Landscape drivers of connectivity for a forest rodent in a coffee agroecosystem

Abstract

The majority of remaining tropical forests exist as fragments embedded in a matrix of agricultural production. Understanding the effects of these agricultural landscapes on species dispersal is crucial in the development of successful conservation planning. The objective of this study was to examine the influence of five landscape features within a coffee agroecosystem (i.e., slope, elevation, streams, riparian effect, and tree cover) on Heteromys desmarestianus goldmani gene flow. We expected that landscape variables linked to more intense agricultural management (e.g., low tree cover, riparian effect) would reduce gene flow in H. d. goldmani. This study was conducted in a 4 km × 2 km area within the coffee growing region of Soconusco in Chiapas, Mexico. We used 12 microsatellite markers to calculate individual-based estimates of gene flow as a measure of dispersal. We used resistance surface modelling, using ResistanceGA (Peterman in Methods Ecol Evol 9:1638–1647, 2018) to identify if any of the landscape features analyzed explained the patterns of gene flow. Our results showed patterns of population structure and weak isolation-by-distance, as found previously for H. d. goldmani by Otero Jimenez et al. (Conserv Genet 19:495–499, 2018). Slope and tree cover were the two landscape features that could best explain gene flow patterns. More specifically, intermediate slopes and tree cover represent the lowest resistance to gene flow for H. d. goldmani and, thus, have a role in promoting gene flow in this species. This study highlights the potential of integrating molecular and landscape data to explore population connectivity of elusive species, such as terrestrial small mammals. Our study adds to the growing body of literature in landscape genetics by demonstrating that a rodent species shows population structure at a small scale resulting from landscape factors linked to agricultural management.