Reduction of avian diversity in created versus natural and restored wetlands

Natural wetland ecosystems continue to suffer widespread destruction and degradation. Many recent studies argue that artificial or restored wetlands compensate for wetland loss and are valuable for waterbird conservation. However, detailed comparisons of the value of natural, artificial and restored wetlands are lacking. Our aim was to assess if the restoration or creation of wetlands can fully compensate for the loss of natural wetlands for waterbirds. We compared the waterbird communities in a set of 20 natural, restored and artificial wetlands, all of which are considered important for waterbirds and are located within the same protected area (Doñana Natural Space, south‐west Spain). We used different measures of diversity, including phylogenetic relatedness, and the proportion of threatened species at national, European and international levels. We found that artificial wetlands have consistently lower value than restored and natural wetlands, with little difference between the latter two. Natural wetlands are essential for conserving diversity across the tree of life and for threatened species, but restored wetlands can be of similar value and can assure maintenance of key ecological processes. Thus, when economic costs per unit area are similar, resources for wetland conservation are better invested in restoration projects than in wetland creation, and caution is required when suggesting that artificial wetlands compensate for the loss of natural wetlands.     

Are artificial wetlands good alternatives to natural wetlands for waterbirds? – A case study on Chongming Island, China

Loss of natural wetlands is a global phenomenon that has been a serious threat to the wildlife. A common practice is to construct artificial wetlands to compensate for the loss of natural wetlands. To test whether artificial wetlands as habitats for waterbirds are good alternatives to natural wetlands, we compared species richness, abundance, and seasonal dynamics of waterbird communities of natural (here tidelands) and artificial wetlands (here aquacultural ponds) on Chongming Island, China. Our results indicate that habitat preference of waterbirds showed seasonal difference: most of the shorebirds were found on tidelands in spring, whereas most of the natatorial birds were recorded in aquacultural ponds in winter. Waterbirds preferred the tidelands rather than aquacultural ponds in both spring and autumn, whereas they showed no preference for either the tidelands or the ponds in summer and winter. It is concluded that natural wetlands are better habitats for waterbirds than artificial wetlands on Chongming Island, while the artificial ones are also suitable habitats for waterbirds in winter. The waterbirds might use artificial wetlands only when natural wetlands are unavailable or of poor quality. An over-emphasis that artificial wetlands are suitable habitats for waterbirds might encourage land managers to convert natural wetlands into the artificial ones, resulting in considerable loss of bird diversity. Therefore, for the purpose of bird conservation, it would be a better practice to conserve natural wetlands rather than to construct artificial ones after destruction of natural wetlands.     

How can Habitat Selection Affect the use of a Wetland Complex by Waterbirds?

The factors regulating the distribution of dabbling and diving waterbirds were studied, taking into account habitat selection by the species in a wetland complex of 26 ponds in south-eastern Spain. Such information can be used to management and conservation of wetland threatened bird species. Direct counts and feeding-microhabitat surveys of waterbirds were conducted. The feeding-niche width and the feeding-microhabitat use, as a function of the horizontal spatial gradient in the ponds, were related to the mean size of ponds used for each species. While the more generalist birds, which usually feed close to the shore, probably had available resources in small ponds, specialists that also frequently selected central zones of the pond had proportionally more limited feeding space and, therefore, less resource availability in small ponds. The differences in habitat selection of the different species appeared to encourage their hierarchical disappearance from the wetland complex at the same rate as the ponds diminished in size (‘nested’ pattern). The results support the conservation, restoration or creation of, at least, ponds of greater size in order to preserve extensive open-water zones in the wetlands and maintain the greatest number of specialist, threatened, and area-dependent species, such as the globally endangered White-headed Duck (Oxyura leucocephala).     

