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1.
  1. Freshwater communities are threatened by the conversion of natural landscapes for urban and agricultural purposes. Changes to land use may disrupt stream nutrient and geomorphological processes and reduce water quality, increase sedimentation, and decrease habitat heterogeneity eventually leading to species loss and decreases in ecosystem productivity. Endemic species are frequently at greater risk of habitat-mediated fragmentation and extirpation due to their constrained distributions.
  2. The Kanawha darter (Etheostoma kanawhae) is an understudied fish endemic to the New River Drainage in North Carolina and Virginia, USA. To investigate the potential effect(s) of land-use change on Kanawha darters, naïve occupancy was modelled using instream habitat characteristics and upstream forest cover.
  3. Generalized linear models revealed that instream habitat and forest cover are reliable predictors of Kanawha darter site occupancy. Specifically, models demonstrated that occupancy increased in reaches with reduced stream width, velocity, and bedrock substrate but higher concentrations of coarse woody material. Kanawha darter occupancy was also positively associated with the extent of forest cover in upstream catchments.
  4. Although Kanawha darters are not currently considered imperilled, most populations occurred in isolated reaches separated by large sections of unoccupied habitat. Continuing ex-urban development in riparian zones is likely to be the primary threat to Kanawha darters and other endemic species in this catchment. Resource managers and stakeholders should preserve forest cover in headwaters and occupied tributaries and protect or restore riparian zones along the main-stem South and North Forks of the New River to preserve high-quality habitat and enhance connectivity among isolated Kanawha darter populations.
  5. As human populations in montane regions continue to grow, there is a need to understand how land-use change affects endemic freshwater species. This study further supports the importance of retaining forest cover as an effective strategy for protecting and restoring populations of endemic fishes in high-gradient streams.
  相似文献   
2.
针对我国长江中下游地区因梅雨季节阴雨时间长、降水量大而集中常常引发涝灾和造成棉花渍害的现象,总结提出了一系列棉花防涝防渍及灾后田间管理技术措施与要求,以期为长江中下游地区棉农提供技术指导,促进当地棉花产业的发展和植棉效益的提高。  相似文献   
3.
Reservoirs are mostly managed at local scales as spatially independent units. A basin‐scale perspective may increase awareness at a broader scope and generate insight not evident at local scales. We examined the array of reservoir attributes and fisheries in the Mississippi Basin to identify management opportunities. The basin is the third largest in the world and includes over 1,700 reservoirs >100 ha, the most of any river basin. Our bird's‐eye view shows a piecemeal approach where reservoirs are mostly administered at the local level. Basin‐wide or catchment coordination to holistically address problems that recur across the basin is mostly lacking. A basin‐wide coordination arrangement could facilitate various facets of reservoir management. We reviewed governance arrangements in major river basins across the globe and concluded that the basin‐wide administrative layer we encourage for the Mississippi Basin may already exist in some basins but may not be directly applicable everywhere.  相似文献   
4.
[目的] 对河南省郑州市主城区城市发展与河网演变间的相互作用进行分析,为合理调节城市水资源提供科学依据。[方法] 以郑州市主城区为研究对象,基于1994,2002,2009和2019年遥感影像数据,计算河网特征指数并建立耦合协调模型,定量分析河网演变及其与城市发展间的相互作用关系。[结果] 城市发展与河网演变间的相互影响表现在城市发展对河网的破坏与促进作用和河网对城市发展的支撑与约束作用。城市发展导致河网密度降低,走向单一,结构简化,但河网是城市形态的骨架并提供物质基础,当河网承受能力趋于阈值时会反向约束城市发展,进而引起对河网的修复。郑州市主城区城市发展与河网耦合协调度变化可分为波动、磨合和稳发展3个阶段:初期城市的高强度发展使两者协调度迅速下降;中期开始注重河网的修护,人工水系的建设巩固了河网结构,期间受地形影响,城区主体避开西南丘陵地区向东部平原地区扩展;后期水系的治理与修复成效显著,协调度提升到初级协调等级并有逐步提升趋势。[结论] 人工水利措施的干预可缓解城市发展对河网的影响,但河网的修复成效落后于城市发展进程,仍需加强对河网的修复与保护。  相似文献   
5.
