Environmental impact assessment and conservation planning of a Middle-Eastern River basin using a fish-based tolerance index
Citation:
Zare Shahraki, M., P. Fathi, E. Ebrahimi Dorche, J. Flotemersch, K. Blocksom, J. Stribling, AND A. Bruder. Environmental impact assessment and conservation planning of a Middle-Eastern River basin using a fish-based tolerance index. River Research and Applications. John Wiley & Sons Incorporated, New York, NY, 40(3):411-424, (2024). https://doi.org/10.1002/rra.4233
Impact/Purpose:
This study quantifying the sensitivity and tolerance of fish species to stressor gradients in the Karun River basin (Western Iran) and to used this information to develop a fish-based tolerance index, the Karun Fish Tolerance Index (KFTI), that can serve as a practical management tool. We also tested if native, endemic, and nonnative fish species differ in tolerance to the range of stressors that occur in the Karun River system. The KFTI complements a multimetric index (KFMMI) based on the same data developed in a companion study. The KFTI has the potential to provide a less complex yet robust, fish-based rapid assessment tool that can be used in studies where resources may be limited. Overall, while both the KFTI and the KFMMI provide important information about freshwater ecosystem health, they differ in their approach, scope, and level of detail, and are best used in combination to gain a more comprehensive understanding of ecosystem health and identify potential threats and stressors.
Description:
The tolerance of aquatic organisms to stressors is widely used to monitor and evaluate the condition of freshwater ecosystems. Tolerance values (TV) derived from analyses of the relationship between species and their environment are considered to be more objective than those that rely on expert opinion. We used principal component analysis (PCA) to derive a generalized stressor gradient based on physicochemical characteristics and physical habitat quality and structure. Scores of the first principal component axis (PC1) were used to estimate TV for 37 fish species collected from 54 sites in the Karun River basin, Iran. PCA of 17 variables identified stressors that were influential such as total phosphate, total nitrogen, total coliform, and habitat and morphological score. The species were separated into three categories on the stressor gradient: sensitive (18.9%), semi-tolerant (48.6%), and tolerant species (32.4%). Based on these results we developed the Karun Fish Tolerance Index (KFTI) and demonstrated that it performed well in separating the least, moderate, and most disturbed sites in the study area. The discrimination efficiency of the KFTI was 82.5%, which makes it a robust management tool for the protection and conservation of streams and rivers in the Karun River watershed. TV developed here reflect objective characteristics of the sensitivity of fish species to the predominant stressors in the Karun and similar systems.
URLs/Downloads:
DOI: Environmental impact assessment and conservation planning of a Middle-Eastern River basin using a fish-based tolerance index