Fishes of a subtropical Australian saltmarsh and their predation upon mosquitoes

Synopsis The fishes occurring in a subtropical Australian saltmarsh were studied from January to December 1984 to determine the seasonal abundance and feeding of the most common species. Wide variations in pool water levels and salinity were recorded. Eight species of fish were collected, four of which are of economic importance to fisheries. Three taxa, Gambusia affinis, Pseudomugil signifer, and gobiids predominated in terms of abundance and occurrence. The abundance of fishes fluctuated markedly on a seasonal basis with few fish being taken in winter and spring (June–November) when pool water levels were low. Diets of the most common species were similar with terrestrial foods forming an important component of all diets. Feeding activity was highest in summer (December to February) when mosquito larvae, copepods, and larval coleopterans formed a large proportion of the fishes' diets. Results from the present study indicate that fish important to commercial fisheries rarely utilise the upper littoral saltmarsh habitat and that resident fishes are unlikely to effectively control mosquito larvae in saltmarsh.     

The role of connectivity and physicochemical conditions in effective habitat of two exploited penaeid species

The value of estuarine habitats is often measured by their contribution to the adult component of the population, but a broader suite of attributes can also contribute to nursery function. Identifying and quantifying these elements allows habitat repair to be effectively targeted toward improving ecosystem function for desirable species. We present a study that incorporates stable isotopes and quantitative sampling to investigate the relative importance of different estuarine areas for juveniles of exploited prawn species within the context of habitat rehabilitation, and the potential drivers of these relationships. Eastern King Prawn (Penaeus [Melicertus] plebejus) and School Prawn (Metapenaeus macleayi) were studied for two years in the lower Hunter River estuary, on the temperate east coast of Australia. The higher salinity areas near the lower end of the estuary were most important for Eastern King Prawn, and marsh systems in the lower estuary were only important for the species where there was good connectivity with oceanic water. Areas along the estuary were important for juvenile School Prawn, especially marsh habitats, and relative abundance tended to increase with increasing distance along the estuary. Designation of effective juvenile habitat for School Prawn may have been affected by high fishing mortality in fished areas, but this requires further investigation. Salinity, depth, turbidity and distance along the estuary were all important indicators of prawn distribution. The implications of these patterns for current and future habitat rehabilitation in temperate Australia are discussed.     

Nitrogen pools and soil characteristics of a temperate estuarine wetland in eastern Australia

The nitrogen status of the soil and plant components of an estuarine wetland near Sydney were investigated over 6 months to detect seasonal and spatial changes in nitrogen content. Organic carbon, organic nitrogen and inorganic nitrogen concentrations were measured in the soil at various depths in six vegetation zones across the wetland. Carbon and nitrogen content of the plant biomass were also determined in each of the zones. Soil redox potentials and pH were measured in situ and both were found to vary with depth and inundation frequency. Organic carbon, organic nitrogen and inorganic nitrogen in the soil decreased significantly from the fringe Casuarina forest (1391 g N m^?2) through to the Avicennia mangrove zone (133 g N m^?2). Exchangeable NH₄⁺, NO₃^? and NO₂^? concentrations from less than 1% of the soil nitrogen pool and vary seasonally. The distinctive feature of the mangrove zone is that the plant component of the total nitrogen pool is large (55%). This contrasts with the saltmarsh and fringe communities, where the plant pools are small (15%) in comparison with the soil. These findings are consistent with the hypothesis that mangroves export organic nutrients whereas the saltmarsh and fringe communities act as nutrient sinks.     

