Type: journal article

Article abstract: Conservation management under human-induced changes to disturbance requires tools that can balancethe needs of multiple species with different life histories and habitat requirements. Despite this urgentconservation need, landscape management typically focuses on single species and rarely includes theinfluence of disturbance-dependent vegetation transitions on multiple target species. In this paper, wedescribe a simulation model that achieves these goals, ranking possible fire management strategies fromthe viewpoint of protecting endangered coastal Southern Californian wildlife. The model involves thedirect and indirect effects of fire on four animal species of conservation concern (coastal cactus wren,California gnatcatcher, Stephens’ kangaroo rat, and Pacific pocket mouse) and five vegetation types (grass,coastal sage scrub, obligate seeding and resprouting chaparral, resprouting-only chaparral, and wood-lands). Using historical fire records for the region, we predicted spatially-explicit fire frequencies andignition probabilities. For these predictions, we simulated the location and extent of fires. Combining firehistory and vegetation transition data from 1933 to 2003, we specified vegetation change probabilitiesunder simulated fire regimes. Fire occurrence in a location altered habitat suitability, directly for each ofthe animal species and indirectly by changing the vegetative community. For some open-habitat species,such as the Stephens’ kangaroo rat and Pacific pocket mouse, fairly frequent fire is required to reduce thedensity of invasive grasses and herbs. For other species, such as the coastal cactus wren and Californiagnatcatcher, frequent fire destroys the mature coastal sage scrub on which these species depend. Themodel includes a management component, allowing us to rank fire management actions. Over a 50-yeartime horizon, we find that populations of California gnatcatchers and Pacific pocket mouse are highlyvariable, and the pocket mouse is particularly prone to decline, despite prescribed burns designed toboost population viability. California gnatcatchers were also likely to be extirpated in the model, withrelatively small extirpation risks for the cactus wren and Stephens’ kangaroo rat. Despite conflictingrequirements with respect to fire and differing life history traits among the four animals, we identified abeneficial strategy for our four target species, namely, controlling fire in coastal sage scrub.