Since the early 1970s there has been increasing interest in the ecological effects of bottom‐fishing activities on the benthic ecology of the seas of northern Europe. The majority of studies have examined the short‐term effects of disturbance on benthic fauna. Some areas, however, such as the southern North Sea, have been subjected to fishing disturbance for over 50 years, which complicates predictions of long‐term ecological...

We investigated the distribution of alkaloid‐rich plant species in shortgrass steppe vegetation. The intent was to identify and to determine if alkaloid‐rich species were more prevalent in certain habitats or life forms and to determine if ethnomedicinal accounts were an indicator of alkaloid‐rich taxa. Alkaloid screening tests were performed on plant tissues from 77% of 275 plant species that occurred at the Central Plains Ex...

Adequate population viability assessment may require estimation of effective population size ( N e ). But failure to take into account the effect of temporal fluctuation in population size (FPS) on N e may routinely lead to unrealistically optimistic viability assessments. We thus evaluate a technique that accounts for the effect of FPS on N e . Using time series of annual counts of 48 free‐ranging animal populations, we show...

The World Conservation Union (IUCN) Red List criteria endorsed in 1994 consist of a set of decision rules based on quantitative thresholds of population size, distributional range, rates of decline, and extinction risk. I evaluated these criteria using data on 68 vascular plant taxa from southeastern Australia and found that deficiencies could be overcome with modifications that did not substantially alter the structure of the...

Decimation of the California (U.S.A.) prairie has increased interest in the conservation and ecological restoration of grasslands composed of native perennial species. Widespread plantings are being attempted, and the potential for contaminating existing remnant populations with maladapted germplasm has led to concerns about the use of nonlocal seed sources. We evaluated regional patterns of isozyme and quantitative trait vari...

Social construction is the virtue ascribed to a subject by the general public; along with political power, it influences the allocation of public policy benefits. Nonhuman species are socially constructed by humans, and political power is held in trust for them by human interest groups. Our goal was to determine if the allocation of benefits to endangered species is consistent with social construction and political power. We a...

Most current methods available for assessing the conservation status of a species do not take into account the underlying uncertainty inherent in the data. A point estimate approach is generally adopted to interpret the data used in these assessments. For species that are not well known, the paucity of quality data produces an unreliable estimate of the species’ status. The assessment of threat, based upon a range of values re...

The Hastings River mouse ( Pseudomys oralis ) is a small, endangered Australian conilurine rodent. Only about 200 specimens of this rodent have ever been caught, and little is known about its biology. At present, populations of this species appear to be severely fragmented. We used temperature‐gradient gel electrophoresis and DNA sequencing to investigate maternal population structuring in this species and to determine if the...

From 1987 to 1996 we used capture and telemetry methods to study the demography, movements, and population trend of grizzly bears ( Ursus arctos horribilis ) in wilderness and nonwilderness portions of the Swan Mountains of Montana. Most data were collected in the nonwilderness portion, which included public multiple‐use lands and rural areas on and near private lands. Population density in nonwilderness averaged 1.6 bears/100...

Many semi‐aquatic organisms, such as salamanders, depend on both aquatic and terrestrial habitats to complete their life cycle and maintain viable populations. But current U.S. federal and state regulations protect only the wetland itself or arbitrarily defined portions of terrestrial habitat, if any. Part of the reason terrestrial habitats adjacent to wetlands are not protected is the lack of a clear understanding of the dist...

In managing rare species for conservation, we often need to make decisions based on existing, scanty data sets. Our ability to use such data effectively may be critical to our success in managing individual populations. We used viability analysis to examine the population dynamics of a threatened plant species, Rorippa columbiae , on Pierce Island in Washington (U.S.A.). Although the island was protected in part because of the...

We investigated the relationships among a number of population and site characteristics and the ovule and seed production and seed set in 17 populations of the rare, self‐compatible, bumblebee‐pollinated perennial Gentiana pneumonanthe L. in the Netherlands. Population size and offspring heterozygosity were used as population properties; grass and heath cover, soil concentrations of various ions, soil acidity (pH), and soil mo...