Genetic tracking of the brown bear in northern Pakistan and implications for conservation

Asian bears face major threats due to the impact of human activities as well as a critical lack of knowledge about their status, distribution and needs for survival. Once abundant in northern Pakistan, the Himalayan brown bear (Ursus arctos isabellinus) has been exterminated in most of its former distribution range. It presently occurs sparsely, in small populations, the Deosai National Park supporting the largest isolate. This decline might imply a reduction in genetic diversity, compromising the survival of the population. Using a combination of fecal DNA analysis and field data, our study aimed at assessing the size and genetic status of the Deosai population and give guidelines for its conservation and management. Using fecal genetic analysis, we estimated the population to be 40-50 bears, which compares well with the field census of 38 bears. The northern Pakistani brown bear population may have undergone an approximate 200-300-fold decrease during the last thousand years, probably due to glaciations and the influence of growing human population. However, in spite of the presence of a bottleneck genetic signature, the Deosai population has a moderate level of genetic diversity and is not at immediate risk of inbreeding depression. Gene flow might exist with adjacent populations. We recommend careful monitoring of this population in the future both with field observations and genetic analyses, including sampling of adjacent populations to assess incoming gene flow. The connectivity with adjacent populations in Pakistan and India will be of prime importance for the long-term survival of Deosai bears.     

Optimisation of larval culture of the mussel <Emphasis Type="Italic">Mytilus</Emphasis><Emphasis Type="Italic">edulis</Emphasis> (L.)

The blue mussel Mytilus edulis is a commercially important species whose fishery and culture generally relies on natural spat collection. Hatchery-production could provide an alternative source of seed, enabling reliable expansion of the industry. Mussel spawning and larval rearing trials were carried out to optimise elements of hatchery production. Culturing fertilised eggs at low density (20–200 eggs cm⁻²) rather than high density (400–720 eggs cm⁻²) significantly improved the quality of first veliger larvae and differences in this improvement were evident between the eggs from different females (maternal effects). Veliger larval growth at 17 or 21°C was significantly faster than growth at 14°C. Feeding veliger larvae an identical total ration either daily or at 2–3 day intervals did not significantly affect their growth. Different microalgal diets (1: Isochrysis sp. (clone T-ISO), 2: Chaetoceros calcitrans forma pumilus, 3: C. muelleri, 4: mixed Isochrysis sp. (clone T-ISO) and C. calcitrans f. pumilus, and 5: mixed Isochrysis sp. (clone T-ISO) and C. muelleri) were tested on veliger larval growth and mixed diets outperformed single-species diets.     

Rocky Mountain ecosystems: diversity, complexity and interactions

The interior west of North America provides many opportunities to study ecosystem responses to climate change, biological diversity and management of disturbance regimes. These ecosystem responses are not unique to the Rocky Mountains, but they epitomize similar scientific problems throughout North America. Better management of these ecosystems depends on a thorough understanding of the underlying biology and ecological interactions of the species that occupy the diverse habitats of this region. This review highlights progress in research to understand aspects of this complex ecosystem.     

Quantitative analysis of culture using millions of digitized books

We constructed a corpus of digitized texts containing about 4% of all books ever printed. Analysis of this corpus enables us to investigate cultural trends quantitatively. We survey the vast terrain of 'culturomics,' focusing on linguistic and cultural phenomena that were reflected in the English language between 1800 and 2000. We show how this approach can provide insights about fields as diverse as lexicography, the evolution of grammar, collective memory, the adoption of technology, the pursuit of fame, censorship, and historical epidemiology. Culturomics extends the boundaries of rigorous quantitative inquiry to a wide array of new phenomena spanning the social sciences and the humanities.     

Mechanical site preparation effects on understory plant diversity in the Piedmont of the southern USA

Diversity of understory vegetation was compared among four intensities of site preparation and an adjacent 50-year-old pine-hardwood forest. The study site was a six-year-old loblolly pine (Pines taeda) plantation in the lower Piedmont of Georgia. Species richness and Shannon diversity indices were used to evaluate vine and woody (trees and shrubs) species diversity. Biomass distribution was compared among four plant categories: vines, forbs, grasses, and woody. Moderate intensity treatments (chainsaw and shear and chop) consistently ranked highest overall in diversity, with the mature pine-hardwood forest ranking lowest. Distribution of the four plant categories was not significantly affected by intensity of site preparation.Alabama Agricultural Experiment Station Series No. 9-892325P.     

The potential drivers in forming avian biodiversity hotspots in the East Himalaya Mountains of Southwest China

Little has been published to describe or interpret Asian biodiversity hotspots, including those in the East Himalayan Mountains of Southwest China (HMSC), thus making necessary a review of the current knowledge. The Pliocene and Pleistocene geological and glacial histories of the Asian continent differ from those of Europe and North America, suggesting different mechanisms of speciation and extinction, and, thus, different responses to climate changes during the Quaternary glaciations. This short review summarizes potential drivers in shaping and maintaining high species richness and endemism of birds in the HMSC. The geographical location at the junction of different biogeographical realms, the wide range of habitats and climates along the extensive elevational range, the complex topography and the distinct geological history of this region have probably contributed to the evolution of an exceptionally species‐rich and endemic‐rich, specialized montane avian fauna. The Mountain systems in the HMSC may have provided refugia where species survived during the glacial periods and barriers for preventing species dispersal after the glacial periods. More studies are required to further test this refugia hypothesis by comparing more cold‐tolerent and warm‐tolerent species.     

Growth of American oysters increased by polyploidy induced by blocking meiosis I but not meiosis II

Triploidy in American oysters (Crassostrea virginica) was induced by blocking polar body formation with cytochalasin B. Triploid oysters created by treatment during meiosis I grew faster during the first 3 years of life than did diploid siblings. Triploid oysters created during meiosis II grew at the same rate as their controls. Because heterozygosity was higher in oysters created during meiosis I than in other groups, the increased growth must be due to heterozygosity rather than to triploidy per se.