Restoration of wetlands in the Mississippi–Ohio–Missouri (MOM) River Basin: Experience and needed research

An ecological and hydrologic restoration of the Mississippi–Ohio–Missouri (MOM) Basin in the United States is proposed as the solution to the reccurring hypoxic conditions in the Gulf of Mexico. Nitrate–nitrogen is the cause of this eutrophication in the Gulf and its source is mainly due to increased fertilizer use in the American Midwest. In that same Midwest, the land has also been artificially drained and 80–90% of the original wetlands have been lost. Our proposed restoration involves the strategic creation and restoration of 2.2 million ha of wetlands in the MOM basin where in-field wetlands intercept agricultural runoff and diversion wetlands are overflowed by flooding river water. Case studies that total 50 wetland-years of data from Illinois, Ohio, and Louisiana are summarized as the basis for the restoration area estimate. Benefits of this restoration, in addition to solving the Gulf hypoxia, include water quality improvement, reduction of public health threats, habitat creation, and flood mitigation that will accrue to the locations in the MOM basin where the restoration occurs. Before the restoration commences, there is a need for formal and rigorous large-scale research in the basin to reduce uncertainties.     

Aerial survey of waterbirds on wetlands as a measure of river and floodplain health

1. This study highlights the use of waterbird communities as potential measures of river and floodplain health at a landscape scale. 2. The abundance and diversity of a waterbird community (54 species) was measured over 15 trips with four aerial and three ground counts per trip on a 300-ha lake in arid Australia. 3. Aerial survey estimates of individual species were significantly less precise (SE/mean) than ground counts across two (11–100 and > 1000) out of four abundance classes of waterbirds: 0–10, 11–100, 101–1000 and > 1000. Standard error/mean as a percentage decreased with increasing abundance from about 60% for the lowest abundance class to 18% for the largest abundance class. 4. Aerial survey estimates were negatively biased for species in numbers of less than 10 and greater than 5000 but unbiased compared to ground counts for other abundance classes. Aerial surveys underestimated numbers of waterbirds by 50% when there were 40 000 waterbirds. Three ground counts found about seven more waterbird species than four aerial surveys. One ground count took about 150 times longer than two aerial surveys and cost 14 times more. 5. Regression models were derived, comparing aerial survey estimates to ground counts for 31 of 36 species for which there were sufficient data. Aerial survey estimates were unbiased for most of these species (67%), negatively biased for six species and positively biased for one species. Estimates were negatively biased in species that occurred in small numbers or that dived in response to the aircraft. 6. River system health encompasses the state of floodplain wetlands. Waterbirds on an entire wetland or floodplain may be estimated by aerial survey of waterbirds; this is a coarse but effective measure of waterbird abundance. Aerial survey is considerably less costly than ground survey and potentially provides a method for measuring river and floodplain health over long periods of time at the same scale as river management.     

Waterbird communities and seed biomass in managed and reference‐restored wetlands in the Mississippi Alluvial Valley

The Natural Resources Conservation Service (NRCS) commenced the Migratory Bird Habitat Initiative (MBHI) in summer 2010 after the April 2010 Deepwater Horizon oil spill in the Gulf of Mexico. The MBHI enrolled in the program 193,000 ha of private wet‐ and cropland inland from potential oil‐impaired wetlands. We evaluated waterfowl and other waterbird use and potential seed/tuber food resources in NRCS Wetland Reserve Program easement wetlands managed via MBHI funding and associated reference wetlands in the Mississippi Alluvial Valley of Arkansas, Louisiana, Mississippi, and Missouri. In Louisiana and Mississippi, nearly three times more dabbling ducks and all ducks combined were observed on managed than reference wetlands. Shorebirds and waterbirds other than waterfowl were nearly twice as abundant on managed than referenced wetlands. In Arkansas and Missouri, managed wetlands had over twice more dabbling ducks and nearly twice as many duck species than reference wetlands. Wetlands managed via MBHI in Mississippi and Louisiana contained ≥1.3 times more seed and tuber biomass known to be consumed by waterfowl than reference wetlands. Seed and tuber resources did not differ between wetlands in Arkansas and Missouri. While other studies have documented greater waterbird densities on actively than nonmanaged wetlands, our results highlighted the potential for initiatives focused on managing conservation easements to increase waterbird use and energetic carrying capacity of restored wetlands for waterbirds.     

