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At an industrial park in Walnut Creek, California, technicians and robots are sorting through the 550 million base pairs of genetic code in poplar DNA to sequence a tree genome for the first time. They are poised to unlock a fine, full toolbox for the work of genetic engineering in trees.
Many hypotheses have been proposed to explain the decline of coral reefs throughout the world, but none adequately accounts for the lack of recovery of reefs or the wide geographical distribution of coral diseases. The processes driving the decline remain elusive. Hundreds of millions of tons of dust transported annually from Africa and Asia to the Americas may be adversely affecting coral reefs and other downwind ecosystems. Viable microorganisms, macro- and micronutrients, trace metals, and an array of organic contaminants carried in the dust air masses and deposited in the oceans and on land may play important roles in the complex changes occurring on coral reefs worldwide.
The introduction of new predators and pathogens has caused numerous well-documented extinctions of long-term resident species, particularly in spatially restricted environments such as islands and lakes. However, there are surprisingly few instances in which extinctions of resident species can be attributed to competition from new species. This suggests either that competition-driven extinctions take longer to occur than those caused by predation or that biological invasions are much more likely to threaten species through intertrophic than through intratrophic interactions. The likely threat of introduced species to resident controphics (species in the same trophic level) can be assessed with the help of existing biodiversity and extinction data sets and of two recent theories: (1) the fluctuating resource availability hypothesis, developed to account for changes in the invasibility of communities, and (2) the unified neutral theory, proposed to account for patterns of biodiversity at the community and metacommunity levels. Taken together, theory and data suggest that, compared to intertrophic interactions and habitat loss, competition from introduced species is not likely to be a common cause of extinctions of long-term resident species at global, metacommunity, and even most community levels.
Large-scale, landscape-level restoration actions are widely implemented but receive little attention from academic ecologists. We review the methods used to assess the role of these processes in past studies, and suggest ways to use past and ongoing restoration activities to increase our understanding of large-scale processes and improve restoration projects. To make better use of past restoration, we recommend the use of a number of alternative analytical approaches that have become widely applied in conservation biology and wildlife management but have yet to be adopted in restoration ecology.
Many insect species engage in high-altitude, wind-borne migration, often several hundred meters above the ground. At these heights they can use the wind to travel tens or hundreds of kilometers in a single flight, and hence a knowledge of their movements is essential to understanding their ecology and population dynamics. Direct observation of high-flying insect migrants is very difficult, especially at night, but the remote sensing capabilities of entomological radar provide a solution to this seemingly intractable problem. We describe a novel, nutating-beam, vertical-looking radar with autonomous data analysis software. This system routinely extracts data on size, shape, alignment, and displacement vectors from individual targets, allowing long-term monitoring of migrant insect populations. We discuss the capabilities and limitations of this system and describe some of its applications in the study of insect migration behaviour.
The environmental risks of many transgenic crops can be evaluated without additional experimentation by using already available information on the biology of the crop, the presence of compatible relatives, and the transgene phenotype. The level of crop invasiveness and the location of compatible relatives can be determined by consulting local floras and the crop literature. Decisions about invasiveness can be bolstered by determining the number of weediness traits carried by the crop and its congeners. The potential impact of transgenes can be ranked by their likely effect on reproductive success, ranging from neutral to advantageous to detrimental. This scheme can identify not only the low-risk transgene–crop combinations that are safe to deploy but also those that either are too dangerous to release or require additional experimentation.