Changes in arthropod communities as black mangroves Avicennia germinans expand into Gulf of Mexico salt marshes

Climate change is driving poleward shifts in species distributions worldwide. In the Gulf of Mexico (GOM), warming temperatures foster black mangrove (Avicennia germinans L.) expansion into GOM wetlands replacing wetland plants including Spartina alterniflora Loisel, Salicornia depressa L., and Batis maritima L. We investigated insect community assemblages in wetlands with and without A. germinans to assess potential effects of A. germinans expansion on insect fauna. Insect abundance, biomass, richness, diversity, community structure, and feeding guild composition were measured in both the spring and the fall across three levels of A. germinans abundance. Insect abundance and biomass were larger in both the spring and the fall in wetlands where A. germinans abundance was low. Significant differences in community structure were associated with the presence of A. germinans. Feeding guild composition was also different in wetlands containing A. germinans, having less predator biomass. Shifting vegetation caused by climate change can alter insect communities in coastal wetlands, illustrating the need for a more comprehensive understanding of climate change effects on fauna in response to shifting foundation plant species.