Hawaiian waterbird movement across a developed landscape

A key component for biologists managing mobile species is understanding where and when a species occurs at different locations and scaling management to fit the spatial and temporal patterns of movement. We established an automated radio-telemetry tracking network to document multi-year movement in 2016–2018 of 3 endangered waterbirds among wetlands on Oʻahu, Hawaiʻi, USA: ʻalae ʻula or Hawaiian gallinule (gallinule; Gallinula galeata sandvicensis), ʻalae keʻokeʻo or Hawaiian coot (coot; Fulica alai), and aeʻo or Hawaiian stilt (stilt; Himantopus mexicanus knudseni), each with different ecological requirements. There were marked differences in the movement propensity of the species, with no movement among sites detected in gallinules, 31% of coots moving among wetlands, and very high levels of daily movement in stilts. A network analysis revealed strong evidence for fidelity among individual stilts to specific wetlands, indicating different groups of wetlands supported different birds. There was also strong evidence for patterns in daily and seasonal movement patterns of stilts. Our work indicates the importance of each wetland to the waterbirds they support, as each individual had strong fidelity to a single wetland. In addition, for Hawaiian coots and stilts, which were documented moving among multiple wetlands, a network of wetlands may be key for long-term persistence of these endangered species, and coordinated regional management of waterbirds as a shared resource could provide greater benefits to waterbirds than independent management of each wetland.     

Partial recovery and a new population estimate of rhesus monkey populations in India

The purpose of this field study has been to assess major changes in rhesus monkey populations of north central India over a period of 28 yrs from 1959 to 1986. Population censuses have been done in Aligarh District three times per year, and extensive regional surveys were done in 1959–1960, 1964–1965, 1977–1978, and 1985–1986. Throughout the 1960s and 1970s, rhesus populations in India declined more than 90%, from an estimated 2 million animals in 1960 to approximately 180,000 by 1980. These declines were attributed to increasing agricultural pressures in India, loss of primate habitats, less protection for monkeys, and high levels of trapping. In the 1970s, as India's agricultural production rose and stronger wildlife conservation programs developed, local populations of rhesus began to increase. These increases became more prominent after 1978, when India imposed a ban on export of monkeys. By 1985 a population in Aligarh District had returned to its 1960 level in total population size, although the number of groups remained low. Other local populations showed even more striking growth and greatly exceeded former levels. Some areas of India, however, have shown no improvement in rhesus populations. Overall, extensive field surveys of rural habitats in 1985–1986 showed a 53% recovery in the number of rhesus groups, and a 129% recovery in total rhesus from their low points in 1977–1978. We estimate the rhesus population of India in 1985 in the vicinity of 410,000–460,000 individuals.     

The importance of unmanaged coastal wetlands to waterbirds at coastal Ghana

Ghana's 550 km coastline has about 100 wetlands out of which five large ones are managed as Ramsar sites, the rest being unmanaged. Recent pollution and misuse of unmanaged wetlands have necessitated a study into their roles in the support of waterbirds. Waterbird survey on four wetlands between September 2005 and April 2006 revealed that 51 waterbird species make use of the managed compared to 44 in the unmanaged wetlands. Average numbers of waterbirds were higher on the managed wetlands (10,510 ± 4862) than on the unmanaged wetlands (1348 ± 602) (P < 0.05) but mean population density of waterbirds (n/ha) was the same for both the managed (1860 ± 310) and unmanaged (1400 ± 220) (P > 0.05) wetlands. The population densities of waterbirds belonging to guilds 1, 5 and 7 were significantly higher on the managed wetlands (P < 0.05). In contrast, guilds 2 and 4 have significantly higher population densities on the unmanaged wetlands while the population density of guild 3 was the same (P > 0.05). There was an indication that during mid and late periods of the nonbreeding season, the unmanaged wetlands altogether may support a larger number of waterbirds belonging to guilds 2, 3 and 4 than the five managed wetlands.     

­­Cross-taxon congruence in wetlands: Assessing the value of waterbirds as surrogates of macroinvertebrate biodiversity in Mediterranean Ramsar sites

