| Environment and spatial distance determine species distribution, but analyses typically address distributional patterns while assuming the underlying causal processes. I tested the impact of three factors thought to be important causal processes for distribution: (1) environment, (2) spatial distances, and (3) species interactions. I used experimental, observational and statistical methods to examine the distribution Viola praemorsa, a rare species with a patchy distribution. I found strong impacts of environment and space, but no direct impact from other species. At the broad scale, environment and space were important with evidence for niche specialization and suitable unoccupied habitat due to dispersal limitation. At the fine scale, environment was the most important factor, but there was no evidence for specialization due to the lack of spatial structure to the environment. My work confirms the importance of environment and space, but shows that their impact varies by spatial scale. |
