首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 46 毫秒
1.
Stormwater wetlands are a common part of urban and suburban landscapes. These constructed wetlands provide first-order treatment of effluent from roads, parking lots, lawns and other surfaces. They also provide habitat for wetland-associated birds. Thus, there is a concern that birds may be attracted to potentially toxic habitats. This study assesses nesting success and forging behavior of Red-winged Blackbirds (Agelaius phoeniceus) in retention stormwater wetlands based on drainage type. Drainage categories included residential, commercial, and highway sites. Commercial sites had the lowest nesting success and the lowest diversity of invertebrate foods. Mean nest success values for all three types of wetlands, especially for highway drainages, were comparable to published values from natural wetlands. Over two years of study highway ponds collectively served as source populations whereas residential and commercial sites were population sinks in one year and sources in the other. Red-wings using highway sites had the highest foraging efficiency as determined by the frequency and duration of forays. Residential sites had the greatest human disturbance and generally had intermediate-quality habitat and nesting success. We conclude that while stormwater wetlands collect run off and accompanying pollutants, they can still be valuable habitats for nesting birds in urban and suburban areas. We recommend a few management strategies that can increase avian use of these habitats.  相似文献   

2.
Reinelt  Lorin  Horner  Richard  Azous  Amanda 《Urban Ecosystems》1998,2(4):219-236
This paper summarizes the results of the Puget Sound Wetlands and Stormwater Management Research Program, which examined the impacts of urban stormwater on wetlands. Results are presented for data collected between 1988 and 1995 for 19 wetlands, showing changes in wetland hydrology resulting from urban conversion and the subsequent impacts on plant and amphibian communities. The amount of watershed imperviousness, the forested area, and the degree of outlet constriction were found to be the most significant factors affecting wetland hydroperiods. As hydroperiods changed, plant communities shifted towards communities adaptable to the new hydrograph. Wetlands with water level fluctuation above 20 cm resulted in lower plant richness in the emergent and scrub-shrub zones. Similarly, wetlands with water level fluctuation greater than 20 cm were significantly more likely to have low amphibian richness of three or fewer species. A primary goal of the research program was to employ the results to improve the management of both wetlands and stormwater in urban areas. Hydrologic guidelines were applied to King County's basin planning and master drainage planning efforts. Controls that focused on minimizing impervious surfaces and maximizing forest retention in the wetland watershed proved to be the most widely usable strategy.  相似文献   

3.
Evaluating wetlands within an urban context   总被引:22,自引:3,他引:19  
Coastal regions are among the most rapidly urbanizing places on earth. The numerous effects of urbanization on hydrology, geomorphology, and ecology make wetlands in urban regions likely to function differently from wetlands in non-urban lands. Furthermore, wetlands in urban regions may take on human-related values that they lack in non-urban areas, as they provide some contact with nature, and some opportunities for recrea-tions that are otherwise rare in the urban landscape. Evaluations of the success of restorations in urban regions require that criteria first determine the kinds and intensities of urban influence on the site, and then secondly assess functional performance. The development of success criteria, at both levels of assessment, depends on the proper definition of a reference domain (the set of wetlands to which success criteria will apply), and the documentation of a set of reference sites within the domain; both must be based within the urban context appropriate for the region of interest. An example is presented from a study of urban wetlands in New Jersey of a procedure for establishing the reference domain, the reference set of wetlands, and criteria for the assessment of urban influence.  相似文献   

4.
Urbanization creates new habitats with novel benefits and challenges not found in natural systems. How a species fares in urban habitats is largely dependent on its life history, yet predicting the response of individual species to urbanization remains a challenge. While some species thrive in urban areas, others do poorly or are not present at all. Mountain chickadees (Poecile gambeli) are year-round residents of montane regions of western North America. Commonly found in higher-elevation coniferous forests, these birds can also be found in urban areas where they will regularly visit bird feeders and nest in nest boxes. We monitored mountain chickadees nesting along a habitat gradient, from natural habitat to suburban areas, to determine if the degree of urbanization was associated with: clutch size and success; nestling growth rates; or variation in parental size and age. Females nesting in urbanized areas initiated clutches earlier in the breeding season than those in natural areas, but neither fledging success nor the rate of nestling mass-change differed between habitats. Nestling feather growth-rate increased with later first egg dates in both habitats, and the magnitude of this increase was greatest in urban habitats. We found no difference in the proportion of first-time breeders versus experienced breeders between habitat types, nor any differences in male or female mass or size. Our results indicate no detriment to nesting in urban habitats, suggesting mountain chickadees are able to adapt to moderate urbanization much like other members of the Paridae family.  相似文献   

