首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   8篇
  免费   4篇
  1篇
农作物   1篇
水产渔业   7篇
畜牧兽医   3篇
  2023年   1篇
  2020年   1篇
  2019年   1篇
  2018年   1篇
  2016年   2篇
  2015年   2篇
  2014年   1篇
  2010年   2篇
  2002年   1篇
排序方式: 共有12条查询结果,搜索用时 15 毫秒
1.
Although considerable conservation resources have been committed to develop and use law enforcement monitoring and management tools such as SMART, measures of success are ill‐defined and, to date, few reports detail results post‐implementation. Here, we present 4 case studies from protected areas with Amur tigers (Panthera tigris altaica) in Russia, in which indicators of success were defined and evaluated at each. The ultimate goal was an increase in tiger numbers to 1 individual/100 km2 at each site. We predicted that improvements in law enforcement effectiveness would be followed by increases in prey numbers and, subsequently, tiger numbers. We used short‐term and long‐term indicators of success, including: (i) patrol team effort and effectiveness; (ii) catch per unit effort indicators (to measure reductions in threats); and (iii) changes in target species numbers. In addition to implementing a monitoring system, we focused on improving law enforcement management using an adaptive management process. Over 4 years, we noted clear increases in patrol effort and a partial reduction in threats. Although we did not detect clear trends in ungulate numbers, tiger populations remained stable or increased, suggesting that poaching of tigers may be more limiting than prey depletion. Increased effectiveness is needed before a clear reduction in threats can be noted, and more time is needed before detecting responses in target populations. Nonetheless, delineation of concrete goals and indicators of success provide a means of evaluating progress and weaknesses. Such monitoring should be a central component of law enforcement strategies for protected areas.  相似文献   
2.
Advocates, practitioners and policy-makers continue to use and advocate for marine protected areas (MPAs) to meet global ocean protection targets. Yet many of the worlds MPAs, and especially no-take MPAs, are plagued by poaching and ineffective governance. Using a global dataset on coral reefs as an example, we quantify the potential ecological gains of governing MPAs to increase compliance, which we call the ‘compliance gap’. Using ecological simulations based on model posteriors of joint Bayesian hierarchical models, we demonstrate how increased compliance in no-take MPAs could nearly double target fish biomass (91% increases in median fish biomass), and result in a 292% higher likelihood of encountering top predators. Achieving these gains and closing the compliance gap necessitates a substantial shift in approach and practice to go beyond optimizing enforcement, and towards governing for compliance. This will require engaging and integrating a broad suite of actors, principles, and practices across three key domains: (i)) harnessing social influence, (ii) integrating equity principles, and (iii) aligning incentives through market-based instruments. Empowering and shaping communication between actor groups (e.g., between fishers, practitioners, and policy-makers) using theoretically underpinned approaches from the behavioural sciences is one of the most essential, but often underserved aspects of governing MPAs. We therefore close by highlighting how this cross-cutting tool could be further integrated in governance to bolster high levels of compliance in MPAs.  相似文献   
3.
  • 1. The decline of large‐bodied predatory species in the oceans is a concern both from a sustainability perspective and because such species can have important ecological roles. Sharks are particularly vulnerable to fishing as their life histories are characterized by late age at maturity, large body size, and low fecundity.
  • 2. Substantial shark population declines have been documented for a number of coastal and pelagic systems, with high population abundance limited to a few remote locations. The relative abundance and composition of reef shark populations are assessed from 1975 to 2006 at a remote, largely uninhabited, group of atolls in the central Indian Ocean; the Chagos Archipelago.
  • 3. Number of sharks observed per scientific dive declined from a mean of 4.2 in the 1970s to 0.4 in 2006, representing a decline of over 90%. Silvertip sharks displayed an increase in abundance from 1996, whereas blacktip and whitetip reef sharks were rarely encountered in 2006.
  • 4. Poaching in the archipelago, is the most likely cause of these declines, highlighted by a number of illegal vessels containing large numbers of sharks arrested since 1996. The data highlight that shark populations, even in remote, otherwise pristine, marine areas, are vulnerable to distant fishing fleets, and a range of strategies will need to be used in concert for their conservation. Copyright © 2010 John Wiley & Sons, Ltd.
