Aquatic macrophyte community varies in urban reservoirs with different degrees of eutrophication

Suelen Cristina Alves Da Silva,Armando Carlos Cervi,Cleusa Bona,André Andrian Padial

doi:10.1590/s2179-975x2014000200004

Suelen Cristina Alves Da Silva, Armando Carlos Cervi + Show 2 more

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https://doi.org/10.1590/s2179-975x2014000200004

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Abstract

AIM: Investigate spatial and temporal variation in the aquatic macrophyte community in four urban reservoirs located in Curitiba metropolitan region, Brazil. We tested the hypothesis that aquatic macrophyte community differ among reservoirs with different degrees of eutrophication. METHODS: The reservoirs selected ranged from oligotrophic/mesotrophic to eutrophic. Sampling occurred in October 2011, January 2012 and June 2012. Twelve aquatic macrophytes stands were sampled at each reservoir. Species were identified and the relative abundance of aquatic macrophytes was estimated. Differences among reservoirs and over sampling periods were analyzed: i) through two‑way ANOVAs considering the stand extent (m) and the stand biodiversity - species richness, evenness, Shannon-Wiener index and beta diversity (species variation along the aquatic macrophyte stand); and ii) through PERMANOVA considering species composition. Indicator species that were characteristic for each reservoir were also identified. RESULTS: The aquatic macrophyte stand extent varied among reservoirs and over sampling periods. Species richness showed only temporal variation. On the other hand, evenness and Shannon-Wiener index varied only among reservoirs. The beta diversity of macrophyte stands did not vary among reservoirs or over time, meaning that species variability among aquatic macrophyte stands was independent of the stand extent and reservoir eutrophication. Community composition depended on the reservoir and sampling period. CONCLUSIONS: Our results support our initial expectation that reservoirs of different degrees of eutrophication have different aquatic macrophyte communities. As a consequence, each reservoir had particular indicator species. Therefore, monitoring and management efforts must be offered for each reservoir individually.

Highlights

Aquatic macrophytes play a central structuring role in aquatic ecosystems, forming a heterogeneous and complex habitat that determines the abundance and biodiversity of aquatic flora and fauna (Thomaz and Bini, 2003)
Variation in aquatic plant community indicate the sources of variation in organic matter of aquatic ecosystems (Pedralli, 2003), given that this community is considered the main source of organic matter in lentic ecosystems (Wetzel, 2001)
Even within the same geographical region, reservoirs with different degrees of eutrophication may be quite variable in aquatic plant communities

Summary

Introduction

Aquatic macrophytes play a central structuring role in aquatic ecosystems, forming a heterogeneous and complex habitat that determines the abundance and biodiversity of aquatic flora and fauna (Thomaz and Bini, 2003). Restoration and biodiversity promotion is a major focus of managers (Moreno and Callisto, 2006), highlighting the importance of studies on determinants of aquatic macrophyte composition. Understanding how aquatic macrophyte communities vary in urban reservoirs is central to support management actions and conservation in such degraded ecosystems. A general trend is that a progressive eutrophication in aquatic systems, especially in urban reservoirs, provides abundance occurrence of aquatic macrophyte (Pedralli, 2003). The community of aquatic macrophyte varies between habitats and over time depending on local environmental conditions (Lacoul and Freedman, 2006; Thomaz et al, 2009; Padial et al, 2009). Describing how aquatic macrophytes vary spatially and temporally in urban reservoirs is of outmost importance. One of the big gaps in studies on aquatic macrophyte in the Neotropics is the lack of research addressing the testing of ecological hypotheses (Padial et al, 2008)

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