| I evaluated the efficacy of a vertebrate umbrella species, the California Gnatcatcher, in representing the conservation needs of two butterflies, Euphilotes bernardino (Lycaenidae) and Apodemia mormo (Riodinidae), and a moth, Hemileuca electra (Satumiidae), in southern California coastal sage scrub. Additionally, I used molecular sequence data from the mitochondrial Cytochrome Oxidase I (COI) gene to contrast the systematic and conservation status of the taxa in the H. electra and H. maia/nevadensis species complexes. Finally, I constructed a molecular phylogeny for the genus Hemileuca using COI and a nuclear gene, Elongation Factor 1 alpha (EF1alpha), and I propose hypotheses about the evolution of some ecological and morphological characters across the genus.; The use of surrogate, or 'umbrella', species as shortcuts in conservation planning has become increasingly common. Surrogate species are assumed to confer conservation protection to co-habitant taxa. Despite their importance in ecosystems, invertebrates have generally been ignored in conservation planning. This practice of focusing conservation attention on vertebrates has been commensurate with the tacit assumption that invertebrate cohabitants will be saved automatically by vertebrate surrogates. I tested this assumption by comparing the occurrence of an endangered bird, the California Gnatcatcher, used as an umbrella species in southern California coastal sage scrub, against the presence of three sage scrub dependent Lepidoptera, Euphilotes bernardino, Apodemia mormo, and Hemileuca electra . All three insects fly and are assumed to be relatively mobile compared to most invertebrates. If these lepidopterans are unable to maintain populations in isolated patches of sage scrub in which they originally occurred, then the majority of less vagile invertebrates are likely to be more severely impacted by habitat fragmentation. I conducted surveys for the three insect species in 50 patches of sage scrub in San Diego county. The bird was present on all but one of the sites---significantly more than any of the insects. Therefore the presence of the gnatcatcher does not serve as an indicator for the presence of the three insects dependent on the same habitat. Because not all remaining patches of sage scrub will be saved, use of the gnatcatcher as an umbrella species for conservation prioritization of remaining habitat patches is unlikely to save those patches on which all three insects occurred. This research refutes the assumption that vertebrate-based reserve designs will automatically preserve invertebrate cohabitants. (Abstract shortened by UMI.)... |
