data_distribution_Terebralia

Describing the distribution of species, especially in heterogeneous habitats, should be done at scales allowing the identification of underlying processes causing spatial and temporal patterns. The gastropod Terebralia palustris is an engineer of mangrove ecosystems, a heterogeneous habitat. Our understanding of its distribution is limited and uneven across the western Indo-Pacific. In Mayotte (France, Indian Ocean), its presence has been detected within 13 out of the 29 landward mangrove stands. The degree of spatial patchiness, however, has never been characterized across sites and within its suitable habitat. The aim of this study is to characterize degree of patchiness across sites and between seasons in order to assess the role of habitat amount and quality in explaining the species distribution. For this purpose, the distribution of patches was mapped within 10 mangroves during both the wet and dry seasons of 2021. Our results show that the distribution of T. palustris is both patchy within the landward mangroves and variable seasonally and across mangroves. The larger the landward mangrove, the bigger the number and mean size of patches, while the dry season was characterised by a higher number of smaller patches. These results highlight that both the habitat heterogeneity and availability of the landward portion of mangroves contribute to explaining the species patchiness.