Tidal flats can be found on most of the world's coastlines and are
particularly vulnerable to anthropogenic disturbances. They are
important transient ecosystems between terrestrial and marine ecosystems
and their biodiversity provides important ecosystem services. Owed to
their unique position between the terrestrial and the marine realm,
strong environmental gradients of elevation, sediment composition but
also food availability are prevailing. Here we investigate which
environmental factors drive the spatial and temporal patterns in
macrozoobenthos abundance, biomass, richness, diversity and species
composition on back barrier tidal flats in the East-Frisian Wadden Sea.
We found that with increasing mud content the total abundance of
organisms in the sediment significantly increased, while biodiversity
and biomass were not changing significantly with increasing mud content.
Biomass of macrozoobenthos decreased with higher elevation towards the
salt marsh. In contrast to expectations, increasing Chl a availability
as a measure of primary productivity did not enhance biomass or
abundance, but was associated with significantly reduced species
richness. Species composition varied significantly among and within
islands due to variation in sediment composition, resource availability
and human-induced disturbance. In conclusion, macrozoobenthos biomass,
abundance and biodiversity is interrelated in a complex way with the
physical, abiotic and biotic processes in and above the sediment.
Negative impacts of primary production on macrozoobenthos species
richness demonstrate possible negative effects of nutrient inputs in
tidal flat areas and the need for cross-boundary protection.