Phytoplankton alpha diversity as an indicator of environmental changes in a neotropical floodplain. (January 2015)

• Record Type: Journal Article
• Authors: Rodrigues, Luzia C.; Simões, Nadson R.; Bovo-Scomparin, Vania M.; Jati, Susicley; Santana, Natalia F.; Roberto, Maria C.; Train, Sueli
• Is Part Of: Ecological indicators. Volume 48(2015)
• Page Start: 334
• Page End: 341
• Publication Date: 2015-01
• Subjects: Environmental indicator -- Anthropogenic impact -- Plankton -- Loss of species; Environmental monitoring -- Periodicals; Environmental management -- Periodicals; Environmental impact analysis -- Periodicals; Environmental risk assessment -- Periodicals; Sustainable development -- Periodicals; 333.71405
• DOI: 10.1016/j.ecolind.2014.08.009
• Languages: English
• ISSNs: 1470-160X

Abstract

Highlights: Phytoplankton diversity decreased in areas subjected to greater human influence. Water transparency was negatively associated with phytoplankton diversity. Nitrate was negatively associated with phytoplankton diversity. Increase in the N:P ratio negatively affected the phytoplankton diversity. 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.