Drivers of Macrophyte and Diatom Diversity in a Shallow Hypertrophic Lake

Kateřina Šumberová,Martina Fabšičová,Jan Potužák,Ondřej Vild,Michal Ducháček,Markéta Fránková

doi:10.3390/w13111569

Abstract

We studied macrophyte and diatom assemblages and a range of environmental factors in the large hypertrophic Dehtář fishpond (Southern Bohemia, Czech Republic) over the course of several growing seasons. The spatial diversity of the environment was considered when collecting diatoms and water samples in three distinct parts of the fishpond, where automatic sensor stations continually measuring basic factors were established. Macrophytes were mapped in 30 segments of the fishpond littoral altogether. High species richness and spatiotemporal variability were found in assemblages of these groups of autotrophs. Water level fluctuations, caused by the interaction of fish farming management and climatic extremes, were identified as one of the most important factors shaping the structure and species composition of diatom and macrophyte assemblages. The distance of the sampling sites from large inflows reflected well the spatial variability within the fishpond, with important differences in duration of bottom drainage and exposure to disturbances in different parts of the fishpond. Disturbances caused by intensive wave action are most probably a crucial factor allowing the coexistence of species with different nutrient requirements under the hypertrophic conditions of the Dehtář fishpond. Due to a range of variables tested and climatic extremes encountered, our study may be considered as a basis for predictive model constructions in similar hypertrophic water bodies under a progressing climate change.

Highlights

Introduction iationsShallow lakes are often considered unique habitats of rich aquatic and wetland biota [1,2,3]
The values of total phosphorus (TP), chlorophyll-a concentrations, and water transparency (WT) correspond to hypertrophy
Babický stream bay (BSB) showed higher average concentrations of several nutrients (e.g., TP and total Fe) and usually lower water transparency than Dehtářský stream bay (DSB) and fishpond dam (FD); the highest measured chlorophyll-a concentrations were detected at FD, probably due to the cyanobacterial mats concentrated at this site because of wave action

Summary

Introduction

Introduction iationsShallow lakes are often considered unique habitats of rich aquatic and wetland biota [1,2,3]. Many are considered sites where a substantial part of biodiversity has already been lost and where mitigation measures are needed in order to turn back this unfavourable trend [1,8]. Many fishponds of these more than 20,000 artificial water bodies occurring in the Czech Republic, a country that lacks natural lakes, belong among aquatic habitats with the status of high eutrophy to hypertrophy [9]. Mainly in the Middle Ages [10], most of these fishponds have served for semi-intensive carp breeding and recently to a certain extent for other

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Discussion

Conclusion