Crooks, J. A. Scripps Institution of Oceanography, jcrooks@ucsd.edu
Talley, T. A. Scripps Institution of Oceanography, sinicrope@coast.ucsd.edu
Levin, L. A. Scripps Institution of Oceanography, llevin@ucsd.edu

 
ECOSYSTEM ALTERATIONS BY NON-INDIGENOUS HABITAT MODIFIERS IN CALIFORNIA COASTAL WETLANDS
 
Habitat modification (or ecosystem engineering) is a major means by which non-native species can affect resident ecosystems and biota. One species that may fundamentally transform invaded ecosystems is the Australian isopod, Sphaeroma quoyanum. Through its extensive burrowing activities, this bioeroder can destroy salt marsh edges and cause loss of marsh habitat. Sampling in San Diego and San Francisco Bays reveals that the species is typically found on vertical banks underlying succulent marsh on either exposed bay-fronts or in tidal creeks. In these locations, the isopod's burrowing can alter shear strengths of sediments and increase local erosion rates. Although at broad spatio-temporal scales the isopod may cause the loss of marsh habitat, at smaller scales the burrows created by the isopod increase structural complexity and can facilitate some macrofauna. Similar scale-dependent effects are observed for the mat-forming, exotic mussel, Musculista senhousia, which inhibits large bivalves but facilitates small macrofauna on intertidal flats. Such results emphasize that the consequences of habitat alteration operate at a number of scales within ecosystems.
 
Day: Wednesday, Feb. 3
Time: 04:30 - 04:45pm
Location: Eldorado Hotel
 
Code: SS18WE0430E