5.
Constructed, created and restored wetlands are gaining popularity in urban areas due to many ecosystem services they provide. However, there is a concern over mosquito breeding in such wetlands. We studied factors affecting mosquito populations in two experimental flow-through created wetlands, a stormwater wetland, a pond and 40 mono-specific and mixed plant mesocosms (1?m2) at the Olentangy River Wetland Research Park (ORWRP) in Columbus, Ohio. The flow-through created wetlands had less mosquito larval density (2 to 4/dip) compared to the pond (36.2?±?8.4/dip) (p?<?0.00001) and stormwater wetland (24.9?±?10.2/dip) (p?=?0.002). Sites with higher larval density in the flow-through wetlands were outflow regions (p?=?0.009) and emergent vegetation sites (p?=?0.023). Mixed vegetation communities consisting of Sparganium eurycarpum, Juncus effusus, and Schoenoplectus tabernaemontani rather than mono specific Typha communities provided most conducive environment for mosquito breeding (p?<?0.0001). Mesocosm plots with steady inflow (10?cm depth) and deep water (20?cm) in summer and shallow water (5?cm) in spring had higher mosquito densities than mesocosm plots with other hydrological conditions. Among water quality parameters, conductivity (p?=?0.004) positively and dissolved oxygen (p?=?0.052) negatively correlated with mosquito larval density. Six mosquito species identified in all water bodies were Culex pipiens, Culex salinarius, Culex restuans, Uranotaenia sapphirina, Anopheles quadrimaculatus, and Anopheles punctipennis some of which may transmit deadly human pathogens. This information will be useful for targeting mosquito populations in specific sections of urban created wetlands and to develop improved designs for urban wetlands.  相似文献   

6.
Urban areas are increasing in number, extent, and human population density worldwide. There is potential to mitigate negative impacts of urbanization to native pond-breeding amphibians by providing habitat in both remnant natural and constructed wetlands. This study examines amphibian use of potential breeding sites in natural and constructed ponds in a large metropolitan area to investigate habitat characteristics that are associated with successful breeding. I surveyed 62 ponds over three breeding seasons in Portland, Oregon, measuring eleven habitat characteristics that may influence their successful breeding: pond depth, nitrate level, aquatic refugia, aquatic vegetation, surrounding vegetation, pond permanence, presence of fish and of introduced bullfrogs, surrounding road density and forest cover, and whether they were constructed or remnant natural ponds. Five of the six native pond-breeding species that occur in the region were regularly found breeding in city ponds. Surrounding forest cover and amount of aquatic vegetation were highly associated with breeding, indicating that preserving and planting vegetation likely benefits urban amphibians. Non-native bullfrogs were not associated with native species richness. Surprisingly, whether a pond was natural or constructed was also only weakly associated with native species breeding, and the trend was towards higher presence for all species in constructed ponds. This indicates that novel, human-dominated areas can provide habitat for these species. Consideration of habitat characteristics associated with breeding success in urban pond management will likely benefit native amphibians in these rapidly expanding landscapes.  相似文献   

7.
Does urbanization affect key life-history traits in native organisms? Some studies show that urban areas reduce diversity in certain taxa, but there is little insight into how these environments affect physiological and ecological traits. Urban areas have distinct physical structure and ecological processes compared to original habitats. The environmental changes associated with urban areas can influence the costs and benefits of different traits and behaviors of local organisms. Some of these effects have been explored in groups such as birds, but we might expect stronger effects in animals with reduced mobility, such as amphibians. Importantly, the effects of urban habitats on amphibians have not been explored, in spite that these are the most threatened vertebrate group in the world. Here, we compared three main traits related to the fitness of amphibians in urban and natural habitats: body size, body condition and immune response. To test the generality of our results, we assessed adult males of four amphibian species. We found that the body size was larger in urban environment populations in three of four studied species, while the body condition was better in the urban populations of two aquatic newt species. Finally, we found no effect of urbanization on the immune response of individuals of any species. In conclusion, we show that different species of amphibians may be affected differently by anthropogenic habitat alteration depending on their specific ecology.  相似文献   

