Long-term population declines have elevated recovery of grassland avifauna to among the highest conservation priorities in North America. Because most of the Great Plains is privately owned, recovery of grassland bird populations depends on voluntary conservation with strong partnerships between private landowners and resource professionals. Despite large areas enrolled in voluntary practices through U.S. Department of Agriculture's Lesser Prairie-chicken (Tympanuchus pallidicinctus) Initiative (LPCI), the effectiveness of Farm Bill investments for meeting wildlife conservation goals remains an open question. Our objectives were to evaluate extents to which Conservation Reserve Program (CRP) and LPCI-grazing practices influence population densities of grassland birds; estimate relative contributions of practices to regional bird populations; and evaluate percentages of populations conserved relative to vulnerability of species. We designed a large-scale impact-reference study and used the Integrated Monitoring in Bird Conservation Regions program to evaluate bird population targets of the Playa Lakes Joint Venture. We used point transect distance sampling to estimate density and population size for 35 species of grassland birds on private lands enrolled in native or introduced CRP plantings and LPCI-prescribed grazing. Treatment effects indicated CRP plantings increased densities of three grassland obligates vulnerable to habitat loss, and LPCI grazing increased densities of four species requiring heterogeneity in dense, tall-grass structure (α = 0.1). Population estimates in 2016 indicated the practices conserved breeding habitat for 4.5 million birds (90% CI: 4.0–5.1), and increased population sizes of 16 species , totaling 1.8 million birds (CI: 1.4–2.4). Conservation practices on private land benefited the most vulnerable grassland obligate species (AICc weight = 0.53). By addressing habitat loss and degradation in agricultural landscapes, conservation on private land provides a solution to declining avifauna of North America and scales up to meet population recovery goals for the most imperiled grassland birds. 相似文献
The impacts of natural hazards are typically measured in terms of loss of human lives and economic damage, and recent studies demonstrate that deaths attributed to natural hazards have increased. Using the publicly available DesInventar database, we examined spatial and temporal patterns of natural hazard mortality from 1971 to 2011 at the district and village levels of Nepal and identified natural hazards that contributed most to mortality. Spatial clusters of mortality at the district and village levels were detected using local and global spatial autocorrelation measures (Moran's I). Landslides (41.91%) and floods (32.52%) accounted for approximately three quarters of natural hazard mortalities over the study period. A Global Moran's I test positively confirmed clustering at both the district (0.199, p?.001) and village (0.256, p?.001) levels, whereas a Local Moran's I test further detected clustering in the central and terai regions, where dynamic geologic and geomorphic processes combined with human-environment interaction constitute major risk factors. A better understanding of multihazard mortality patterns across geographic landscapes and time has the potential to aid policy makers, planners, and local officers to more efficiently allocate scarce capital and human resources to reduce mortality. 相似文献
Several snake tissue samples and one set of snake eggs were collected and analyzed for 2,3,7,8-tetrachlorodibenzo--dioxin. The isomer-specific analysis was performed using fused silica GC combined with atmospheric pressure ionization MS. The results ranged from a low of 38 parts-per-trillion (ppt) to high levels over 500 ppt. 相似文献
ABSTRACT: We evaluated maps of runoff created by means of two automated procedures. We implemented each procedure using precipitation estimates of both 5-km and 10-km resolution from PRISM (Parameter-elevation Regressions on Independent Slopes Model). Our goal was to determine if using the 5-km PRISM estimates would improve map accuracy. Visual inspection showed good general agreement among our runoff maps, as well as between our maps and one produced using a manual method. A quantitative uncertainty analysis comparing runoff interpolated from our maps with gage data that had been withheld showed slightly smaller actual and percentage interpolation errors for the 5-km PRISM-based maps. Our analyses suggest a modest region-wide improvement in runoff map accuracy with the use of PRISM-based precipitation estimates of 5-km (compared to 10-km) resolution. 相似文献
Between 1978 and 1983, eggs from 15 species of Antarctic and Subantarctic seabirds were collected and analysed for organochlorine pesticides, PCBs, and mercury residues. The lowest levels of these chemicals were detected in the eggs of Adélie Penguins from Prydz Bay. Antarctica. On a wet weight basis, the mean concentrations in eggs of these penguins were 0.01 μg/g HCB, 0.005 μg/g DDE, less than 0.1 μg/g PCBs (1260) and 0.02 μg/g mercury. Such values indicate that the environmental levels of these contaminants in the biotypes of these species are extremely low, and present no significant threat.
The highest levels of contaminants were found in the eggs of species which breed in Antarctica and migrate to regions well north of the Antarctic Convergence in the non-breeding season. On a wet weight basis, Northern Giant-Petrel eggs contained 0.11 μg/g HCB, 0.95 μg/g DDE and 1.8 μg/g PCB (1260), and 1.8 μg/g mercury. There are indications that DDE levels are increasing for both Southern and Northern Giant-Petrels, and it is possible that reports of a decreasing number of breeding pairs of these species at several colonies are due to one or more of these contaminants reaching toxic levels.
Analysis of penguin tissues show that preen gland lipid is suitable for monitoring the body burden of organochlorine insecticides and PCBs in seabirds.
Variation in DDE and mercury residue levels for some of these species suggest that the biotypes in which they live are quite different, and that the Antarctic Convergence may have a major influence in protecting the Antarctic ecosystem from these pollutants. 相似文献
This article, a theoretical perspective based on a literature study, is a critical evaluation of SIA as part of the EIA process in South Africa against the background of international guidelines and best practices. It includes sections on the historical background of the development of SIA in South Africa, the legal status and requirements of SIA in the country, and a critical evaluation of SIA regulation in South Africa. The conclusion reached in the article is that the persistent problems of SIA practice, experienced in other parts of the world, are also evident in South Africa. Apart from institutional, financial and professional constraints, there are also serious problems associated with approach and methods. This conclusion confirms the findings of empirical studies that SIA in South Africa is neglected, that the practice of SIA in South Africa is not yet on a sound footing, and that it does not receive the professional attention it deserves in a country beset by enormous social challenges. To conclude the article recommendations are made to improve the level of SIA practice in South Africa, and the possible significance of this national case study for international practice is indicated. 相似文献
Conservation planning tends to focus on protecting species’ ranges or landscape connectivity but seldom both—particularly in the case of diverse taxonomic assemblages and multiple planning goals. Therefore, information on potential trade-offs between maintaining landscape connectivity and achieving other conservation objectives is lacking. We developed an optimization approach to prioritize the maximal protection of species’ ranges, ecosystem types, and forest carbon stocks, while also including habitat connectivity for range-shifting species and dispersal corridors to link protected area. We applied our approach to Sabah, Malaysia, where the state government mandated an increase in protected-area coverage of approximately 305,000 ha but did not specify where new protected areas should be. Compared with a conservation planning approach that did not incorporate the 2 connectivity features, our approach increased the protection of dispersal corridors and elevational connectivity by 13% and 21%, respectively. Coverage of vertebrate and plant species’ ranges and forest types were the same whether connectivity was included or excluded. Our approach protected 2% less forest carbon and 3% less butterfly range than when connectivity features were not included. Hence, the inclusion of connectivity into conservation planning can generate large increases in the protection of landscape connectivity with minimal loss of representation of other conservation targets. 相似文献