Coral habitat in the Aleutian Islands of Alaska: depth distribution, fine-scale species associations, and fisheries interactions

The first in situ exploration of Aleutian Island coral habitat was completed in 2002 to determine the distribution of corals, to examine fine-scale associations between targeted fish species and corals, and to investigate the interaction between the areas’ diverse fisheries and coral habitat. Corals, mostly gorgonians and hydrocorals, were present on all 25 seafloor transects and at depths between 27 and 363 m, but were most abundant between 100 and 200 m depth. Mean coral abundance (1.23 colonies m⁻²) far exceeded that reported for other high-latitude ecosystems and high-density coral gardens (3.85 colonies m⁻²) were observed at seven locations. Slope and offshore pinnacle habitats characterized by exposed bedrock, boulders, and cobbles generally supported the highest abundances of coral and fish. Overall, 85% of the economically important fish species observed on transects were associated with corals and other emergent epifauna. Disturbance to the seafloor from bottom-contact fishing gear was evident on 88% of the transects, and approximately 39% of the total area of the seafloor observed had been disturbed. Since cold-water corals appear to be a ubiquitous feature of seafloor habitats in the Aleutian Islands, fisheries managers face clear challenges integrating coral conservation into an ecosystem approach to fisheries management.     

Saltmarsh as habitat for fish and nektonic crustaceans: Challenges in sampling designs and methods

This is a review of research into the ecological role of saltmarsh as habitat used directly by fish and nektonic crustaceans such as shrimp (prawns) and portunid crabs. The quality of information about direct use of saltmarshes by nekton is poor, with even the most influential works suffering from obvious limitations. Attempts to generalize about nekton use of saltmarshes are hampered by sampling difficulties, poor sampling design, and inconsistent reporting of flooding regime and landscape structure. The difficulty in sampling nekton from shallow, vegetated marsh flats while inundated contributes to the fragmentary results of nekton work. A range of sampling methods have been described that vary in portability, size, amount of above-ground structure, escape rates of nekton, and expense; none has yet become standard. Poor experimental design in studies of saltmarsh nekton includes lack of replication, limited spatial scale, and lack of baseline data before management changes are made. Attempts to determine effects on commercial fisheries of losses in area or quality of saltmarsh by correlations between catch data and marsh loss should use active adaptive management. A second type of study, aimed at understanding how the saltmarsh is important to fisheries, can be tackled usefully at a smaller scale. To assist in the comparison of results from different studies, flooding regime should be reported as a proportion of time the marsh is submerged, and landscape structure as proportions of the marsh that are covered by intertidal flats, pools and drainage creeks. Flooding regime and landscape structure at the sites and at the time of sampling should then be put in the context of the typical pattern for the marsh under study.     

Bio-energetic data show weak spatial but strong seasonal differences in wetland quality for waders in a Mediterranean migration bottleneck

1. Assessing the quality of wetlands as refuelling areas for migrating waterbirds based on resource distribution patterns is challenging. Resources in wetlands can vary both horizontally and vertically and may be differentially available to different bird species at different times of the year. Therefore, the extent to which wetland quality can be generalised across seasons and for a diversity of birds remains unresolved.
2. Spatiotemporal variation in abundance and quality of macrobenthos as food for migrating waders was studied in a set of wetland areas near a Mediterranean migration bottleneck in the Balkan peninsula, during both spring and autumn migration. Samples were subdivided into different depth layers to differentiate between parts of the sediment that are accessible to different groups of wader species. To quantify food availability and the resulting refuelling capacity in different wetland habitat types, abundance, wet weight, and lipid and protein content of invertebrate taxa were determined for each sample.
3. Invertebrate food availability and quality were markedly higher in spring than in autumn. Given the higher abundance and protein and lipid content of prey in spring, the total energy that could be harvested in spring (3.81 ± 0.79 kJ/m²) was about 7 times higher than in autumn (0.56 ± 0.12 kJ/m²). Most prey were found in the top layer of the sediment (0–22 mm depth), but about a third of the total energy was present in the deepest soil layer that only longer-billed species could reach (55–200 mm depth). Higher quality prey items such as larger-bodied and heavier polychaetes and bivalves were found in the deeper sediment layers.
4. For other taxa, there was no evident vertical pattern of increasing individual body size. Prey abundance differed between certain habitat types but, overall, food availability could not be linked to distinct habitats. In spring, redox potential tended to be higher, while pH, vegetation cover, conductivity, and temperature were lower than in autumn.
5. Different wetland habitat classes used in a conservation framework may provide similar food resources for waders. As a result, linking food availability to habitat classifications is not straightforward. Furthermore, seasonal variation in wetland quality requires a re-evaluation of the importance of wetland areas during spring and autumn migration. Finally, nutritional analyses are essential for determining the capacity of wetlands to support refuelling by migratory waterbirds.