Atlantic salmon Salmo salar L. and brown trout Salmo trutta fario L. are species of high socio-economic and ecological value. Declining populations make them target species of fisheries management. This paper reviews the direct effects of deficient longitudinal connectivity, changes in discharge, high water temperatures, oxygen depletion, changes in water chemistry and increasing loads of fine sediment on the critical life stages of spawning, egg incubation and emergence. It further provides an overview about the basic autecological requirements of Atlantic salmon and brown trout and summarises important thresholds of physico-chemical tolerances. This collection of information provides important baselines for assessing historical, ongoing and new threats relevant for the management of both species in fresh waters. Critical early-life stages of both species are almost identical, creating synergies in conservation and restoration. Seaward-migrating forms are exposed to further stressors, but improving starting conditions can also greatly improve their resilience.  相似文献   
6.
针对农村坑塘"无人治、没钱治、无人管、散乱难治"等方面的难题,以乡村振兴战略为思想指导,结合河长制工作重点,根据农村坑塘高效治理工作对打造生态宜居环境、创建乡风文明、促进产业兴旺、实现农民富裕的重要性。在此基础上,以河南省睢县农村坑塘为例,以全面推行河湖长制促进乡村振兴为目标,把小微水体整治与乡村振兴等工作有机结合,进行水岸同治。按照远村塘、近村塘的分类,提出相应建设模式,并提出农村坑塘建设建议;另外,从"人治"和"法治"两个方面进行"人治巩固基础,法治加深层次"管护模式,为黄淮地区农村坑塘治理提供多种路径,助力乡村振兴。  相似文献   
7.
农田汇水河道水生植物原位净化工程处理效果分析   总被引:1,自引:1,他引:0  
为了研究水生植物原位净化工程处理效果,于2017年5—11月,在江苏省泗洪县四河乡的农田汇水河道,利用水葫芦和绿狐尾藻构建组合生态浮床,沿着水流方向设置4个水质采样点,每月监测水体基本理化指标,主要包括水温(T)、酸碱度(pH)、溶解氧(DO)、总氮(TN)、总磷(TP)、化学需氧量(COD_(Cr))、悬浮物(SS),分析河段水质沿程变化;在试验开始时、每次采收时监测单位面积植物生物量,干物质含量与氮磷含量,计算植物氮磷富集量。结果显示:植物种养后,沿程各采样点数据对比,水体pH值逐渐趋于中性;各采样时间数据对比,水体DO浓度呈升高趋势。在植物旺盛生长期(7—10月),组合生态浮床对河段水体TN、TP、COD和SS的沿程总消减率分别为50.41%~78.00%、44.62%~73.33%、46.15%~57.82%和33.33%~52.38%,其中最高值出现在8月。按照有效试验周期180 d(5—10月)计算,水葫芦的氮、磷去除量分别约为0.76 g·m~(-2)·d~(-1)和0.09 g·m~(-2)·d~(-1);绿狐尾藻的氮、磷去除量分别约为1.17 g·m~(-2)·d~(-1)和0.08 g·m~(-2)·d~(-1)。除了植物自身的吸收作用,根系微生物降解作用在污染物净化过程中也发挥了重要作用。在农田汇水河道原位净化工程中,水葫芦与绿狐尾藻组合生态浮床大幅消减水体氮磷浓度,有效降解有机物及拦截颗粒物,对于缓解下游水域富营养化问题具有积极的意义。  相似文献   
8.
  1. The Alaskan Matanuska‐Susitna Basin (MSB) provides habitat for all five Pacific salmon species, and their large seasonal spawning runs are important both ecologically and economically. However, the encroachment of human development through urbanization and extractive industries poses a serious risk to salmon habitat in the MSB.
  2. Using systematic conservation planning techniques, different methods of incorporating anthropogenic risks were assessed to determine how to conserve salmon habitat in the area cost‐effectively.