Wetlands are among the most threatened habitats and the species they support among the most endangered taxa. Measuring and monitoring wetland biodiversity is vital for conservation, restoration and management, and often relies on the use of surrogate taxa. Waterbirds are commonly used as flagships of biodiversity and are the subject of major conservation initiatives. Therefore, it is important to assess the extent to which waterbirds indicate the general biodiversity of wetlands and serve as surrogates.We explore the relationships between community composition and species richness of waterbirds and aquatic macroinvertebrates in 36 Ramsar wetlands in southern Spain to assess if waterbirds are good surrogates for other taxonomic groups. Specifically, we aimed to (i) test the congruence of patterns of species composition and richness among waterbirds and aquatic macroinvertebrates; and (ii) investigate which environmental variables are associated with the biodiversity patterns of waterbirds and macroinvertebrates, with the purpose of identifying key factors explaining potential discordance in these patterns.We found a limited concordance between assemblage patterns of both taxonomic groups that may be related to their contrasting responses to environmental gradients. Assemblages of waterbirds appear to be more affected by climate variables and water surface area, whereas conductivity was the most important factor influencing macroinvertebrate communities. Furthermore, we found a negligible or inverse relationship in their patterns of richness, with wetlands with higher waterbird species richness showing significantly lower richness of Hemiptera and macroinvertebrate families, and no significant relationship with Coleoptera. In addition, GLM models showed that, in general, different environmental variables are related with the richness patterns of the different taxonomic groups.Given the importance of the Ramsar convention for the conservation of an international network of wetlands, our findings underline the limited potential of waterbirds as aquatic biodiversity indicators in Mediterranean wetlands, and the need for caution when using waterbirds as flagships. An integrative analysis of different biological communities, using datasets from different taxonomic groups, is a necessary precursor for successful conservation policies and monitoring. Our results illustrate the need to create a diversified and complete network of protected sites able to conserve multiple components of wetland biodiversity.     

Comparing the diversity and composition of waterbird functional traits between natural,restored, and artificial wetlands

1. The restoration of degraded areas and the creation of artificial ecosystems have partially compensated for the continuing loss of natural wetlands. However, the success of these wetlands in terms of the capacity of supporting biodiversity and ecosystem functions is unclear. Research is needed to improve our understanding of the value of restored and constructed wetlands for functional diversity of freshwater fauna.
2. We compared natural, restored, and artificially created wetlands present within the Doñana Natural Space, Spain and valued as important for waterbirds. We evaluated if these wetlands are equivalent in terms of waterbird functional trait diversity and composition, during both the wintering and breeding seasons. We modelled functional diversity measures and functional group species richness describing species diet, body mass, and foraging techniques with generalised linear mixed models in 20 wetlands monitored between 2006 and 2011. We used three different statistical approaches to evaluate the robustness of our results.
3. Artificial wetlands constructed for conservation failed to reach the functional diversity of natural and restored wetlands. Unexpectedly, artificial ponds constructed for fish production performed better, and even exceeded natural wetlands for functional richness during winter. Fish ponds stood out as having a unique functional composition, connected with increase in richness of opportunistic gulls and decrease of species sensitive to high salinity. Overall, the functional structure of breeding communities was more affected by wetland type than wintering communities.
4. Our findings suggest that compensating the loss of natural wetlands with restored and artificial wetlands results in systems with altered waterbird-supported functions, such as seed dispersal or nutrient cycling. Protection of natural Mediterranean wetlands is vital to maintain the original diversity and composition of waterbird functional traits. Furthermore, restoration must be prioritised over the creation of artificial wetlands, which, even when intended for conservation, may not provide an adequate replacement.

     

Managing the natural capital of papyrus within riparian zones of Lake Victoria,Kenya

The harvesting of natural products such as papyrus (Cyperus papyrus L.), whether for subsistence value or for the production of commodities intended for sale at local markets, contributes to the well-being of riparian peoples around Lake Victoria, Kenya. Serious losses of papyrus wetlands across East Africa have been reported, most of which are attributed to increasing anthropogenic stressors. Recent studies have called for restoration of these wetlands, emphasizing the need for sustainable harvesting strategies to be put in place, although few have provided suggestions as to how this might happen in practical terms and, crucially, with the consent and active participation of local communities as key stakeholders. Here we explore the socioeconomic characteristics of livelihoods based on papyrus, presenting data generated from surveys, interviews and group discussions collected at multiple sites within the Nyando river basin, Kenya. Conceptualizing papyrus stands as living stocks of natural capital, we then outline our proposal for maintaining the provisioning services of this species, without compromising the critical ecohydrological functions of these swamps as land–water buffer zones. Finally we suggest how this approach might be adapted for wider dissemination around Lake Victoria and beyond, motivated by what we believe to be the first reported case of successful papyrus restoration by a local community.     

