A climate adaptation strategy for Mai Po Inner Deep Bay Ramsar site: Steppingstone to climate proofing the East Asian-Australasian Flyway

Abstract

The ecological functionality of the East Asian-Australasian Flyway is threatened by the loss of wetlands which provide staging and wintering sites for migrating waterbirds. The disappearance of wetland ecosystems due to coastal development prevents birds from completing their migrations, resulting in population declines, and even an eventual collapse of the migration phenomenon. Coastal wetlands are also under threat from global climate change and its consequences, notably sea level rise (SLR), extreme storm events, and accompanying wave and tidal surges. The impacts of SLR are compounded by coastal subsidence and decreasing sedimentation, which can result from coastal development. Thus, important wetlands along the flyway should be assessed for the impacts of climate change and coastal subsidence to plan and implement proactive climate adaptation strategies that include habitat migration and possibility of coastal squeeze. We modelled the impacts of climate change and decreasing sedimentation rates on important bird habitats in the Mai Po Inner Deep Bay Ramsar site to support a climate adaptation strategy that will continue to host migratory birds. Located in the Inner Deep Bay of the Pearl River estuary, Mai Po's tidal flats, coastal mangroves, marshes, and fishponds provide habitat for over 80,000 wintering and passage waterbirds. We applied the Sea Level Affecting Marshes Model (SLAMM) to simulate habitat conversion under two SLR scenarios (1.5m and 2.0m) for 2050, 2075, and 2100 for four accretion rates (2mm/yr, 4 mm/yr, 8 mm/yr, 15 mm/yr). The results showed no discernible impact to habitats until after 2075, but projections for 2100 show that the mangroves, marshes and tidal flats could be impacted in almost all scenarios of SLR and accretion. Under a 1.5m SLR scenario, even at low tide, if accretion levels decrease to 4 mm/yr, the tidal flats will be inundated and with a 2 mm/yr accretion the mangroves will also be inundated. Thus, important shorebird habitats will be lost. During high tide the ponds inside the nature reserve, which are intensively managed to provide high tide roosting sites and other habitats for waterbirds, will also be inundated. Thus, with a 1.5m SLR and declining sedimentation the migratory shorebirds will lose habitat, including the high tide roosting habitats inside the nature reserve. The model also indicates that the fishponds further inland in the

Ecological Correlates of 20-Year Population Trends of Wintering Waterbirds in Deep Bay, South China

“…Habitat transformation along the coast of China, especially in the Yellow Sea area, has caused prominent declines of several species; this is supported by the studies revealing declines of species that rely on Yellow Sea as essential stopover sites at wintering sites in Japan, Australia, and New Zealand (Amano et al, 2010;Murray et al, 2015Murray et al, , 2017Studds et al, 2017). Besides habitat transformation, waterbirds of the EAAF also experience a wide range of other threats (Wang et al, 2018), including hunting (Gallo-Cajiao et al, 2020), alien invasive species (Gan et al, 2009), pollution (Zhao et al, 2016), and climate change (Iwamura et al, 2013;Wikramanayake et al, 2020).…”

Effectively Incorporating Small Reserves into National Systems of Protected and Conserved Areas

“…Cabo Roja Salt Flats National Wildlife Refuge on the island of Puerto Rico is only 522 ha but is a critical stopover site for migrating shorebirds in the Caribbean [37] and is part of the Western Hemisphere Shorebird Reserve Network. The Mai Po Marshes nature reserve at 113 ha is a small wetland located in Hong Kong and is an internationally significant wetland that is actually a shallow estuary supporting globally important numbers of wetland birds, which chiefly arrive in winter and during spring and autumn migrations, including over 55,000 migrating birds such as Saunders's gull (Chroicocephalus saundersi), a quarter of the world's Black-faced spoonbill (Platalea minor) population, and significant numbers of Spoon-billed sandpiper (Calidris pygmaea) [38].…”

Coastal Melaleuca wetlands under future climate and sea-level rise scenarios in the Mekong Delta, Vietnam: vulnerability and conservation

“…Nevertheless, SLAMM has been shown to be effective in simulating wetland changes in other studies of tropical coastal regions (Li et al 2015;Payo et al 2016;Wikramanayake et al 2020;Dang et al 2022). Wu et al (2015) suggested that SLAMM could be an effective approach to simulate coastal wetland changes with the use of accurate data and meaningful evaluation of the simulation outcome.…”

“…SLAMM uses high-resolution spatial data to simulate wetland changes in response to SLR at landscape scales and so is capable of predicting wetland dynamics in response to SLR with higher accuracy in comparison to other methods (Craft et al 2009;Clough et al 2010;Wu et al 2015). The model has been successfully applied in the USA (Mcleod et al 2010) and some other regions around the world (Akumu et al 2011;Li et al 2015;Wu et al 2015;Payo et al 2016;Fernandez-Nunez et al 2019;Prado et al 2019;Raw et al 2020;Wikramanayake et al 2020;Dang et al 2022). Amongst these previous studies, Dang et al (2022) demonstrated that SLAMM is capable of simulating changes of mangrove wetlands in response to SLR in the Mekong Delta by using elevation data with high-vertical accuracy and precise localized parameters.…”