Abstract
Successful plant invasions are hypothesised to be associated with close
environmental matching or species poor communities. However, positive
correlations between non-native abundance and native plant richness can
also arise due to habitat heterogeneity (defined here as variation in
abiotic and biotic conditions over space and time). We analysed survey
and palaeoecological data for macrophytes in lakes covering a gradient
of eutrophication and connectivity to partition the roles of
environmental matching, macrophyte diversity and habitat heterogeneity
in explaining abundance and invasibility of Elodea canadensis, a widely
distributed non-native macrophyte in Europe. There was no association
between invasibility and macrophyte species richness. Instead habitat
heterogeneity variously enabled the coexistence of native macrophytes
and E. canadensis in lake metacommunities over time. Invasion resistance
was associated with high native macrophyte cover and unfavourable
environmental conditions. We show how spatial and temporal scales can
determine the relationship between habitat heterogeneity and
invasibility in lake systems.