Dwarf mangrove (shrubland) on shingle

Description

Sparsely vegetated coastal ecosystem, characterised by dwarf Avicennia shrubs growing on intertidal shingle and rocky tidal flats. This environment tends to occur in areas exposed to low-moderate wave action that have not accumulated deep sediments characteristic of other mangrove ecosystems.

Assessment summary

Conceptual models suggest this ecosystem is threatened by sea level rise and will likely be drowned as result of erosion of substrate and lack of accommodation space to support ecosystem migration. Furthermore, it is highly restricted and occurs as two very small patches that are considered at risk of collapse when subject to catastrophic tropical storms, which are known to occur in the region. The time taken for re-establishment may extend beyond decades, given the slow growth rates on rocky substrates, during which time increasingly frequent storms and sea-level rise could disrupt the regeneration process. The ecosystem therefore qualifies as Critically Endangered under Criterion B1 and B2.