Measurement of the Ecological Integrity of Cerrado Streams Using Biological Metrics and the Index of Habitat Integrity.

Deusiano Reis,Sheyla Couceiro,Ayala Salazar,Mayana Machado,Paula Morais

doi:10.3390/insects8010010

Deusiano Reis, Sheyla Couceiro + Show 3 more

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https://doi.org/10.3390/insects8010010

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Abstract

Generally, aquatic communities reflect the effects of anthropogenic changes such as deforestation or organic pollution. The Cerrado stands among the most threatened ecosystems by human activities in Brazil. In order to evaluate the ecological integrity of the streams in a preserved watershed in the Northern Cerrado biome corresponding to a mosaic of ecosystems in transition to the Amazonia biome in Brazil, biological metrics related to diversity, structure, and sensitivity of aquatic macroinvertebrates were calculated. Sampling included collections along stretches of 200 m of nine streams and measurements of abiotic variables (temperature, electrical conductivity, pH, total dissolved solids, dissolved oxygen, and discharge) and the Index of Habitat Integrity (HII). The values of the abiotic variables and the HII indicated that most of the streams have good ecological integrity, due to high oxygen levels and low concentrations of dissolved solids and electric conductivity. Two streams showed altered HII scores mainly related to small dams for recreational and domestic use, use of Cerrado natural pasture for cattle raising, and spot deforestation in bathing areas. However, this finding is not reflected in the biological metrics that were used. Considering all nine streams, only two showed satisfactory ecological quality (measured by Biological Monitoring Working Party (BMWP), total richness, and EPT (Ephemeroptera, Plecoptera, and Trichoptera) richness), only one of which had a low HII score. These results indicate that punctual measures of abiotic parameters do not reveal the long-term impacts of anthropic activities in these streams, including related fire management of pasture that annually alters the vegetation matrix and may act as a disturbance for the macroinvertebrate communities. Due to this, biomonitoring of low order streams in Cerrado ecosystems of the Northern Central Brazil by different biotic metrics and also physical attributes of the riparian zone such as HII is recommended for the monitoring and control of anthropic impacts on aquatic communities.

Highlights

Aquatic systems worldwide are being threatened by the expansion of human activities [1], mainly by agriculture, cattle ranching, and urbanization [2]
Site Taq8 was classified as an altered environment with a Habitat Integrity (HII) of 0.77, and environmental changes measured in this site refer mainly to changes due to partial removal of marginal vegetation, resulting in a pioneer herbaceous and shrub cover with frequent breaks due to cattle activity
Trichopterans and Odonata families show a positive response to physical aspects of the riparian zone, as measured by HII

Summary

Introduction

Aquatic systems worldwide are being threatened by the expansion of human activities [1], mainly by agriculture, cattle ranching, and urbanization [2]. With the exception of some remote Amazonian rivers, most aquatic environments have been altered by human activities in Brazil [4], including wetland drainage, dams, road building, and deforestation for human settlements and intensive agriculture. All of these modifications have a negative impact on the hydrology, vegetation cover, and terrestrial-aquatic linkages of the affected systems [5], but there is a shortage of studies focusing on the consequences of these impacts to ecosystem integrity in Cerrado and Amazonia watersheds

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Discussion

Conclusion