Conservation Genetics in Madagascar

Anthropogenic ecosystem change

I am currently investigating the origins and extent of Madagascar’s grasslands as part of the MADGRASS project. Field work will begin 1 March 2022 where genomic data will be used to estimate changes in population size over time in ecologically important grass species. I am excited to see how investigations of grasses can contribute to productive dialogs on land management and conservation policy. Similar analyses have been used to understand both anthropogenic and paleoclimatic effects on mouse lemur populations.

Figure 6 from Tiley, van Elst, et al. 2021 ¹ Analyses of population size change over time reveal crashes among mouse lemur populations that coincide with Pleistocene climate change near the Last Glacial Maximum (LGM). Anthropogenic effects are also observable, but populations were likely vulnerable and fragmented prior to human colonization of Madagascar.

Understanding how species form over short absolute timescales

Mouse lemurs are a species-rich group (relative for primates) that have diversified in a short amount of time. Many speciation events are likely associated with Quaternary climactic oscillations in Madagascar ². Mouse lemurs species are morphologically similar, which leads us to test ecological or behavioral hypotheses for their isolation and divergence.

Notably, mouse lemurs have impressively diversified vomeronasal repertoires ³. Although visually similar, the lemurs can likely sniff out their conspecifics.

Figure 6 from Hunnicutt, Tiley, et al. 2020 ³ ML topology showing multiple ancient duplication events leading to the origins of lemur V1R subfamilies and their subsequent expansions within mouse lemurs.

Madagascar is a ecologically complex place. There are transitions from wet forest to dry forest and an expansive savanna that has complex relationships with precipitation, fire and people that form macroniches, but river barriers, altitudinal limits, and disturbance that forms microniches too. Understanding the speciation and population genetic processes ¹ in mouse lemurs can also provide context or ecological and vegetative turnover. Future research aims to move from discovering patterns to testing mechanisms.