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1.
Bianca de F. Terra Robert M. Hughes Francisco G. Araújo 《Ecology of Freshwater Fish》2016,25(4):527-544
Streams are under environmental pressures acting at different scales that influence the ecological organisation of their fish assemblages. However, the relative influence of the different scale‐related variables on assemblage composition and function is poorly understood. We evaluated the importance of local‐ and catchment‐scale environmental variables, as well as the spatial structure of the sampling sites, in shaping fish assemblages in Atlantic Forest streams. Local‐scale variables were those measured at the sampling sites, describing the local habitat conditions (e.g. depth, substrate type, altitude). Catchment‐scale variables were those integrating the upstream landscape of the sampling sites (e.g. catchment land use). Spatial distances were calculated from watercourse distance using principal coordinates of neighbour matrices. Altogether, 28 local and seven catchment variables were initially subjected to two processes of eliminating co‐linearity. Redundancy analysis was applied to the three matrices (spatial, local and catchment) to quantify the variance in the structure of the fish assemblages explained by each matrix. Local variables explained more variability in both taxonomic and functional assemblage structure, than catchment and spatial variables. Local variables also changed along the longitudinal gradient, which consequently influenced fish assemblage structure. This pattern was also influenced by anthropogenic alteration and non‐native species, which were more abundant in downstream sites. These results highlight the need to assess Atlantic Forest streams under different environmental scales, especially through the use of quantitative local‐scale metrics, and to consider the effects of longitudinal patterns in structuring fish assemblages when developing and implementing monitoring programmes, impact studies and conservation plans. 相似文献
2.
Anderson Ferreira Felipe R. de Paula Silvio F. de Barros Ferraz Pedro Gerhard Elaine A. L. Kashiwaqui José E. P. Cyrino Luiz A. Martinelli 《Ecology of Freshwater Fish》2012,21(1):12-22
Abstract – Aquatic ecosystems are influenced by the surrounding terrestrial environment. This work studied the influence of vegetation of riparian zones on the feeding patterns of two nektonic characids, Astyanax paranae and Bryconamericus iheringii, in a basin surrounded by an agricultural area. Nine streams within the Corumbataí River basin (São Paulo State, Brazil) with varying proportions of adjacent riparian forest (RF) and pastures were set apart in three arbitrary categories: Riparian Forest (>90% RF), Mixed Coverage (banks covered by 30–60% RF; MC) and Pasture (<29% RF, PA); resident characids were sampled in the dry and rainy seasons and evaluated in regard to composition of diets. Astyanax paranae fed on allochthonous food sources in RF and MC, and on autochthonous food sources on PA streams; B. iheringii fed on autochthonous food sources in RF streams and in mixed resources (detritus and sediment) in PA streams. Selection of food source was related to, and altered by, stream channel structure and composition of substratum. Preservation and restoration of native riparian vegetation is key to preservation of resident characids in small streams of this river basin. 相似文献
3.
Robin Abell Kari Vigerstol Jonathan Higgins Shiteng Kang Nathan Karres Bernhard Lehner Aparna Sridhar Emily Chapin 《水产资源保护:海洋与淡水生态系统》2019,29(7):1022-1038
- Water insecurity is a defining feature of the Anthropocene, with degraded water quality and unreliable flows putting the well‐being of upstream and downstream communities, both human and aquatic, at risk. Within this context, the protection of drinking water at its source – ‘source water protection’ – is growing as a complementary water security solution to conventional built infrastructure, particularly but not only to address non‐point source pollution.
- An assessment of the likely source catchments of 4000 cities, supplying water to as many as 1.7 billion city dwellers, found that 85% of the total area of the catchments overlaps with freshwater ecoregions of high biodiversity value. Source water protection could contribute to conserving important freshwater biodiversity elements in these catchments, through activities such as land protection, restoration, and agricultural and ranching best‐management practices.
- Empirical evidence supporting the benefits of these types of activities to freshwater species and ecosystems is sparse, especially when considered at the scales required to achieve meaningful conservation objectives. This article explores the potential of source water protection to deliver freshwater conservation benefits, and solutions are proposed to address the challenges related to evidence gaps, trade‐offs, and financing.
- The broader opportunity for leveraging water security investments for biodiversity conservation, and the overall efficiencies that may accrue from optimizing for multiple benefits simultaneously, are discussed in the context of global frameworks such as the Sustainable Development Goals.
4.
- Declines in populations of stone crayfish (Austropotamobius torrentium) have recently been reported throughout many parts of their range, including southern Germany. To assess the rate of decline and the probable causes, a crayfish survey was conducted in the River Argen catchment, where the species was known to be widely distributed and abundant.