8.
Stormwater basins are commonly employed structures designed to mitigate the negative effects of urban runoff. They are ubiquitous in the urbanized landscape; yet the effect of these basins on anurans has only recently been addressed. Stormwater basins have the potential to influence the breeding distribution of anurans by being sources for some species and sinks for others. Our study aims to determine which species benefit from the existence of stormwater basins, which species are negatively impacted, and what variables are the best predictors of these effects. We monitored thirty-six permanently-ponded basins in southern New Jersey for the presence of anuran larvae and calling males by aural surveys, dip-netting and trapping. We assessed fish presence by interviews, visual encounters, dip-netting, and traps. We divided near shore buffer areas into impervious surface and managed or unmanaged categories for both grass and woody vegetation. Two connectivity metrics, distance to canopied corridor and percent of undeveloped upland were analyzed with ArcGIS. Fish were detected in 92% of the basins. Resistance to fish predation distinguished successful species, those with larvae present, from unsuccessful species, those with calling activity but no larval presence. Connectivity to and availability of terrestrial habitat were significant predictors of the breeding species richness at the basins. Number of calling species increased as access to and amount of terrestrial habitat increased. Therefore, design, management, and placement of permanently-ponded basins can impact anuran communities. Additionally, as wet basins are sources for Rana catesbeiana, where bullfrogs are invasive, basins will likely increase propagule pressure.  相似文献   

9.
Hadeda Ibis (Bostrychia hagedash) have increased in population size and expanded in range in South Africa possibly as a result of increased use of exotic trees for nesting and roosting in urban areas. We investigated the urban nesting and roosting sites of the Hadeda Ibis by measuring tree height and species used by Hadeda Ibis for nesting and roosting in Pietermaritzburg, KwaZulu-Natal, South Africa. We expected Hadeda Ibis nests and roosts to have habitats, like wetlands, to be within 10 km of the roost or nest tree. Hadeda Ibis nest and roost locations were mapped using ArcGIS and available resources (grasslands, wetlands, plantations, other natural water sources) 10 km around each roost and nest tree were determined. Results showed that Hadeda Ibis use exotic trees for nesting and roosting in urban areas more than indigenous trees. This may be because exotic trees are more available in urban environments, particularly those trees that have ornamental value. Hadeda Ibis did not nest and roost closer to expected resources. Although previously associated with wetlands, Hadeda Ibis in urban environments were not close to natural water sources. This can be explained by swimming pools providing accessible drinking water and well watered lawns providing suitable foraging habitat therefore allowing them to roost and nest in this urban habitat.  相似文献   

10.
Restoration of ecosystem functions in urban environments is made challenging by 1) a public that often lacks understanding of ecological principles, 2) inadequate evidence of the effectiveness of restoration practices, and 3) difficulty integrating social and biophysical factors in studies of urban ecosystems. This paper describes a case study in which potential solutions to these challenges were explored. We facilitated collaborative learning through public participation in the design and implementation of an urban riparian buffer along a headwater stream in a neighborhood park, a process that was informed by ecological research. Learning outcomes were evaluated using surveys and qualitative assessment of discussion. Results indicated that participants’ knowledge about water quality problems associated with urbanization, stormwater, and nonpoint-source pollution increased, familiarity with stormwater management practices increased, and perceptions about the importance of stream ecosystem functions changed. In-stream monitoring of sediment delivery, as well as direct measurements of buffer infiltration capacity, provided early evidence of buffer effectiveness in prevention of sediment inputs to the stream and absorption of runoff from surrounding surfaces. This study provides a useful model for integration of collaborative learning through participation, ecological restoration, and ecological research in an urban setting. Elements deemed essential to success of this model included an opportunity for dialog focused on a specific natural feature, sustained interaction between participants and researchers, opportunities for hands-on participation by urban residents, and flexibility in restoration practice installation.  相似文献   

