Zoogeography of the Grasshoppers and Their Relatives (Orthoptera) on the California Channel Islands
Weissman DB and Rentz DC. 1976. Zoogeography of the Grasshoppers and Their Relatives (Orthoptera) on the California Channel Islands. Journal of Biogeography. 3(2):105-114
Twelve of fifty-four Orthoptera species (22.2%) found on the eight California Channel Islands off the coast of Southern California are endemic, (11.9%) in the northern four-island subgroup and (22.2%) in the southern four-island subgroup. A general analysis of the distribution of these endemics, especially those in the cricket genus Cnemotettix and those endemic species capable of flight, was conducted. The results indicate that autochthonous speciation, and not the occurrence of mainland relicts, explains these high endemic numbers. A regression analysis of log island area versus log number of Orthoptera species yields results similar to those of other plant and animal species. Faunistically rich land masses that lie within 20 km of one Channel Island are disproportionately more important as source areas that those land masses at distances exceeding 20 km. Simple regression of environmental components correlated with faunal diversity shows that for untrasformed data, Orthoptera species numbers are significantly explained by area (82%) and elevation (74%). For log transformed data, the significance of area in explaining Orthoptera species number is diminished to 57%, while elevation explain 78%, which is almost unchanged from before transformation.
- Type
- Journal Article
- Authors
- Weissman, David; Rentz, David
- Units
- CHIS
- Keywords
- Animal Studies, Biogeography, Endemic Species, Grasshoppers & Crickets (Orthoptera), Santa Cruz Island Channel Islands National Park CA