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561.
A. Catherine Markham Vishwesha Guttal Susan C. Alberts Jeanne Altmann 《Behavioral ecology and sociobiology》2013,67(6):875-884
Intraspecific competition is a key factor shaping space-use strategies and movement decisions in many species, yet how and when neighbors utilize shared areas while exhibiting active avoidance of one another is largely unknown. Here, we investigated temporal landscape partitioning in a population of wild baboons (Papio cynocephalus). We used global positioning system (GPS) collars to synchronously record the hourly locations of five baboon social groups for ~900 days, and we used behavioral, demographic, and life history data to measure factors affecting use of overlap areas. Annual home ranges of neighboring groups overlapped substantially, as predicted (baboons are considered non-territorial), but home ranges overlapped less when space use was assessed over shorter time scales. Moreover, neighboring groups were in close spatial proximity to one another on fewer days than predicted by a null model, suggesting an avoidance-based spacing pattern. At all time scales examined (monthly, biweekly, and weekly), time spent in overlap areas was greater during time periods when groups fed on evenly dispersed, low-quality foods. The percent of fertile females in social groups was negatively correlated with time spent in overlap areas only during weekly time intervals. This suggests that broad temporal changes in ecological resources are a major predictor of how intensively overlap areas are used, and groups modify these ecologically driven spacing patterns at short time scales based on female reproductive status. Together, these findings offer insight into the economics of territoriality by highlighting the dynamics of spacing patterns at differing time scales. 相似文献
562.
Using a Pathways approach, controversies over environmental and natural resource management are viewed as expressions of alternative, or competing, pathways to sustainability. This supports deeper understanding of the underlying causes of natural resource management controversies. The framework is composed of two elements: the STEPS (Social, Technological, and Environmental Pathways to Sustainability) Pathways approach and frame analysis. Many sustainable development dilemmas are played out in specific places and consequently, the Pathways approach is integrated with a place-based frame analysis. The resulting framework guides empirical investigation in place-based contexts. This theorising about sustainability science can be used to cast light on contested natural resource management issues, in this case mining in northern Sweden. By exposing the range of alternative Pathways to critical norms of sustainable development, we ascertain whether action alternatives are compatible with sustainable futures. The framework provides a way in which sustainability science can better understand the origins of natural resource management conflicts, characterise the positions of the actors involved, identify the potential for cooperation between stakeholders leading to policy resolution and judge what Pathways help or hinder the pursuit of sustainable development. In addition, it can enhance sustainability science by guiding integrative sustainability research at the project scale. 相似文献
563.
Composting toilets aim to recycle excrement into safe, stable humus. Preceding this, low costs, low risks, and mass reduction should be ensured. Source separating vermicomposting toilets (SSVCs) outperformed mixed latrine microbial composting toilets (MLMCs) in all categories. MLMCs: incurred ten times greater operational costs; created 10x more operator exposure; employed no proven pathogen reduction mechanism since solid end-products averaged 71,000 ± 230,000 CFU/g (fecal-origin) Escherichia coli and 24 ± 5% total solids, consistently failed NSF/ANSI Standard 41; failed to reduce volatile solids compared to raw fecal matter; increased total contaminated dry mass by 274%, and produced alkaline end-product (8.0 ± 0.7) high in toxic free ammonia (Solvita® 2.6 ± 1.5). SSVCs have low maintenance costs and risks; adequate worm density for pathogen destruction (0.03 ± 0.04 g-worm/g-material); reduced E. coli 200 ± 244 CFU/g in neutral (7.4 ± 0.3), stable (60 ± 10% volatile solids), and mature (4 ± 0 Solvita® NH3) end-product. 相似文献
564.
Patterns of Genetic Diversity in Remaining Giant Panda Populations 总被引:12,自引:0,他引:12
Zhi Lu † Warren E. Johnson Marilyn Menotti-Raymond Naoya Yuhki Janice S. Martenson Susan Mainka ‡ Huang Shi-Qiang § Zheng Zhihe Guanghan Li Wenshi Pan † Xiarong Mao † Stephen J. O'Brien†† 《Conservation biology》2001,15(6):1596-1607
Abstract: The giant panda ( Ailuropoda melanoleuca ) is among the more familiar symbols of species conservation. The protection of giant panda populations has been aided recently by the establishment of more and better-managed reserves in existing panda habitat located in six mountain ranges in western China. These remaining populations are becoming increasingly isolated from one another, however, leading to the concern that historic patterns of gene flow will be disrupted and that reduced population sizes will lead to diminished genetic variability. We analyzed four categories of molecular genetic markers (mtDNA restriction-fragment-length polymorphisms [RFLP], mtDNA control region sequences, nuclear multilocus DNA fingerprints, and microsatellite size variation) in giant pandas from three mountain populations (Qionglai, Minshan, and Qinling) to assess current levels of genetic diversity and to detect evidence of historic population subdivisions. The three populations had moderate levels of genetic diversity compared with similarly studied carnivores for all four gene measures, with a slight but consistent reduction in variability apparent in the smaller Qinling population. That population also showed significant differentiation consistent with its isolation since historic times. From a strictly genetic perspective, the giant panda species and the three populations look promising insofar as they have retained a large amount of genetic diversity in each population, although evidence of recent population reduction—likely from habitat loss—is apparent. Ecological management to increase habitat, population expansion, and gene flow would seem an effective strategy to stabilize the decline of this endangered species. 相似文献
565.