  相似文献   
4.
No‐take marine reserves are increasingly popular tools for conservation and fisheries management. While much attention has been paid to evaluating the effects of design aspects (size, location, etc.) in achieving reserve objectives, less emphasis has been placed on the role of stakeholder compliance. Therefore, the first aim of this study was to evaluate the state of compliance literature and examine the methods used to measure compliance in reserves. The state of compliance literature is limited, although publications with compliance information have increased sixfold in the last decade. However, most studies containing compliance information (63%) fail to provide quantitative estimates. Furthermore, most (95%) quantitative estimates of compliance were reported using a single method, which is problematic because each method has biases and limited applicability. Methods used to indicate compliance include (i) direct observation; (ii) indirect observation; (iii) law enforcement records; (iv) direct questioning; (v) expert opinion; and (vi) modelling. Our second aim was to empirically demonstrate the critical role of compliance in reserve outcomes by comparing a mixed‐effects model on compliance data synthesized from 63 marine reserves to that of a null model. The model of best fit demonstrated a negative relationship between non‐compliance and target species biomass response ratios. Thus, without incorporating any aspects of reserve design, compliance data predicted reserve response ratios of fish biomass. Accordingly, researchers should explore ways to better understand and measure non‐compliance. Therefore, future research should triangulate multiple sources of quantitative compliance data collected using standardized techniques and conduct baseline surveys before reserve implementation.  相似文献   
5.
6.
  • 1. Data are analysed from visual censuses of shallow‐water holothurians (sea cucumbers) in 72 shallow water transects 100 m×2 m within four atolls of Chagos. Mean holothurian abundance in Diego Garcia, where harvesting is absent, was 18.5 individuals/transect (all transects) and 55.4 individuals/transect (only those containing holothurians). In the three exploited atolls, mean abundance did not exceed 3.5 and 5.2 individuals/transect, respectively.
  • 2. Comparison with data collected during this study and an earlier investigation reveals a marked decline over four years in both mean and maximum density of commercially valuable Stichopus chloronotus and Holothuria atra in Salomon and Peros Banhos, both exploited atolls, and also for Holothuria nobilis in the latter.
  • 3. Holothurian counts were also made along an extensive transect (21 km×4 m) encircling Salomon atoll. Abundance showed highly significant negative correlation with fishing pressure, the latter estimated using an ordinal (0–3) scale (Rs=?0.605, P?0.01). Harvesting effects were not discernible using data from 200 m2 transects.
  • 4. While recent studies have shown Chagos is virtually pristine regarding contaminant levels, its holothurian resources are under increasing pressure. Results from this study, and examination of Sri Lanka's fishing activity in distant waters, point to heavy and illegal harvesting.
  • 5. Stronger measures are needed to control the illegal fishery, to prevent holothurian abundances falling to the non‐sustainable levels now prevalent across much of the Indo‐Pacific, and to ensure that Chagos remains a biodiversity hotspot and environment of international renown. Use of smaller surveillance vessels would facilitate this.Copyright © 2009 John Wiley & Sons, Ltd.
  相似文献   
7.
With increased poaching pressures, rhinoceroses have become a financial liability due to expensive anti-poaching security costs required to protect this species. Nonetheless, approximately one-third of South Africa’s rhinoceros population is protected on private lands. In a time when the future existence of rhinoceroses is uncertain, it is important to determine (a) the considerations included in private sector decisions to participate in rhinoceros conservation and (b) how increased conservation of rhinoceroses on private lands may be attained. We conducted semi-structured interviews with private wildlife ranchers and reserve managers in South Africa to answer these questions. Respondents cataloged financial (e.g., security costs, tourism revenues) and nonfinancial (e.g., psychological stresses, emotional attachment) factors that influence their decisions to keep rhinoceroses on their lands. Despite significant costs of rhinoceros ownership, rhinoceros owners were willing to engage in conservation efforts because of the nonfinancial benefits they derive from protecting rhinoceroses.  相似文献   
8.
