Refining stream ecosystem evaluation: A novel approach using the family ecological index (FEIS)

Abstract

The use of ecological indices based on benthic macroinvertebrate population for streams ecosystem quality assessment receives great attention. Streams in general have high variability characteristics; thus, using a single index used for the whole stream stretch renders less accurate readings. Therefore, this study was conducted to produce an ecological index using benthic macroinvertebrates as a bioindicator for a clean stream ecosystem. In this study, 42 recreational streams throughout Peninsular Malaysia were sampled and 663 units of water and benthic macroinvertebrates samples were analysed. Three phyla, 19 orders, 117 families and 55,410 macroinvertebrate individuals were recorded. Benthic macroinvertebrate data were analysed using existing indices such as Shannon Diversity Index (H’), biotic indices (BMWPTHAI and FBI) and WQI to analyse water quality. Canonical Correspondence Analysis (CCA) was used to evaluate the strength of water quality and physical habitat in determining benthic macroinvertebrate community structure. Next, Principal Component Analysis (PCA) was used to produce new weights. Based on the similarities and dissimilarities of each family in their ecological functions, the components were truncated into only three significant groups with respective weights and a new ecological index, namely Family Ecological Index for Streams (FEIS). From the FEIS values calculation, three scales which are 2.11 to 3.00 (first class: excellent ecosystem), 1.36 to 2.10 (second class: healthy ecosystem), and 0.00 to 1.35 (third class: moderately healthy ecosystem) were obtained. It is found that FEIS is capable of exhibiting variations in stream quality even within clean streams and able to detect early deterioration in streams which is highly useful for management stakeholders to manage recreational streams in Malaysia. The new data-driven approach in the development of FEIS in this study can be applied to other rivers and the difference in the weights determination as well as formulation obtained can be observed.