Corridor quality affects net movement, size of dispersers, and population growth in experimental microcosms

Corridors are expected to increase species dispersal in fragmented
habitats. However, it remains unclear how the quality of corridors
influences the dispersal process, and how it interacts with corridor
length and width. Here we investigate these factors using a small-scale
laboratory system where we track the dispersal of the model organism
Collembola Folsomia candida. Using this system, we study the
effects of corridor length, width, and quality on the probability of
dispersal, net movement, body size of dispersers, and the rate of change
in population size after colonization. We show that corridor quality
positively affected dispersal probability, net movement, and the rate of
change in population size in colonised patches. Moreover, corridor quality
significantly affected the size of dispersers, with only larger
individuals dispersing through poor quality corridors. The length and
width of corridors affected both the rate at which populations increased
in colonised patches and the net number of individuals which dispersed,
suggesting that these physical properties may be important in maintaining
the flow of individuals in space. Our results thus suggest that corridor
quality can have an important role in determining not only the probability
of dispersal occurs but also the phenotypes of the individuals which
disperse, with concomitant effects on the net movement of individuals and
the rate of change in population size in the colonised patches.