TY - JOUR T1 - Spatial population structure in a patchily distributed beetle JF - Molecular Ecology Y1 - 2001 A1 - Roslin, T. SP - 823 EP - 837 KW - allozymes KW - aphodius KW - gene flow KW - genetic differentiation KW - mitochondrial DNA KW - spatial population structure AB - The dynamics and evolution of populations will critically depend on their spatial structure.Hence, a recent emphasis on one particular type of structure—the metapopulation conceptof Levins—can only be justified by empirical assessment of spatial population structuresin a wide range of organisms. This paper focuses onAphodius fossor, a dung beetle specializedon cattle pastures. An agricultural database was used to locate nearly 50 000 localpopulationsofA. fossorin Finland. Several independent methods were then used to quantify key processesin this vast population system.Allozyme markers and mitochondrial DNA (mtDNA)sequences were applied to examine genetic differentiation of local populations and to deriveindirect estimates of gene flow. These estimates were compared to values expected on thebasis of direct observations of dispersing individuals and assessments of local effectivepopulation size. Molecular markers revealed striking genetic homogeneity inA. fossor.Differentiation was only evident in mtDNA haplotype frequencies between the isolatedÅland islands and the Finnish mainland. Thus, indirect estimates of gene flow agreed withdirect observations that local effective population size inA. fossoris large (hundreds ofindividuals), and that in each generation, a substantial fraction (approximately one-fifth) ofthe individuals move between populations. Large local population size, extreme haplotypediversity and a high regional incidence ofA. fossorall testify against recurrent populationturnover. Taken together, these results provide strong evidence that the whole mainlandpopulation ofA. fossoris better described as one large ‘patchy population’, with substantialmovement between relatively persistent local populations, than as a classical metapopulation. VL - 10 ER - TY - JOUR T1 - Distribution and abundance of dung beetles in fragmented landscapes JF - Oecologia Y1 - 2001 A1 - Roslin, T. A1 - Koivunen, A. SP - 69 EP - 77 KW - aphodius KW - APHODIUS SCARABAEIDAE KW - assemblage KW - COLEOPTERA KW - community KW - diversity KW - dynamics KW - europe mammals KW - habitat loss KW - metapopulation KW - patchy KW - population KW - resource utilization KW - serpentine KW - spatial population structure KW - stability AB - Related species utilising similar resources are often assumed to show similar spatial population structures and dynamics. This paper reports substantial ecological variation within a set of Aphodius dung beetles occurring in the same patchily distributed resource, livestock dung in pastures. We show how variation in habitat and resource selectivity, in the rate of movements between pastures, and in the distribution of local population sizes all contribute to interspecific differences in spatial population structures. Local dung beetle assemblages are compared between two landscapes with different densities of pastures. In one of the landscapes, we contrast the abundances and regional distributions of Aphodius before and after 15 years of rapid habitat loss. Different species show very dissimilar responses to changes in the structure of the landscape. Our results suggest that generalist Aphodius species, and specialist species with high dispersal powers, occur as large "patchy" populations in the landscape. In contrast? a strict pasture specialist species with limited dispersal powers (A. pusillus) forms classical metapopulations. At the community level, interspecific differences in spatial population structures make the local community composition a function of the structure of the surrounding landscape. VL - 127 UR - ://000167629200008 N1 - digital & hard copy copy ER -