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Protected areas provide some of the last refuges for Asian elephants in the wild. Managing these areas for elephants will be critical for elephant conservation. Scientists know little about elephant habitat use in Asia and how invasive species or livestock grazing influence habitat use. We studied these issues in two protected areas in Sri Lanka, Udawalawe National Park and Hurulu Eco-Park. These areas contain some of Sri Lanka's largest remaining grasslands. These grasslands are threatened by the invasive and toxic shrub, Lantana camara, and are used for illegal livestock grazing. To measure habitat use by elephants and livestock, we conducted dung surveys along over 50 km of transects stratified across grassland, scrub, and forest. We surveyed 159 vegetation plots along these transects to assess plant composition, and mapped habitat types based on satellite images. We used mixed-effect models to determine the relative importance of habitats, livestock presence, and plant associations for elephant use. Elephant presence was greatest in scrub and grassland habitats, positively associated with both livestock presence and short graminoids, and unaffected by L. camara, which was widespread but at low densities. Given the importance of these areas to elephants, we recommend a precautionary management approach that focuses on curbing both illegal grazing and the spread of L. camara.

The Double-crested Cormorant (Phalacrocorax auritus) is culled in many states because of the real and presumed damages it inflicts on farmed and recreational fisheries and other ecosystem services. Resident cormorant colonies breeding in the southeastern United States are protected in some areas, so it is important to distinguish these from co-occurring but unprotected migratory cormorants. Migratory P. auritus are likely to contain helminthic parasite communities that differ from those of non-migratory, resident birds, because they will encounter a wider variety of habitats and intermediate host communities during migrations. Here, we document five distinct assemblages of helminth parasites collected from 218 P. auritus culled from 11 sites in Alabama, Minnesota, Mississippi, and Vermont. The assemblages of P. auritus parasites are distinct among many sampling locations and can be used to correctly predict where a host cormorant has been feeding. We provide evidence for mixing of cormorants at a regional scale using discriminant analysis, which suggests there is a single population of migratory cormorants. Furthermore, our models strongly differentiate between migratory and resident P. auritus in the southeastern United States. In conjunction with species-by species latitudinal and longitudinal trends, our models could serve as effective tools for managers interested in both the population control of migratory cormorants and the conservation of non-migratory, resident birds. Finally, parasite counts per host are notoriously variable with many zeros and a few large numbers, leading many researchers to use simple prevalence in their analyses. We show that an intermediate level of data resolution, using species occurrence ranks within individual hosts, behaves well statistically and provides the greatest discrimination among distinct host groupings.

The role of inbreeding depression in the extinction of wild populations is controversial, largely because there are no quantitative estimates of its impact using realistic levels of inbreeding depression. To address this deficiency, this study (1) provides a comprehensive estimate of the impact of inbreeding depression on wild, mammalian and avian species via a meta-analysis, and (2) determines the impact of this level of inbreeding depression on extinction risk over a broad taxonomic range via stochastic computer projections with and without inbreeding depression for populations with carrying capacities of 100, 500 and 2000 individuals. An average overall effect of 12 diploid lethal equivalents was found across the life-history of the species in the meta-analysis. In the stochastic computer projections, 12 diploid lethal equivalents of inbreeding depression (with purging) decreased median times to extinction by an average of 37%. These decreases were significant and of very similar magnitude, regardless of the carrying capacity modelled. Disregarding the influence of inbreeding depression on extinction risk will lead to serious overestimates of the survival prospects of threatened mammalian and avian taxa. Further, inappropriate recovery plans may be instituted if the causes of extinction risk and their relative contributions are not recognized.

All models of speciation involve some mechanism for the separation of biological populations that eventually leads to the formation of new species. In the case of aquatic species, biological evolution is often coincident with geological evolution, because populations can become geographically isolated among river systems as drainage morphologies evolve. Thus, for species that are completely restricted to aquatic habitats (e.g., Wshes), river drainages provide a powerful framework for reconstructing phylogeny and historical biogeography (Avise, 1994). The southern region of the Appalachian mountains is a model setting for investigating the historical diVerentiation of populations in aquatic environments. The region’s communities and topography are very old as they were well south of the maximum extent of Pleistocene glaciation. The result has been the persistence of biota in the region and the opportunity for diversiWcation with time. For example, the Tennessee River system, which drains the western slopes and interior of the southern Appalachians, has the highest species richness and greatest number of endemic species of Wshes in North America (Jenkins et al., 1972; Starnes and Etnier

In most population models, the per-capita growth rate is assumed to decline monotonically with density. Here, I consider a model of one or more species in which the per-capita growth rate increases with population size at low densities. These populations will interact as intra- and interspecific mutualists if natural enemies can stabilize them at low levels. This idea is tested with examples of phytophagous insects that have humped per-capita growth curves because of plant physiological responses to herbivory. As predicted, these insects exploit this effect with a wide array of subsocial behaviors, parthenogenesis, and even the evolution toward gregarious, sessile living. This model differs from others in the literature in two ways: the mutualism only occurs at low densities and therefore requires the action of natural enemies; and the benefit may be conferred to individuals of the same as well as of other species.

Oxidized kaurene derivatives were isolated from the leaves of Solidago missouriensis and S. rigida and identified as kauran-16β-ol, kaur-16-en-19-oic acid and 7β-hydroxykaur-16-en-19-oic acid. The structure of the latter compound was determined by X-ray crystallographic analysis of its methyl ester.