TY - JOUR
T1 - Genetic insights into population recovery following experimental perturbation in a fragmented landscape
AU - Peakall, Rod
AU - Lindenmayer, David
PY - 2006/10
Y1 - 2006/10
N2 - We investigated the mechanism of population recovery in the Australian bush rat, Rattus fuscipes, following experimental perturbation in a fragmented landscape. Our study involved genetic monitoring over 24 months following the removal of animals from seven sites by intense trapping. A total of 171 bush rats was removed and statistical analysis confirmed a significant knockdown. At one site, local extinction followed the perturbation, while population sizes at 24 months varied from 37% to 90% of the original population size at the remaining sites. The outcomes of genetic analysis at 11 microsatellite loci and mtDNA indicated that population recovery was achieved predominantly by residual animals: recovery populations were genetically more similar to their respective pre-treatment population than near neighbours; assignment tests detected few immigrants; there was no influx of new immigrant alleles and haplotypes. This finding is consistent with emerging evidence for restricted gene flow in bush rats. The local extinction observed at one site indicate that, under severe perturbation restricted dispersal limits opportunities for, and the rate of, population recovery. Thus, while the bush rat appears resilient to substantial population size perturbation, once a critical minimum population size threshold has been reached, this species may be susceptible to local extinction. We concluded that some widespread species currently predicted to be extinction-resilient may, in fact, be at risk if localized extinctions occur and dispersal limitations prevent recolonisation.
AB - We investigated the mechanism of population recovery in the Australian bush rat, Rattus fuscipes, following experimental perturbation in a fragmented landscape. Our study involved genetic monitoring over 24 months following the removal of animals from seven sites by intense trapping. A total of 171 bush rats was removed and statistical analysis confirmed a significant knockdown. At one site, local extinction followed the perturbation, while population sizes at 24 months varied from 37% to 90% of the original population size at the remaining sites. The outcomes of genetic analysis at 11 microsatellite loci and mtDNA indicated that population recovery was achieved predominantly by residual animals: recovery populations were genetically more similar to their respective pre-treatment population than near neighbours; assignment tests detected few immigrants; there was no influx of new immigrant alleles and haplotypes. This finding is consistent with emerging evidence for restricted gene flow in bush rats. The local extinction observed at one site indicate that, under severe perturbation restricted dispersal limits opportunities for, and the rate of, population recovery. Thus, while the bush rat appears resilient to substantial population size perturbation, once a critical minimum population size threshold has been reached, this species may be susceptible to local extinction. We concluded that some widespread species currently predicted to be extinction-resilient may, in fact, be at risk if localized extinctions occur and dispersal limitations prevent recolonisation.
KW - Bush rat
KW - Dispersal
KW - Disturbance
KW - Habitat fragmentation
KW - Perturbation
KW - Population genetics
KW - Rattus fuscipes
UR - http://www.scopus.com/inward/record.url?scp=33748296230&partnerID=8YFLogxK
U2 - 10.1016/j.biocon.2006.05.013
DO - 10.1016/j.biocon.2006.05.013
M3 - Article
SN - 0006-3207
VL - 132
SP - 520
EP - 532
JO - Biological Conservation
JF - Biological Conservation
IS - 4
ER -