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Aim: Habitat loss has been the greatest historical driver of species extinctions. A recent global trend toward retirement of marginally productive agricultural lands presents opportunities to reclaim critical habitat for endangered species. We examine habitat restoration opportunities in the context of historical sources of habitat loss, including agriculture, development, habitat fragmentation, and invasive-species-mediated climatic niche contraction. Location: California’s San Joaquin Desert (SJD) is one of the world’s most agriculturally productive landscapes. Fragments of remnant habitat serve as habitat for 34 threatened and endangered species. Retirement of agricultural land in the SJD is being driven by climate change, groundwater salinization, and historical groundwater overdraft—even as unmitigated loss of virgin habitat continues. Methods: To promote efficient habitat protection and restoration, we conducted a quantitative assessment of habitat suitability, habitat loss, climatic niche stability, projected effects of climate change, and reintroduction opportunities for an umbrella species, the endangered blunt-nosed leopard lizard (Gambelia sila). Results: Analyses indicate that G. sila habitat overlaps with occurrence records for 128 vulnerable species and that its habitat is broadly representative of the habitat of other vulnerable species in the SJD. We document an apparent climatic niche contraction for G. sila and associated range contraction away from more mesic margins of the historical distribution, apparently driven by introduction of exotic grasses and forbs. We use habitat suitability models, in conjunction with modern and historical land use maps, to estimate historical and modern rate of habitat loss to development and fragmentation. We use NASA fallowed area maps to identify 610 km2 of fallowed or retired agricultural land with high potential to be restored as habitat. We discuss conservation strategies in light of anticipated climate change and potential for habitat restoration. Main Conclusions: In the midst of multiple sources of historical and ongoing habitat loss, farmland retirement presents an opportunity to recover large amounts of endangered species habitat. |
