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11.
Experience with collaborative approaches to natural resource and environmental management has grown substantially over the past 20 years, and multi-interest, shared-resources initiatives have become prevalent in the United States and internationally. Although often viewed as “grass-roots” and locally initiated, governmental participants are crucial to the success of collaborative efforts, and important questions remain regarding their appropriate roles, including roles in partnership initiation. In the midst of growing governmental support for collaborative approaches in the mid-1990s, the primary natural resource and environmental management agency in Wisconsin (USA) attempted to generate a statewide system of self-sustaining, collaborative partnerships, organized around the state’s river basin boundaries. The agency expected the partnerships to enhance participation by stakeholders, leverage additional resources, and help move the agency toward more integrated and ecosystem-based resource management initiatives. Most of the basin partnerships did form and function, but ten years after this initiative, the agency has moved away from these partnerships and half have disbanded. Those that remain active have changed, but continue to work closely with agency staff. Those no longer functioning lacked clear focus, were dependent upon agency leadership, or could not overcome issues of scale. This article outlines the context for state support of collaborative initiatives and explores Wisconsin’s experience with basin partnerships by discussing their formation and reviewing governmental roles in partnerships’ emergence and change. Wisconsin’s experience suggests benefits from agency support and agency responsiveness to partnership opportunities, but cautions about expectations for initiating general-purpose partnerships.  相似文献   
12.
Nest defence behaviours, such as attacking predators and defending against predator attacks, expose birds to risk of injury and death. However, direct costs of such behaviours are poorly documented. To evaluate potential costs of nest defence behaviours in lesser snow geese (Chen caerulescens), we (1) estimated the proportion of interactions between arctic foxes (Alopex lagopus) and geese that resulted in physical contact and (2) examined how nest defence behaviours varied between male and female geese. We separated interactions into attacks initiated by foxes (attacks by foxes) and attacks initiated by geese (attacks by geese). Risks associated with attacks by geese were considerably lower than the risks associated with attacks by foxes; only 1 of 1,179 attacks by geese resulted in physical contact between foxes and geese, whereas 26 of 89 attacks by foxes involved such contact (two female geese were killed during these attacks). Attacks by geese were made almost exclusively by male geese (>97%), whereas female geese were involved in 75% of all attacks by foxes that resulted in physical contact with geese. There was, thus, a considerable difference in risks associated with male and female nest defence behaviours. We suggest that parental roles during nesting (i.e., females incubate and males guard) expose female geese to greater risk of injury and death. Male geese may, however, reduce the risk of injury or death to their mates with pre-emptive attacks on foraging foxes.  相似文献   
13.
Sexual selection theory predicts that a higher investment in offspring will turn females into the selective sex, while males will compete for accessing and courting them. However, there are exceptions to the rule. When males present a high reproductive investment, sex roles can reverse from typical patterns, turning males into the choosy sex, while females locate males and initiate courtship. In many spiders, males are smaller than females, wandering in search of sedentary females and maximizing the number of copulations. In the present study, we present findings on the sand-dwelling wolf spider, Allocosa brasiliensis, evidencing a reversal in typical courtship roles reported for the first time in spiders. Males were bigger than females. Females located males and initiated courtship. Copulation always occurred in male burrows and took place mainly in long burrows. Males donated their burrows to the females after copulation, closing the entrance before leaving with female cooperation from inside. Males would provide females with a secure place for ovipositing, being exposed to predation and diminishing their future mating possibilities until constructing a new burrow. The cost of vacating the burrow and losing the refuge in an unpredictable habitat, such as sand dunes, would explain the courtship roles reversal in this spider species. Results turn A. brasiliensis as a promising model for discussing the determinants of sex roles and the pressures that drive their evolution and maintenance. Electronic supplementary material The online version of this article (doi: ) contains supplementary material, which is available to authorized users.  相似文献   
14.
