Phytoplankton alpha diversity as an indicator of environmental changes in a neotropical floodplain |
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| Institution: | 1. Núcleo de Pesquisas em Limnologia, Ictiologia e Aqüicultura, Universidade Estadual de Maringá—UEM, Av. Colombo, 5790, Bloco H-90, Sala 23, CEP 87020-900 Maringá, PR, Brazil;2. Universidade Federal do Pará, Laboratório de Ecologia, Rua Coronel José Porfírio, 2515, São Sebastião, CEP—68372-040 Altamira, PA, Brazil;3. Programa de Pós-graduação em Ecologia de Ambientes Aquáticos Continentais, Brazil;1. Bayworld Centre for Research & Education, 5 Riesling Road, Constantia 7806, Cape Town, South Africa;2. Marine Research Institute & Department of Oceanography, University of Cape Town, Private Bag X3, Rondebosch 7701, South Africa;3. Oceans and Coastal Research, Department of Environmental Affairs, Private Bag X4390, Cape Town 8000, South Africa;4. Plymouth Marine Laboratory, Prospect Place, West Hoe, Plymouth PL1 3DH, United Kingdom;1. Key Laboratory for Agricultural Soil and Water Engineering in Arid Area of Ministry of Education, Northwest A & F University, Yangling 712100, Shaanxi, PR China;2. Institute of Water Saving Agriculture in Arid regions of China, Northwest A & F University, Yangling 712100, Shaanxi, PR China;3. Department of Agricultural and Biological Engineering, Purdue University, West Lafayette, IN 47906, USA;1. Institute of Earth Sciences, Sturlugata 7, 101 Reykjavík, Iceland;2. Marine and Freshwater Research Institute, Skúlagata 4, 101 Reykjavik, Iceland;3. GET, CNRS/URM 5563-Université Paul Sabatier, 14 rue Edouard Belin, 31400, Toulouse, France;4. Earth Science, University College London, Gower Street, WC1E 6BT, United Kingdom;5. Icelandic Meteorological Office, Bústadavegur 7–9, 108 Reykjavik, Iceland;1. CAS Key Laboratory of Coastal Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research (YIC), Chinese Academy of Sciences (CAS), Shandong Key Laboratory of Coastal Environmental Processes, YICCAS, Yantai Shandong 264003, PR China;2. University of Chinese Academy of Sciences, Beijing 100049, PR China;3. Center for Ocean Mega-Science, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao 266071, PR China;4. School of Resources and Environmental Engineering, Ludong University, Yantai, Shandong 264025, PR China;1. Institute of Oceanography, Federal University of Rio Grande (FURG), Brazil;2. Department of Bioscience, Aarhus University, Denmark;1. Department of Soil and Water Sciences, University of Florida, Gainesville, 32611 FL, USA |
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| Abstract: | Habitat fragmentation, overexploitation of natural resources, the introduction of alien species and environmental degradation in aquatic environments are the main causes of reductions in aquatic biota diversity. Phytoplankton represent good ecological indicators because they are highly diverse and rapidly respond to a wide array of environmental disturbances. We investigated the interannual variation in alpha diversity of the phytoplankton community in lakes of an alluvial floodplain. We predicted that the phytoplankton diversity decreases over time in lakes and rivers subjected to human activities, whereas those biotopes in areas under pristine environmental conditions do not show a reduction in alpha diversity. Phytoplankton samples were taken quarterly over a period of eleven years (2000–2010), from ten localities associated with three large rivers, which showed different uses of the watershed. The time series of alpha diversity was analysed, to assess the temporal trend, in addition to their relationships with environmental factors. Phytoplankton alpha diversity in the Upper Paraná River floodplain ranged between 4 and 87 species and showed a mean of 30 (±16.5). Sites associated with the Paraná River showed a decline in diversity, which was associated with transparency, nitrogen and phosphorus forms. These results reflect a combination of seston retention by damming and an increase in the N:P ratio, which appears to negatively affect phytoplankton diversity. If temporal trends in environmental variation and the phytoplankton community remain, the future consequences for phytoplanktonic diversity in the Paraná subsystem will be severe, which might cause changes in the trophic structure and dynamics, and therefore in the functioning of environments, since this community is one of the main sources of energy for other trophic levels. |
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| Keywords: | Environmental indicator Anthropogenic impact Plankton Loss of species |
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