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971.
Demographic structure and its seasonal dynamics have been studied in colonies of narrow-skulled voles (Lasiopodomys gregalis Pall.) in Northern Kulunda. Three types of colonies have been distinguished: (I) true colonies (large, complex families), (II) simple families (nuclear or incomplete), and (III) all-male colonies. Changes in their sex, age, and functional composition (based on animal migration activity) during the breeding season have been analyzed.  相似文献   
972.
With globalization, virtual exchanges of natural resources embodied in traded commodities redistribute geographically land use and its environmental impacts. Benefits of national forest protection may be undermined at the global-scale by leakage through international trade. We studied land use displacement associated with national policies to protect forests in Bhutan. This case study provides a simple situation: a dominant forest cover almost unaffected by agricultural expansion, a rural economy dominated by the primary sector, centralized forest conservation policies, and a dominant trading partner. We assessed the net effects at the international level of the Bhutanese forest protection policies by accounting for trade in wood products with India. Our results show that these policies have been effective in maintaining a high forest cover, but have been accompanied by an increasing displacement of forest use to India. In 1996–2011, the difference between the total volume of wood imported from India and the total volume exported from Bhutan—i.e., the net displacement—corresponds to 27 % of the total volume consumed in Bhutan. In 2011, 68 % of the total forest area required to produce the wood consumed in Bhutan was located in India. The wood imported by Bhutan was likely originating from tree plantations in the northeastern Indian states. Since Bhutan has few tree plantations and very valuable natural forests, the net international-level ecological impacts of this land use displacement is arguably positive. Most of the wood imports of Bhutan were wood charcoal for its emerging chemical industries. This case of displacement reflects functional upgrading in the value-chain rather than an externalization of consumption-based environmental costs. Through its government policies, Bhutan has managed to support its economic development while protecting its forests and leapfrogging the negative impacts on forests generally associated with the early stages of modernization.  相似文献   
973.
This study takes an historical approach in order to establish how the form and function of the social-ecological system that represents the Bangladesh south-western coastal zone has changed over recent decades. Time series data for a range of ecosystem services and drivers are analysed to define the range of trends, the presence of change points, slow and fast variables and the significant drivers of change. Since the 1980s, increasing gross domestic product and per capita income mirror rising levels of food and inland fish production. As a result, the size of population below the poverty line has reduced by ~17 %. In contrast, non-food ecosystem services such as water availability, water quality and land stability have deteriorated. Conversion of rice fields to shrimp farms is almost certainly a factor in increasing soil and surface water salinity. Most of the services experienced statistically significant change points between 1975 and 1980, and among the services, water availability, shrimp farming and maintenance of biodiversity appear to have passed tipping points. An environmental Kuznets curve analysis suggests that the point at which growing economic wealth feeds back into effective environmental protection has not yet been reached for water resources. Trends in indicators of ecosystem services and human well-being point to widespread non-stationary dynamics governed by slowly changing variables with an increased likelihood of systemic threshold changes/tipping points in the near future. The results will feed into simulation models and strategies that can define alternative and sustainable paths for land management.  相似文献   
974.
Fire history within the northern larch forests of Central Siberia was studied (65 + °N). Fires within this area are predominantly caused by lightning strikes rather than human activity. Mean fire return intervals (FRIs) were found to be 112 ± 49 years (based on firescars) and 106 ± 36 years (based on firescars and tree natality dates). FRIs were increased with latitude increase and observed to be about 80 years at 64°N, about 200 years near the Arctic Circle and about 300 years nearby the northern range limit of larch stands (~71° + N). Northward FRIs increase correlated with incoming solar radiation (r = ?0.95). Post-Little Ice Age (LIA) warming (after 1850) caused approximately a doubling of fire events (in comparison with a similar period during LIA). The data obtained support a hypothesis of climate-induced fire frequency increase.  相似文献   
975.
Our research addresses the gap in scientific research on the fine-grain spatial patterns and social–ecological interactions of land use and agrobiodiversity. The spatial dimension of agrobiodiversity dynamics potentially strengthens the social–ecological resilience and food security of smallholders by buffering risk and vulnerability. Our research integrates the scientific theories, concepts, and methods of spatial externalities, social–ecological interactions, geospatial land and global change sciences, and political ecology. We designed a case study of the Arbieto-Tarata landscape in the Bolivian Andes that comprises a globally significant agrobiodiversity hot spot of Andean maize. The Arbieto-Tarata landscape, which contains nearly 8000 fields at 2500–2800 masl, is representative of mixed-use smallholder agri-food systems amid global changes. Our research predicts spatial spillover and edge effects of combined social and environmental factors leading to the clustering of same-crop fields. Findings reveal significant levels of the predicted clustering between 2006 and 2012. The degree of this clustering is found to differ among geographic and environmental sub-areas reflecting fine-grain variation of local causal linkages. Extra-local causal linkages include high levels of migration, water resource shortages, and urbanization. Results show the influences of informal and formal coordination in the spatial clustering of same-crop fields. This field-level coordination improves the efficiency of resource allocations and lowers costs of production. It enables the viability of high-agrobiodiversity Andean maize in smallholder land use and agri-food systems amid global changes. The article discusses the broader policy and scientific implications of these findings including scaling up and support of the social–ecological resilience of agrobiodiversity globally.  相似文献   
976.
