Geogenetic patterns in mouse lemurs (genus Microcebus ) reveal the ghosts of Madagascar's forests past

Abstract

Phylogeographic analysis can be described as the study of the geological and climatological processes that have produced contemporary geographic distributions of populations and species. Here, we attempt to understand how the dynamic process of landscape change on Madagascar has shaped the distribution of a targeted clade of mouse lemurs (genus Microcebus) and, conversely, how phylogenetic and population genetic patterns in these small primates can reciprocally advance our understanding of Madagascar's prehuman environment. The degree to which human activity has impacted the natural plant communities of Madagascar is of critical and enduring interest. Today, the eastern rainforests are separated from the dry deciduous forests of the west by a large expanse of presumed anthropogenic grassland savanna, dominated by the Family Poaceae, that blankets most of the Central Highlands. Although there is firm consensus that anthropogenic activities have transformed the original vegetation through agricultural and pastoral practices, the degree to which closed-canopy forest extended from the east to the west remains debated. Phylogenetic and population genetic patterns in a five-species clade of mouse lemurs suggest that longitudinal dispersal across the island was readily achieved throughout the Pleistocene, apparently ending at ∼55 ka. By examining patterns of both inter-and intraspecific genetic diversity in mouse lemur species found in the eastern, western, and Central Highland zones, we conclude that the natural environment of the Central Highlands would have been mosaic, consisting of a matrix of wooded savanna that formed a transitional zone between the extremes of humid eastern and dry western forest types.phylogeography | climate change | speciation | deforestation | ddRAD

Mouse lemurs’ and degraded habitat

“…In addition, opportunistic fecal material sampling from capture studies combined with emergent meta-barcoding approaches will bring a better understanding of diet and parasite load (De Barba et al, 2014; Quéméré et al, 2013) in complement to arduous field observations. Finally, combined continuous field and genetic efforts (Hotaling et al, 2016; Louis Jr. & Lei, 2016; Yoder et al, 2016) will likely bring soon an accurate representation of species distribution and taxonomy necessary to study such ecological patterns at the genus scale. While our work focused on mouse lemurs, the second most speciose lemur genus, we stress that DF use should be studied across vertebrate species.…”

Evaluating methods to visualize patterns of genetic differentiation on a landscape

“…EEMS , on the other hand, is built to visualize patterns of genetic differentiation over shorter distances by fitting a continuous surface of estimated gene flow across the landscape. Both EEMS and SpaceMix are being used increasingly frequently in empirical studies (Montinaro et al., ; Richmond et al., ; Tsuda et al., ; Uren et al., ; Yoder et al., ), but there has been no comparison of the two methods to determine how they perform in situations where the underlying patterns of genetic differentiation poorly match their models, or how these situations appear in their visualizations. Here, we sought to determine how the two methods perform using simulated genetic data that represent a range of both short‐ and long‐distance migration scenarios with the goal of better understanding the strengths and limitations of each method.…”

A biogeographical perspective on the variation in mouse lemur density throughout Madagascar

“…Recent phylogenetic studies have redefined a number of populations as distinct species, increasing the number of extant mouse lemur species to 24 (Yoder et al. , , Olivieri et al. , Radespiel et al.…”