Waterbird and wetland research and conservation in Ghana: a ten year perspective

Ntiamoa-Baidu, Y. & Gordon, C. 2000. Waterbird & wetland research and conservationin Ghana: a ten year perspective. Ostrich 71 (1 & 2): 95.

The study outlines the evolution of ecological research on waterbirds and wetland conservation initiatives in Ghana over a ten year period, 1986–1996. A survey of waterbird populations was initiated in the country in October 1985, through a collaborative effort between the Ghana Government, the Royal Society for the Protection of Birds (RSPB) UK and BirdLife International. These studies identified key wetland sites on the Ghana coast which have been regularly monitored up to today, thus providing the most comprehensive long-term data on waterbird populations within the West African sub-region. Over the ten year period the simple waterbird counting has led to comprehensive ecological research on waterbirds, the establishment of a national Bird Ringing Scheme and the development of a core of trained ornithologists in Ghana. In terms of conservation action, the data provided the justification for designation of the five most important coastal wetland sites as Ramsar sites and the establishment of the Ghana Coastal Wetlands Management Project (CWMP) to manage the sites. The management strategy adopted seeks not only to maintain the ecological integrity of the wetlands, but more importantly, to enhance the benefits derived from wetlands by local communities and improve the quality of life for the coastal people. Management actions are guided by a multi-disciplinary research on the coastal wetland ecosystem, which incorporates biological, physico-chemical and socio-economic dimensions. The large body of environmental data accumulated during the initial stages of the CWMP provide a solid base for the monitoring of the ecological character of the wetlands and the evaluation of management activities. The events in Ghana clearly demonstrate the value of a strong scientific data-base in our efforts to promote conservation of Africa's wetlands and wetland resources.     

长江口滩涂围垦后水鸟群落结构的变化——以南汇东滩为例

近年来长江口滩涂湿地高强度的促淤围垦对生物多样性保育造成了严重影响。本研究于2006至2010年在南汇东滩进行了水鸟调查,研究围垦后堤内环境的快速演替过程对水鸟的群落结构的影响。通过分析鸻鹬类、雁鸭类和鹭类三类主要水鸟类群,结果表明鸻鹬类的总数呈严重下降趋势（ANOVA, p=0.009）,而雁鸭类和鹭类总数在上升（ANOVA,p=0.015;p=0.00）;在种类数量方面,鸻鹬类和雁鸭类差异不显著（ANOVA,p=0.597;p=0.523）,鹭类种类数变化极显著（ANOVA ,p=0.00）。同时,通过对水鸟的栖息地选择因子偏好的分析, 发现滩涂减少是鸻鹬类减少的主要因素,而大型鱼塘和芦苇增加是雁鸭类和鹭类增加的重要原因。为此我们提出相应海岸带湿地管理建议。     

崇明东滩鸟类栖息地优化区越冬水鸟的栖息地利用及影响因子

阐明水鸟栖息地利用与环境因子的关系有助于制定针对性的水鸟保护对策。本研究在2012~2013年冬季对崇明东滩鸟类栖息地优化区内越冬水鸟的种类、数量以及6种环境因子(植被面积比例、裸地面积比例、水深、地形变异、栖息地结构多样性和干扰)进行调查,以了解水鸟对人工湿地的栖息地利用及其影响因子。野外调查共记录到水鸟24种9 018只,其中优势种为斑嘴鸭(Anas poecilorhyncha)和绿头鸭(A.platyrhynchos);栖息地优化区内水鸟休息的个体数量占总数量的79.2%,这表明优化区是大多数水鸟的休息地,而小(Tachybaptus ruficollis)、白骨顶(Fulica atra)、黑水鸡(Gallinula chloropus)、白琵鹭(Platalea leucorodia)和黑脸琵鹭(P.minor)的觅食个体数量超过60%,说明优化区也为这些鸟类提供了觅食地。逐步回归分析表明,裸地面积比例是影响越冬水鸟种类分布的最主要因子;尽管游禽在地形变异较大、植被面积比例较低的区域数量较多,但在休息时游禽更偏好于裸地面积比例较高的区域,而涉禽休息时偏好于地形变异较大的区域。为增加栖息地优化区内的水鸟多样性,建议在优化区内种植水鸟可食的沉水植物以增加水鸟的食物资源,同时增加裸地面积比例和地形变异程度,更好地为水鸟提供栖息地。     

Hunting and the fate of French breeding waterbirds

Capsule French breeding populations of hunted waterbirds have more negative long-term population trends than closely related non-hunted species.

