speaker: Rachael Adams
(University of Lethbridge, Alberta, Canada)
building: Dyers Brae
room: Seminar Room
see also: additional details
Understanding the influence of landscapes on the spatial distribution of genetic variation in species is necessary for their successful conservation and preservation. Physical barriers (e.g. mountains, geographic distance) often restrict population connectivity and dispersal causing a reduction in gene flow and the occurrence of genetically isolated populations. Dispersal barriers can also be non-physical (e.g. behaviour) and occur at smaller geographic scales (e.g. changes in vegetation).
Although birds have high dispersal potential, evidence suggests dispersal is restricted by barriers. One major concern lies with the increasing susceptibility of birds to changes in the environment through land use change and subsequent habitat fragmentation.
Assessment of the geographical area or landscape is therefore critical when measuring gene flow and making inferences about barriers, as cryptic barriers may exist. The black-capped chickadee (Poecile atricapillus) is a common, resident songbird to North America whose range encompasses a number of dispersal barriers.
Here, microsatellite markers were used to assess allelic variation and population differentiation in this species, and consequently, a reduction in gene flow is evident at both large and small geographical scales. Our sampling regime allowed us to test for breaks in the genetic structure and to determine whether the discontinuities identified correspond to changes in habitat, vegetation, physical barriers or other factors.