Rapid Reclamation and Degradation of Suaeda salsa Saltmarsh along Coastal China’s Northern Yellow Sea

Abstract

Suaeda salsa saltmarshes are an important coastal wetland habitat of China’s northern Yellow Sea, which plays a critical role in sequestering carbon (blue carbon), protecting shorelines, maintaining biodiversity, and has substantial economic value (e.g., ecotourism). However, the area of S. salsa has been rapidly declining due to several different threats from reclamation and invasive species that impact its natural succession. Here, we map the changes in the distribution of the S. salsa saltmarshes along the northern Yellow Sea of China (NYSC) at 5-year intervals by applying the supervised maximum likelihood method to analyze Landsat images from 1988 to 2018 and investigate the potential impact of three important factors on habitat change by analyzing the temporal changes in S. salsa saltmarshes with other land covers. S. salsa saltmarsh areas have decreased by 63% (264 km2 ha to 99 km2), and the average loss of S. salsa saltmarshes was 5.5 km2/year along the NYSC over the past three decades. There have been many dramatic declines in the two main distribution areas of S. salsa saltmarshes with a 77% loss of habitat area in Liaodong Bay (from 112 km2 to 26 km2) and a 52% loss in the Yellow River Delta wetland-Guangli-Zhima estuarine wetland (from 137 km2 to 65 km2). Land reclamation is the most important impact factor in the loss of S. salsa saltmarshes, while there have been limited effects of natural succession and smooth cordgrass (Spartina alterniflora) invasion. In light of the important ecological services and economic value of the S. salsa habitat, emergency conservation actions (e.g., habitat restoration, strictly supervision) are needed to limit the rapid habitat loss, which should include the immediate cessation of extensive land reclamation along the NYSC.

Mammalian predators and vegetated nesting habitat drive reduced protected area nesting success of Kentish plovers, Yellow Sea region, China

“…Uneven sampling between the two areas was caused by the cessation of research licenses being issued for the nature reserve in 2020 due to the COVID‐19 pandemic, and no permissions were granted to access the private land of the non‐PA during 2018 and 2019. The breeding sites in the PA are located on the west side of the Liaohe river, mainly composed of bare land habitat with sparse S. salsa vegetation restored from formerly used/abandoned local fishery shellfish ponds since 2016 and 2017 (Zhang et al, 2021). Following the abandonment of the small‐scale shellfish ponds, these sites were restored primarily to recreate breeding areas for the endangered and globally threatened Saunders Gull, but have since also been colonized by several other breeding shorebird species including Kentish plover and Pied avocet ( Recurvirostra avosetta ).…”

Ecological restoration of tidal flat and its effects on soil characteristic and bacterial community

“…showed that human land reclamation was the main reason for the loss and fragmentation of Suaeda salsa saltmarshes from 1988 to 2018. [ 6 ] The rapid degrade of large areas of coastal marine ecosystems worldwide and the lack of effective techniques for reversing this trend have triggered growing interest in recent years. [ 7–10 ]…”

“…[5] Recently, Zhang et al showed that human land reclamation was the main reason for the loss and fragmentation of Suaeda salsa saltmarshes from 1988 to 2018. [6] The rapid degrade of large areas of coastal marine ecosystems worldwide and the lack of effective techniques for reversing this trend have triggered growing interest in recent years. [7][8][9][10] In response to widespread declines, a growing number of coastal restoration projects have been conducted in the past decades all around the world, including marsh and mangrove restoration, phytoremediation of coastal saline soil, oyster reefs restoration, seagrass and kelp restoration, living shorelines construction.…”

Assessing the Ecosystem Health of Coastal Wetland Vegetation (Suaeda salsa) Using the Pressure State Response Model, a Case of the Liao River Estuary in China

“…However, from 1988 to 2009, the entire wetland has been in a state of degradation due to natural and human factors (e.g., aquaculture ponds and drought), especially the ‘red beach’ landscape consisting of the S. salsa community, which not only constrains the development of the local tourism industry but also threatens the wetland’s ecological health [ 6 , 7 ]. Degradation also exists in other coastal wetlands in China, such as the Yellow Sea [ 8 ]. In recent years, the shrinking of the “red beach” has received widespread attention from the government, and, in 2015, a wetland ecological restoration project was launched to restore the beach to its original state.…”