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991.
Zachary L. Robinson Donovan A. Bell Tashi Dhendup Gordon Luikart Andrew R. Whiteley Marty Kardos 《Conservation biology》2021,35(2):666-677
Augmenting gene flow is a powerful tool for the conservation of small, isolated populations. However, genetic rescue attempts have largely been limited to populations at the brink of extinction, in part due to concerns over negative outcomes (e.g., outbreeding depression). Increasing habitat fragmentation may necessitate more proactive genetic management. Broader application of augmented gene flow will, in turn, require rigorous evaluation to increase confidence and identify pitfalls in this approach. To date, there has been no assessment of best monitoring practices for genetic rescue attempts. We used genomically explicit, individual-based simulations to examine the effectiveness of common approaches (i.e., tests for increases in fitness, migrant ancestry, heterozygosity, and abundance) for determining whether genetic rescue or outbreeding depression occurred. Statistical power to detect the effects of gene flow on fitness was high (≥0.8) when effect sizes were large, a finding consistent with those from previous studies on severely inbred populations. However, smaller effects of gene flow on fitness can appreciably affect persistence probability but current evaluation approaches fail to provide results from which reliable inferences can be drawn. The power of the metrics we examined to evaluate genetic rescue attempts depended on the time since gene flow and whether gene flow was beneficial or deleterious. Encouragingly, the use of multiple metrics provided nonredundant information and improved inference reliability, highlighting the importance of intensive monitoring efforts. Further development of best practices for evaluating genetic rescue attempts will be crucial for a responsible transition to increased use of translocations to decrease extinction risk. 相似文献
992.
Kaninga Belinda Lark R. Murray Chishala Benson H. Maseka Kakoma K. Sakala Godfrey M. Young Scott D. Tye Andrew Hamilton Elliott M. Watts Michael J. 《Environmental geochemistry and health》2021,43(9):3699-3713
Environmental Geochemistry and Health - A field experiment was undertaken on farmers’ fields adjacent to a large mine tailings dam in the Zambian mining town of Kitwe. Experimental plots were... 相似文献
993.
994.
In what circumstances do organizations react to changes in their operating environment by adopting proportionate policy responses? And drawing on institutional theory, what expectations can we formulate in relation to the proportionality of policy responses to climate change? These two research questions frame this article, which seeks to make new connections between the emerging perspective of proportionality in policy-making and existing institutional theories. We find that institutional theories are well suited to formulating expectations concerning the (dis)proportionality of policy responses, but their explanatory power can be further improved by taking the characteristics of specific climate policy problems into account. While there are many different problems nested in the ‘meta’ problem of climate change, we find that most of them have characteristics which suggest that policy under-reactions are more, not less likely. Amongst institutional theories, rational choice institutionalism provides the clearest expectation that proportionate policy responses are unlikely. Policy entrepreneurship is identified as one obvious way in which to stimulate proportionate policy responses, through fostering new ways of thinking within organizations. 相似文献
995.
996.
Lee W. Cooper Jacqueline M. Grebmeier I. L. Larsen Scott S. Dolvin Andrew J. Reed 《Chemistry and Ecology》1998,15(1):27-46
Extensive surveys of sediment burdens of radiocaesium, specifically 137Cs, and other radioactive contaminants in the Arctic during the 1990's, indicate that almost all anthropogenic radionuclides buried on continental shelves adjacent to Alaska are derived from global bomb fallout. the 137Cs (half-life: 30.2y) activities observed in surface (0-4 cm) marine sediments however, vary widely, albeit much less than the expected current inventory resulting from bomb fallout at this latitude (∼100mBq cm-2). This observed geographical variation provided the opportunity to evaluate physical and biological mechanisms that may affect caesium biogeochemistry on Arctic continental shelves. We investigated whether high biological productivity in portions of the Bering and Chukchi Seas is effective in removing dissolved radiocaesium from the water column, and whether biological production in overlying water affects total radiocaesium inventories in sediments. Based upon C/N ratios in the organic fraction of shallow sediments, we found no evidence that higher inventories or surface activities of radiocaesium are present in areas with higher deposition of particulate organic matter. Based upon stable carbon isotope ratios of organic matter in sediments, we found no evidence that terrestrial runoff contributes proportionally to higher surface activities, although terrestrial runoff may affect total inventories of the radionuclide. Radiocaesium content of surface sediments was significantly correlated with total organic carbon content of sediments and the proportion of sediments in the finest sediment fractions. Because high current flow can also be expected to influence distributions of those sedimentary parameters, we conclude that re-distribution of 相似文献
997.
