As the terrestrial human footprint continues to expand, the amount of native forest that is free from significant damaging human activities is in precipitous decline. There is emerging evidence that ...the remaining intact forest supports an exceptional confluence of globally significant environmental values relative to degraded forests, including imperilled biodiversity, carbon sequestration and storage, water provision, indigenous culture and the maintenance of human health. Here we argue that maintaining and, where possible, restoring the integrity of dwindling intact forests is an urgent priority for current global efforts to halt the ongoing biodiversity crisis, slow rapid climate change and achieve sustainability goals. Retaining the integrity of intact forest ecosystems should be a central component of proactive global and national environmental strategies, alongside current efforts aimed at halting deforestation and promoting reforestation.
Most ecological hypotheses about species coexistence hinge on species differences, but quantifying trait differences across species in diverse communities is often unfeasible. We examined the ...variation of demographic traits using a global tropical forest data set covering 4500 species in 10 large-scale tree inventories. With a hierarchical Bayesian approach, we quantified the distribution of mortality and growth rates of all tree species at each site. This allowed us to test the prediction that demographic differences facilitate species richness, as suggested by the theory that a tradeoff between high growth and high survival allows species to coexist. Contrary to the prediction, the most diverse forests had the least demographic variation. Although demographic differences may foster coexistence, they do not explain any of the 16-fold variation in tree species richness observed across the tropics.
In Amazonian tropical forests, recent studies have reported increases in aboveground biomass and in primary productivity, as well as shifts in plant species composition favouring fast-growing species ...over slow-growing ones. This pervasive alteration of mature tropical forests was attributed to global environmental change, such as an increase in atmospheric CO2 concentration, nutrient deposition, temperature, drought frequency, and/or irradiance. We used standardized, repeated measurements of over 2 million trees in ten large (16-52 ha each) forest plots on three continents to evaluate the generality of these findings across tropical forests. Aboveground biomass increased at seven of our ten plots, significantly so at four plots, and showed a large decrease at a single plot. Carbon accumulation pooled across sites was significant (+0.24 MgC ha(-1) y(-1), 95% confidence intervals 0.07, 0.39 MgC ha(-1) y(-1)), but lower than reported previously for Amazonia. At three sites for which we had data for multiple census intervals, we found no concerted increase in biomass gain, in conflict with the increased productivity hypothesis. Over all ten plots, the fastest-growing quartile of species gained biomass (+0.33 0.09, 0.55 % y(-1)) compared with the tree community as a whole (+0.15 % y(-1)); however, this significant trend was due to a single plot. Biomass of slow-growing species increased significantly when calculated over all plots (+0.21 0.02, 0.37 % y(-1)), and in half of our plots when calculated individually. Our results do not support the hypothesis that fast-growing species are consistently increasing in dominance in tropical tree communities. Instead, they suggest that our plots may be simultaneously recovering from past disturbances and affected by changes in resource availability. More long-term studies are necessary to clarify the contribution of global change to the functioning of tropical forests.
In 1992, with the United Nations Conference on Environment and Development in Rio de Janeiro and the subsequent Convention on Biological Diversity (CBD), the world changed for the science of ...taxonomy. Many taxonomists appear not to have noticed this change, but it has significantly altered the political climate in which taxonomic research is undertaken. By the late 1990s it was clear that effective implementation of the CBD needed the participation of and funding for the taxonomic community. In this paper, I chart the rise of the Global Taxonomy Initiative (GTI), review some of its goals and explore how it interacts with the CBD. The interactions of the GTI with the Global Environment Facility, a potential funding body, are explored, as are the possible synergies between the GTI and the many other global initiatives linking to taxonomy. Finally, I explore some of the challenges ahead as taxonomy begins to take a front seat in the implementation of environmental policy on the world stage.
Can We Defy Nature's End? Pimm, Stuart L.; Ayres, Márcio; Balmford, Andrew ...
Science (American Association for the Advancement of Science),
09/2001, Volume:
293, Issue:
5538
Journal Article
Peer reviewed
Pimm et al raise questions regarding the enforceability of measures to protect natural ecosystems and prevent extinctions. Across several human generations, a transition to sustainable use of natural ...resources is essential, and biodiversity must be protected in the interim.
Crisis for Biodiversity Collections Miller, Scott E.; Kress, W. John; Cristián Samper K.
Science (American Association for the Advancement of Science),
01/2004, Volume:
303, Issue:
5656
Journal Article
Samper discusses science and environmental policy for sustainable development. There have been a number of attempts to strengthen the scientific basis of environmental policies, including a wide ...range of assessments of current environmental knowledge and its relevance for decision-making. Perhaps the best known is the Intergovernmental Panel on Climate Change, which has produces three reports through a process that involves hundreds of scientists worldwide.
PDF
