Structural chromosomal polymorphism in the dog-whelk Nucella lapillus (Mollusca: Neogastropoda)

On the English and French Channel coasts, the dog-whelk Nucella lapilus (L.) exhibits variation in chromosome number which appears to correlate with the degree of wave action on the shore. The more common, 2n=26 morph is typically found on exposed shores subjected to a high degree of wave action, whereas those with higher chromosome numbers, up to the recorded maximum of 2n=36, are restricted to more sheltered environments. The polymorphism is thought to be Robertsonian in nature, involving centric (centromere) fission or fusion, but detailed analysis of the polymorphism has been restricted by lack of success in labelling individual chromosomes. Using a silver-staining technique for the nucleolar organiser regions (NORs), three pairs of chromosomes, in the basic 2n=26 karyotype, have been positively identified. A series of structural chromosomal rearrangements (pericentric and paracentric inversions) affecting one pair of chromosomes involved in the numerical polymorphism is described. Significant differences exist between populations with respect to this character. These chromosomal rearrangements have the potential to reduce the level of interbreeding between the different types, and may act as isolating mechamisms between breeding groups. Structural chromosomal polymorphism is likely, therefore, to have greater significance in relation to adaptation than simple numerical variation. This finding raises important questions concerning the (cyto)taxonomic status of N. lapillus in different parts of its range.     

Perceptual Indicators of Environmental Health, Future Land Use, and Stewardship

There are important linkages between the health of humans and theenvironment, restoration of degraded lands, and long-term stewardship of public lands, yet most environmental indicators deal only with assessing the physical and biological aspects ofecosystems. In this article, we examine the ratings of perceptionsof several environmental problems for their utility as indicatorsof environmental quality, and examine perceptions of future land use by people interviewed in Santa Fe, New Mexico, near the Department of Energy's (DOE) Los Alamos National Laboratory (LANL). Overall, people with lower incomes rated environmental problems as more severe than others, were more willing to spend federal funds to solve them, and were consistent in their ratingsof severity of environmental problems and their willingness to spend federal funds. Cleaning up LANL and other Department of Energy sites, received the highest rating for expenditure of federal funds. The highest rated future uses for DOE sites were for recreation and for National Environmental Research Parks. People with less education generally gave higher ratings to mostfuture land uses for DOE than did those with more education. However, those with higher education gave higher ratings to nuclear reprocessing, and nuclear material storage. Where there were differences, the people interviewed at Santa Fe rated all environmental problems (except pesticides) as more severe than did those previously interviewed in Albuquerque (located fartherfrom the LANL site), and they were more willing to spend federalfunds on these problems. Ratings for all future land uses did notdiffer between the Santa Fe and Albuquerque respondents. These perception-based indicators show general agreement among peopleliving close and farther away from LANL with respect to cleaningup LANL and the future land uses for the site. These indicators should be considered by regulators, site personnel, and policy makers in future management and land use decisions.     

Kinetics of uranium uptake in soft water and the effect of body size,bioaccumulation and toxicity to Hyalella azteca

The kinetics of uptake and the effect of body size on uranium (U) bioaccumulation and toxicity to Hyalella azteca exposed to water-only U concentrations in soft water were evaluated. The effect of body size on U bioaccumulation was significant with a slope of ?0.35 between log body concentration and log body mass. A saturation kinetic model was satisfactory to describe the uptake rate, elimination rate and the effect of gut-clearance on size-corrected U bioaccumulation in H. azteca. The one-week lethal water concentrations causing 50% mortality for juvenile and adult H. azteca were 1100 and 4000 nmol U/L, respectively. The one-week lethal body concentration causing 50% mortality was 140 nmol U/g for juvenile H. azteca and 220 nmol U/g for adult H. azteca. One-week bioaccumulation studies that properly account for body-size and gut-clearance times can provide valuable data on U bioavailability and toxicity in the environment.     

