کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5741854 1617128 2017 9 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Original ArticlesMayfly bioindicator thresholds for several anthropogenic disturbances in neotropical savanna streams
موضوعات مرتبط
علوم زیستی و بیوفناوری علوم کشاورزی و بیولوژیک بوم شناسی، تکامل، رفتار و سامانه شناسی
پیش نمایش صفحه اول مقاله
Original ArticlesMayfly bioindicator thresholds for several anthropogenic disturbances in neotropical savanna streams
چکیده انگلیسی


- Twenty mayfly genera are bioindicators of different anthropogenic pressures.
- A multiple-taxa approach indicates the value of quantitative biological information for conserving and managing freshwater ecosystems.
- Benchmark water quality values in Brazilian Legislation are higher than the turnover threshold of several mayfly genera.
- Brazil will lose many sensitive genera even within the limits imposed by national environmental legislation.

Anthropogenic disturbances are widely recognized as major threats to terrestrial and aquatic biodiversity worldwide, including areas located in non-forest ecosystems. Headwater streams in the neotropical savanna are severely threatened by large-scale landscape changes that degrade local habitat characteristics and lead to biodiversity loss. The objective of our study was to evaluate Ephemeroptera assemblages as bioindicators of catchment land use and cover, local streambed and riparian vegetation conditions, and instream water quality. To do so, we sampled mayfly nymphs in 184 stream sites across a broad disturbance gradient in four hydrologic units of the Brazilian neotropical savanna. We selected seven metrics without significant co-variation with natural variability: % catchment urban, riparian vegetation condition index (RCOND), human disturbances of the stream channel and riparian zone (W1_HALL), substrate mean embeddedness (XEMBED), dissolved oxygen (mg L−1), pH, and total phosphorus (mg L−1). We ran threshold indicator taxa analysis (TITAN) for each disturbance metric to detect change points in mayfly genera responses (whether sensitive or tolerant) and assemblage turnover pattern. TITAN showed that 20 of the 39 genera found were robust bioindicators (based on purity and reliability values >0.95), sixteen of them being sensitive to increased disturbance. The most sensitive genera were Tricorythopsis (Leptohyphidae) and Camelobaetidius (Baetidae), showing decreased abundance to most disturbance metrics. We found a turnover pattern of mayfly genera in response to W1_HALL in a narrow variation range. For total phosphorus, the benchmark value defined in Brazilian Federal Legislation is higher than the turnover threshold of several mayfly genera. This indicates that we will lose many sensitive genera even within the limits imposed by national environmental legislation. The indicator taxa approach, based on multiple taxa rather than univariate metrics or single indicator species, demonstrates the value of quantitative ecological information for conserving and managing freshwater ecosystems globally.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Ecological Indicators - Volume 74, March 2017, Pages 276-284
نویسندگان
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