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Metagenomics is a complex of research methodologies aimed at characterizing microbial communities and cataloging microbial diversity and distribution without isolating or culturing organisms. This approach will unavoidably engender new ways of thinking about microbial ecology that supplant the concept of “species.” This concept—thanks to comparative genomics—has in any case become increasingly unsustainable, either as a way of binning diversity or as a biological reality. Communities will become the units of evolutionary and ecological study. Although metagenomic methods will increasingly find uses in protistology and mycology, the emphasis so far has been, and our focus here will be, on prokaryotes (bacteria and archaea).
We present a conceptual model for the ecology of the spring snowmelt recession based on the natural flow regime that relates the quantifiable components of magnitude, timing, and rate of change to abiotic and biotic factors that govern riverine processes. We find that shifts in the magnitude of the recession largely affect abiotic channel conditions, whereas shifts in the timing of the snowmelt primarily affect biotic conditions. Shifts in the rate of change affect both abiotic and biotic conditions, creating the largest observed changes to the stream ecosystem. We discuss these components with regard to the success of riverine species in California's Mediterranean-montane environment. We then present two scenarios of change to the spring snowmelt recession—effects of flow regulation and climate warming—and discuss their potential implications for riverine ecology. Our conceptual model can help guide watershed stakeholders toward a better understanding of the impacts of changing spring recession conditions on stream ecosystems.
The wetland complex is the functional ecological unit of the prairie pothole region (PPR) of central North America. Diverse complexes of wetlands contribute high spatial and temporal environmental heterogeneity, productivity, and biodiversity to these glaciated prairie landscapes. Climatewarming simulations using the new model WETLANDSCAPE (WLS) project major reductions in water volume, shortening of hydroperiods, and less-dynamic vegetation for prairie wetland complexes. The WLS model portrays the future PPR as a much less resilient ecosystem: The western PPR will be too dry and the eastern PPR will have too few functional wetlands and nesting habitat to support historic levels of waterfowl and other wetland-dependent species. Maintaining ecosystem goods and services at current levels in a warmer climate will be a major challenge for the conservation community.
Today, human behavior drives many extinctions and preserves some species. To help understand such behavior, we published a book in 1999 that viewed selected endangered species through the eyes of those who have watched them decline and, in some cases, vanish from the wild. Here we revisit those stories to document what has happened in the interim 10 years, a period that is very short in evolutionary time but that has proven decisive for some endangered species. One species is now extinct in the wild; others have been devastated or scattered; several are on “life support.” Some things have not changed: Too many people consume too much, and disagreements among conservationists still impede progress. Some issues have become more prominent, such as emerging diseases and global economic crises. Although there have been some striking successes, it is very clear that more species now depend on human support for their survival than may be sustainable.
The absence of top-level predators in many natural areas in North America has resulted in overabundant ungulate populations, cascading negative impacts on plant communities, and the loss of biodiversity and ecosystem processes. Meanwhile, distinct population segments of the gray wolf (Canis lupus) have been removed from the list of endangered and threatened species, implying an end to wolf recovery and reintroductions. We propose another paradigm for wolf conservation, one that emphasizes ecosystem recovery instead of wolf recovery. Improvements in technology, an enhanced understanding of the ecological role of wolves, lessons from other countries, and changing public attitudes provide a new context and opportunity for wolf conservation and ecosystem restoration. Under this new paradigm, small populations of wolves, even single packs, could be restored to relatively small natural areas for purposes of ecosystem restoration and stewardship. We acknowledge the complications and challenges involved in such an effort, but assert that the benefits could be substantial.