Population Fragmentation and Genetic Variation in Grouse

Abstract: In this thesis the genetic variation of two grouse species, the Chinese grouse (Bonasa sewersowi) and the Black grouse (Tetrao tetrix) was examined with neutral genetic markers: microsatellites. Habitat fragmentation and isolation leads to structuring among and loss of genetic variation within populations.The Chinese grouse in a small population in Lianhuasan nature reserve was found to have undergone a population bottleneck and as a result of isolation and possible inbreeding showed genetic impoverishment hereof.The Black grouse populations in Europe face various different conditions from widely distributed areas of suitable habitat in the northern and eastern parts of its range to highly naturally and anthropogenically fragmented habitat landscapes in the west.Structure among populations was found in Great Britain where Wales, Scotland and England showed characteristics of three different genetic entities, indicating very little or no geneflow between these populations. The Dutch population showed signs of loss of genetic variation as to be expected from a population that has historically decreased in population size from several thousands to tens of individuals in a matter of decades. However the possibility to spot signs of a bottleneck was impaired due to the short time-window in which this can be observed in a population with such a low effective population size (NE).The sampled populations in Europe clustered into five different groups of genetic identities. The different clusters were: Great Britain-, the Netherlands-, Fenno-Scandian-, Alpine- and lowland German-Austrian populations. The level of genetic variation when compared over all these different populations decreased as a sign of isolation and small NE. However it was not feasible to separate the impact of these two factors.