Assessing species reintroduction sites based on future climate suitability for food resources.

The reintroduction of a species that is extinct in the wild demands caution because reintroduction locations may be associated with threats, such as hunting, poor-quality habitat, and climate change. This is the case for Cyanopsitta spixii (Spix's Macaw), which has been extinct in the wild since 2000. The few living individuals were created in captivity and will be used in a reintroduction project within the species' original distribution area, the Caatinga domain (Brazil). Because the occurrence records for this bird are old and inaccurate, we investigated the current and future environmental suitability of the 14 plant species used by C. spixii as resource. These plants are key elements for the long-term reestablishment of the species in the wild, so the use of models helps in the assessment of the effects of climate change on the availability of these resources for the species and informs selection of the best places for reintroduction. We based our models of environmental suitability on 19 bioclimatic variables and nine physical soil and topography variables. Climate projections were created for the present and for the year 2070 with an optimistic (SSP2-4.5) and a pessimistic (SSP5-8.5) climate scenario. Both future climate scenarios lead to a reduction in area of environmental suitability that overlapped for all the plant species: 33% reduction for SSP2-4.5 and 63% reduction for SSP5-8.5. If our projections materialize, climate change could thus affect the distribution of key resources, and the maintenance of C. spixii would depend on restoration of degraded areas, especially riparian forests, and the preservation of already existing natural areas. The Caatinga domain is very threatened by habitat loss and, for the success of this reintroduction project, the parties involved must act to protect the species and the resources it uses.