11.
Animal body sizes in urban areas often differ from nearby rural areas, which may impact population fitness and dynamics. We examined the effects of urbanization on larval body sizes of two species of salamanders, the two-lined salamander (Eurycea cirrigera) and the northern dusky salamander (Desmognathus fuscus). Specifically, we utilized a before-after control-impact (BACI) study design which allowed for the assessment of differences in larval body size between multiple control and impacted sites over a 5 year period. We found a decrease in larval body size in both species at the impacted sites compared to control sites in the first year after urbanization, followed by generally larger body sizes in urban sites compared to control sites in years 3–5, and significantly so in year 4. Using generalized linear models, we found support that larger body sizes post impact in urbanized streams may be due to warmer stream water temperature and decreased abundance of larvae. Both E. cirrigera and D. fuscus are well known for their ability to persist in urbanized streams; our data suggest that despite overall lower abundances in urban streams, persistence may be due to increases in larval body size and, potentially, post-metamorphic benefits.  相似文献   

12.
Green infrastructure (GI) is gaining wide popularity as a means to reduce urban stormwater runoff. The challenges to long-term success of many GI policies, however, depend on citizen understanding and willingness to be engaged in the process of GI implementation. In this study, we developed a conceptual model that incorporated human preferences and biophysical processes in a coupled manner to estimate stormwater runoff variation at the sewershed scale under different acceptable GI implementation scenarios. To investigate resident receptivity toward GI implementation, we conducted surveys in selected Syracuse sewersheds and developed the scenario of residents implementing rain barrels and rain gardens in their private properties based on the survey results. We simulated this scenario at the lot level using the model we developed within the framework of the EPA SWMM 5 model to estimate reductions in peak flow and total runoff volume for major storm events. With our model, we also tested the effect of planned government tree planting scenarios. The scenario simulations were applied in three urban sewersheds of varying socio-economic and biophysical structures in the City of Syracuse, New York. The simulation results indicated that both the “government participation” and “household participation” scenarios, compared to pre-GI-development conditions, would contribute to a modest reduction in stormwater peak flow (>4 %) and total runoff volume (>5 %) across the simulated sewersheds. This study provides decision makers with a scientific methodology to quantify how human decisions can shape ecosystem function, and thus support sustainable stormwater management planning while addressing citizen preferences and needs.  相似文献   

13.
Streams and rivers have essential roles in landscape connectivity; however, urban watersheds are frequently modified to drain stormwater from urban areas. To determine whether an earthen stormwater drain in an urban landscape provides fish habitat temporally, we compared the fish assemblage among three reaches of a contiguous urbanized watershed in Kanata, Ontario, Canada. Watts Creek is connected to an earthen municipal surface stormwater drain (herein Kizell Drain), before discharging into the Ottawa River. We delineated transects in three reaches of the system, in Watts, in the Drain, and below their confluence (Main) and assessed the fish community using single-pass electrofishing repeated across eight months covering all seasons. Fish community composition was compared among reaches using non-metric multidimensional scaling (NMDS) and permutated multivariate analyses of variance (perMANOVA). Sign association tests identified indicator species driving assemblage patterns among reaches. Redundancy analysis (RDA) was used to assess the influence of physical characteristics of the transects on fish assemblage structure. Finally, fish assemblage measures were separated by month and temporal comparisons of fish assemblage were performed with NMDS and perMANOVA. Over the year, fish assemblages were distinct among the three reaches, and appear to be significantly influenced by temperature, undercut banks, and riparian vegetation type. Biotic homogenization in the Drain can be attributed to degraded physical features associated with channel modification in stormwater drains. Despite management and jurisdictional differences between streams and stormwater drains, evidence that earthen stormwater drains can maintain fish assemblages temporally demonstrates their biological potential and need to be considered as interconnected fish habitat elements within the overall watershed.  相似文献   

14.