Saturation models of arsenic, cobalt, chromium and manganese bioaccumulation by Hyalella azteca

Bioaccumulation of As, Co, Cr and Mn by the benthic amphipod Hyalella azteca in Burlington City tap (Lake Ontario) water was measured in 4-week tests. Bioaccumulation increased with exposure concentration and demonstrated an excellent fit to a saturation model (r(2): 0.819, 0.838, 0.895 and 0.964 for As, Co, Cr and Mn, respectively). The proportion of total body Mn eliminated during a 24-h depuration period decreased as Mn body concentration increased, apparently due to a saturation of the elimination rate. The high maximum body concentration of 116,000 nmol g(-1) appears to result from the saturation of the Mn excretion which is slightly greater than the maximum Mn uptake rate. Elimination rates for As, Co and Cr were not dependent on body concentration. The four elements were not physiologically regulated in Hyalella. Their body concentrations should be good indicators of bioavailability and useful for environmental assessment.     

东非地区的海洋保护区：它们取得了多大的成功?

本文探讨了东非地区海洋保护区(MPA)及其所包含的珊瑚礁的管理。这一地区包括科摩罗、肯尼亚、马达加斯加、毛里求斯、莫桑比克、坦桑尼亚以及塞舌尔。     

系统改革商界面临的最大挑战与机遇

商界领袖们投入几乎所有的时间在经济和政治系统内运作，遵守着这些系统内部的“游戏规则”。他们很少考虑这样构一些问题，比如：这些规则正确吗？究竟是什么潜在的假设在指导着经济和政治系统？商业最终的目标和意图是什么？我们是在实现这个目：际和意图的过程中吗？如果不是，原因何在？什么需要改变？     

Mitigation and Adaptation Strategiesfor Global Change Editorial Policy Update2003

Mitigation and Adaptation Strategies for Global Change -     

Creating local institutional arrangements for sustainable wetland socio-ecological systems: lessons from the ‘Striking a Balance’ project in Malawi

Wetland socio-ecological systems provide livelihood benefits for many poor people throughout the developing world, yet their sustainable development requires local utilisation strategies that balance both environmental and development outcomes. Community-based local institutional arrangements that mediate peoples’ relationships with their environment and facilitate adaptive co-management offer one means of achieving this, and increasingly many NGOs and development practitioners have sought to integrate local institutional capacity building into development projects. In the context of wider academic debates surrounding the long-term sustainability of externally facilitated local institutions, this article draws on the experiences of the three-year Striking a Balance (SAB) project in Malawi which sought to embed sustainable wetland management practices within community-based local institutional arrangements. Drawing on field data collected through participatory methods at three project sites some 5 years after the cessation of project activities, we examine the extent to which SAB’s local institutional capacity building has been successful, and from this draw some lessons for externally driven project interventions which seek win-win outcomes for people and the environment. With reference to Elinor Ostrom’s design principles for long-enduring common property resource institutions, we suggest that the observed declining effectiveness of SAB’s local institutions can be attributed to issues of stakeholder inclusiveness and representations; their sustainability was arguably compromised from their inception on account of them being nested within pre-existing, externally driven village ‘clubs’ whose membership and decision-making was not congruent with all the wetland stakeholders within the community.     

CERES — A model of forest stand biomass dynamics for predicting trace contaminant,nutrient, and water effects. II. Model application

In a previous paper (Dixon et al., 1978) the ecosystem model, CERES, was described. In this paper an application of CERES is presented to show the versatility of the model and its capability to simulate solute transport. Simulation results for 10 days in May illustrate the hourly patterns of photosynthesis, leaf sugar levels and translocation. A 1-year simulation shows seasonal dynamics of biomass fluxes in plants and litter.The third simulation shows the effects of a lead mine-smelter complex on an oak-hickory forest in southeastern Missouri. Results from a 6-year simulation with CERES coupled with other models in the Unified Transport Model illustrate toxic metal effects on litter decomposition and slight reduction of root growth with the parameters chosen. Heavy metal pollutants from the lead mine and smelter complex were introduced to the ecosystem as wetfall and dryfall. The DRYADS and DIFMAS models calculated the heavy metal uptake by the vegetation and accumulation in litter. During the 6-year period, the steady annual input of plant litter and the reduced decomposition rate resulted in an increase in litter mass of nearly 50%.