IUCN Red List of Ecosystems, Mangroves of the Warm Temperate Northeast Pacific

Abstract

Mangroves of the Warm Temperate Northeast Pacific is a regional ecosystem subgroup (level 4 unit of the IUCN Global Ecosystem Typology). It includes the marine ecoregions of the South-Californian Pacific and the Gulf of California. The mapped extent of the Warm Temperate Northeast Pacific mangrove province in 2020 was 1,810.4 km², which represents 1.5% of the global mangrove area. There are three species of true mangroves that characterize the biota: Rhizophora mangle, Laguncularia racemosa and Avicennia germinans. These mangroves all grow on a southeast-northwest latitudinal axis, from greater to lesser structural complexity due to less favourable temperature conditions and availability of freshwater with increasing distance from the tropical zone. The main threats to the mangrove ecosystem in this region derive from changes in hydrological and sediment regimes, almost always related to the development of local infrastructure, such as canals and roads or the construction of upstream dams. Another emerging threat is the increased incidence of hurricanes in the region, which have affected large areas mainly in the last five years. Based on our analysis, it has been estimated that the Warm Temperate Northeast Pacific mangroves have expanded their coverage by 12.46 % since 1970. Nevertheless, the net area change has been -8.5 %. If this trend persists, it is anticipated that there will be 8.2 % reduction in coverage to 2055. Based on the IPCC RCP8.5 high sea-level rise scenario, it is estimated that the Warm Temperate Northeast Pacific mangroves will experience significant submergence of approximately 26.6 %, by the year 2060. Additionally, ~3 % of the mangrove ecosystem in the province is undergoing degradation currently, and this percentage is expected to increase to 8.7 % within the next 50 years. These estimated are based on a vegetation index decay analysis. The Warm Temperate Northeast Pacific mangrove ecosystem is currently assessed as Near Threatened (NT).