Interior swale of the slowly-subsiding Cat Island, Mississippi, U.S.A.
Located off the eastern fringe of the subsiding Mississippi delta complex, this slowlysinking siliciclastic island is the western extent of the Mississippi-Alabama barrier chain. The Cat Island progradational ridge complex is comprised of several exquisite, densely vegetated, strandplain generations welded together throughout the early-late Holocene. This photo displays one of several tidally influenced, medium salinity (10-15 g L-1), east-west trending, dune-swale systems. It depicts the complexity of barrier island ecology, sharp ecotones and zonation, as well as the importance of threshold elevation. In the foreground of the photo, we see the calm interior waters and quick transition from saline tolerant, low-marsh (Spartina alterniflora), black needle rush (Juncus roemerianus), and high marsh (Spartina patens), to the less saline tolerant woody stemmed vegetation consisting of baccharis (Baccharis halimifolia), wax myrtle (Morella cerifera), yaupon holly (Ilex vomitoria), slash pine (Pinus elliottii var. elliottii), and sand live oak (Quercus geminata). The century old climax community stands of sand live oak are located on the highest ridges of the most central portions of the island and theoretically will eventually out-compete and replace the slash pine. The forested portion of the island is a nesting home to a diverse population ofmigratory and non-migratory birds such as snowy plover (Charadrius nivosus), least terns (Sternula antillarum), great blue heron (Ardea herodias), and osprey (Pandion haliaetus). (Photograph taken on 10 September 2014 by William (Bill) Funderburk, Gulf Coast Geospatial Center, University of Southern Mississippi, Long Beach, Mississippi, U.S.A.)