Much of our knowledge concerning the functions of territorial behaviour and how territories are defended by individuals comes from research on birds. The vast majority of this work has focused on temperate zone breeding territoriality in which territories are defended most obviously by males. Our understanding of the female role in territory defence is limited because they are less conspicuous and much harder to observe. We studied sex roles in territory maintenance and defence in a duetting, resident neotropical passerine, the white-bellied antbird (Myrmeciza longipes). This species maintains territories and pair bonds year round and both sexes sing and actively participate in territory defence. We performed a series of playback experiments throughout the dry (non-breeding) and wet (breeding) seasons. We exposed territorial pairs to three types of stimuli including: (1) single sex, male only songs, (2) single sex, female only songs, and (3) both sex songs/duets. Contrary to findings for most other tropical species, individuals defended their territories with equal levels of aggression regardless of stimuli. Furthermore, sex roles were very different, with males responding more aggressively than females to all stimuli throughout both seasons. Both males and females consistently responded more aggressively to territorial intrusions during the dry season than during the wet season, likely because food abundance is low in the dry season and territory value is high. Our analysis of duetting behaviour suggests that duets do not serve a significant role in mate guarding, or territory defence.  相似文献   
15.
以学生为中心的外语教学模式不再是以老师为中心开展教学活动.学习者的地位有所改变,然而与此同时,教师也被赋予了一个新的角色.本文引用语言学的理论对教师在这一全新的外语教学模式中的新角色作了阐述,探讨要适应这一角色所应具备的素质.  相似文献   
16.
熊娅 《环保科技》2014,20(4):42-45
通过对以往实证性研究文献的回溯,分析了影响中小企业作出积极主动型环境策略选择的某些管理层面的因素及其变化,并提出了今后我国在该领域的研究方向和建议。  相似文献   
17.
本文在分析地震危机事件特征以及管理人才在汶川地震的抗震救灾过程中的作用的基础上,总结出危机管理人才的素质及能力要求,并试探着提出培养和提高管理人才危机管理能力的途径.  相似文献   
18.
Understanding the process of the changing phytoplankton patterns can be particularly useful in water quality improvement and management decisions. However, it is generally not easy to illustrate the interactions between phytoplankton biomass and related environmental variables given their high spatial and temporal heterogeneity. To elucidate relationships between them, in a eutrophic shallow lake, Taihu Lake, relative long-term data set of biotic and abiotic parameters of water quality in the lake were conducted using multivariate statistical analysis within seasonal periodicity. The results indicate that water temperature and total phosphorus (TP) played governing roles in phytoplankton dynamics in most seasons (i.e. temperature in winter, spring and summer; TP in spring, summer and autumn); COD (chemical oxygen demand) and BOD (biological oxygen demand) presented significant positive relationships with phytoplankton biomass in spring, summer and autumn. However, a complex interplay was found between phytoplankton biomass and nitrogen considering significant positive relationships occurring between them in spring and autumn, and conversely negative ones in summer. As the predatory factor, zooplankton presented significant grazing-pressure on phytoplankton biomass during summer in view of negative relationship between them in the season. Significant feedback effects of phytoplankton development were identified in summer and autumn in view that significant relationships were obser,qed between phytoplankton biomass and pH, Trans (transparency of water) and DO. The results indicate that interactions between phyto:plankton biomass and related environmental variables are highly sensitive to seasonal periodicity, which improves understanding of different roles of biotic and abiotic variables upon phytoplankton variability, and hence, advances management methods for eutrophic lakes.  相似文献   
19.
三元模式是高等职业教育改革的一条重要途径。通过把三元模式与《会展服务与管理》课程相结合,具体细化三元模式的实践应用,深化《会展服务与管理》课程三元模式的内涵,重点对高等职业教育《会展服务与管理》课程三元模式的实现途径进行了探讨,包括整合教育资源、独创性的课程设计、采用“双导师”制授课、研究教学活动特点等方面。  相似文献   
20.
ABSTRACT Development of community water systems in rural areas through the Farmers Home Administration, U. S. D. A., has been marked since the initiation of the program in the early 1%O's. System development in Mississippi has been very rapid and now numbers the largest among the states excepting Texas. Concurrent with this growth, however, has been a concern for operational quality and efficiency as well as questions of community impacts. The paper is purposed with describing the results of research conducted relative to these areas and methods currently being employed or considered for dealing with problematic items.  相似文献   
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