Aims To assess the relative fate of breeding populations of hunted and non-hunted waterbird species in France.

Methods We compared long-term population growth rates of hunted versus non-hunted waterbirds using two large-scale and long-term national surveys.

Results Waterbirds globally displayed long-term increases in population sizes most likely driven by their positive response to the implementation of numerous protected areas over remnant wetlands across the country since the early 1970s. In contrast, hunted species revealed more negative trends compared to non-hunted species.

Conclusion A causal relationship between hunting and population dynamics is not demonstrated here, but the results are consistent with species' breeding populations being negatively affected, on average, if they are hunted.     

Machine learning-based spatial-temporal assessment and change transition analysis of wetlands: An application of Google Earth Engine in Sylhet,Bangladesh (1985–2022)

Wetlands are crucial ecosystems as they enhance the quality of groundwater, protect from natural hazards, control erosion, and provide habitat to rare species of flora and fauna. Despite being valuable ecosystems, wetlands worldwide are decreasing in many regions, making mapping and monitoring of wetlands crucial. Large-scale wetlands mapping is challenging but recent advancements in machine learning, time series earth observation data, and cloud computing have opened doors to new techniques to overcome such limitations. Through evaluating the effectiveness of different classification methods, this study provides a brief analysis of wetlands dynamics in Sylhet, Bangladesh. The analysis is carried out between 1985 and 2022 using Google Earth Engine, Landsat imagery, and several spectral indices. To obtain reliable results, four classification algorithms (Random Forest, Minimum Distance, Classification and Regression Trees, and Support Vector Machine) are evaluated. As a result, Random Forest proved to be the most efficient and accurate for wetlands mapping by producing 99% accuracy across all periods. Change detection shows a rapid decrease in the wetlands in Sylhet, which could have serious consequences to the aquatic and terrestrial species, water and soil quality, and wildlife population, if not addressed. Between 1985 and 2022, nearly 45% of the wetlands have been lost in the region due to shifting land-use patterns, especially the conversion of wetlands into vegetative land (∼82,000 km²) as a result of increased agricultural practices in the region. Four critical regions (i.e., Derai, Sulla, Jamalganj, and Ajmiriganj) have undergone ∼80% reduction in wetlands, requiring prompt interventions for conservation and restoration of wetlands given their diverse services.     

Detecting soil and plant community changes in restored wetlands using a chronosequence approach

Wetland restoration aims to recreate or enhance valuable ecosystem services lost during wetland destruction. Regaining wetland ecosystem services depends on restarting basic wetland functions, like carbon (C) storage, which are unmeasured in many Wetlands Reserve Program (WRP) restoration sites. We collected soil and plant data from 17 WRP sites in western New York that were used for tillage or non-tillage agriculture and then actively restored as isolated depressional wetlands by excavating basins and disabling drainage systems. Sites had been restored for 0–15 years when sampled in August-October 2010. We analyzed data as chronosequences and tested whether soil and vegetation parameters in restored wetlands, over time, (1) departed from pre-restoration baselines, estimated using active agricultural fields paired to each WRP site, and (2) converged towards “natural” benchmarks, estimated from four naturally-occurring wetlands. Restored WRP soils remained similar to agricultural soils in organic matter, density, moisture, and belowground plant biomass across chronosequences, indicating negligible C storage and belowground development for 15 years following restoration. Soil changes were limited in sites restored after both tillage and non-tillage agriculture and throughout the upland meadow, emergent shoreline, and open-water habitat zones that characterize these sites. Many plant metrics like aboveground biomass matched natural wetlands within 15 years, but recovered inconsistently among tilled and untilled sites and across all habitat zones, suggesting land-use history impacts and/or zonation effects. Disparities in recovery times exists between vegetation, which can respond quickly to wetland restoration, and underlying soils, which show limited signs of recovery 15 years after being restored.     