  3. The consequences of four distinct conservation scenarios were quantified: no consideration either of urbanization or extractive industries (‘Risk ignored’ scenario); accounting for the risk of urbanization, and avoiding conservation in all areas rich in fossil fuels (‘Urbanization accounted, all extraction avoided’ scenario); accounting for urbanization and oil and gas development, but avoiding conservation in coal‐rich areas (‘Urbanization accounted, coal areas avoided’ scenario); and accounting for all anthropogenic risks to habitat, and allowing conservation in oil, gas, or coal‐rich areas (‘All risks accounted’ scenario). To compare conservation success and resilience, the impacts of these risks were estimated using Monte Carlo simulations. The final cost of each solution was then divided by the number of conservation targets met to determine a return on investment.
  4. Results from scenarios that avoided all extractive activities, or only coal, suggest that conservation targets cannot be met simply by avoiding areas rich in fossil fuels, and these scenarios resulted in lower returns on investment than those in which risks from extraction were incorporated into the solution.
  5. By developing a method for setting priorities that are economically based, this study provides a method for local managers and conservation groups to identify conservation opportunities in MSB river basins.
  相似文献   
9.
  1. Marine protected areas (MPAs) and freshwater protected areas (FPAs), collectively aquatic protected areas (APAs), share many commonalities in their design, establishment, and management, suggesting great potential for sharing lessons learned. However, surprisingly little has been exchanged to date, and both realms of inquiry and practice have progressed mostly independent of each other.
  2. This paper builds on a session held at the 7th World Fisheries Congress in Busan, South Korea, in May 2016, which explored crossover lessons between marine and freshwater realms, and included case studies of four MPAs and five FPAs (or clusters of FPAs) from nine countries.
  3. This review uses the case studies to explore similarities, differences, and transferrable lessons between MPAs and FPAs under five themes: (1) ecological system; (2) establishment approaches; (3) effectiveness monitoring; (4) sustaining APAs; and (5) challenges and external threats.
  4. Ecological differences between marine and freshwater environments may necessitate different approaches for collecting species and habitat data to inform APA design, establishment and monitoring, but once collected, similar spatial ecological tools can be applied in both realms. In contrast, many similarities exist in the human dimension of both MPA and FPA establishment and management, highlighting clear opportunities for exchanging lessons related to stakeholder engagement and support, and for using similar socio‐economic and governance assessment methods to address data gaps in both realms.
  5. Regions that implement MPAs and FPAs could work together to address shared challenges, such as developing mechanisms for diversified and sustained funding, and employing integrated coastal/watershed management to address system‐level threats. Collaboration across realms could facilitate conservation of diadromous species in both marine and freshwater habitats.
  6. Continued exchange and increased collaboration would benefit both realms, and may be facilitated by defining shared terminology, holding cross‐disciplinary conferences or sessions, publishing inclusive papers, and proposing joint projects.
  相似文献   
10.
  1. The Pyrenean desman (Galemys pyrenaicus) is an endangered stream-dwelling insectivore endemic to the Iberian Peninsula and the north of the Pyrenees. It favours riffles over slow habitats such as runs or pools, yet it is still unclear whether habitat preference is based on prey availability or on other factors, such as mechanical constraints on its hunting habits.
  2. Desman diet and prey selection were analysed along the pristine Elama Stream and the slightly modified Leitzaran Stream in the Basque Country, Spain.
  3. In each stream the prey consumed were identified by metabarcoding 94 desman faeces, and prey availability characterized from 10 Surber samples taken in each habitat type (riffles, runs and pools). Invertebrates were sorted and identified, the biomass of each taxon was calculated, and their DNA was also extracted, amplified using PCR, and sequenced to build a reference database.
  4. Prey availability and diet varied between streams. Desmans positively selected shredders and invertebrates that live on the substrate, and selected against taxa that live in fine sediment, taxa with hard shells or those that are highly mobile. The diet of desmans was more selective in the Elama, the stream with better ecological status. Food availability did not differ among habitats, and therefore does not explain the preference of desmans for riffles; rather, mechanical constraints to deal with buoyancy and physical habitat heterogeneity were hypothesized to be the reason behind the habitat preference.
  5. The results suggest that promoting the formation of riffles in streams can improve the situation of some desman populations living in degraded habitats.
  相似文献   
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