- Using mixed‐effects regression analysis, the presence or absence of the species was subsequently correlated with riparian land‐use and habitat characteristics. To elucidate the potential role of crayfish plague in stone crayfish decline, the crayfish plague‐carrier status of newly discovered alien signal crayfish (Pacifastacus leniusculus) was evaluated using real‐time polymerase chain reaction (PCR).
- Twenty‐five of the 98 surveyed sites were colonized by stone crayfish, including only 12 of 25 sites with a previous record. The probability of stone crayfish presence was positively correlated with overhanging bank structures and the proportion of broad‐leafed woods in riparian buffers. In contrast, high proportions of intensive grassland had a distinct negative effect on the probability of stone crayfish presence, and cropland also tended to decrease the probability of stone crayfish presence. Both land‐use forms have significantly increased in the study area within the last decade, signifying an intensification of riparian land‐use.
- Plague‐carrying signal crayfish were present at two headwater sites. Crayfish plague transmission from highly resistant signal crayfish to highly susceptible stone crayfish has most likely contributed to the decline in stone crayfish, and crayfish plague outbreaks may account for up to 67% of the observed stone crayfish disappearances.
- The present study confirms a marked decline in stone crayfish populations, which is probably driven by the persistent spread of invasive alien species and intensified riparian land‐use. Therefore, conservation efforts for stone crayfish should incorporate strategies to prevent and control the spread of invasive, plague‐carrying crayfish, and to mitigate pressures from land use.
5.
K. J. Anlauf D. W. Jensen K. M. Burnett E. A. Steel K. Christiansen J. C. Firman B. E. Feist D. P. Larsen 《水产资源保护:海洋与淡水生态系统》2011,21(7):704-714
- The distribution and composition of in‐stream habitats are reflections of landscape scale geomorphic and climatic controls. Correspondingly, Pacific salmon (Oncorhynchus spp.) are largely adapted to and constrained by the quality and complexity of those in‐stream habitat conditions. The degree to which lands have been fragmented and managed can disrupt these patterns and affect overall habitat availability and quality.
- Eleven in‐stream habitat features were modelled as a function of landscape composition. In total, 121 stream reaches within coastal catchments of Oregon were modelled. For each habitat feature, three linear regression models were applied in sequence; final models were composed of the immutable and management‐influenced landscape predictors that best described the variability in stream habitat.
- Immutable landscape predictors considered proxies for stream power described the majority of the variability seen in stream habitat features. Management‐influenced landscape predictors, describing the additional human impacts beyond that which was inherently entwined with the immutable predictors, explained a sizeable proportion of variability. The largest response was seen in wood volume and pool frequency.
- By using a sequential linear regression analysis, management‐influenced factors could be segregated from natural gradients to identify those stream habitat features that may be more sensitive to land‐use pressures. These results contribute to the progressing notion that the conservation of freshwater resources is best accomplished by investigating and managing stream systems from a landscape perspective. Copyright © 2011 John Wiley & Sons, Ltd.
6.
为探讨济南市泉域范围的水源涵养量,利用Arcgis软件划定泉域范围,通过解译2000年、2005年、2010年、2015年和2020年的Landsat遥感影像数据,获取范围内土地利用类型;基于Invest模型并结合气象、土壤、地形等数据估算泉域水源涵养量,分析了近20年来泉域水源涵养量和涵养能力的时空变化及影响因素。结果表明,与2000年相比,泉域内土地利用类型变化较大,其中耕地面积变化最大,减少了470.1 km2;城乡居民点和工矿用地增长较快,增幅为9.1%;林地草地面积也呈增长态势,增幅为4.1%,面积占比达到了32.3%。泉域水源涵养量为157.9～238.3 mm,均值为188.8 mm,受降水影响较大;泉域水源涵养率为23.5%～25.9%,平均为24.2%,水源涵养能力较低。时间上,多年水源涵养率基本保持稳定;空间上,南部山区水源涵养能力较之前有所提升,中部受城市化影响而下降显著。各土地利用类型水源涵养量从大到小依次为：林地>草地>耕地>未利用土地>城乡居民点和工矿用地>水域和湿地,水源涵养率分别为49.15%、30.32%、20.09%、17.69%、8.62%和8.31%。区域内水源涵养功能区以一般重要区为主,面积占比40%,极重要区内林地占比为94.62%。植被类型和气象因素是影响区域水源涵养的主要因素,应结合土壤类型适当调整植被配置。 相似文献
7.
Joshuah S. Perkin Shannon P. Murphy Christopher M. Murray W. Keith Gibbs Amy E. Gebhard 《水产资源保护:海洋与淡水生态系统》2019,29(4):623-638
- Stream fish diversity is threatened by anthropogenic environmental alterations to landscapes, and successful conservation requires knowledge of the processes that degrade diversity. A primary step in identifying diversity losses is the comparison between historical and contemporary states of landscapes and fish assemblages, but uncertainty remains regarding the appropriate spatial scales of investigation.