Elevated levels of different contaminants are typical to stormwater management ponds. Despite that, a number of works report stormwater ponds serving as habitats for a variety of biota. In this study we aimed to examine phytoplankton communities of urban ponds, as the basis of the aquatic food web, and compare them to those of natural shallow lakes. Stormwater ponds were selected from two distant geographic locations: three in Denmark and three in Canada. As a reference to natural systems, three Danish shallow lakes were sampled. The sampling was carried out in the spring, summer and fall of 2014. The phytoplankton communities in ponds were found to be at least as rich in taxa as natural shallow lakes. Their abundance and biovolume varied highly among the types of water bodies as well as in each pond or lake individually, depending on the sampling month. We did not find any significant differences among ponds and natural shallow lakes at the investigated taxonomic level, despite some distinction observed by multivariate DCA and CCA analyses. Little difference was found between Canadian and Danish ponds as well, even though they are separated by a large geographic distance. This study shows that stormwater ponds are habitats for diverse planktonic algae communities which have some similarities to those of natural shallow lakes. Also, the similarities observed between Danish and Canadian ponds indicate some consistence with the urban homogenization hypothesis, although this should be further looked into by future works examining a larger number and distinct types of ponds.

  相似文献   

15.

Managing stormwater and wastewater has been a priority for cities for millennia, but has become increasingly complicated as urban areas grow and develop. Since the mid-1800s, cites often relied on an integrated system of underground pipes, pumps, and other built infrastructure (termed gray infrastructure) to convey stormwater away from developed areas. Unfortunately, this gray infrastructure is aging and often exceeds its designed capacity. In an effort to alleviate issues related to excess stormwater, many urban areas across the United States are interested in using green infrastructure as a stopgap or supplement to inadequate gray infrastructure. Green infrastructure and other greenspace promote interception and/or infiltration of stormwater by using the natural hydrologic properties of soil and vegetation. Furthermore, there are numerous ancillary benefits, in addition to stormwater benefits, that make the use of greenspace desirable. Collectively, these ecosystem services can benefit multiple aspects of a community by providing benefits in a targeted manner. In this paper, we present a framework for balancing stormwater management against ancillary benefits of urban greenspace. The framework is structured around the Millennium Ecosystem Assessment ecosystem service categories: provisioning, cultural, regulatory, and supporting services. The purpose is to help communities better manage their systems by 1) allowing stakeholders to prioritize and address their needs and concerns within a community, and 2) maximize the ecosystem service benefits received from urban greenspace.

  相似文献   

16.
There are a variety of land use types in urbanized areas that may have different effects on the ecological characteristics of patches of natural vegetation. In particular, residential housing and industrial land-use may have different effects on adjacent forest communities. We tested this hypothesis by examining the vegetation of forested wetlands in a densely urban region, northeastern New Jersey. Wetlands embedded in industrial areas were much less invaded by exotic plant species than were wetlands embedded in residential areas, as reflected in the number of exotic species, the fraction of the total flora that was exotic, and their frequencies of occurrence. Few other structural characteristics of the vegetation differed between the two types of urban areas. We suggest that the management of land adjacent to forest edges may explain this surprising result. The low rate of invasion of wetlands within industrial areas suggests they could have high conservation value in urban ecosystems.  相似文献   

17.
This study investigated the impacts of urban wetlands and their adjacent residential environments on the transmission dynamics of West Nile virus (WNV) within the state of New Jersey (USA). A working hypothesis was that urban wetlands decrease the local prevalence of WNV through the dilution effect from increased bird diversity, and through relative reductions in the numbers of competent avian host and mosquito species commonly associated with WNV. Surveys of mosquito and bird communities were undertaken at six urban wetlands and their adjacent residential environments over two seasons (2009, 2010). The community compositions of both avian and mosquito species differed significantly across habitats, and over relatively short geographical distances. Residential areas contained significantly higher proportions of WNV-competent mosquito species (31.25?±?5.3?%; e.g. Culex pipiens and Culex restuans), and WNV-competent avian host species (62.8?±?2.3?%, e.g. House Sparrow and American Robin) when compared to adjacent urban wetlands (13.5?±?2.1?%; 35.4?±?2.1?% respectively). Correspondingly, WNV infection rates within local Culex spp. populations indicate that WNV was more prevalent within residential areas (28.53/1000) compared to wetlands (16.77/1000). Large urban wetlands (>100?ha) produced significantly lower weekly WNV infection rates in local Culex spp. (6.67?±?2.84/1000) compared to small (<15?ha) wetlands (22.57?±?6.23/1000). Avian species richness was also influenced by patch size. Large urban wetlands contained significantly more species than small wetland patches. These results confirm that the community compositions of mosquito and avian hosts are important drivers in WNV infections, and that the ecological conditions that favor transmission are more strongly associated with urban residential environments than with adjacent urban wetlands.  相似文献   

18.

