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71.
Plant species composition and species number were studied in two types of field margins: 31 arable field margins and 33 road verges. Both field margin types were adjacent to intensively managed grass or cereal fields. Effects of eight variables on field margin vegetation were studied. Despite having many plant species in common, composition and species number differed between the two field margin types, due to different ecological conditions and margin management. Arable field margins were composed of tall and/or nutrient demanding ubiquitous species and were characterised by species of later successional stages than those of road verges. The vegetation of road verges was lower and species numbers were higher than in arable field margins. The road verges contained several semi-natural meadow species that are declining in abundance. A CCA ordination of the field margins and the recorded variables showed that plant species composition was significantly affected by thickness of litter, slope, width, moisture level and type of crop in the adjacent field. Number of plant species was significantly higher in mown than unmown margins and generally higher in margins adjacent to fields with mainly grass production than in margins adjacent to fields with mainly cereal crops. In order to preserve botanical diversity in this agricultural landscape, the maintenance of regularly mown road verges should be prioritized. 相似文献
72.
Abstract: In a preliminary analysis of listing decisions under Canada's Species at Risk Act (SARA), Mooers et al. (2007) demonstrated an apparent bias against marine and northern species. As a follow‐up, we expanded the set of potential explanatory variables, including information on jurisdictional and administrative elements of the listing process, and considered an additional 16 species recommended for listing by SARA's scientific advisory committee as of 15 August 2006. Logistic model selection based on Akaike differences suggested that species were less likely to be listed if they were harvested or had commercial or subsistence harvesting as an explicitly identified threat; had Department of Fisheries and Oceans (DFO) as a responsible authority (RA); were located in Canada's north generally, and especially in Nunavut; or were found mostly or entirely within Canada. Subsequent model validation with an independent set of 50 species for which a listing decision was handed down in December 2007 showed an overall misclassification rate of <0.10, indicating reasonable predictive power. In light of these results, we recommend that RAs under SARA adopt a two‐track listing approach to address problems of delays arising from extended consultations and the inconsistent use by the RAs of socioeconomic analysis; consider revising SARA so that socioeconomic analysis occurs during decisions about protecting species and their habitats rather than at the listing stage; and maintain an integrated database with information on species’ biology, threats, and agency actions to enable future evaluation of SARA's impact. 相似文献
73.
Understanding how different audience groups perceive wildlife is crucial for the promotion of biodiversity conservation, especially given the key role of flagship species in conservation campaigns. Although the heterogeneity in preferences reinforces the need for campaigns tailored to specific target audiences, many conservation education and awareness campaigns still claim to target the “general public”. Audiences can be segmented according to social, economic, and cultural criteria across which species perceptions are known to vary. Different studies have investigated the preferences of different groups towards certain wildlife species, but these are largely confined to a single conservation stakeholder group, such as tourists, local communities, or potential donors in western countries. In this study, we seek to determine from a multi-stakeholder perspective, audience characteristics that influence perceptions towards wildlife at Valparai, a fragmented plateau in the Western Ghats region of the Western Ghats-Sri Lanka Hotspot. We found that stakeholder group membership was the most important characteristic followed by gender. While some characteristics had a wide-scale effect others were restricted to a few species. Our results emphasize the need to design conservation campaigns with specific audiences in mind, instead of the very often referred to “general public”. 相似文献
74.
David R. Breininger Mary Jo Barkaszi Rebecca B. Smith Donna M. Oddy Jane A. Provancha 《Environmental management》1998,22(2):315-321
/ We identified and ranked 108 resident and migratory wildlife taxa on John F. Kennedy Space Center (KSC) that were vulnerable to local, regional, or global extinction. We ranked taxa based on their vulnerability to extinction, their potential role for maintaining faunal integrity, and the relevance of KSC for maintaining their populations in the United States and Florida. Several taxa, not listed by agencies, were vulnerable to regional or global extinction. Many taxa not vulnerable to global extinction were vulnerable to local and regional extinction. Top predators were vulnerable to extinction because of small population size, isolation from other populations, and road mortality. Many taxa were dependent on habitat conditions at different geographic locations so that conservation required greater collaboration among land owners, managers, and researchers at local, regional, and global scales.KEY WORDS: Biological diversity; Endangered species; Conservation 相似文献
75.
Management of ecological reserve lands should rely on the best available science to achieve the goal of biodiversity conservation.
“Adaptive Resource Management” is the current template to ensure that management decisions are reasoned and that decisions
increase understanding of the system being managed. In systems with little human disturbance, certain management decisions
are clear; steps to protect native species usually include the removal of invasive species. In highly modified systems, however,
appropriate management steps to conserve biodiversity are not as readily evident. Managers must, more than ever, rely upon
the development and testing of hypotheses to make rational management decisions. We present a case study of modern reserve
management wherein beavers (Castor canadensis) were suspected of destroying habitat for endangered songbirds (least Bell’s vireo, Vireo bellii pusillus, and southwestern willow flycatcher, Empidonax traillii extimus) and for promoting the invasion of an exotic plant (tamarisk, Tamarix spp.) at an artificial reservoir in southern California. This case study documents the consequences of failing to follow
the process of Adaptive Resource Management. Managers made decisions that were unsupported by the scientific literature, and
actions taken were likely counterproductive. The opportunity to increase knowledge of the ecosystem was lost. Uninformed management
decisions, essentially “management by assertion,” undermine the long-term prospects for biodiversity conservation. 相似文献
76.
