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   355篇
  免费   150篇
  国内免费   1篇
环保管理   2篇
综合类   3篇
基础理论   497篇
评价与监测   2篇
灾害及防治   2篇
  2024年   22篇
  2023年   25篇
  2022年   28篇
  2021年   40篇
  2020年   35篇
  2019年   27篇
  2018年   33篇
  2017年   37篇
  2016年   37篇
  2015年   45篇
  2014年   32篇
  2013年   28篇
  2012年   26篇
  2011年   33篇
  2010年   31篇
  2009年   11篇
  2008年   11篇
  2006年   1篇
  2003年   1篇
  2002年   1篇
  2001年   1篇
  1985年   1篇
排序方式: 共有506条查询结果,搜索用时 0 毫秒
101.
江苏省12大湖泊水环境现状与污染控制建议   总被引:5,自引:0,他引:5  
江苏面积大于50km^2的12个湖泊的水质恶化、面积减少、富营养化、湖泊生态系统退化与湖泊受TP、TN的污染和围湖造田等有关。经济快速发展,第二产业结构偏重,排放污染的总量超过湖泊承载力,湖泊底泥释放N、P及入糊河流携带污染物为造成湖泊环境问题的根本原因。建议调整产业结构,执行严格的排放标准,围绕重点区域、重点行业、重点企业和重点污染源治理,由控制COD为主转为控制COD和N、P并重,引水调控水质,建立湖泊资源数据库和生态系统信息网络,开展湖泊污染物来源分析和富营养化机理研究,开展跨界区域统筹对湖泊综合治理。  相似文献   
102.
    
Climate refugia, areas where climate is expected to remain relatively stable, can offer a near-term safe haven for species sensitive to warming temperatures and drought. Understanding the influence of temperature, moisture, and disturbance on sensitive species is critical during this time of rapid climate change. Coastal habitats can serve as important refugia. Many of these areas consist of working forestlands, and there is a growing recognition that conservation efforts worldwide must consider the habitat value of working lands, in addition to protected areas, to effectively manage large landscapes that support biodiversity. The sensitivity of forest bats to climate and habitat disturbance makes them a useful indicator taxon. We tested how microclimate and forest management influence habitat use for 13 species of insectivorous bats in a large climate refugium in a global biodiversity hotspot. We examined whether bat activity during the summer dry season is greater in forests where coastal fog provides moisture and more stable temperatures across both protected mature stands and those regularly logged. Acoustic monitoring was conducted at a landscape scale with 20 study sites, and generalized linear mixed models were used to examine the influence of habitat variables. Six species were positively associated with warmer nighttime temperature, and 5 species had a negative relationship with humidity or a positive relationship with climatic moisture deficit. Our results suggest that these mammals may have greater climate adaptive capacity than expected, and, for now, that habitat use may be more related to optimal foraging conditions than to avoidance of warming temperatures and drought. We also determined that 12 of the 13 regionally present bat species were regularly detected in commercial timberland stands. Because forest bats are highly mobile, forage over long distances, and frequently change roosts, the stewardship of working forests must be addressed to protect these species.  相似文献   
103.
    
Amid a global infrastructure boom, there is increasing recognition of the ecological impacts of the extraction and consumption of construction minerals, mainly processed as concrete, including significant and expanding threats to global biodiversity. We investigated how high-level national and international biodiversity conservation policies address mining threats, with a special focus on construction minerals. We conducted a review and quantified the degree to which threats from mining these minerals are addressed in biodiversity goals and targets under the 2011–2020 and post-2020 biodiversity strategies, national biodiversity strategies and action plans, and the assessments of the Intergovernmental Science–Policy Platform on Biodiversity and Ecosystem Services. Mining appeared rarely in national targets but more frequently in national strategies. Yet, in most countries, it was superficially addressed. Coverage of aggregates mining was greater than coverage of limestone mining. We outline 8 key components, tailored for a wide range of actors, to effectively mainstream biodiversity conservation into the extractive, infrastructure, and construction sectors. Actions include improving reporting and monitoring systems, enhancing the evidence base around mining impacts on biodiversity, and modifying the behavior of financial agents and businesses. Implementing these measures could pave the way for a more sustainable approach to construction mineral use and safeguard biodiversity.  相似文献   
104.