     

The effects of minimum map unit in coral reefs maps generated from high resolution side scan sonar mosaics

Changes in coral habitats from benthic maps at two minimum mapping units (4 and 400 m²) were examined across 600 ha at the Puerto Rico insular shelf. The maps were produced by visually interpreting high resolution side scan sonar seafloor mosaics. Comparisons were performed by using published spatial indices based on patch size and abundance. At the fine scale, small coral patches were dominant and had more complex shapes, while coarse scale maps lost information on small or rare habitats, but included new mixed habitat categories that helped conserve estimates of total habitat area. Variations in spatial indices occurred across spatial scales, but trends were not necessarily predictable. For instance, habitat diversity increased at the coarse scale maps, but habitat richness remained unchanged. Differences were related as much to the peculiarities of the abundance, shape and arrangement of habitats at the two sites as to changes in grain size.     

Linkages between seagrass,mangrove and saltmarsh as fish habitat in the Botany Bay estuary,New South Wales

Shallow-water vegetated estuarine habitats, notably seagrass, mangrove and saltmarsh, are known to be important habitats for many species of small or juvenile fish in temperate Australia. However, the movement of fish between these habitats is poorly understood, and yet critical to the management of the estuarine fisheries resource. We installed a series of buoyant pop nets in adjacent stands of seagrass, mangrove and saltmarsh in order to determine how relative abundance of fishes varied through lunar cycles. Nets were released in all habitats at the peak of the monthly spring tide for 12 months, and in the seagrass habitat at the peak of the neap tide also. The assemblage of fish in each habitat differed during the spring tides. The seagrass assemblage differed between spring and neap tide, with the neap tide assemblage showing greater abundances of fish, particularly those species which visited the adjacent habitats when inundated during spring tides. The result supports the hypothesis that fish move from the seagrass to the adjacent mangrove and saltmarsh during spring tides, taking advantage of high abundances of zooplankton, and use seagrass as a refuge during lower tides. The restoration and preservation of mangrove and saltmarsh utility as fish habitat may in some situations be linked to the proximity of available seagrass.     

Trophic consequences of terrestrial eutrophication for a threatened ungulate

Changes in primary productivity have the potential to substantially alter food webs, with positive outcomes for some species and negative outcomes for others. Understanding the environmental context and species traits that give rise to these divergent outcomes is a major challenge to the generality of both theoretical and applied ecology. In aquatic systems, nutrient-mediated eutrophication has led to major declines in species diversity, motivating us to seek terrestrial analogues using a large-mammal system across 598 000 km² of the Canadian boreal forest. These forests are undergoing some of the most rapid rates of land-use change on Earth and are home to declining caribou (Rangifer tarandus caribou) populations. Using satellite-derived estimates of primary productivity, coupled with estimates of moose (Alces alces) and wolf (Canis lupus) abundance, we used path analyses to discriminate among hypotheses explaining how habitat alteration can affect caribou population growth. Hypotheses included food limitation, resource dominance by moose over caribou, and apparent competition with predators shared between moose and caribou. Results support apparent competition and yield estimates of wolf densities (1.8 individuals 1000 km⁻²) above which caribou populations decline. Our multi-trophic analysis provides insight into the cascading effects of habitat alteration from forest cutting that destabilize terrestrial predator–prey dynamics. Finally, the path analysis highlights why conservation actions directed at the proximate cause of caribou decline have been more successful in the near term than those directed further along the trophic chain.     

