Changing foodwebs of Indian aquatic ecosystems under the threats of invasive species: An overview

Abstract

Biological invasions are a worldwide threat to the aquatic systems and have the potential to homogenize entire foodwebs and shift species abundance distributions to more skewed ones. Invasion impacts include effects on the foodweb structure and ecosystem functioning leading to a loss in native fish biodiversity and commercially important fisheries in many open water systems. The impacts of invasives are generally devastating as they spread in the foodweb with each species potentially interacting with multiple species. The foodweb modeling studies conducted in different inland aquatic ecosystems show that not all exotics cause a detrimental effect on the resilience of an ecosystem. Information on the foodweb structure and ecosystem properties is a prerequisite for formulating management protocols for conserving biodiversity, enhancement programmes and sustaining fisheries. The present paper reviews the impacts of invasive fishes in Indian aquatic ecosystems in the context of a changing foodweb scenario due to exotic fish species invasions. The information generated here could be applied for future research on similar ecosystems for deducing management actions.

Sustainable aquatic resource management and inland fisheries in tropical Asia: Interdisciplinary and transdisciplinary approaches

“…Exploitation patterns across trophic levels in aquatic food webs are highly unbalanced, as shown for Asian reservoir fisheries on the basis of mass-balanced models (e.g. Villanueva et al 2008 ; Panikkar et al 2021 ) and also for 110 different ecosystems worldwide (Kolding et al 2016 ). In accordance with the ecosystem approach to fisheries, a “balanced harvest” concept (BH) has been proposed, i.e.…”

Fisheries as ecosystem services: A case study of the Cauvery river basin, India

“…Fisheries play an important role in regulating the food web dynamics of the riverine and floodplain ecosystem (Khan et al, 2015;Panikkar et al, 2021). For example, in freshwater systems, the feeding behaviour of many adult and young fishes has cascading effects on population dynamics down the food web (Carpenter et al, 1985).…”

“…The feeding pattern of fishes can also influence the temporal availability of nutrients and the potential for algal blooms in nutrient-rich lakes, since fish mineralize nitrogen and phosphorus through excretion and defecation, thereby making these nutrients available for primary production (Schindler, 1992). As a result, knowledge of the foodweb structure and ecosystem features is required for developing management protocols for conserving biodiversity and maintaining the fish population (Sarkar et al, 2018;Panikkar et al, 2021).…”

“…The research on fisheries providing regulating services has not been recognized in terms of riverine ecosystem services research in India. However, some case studies indicated the importance of fish in regulating food web dynamics in the Cauvery basin (Khan et al, 2015;Panikkar et al, 2021). For example, the food web dynamics study of the Hemavathi reservoir focused on understanding the food-web structure and energy flow of fishes at different trophic levels (Khan et al, 2015).…”

“…For example, the food web dynamics study of the Hemavathi reservoir focused on understanding the food-web structure and energy flow of fishes at different trophic levels (Khan et al, 2015). When fed by other organisms, fish, including eggs, fry, and carcasses, serve as passive links between aquatic, aerial, and terrestrial ecosystems, contributing to other food webs (Panikkar et al, 2021). Food web models that explicitly consider energy flow from pelagic and benthic sources will provide a more realistic energy flow template for understanding the regulation of ecosystem functioning which has direct implications for river ecosystem sustainability and resilience (Vander Zanden and Vadeboncoeur, 2002).…”