- Historical data collected in 1976 were paired with two years of contemporary replication (2015, 2016) to assess fish diversity change at 10 sites in Blackburn Fork, TN, USA. Analyses focused on a nested hierarchy of spatial scales, including sampling sites (fine scale), nested within stream orders (intermediate scale), nested within the entire catchment (broad scale). Diversity change between 1976 and 2015–16 was assessed using traditional diversity metrics (site scale) and rarefaction (stream‐order scale), whereas spatial variation in contemporary diversity (2015–16) was assessed with nonmetric multidimensional scaling (catchment scale).
- At the site scale, locations on the east side of Blackburn Fork and in close proximity to developed land experienced diversity loss. At the stream‐order scale, the effective number of species declined in first‐order streams where land development was concentrated, but no consistent species losses occurred in other stream orders. At the catchment scale, assemblages responded significantly to stream size but not land use, perhaps because diversity was already homogenized by 2015–16. Mapping 40 years of land‐use change across the catchment underscored a pattern of spatial alignment between developed lands and stream fish diversity loss.
- This study highlights the benefits of considering multiple spatial scales when assessing historical change in stream fish assemblages, and highlights stronger inference derived from historical comparisons relative to contemporary space‐for‐time substitutions. This framework combines recent analytical advances in rarefaction with a riverscape perspective, and can be applied to conserve streams, and their biota, in riverscapes around the world.
8.
- Conserving fluxes of terrestrial invertebrates to streams, which supply about half of the diet of stream fish, is an important goal for aquatic conservation. Riparian land uses such as forestry and grazing could have strong indirect effects on fish, by reducing these prey inputs.
- A large‐scale replicated field experiment was conducted in four western US rangeland catchments to test the effects of three levels of cattle grazing in riparian pastures on vegetation, fluxes of invertebrates, trout diets, and trout abundance and biomass. The treatments mimicked common grazing systems.
- The grazing treatments reduced riparian vegetation biomass to levels as low as or lower than rotational grazing systems. The most intense treatment also removed two‐thirds of riparian shrubs, thereby reducing overhead cover.
- All grazing treatments reduced the inputs of terrestrial and adult aquatic insects to streams, compared with controls, but only reductions caused by the most intense treatment were statistically significant, owing to the high levels of natural variation among control sites. Significant reductions of invertebrate inputs by this treatment during key seasons confirmed that riparian shrubs are an important component in the supply of invertebrates to streams.
- All treatments reduced the levels of terrestrial invertebrate prey found in trout diets, by half or more at the end of the experiment. Some reductions appeared to be compensated for by greater foraging of trout on larvae and adults of aquatic invertebrates.
- Trout did not respond to reduced prey by adjusting their density or biomass, probably because they were in good body condition, prey inputs were the highest yet recorded to rangeland streams, and trout foraged selectively to buffer the loss.
- Conserving fluxes of terrestrial prey to trout in rangeland streams will require the careful management of cattle grazing, especially to sustain riparian shrubs that are likely to serve as sources and vectors for invertebrate inputs to streams.
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10.
- The influence of anthropogenic habitat loss on animal distribution and core habitat use can be particularly strong in animals with narrow habitat selectivity, such as the Indo‐Pacific humpback dolphin (Sousa chinensis), a delphinid species that specifically inhabits coastal and estuarine waters.
- This study measured the extent of habitat loss in the waters around Xiamen City, China, where intense environmental changes and coast utilization have occurred in the past 40 years. The extent of occurrence and the core habitat of the humpback dolphin were measured based on sighting records from censuses conducted in different years.
- A Landsat image series revealed a permanent 119.95 km2 loss of coastal waters to land reclamation, coastal modification and harbour construction from 1973 to 2013. The distribution of the humpback dolphin showed a significant shift from inshore to offshore waters and away from artificial shorelines. Though the extent of occurrence appears to change minimally, a significant shift in the core habitat from the original coastal habitats into mid‐channel waters was observed in the eastern Xiamen Bay.
- These results imply multiple consequences of anthropogenic coastal alterations for the humpback dolphin: the elimination of vital habitats, changes in habitat use preferences, and the partitioning of the social structure of the population.
- The need to adjust current protected area designations along with adequate measures to restore habitat quality and population connectivity, both locally and regionally, are considered.
11.