Effects of local and landscape-scale habitat variables on abundance and reproductive success of wetland birds

Both local and landscape-scale habitat variables influence the abundance of wetland breeding birds. Few studies, however, simultaneously assess the effects of habitat variables at multiple spatial scales or consider effects on reproductive success. Therefore, we examined the effects of wetland and landscape-scale habitat variables on the abundance of nine breeding bird species and the effects of nest, wetland, or landscape-scale habitat variables on the nest success, clutch size, or number of fledglings of four species at 15 cattail (Typha sp.)-dominated wetlands in an agricultural region around Peterborough, Ontario, Canada. The abundance of Least Bittern (Ixobrychus exilis), Common Moorhen (Gallinula chloropus), and Marsh Wren (Cistothorus palustris) increased as wetland water depth increased; the abundance of Common Moorhen and Marsh Wren increased as wetland size increased; and the abundance of Marsh Wren increased as the amount of wetland in the surrounding landscape increased. Red-winged Blackbird (Agelaius phoeniceus) nest success decreased as nest cover increased. Clutch sizes were uninfluenced by the habitat variables that we considered. The number of Red-winged Blackbird fledglings per successful nest increased as wetland size increased and as the amount of wetland in the surrounding landscape increased. We speculate that food limitation in small wetlands may be responsible for the pattern in Red-winged Blackbird fledging success. The abundance and nest success of Virginia Rail (Rallus limicola) and Sora (Porzana carolina) were uninfluenced by the habitat variables we considered. Future research should consider mate attraction and productivity in relation to local and landscape-scale habitat variables for these and other secretive species. Our study suggests that wetland conservation will be most effective if it considers habitat variables at multiple spatial scales.     

Temporal Variations in Fish Catch Using Pop Nets in Mangrove and Saltmarsh Flats at Towra Point,NSW, Australia

Fish assemblages utilising saltmarsh and mangrove during spring tides were surveyed over a 12-month period using buoyant pop nets. A total of 48 net releases in the saltmarsh identified 16 species, at a density of 0.56 fish m⁻², with six species being of commercial importance. The same number of releases within the mangrove collected a total of 23 species at a density of 0.76 fish m⁻². However, fish density was higher within the saltmarsh than the adjacent mangrove when corrected for water volume. Multidimensional scaling revealed different assemblages of fish in the two habitats, with higher numbers of Ambassis jacksoniensis and Pseudomugil sp. in the saltmarsh and higher numbers of Mugilogobius sp. and Acanthopagrus australis in the mangrove. The result suggests a potentially significant role for saltmarsh as a fish habitat in the estuaries of southeast Australia.     

Mangroves as a habitat for fish and prawns

Mangrove inlets and creeks in Selangor, Malaysia are the habitat for 119 species of fish and 9 species of prawns. The majority of fish and all prawns sampled in the inlets were juveniles. The common fish species in the inlets in terms of weight wereArius sagor, Ambassis gymnocephalus, Liza subviridis, Toxotes jaculator, Sphyraena barracuda andLates calcarifer. Prawns were represented by juvenilePenaeus penicillatus, P. merguiensis, P. indicus, Metapenaeus brevicornis andM. affinis. Samples from enclosure traps set on mudflats during ebbing water captured 37 species of fish and 11 species of prawns. The role of mangroves as nursery and feeding grounds for fish and prawns is reviewed in the light of recent work in Selangor. It is apparent that mangroves support fisheries by providing habitat and food.     

Can spatial and temporal food variability explain the winter foraging movements of a threatened saltmarsh insectivore?