Gleason SM Faucette DT Toyofuku MM Torres CA Bagley CF 《Environmental management》2007,40(6):1016-1024
Acting under the auspices of the US Endangered Species Act, we quantified wind erosion and its effects on rare and common
plant species on a semi-arid military installation in Hawaii. Our goal was to develop management strategies, based on local
data, to aid the conservation of rare and common indigenous plants and their habitats. We collected windblown soil coming
off of roads and other disturbed soils to assess likely impacts to plants occurring at certain heights and distances from
disturbed surfaces. We then subjected plants in a glasshouse to windblown dust treatments, designed from our field data to
simulate erosion events, and evaluated the effect of these treatments on photosynthesis and survival. We also designed several
field experiments to examine the in-situ effects of windblown soil and soil substrate on germination, growth rate, and survival
of indigenous and nonindigenous plants. We conclude from these experiments that most direct effects of windblown soil to plants
can be effectively mitigated by locating roads and training areas at least 40 m from sensitive plant habitats and through
vegetation management to maintain at least 11% aerial cover on disturbed surfaces. Effects of soil type on germination, growth,
and survival was species-specific, emphasizing the importance of species trials prior to, or during, rehabilitation efforts. 相似文献
77.
Comparison of vegetation conditions along two backcountry trails in Mount Robson Provincial Park, British Columbia (Canada) 总被引:4,自引:0,他引:4
Vegetation conditions, i.e., plant cover, species richness, and the presence of exotic species, are compared along a high-use trail (Berg Lake Trail--BLT) and a low use trail (Mt. Fitzwilliam Trail--FWT) in Canada's Mt. Robson Provincial Park. We established 71 paired quadrats (1 m x 1 m), and assessed the amount of vegetation cover and species richness by four main lifeforms, i.e., woody species, herbaceous species, ferns, and moss, lichen and fungi. The following hypotheses were tested: (1) differences exist between control and trailside quadrats in vegetation cover, species richness and floristic diversity, and (2) differences exist between the high and low-use trails in the above-mentioned three parameters. Results show that for the majority of variables the differences between the control and trailside quadrats are statistically not significant. Variables showing significant differences are relative vegetation cover (for BLT only), exposed soil (BLT and FWT), herbaceous cover (FWT), moss, lichen and fungi cover (BLT), overall species richness (BLT), and herbaceous species richness (BLT). Ruderal and exotic species are present but only on trailside quadrats of the high-use trail. Results indicate that the Park administration's strategy to disperse use in the Mt. Robson Provincial Park should be examined critically, and some guidelines for acceptability of changes should be developed. 相似文献
78.
Uncertainty,complexity and controversy in dolphin threat management: A role for post-normal science?
Managing fishing threats to populations of endemic, threatened Hector’s and Māui dolphins around New Zealand is a complex and controversial issue, underpinned by uncertain scientific knowledge. As such, it can be argued that it falls into the realm of post-normal science, which advocates transparency about uncertainties and stakeholder peer review of knowledge feeding into decision-making. This paper focuses on selected examples of modelling and risk assessment research relating to Hector’s and Māui dolphin threat management. It explores how knowledge is developed, shared and utilised by decision-makers, finding that uncertain scientific knowledge may be shared in ways that make it appear more certain, with some of the subjectivities involved in knowledge production hidden from view. Interviews with stakeholders illustrate how some stakeholders are aware of the subjectivities involved when uncertain knowledge underpins decision-making, so a lack of transparency may be leading to erosion of social trust in decisions made. This in turn can lead to a lack of support for dolphin conservation measures from key stakeholders such as the commercial fishing industry. The paper concludes that while moves towards increasing transparency and stakeholder involvement are apparent, a deeper embrace of post-normal science approaches to knowledge production and dissemination would contribute to effective dolphin threat management in New Zealand. 相似文献
79.
Lee Hannah 《Environmental management》1986,10(5):611-621
Hawaii possesses abundant geothermal resources and rare native wildlife. Geothermal energy development has not posed a threat to native wildlife in the past, but development potential has recently reached a level at which concern for native wildlife is warranted.Potential geothermal resource areas in Hawaii intersect important native forest and endangered species habitat. The ability of existing laws to constrain development in these areas is in question. State and federal endangered species and environmental reporting laws have little ability to constrain geothermal development on private land. Hawaii's Land Use Law had been viewed by conservationists as protecting natural areas important to native wildlife, but recent decisions of the state Land Board sharply challenge this view.While this dispute was being resolved in the courts, the state legislature passed the Geothermal Subzone Act of 1983. Wildlife value was assessed in the geothermal subzone designation process mandated by this act, but the subzones designated primarily reflected inappropriate developer influence. All areas in which there was developer interest received subzone designation, and no area in which there was no developer interest was subzoned. This overriding emphasis on developer interest violated the intent of the sub-zone act, and trivialized the importance of other assessment criteria, among them native wildlife values. 相似文献
80.
Glen F. Cole 《Environmental management》1987,11(2):257-264
Human-influenced changes in the diversity and abundance of native wildlife in a southern boreal forest area, which became a national park in 1975, are used to develop working hypotheses for predicting and subsequently measuring the effects of disturbance or restoration programs on groups of interacting species. Changes from presettlement conditions began with early 1900 hunting, which eliminated woodland caribou (Rangifer tarandus) and elk (Cervus elaphus), and reduced moose (Alces alces) to the low numbers which still persist. Increases in white-tailed deer (Odocoileus virginianus), as these other cervid species became less abundant or absent, provided enough alternative food to sustain the system's carnivores until plant succession on previously burned or logged areas also caused deer to decline. With increased competition for reduced food, carnivore species also became less abundant or absent and overexploited some prey populations. The abilities of interacting species to maintain dynamically stable populations or persist varied with their different capacities to compensate for increased exploitation or competition. These relationships suggested a possible solution to the problem of predicting the stability of populations in disturbed systems. For the 1976–1985 period, a hypothesis that the increased protection of wildlife from exploitation in a national park would restore a more diverse, abundant, and productive fauna had to be rejected. 相似文献