Urbanization has significantly increased globally during the last century and has far-reaching consequences for biodiversity and their associated habitats, particularly wetland ecosystems. Previous studies have focused primarily on wetlands in non-urban areas, and urban wetland biodiversity patterns are currently not well understood, particularly across Africa. Here, we investigate two highly transformed urban wetlands in Cape Town, South Africa, and determine the relative importance and influence of local environmental variables as drivers of macroinvertebrate richness and community structuring. We also determine the influence of local environmental variables for patterns of species turnover and nestedness within and among these wetlands, and provide management recommendations based on our findings. We found that few macroinvertebrate species were associated with these wetlands, yet community variation was driven by a combination of local environmental variables. Our results also indicate that the turnover component of beta diversity, rather than nestedness, was responsible for most of the variation in the overall macroinvertebrate community. We identified two major problems regarding the current ecological state of the investigated wetlands. Firstly, high nutrient loads originating from the surrounding land uses which reduced wetland biodiversity, and secondly, the transformation of these wetlands from seasonal to perennial water bodies. We recommend local and regional scale approaches to limit urban waste from entering these systems, and management of water levels simulating natural Mediterranean-type climate dynamics more closely are required to ensure that the maximum possible diversity can be supported in these wetlands.

  相似文献   

19.
Plant-based stormwater management systems such as green roofs are typically composed exclusively of vascular plants. Yet, mosses have several desirable properties that could warrant their more widespread use in green roof applications. In natural systems mosses are important primary colonizers of bare ground, and their establishment improves water storage and provides numerous soil benefits including carbon and nitrogen sequestration. Additionally, mosses often facilitate the establishment and survival of vascular plants at otherwise environmentally harsh or stressful sites. Despite their potential value, few studies have investigated the functional performance of mosses on green roofs. In this study we evaluated the establishment success and potential stormwater performance of three candidate moss species. We also directly compared the runoff and thermal characteristics of replicate moss covered green roofs to vascular planted and bare roofs. Candidate mosses had high water holding capacities, storing 8–10 times their weight in water compared to only 1.3 times for typical green roof medium. Mock-up roof sections composed of mosses and medium had delayed and reduced runoff flows relative to medium only sections, although the magnitude of these effects varied with moss species. In field trials all three mosses survived a harsh rooftop environment with limited summer irrigation, although lateral growth after one year was minimal. Green roofs planted solely with Racomitrium canescens had between 12–24% higher stormwater retention than vascular or medium only roofs. Moss cover also ameliorated temperature fluctuations on green roofs. Hourly heating rates were buffered to a similar degree (less than half that of surface temperatures) 5 cm below the surface of both moss covered and medium only roofs. In contrast, cooling under the surface of the moss roof was nearly 6 times faster than under the medium only roof. These results demonstrate the potential for mosses to be valuable components of green roofs, either in combination with vascular plants or planted exclusively.  相似文献   

20.
Urbanization is a pervasive and growing threat to amphibian populations globally. Although the number of studies is increasing, many aspects of basic amphibian biology have not been investigated in urban settings. We reviewed 32 urban studies from North America and quantified the number of species studied and their response to urbanization. We examined existing research on breeding habitats, life-history stages, movement patterns, and habitat use relative to urbanization. We found amphibians as a whole respond negatively to urbanization (69 reported responses were negative, 6 were positive and 35 showed no effect). We caution, however, that many North American species still lack or are associated with conflicting information regarding species-specific responses (e.g., 89 potential responses were unknown). Approximately 40% of all anuran and 14% of caudate species in North America were investigated in the literature; however, the most diverse genera (e.g., Plethodon and Eurycea) were the most understudied likely due to their cryptic terrestrial lifestyles and biases in sampling protocols that assess wetland habitats via call surveys. Research on movement and small scale habitat use was deficient. Adult, juvenile, tadpole, and egg mass life-history stages commonly served as direct measures of species presence and abundance; however, such data do not accurately reflect recruitment into subsequent age classes and population persistence. The lack of data on many North American species may be contributing to poor management of urban amphibian populations and their habitats.  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