Spatial variability of aquatic plant and microfaunal seed and egg bank communities within a forested floodplain system of a temperate Australian river

Abstract

Aquatic plant and microfaunal propagule banks represent a major source of regenerative potential in river-floodplain ecosystems. This study investigated the spatial patterns of microfaunal and aquatic plant propagule bank communities within a wetland complex on the forested floodplain of a temperate Australian river system that had recently been completely inundated and dried again. Microfaunal emergence and aquatic plant germination were examined at the wetland complex spatial scale by incubating sediment samples collected from ten sites, randomly distributed within a 30 km2 area of floodplain. Spatial (northing, easting and elevation) and environmental variables [commence-to-flow (CTF), %clay, %silt and %moisture] were also examined at each site to assist in describing the spatial patterns of the propagule banks across the floodplain. It was predicted that the microfaunal and aquatic plant propagule bank communities would be homogeneously distributed at the wetland complex scale in response to the recent widespread flooding. In contrast to our prediction, microfaunal and plant propagule bank communities varied among most sites, with this variation best explained by location (northing) and elevation (which was related to site CTF). This suggests that microfaunal and plant propagule bank communities are heterogeneously distributed in forested floodplain systems, even following widespread flooding events.