Spatial and temporal ecology of eastern spadefoot toads on a Florida landscape
Effective amphibian conservation must consider population and landscape processes, but information at multiple scales is rare. We explore spatial and temporal patterns of breeding and recruitment by eastern spadefoot toads (Scaphiopus holbrookii), using nine years of data from continuous monitoring with drift fences and pitfall traps at eight ephemeral ponds in longleaf pine-wiregrass sandhills. Breeding events (>25 adults at a pond within a month) occurred 23 times on nine occasions at seven of the eight study ponds, but substantial recruitment (>100 metamorphs) followed only five events. Recruitment ranges from 0-4648 among ponds. Only four ponds functioned as population "sources", and only during some years. The other ponds, and even "source" ponds during some years, functioned either as "sink", where breeding occurred with no resulting recruitment, or were not used at all for breeding. Most recruitment occurred during four years. Recruitment was correlated with adult breeding effort, but only during some years. Recaptures were rare, and inter-pond exchange of adults was minimal and short-distance (<130 m; one was 416 m). Most (83.5%) individuals captured were metamorphs, and 15.9% were >51 mm (est. >4 yr). We conservatively estimated a 7-yr lifespan. Adult "population" trends clearly reflected breeding effort rather than numbers per se; capture rates fluctuated dramatically among years, but showed no overall trends during the 9-yr study. Our paper is provides empirical information that can be used to generate realistic metapopulation models for S. holdbrookii as a tool in conservation planning.