Classic metapopulations are rare among common beetle species from a naturally fragmented landscape
Driscoll, DA and Kirkpatrick, JB and McQuillan, PB and Bonham, KJ, Classic metapopulations are rare among common beetle species from a naturally fragmented landscape, Journal of Animal Ecology, 79, (1) pp. 294-303. ISSN 0021-8790 (2010) [Refereed Article]
1. The general importance of metacommunity and metapopulation theories is poorly understood
because few studies have examined responses of the suite of species that occupy the same fragmented
landscape. In this study, we examined the importance of spatial ecological theories using a
large-scale, naturally fragmented landscape.
2. We measured the occurrence and abundance of 44 common beetle species in 31 natural rainforest
fragments in Tasmania, Australia. We tested for an effect on beetle distribution of geographic
variables (patch area, patch isolation and amount of surrounding habitat) and of
environmental variables based on plant species, after first accounting for spatial autocorrelation
using principal coordinates of neighbourmatrices. The environmental variables described a productivity
gradient and a post-fire succession fromeucalypt-dominated forest to late-successional rainforest.
3. Few species had distributions consistent with a metapopulation. However, the amount of
surrounding habitat and patch isolation influenced the occurrence or abundance of 30% of beetle
species, implying that dispersal into or out of patches was an important process.
4. Three species showed a distribution that could arise by interactions with dominant competitors
or predators with higher occurrence in small patches.
5. Environmental effects were more commonly observed than spatial effects. Twenty-three per
cent of species showed evidence of habitat-driven, deterministic metapopulations. Furthermore,
almost half of the species were influenced by the plant succession or productivity gradient, including
effects at the within-patch, patch and regional scales. The beetle succession involved an increase
in the frequency of many species, and the addition of new species, with little evidence of species
turnover. Niche-related ecological theory such as the species-sorting metacommunity theory was
therefore the most broadly applicable concept.
6. We conclude that classic and source-sink metapopulations are probably rare in this large-scale,
naturally fragmented system, although dispersal processes like those occurring in metapopulations
may have a substantial influence on community composition. However, deterministic processes
(niche specialisation, species-sorting metacommunities and deterministic metapopulations) drive
the occurrence or frequency of the majority of species. We urge further research into the prevalence
of spatial ecological processes in large-scale natural ecosystems to expand our understanding of
the processes that may be important in nature.
adaptation, dispersal, limitation,edge effect, habitat fragmentation, habitat loss, insect, invertebrate, island biogeography; mass effects, neutral theory