  The significant role of space in maintaining species coexistence and
determining community structure and function is well established. However,
community ecology studies have mainly focused on simple competition and
predation systems, and the relative impact of positive interspecific
interactions in shaping communities in a spatial context is not well
understood. Here we employ a spatially explicit metacommunity model to
investigate the effect of local dispersal on the structure and function of
communities in which species are linked through an interaction web comprising
mutualism, competition and exploitation. Our results show that function,
diversity and interspecific interactions of locally linked communities undergo
a phase transition with changes in the rate of species dispersal. We find that
low spatial interconnectedness favors the spontaneous emergence of strongly
mutualistic communities which are more stable but less productive and diverse.
On the other hand, high spatial interconnectedness promotes local biodiversity
at the expense of local stability and supports communities with a wide range of
interspecific interactions. We argue that investigations of the relationship
between spatial processes and the self-organization of complex interaction webs
are critical to understanding the geographic structure of interactions in real
landscapes.