黎河是引滦入津工程的唯一通道,本文以遵化市黎河为研究对象,选取了12个具有代表性的水质监测点,于2022年3月至6月进行水样采集,选用化学需氧量(COD)、氨氮(NH+ 4-N)、总磷(TP)、溶解氧(DO)和高锰酸盐指数(CODMn)5个水质指标进行检测。基于遥感数据和土地利用数据,利用GIS软件生成4种空间尺度的圆形缓冲区域,提取了不同空间尺度的景观格局指数,采用相关分析和冗余分析(RDA),探讨了土地利用结构与景观格局对水质的影响。结果表明：①黎河水质整体偏好,总体达到Ⅱ类标准,但仍存在超标水质,其中输水期水质明显好于非输水期。多数点位COD、TP值超过Ⅱ类水质标准限值,其余水质指标年均浓度均达到Ⅱ类以内水质标准。②不同尺度缓冲半径内占地类型均以林地、耕地、建设用地为主,建设用地、水域面积比例的增加可导致水质的恶化,林地、草地增加可对水质起到提升作用。③不同空间尺度缓冲区景观格局指数对水质具有较好的解释度,500m半径缓冲区景观格局对水质的解释能力最强,解释度达59.8%,其次为1000m尺度(56.0%)。因此,加强500m半径缓冲区尺度土地利用的优化对保护流域水质具有重要意义。研究结果可为合理优化流域土地资源提供基础参考,从而保护流域水质安全。 相似文献
12.
Noelia V. Gonzalez Baffa‐Trasci Laura C. Pereyra Mauricio S. Akmentins Marcos Vaira 《水产资源保护:海洋与淡水生态系统》2020,30(7):1437-1450
- Modification and loss of natural habitats caused by human activities are among the main drivers of biodiversity decline worldwide. To evaluate how land‐use changes affect species diversity at different spatial scales, amphibians represent an excellent group given that their complex life cycle requires both aquatic and terrestrial habitats.
- In this study, the influence of wetland characteristics and surrounding landscape features on richness and functional diversity of anurans was investigated in 26 natural wetlands in a human‐modified landscape within the Southern Andean Yungas.
- The analysis was performed at two spatial scales: wetland scale (the breeding pond structure) and the surrounding landscape scale. The classification of the landscape was limited to land uses modified by human activities within concentric circular buffers (radius = 0.1, 0.2, 0.5, and 1 km) centred on each breeding pond.
- Generalized linear models were applied to investigate the relationship between environmental variables measured at different scales and anuran species richness and functional diversity, respectively.
- Pond area best explained the observed variation in both diversity measures, which is consistent with other studies on anuran diversity in disturbed landscapes. In contrast to regression models including landscape scale variables only, integrated models (which included variables on both scales) highly improved model fit.
- Conservation strategies for anuran species diversity in these altered Andean Yungas forests should include efforts to maintain or restore aquatic habitats (e.g. breeding ponds) placed within suitable landscapes.
- Successful long‐term management will require an understanding of relationships between habitat characteristics at different spatial scales to identify variables that relate to species diversity in such heterogeneous habitats.
13.
Dayani Bailly Valéria Flavia Batista-Silva Fernanda A. Silva Cassemiro Priscila Lemes Weferson Junio da Graça Anielly Galego de Oliveira Edivando Vitor do Couto José Hilário Delconte Ferreira Reginaldo Ré Thiago Fernando Rangel Angelo Antonio Agostinho 《水产资源保护:海洋与淡水生态系统》2021,31(9):2515-2532
- Freshwater ecosystems, providing valuable goods and services to humans, have been subjected to multiple human impacts, among which climate change plays a central role in threats to species. It is expected that protected areas, the cornerstone of biodiversity conservation efforts, will assume a decisive role in protecting freshwater species from the impacts of climate change.
- This study assessed the effects of climate change on migratory fish of the second largest neotropical river basin, evaluating the effectiveness of protected areas in safeguarding fish species, and hence the ecological functions that they perform and the ecosystem resources that they provide. The present range of 23 migratory fish of economic interest in the Paraná–Paraguay basin was estimated and the responses to future climatic shifts projected to the middle and end of the 21st century were examined, quantifying predictive uncertainties.
- Changes and losses of climatically suitable areas will trigger severe contractions in range, with the greatest impact on the most valuable species in commercial fishing, where range losses are likely to surpass 65% in the future. The main channel of the Upper Paraná River and tributaries of its left margin are projected to serve as climatic refuges for many species, and such regions are not affected by high predictive uncertainty. The results revealed that protected areas do not sufficiently protect migratory fish at present, and that they will continue to offer negligible protection in the face of climate change.
- This study alerts decision makers to the potential damage to inland fishery resources from climate change and provides useful information to guide conservation strategies spatially. We advocate that the creation of new protected areas and the redesign of the existing network to encompass regions that maximize current and future occupancy of migratory fish are crucial to conserve the valuable ecological, societal, and economic benefits that they provide.