Dynamics of Tree and Shrub Vegetation in the Eastern Sayan Mountain Tundra

Russian Journal of Ecology - Climate change entails shifts in the ranges of woody plants along both latitudinal and altitudinal gradients in the boreal forest biome. In this study,...     

Emergency centers in Israel: A small community organizes to cope with war related crises*

This paper focuses on community-wide emergencies caused by war-related events in Lebanon at the beginning of June 1982. Mobilization for the "Peace for Galilee" campaign began on Friday, 4th June. Overnight, families were disrupted, husbands and sons were in danger, and within 24 hours there were notifications of casualities and deaths. Families in crisis became a widespread phenomenon. In Herzlia, as in many other communities, a new service - the Emergency Center - emerged under the auspices of the Ministry of Labor and Social Affairs and the Municipality. The authors describe this process of getting organized, the populations served, how the Center was staffed, the role of citizen volunteers, and the types of interventions used to help vulnerable families as well as soldiers home on leave. Stress is placed on the unique type of short-term co-operation achieved between social workers of the local Department of Social Welfare, the staff of the Department of Community Services (especially its Volunteer Bureau), the local liason officer of the Israel Defence Force, the municipal government, and public-spirited volunteers. Mention is made of conditions which made possible the activation of such a service within hours, of the Center's capacity to serve all segments of the population, and of how it was deactivated within a few weeks when the emergency ended. On the basis of lessons learned from this experience, the paper ends with a number of specific recommendations. The authors hope that such innovative forms of crisis-intervention will become part of the helping technology widely available at the community level in future years.     

Spatial and temporal patterns of predation on seeds of the surfgrass Phyllospadix torreyi

Spatial and temporal patterns of predation on seeds of the seagrass Phyllospadix torreyi S. Watson were quantified at four sites near Santa Barbara, California, USA. Over a period of four flowering seasons during 1995 to 1998, monthly patterns of seed fall and intensity of seed predation were similar among sites, but were temporally quite variable. Abundance of dispersed seeds varied greatly both among seasons and years. Within any one year, seeds were present in the environment every month, but they peaked in abundance during the fall months following the annual flowering period. Seeds were more abundant during the earlier years of the study. The intensity of predation steadily increased throughout the study period, from a low of ≤10% seeds consumed during 1995 to ∼50% consumption by 1997, and it was not correlated with abundance of seeds in the environment. Pre-dispersal seed loss also was estimated in two flowering seasons by counting the numbers of seeds consumed prior to release from the plant, and was relatively low (<15%). No differences were detected among the four study sites in patterns of pre-dispersal loss. Field surveys were done at two sites to identify potential seed predators. Three of the most abundant species identified in these surveys were tested in the laboratory to determine size-specific patterns of feeding activity and to assess which early life stages of P. torreyi (fruits within spadices, dehisced fruits, seedlings) were most vulnerable to predation. All three of the early life stages were consumed. The crabs Pugettiaproducta (Randall) and Pachygrapsus crassipes Randall were much more voracious predators than the isopod Idotea resecata Stimpson. Received: 8 June 1999 / Accepted: 2 February 2000     

Genomic erosion in a demographically recovered bird species during conservation rescue

The pink pigeon (Nesoenas mayeri) is an endemic species of Mauritius that has made a remarkable recovery after a severe population bottleneck in the 1970s to early 1990s. Prior to this bottleneck, an ex situ population was established from which captive-bred individuals were released into free-living subpopulations to increase population size and genetic variation. This conservation rescue led to rapid population recovery to 400–480 individuals, and the species was twice downlisted on the International Union for the Conservation of Nature (IUCN) Red List. We analyzed the impacts of the bottleneck and genetic rescue on neutral genetic variation during and after population recovery (1993–2008) with restriction site-associated sequencing, microsatellite analyses, and quantitative genetic analysis of studbook data of 1112 birds from zoos in Europe and the United States. We used computer simulations to study the predicted changes in genetic variation and population viability from the past into the future. Genetic variation declined rapidly, despite the population rebound, and the effective population size was approximately an order of magnitude smaller than census size. The species carried a high genetic load of circa 15 lethal equivalents for longevity. Our computer simulations predicted continued inbreeding will likely result in increased expression of deleterious mutations (i.e., a high realized load) and severe inbreeding depression. Without continued conservation actions, it is likely that the pink pigeon will go extinct in the wild within 100 years. Conservation rescue of the pink pigeon has been instrumental in the recovery of the free-living population. However, further genetic rescue with captive-bred birds from zoos is required to recover lost variation, reduce expression of harmful deleterious variation, and prevent extinction. The use of genomics and modeling data can inform IUCN assessments of the viability and extinction risk of species, and it helps in assessments of the conservation dependency of populations.     

Biological factors affecting the swimbladder volume of sardine (Sardina pilchardus)

Variations in the absolute and relative swimbladder volume of sardine (Sardina pilchardus W.), were examined in relation to fish length, gonads and stomach volume, and lipid content. Fifty specimens were frozen in liquid nitrogen and sliced with a cryo-microtome. From the slices, volume estimates of the organs were obtained through computer reconstruction. Variations in absolute and relative swimbladder volume in relation to fish length and the aforementioned organs' volume and lipid contents were estimated by means of multiple regression analysis. The relative importance of these variables in the calculations of the swimbladder volume for different physiological conditions of the fish was also assessed. The results revealed that the volume can be estimated from two distinct models: the first for the reproductive and the second for the non-reproductive period. The non-reproductive period model is in agreement with the well-known positive correlation of target strength with fish log length. However, during the reproductive period the relative size of gonads and relative lipid content gradually become more important than length.     

燃煤电厂排放颗粒物中重金属形态的研究

本文分析用模拟酸雨浸提和Ｔｅｓｓｉｅｒ形态分离法，对燃煤电厂排放颗粒物中重金属形态进行了研究。结果表明，痕量金属绝大部分以稳定态存在，微米级飞灰中有较大活性的形态高于灰渣，煤燃烧高温条件使颗粒物中活性较大的形态含量减小。