Influence of temporal changes on a diatom species in a floodplain lake: paleolimnological and biomonitoring approach

Abstract

Long term anthropogenic and natural impacts may result in effects on hydrological and environmental variables in aquatic ecosystems, as floodplain lakes, causing changes in diatom populations and community composition. We hypothesized that temporal abiotic factors over time favoured the establishment and increase in relative abundance of the Achnanthidium minutissimum complex. For a greater understanding of variation in species abundance, we used biomonitoring and paleolimnological data, combining 18 years of data from periphyton samples and more than 60 years from sediment samples. To test the relationships between the environmental parameters and relative abundance of A. minutissimum from biomonitoring data, we used generalized linear models (GLM). Based on GLM, the relative abundance of A. minutissimum increased with lower water depth, lower temperature, higher turbidity, and high pH. These conditions coincide with periods of drought in the floodplain, which were more frequent and longer after the construction of dams near Lake Garças. Additionally, the paleolimnological data suggest that climatic and anthropogenic influences on abiotic factors, such as water level and turbidity may have been responsible for the increased abundance of A. minutissimum in Lake Garças, as well as its dominance in the periphytic community from 2000, after the last dam construction near the lake. This shows how the modification of an aquatic environment can change diatom populations, and highlights the importance of combining historical information, paleolimnological analyses and biomonitoring data to understand population and ecosystem processes over time.

Keywords:

• dams
• Achnanthidium
• long-term monitoring
• hydrological regime
• wetland

Acknowledgements

We acknowledge the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES), for a doctoral scholarship granted for Daiane Trevisan Ruwer and Nicolli Cristina Osório, to the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) for the productivity grant to Liliana Rodrigues, to the Long Term Ecological Research (CNPq-PELD-Brazil), and to the Núcleo de Pesquisa em Limnologia, Ictiologia e Aquicultura (Nupélia) for technical and logistical support during the performance of this study. We also thank the Laboratory of Limnology of the Research Center in Limnology, Ichthyology, and Aquaculture of the State University of Maringá for analysis of environmental variables. We thank to the Poços de Caldas Laboratory - Gamma Radiometry Sector (National Nuclear Energy Commission, Brazil) for the geochronology analysis. We gratefully thank to José Flávio Macacini and Marcos Roberto Lopes do Nascimento for the help with geochronology analysis.

Disclosure statement

No potential conflict of interest was reported by the authors.

Supplemental data

Supplemental data for this article can be accessed at https://doi.org/10.1080/0269249X.2020.1848927.

Additional information

Funding

Doctoral and productivity scholarships granted from Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES), and Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), and research financiation of Long Term Ecological Research (CNPq-PELD-Brazil - processo n. 441260/2016-0).