A total of five INFRAGECO members presented talks outside the organized INFRAGECO symposium and all addressed important questions at the heart of the INFRAGECO project.
Lounès Chikhi presented the theoretical work done in collaboration with the team of Olivier Mazet, on the analysis of genomic data with models incorporating structure. He showed some preliminary results on three primate species, one mouse lemur and two orang-utans. He showed that their genomes indicate periods of habitat connectivity that increased and decreased through time. The title of his talk was “Demographic inference and model choice using the IICR (inverse instantaneous coalescence rate) as a summary of genomic diversity“.
Ute Radespiel presented results on small-scale molecular edge effects in one mouse lemur species, Microcebus ravelobensis, within a continuous forest site in the northwestern Madgascar. She showed that a sub-population at the forest edge was genetically less diverse and genetically differentiated from and only weakly connected to a core sub-population that was nearby and within the individual dispersal distance of this species. Results are concordant with a “local preference model” and such an effect, if confirmed in future studies, may contribute to a high vulnerability of fragmented populations. The title of her talk was “First signals of small-scale molecular edge effects in a non-human primate“.
Helena Teixeira, a PhD student of U. Radespiel, presented a talk on the use of genomic data from mouse lemur populations on the Montagne d’Ambre to reconstruct demographic changes back to the last glacial cycle. She used three different approaches and identified periods of population dynamics and changes in connectivity that coincide with climatic changes happening in northern Madagascar during those timescales. Her talk was entitled as “Reconstructing the demographic history of a nocturnal primate, Microcebus arnholdi, during the late Quaternary“
Frederik Kiene, another PhD student of U. Radespiel, presented the first part of his PhD project on the influence of forest fragmentation on the ectoparasites of small mammals and mouse lemurs. He found that ectoparasites and in particular temporary ectoparasites such as ticks and chigger mites suffer from forest fragmentation probably due to changed abiotic conditions in fragments and at forest edges. Reduced prevalences can still be observed over several hundred meters from the forest edge. His talk was entitled “Effects of habitat fragmentation on ectoparasite communities in mouse lemurs (Microcebus spp.) and small mammals in northwestern Madagascar“.
Guillaume Besnard gave a talk entitled “History of the savanna Malagasy olive tree (Noronhia lowryi)“. He presented a population genetic analysis of an endangered Malagasy olive of the Central Plateau savannas. A highly contrasting nuclear and plastid genetic structure was revealed suggesting that pollen-mediated gene flow allows panmixia, while seed-based dispersal may rarely exceed tens of meters. The crown age of N. lowryi maternal lineages was surprisingly old, back to ~6.2 Mya, apparently concordant with the global savanna expansion. A population bottleneck signature was finally revealed at ca. 350 generations ago, indicating a population collapse during the Late Quaternary. All together, these results highlight the unique value and vulnerability of the Malagasy savannas.
Adding to this, two INFRAGECO posters were presented at the ATBC meeting. They represented the Chikhi team, with a poster by Barbara Le Pors, entitled “Description of Microcebus tavaratra and M. arnholdi distribution in northern Madagascar with environmental and anthropogenic factors”; and another one by Emmanuel Rasolondraibe, entitled “Use of degraded habitats in Propithecus coronatus along the southern Mahavavy River (Antanimalandy and Antsoherikely), Madagascar“.