Sea level rise versus habitat enhancement for the Schaus’ swallowtail butterfly (Heraclides aristodemus ponceanus), a paradox?

The Schaus’ swallowtail (Heraclides aristodemus ponceanus) is an endangered butterfly restricted to coastal hardwood hammocks in the Florida Keys. Coastal hardwood hammocks are vulnerable to severe storms, hurricanes, human development, and rising sea levels. The Schaus’ swallowtail habitat enhancement project in Biscayne National Park designated five restored sites to increase the number of hostplants for the Schaus’ swallowtail. Hostplant mortality was significantly higher at Adams Key than Elliott Key. Soil samples revealed higher salt content at the restored sites in Adams Key than Elliott Key. Sea level rise (SLR) projections from the Army Corps of Engineers speculate a SLR ranging from 1.6 – 4.9 ft. by year 2100. Maps using GIS were generated to infer habitat loss with slow (1.6 ft.), intermediate (3.3 ft.), and fast scenarios (4.9 ft.). If projected SLR followed the fast scenario, only an estimated 25% of hardwood hammock would be left intact. Adams Key restored sites are most at-risk losing significant habitat at slow and intermediate SLR projections. Elliott Key is considered the source island for the Schaus’ swallowtail, which is less at-risk than the other islands. More effort should be devoted to protecting and enhancing Elliott Key to shield the Schaus’ swallowtail from extinction.