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Many of the world’s lagoons and estuaries, representing the most important habitat for shorebirds, are increasingly degraded, often associated with dramatic declines in shorebirds, particularly in Asia. We investigated effects of hydrology on shorebird communities of two coastal lagoons of a Ramsar site in south-east Sri Lanka. One of the lagoons (Bundala) experienced natural water level fluctuations, while the other (Embilikala) had high stable water levels (>10 cm), maintained by inflows from irrigated agriculture. These inflows dramatically affected composition and abundance of shorebird communities and their prey. Tactile and visual foraging shorebirds were consistently more abundant on Bundala than Embilikala lagoon. Their feeding efficiency was significantly (50%) higher on Bundala, where large (500 μm) benthic prey were more abundant than on Embilikala. Contrastingly, small (60 μm) planktonic prey dominated the hydrologically stable Embilikala lagoon where pelagic foraging shorebird species dominated the shorebird community. On both lagoons, visual and tactile species foraged predominantly in shallow water (1–10 cm). Pelagic shorebirds also foraged in water depths >10 cm but 20% less efficiently than in shallower water. Effective shorebird conservation depends on reducing anthropogenic impacts that detrimentally affect functional processes and habitat value. The detrimental effect of altered hydrology on Embilikala lagoon could be reversed by diverting drainage water. Re-establishing a natural hydroperiod, would increase the productivity of the lagoon for foraging shorebirds. Restoration of shorebird habitat on this Ramsar site could also improve other ecosystem services such as fisheries and tourism. Changes to the hydrology of coastal lagoons elsewhere may be similarly affected.

As natural wetlands have disappeared around the world, artificial wetlands have increased. We found interesting differences in waterbird communities of two natural (Bundala Ramsar site) and seven artificial wetlands (irrigation tanks, salt ponds, rice paddies) in south-east Sri Lanka. Eight species exclusively used natural and one species artificial wetlands. Migratory species (shorebirds 64%, terns 47%) dominated species’ richness of natural lagoons, with densities of shorebirds 3–6 times greater than on artificial wetlands. Contrastingly, resident species (dabbling ducks, gallinules) contributed most to the diversity (59%) and density of waterbirds on artificial irrigation tanks. Cattle egrets dominated waterbird density (>70%) of rice paddies. Waterbird communities reflected physical and chemical character of wetlands: natural wetlands were shallow ( 1000 msm −1 ) compared to deep (>2 m) and freshwater (EC −1 ) artificial wetlands. Artificial inputs of water drained into the natural Embilikala lagoon changing its physico-chemical profile and disrupting the natural seasonal drying. Consequently its waterbird community was similar to artificial irrigation tanks, with shorebird species particularly impacted: densities half that of the other natural lagoon. Artificial salt ponds had similar physico-chemical properties to the natural Bundala lagoon and a similar waterbird community. Even though artificial wetlands supported waterbirds, they were not adequate replacements for loss of natural wetlands, favouring some species. Imposed hydrological stability degraded habitat quality for migratory shorebirds on one of our Ramsar site lagoons.

The biodiversity values of the wetlands in the Kakadu Region of northern Australia have been recognised as being of national and international significance, as demonstrated through their listing by the Ramsar Convention on Wetlands. Analyses of the wetland biodiversity have resulted in the production of species list for many taxa, and some population and community-level analyses of biomass and abundance, and the mapping of habitats at multiple scales. Wetland habitats include inter-tidal mud-flats, mangroves, hyper-saline flats, freshwater flood plains and streams. The tidal influence on the saline wetlands is pronounced, as is the influence of the annual wet-dry cycle of the monsoonal climate on the flood plains and streams. The vegetation is diverse and highly dynamic with rapid turnover of organic material and nutrients. The fauna is abundant with endemism being high in some habitats. Most fauna analyses have focussed on vertebrates with a large amount of information on waterbirds and fish in particular. However, despite extensive effort over the past two decades much is still unknown about the biota. While the invertebrate fauna in the streams has received some attention, a large taxonomic classification effort is required. The functional inter-relationships between habitats and species have largely not been assessed. Further, the ecology of many species is only cursorily known. At the same time there has been increased attention to pressures on the wetlands, such as weeds and feral animals, water pollution, and the potential impact of climate change and salinisation of freshwater habitats. Importantly, given the social context of the region, increased attention is being directed towards traditional use and management of the wetlands.

Asia is experiencing an alarming rate of inland wetlands loss, posing a risk to the future long-term survival of many species depending on these ecosystems. This review on the status and conservation of the little curlew (Numenius minutus) aims to draw attention to the conservation challenges faced by migratory shorebird species using the inland wetlands of the East Asian–Australasian Flyway (EAAF). Extensive and systematic research survey efforts along the EAAF have focused on species using coastal and tidal areas rather than on species using inland wetlands. Knowledge gaps include functional ecology and physiological responses to quality of food resources, population trends, migratory strategy and the role species play in supporting ecosystems resilience. Studies using remote sensing and geographic information system techniques to track the movements of birds along the flyway and to map habitat condition will prove essential in the future to allow a better understanding of the dynamics occurring at the stopover areas, how birds use resources and what competition pressures exist among species. Ultimately, these studies will contribute to our ability to predict changes and establish management practices for the long-term protection and conservation of the stopover areas for a suite of shorebird species using inland wetlands along the flyway.

Australia’s north supports many wetlands. The biodiversity of these wetlands is highly regarded, but many are increasingly being affected by well recognised pressures that result in adverse change in their ecological character. The extent of the knowledge base and causes of adverse change in Australia’s tropical wetlands are reviewed with an emphasis on the linkage between direct and indirect drivers of change. Within the context of the existing knowledge base, an integrated model for collecting information on the ecological character of tropical wetlands is proposed. The model encompasses hierarchical and multi-scalar approaches to wetland inventory, assessment and monitoring and was developed largely from research undertaken in northern Australia. It is based around the concepts of wise use and maintenance of the ecological character of wetlands, which in turn emphasises the value of wetlands to people through the delivery of ecosystem services. A broader conceptual framework linking ecosystem services and human well-being to the condition of wetlands is introduced as a forerunner to considering research needs for tropical Australian wetlands. The integrated model and framework entail community consultation and the involvement of stakeholders in decisions about wetland research and management. In conclusion, it is emphasised that the maintenance of the ecological character of the wetlands of northern Australia is a task for wetland managers, users and owners in collaboration with scientists from many disciplines.