Predicting productivity in tropical reservoirs: The roles of phytoplankton taxonomic and functional diversity

• Published in: Ecological indicators Vol. 48; pp. 428 - 435
• Main Authors: Santos, Ana M.C., Carneiro, Fernanda M., Cianciaruso, Marcus V.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-01-2015
• Subjects: Biodiversity; Biological diversity; Brazil; Chlorophyll-a; Ecosystem functioning; Ecosystems; Functional groups; Indicators; Linear mixed models; Productivity; Reservoirs; Species richness; Brazil; ASW, Brazil; FGRich_R; MFDDens; BEF; Chlorophyll-a; Linear mixed models; MFD; FR; Biodiversity; LMM; FEve; Simp_R; S; Simp_K; FGRich_K; Ecosystem functioning; FD; Simp; Functional groups; Species richness
• ISSN: 1470-160X; 1872-7034
• DOI: 10.1016/j.ecolind.2014.08.033

•We assess which diversity measures are good predictors of phytoplankton productivity.•Productivity and diversity present a positive relationship.•Functional group classifications are among the poorest predictors of productivity.•Species richness is the best indicator of phytoplankton productivity.
Primary productivity is intimately linked with biodiversity and ecosystem functioning. Much of what is known today about such relationship has been based on the manipulation of species richness. Other facets of biodiversity, such as functional diversity, have been neglected within this framework, particularly in freshwater systems. We assess the adequacy of different diversity measures, from species richness and evenness, to functional groups richness and functional diversity indices, to predict primary productivity in 19 tropical reservoirs of central Brazil, built to generate hydroelectric energy. We applied linear mixed models (and model selection based on the Akaike’s information criterion) to achieve our goal, using chlorophyll-a concentration as a surrogate for primary productivity. A total of 412 species were collected in this study. Overall we found a positive relation between productivity and diversity, with functional evenness representing the only exception. The most parsimonious models never included functional group classifications, with at least one continuous measure of functional diversity being present in many models. The best model included only species richness and explained 24.1% of variability in productivity. We therefore advise the use of species richness as an indicator of productivity in tropical freshwater environments. However, since the productivity–diversity relationship is known to be scale dependent, we recommend the use of continuous measures of functional diversity in future biodiversity and ecosystem functioning studies, in order to be certain that all functional differences between communities are being accounted for.