Phytoplankton assemblages in a complex system of interconnected reservoirs: the role of water transport in dispersal

Phytoplankton in a complex network of reservoirs for drinking water supply was sampled in the dry and flood seasons to understand the role of dispersal through hydrochory and of environmental filters in determining the phytoplankton abundance and composition. The main assumptions tested in the present study are that (i) phytoplankton structure in these waterbodies is strongly dependent on the transportation with the river waters flowing through them and (ii) the importance of this stochastic transportation is decreasing as the connectivity with the river decreases allowing environmental filters to shape phytoplankton structure. The multivariate analysis showed that although phytoplankton was inoculated largely by Pearl River water inputs and inflow among the system, the hydraulic architecture of the reservoir network shaped and modulated the composition and abundance of phytoplankton.