The effect of matrix composition in agroecosystems: assessing population structure in Heteromys mice.

Background/Question/Methods

Contemporary landscapes are being dramatically transformed by human activities. In the tropics, land transformations for agricultural production represent the majority of terrestrial landscape changes. This has resulted in extreme habitat fragmentation, leaving small patches of natural habitat surrounded by a mosaic of land uses, such as agriculture. The persistence of species living in these fragmented landscapes depends on their capacity to disperse between habitat patches. We assessed the effect of the agricultural matrix composition on the dispersal of a common rodent species (Heteromys desmarestianus) in tropical fragmented forests. We used measures of genetic distance derived from 6 microsatellite loci to estimate the effect of management intensity on genetic population structure in coffee farms located in Chiapas, Mexico.

Results/Conclusions

Our results suggest that geographical distance is the primary factor for genetic structuring among our samples. Measures of genetic distance are higher among forest fragments than between individuals collected in coffee farms and the ones in the adjacent forest.  Also genetic distances were higher among forest fragments than within them. Samples collected in more intensely managed coffee farms show slightly higher degree of differentiation with the adjacent forest fragment than those collected in the low intensity farms. These results suggest that dispersal of H. desmarestianus is influenced by habitat structure including varying degrees of shade coffee farming practice.