The white‐fronted chat (Epthianura albifrons) is a small, insectivorous passerine that is threatened with extinction in the north‐eastern part of its range, partially due to loss and degradation of its saltmarsh habitat. Food availability is a potential limiting factor for the disjunct populations that survive in saltmarsh refugia, surrounded by urbanized land, because the anthropogenic matrix reduces the capacity of birds to commute to alternative grassland habitat to exploit temporary insect outbreaks. This limitation is likely to be exacerbated during the winter months when local arthropod abundance in saltmarsh is reduced. This study measured temporal and spatial variation in the abundance of saltmarsh arthropods to determine whether patch switching by foraging flocks can be explained by variation in food availability. Arthropods in the size range known to be important in the diet of white‐fronted chats were vacuum‐sampled from six patches within a continuous area of Sarcocornia‐dominated saltmarsh over a four‐month period. The location of foraging birds was recorded during the same period. Despite superficial similarity in vegetation composition and structure, there was significant variation in arthropod biomass among sites through time, such that the patches with the highest food abundance changed from month to month. There was little evidence, however, to suggest that white‐fronted chats foraged in saltmarsh patches with the highest overall food abundance. During the course of the study, birds were discovered flying 2 km from the saltmarsh to a development site where they foraged in weedy grassland. Arthropod samples collected from this site contained an extremely high abundance of Hemiptera and Neuroptera larvae, supporting previous research indicating that white‐fronted chats forage on irruptions of particular arthropod taxa. These findings indicate that food abundance is unlikely to be the main determinant of foraging site selection within saltmarsh, but highlights the potential importance of alternative foraging habitat types for this species.     

Abundance,biomass, and productivity of invertebrate hyperbenthos in a temperate saltmarsh creek system

The hyperbenthos of two saltmarsh creeks at Bull Island, Dublin, Ireland was sampled to quantify its contribution to the larger trophic system of the lagoon. The brown shrimp Crangon crangon (L.) dominated in terms of both abundance and biomass. All species displayed marked seasonal and spatial variability which was reflected in the estimates for production, and especially in the vales for incremental change in biomass (δB) and mortality (M). The major contributions to production were by C. crangon and the shore crab Carcinus maenas, (L.) and to a lesser extent by Palaeomonetes varians (Leach) although the actual proportions varied according to the method used to calculate production. Total system production by the hyperbenthos in the creeks was around 20 kJ m^?2 y^?1. The contribution of hyperbenthic production was negligible in terms of overall system energy transfer to Dublin Bay, but it may play a crucial role in the saltmarsh creeks’ nursery function and trophic transfers.     

Differential habitat use by Acadian Nelson's sharp-tailed sparrows: implications for regional conservation

ABSTRACT.   Nelson's Sharp-tailed Sparrows ( Ammodramus nelsoni ) that breed along the Atlantic coast of North America (Acadian subspecies subvirgatus ) are considered saltmarsh specialists. However, these sparrows occasionally use upland habitats, such as hayfields. To evaluate the importance of hayfields as breeding habitat, we studied populations of A. n. subvirgatus in saltmarsh and hayfields in Nova Scotia, Canada, in 2004 and 2005. We monitored relative abundance and breeding phenology at 64 point-count stations (48 in hayfields and 16 in saltmarsh) and used an ordinal (0–5) observational index to quantify reproductive activity. A. n. subvirgatus showed more evidence of reproductive activity in saltmarsh (44% of point-count stations) than hayfields (28%; P = 0.07). However, there was no difference in either mean reproductive activity (saltmarsh = 0.83, hayfields = 0.53; P = 0.69) or mean relative abundance (saltmarsh = 0.27, hayfields = 0.26; P = 0.93). Although A. n. subvirgatus apparently breeds primarily in saltmarsh, hayfields appear to be an alternative breeding habitat. Use of hayfield habitat by A. n. subvirgtus , however, seems to vary between southern Maine and eastern Canada, suggesting that management plans will require approaches uniquely tailored to specific regions.     

