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Jennifer F. Lind‐Riehl Audrey L. Mayer Adam M. Wellstead Oliver Gailing 《Conservation biology》2016,30(6):1288-1296
The U.S. Endangered Species Act (ESA) requires that the “best available scientific and commercial data” be used to protect imperiled species from extinction and preserve biodiversity. However, it does not provide specific guidance on how to apply this mandate. Scientific data can be uncertain and controversial, particularly regarding species delineation and hybridization issues. The U.S. Fish and Wildlife Service (FWS) had an evolving hybrid policy to guide protection decisions for individuals of hybrid origin. Currently, this policy is in limbo because it resulted in several controversial conservation decisions in the past. Biologists from FWS must interpret and apply the best available science to their recommendations and likely use considerable discretion in making recommendations for what species to list, how to define those species, and how to recover them. We used semistructured interviews to collect data on FWS biologists’ use of discretion to make recommendations for listed species with hybridization issues. These biologists had a large amount of discretion to determine the best available science and how to interpret it but generally deferred to the scientific consensus on the taxonomic status of an organism. Respondents viewed hybridization primarily as a problem in the context of the ESA, although biologists who had experience with hybridization issues were more likely to describe it in more nuanced terms. Many interviewees expressed a desire to continue the current case‐by‐case approach for handling hybridization issues, but some wanted more guidance on procedures (i.e., a “flexible” hybrid policy). Field‐level information can provide critical insight into which policies are working (or not working) and why. The FWS biologists’ we interviewed had a high level of discretion, which greatly influenced ESA implementation, particularly in the context of hybridization. 相似文献
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美国杏李园主要害虫与天敌类群间相关性分析 总被引:3,自引:0,他引:3
应用典范相关分析方法研究了美国杏李园丰要害虫与天敌间的相互关系,在未受干扰的自生园中.害虫亚系统与天敌亚系统间第一典范相关系数达到显著水平,天敌亚系统中瓢虫类、草蛉类与主要害虫蚜虫类,螨类的数量变动规律一致.而蜘蛛类与主要害虫的数最关系不密切,化防园内主要害虫与天敌间的典范相关系数均未达显著永平,这表明未受干扰的自生园和生防园内,害虫与天敌亚系统间存在着有效的数量反馈机制,天敌对害虫具有一定的自然抑制作用,而化防园内,害虫与天敌间的数量反馈机制因农药干扰而失调,生态平衡受破坏.自生园和生防园害虫与天敌主要类群间具正相关关系.害虫亚系统中,蚜虫类贡献最大,其次为山楂叶螨和李小食心虫:天敌亚系统中蜘蛛和瓢虫贡献最大,其次为瓢虫类和草蛉类,草蛉类贡献最小.说明蜘蛛类、瓢虫类与主要害虫的数量变动规律一致.而草蛉类与美国杏李园主要害虫的数量关系不密切. 相似文献
44.
美国洛杉矶空气管理经验分析 总被引:1,自引:0,他引:1
Daniel A. Mazmanian 《环境科学研究》2006,19(Z1):98-108
过去35年间,洛杉矶的经济和人口持续增长、城市扩张,但是洛杉矶的空气污染水平得到了下降,在达到加利福利亚州和《清洁空气法》所规定的大气质量总体目标方面,有了长足的进步.期间起到重大作用的因素包括:①固定污染源和移动污染源气体污染物排放的控制技术和企业实践的巨大进步.②联邦、州和地区的清洁空气政策的发展.③强有力的专门负责清洁空气政策的监督和执行行政机构的设立.④公众压力.⑤从信任政府运用命令与控制手段到利用激励手段和市场手段完成许多政策目标(包括空气污染控制)的变革.同时,该地区的人口还在持续增长,经济继续繁荣扩张,意味着将产生更多的空气污染物,尤其是来自移动污染源的污染物.另外,在公众不太支持加强政府力量或增加税收的形势下,要求政策制定者解决空气污染的问题或大幅度改变洛杉矶居民的生活方式. 相似文献
45.
David C. Pavlacky Jr. Christian A. Hagen Anne M. Bartuszevige Rich Iovanna Thomas Luke George David E. Naugle 《Conservation biology》2021,35(5):1564-1574
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
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Sandra L. Kirmeyer 《Journal of environmental psychology》1985,5(4):355-372
In the course of studying police dispatchers, five observers recorded the reactions of the employees (N = 37) to their presence throughout the work shift on three separate occasions. Four major research questions were considered: (a) extent of reaction, (b) relationship between interactions with the observer and changes in employees' work activities, (c) independence of verbal and nonverbal behavioral reactions, and (d) adaptation. On average, subjects or other employees initiated 10 interactions per hour with observers. These interactions were classified as subject-initiated (a) verbal, content related to research procedures; (b) verbal, non-research-related in content; (c) nonverbal only or (d) other employee-initiated verbal comment. Interaction with the observer was not related to the amount of work the subject did. Subjects' nonverbal and verbal responses were unrelated to each other as well as to the verbal responses of other employees. A priori expectations concerning adaptation to observation were tested with a 3 × 3 (segment by day) repeated-measures factorial design. Significant adaptation (P < 0·01) occurred within and between days in subjects' comments about research procedures and all comments from other employees. However, other behaviors showed with no evidence of adaptation or actual increases. The implications of these findings for measuring reactivity and deciding when adaptation has occurred are discussed. 相似文献
48.
Material Disposal Area G is the primary low-levelradioactive waste disposal site at Los Alamos NationalLaboratory, New Mexico, and is adjacent to Pueblo of SanIldefonso lands. Pueblo residents and Los Alamos scientists areconcerned about radiological doses resulting from uptake of AreaG radionuclides by mule deer (Odocoileus hemionus) andRocky Mountain elk (Cervus elaphus), then consumption ofdeer and elk meat by humans. Tissue samples were collected fromdeer and elk accidentally killed near Area G and were analyzedfor 3H, 90Sr, total U, 238Pu, 239, 240Pu,241Am, and 137Cs. These data were used to estimatehuman doses based on meat consumption of 23 kg y-1. Humandoses were also modeled using RESRAD, and dose rates to deer andelk were estimated with a screening model. Dose estimates tohumans from tissue consumption were 2.9 × 10-3 mSv y-1and 1.6 × 10-3 mSv y-1 from deer and elk, respectively,and RESRAD dose estimates were of the same order of magnitude. Estimated dose rates to deer and elk were 2.1 × 10-4 mGyd-1 and 4.7 × 10-4 mGy d-1, respectively. Allestimated doses were significantly less than established exposurelimits or guidelines. 相似文献
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