Concepts of Robustness and Ecosystem Health – with Case Studies from The Indian Context

Reservoirs and estuaries are two diverse types of aquatic ecosystems that have their own uniqueness. While artificial aquatic systems like reservoirs encompass hybrid characters of both lakes and streams, estuaries are considered as the most productive of all ecosystems. A detailed study of these ecosystems becomes essential to comprehend the health of such systems. Universal to any ecosystem is its ability to counter conditions of stress and this ability termed as robustness signifies the systems’ sustainability. Robustness is a good indicator of ecosystem health and is also dependent on the magnitude and type of inflicted stress. A comparative analysis of ecosystem health and robustness indicators of Bakreswar reservoir and Hooghly Matla Estuarine system is presented as case studies. Descriptive ecosystem indices are discussed in the current study including different network indicators. As a conclusion of this study, it has been observed that while the Bakreswar reservoir is moderately stable with a fairly robust and mature system, the Hooghly ecosystem is facing degradation. Ecological network indices revealed that variation in robustness values for both the systems is related more with the fish biomass perturbation scenario rather than the producer perturbation. This is confirmed by the various network indices used for analysis.

Keywords: Ecological Network Analysis, Ecopath with Ecosim, Food Web, Reservoir, Trophic Structure.