Ghost of habitat past: historic habitat affects the contemporary distribution of giant garter snakes in a modified landscape

摘要: Historic habitat conditions can affect contemporary communities and populations, but most studies of historic are based on the reduction in extent or connectivity. Little is known about effects species distributions when has been nearly completely removed, persist a highly altered landscape. More than 93% wetlands Central Valley California, USA, have drained converted to agricultural other uses, wetlands, such as rice its supporting infrastructure canals, allow some persist. distribution giant garter snakes Thamnophis gigas, rare aquatic snake inhabiting this predominantly landscape, variables that where occurs. We used occupancy modeling examine at landscape scale Sacramento (northern portion Valley) with an emphasis relative strength (landscape-scale habitat, local microhabitat, vegetation composition prey counts) for predicting occurrence. Proximity marsh best explained variation probability occurrence scale, greater near marsh. suspect importance distance represents dispersal limitations snakes. These results suggest preserving restoring areas marsh, minimizing activities reduce marsh-like (e.g. agriculture, canal) habitats may be advantageous