatic envelope models to be favourably affected by climatic change and those adversely affected. The indicator shows a rapid increase in the past twenty years, coinciding with a period of rapid warming.

Sampling Effort and Parasite Species Richness

Comparative studies of parasite species richness among host taxa can be confounded by uneven sampling effort. Sampling ceases to be a confounding factor when extrapolation methods are used to estimate true species richness. Here, Bruno Walther and colleagues review examples of sampling bias and the use of extrapolation methods for circumventing it. They also discuss the confounding effects of phylogenetic association of estimates of species richness.

Wild bird indicators: using composite population trends of birds as measures of environmental health

Abstract World leaders have set global and regional targets to reduce the rate of biodiversity loss by 2010, and their relative success, or failure, in meeting these aims will be measured against a set of indicators. For such indicators to be effective, they need to meet a range of practical and scientific criteria. Their development is often driven pragmatically by the information available, One such biodiversity indicator that has proven highly effective and influential in Europe is the wild bird indicator. This is based on the composite population trends of birds combined using a geometric mean and derived from national breeding bird surveys, Recent work has emphasized the importance of common species to ecosystem functioning and suggested that the depletion of their populations might significantly affect ecosystem services. National governments and the European Union are increasingly using these measures to assess sustainable development strategies, environmental and ecosystem health, as well as in the fulfillment of biodiversity targets, Equivalent indicators have been published in North America. There are a number of reasons to believe that birds might be useful indicators of biodiversity. They are sensitive to anthropogenic changes, they are well known, excellent time-series exist, and they have a resonance and connection with people and their lives. Yet, there are counter arguments and some risks in using birds in this way. Our work provides a blueprint for others to follow using similar data on birds or other taxa, and in other countries and regions. In the discussion, we review the strengths and weaknesses of using bird population trends as biodiversity indicators, and look forward to how this work might be developed. Wild bird indicators only measure a component of biodiversity change and need to be used carefully to assist policy makers and land managers in managing the natural resources and conserving nature.

Survival rates of tropical and temperate passerines : a Trinidadian perspective

Mark‐recapture data collected using mist nets over a 10‐yr period in Trinidad were used to estimate adult survival rates for 17 species of forest passerines. Trinidadian survival rates (mean 65%, range 45%—85%) were significantly higher than published estimates for European (mean survival 52%, range 32%–71%) and North American (mean survival 53%, range 29%–63%) passerines of similar body size (equivalent to 45% higher mean life expectancy in Trinidad). These findings were confirmed after controlling for phylogeny using a method of independent contrasts. Transient and/or young birds were an important feature of the Trinidad data, and studies that fail to allow for the presence of such birds risk underestimating adult survival. This study lends support to the hypothesis that avian survival rates are higher in the humid tropics, although the magnitude of the difference may be smaller than previously suggested.

Common European birds are declining rapidly while less abundant species' numbers are rising

Biodiversity is undergoing unprecedented global decline. Efforts to slow this rate have focused foremost on rarer species, which are at most risk of extinction. Less interest has been paid to more common species, despite their greater importance in terms of ecosystem function and service provision. How rates of decline are partitioned between common and less abundant species remains unclear. Using a 30-year data set of 144 bird species, we examined Europe-wide trends in avian abundance and biomass. Overall, avian abundance and biomass are both declining with most of this decline being attributed to more common species, while less abundant species showed an overall increase in both abundance and biomass. If overall avian declines are mainly due to reductions in a small number of common species, conservation efforts targeted at rarer species must be better matched with efforts to increase overall bird numbers, if ecological impacts of birds are to be maintained.

Robustness of reserve selection procedures under temporal species turnover

Complementarity‐based algorithms for the selection of reserve networks emphasize the need to represent biodiversity features efficiently, but this may not be sufficient to maintain those features in the long term. Here, we use data from the Common Birds Census in Britain as an exemplar data set to determine guidelines for the selection of reserve networks which are more robust to temporal turnover in features. The extinction patterns found over the 1981–1991 interval suggest that two such guidelines are to represent species in the best sites where they occur (higher local abundance) and to give priority to the rarer species. We tested five reserve selection strategies, one which finds the minimum representation set and others which incorporate the first or both guidelines proposed. Strategies were tested in terms of their efficiency (inversely related to the total area selected) and effectiveness (inversely related to the percentage of species lost) using data on eight pairs of ten‐year intervals. The minimum set strategy was always the most efficient, but suffered higher species loss than the others, suggesting that there is a trade‐off between efficiency and effectiveness. A desirable compromise can be achieved by embedding the concerns about the long‐term maintenance of the biodiversity features of interest in the complementarity‐based algorithms.