Effects of Habitat Size and Patch Isolation on Reproductive Success of the Serpentine Morning Glory 总被引:7,自引:0,他引:7
Abstract: We examined the effects of habitat area and patch isolation on reproductive success in serpentine morning glory ( Calystegia collina [Convolvulaceae]), a primarily self-incompatible clonal plant endemic to serpentine outcrops in northern California's coast ranges. Within a 4000-km 2 region, we compared the reproductive success of C. collina on 16 small (<5 ha) and 7 large ( >300 ha) outcrops. Flower and fruit production were significantly higher on large serpentine outcrops than on small outcrops. Fruit production also was positively correlated with the soil's ratio of calcium to magnesium. Successful pollination was positively affected by flower density and the number of other flowering patches within 100 m of a C. collina patch. The number of nearby flowering patches was considerably higher on large than on small outcrops. Flowers on large outcrops did not receive significantly more bee visitors than flowers on small outcrops, suggesting that pollination success is related to the quality rather than the quantity of pollen deposited. Fruit production by plants on both small and large outcrops was enhanced by the experimental addition of pollen from other patches, but not by the addition of pollen from the same patch. These findings demonstrate that the size of habitat may have strong effects on the reproductive success of locally endemic plants by enhancing opportunities for successful sexual reproduction. They also warn against the presumption that naturally patchy plant species are invulnerable to the effects of habitat fragmentation. 相似文献
566.
Susan L. Woodward 《Disasters》2001,25(4):331-344
The NATO bombing operation Allied Force against Yugoslavia in March-June 1999 represents the final disappearance of the narrowing divide between humanitarianism and politics: a war initiated and justified on humanitarian grounds. Although unlikely to be repeated any time soon, the Kosovo case appears to have cemented an ideological shift on the international right and even necessity of sing military force to protect civilians within sovereign states. Rather than humanitarians acknowledging the political context and consequences of their work, however, the case suggests the embrace of humanitarian principles of universality and neutrality by military organisations. This article discusses some consequences of the new consensus: neglect of the political context (both local and foreign) of such operations, interaction between the operational dynamics of relief operations and the logic of war and the political consequences of using the humanitarian legitimation and mission in such cases. 相似文献
567.
568.
Trophic dynamics of U, Ni, Hg and other contaminants of potential concern on the Department of Energy’s Savannah River Site 总被引:1,自引:0,他引:1
Paul G. Edwards Karen F. Gaines A. Lawrence Bryan Jr. James M. Novak Susan A. Blas 《Environmental monitoring and assessment》2014,186(1):481-500
The Department of Energy’s Savannah River Site is a former nuclear weapon material production and current research facility located in South Carolina, USA. Wastewater discharges from a fuel and nuclear reactor target manufacturing facility released depleted and natural U, as well as other metals into the Tims Branch-Steed Pond water system. We investigated the current dynamics of this system for the purposes of environmental monitoring and assessment by examining metal concentrations, bioavailability, and trophic transfer of contaminants in seven ponds. Biofilm, detritus, and Anuran and Anisopteran larvae were collected and analyzed for stable isotopes (δ 15N, δ 13C) and contaminants of potential concern (COPC) with a focus on Ni, U, and Hg, to examine metal mobility. Highest levels of Ni and U were found in biofilms U (147 and 332 mg kg?1 DW, respectively), while highest Hg levels were found in tadpoles (1.1 mg kg?1 DW). We found intraspecific biomagnification of COPCs as expressed through stable isotope analysis. Biofilms were the best indicators for contamination and Anuran larvae with the digestive tract removed were the best indicators of the specific bioavailability of the focal metals. Monitoring data showed that baseline δ 15N values differed between ponds, but within a pond, values were stable throughout tadpole Gosner stage, strengthening the case to use this species for monitoring purposes. It is likely that there still is risk to ecosystem integrity as COPC metals are being assimilated into lower trophic organisms and even low levels of this mixture has shown to produce deleterious effects to some wildlife species. 相似文献
569.
Gustin MS Chavan PV Dennett KE Marchand EA Donaldson S 《Journal of environmental quality》2006,35(6):2352-2359
Mercury associated with natural enrichment, historic mining, and ore processing is a contaminant of concern in watersheds of the western USA. In this region, water is a highly managed resource and wetlands, known to be important sites of methyl mercury production, are often an integral component of watersheds. This study applied controlled manipulations of four replicated experimental wetland designs with different water and soil mercury concentrations to determine the potential impacts on methyl mercury export. Wetlands were manipulated by drying and wetting, changing hydraulic retention time, and adding sulfate and nitrate to influent waters. In a summer drying and wetting manipulation, an immediate increase in total methyl mercury release was observed with rewetting, however, concentrations decreased quickly. Drying all wetlands over the winter and rewetting in the spring resulted in high net methyl mercury output relative to that observed before drying. Net methyl mercury output was not influenced by changes in hydraulic retention time from 4 to 8 h or to 30 min, or by increasing the nitrate concentration from 0.1 to 10 mg L(-1). The addition of sulfate to the inlet waters of two mesocosms to increase concentrations from approximately 100 to 250 mg L(-1) did not result in a clear effect on methyl mercury output, most likely due to sulfate concentrations being higher than optimal for methyl mercury production. Despite the lack of response to sulfate amendments, the change in sulfate concentration between the inlet and outlet of the mesocosms and temperature were the parameters best correlated with methyl mercury outputs. 相似文献
570.