Waterbird Response to Wetlands Restored Through the Conservation Reserve Enhancement Program

Abstract: Conservation programs that facilitate restoration of natural areas on private land are one of the best strategies for recovery of valuable wetland acreage in critical ecoregions of the United States. Wetlands enrolled in the Conservation Reserve Enhancement Program (CREP) provide many ecological functions but may be particularly important as habitat for migrant and resident waterbirds; however, use of, and factors associated with use of, CREP wetlands as stopover and breeding sites have not been evaluated. We surveyed a random sample of CREP wetlands in the Illinois River watershed in 2004 and 2005 to quantify use of restored wetlands by spring migrating and breeding waterbirds. Waterbirds used 75% of wetlands during spring migration. Total use-day abundance for the entire spring migration ranged from 0 to 49,633 per wetland and averaged 6,437 ± 1,887 (SE). Semipermanent wetlands supported the greatest total number of use-days and the greatest number of use-days relative to wetland area. Species richness ranged from 0 to 42 (x̄ = 10.0 ± 1.5 [SE]), and 5 of these species were classified as endangered in Illinois. Density of waterfowl breeding pairs ranged from 0.0 pairs/ha to 16.6 pairs/ha (x̄ = 1.9 ± 0.5 [SE] pairs/ha), and 16 species of wetland birds were identified as local breeders. Density of waterfowl broods ranged from 0.0 broods/ha to 3.6 broods/ha and averaged 0.5 ± 0.1 (SE) broods/ha. We also modeled spring stopover use, waterbird species richness, and waterfowl reproduction in relation to spatial, physical, and floristic characteristics of CREP wetlands. The best approximating models to explain variation in all 3 dependent variables included only the covariate accounting for level of hydrologic management (i.e., none, passive, or active). Active management was associated with 858% greater use-days during spring than sites with only passive water management. Sites where hydrology was passively managed also averaged 402% greater species richness than sites where no hydrologic management was possible. Density of waterfowl broods was 120% greater on passively managed sites than on sites without water management but was 29% less on sites with active compared to passive hydrologic management. Densities of waterfowl broods also were greatest when ratios of open water to cover were 70:30. Models that accounted for vegetation quality and landscape variables ranked lower than models based solely on hydrologic management or vegetation cover in all candidate sets. Although placement and clustering of sites may be critical for maintaining populations of some wetland bird species, these factors appeared to be less important for attracting migrant waterbirds in our study area. In the context of restored CREP wetlands, we suggest the greatest gains in waterbird use and reproduction may be accomplished by emphasizing site-specific restoration efforts related to hydrology and floristic structure. (JOURNAL OF WILDLIFE MANAGEMENT 72(3):654–664; 2008)     

安徽沿江两个浅水型湖泊越冬水鸟的季节动态(英文)

安徽沿江浅水型通江湖泊湿地是东亚-澳大利亚迁徙水鸟的重要越冬地和停歇地。近年来,高强度的渔业养殖使湿地严重退化,对越冬水鸟构成威胁。为了解湿地变化对越冬迁徙水鸟的影响,2007年11-2008年4月和2008年11月-2009年4月,对安徽菜子湖和升金湖11个样带内越冬水鸟的种类、数量及空间分布进行了调查,并分析了湖泊渔业模式对水鸟分布的影响。两个湖泊共统计到越冬水鸟7目12科43种。其中,菜子湖群38种,密度为8.2ind./hm2;升金湖42种,密度为3.5ind./hm2,优势种为鸿雁(Anser cygnoides)、豆雁(Anser fabalis)、小天鹅(Cygnus columbianus)和黑腹滨鹬(Calidris alpina)。越冬水鸟种类和数量在12月底-次年1月上旬达到最大值,但不同类型越冬群最大数量出现的具体时期有所不同。根据水鸟组成的聚类分析,可将水鸟栖息地分为三组。水鸟的分布与渔业模式有关,在自然捕捞区,鹤类、雁鸭类和鸻鹬类密度较大,在围网养殖区密度较小,而鹭类的密度在各湖区变化都较小。本研究结果提示,发展可持续渔业对于长江中下游浅水湖泊湿地越冬水鸟资源的保护具有重要意义。