DNA metabarcoding reveals impact of local recruitment, dispersal, and hydroperiod on assembly of a zooplankton metacommunity

Understanding the environmental impact on the assembly of local
communities in relation to their spatial and temporal connectivity is
still a challenge in metacommunity ecology. This study aims to unravel
underlying metacommunity processes and environmental factors that result
in observed zooplankton communities. Unlike most metacommunity studies, we
jointly examine active and dormant zooplankton communities using a DNA
metabarcoding approach to overcome limitations of morphological species
identification. We applied two-fragment (COI and
18S) metabarcoding to monitor communities of 24 kettle holes over
a two-year period to unravel (I) spatial and temporal connectivity of the
communities, (II) environmental factors influencing local communities, and
(III) dominant underlying metacommunity processes in this system. We found
a strong separation of zooplankton communities from kettle holes of
different hydroperiods (degree of permanency) throughout the season, while
the community composition within single kettle holes did not differ
between years. Species richness was primarily dependent on pH and
permanency, while species diversity (Shannon Index) was influenced by
kettle hole location. Community composition was impacted by kettle hole
size and surrounding field crops. Environmental processes dominated
temporal and spatial processes. Sediment communities showed a different
composition compared to water samples but did not differ between ephemeral
and permanent kettle holes. Our results suggest that communities are
mainly structured by environmental filtering based on pH, kettle hole
size, surrounding field crops, and permanency. Environmental filtering
based on specific conditions in individual kettle holes seems to be the
dominant process in community assembly in the studied zooplankton
metacommunity.