Suchergebnisse

In this report we evaluate adaptation issues for natural ecosystems. We will specifically focus on the interactions with the abiotic environment of plants and animals, along with other organisms with which they interact (e.g., disease-causing bacteria and viruses). We further limit ourselves to natural ecosystems in which the predominant vegetation has developed without having been planted, irrigated, or fertilized. Most of the natural lands in the United States are managed by federal or state governments. Agricultural lands— including range grazing lands — are dealt with in a related adaptation report. This will evaluate the potential magnitudes and challenges facing terrestrial ecosystems in the United States in adapting to changing climate over the next 30-50 years. Our report will not address attribution or mitigation of climate change, as these topics have been dealt with in many other forums. We will begin with a brief summary of the current trajectory of the changing climate in the United States, including both temporal and spatial patterns. We will then relate these trends to ecosystem impacts and vulnerabilities.

Monitoring of rare and declining species is one of the most important tasks of wildlife managers. Here we present a large-scale, long-term monitoring program for Olympic marmot (Marmota olympus) throughout its range across a logistically challenging mountainous park. Our multiple-stage process of survey design accounts for the difficulty imposed by access to remote habitats and funding constraints. The Olympic marmot is endemic to the Olympic Mountains, Washington State, USA. Although nearly all of its range is enclosed within Olympic National Park, declines and local extirpations of the species have been documented. We considered several possible alternative survey approaches, and propose a monitoring program designed to reflect extinction–recolonisation dynamics using presence–absence data. The sampling design is based on annual surveys of a set of at least 25 randomly selected clusters (closely located groups of sites with record of current or historical occupancy by marmots), and supplemented by sampling 15 never-occupied sites to test for new colonisations. The monitoring plan provides a framework that park managers can use for assessing changes over time in Olympic marmot distribution across the range of the species. Our sampling design may serve as a useful case study for establishing monitoring programs for other species with clumped distributions.

Defining units that can be afforded legal protection is a crucial, albeit challenging, step in conservation planning. As we illustrate with a case study of the red wolf (Canis rufus) from the southeastern United States, this step is especially complex when the evolutionary history of the focal taxon is uncertain. The US Endangered Species Act (ESA) allows listing of species, subspecies, or Distinct Population Segments (DPSs) of vertebrates. Red wolves were listed as an endangered species in 1973, and their status remains precarious. However, some recent genetic studies suggest that red wolves are part of a small wolf species (C. lycaon) specialized for heavily forested habitats of eastern North America, whereas other authors suggest that red wolves arose, perhaps within the last ~400 years, through hybridization between gray wolves (C. lupus) and coyotes (C. latrans). Using published genetic, morphological, behavioral, and ecological data, we evaluated whether each evolutionary hypothesis would lead to a listable unit for red wolves. Although the potential hybrid origin of red wolves, combined with abundant evidence for recent hybridization with coyotes, raises questions about status as a separate species or subspecies, we conclude that under any proposed evolutionary scenario red wolves meet both criteria to be considered a DPS: they are Discrete compared with other conspecific populations, and they are Significant to the taxon to which they belong. As population-level units can qualify for legal protection under endangered-species legislation in many countries throughout the world, this general approach could potentially be applied more broadly.