South Africa currently loses over 1000 white rhinoceros (Ceratotherium simum) each year to poaching incidents, and numbers of severely injured victims found alive have increased dramatically. However, little is known about the antimicrobial treatment of wounds in rhinoceros. This study explores the applicability of enrofloxacin for rhinoceros through the use of pharmacokinetic‐pharmacodynamic modelling. The pharmacokinetics of enrofloxacin and its metabolite ciprofloxacin were evaluated in five white rhinoceros after intravenous (i.v.) and after successive i.v. and oral administration of 12.5 mg/kg enrofloxacin. After i.v. administration, the half‐life, area under the curve (AUCtot), clearance and the volume of distribution were 12.41 ± 2.62 hr, 64.5 ± 14.44 μg ml?1 hr?1, 0.19 ± 0.04 L h?1 kg?1, and 2.09 ± 0.48 L/kg, respectively. Ciprofloxacin reached 26.42 ± 0.05% of the enrofloxacin plasma concentration. After combined i.v. and oral enrofloxacin administration oral bioavailability was 33.30 ± 38.33%. After i.v. enrofloxacin administration, the efficacy marker AUC24: MIC exceeded the recommended ratio of 125 against bacteria with an MIC of 0.5 μg/mL. Subsequent intravenous and oral enrofloxacin administration resulted in a low Cmax: MIC ratio of 3.1. The results suggest that intravenous administration of injectable enrofloxacin could be a useful drug with bactericidal properties in rhinoceros. However, the maintenance of the drug plasma concentration at a bactericidal level through additional per os administration of 10% oral solution of enrofloxacin indicated for the use in chickens, turkeys and rabbits does not seem feasible.  相似文献   
9.
A perennial ryegrass (Lolium perenne L.)‐dominated sward on a well‐drained soil (Experiment 1) and a creeping bent (Agrostis stolonifera L.)‐dominated sward on a poorly drained soil (Experiment 2) were subjected to four treading treatments: control (C, no damage), light damage (L), moderate damage (M) or severe damage (S) to quantify the effects on herbage dry‐matter (DM) production and tiller density. In Experiment 1, treading damage was imposed in spring. In Experiment 2, one‐third of the site was damaged in autumn, one‐third in spring and one‐third in both spring and autumn. Both sites were rotationally grazed after treading treatments. Pre‐grazing herbage mass was measured eight times in Experiment 1 and seven times in Experiment 2 on each plot, and tiller density was assessed four times in each experiment. In Experiment 1, pre‐grazing herbage mass was reduced by 30% in S plots at the first harvest after damage, but cumulative pre‐grazing herbage DM production was not different between treatments (12·7 t DM ha?1). In Experiment 2, annual cumulative pre‐grazing herbage mass was reduced by between 14 and 49%, depending on intensity of treading damage event and season when damage occurred. Tiller density was not affected by treatment in either experiment. A perennial ryegrass‐dominated sward on a well‐drained soil was resilient to heavy treading damage. A creeping bent‐dominated sward on poorly drained soil requires a more careful grazing management approach to avoid major losses in cumulative pre‐grazing herbage mass production during wet weather grazing events.  相似文献   
10.
Illegal fishing is an acknowledged problem within no‐take areas (NTAs), which are frequently used as a marine conservation management tool. While gathering data on illegal fishing is difficult, it is necessary, as these data enable increased efficiency of compliance patrols, where resources are inherently limited. In particular, information about short‐term temporal variations in illegal fishing in NTAs is needed to guide management and compliance efforts. To address this knowledge gap, daily variations in illegal fishing effort were examined using surveillance cameras at two sites in New South Wales, Australia. Generalised linear modelling (GLM) identified that illegal fishing was significantly greater on non‐working days and during periods with no rain, light winds and slight seas. The GLM developed provided useful predictions of illegal activity in both the NTA used to build the model and in a second nearby NTA. The study demonstrated that illegal fishing was principally concentrated on days with good boating conditions and was greater at the study site closer to boat launching facilities. These insights will assist with future targeting of enforcement, community outreach and management efforts, which should focus on days and sites with an increased likelihood of illegal fishing.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号