Modelling the potential geographic distribution of an endangered pollination corridor in Mexico and the United States
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© 2016 John Wiley & Sons Ltd Aim: Every spring endangered Mexican long-nosed bats (Leptonycteris nivalis) migrate up to 1200 km from central Mexico to southern United States. Evidence suggests that L. nivalis follows the blooms of paniculate agave plants (genus Agave, subgenus Agave). Paniculate agave inflorescences are adapted to attract bats, and studies have indicated that Leptonycteris spp. played a key role in Agave speciation. We test the hypothesis of the Agave migratory corridor by (1) modelling the distribution of the relevant Agave species; and (2) testing whether bat records are significantly related to Agave species richness as predicted by our models. Location: Mexico and United States. Methods: We selected nine paniculate Agave species based on a set of criteria and modelled the current distribution of those species using maxent and the Genetic Algorithm for Rule-set Production (GARP), and geographic information systems to analyse the spatial correspondence of Agave richness and presence of L. nivalis. Results: We combined the Agave presence maps that resulted from the models with higher performance to create a richness map. This map indicated up to five species overlapping. L. nivalis occurrence areas correspond with areas with two, three and four Agave species more often than random expectations at the 0.05 significance level. The opposite is observed for areas with 0 Agave species where L. nivalis correspond less often than random. Main conclusions: Presence–pseudo-absence and presence–background modelling tools allowed us to map potential Agave presence. These maps could guide conservation actions to ensure the maintenance of this pollination corridor. Areas with higher number of Agave species are distributed along mountain chains and may provide foraging resources for L. nivalis for longer period of time during its migration. We recommend implementing a long-term monitoring programme in those areas to document inflorescence timing in Agave species and the presence of L. nivalis.
author list (cited authors)
Gómez‐Ruiz, E. P., & Lacher, T. E.