Robert M. Chiles Eileen E. Fabian Daniel Tobin Scott J. Colby S. Molly DePue 《Journal of Agricultural and Environmental Ethics》2018,31(3):341-348
The purpose of this paper is to provide further clarity to the technical and policy difficulties associated with mitigating greenhouse gas emissions from agriculture by identifying and distilling the core tensions which propagate and animate them. We argue that these complexities exist across four critical dimensions: the epistemological, the ethical, the political, and the practical. Adequately confronting the challenge of agricultural emissions will require improved transparency in emissions measurement, increased science communication, enhanced public participatory mechanisms, and the integration of ethical deliberation in scientific and policy discussions. 相似文献
998.
Robert Andrew Gilmer 《Environmental management》2013,52(5):1046-1056
Rather than exploring how indigenous people have been alienated from resources by environmental policies, this paper explores how indigenous peoples have worked with environmental organizations to use the broad protections provided by environmental laws to protect cultural resources. The Eastern Band of Cherokee Indians, along with other concerned groups, partnered with environmentalists in opposing the destruction of the endangered snail darter’s critical habitat by the Tennessee Valley Authority’s Tellico Dam. The dam had been opposed by a shifting alliance of Cherokees, local farmers, trout fisherman, and environmentalists since it was announced in 1963. A previous lawsuit by this coalition delayed the project from 1972 to 1974 under the National Environmental Policy Act. The Endangered Species Act provided this coalition with a powerful tool for opposing the destruction of burial grounds and sacred village sites throughout the lower Little Tennessee River valley. The coalition of environmental organizations, Cherokees, and others was ultimately unsuccessful in stopping the dam from being built, but was successful in establishing a strict precedent for the enforcement of the Endangered Species Act. The lawsuit also created a space for the Eastern Band to negotiate for the return of Cherokee remains and halt the removal of any additional burials. In this situation, the strategic support of environmental regulation enabled the Eastern Band to exert some degree of control over the fate of cultural resources in the valley, and also demonstrates the significant role American Indian peoples played in one of the seminal events of the environmental movement during the 1970s. 相似文献
999.
Aderibigbe Abiodun D. Stewart Alex G. Hursthouse Andrew S. 《Environmental geochemistry and health》2018,40(1):395-413
Environmental Geochemistry and Health - A multidisciplinary approach to research affords the opportunity of objectivity, creation of new knowledge and potentially a more generally acceptable... 相似文献
1000.
Nicholas L. Ortodossi Ben L. Gilby Thomas A. Schlacher Rod M. Connolly Nicholas A. Yabsley Christopher J. Henderson Andrew D. Olds 《Conservation biology》2019,33(3):580-589
Seascape connectivity (landscape connectivity in the sea) can modify reserve performance in low-energy marine ecosystems (e.g., coral reefs, mangroves, and seagrass), but it is not clear whether similar spatial linkages also shape reserve effectiveness on high-energy, exposed coastlines. We used the surf zones of ocean beaches in eastern Australia as a model system to test how seascape connectivity and reserve attributes combine to shape conservation outcomes. Spatial patterns in fish assemblages were measured using baited remote underwater video stations in 12 marine reserves and 15 fished beaches across 2000 km of exposed coastline. Reserve performance was shaped by both the characteristics of reserves and the spatial properties of the coastal seascapes in which reserves were embedded. Number of fish species and abundance of harvested fishes were highest in surf-zone reserves that encompassed >1.5 km of the surf zone; were located < 100 m to rocky headlands; and included pocket beaches in a heterogeneous seascape. Conservation outcomes for exposed coastlines may, therefore, be enhanced by prioritizing sufficiently large areas of seascapes that are strongly linked to abutting complementary habitats. Our findings have broader implications for coastal conservation planning. Empirical data to describe how the ecological features of high-energy shorelines influence conservation outcomes are lacking, and we suggest that seascape connectivity may have similar ecological effects on reserve performance on both sheltered and exposed coastlines. 相似文献