Non-invasively determined multi-site variation in pine marten <Emphasis Type="Italic">Martes martes</Emphasis> density,a recovering carnivore in Europe

Pine martens (Martes martes) are subject to national and international conservation legislation throughout most of their European range. Yet population density and abundance estimates, which are a key component of effective conservation management, are lacking in many countries. In this study, a large-scale non-invasive survey was undertaken in 14 forested study sites throughout Ireland to assess variation in pine marten density and abundance. Pine marten hair samples were collected in each study site and analysed using genetic techniques to determine individual identity data. Density and abundance estimates were obtained using spatially explicit capture-recapture models and CAPWIRE. Across all study sites, a total of 93 individual pine marten were identified and captured 217 times. Estimated pine marten density varied from 0 to 2.60 individuals per km² of forested habitat, with all but a single site having estimated densities of ≤1 pine marten per km² of forest habitat. Mean population abundance estimates across all study sites ranged from 0 to 27 individuals. Spatially explicit capture-recapture models on combined data across all 14 study sites provided a mean density estimate of 0.64 (95% CI 0.49–0.81). Combining this with data on the current distribution and estimated area of forest habitat occupied by the species in Ireland, the total pine marten population abundance of pine marten in Ireland was estimated at 3043 (95% CI 2330–3852) individuals. This research has conducted the largest scale investigation of pine marten density and abundance in any part of its global distribution and provided an improved basis for future population assessment and monitoring of this species.     

Climatically driven changes in primary production propagate through trophic levels

Climate and land‐use change are the major drivers of global biodiversity loss. Their effects are particularly acute for wide‐ranging consumers, but little is known about how these factors interact to affect the abundance of large carnivores and their herbivore prey. We analyzed population densities of a primary and secondary consumer (mule deer, Odocoileus hemionus, and mountain lion, Puma concolor) across a climatic gradient in western North America by combining satellite‐based maps of plant productivity with estimates of animal abundance and foraging area derived from Global Positioning Systems telemetry data (GPS). Mule deer density exhibited a positive, linear relationship with plant productivity (r² = 0.58), varying by a factor of 18 across the climate‐vegetation gradient (range: 38–697 individuals/100 km²). Mountain lion home range size decreased in response to increasing primary productivity and consequent changes in the abundance of their herbivore prey (range: 20–450 km²). This pattern resulted in a strong, positive association between plant productivity and mountain lion density (r² = 0.67). Despite varying densities, the ratio of prey to predator remained constant across the climatic gradient (mean ± SE = 363 ± 29 mule deer/mountain lion), suggesting that the determinacy of the effect of primary productivity on consumer density was conserved across trophic levels. As droughts and longer term climate changes reduce the suitability of marginal habitats, consumer home ranges will expand in order for individuals to meet basic nutritional requirements. These changes portend decreases in the abundance of large‐bodied, wide‐ranging wildlife through climatically driven reductions in carrying capacity, as well as increased human–wildlife interactions stemming from anthropogenic land use and habitat fragmentation.     

Effects of exotic <Emphasis Type="Italic">Spartina alterniflora</Emphasis> on the habitat patch associations of breeding saltmarsh birds at Chongming Dongtan in the Yangtze River estuary,China

Smooth cordgrass (Spartina alterniflora) is one of the most invasive exotic plants of saltmarshes worldwide. To understand the effects of smooth cordgrass invasion on the habitat use and selection by breeding saltmarsh birds, we compared species number and abundance of breeding birds in native reed (Phragmites australis) and smooth cordgrass-invaded habitats (reed-cordgrass mixed habitats and cordgrass monocultures) at Chongming Dongtan in the Yangtze River estuary, China. We further examined the similarity of bird communities in different habitats and habitat selection by dominant bird species. For saltmarsh generalists, species number and abundance did not differ among the habitats. For saltmarsh specialists, species number and abundance did not differ in reed monocultures and reed-cordgrass mixed habitats but were significantly lower in cordgrass monocultures than in reed monocultures and reed-cordgrass mixed habitats. ANOSIM indicated that the difference in bird communities was larger between cordgrass monocultures and the habitats with reed than between the habitats with reed. The saltmarsh specialists preferred reed monocultures, while saltmarsh generalists avoided reed monocultures. Most species indicated no selection (neither preferred nor avoided) on reed-cordgrass mixed habitats, and no species preferred the cordgrass monocultures. The use of cordgrass monocultures by the common saltmarsh birds was negatively related to their body size. This study suggests that the spread of exotic smooth cordgrass has greatly affected the species composition and structure of local bird communities and has been especially disadvantageous to the saltmarsh specialists.     

