California Crayfish and Habitat Study
Influence of local-scale and landscape-scale habitat characteristics on California spiny lobster (Panulirus interruptus) abundance and survival
Thien T. Mai A , B , C and Kevin A. Hovel A
A Department of Biology, San Diego State University, 5500 Campanile Drive, San Diego, CA 92182, USA.
B Present address: Section of Evolution and Ecology, University of California, Davis, One Shields Ave, Davis, CA 95616, USA.
This significant study may shed some light on NZ concerns that in some areas crayfish and other species may be affected by the decline of algal forest habitats due to predator removal and trophic cascade effects.
For many marine systems, little is known about the effects of habitat structure on ecological processes that dictate population dynamics. This study focused on the effects of habitat structure on behaviour, abundance, and survival of California spiny lobster (Panulirus interruptus Randall) in the Point Loma kelp forest, San Diego, California. Habitat characteristics were quantified in 400-m2 landscapes to determine the role of shelter and understorey kelp characteristics at local (shelter) scales and landscape scales on lobster habitat use. A tethering experiment determined the effects of the presence of understorey kelp on lobster survival. At the shelter scale, lobsters preferred permanent shelters to ephemeral shelters, but did not respond to shelter size. At the landscape scale, lobster density increased with Pterygophora californica (stipitate kelp) density and decreased with Laminaria farlowii (prostrate kelp) density, but lobster density did not vary with shelter density or dispersion. Lobster size increased with P. californica density in two of three surveys, while lobster size did not vary with L. farlowii density. Lobster relative survival was higher in the presence of understorey kelp than when kelp was absent. We conclude that lobsters respond to habitat characteristics at local and landscape scales, and that understorey kelp has strong effects on lobster habitat use and survival.
Keywords: behaviour, distribution, fragmentation, kelp forest, shelter, understorey kelp.
Marine and Freshwater Research 58(5) 419–428