An interdisciplinary approach to understanding the changing distribution of mangrove crabs affected by erosion in Mayotte

International audience ; The loss of natural habitats is generally associated with a loss of biodiversity that will cause a change in the functioning of ecosystems and consequently in their capacity to provide ecosystem services. As ecosystem engineers, mangrove crabs fulfil key ecological roles in the structure of the mangrove ecosystem through burrowing and in the functioning through nutrient cycling and bioturbation. They are also of societal and economic interest that can be used by the populations. In the West Indian Ocean, there are gaps in knowledge on the identification and distribution of mangrove crab species. This challenges our understanding of the consequences of mangrove erosion on the associated biodiversity. For example, between 1950 and 2016, the mangroves of Mayotte have been affected by a moderate regression of 6%. This loss is likely to impact the distribution of crabs and consequently the structure and functioning of the ecosystem. The objective of this study is to understand the impact of mangrove erosion on the distribution of crabs through an interdisciplinary approach combining methodologies in ecology, human geography and geomorphology.The combination of these methodologies allows access to data at several temporal and spatial scales. The characterisation of erosion rates since 1950 and consequences on sedimentary movements at large temporal and spatial scales will be provided by geomorphology data. The human geography data provides access to a medium temporal scale on the characterisation of the evolution of the distribution of crabs at the scale of the bay over the last decades. At a finer scale, by replacing time by space, the ecology data will ensure a comparison of two zones representing two different instants of the mangrove erosion trajectory.This study focuses on the mangroves of Dapani and Mzouazia, located on the southern coast of Mayotte Island. We focus on the central and sea mangroves because have been in major decline since 1950. The Mzouazia mangrove covers 3 ha, ...