    
Experts can provide valuable information to fill knowledge gaps in published research on management effectiveness, particularly for threatened ecosystems, for which there is often limited evidence and the need for prompt intervention to ensure their persistence. One such ecosystem, alpine peatland, is threatened by climate change and other pressures, provides vital ecosystem services, and supports unique biodiversity. In a workshop, we gathered and synthesized into an accessible format information from experts on interventions used, threat context, and intervention effectiveness for Australian alpine peatland and used this knowledge to evaluate local relevance of the global literature for this threatened ecosystem. Experts identified 15 interventions used to conserve Australian peatlands, most of which enhanced or restored peatland condition and effectively addressed diverse threats. Experts’ perspectives and global studies were strongly aligned, suggesting that research on peatland management may be broadly relevant across contexts, despite the distinct characteristics of Australian systems. Our workshop-based expert elicitation approach provided insights into current management practices unavailable in the literature.  相似文献   
105.
Abstract: Rare or narrowly distributed species may be threatened by stressors to which they have never been exposed or for which data are very limited. In such cases the species response cannot be predicted on the basis of directly measured data, but may be inferred from the response of one or more appropriate surrogate species. Here, I propose a practical way to use the stressor response of one or more surrogate species to develop a working hypothesis or model of the stressor response of the target species. The process has 4 steps: (1) identify one or more candidate surrogate species, (2) model the relationship between the stressor and the response variable of interest for the surrogate species, (3) adapt the stressor–response relationship from the surrogate species to a model for the target species, possibly using Bayesian methods, and (4) incorporate additional data as they become available and adjust the response model of the target species appropriately. I applied the approach to an endangered fish species, the amber darter (Percina antesella), which is potentially threatened by urbanization. I used a Bayesian approach to combine data from a surrogate species (the bronze darter[Percina palmaris]) with available data for the amber darter to produce a model of expected amber darter response. Although this approach requires difficult decisions on the part of the manager, especially in the selection of surrogate species, its value lies in the fact that all assumptions are clearly stated in the form of hypotheses, which may be scrutinized and tested. It therefore provides a rational basis for instituting management policy even in the face of considerable uncertainty.  相似文献   
106.
    
Understanding spatial and temporal variability in the distribution of species is fundamental to the conservation of marine and terrestrial ecosystems. To support strategic decision making aimed at sustainable management of the oceans, such as the establishment of protected areas for marine wildlife, we identified areas predicted to support multispecies seabird aggregations in the Timor Sea. We developed species distribution models for 21 seabird species based on at‐sea survey observations from 2000–2013 and oceanographic variables (e.g., bathymetry). We applied 4 statistical modeling techniques and combined the results into an ensemble model with robust performance. The ensemble model predicted the probability of seabird occurrence in areas where few or no surveys had been conducted and demonstrated 3 areas of high seabird richness that varied little between seasons. These were located within 150 km of Adele Island, Ashmore Reef, and the Lacepede Islands, 3 of the largest aggregations of breeding seabirds in Australia. Although these breeding islands were foci for high species richness, model performance was greatest for 3 nonbreeding migratory species that would have been overlooked had regional monitoring been restricted to islands. Our results indicate many seabird hotspots in the Timor Sea occur outside existing reserves (e.g., Ashmore Reef Marine Reserve), where shipping, fisheries, and offshore development likely pose a threat to resident and migratory populations. Our results highlight the need to expand marine spatial planning efforts to ensure biodiversity assets are appropriately represented in marine reserves. Correspondingly, our results support the designation of at least 4 new important bird areas, for example, surrounding Adele Island and Ashmore Reef. Pronostico de la Distribución Espacial de una Comunidad de Aves Marinas para Identificar Áreas Prioritarias de Conservación en el Mar de Timor  相似文献   
107.
Abstract: Some conservationists argue for a focused effort to protect the most critically endangered species, and others suggest a large‐scale endeavor to safeguard common species across large areas. Similar arguments are applicable to the distribution of scientific effort among species. Should conservation scientists focus research efforts on threatened species, common species, or do all species deserve equal attention? We assessed the scientific equity among 1909 mammals, birds, reptiles, and amphibians of southern Africa by relating the number of papers written about each species to their status on the International Union for Conservation of Nature Red List. Threatened large mammals and reptiles had more papers written about them than their nonthreatened counterparts, whereas threatened small mammals and amphibians received less attention than nonthreatened species. Threatened birds received an intermediate amount of attention in the scientific literature. Thus, threat status appears to drive scientific effort among some animal groups, whereas other factors (e.g., pest management and commercial interest) appear to dictate scientific investment in particular species of other groups. Furthermore, the scientific investment per species differed greatly between groups—the mean number of papers per threatened large mammal eclipsed that of threatened reptiles, birds, small mammals, and amphibians by 2.6‐, 15‐, 216‐, and more than 500‐fold, respectively. Thus, in the eyes of science, all species are not created equal. A few species commanded a great proportion of scientific attention, whereas for many species information that might inform conservation is virtually nonexistent.  相似文献   
108.
