The western spadefoot (Spea hammondii, SPHA) has become extirpated from most of southern California’s lowlands. Populations in northern California have suffered similar but possibly not so extensive declines. Habitat loss as well as fragmentation and degradation of habitat have contributed to declines in both areas. Fragmentation and consequent isolation also creates meta-populations that, although may not eliminate the species completely, may result in reduced or zero gene flow. Smaller cohorts are also more likely to become extirpated due to catastrophic events but may also succumb to stochastic episodes such as periods of drought or drought-like conditions.
Much of the western spadefoot’s life-history is poorly understood. The species’ current distribution is not well documented or perhaps it’s better to say that we currently know the species’ distribution through a series of snapshots rather than a comprehensive image. Its post-breeding movements are poorly understood and the specifics of the soil make-up at upland burrow sites virtually undocumented. While we’re aiming to become the clearinghouse for western spadefoot information, both current and historic, our study hopes to address the following specific tasks:
- Compile a data base of historic occurrences from museum records.
- Document recorded living records (e.g., from agency reports, project documents, California Natural Diversity Data Base records, etc.) including our own ongoing survey data, separating these by decade in order to develop a dynamic image of changes in the species’ distribution over time.
- Create a comprehensive phenological description of the species with respect to rainfall pattern, temperature, and especially to document changes that may be related to climate change.
- Provide an archival server to house photo images of the species and the habitats in which they’ve been found.
- Disseminate information about the species through our Web portal.
- Initiate field studies to track SPHA movements from breeding sites into upland refugia.