Spatial Distribution of Plant-Associated Invertebrates and Environmental Bioassessment in a Natural Riverine Lake (Lake Fibreno, Central Italy)

Luciana Mastrantuono,Marcello Bazzanti,Valentina Di Vito

doi:10.4236/jwarp.2014.610087

Luciana Mastrantuono, Marcello Bazzanti + Show 1 more

Open Access

https://doi.org/10.4236/jwarp.2014.610087

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Abstract

Lake Fibreno is a Mediterranean riverine lake located in Central Italy and fed by large flows of groundwater and characterized by the presence of a wide reed stand area and of the only floating island of the South Europe. It is enclosed in a Natural Reserve recognized as Special Area of Conservation (SAC-IT6050015) for the presence of habitats and species (92/43/EEC) of relevant scientific interest. In this paper, we compare the plant-associated meio-macrobenthic invertebrates among sites with different environmental characteristics. Both vegetation and invertebrates of Lake Fibreno were well diversified and abundant and were composed of a mixing of species typical of lentic and lotic waters. Our results show that a gradient of orthophosphate and nitrite contents and current velocity appeared to be the driver factors affecting the flora and fauna spatial distribution at the sampling sites. To obtain a bioassessment of the ecological quality of the vegetation zone, we compared the riverine Lake Fibreno with typical lentic lakes previously studied in Central Italy. We selected metrics, such as macrophyte belt extent and taxa richness, invertebrate species richness and Shannon diversity, ETOM (Ephemeropta + Trichoptera + Odonata + Mollusca), ETOC (Ephemeropta + Trichoptera + Odonata + Coleoptera) and LCrM (Large Crustacea + Mollusca). The comparison indicated a good ecological status of the vegetation zone of Lake Fibreno mainly due to the continuous washout effects (dilution and fast water removal) which reduce the nutrient content available for phytoplankton and maintain the high transparency and good oxygenation of the lake waters.

Highlights

In most part of the world, the progressive deterioration of the freshwater ecosystems is dramatically increased in the last decades following to several anthropogenic activities, especially agricultural practices, urbanization and industrialization, but in these last years climatic changes and hydro-morphological modifications have represented additional negative pressures on the ecological integrity of the freshwater resources [1]-[3]
Our results indicate that the aquatic vegetation of Lake Fibreno appeared taxonomically diversified
Macrophyte assemblages clearly showed the presence of taxa typical of both stagnant and running waters [31], i.e. Lemna and Riccia are more typical of lentic waters, Callitriche spp. and Apium nodiflorum require cold and well oxygenated waters, and Sparganium erectum better characterizes lotic waters [36]

Summary

Introduction

In most part of the world, the progressive deterioration of the freshwater ecosystems is dramatically increased in the last decades following to several anthropogenic activities, especially agricultural practices, urbanization and industrialization, but in these last years climatic changes and hydro-morphological modifications have represented additional negative pressures on the ecological integrity of the freshwater resources [1]-[3] All these disturbances led to a taxonomic and functional monotony of the benthic community and became the primary causes of loss of biodiversity in freshwater ecosystems. The alterations of the lake shoreline, including reed stand destruction, can dramatically reduce the aquatic macrophyte biomass and taxonomic richness [6] This modification negatively affects the invertebrate community, as they use plants as substrate for feeding, refuge and reproduction [7]-[10]. Modifications caused by water quality changes determine a destabilization of the benthic community, involving loss of species richness and variations of the community structure and trophic chain [11]-[15]

Results

Discussion

Conclusion