Competition between seed-eating rodents and ants in desert ecosystems

Three kinds of evidence indicate that desert rodents and ants compete for seeds: (i) extensive overlaps in diet, (ii) reciprocal increases when one taxon is experimentally excluded, and (iii) complementay patterns of diversity and biomass in georadients of productivity. The effect on seed resources and annual plan geoseems to be similar whether rodents, ants, or both are foraging.     

Scale dependence in plant biodiversity

The relationship between the number of species and the area sampled is one of the oldest and best-documented patterns in community ecology. Several theoretical models and field data from a wide range of plant and animal taxa suggest that the slope, z, of a graph of the logarithm of species richness against the logarithm of area is roughly constant, with z approximately 0.25. We collected replicated and randomized plant data at 11 spatial scales from 0.01 to 10(8) square meters in Great Britain which show that the slope of the log-log plot is not constant, but varies systematically with spatial scale, and from habitat to habitat at the same spatial scale. Values of z were low (0.1 to 0.2) at small scales (<100 square meters), high (0.4 to 0.5) at intermediate scales (1 hectare to 10 square kilometers), and low again (0.1 to 0.2) for the largest scale transitions (e.g., East Berks to all of Berkshire). Instead of one process determining changes in species richness across a wide range of scales, different processes might determine plant biodiversity at different spatial scales.     

Interoperability of biodiversity databases: biodiversity information on every desktop

Data about biodiversity are either scattered in many databases or reside on paper or other media not amenable to interactive searching. The Global Biodiversity Information Facility (GBIF) is a framework for facilitating the digitization of biodiversity data and for making interoperable an as-yet-unknown number of biodiversity databases that are distributed around the globe. In concert with other existing efforts, GBIF will catalyze the completion of a Catalog of the Names of Known Organisms and will develop search engines to mine the vast quantities of biodiversity data. It will be an outstanding tool for scientists, natural resource managers, and policy-makers.     

Dissecting amazonian biodiversity

Biogeographical and biodiversity studies in Iowland Amazonian rain forests typically refer to observed or postulated distribution barriers such as past unfavorable climates, mountains, rivers, and river floodplains that divide the uniform tierra firme (noninundated) forest. Present-day ecological heterogeneity within tierra firme has hardly been discussed in this context, although edaphic differences are known to affect species distribution patterns in both inundated areas and tierra firme. Quantification of landscape heterogeneity in Peruvian Iowland Amazonia (500,000 kilometers squared), based on field studies and satellite image analysis, shows that Peruvian Amazonia is considerably more heterogeneous than previously reported. These observations have implications for the research, management, and conservation of Amazonian biodiversity.     

Prospects for biodiversity

Assuming no radical transformation in human behavior, we can expect important changes in biodiversity and ecosystem services by 2050. A considerable number of species extinctions will have taken place. Existing large blocks of tropical forest will be much reduced and fragmented, but temperate forests and some tropical forests will be stable or increasing in area, although the latter will be biotically impoverished. Marine ecosystems will be very different from today's, with few large marine predators, and freshwater biodiversity will be severely reduced almost everywhere. These changes will not, in themselves, threaten the survival of humans as a species.