Data for: 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 landscapes. While many studies have tested the effects of
landscape context on the species 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 surrounding road density, total amount
of forest, and distance to the nearest forest edge on species richness,
species richness of non-disturbance-associated species, and community
composition after controlling for important local predictors including
substrate 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
historical forest amount, suggesting a potential extinction debt.
Landscape context significantly affected total species richness and
community composition of vascular plants, but not bryophytes. Conclusion:
While bryophytes appear to be less sensitive overall to landscape context
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.