How the terrestrial landscape affects aquatic dispersal

Posted on June 19, 2017

How does the surrounding terrestrial landscape affect the dispersal of pond-dwelling organisms? Although some studies suggest that small aquatic crustaceans can disperse efficiently across a range of intervening environments, other work has pointed to dispersal limitation, especially over large distances.  Czech researchers examined the passive dispersal of microcrustaceans (cladocerans, copepods, and ostracods) by comparing communities in 42 pools in a largely forested area containing deep (up to 100m) and narrow rocky valleys. The study area measured 18 x 25 km. The pools were created in 1997-2004 for conservation purposes (to provide extra habitat for amphibians, invertebrates and aquatic plants), and microcrustacean populations were sampled in 2005-2006. Data analysis revealed that crustacean dispersal was affected more by landscape topography and the spatial clustering of pools than by pure geographical distance. It seemed that the ridged landscape and steep canyons created dispersal barriers, partly by channelling the movements of potential vectors such as waterfowl and mammals. In such environments, “valley distance” is a more meaningful measure of pond separation than beeline distance.

Reference: Juracˇka, P.J. et al.  2016.  A naturally heterogeneous landscape can effectively slow down the dispersal of aquatic microcrustaceans.  Oecologia 180, 785–796.