Environmental restoration projects are commonly touted for their ecological positives, but such projects can also provide significant socioeconomic and cultural benefits to local communities. We assessed the social dimensions of a large-scale coral reef restoration project in Maunalua Bay, O‘ahu, where >1.32 million kg of invasive marine macroalgae was removed from 11 hectares (90,000 m2; 23 acres) of impacted coral reef in an urbanized setting. We interviewed 131 community stakeholders and analyzed both quantitative and qualitative data to assess human uses of the environment, assess perceptions of environmental health, and characterize social dimensions (+/?) associated with the invasive algae removal effort. Results indicate substantial direct economic benefits, including the creation of more than 60+ jobs, benefiting more than 250 individuals and 81 households. The project helped develop a skilled workforce in a local business dedicated to environmental restoration and increased the capacity of community organizations to address other threats to reefs and watersheds. Other major benefits include revitalization of Native Hawaiian cultural practices and traditions and the successful use of harvested invasive algae as compost by local farmers. Our results show the project heightened community awareness and a broader sense of stewardship in the area, creating enabling conditions for collective community action. Our findings show that restoration projects that explicitly incorporate efforts to build community awareness, involvement, and a shared responsibility for a site may ultimately create the long-term capacity for sustainable stewardship programs. We conclude by discussing lessons learned for engaging productively with communities in environmental restoration and stewardship, which remains a central focus in conservation worldwide.  相似文献   
977.
Though tiger conservationists almost ubiquitously acknowledge the necessity of landscape approaches and the involvement of local people for effective tiger conservation, reconciling these two needs presents certain challenges for practitioners. Seeking to address both local exigencies and conservation goals, state-sponsored ecodevelopment initiatives have become commonly associated with Project Tiger reserves in India. However, in this essay I argue that by focusing on the proximate sources of tension between tiger conservation and local people (i.e., human–tiger conflict, habitat degradation, and prey depletion), these programs have reinforced the ultimate causes of such tension: the structural inequalities that exists between local people and state organizations. By linking the historical literature with my own fieldwork in the Melghat Tiger Reserve of the Central Indian Highlands, I show how the current structure of ecodevelopment largely mirrors that of colonial forestry by attempting to enforce natural resource property rights in a way that privileges the state and delegitimizes local relational mechanisms of access to natural resources. In doing so, ecodevelopment reflects the political structure that facilitated the rise of conflicts between tigers and people and reinforces the “gridlock of tiger conservation” (Rastogi et al. 2012). With this political ecology perspective, I advocate solidarity between conservation practitioners, local people, and state organizations in addressing these structural problems to further conservation efforts. Emphasizing co-management’s ability to accommodate multi-scalar forms of authority, I end by offering three lessons for conservation from Melghat’s experience with colonial forestry and ecodevelopment.  相似文献   
978.
Large connected landscapes are paramount to maintain top predator populations. Across their range, tiger (Panthera tigris) populations occur in small fragmented patches of habitat, often isolated by large distances in human-dominated landscapes. We assessed connectivity between 16 protected areas (PAs) in central India, a global priority landscape for tiger conservation, using data on land use and land cover, human population density, and transportation infrastructure. We identified and prioritized movement routes using a combination of least-cost corridor modeling and circuit theory. Our analyses suggest that there are several opportunities to maintain connectivity in this landscape. We mapped a total of thirty-five linkages in the region and calculated metrics to estimate their quality and importance. The highest quality linkages as measured by the ratio of cost-weighted distance to Euclidean distance are Kanha–Phen/Bandhavgarh–SanjayGhasidas/Melghat–Satpura, and cost-weighted distance to least-cost path length are Nawegaon–Tadoba/Achanakmar–SanjayGhasidas/Kanha–Phen. We used current flow centrality to evaluate the contribution of each PA and linkage toward facilitating animal movement. Values are highest for Kanha and Pench tiger reserves, and the linkages between Kanha–Phen, Kanha–Pench, and Pench–Satpura, suggesting that these PAs and linkages play a critical role in maintaining connectivity in central India. In addition, smaller areas such as Bor, Nawegaon, and Phen have high centrality scores relative to their areas and thus may act as important stepping stones. We mapped pinch points, which are sections of the linkages where tiger movement is restricted due to unfavorable habitat, transportation networks, human habitation, or a combination of factors. Currently, very limited data exist on tiger movement outside of PAs to validate model results. Regional-scale connectivity mapping efforts can assist managers and policy makers to develop strategic plans for balancing wildlife conservation and other land uses in the landscape.  相似文献   
979.
Regional Environmental Change - The potential impact of climate change on port operations and infrastructures has received much less attention than the corresponding impact for beach systems....  相似文献   
980.
Human exposure to ambient ozone (O3) has been linked to a variety of adverse health effects. The ozone level at a location is contributed by local production, regional transport, and background ozone. This study combines detailed emission inventory, air quality modeling, and census data to investigate the source–receptor relationships between nitrogen oxides (NOx) emissions and population exposure to ambient O3 in 48 states over the continental United States. By removing NOx emissions from each state one at a time, we calculate the change in O3 exposures by examining the difference between the base and the sensitivity simulations. Based on the 49 simulations, we construct state-level and census region-level source–receptor matrices describing the relationships among these states/regions. We find that, for 43 receptor states, cumulative NOx emissions from upwind states contribute more to O3 exposures than the state's own emissions. In-state emissions are responsible for less than 15% of O3 exposures in 90% of U.S. states. A state's NOx emissions can influence 2 to 40 downwind states by at least a 0.1 ppbv change in population-averaged O3 exposure. The results suggest that the U.S. generally needs a regional strategy to effectively reduce O3 exposures. But the current regional emission control program in the U.S. is a cap-and-trade program that assumes the marginal damage of every ton of NOx is equal. In this study, the average O3 exposures caused by one ton of NOx emissions ranges from ? 2.0 to 2.3 ppm-people-hours depending on the state. The actual damage caused by one ton of NOx emissions varies considerably over space.  相似文献   
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