Biodiversity loss continues unabated despite international efforts

Note an extended version of this article was originally published on the Huffington Post here.  Also read about the study here on Futurity and here on the BBC.

Betting on biodiversity loss is a pretty sure thing.  The earth’s plant and animal species are disappearing at a sobering rate due to pressures including habitat loss, climate change, pollution and over-harvesting.  Despite a few success stories and steps in the right direction, we are falling far short of stemming these losses.

Biodiversity is the entire range of biological variety in the world, including the diversity of genotypes, species and ecosystems.  It can be measured on levels from DNA molecules all the way up to broad taxonomic categories such as families and phyla.  Monitoring the fate of any of these aspects of biodiversity at a global scale is a daunting task.  Thus, we know little about the rates and patterns of biodiversity loss or the effectiveness of global mitigation plans such as the 2002 Convention on Biological Diversity.

Dr. Stuart Butchart of the UNEP World Conservation Monitoring Centre and BirdLife International tackled the problem by assembling an international team of conservation scientists (that I was part of) to calculate trends in global biodiversity.  The idea was to assemble several dozen indices that we had sound, long term data for including population trends for birds and other vertebrates and the loss of habitats such as forests, seagrass beds and coral reefs.

As we recently reported in Science magazine (Butchart et al 2010), our analysis indicates that biodiversity has continued to decline over the past four decades with no detectable abatement for most indices.  This is largely due to increased pressures resulting from human population growth, economic development and globalization but it also seems clear that our international response to the biodiversity crisis has been inadequate.

Aggregated indices of (A) the state of biodiversity based on 9 indicators of species’ population trends, habitat extent/condition and community composition; (B) pressures on biodiversity based on 5 indicators of Ecological Footprint, nitrogen deposition, numbers of alien species, over-exploitation, and climatic impacts; and (C) responses for biodiversity based on 6 indicators of protected area extent and biodiversity coverage, policy responses to invasive alien species, sustainable forest management and biodiversity-related aid. Values in 1970 set to 1. Shading shows 95% confidence intervals derived from 1,000 bootstraps. Significant positive/upward (○) and negative/downward (●) inflections are indicated.

“Although nations have put in place some significant policies to slow biodiversity declines, these have been woefully inadequate, and the gap between the pressures on biodiversity and the responses is getting ever wider” – lead author Dr Stuart Butchart.

“Since 1970, we have reduced animal populations by 30%, the area of mangroves and sea grasses by 20% and the coverage of living corals by 40%”, said the United Nations Environment Programme’s Chief Scientist Prof Joseph Alcamo. “These losses are clearly unsustainable”

“While many responses have been in the right direction, the relevant policies have been inadequately targeted, implemented and funded. Above all, biodiversity concerns must be integrated across all parts of government and business, and the economic value of biodiversity needs to be accounted for adequately in decision making. Only then will we be able to address the problem,” says Ahmed Djoghlaf, Executive Secretary to the Convention on Biological Diversity.

Reference: Butchart, S. H. M., M. Walpole, B. Collen, A. van Strien, J. P. W. Scharlemann, R. E. A. Almond, J. E. M. Baillie, B. Bomhard, C. Brown, J. Bruno, K. E. Carpenter, G. M. Carr, J. Chanson, A. M. Chenery, J. Csirke, N. C. Davidson, F. Dentener, M. Foster, A. Galli, J. N. Galloway, P. Genovesi, R. D. Gregory, M. Hockings, V. Kapos, J.-F. Lamarque, F. Leverington, J. Loh, M. A. McGeoch, L. McRae, A. Minasyan, M. H. Morcillo, T. E. E. Oldfield, D. Pauly, S. Quader, C. Revenga, J. R. Sauer, B. Skolnik, D. Spear, D. Stanwell-Smith, S. N. Stuart, A. Symes, M. Tierney, T. D. Tyrrell, J.-C. Vie, and R. Watson. 2010. Global Biodiversity: Indicators of Recent Declines. Science: 1187512

Indicator trends for (A) the state of biodiversity, (B) pressures upon it, (C) responses to address its loss, and (D) the benefits humans derive from it. Data scaled to 1 in 1970 (or for first year of data if >1970), modeled (if >13 data points; see Table 1) and plotted on a logarithmic ordinate axis. Shading shows 95% confidence intervals except where unavailable.

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