Natural restoration of the species-area relation for a lizard after a hurricane.
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We document the decimation and recovery of the commonest lizard species, Anolis sagrei, on 66 islands in the Bahamas that were directly hit by Hurricane Floyd in September 1999. Before the hurricane, an island's area was a better predictor of the occurrence of A. sagrei than was its altitude. Immediately after, altitude was a better predictor: Apparently all lizards on islands lower than about 3 meters maximum elevation perished in the storm surge. After about 1 year, area again became the better predictor. By 19 months after the hurricane, A. sagrei populations occurred on 88% of the islands they formerly occupied. Recovery occurred via overwater colonization and propagation from eggs that survived inundation, mechanisms that were enhanced by larger island area. Thus, natural processes first destroyed and then quickly restored a highly regular species-area distribution. (+info)
Urban history, urban health.
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Over the course of the 20th century, the United States became an urban nation: 80% of Americans now live in metropolitan areas. Supplying basic sanitary services-drinking water, sewers, and garbage removal-to these cities is a gargantuan task, yet most people have little understanding of urban infrastructure systems and their enormous regional ecologic impacts. Municipalization of sanitary services, especially since 1880, distanced people from their wastes and gave city dwellers a simplistic experience of one-way material flow through cities, without knowledge of the environmental costs. Most sanitary infrastructures were built primarily for durability and lack the elasticity to meet changing needs. The challenge now is to adapt sanitary systems for flexibility and simultaneously move from unchecked material consumption toward resource-based thinking. (+info)
Effects of marine reserves on adjacent fisheries.
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Marine reserves have been widely promoted as conservation and fishery management tools. There are robust demonstrations of conservation benefits, but fishery benefits remain controversial. We show that marine reserves in Florida (United States) and St. Lucia have enhanced adjacent fisheries. Within 5 years of creation, a network of five small reserves in St. Lucia increased adjacent catches of artisanal fishers by between 46 and 90%, depending on the type of gear the fishers used. In Florida, reserve zones in the Merritt Island National Wildlife Refuge have supplied increasing numbers of world record-sized fish to adjacent recreational fisheries since the 1970s. Our study confirms theoretical predictions that marine reserves can play a key role in supporting fisheries. (+info)
Focus: who reaps the benefits of biodiversity?
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The search for wild plant and animal products of potential value to medicine, agriculture, and other uses has been going on for hundreds, possibly thousands, of years. Many commonly prescribed medicines in the United States include ingredients derived from natural products, and roughly 80% of the world's people rely on natural products for their primary medical needs. Until the past decade, all of these natural products were collected without compensating the source countries. But the rules of collecting changed in 1992 with the establishment of the Convention on Biological Diversity, which offers financial compensation for natural products and seeks to conserve biological diversity, use natural products sustainably, and fairly share products made from gene stocks. Questions remain, however, as to how to share the benefits of biodiversity equitably, as well as whether the lack of both U.S. support for the agreement and enforceability render the convention impotent. (+info)
Spatial patterns of morphological diversity across the Indo-Pacific: analyses using strombid gastropods.
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Biological diversity can be measured using various metrics, but existing knowledge of spatial patterns of diversity is largely based on species counts. There is increasing evidence that trends in species richness might not match trends in other biodiversity metrics, such as morphological diversity. Here, we use data from a large group of Indo-Pacific gastropods (family Strombidae) to show that the species richness of a region is a poor predictor of the morphological diversity present there. Areas with only a few species can harbour an impressive array of morphologies and, conversely, morphological diversity in the most species-rich regions is no higher than in regions with half their taxonomic diversity. Biological diversity in the Pacific is highly threatened by human activity and our results indicate that, in addition to species richness, morphological diversity metrics need to be incorporated into conservation decisions. (+info)
Unexpected coherence and conservation.
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The effects of migration in a network of patch populations, or metapopulation, are extremely important for predicting the possibility of extinctions both at a local and a global scale. Migration between patches synchronizes local populations and bestows upon them identical dynamics (coherent or synchronous oscillations), a feature that is understood to enhance the risk of global extinctions. This is one of the central theoretical arguments in the literature associated with conservation ecology. Here, rather than restricting ourselves to the study of coherent oscillations, we examine other types of synchronization phenomena that we consider to be equally important. Intermittent and out-of-phase synchronization are but two examples that force us to reinterpret some classical results of the metapopulation theory. In addition, we discuss how asynchronous processes (for example, random timing of dispersal) can paradoxically generate metapopulation synchronization, another non-intuitive result that cannot easily be explained by the standard theory. (+info)
Human appropriation of photosynthesis products.
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Previous global estimates of the human impact on terrestrial photosynthesis products depended heavily on extrapolation from plot-scale measurements. Here, we estimated this impact with the use of recent data, many of which were collected at global and continental scales. Monte Carlo techniques that incorporate known and estimated error in our parameters provided estimates of uncertainty. We estimate that humans appropriate 10 to 55% of terrestrial photosynthesis products. This broad range reflects uncertainty in key parameters and makes it difficult to ascertain whether we are approaching crisis levels in our use of the planet's resources. Improved estimates will require high-resolution global measures within agricultural lands and tropical forests. (+info)
Grassland management regimens reduce small-scale heterogeneity and species diversity of beta-proteobacterial ammonia pxidizer populations.
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The impact of soil management practices on ammonia oxidizer diversity and spatial heterogeneity was determined in improved (addition of N fertilizer), unimproved (no additions), and semi-improved (intermediate management) grassland pastures at the Sourhope Research Station in Scotland. Ammonia oxidizer diversity within each grassland soil was assessed by PCR amplification of microbial community DNA with both ammonia oxidizer-specific, 16S rRNA gene (rDNA) and functional, amoA, gene primers. PCR products were analysed by denaturing gradient gel electrophoresis, phylogenetic analysis of partial 16S rDNA and amoA sequences, and hybridization with ammonia oxidizer-specific oligonucleotide probes. Ammonia oxidizer populations in unimproved soils were more diverse than those in improved soils and were dominated by organisms representing Nitrosospira clusters 1 and 3 and Nitrosomonas cluster 7 (closely related phylogenetically to Nitrosomonas europaea). Improved soils were only dominated by Nitrosospira cluster 3 and Nitrosomonas cluster 7. These differences were also reflected in functional gene (amoA) diversity, with amoA gene sequences of both Nitrosomonas and Nitrosospira species detected. Replicate 0.5-g samples of unimproved soil demonstrated significant spatial heterogeneity in 16S rDNA-defined ammonia oxidizer clusters, which was reflected in heterogeneity in ammonium concentration and pH. Heterogeneity in soil characteristics and ammonia oxidizer diversity were lower in improved soils. The results therefore demonstrate significant effects of soil management on diversity and heterogeneity of ammonia oxidizer populations that are related to similar changes in relevant soil characteristics. (+info)