Spatial dissimilarities in plankton structure and function during flood pulses in a semi-arid floodplain wetland system

Abstract

Floodplain wetlands in semi-arid regions have intricate channel-floodplain networks with highly variable and unpredictable wet and dry phases related to changes in hydrology and geomorphology. We tested the hypothesis that the presence of different hydro-geomorphic habitats in those systems drives structural and functional differences in aquatic communities. To test this hypothesis, we examined the densities and species composition (structural variables), and primary productivity and respiration (functional variables) of plankton communities, and water chemistry in three spatially explicit channel, floodout and lagoon habitat types inundated by environmental water releases in the Macquarie Marshes, semi-arid Australia. Significant differences were recorded among the community-level structural and functional variables among the three habitats. Greater densities of phytoplankton, zooplankton and planktonic bacteria were observed in a hydrologically isolated floodplain lagoon. The lagoon habitat also had greater primary productivity of phytoplankton and planktonic respiration compared with the channel and floodout. Our results suggest that water release to meet environmental flow requirements can be an important driver of planktonic diversity and functional responses in semi-arid wetland systems by inundating diverse, hydro-geomorphically distinct habitats.

The Effect of Hydrological Connectivity on the Zooplankton Structure in Floodplain Lakes of a Regulated Large River (the Lower Vistula, Poland)

“…All pelagic organisms (both alive forms and resting eggs) could be dispersed from river to local communities so it is a very important process. However, local factors such as habitat heterogeneity, water quality, and community interactions can affect the survival and reproduction of individuals [4,13,21,58]. This issue can be explored by studying resting eggs in bottom sediments and interstitial waters.…”

“…There are two theories describing how the connection between a floodplain lake and a river affects the zooplankton community. Kobayashi et al [21] and Lemke et al [22] observed high zooplankton density in hydrologically isolated floodplain lakes. The inflow of river water to lakes connected with the main river channel can periodically destabilize their environmental conditions.…”

Evidence for regional aeolian transport of freshwater micrometazoans in arid regions

“…Evidence for regional aeolian transport emanate from these habitats when they are dry (Lee et al 2009;Baddock et al 2011). Our research question was: Can micrometazoans be dispersed via wind over regional scales (10 2 -10 5 km) and survive transport to colonize distant aquatic habitats?…”

The Role of Environmental Factors in the Formation of Zooplankton in Tributaries of Lake Ladoga (Russia)

“…Zooplankton of 20 lakes of Kejimkujik National Park (Canada) was strongly correlated with such factor as elevation, but not with the studied hydrochemical parameters (Bowman et al, 2014). Only the differences in hydrological and geomorphological conditions led to structural and functional differences in the planktonic communities of the semiarid Macquarie Marshes (Australia) (Kobayashi et al, 2015).…”