Effects of habitat transitions on rainforest bird communities across an anthropogenic landscape mosaic

We compared bird community responses to the habitat transitions of rainforest‐to‐pasture conversion, consequent habitat fragmentation, and post‐agricultural regeneration, across a landscape mosaic of about 600 km² in the eastern Australian subtropics. Birds were surveyed in seven habitats: continuous mature rainforest; two size classes of mature rainforest fragment (4–21 ha and 1–3 ha); regrowth forest patches dominated by a non‐native tree (2–20 ha, 30–50 years old); two types of isolated mature trees in pasture; and treeless pasture, with six sites per habitat. We compared the avifauna among habitats and among sites, at the levels of species, functional guilds, and community‐wide. Community‐wide species richness and abundance of birds in pasture sites were about one‐fifth and one‐third, respectively, of their values in mature rainforest (irrespective of patch size). Many measured attributes changed progressively across a gradient of increased habitat simplification. Rainforest specialists became less common and less diverse with decreased habitat patch size and vegetation maturity. However, even rainforest fragments of 1–3 ha supported about half of these species. Forest generalist species were largely insensitive to patch size and successional stage. Few species reached their greatest abundance in either small rainforest fragments or regrowth. All pastures were dominated by bird species whose typical native habitats were grassland, wetland, and open eucalypt forest, while pasture trees modestly enhanced local bird communities. Overall, even small scattered patches of mature and regrowth forest contributed substantial bird diversity to local landscapes. Therefore, maximizing the aggregate rainforest area is a useful regional conservation strategy.     

盐地碱蓬盐沼与相邻泥质滩涂湿地迁徙期鸻鹬类的群落组成及行为差异

盐地碱蓬(Suaeda salsa)盐沼湿地是黄渤海地区河口区域的重要湿地类型, 是水鸟迁徙停歇期的重要栖息地。本研究以辽河口国家级自然保护区为研究地点, 通过对盐地碱蓬盐沼湿地和相邻泥质滩涂两个固定样区连续三年的水鸟组成调查和行为观察, 分析盐地碱蓬盐沼湿地在鸻鹬类多样性维持和栖息地利用中的作用。共记录到鸻鹬类水鸟28种6,348只次, 其中盐地碱蓬湿地记录到4科13种, 泥质滩涂记录到4科27种, 泥质滩涂的物种多样性显著高于盐地碱蓬盐沼湿地。此外, 盐地碱蓬盐沼湿地与相邻的泥质滩涂的鸻鹬类鸟类群落组成存在较大差异, 盐地碱蓬盐沼湿地的鸟类群落组成以体型较大的大杓鹬(Numenius madagascariensis)、白腰杓鹬(N. arquata)、灰鸻(Pluvialis squatarola)等为主, 而泥质滩涂以环颈鸻(Charadrius alexandrinus)、黑腹滨鹬(Calidris alpina)等小型鸻鹬类为主, 这说明两种生境在鸟类多样性维持中具有不同的功能。行为分析发现, 泥质滩涂中栖息鸟类的主要行为为取食(58.71%-93.26%), 而盐地碱蓬盐沼湿地鸟类的行为既包括较大比例的取食, 也包括休息, 特别是在春季迁徙期。这进一步说明, 两种生境在水鸟的栖息地利用中具有一定的生态功能差异。尽管盐地碱蓬盐沼湿地记录到的鸟类物种数和数量均低于泥质滩涂, 但是, 两种生境中存在较大比例的共同分布物种, 这说明其生态功能具有较强的生态互补性, 二者作为一种独特的湿地景观组合, 在鸻鹬类迁徙停歇期的栖息地利用和物种多样性维持中发挥着不可替代的作用。