Comparing the effect of landscape context on vascular plant and bryophyte communities in a human-dominated landscape

Aims: It is important to understand the effect of landscape context on biological communities to predict how biodiversity will be affected on human-dominated land-scapes. While many studies have tested the effects of landscape context on the spe-cies richness and composition of vascular plants, few have compared the responses of vascular plants and bryophytes on the same landscape. We sampled non-epiphytic bryophytes and vascular plants in 184 plots to test whether three landscape context factors measured four years or four decades previously could predict bryophyte or vascular plant species richness and composition after accounting for local factors.Location: Temperate forests and oak savannahs, Vancouver Island, British Columbia, Canada.Methods: We used model selection and comparisons to test the effects of surround-ing road density, total amount of forest, and distance to the nearest forest edge on species richness, species richness of non-disturbance-associated species, and com-munity composition after controlling for important local predictors including sub-strate availability and topography.Results: The species richness of non-disturbance-associated vascular plants was lower in plots with greater surrounding historical road density, and perennial stayer bryophyte richness declined with increasing historical road density and lower histori-cal forest amount, suggesting a potential extinction debt. Landscape context signifi-cantly affected total species richness and community composition of vascular plants, but not bryophytes.Conclusion: While bryophytes appear to be less sensitive overall to landscape con-text than vascular plants, disturbance-intolerant perennial stayer bryophytes may decline in the future in response to the increased road density and loss of forest cover that has occurred over the past four decades.