Population genetics as a tool for measuring connectivity in tropical plants – a case study from South American mountains

Agnes Dellinger, Ovidiu Paun, Diana Margot Fernandez-Fernandez, Darin S. Penneys, Jürg Schönenberger

Habitat loss and fragmentation are known to affect species both locally and across their entire distribution range, hindering genetic interchange between populations and possibly leading to population isolation and subsequent extinction. Plants, which themselves are sessile organisms, depend on vectors for pollen or seed dispersal to achieve population connectivity. Experimental studies suggest that birds and bats are more efficient pollinators than bees, particularly in tropical mountains as they transfer larger amounts of pollen and are capable of spanning larger distances between plant individuals. In several tropical plant groups, shifts from bee pollination in lowland species to vertebrate pollination ((humming)birds, bats) in montane species seem to be common as the activity of vertebrates is less affected by adverse weather conditions prevalent in mountains. It remains, however, largely unknown if these different pollinators affect population genetic diversity and population connectivity in different ways.
We chose the Neotropical tribe Merianieae (Melastomataceae), harbouring bee, hummingbird/bat and passerine pollination, as a model system to study consequences of pollinator shifts on mating systems and population genetic diversity. All selected species were self-compatible, regardless of pollinator type. No signs of pollen limitation were found in the vertebrate pollinated systems and the lowland bee-pollinated system. Comparing two bee pollinated populations at different altitudes, however, showed strong pollen limitation in the high altitude population. Our population genetic results further support the idea that vertebrate pollinators are better at linking populations over large geographic distances, with higher levels of observed heterozygosity and higher population genetic diversity among populations than in bee pollinated species.

Department of Botany and Biodiversity Research
External organisation(s)
California Academy of Sciences
No. of pages
Publication date
Austrian Fields of Science 2012
106042 Systematic botany, 106008 Botany, 106012 Evolutionary research
Portal url