The effects of chronic exposure to increasing levels of human‐induced underwater noise on marine animal populations reliant on sound for communication are poorly understood. We sought to further develop methods of quantifying the effects of communication masking associated with human‐induced sound on contact‐calling North Atlantic right whales (Eubalaena glacialis) in an ecologically relevant area (~10,000 km2) and time period (peak feeding time). We used an array of temporary, bottom‐mounted, autonomous acoustic recorders in the Stellwagen Bank National Marine Sanctuary to monitor ambient noise levels, measure levels of sound associated with vessels, and detect and locate calling whales. We related wind speed, as recorded by regional oceanographic buoys, to ambient noise levels. We used vessel‐tracking data from the Automatic Identification System to quantify acoustic signatures of large commercial vessels. On the basis of these integrated sound fields, median signal excess (the difference between the signal‐to‐noise ratio and the assumed recognition differential) for contact‐calling right whales was negative (?1 dB) under current ambient noise levels and was further reduced (?2 dB) by the addition of noise from ships. Compared with potential communication space available under historically lower noise conditions, calling right whales may have lost, on average, 63–67% of their communication space. One or more of the 89 calling whales in the study area was exposed to noise levels ≥120 dB re 1 μPa by ships for 20% of the month, and a maximum of 11 whales were exposed to noise at or above this level during a single 10‐min period. These results highlight the limitations of exposure‐threshold (i.e., dose‐response) metrics for assessing chronic anthropogenic noise effects on communication opportunities. Our methods can be used to integrate chronic and wide‐ranging noise effects in emerging ocean‐planning forums that seek to improve management of cumulative effects of noise on marine species and their habitats. Cuantificación de la Pérdida de Espacio de Comunicación Acústica para Ballenas Francas Dentro y Alrededor de un Santuario Marino Nacional en E. U. A.  相似文献   
109.
Abstract: The Mediterranean Basin is a global hotspot of biodiversity. Hotspots are said to be experiencing a major loss of habitat, but an added risk could be the decline of some species having a special role in ecological relationships of the system. We reviewed the role of European rabbits (Oryctolagus cuniculus) as a keystone species in the Iberian Peninsula portion of the Mediterranean hotspot. Rabbits conspicuously alter plant species composition and vegetation structure through grazing and seed dispersal, which creates open areas and preserves plant species diversity. Moreover, rabbit latrines have a demonstrable effect on soil fertility and plant growth and provide new feeding resources for many invertebrate species. Rabbit burrows provide nest sites and shelter for vertebrates and invertebrates. In addition, rabbits serve as prey for a number of predators, including the critically endangered Iberian lynx (Lynx pardinus) and Spanish Imperial Eagle (Aquila adalberti). Thus, the Mediterranean ecosystem of the Iberian Peninsula should be termed “the rabbit's ecosystem.” To our knowledge, this is the first empirical support for existence of a multifunctional keystone species in a global hotspot of biodiversity. Rabbit populations have declined drastically on the Iberian Peninsula, with potential cascading effects and serious ecological and economic consequences. From this perspective, rabbit recovery is one of the biggest challenges for conservation of the Mediterranean Basin hotspot.  相似文献   
110.
Ecosystem function and resilience are compromised when habitats become fragmented due to land‐use change. This has led to national and international conservation strategies aimed at restoring habitat extent and improving functional connectivity (i.e., maintaining dispersal processes). However, biodiversity responses to landscape‐scale habitat creation and the relative importance of spatial and temporal scales are poorly understood, and there is disagreement over which conservation strategies should be prioritized. We used 160 years of historic post‐agricultural woodland creation as a natural experiment to evaluate biodiversity responses to habitat creation in a landscape context. Birds were surveyed in 101 secondary, broadleaf woodlands aged 10–160 years with ≥80% canopy cover and in landscapes with 0‐17% broadleaf woodland cover within 3000 m. We used piecewise structural equation modeling to examine the direct and indirect relationships between bird abundance and diversity, ecological continuity, patch characteristics, and landscape structure and quantified the relative conservation value of local and landscape scales for bird communities. Ecological continuity indirectly affected overall bird abundance and species richness through its effects on stand structure, but had a weaker influence (effect size near 0) on the abundance and diversity of species most closely associated with woodland habitats. This was probably because woodlands were rapidly colonized by woodland generalists in ≤10 years (minimum patch age) but were on average too young (median 50 years) to be colonized by woodland specialists. Local patch characteristics were relatively more important than landscape characteristics for bird communities. Based on our results, biodiversity responses to habitat creation depended on local‐ and landscape‐scale factors that interacted across time and space. We suggest that there is a need for further studies that focus on habitat creation in a landscape context and that knowledge gained from studies of habitat fragmentation and loss should be used to inform habitat creation with caution because the outcomes are not necessarily reciprocal.  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