Ecological responses to flow variation inform river dolphin conservation

Abstract Many environmental flow (e-flow) studies and applications have predominantly used state—(i.e., at a single time point) and rate—(i.e., temporal change) based demographic characteristics of species representing lower trophic levels (e.g., fish communities) to build flow-ecology relationships...

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Autores principales:	Shambhu Paudel, John L. Koprowski, Usha Thakuri, Rajesh Sigdel, Ram Chandra Gautam
Formato:	article
Lenguaje:	EN
Publicado:	Nature Portfolio 2020
Materias:	Medicine R Science Q
Acceso en línea:	https://doaj.org/article/76e37664939443af8d09d0455c7b0652
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spelling	oai:doaj.org-article:76e37664939443af8d09d0455c7b06522021-12-02T13:34:01ZEcological responses to flow variation inform river dolphin conservation10.1038/s41598-020-79532-32045-2322https://doaj.org/article/76e37664939443af8d09d0455c7b06522020-12-01T00:00:00Zhttps://doi.org/10.1038/s41598-020-79532-3https://doaj.org/toc/2045-2322Abstract Many environmental flow (e-flow) studies and applications have predominantly used state—(i.e., at a single time point) and rate—(i.e., temporal change) based demographic characteristics of species representing lower trophic levels (e.g., fish communities) to build flow-ecology relationships, rather than using a process that incorporates population dynamics. Recent studies have revealed the importance of incorporating data on species traits when building flow-ecology relationships. The effects of flow on keystone megafauna species (i.e., body mass ≥ 30 kg) reverberate through entire food webs; however, the relationships between flow and these species are not well understood, limiting the scope of the relationships used in flow management. Here, we fill this gap by incorporating the habitat selection traits at different flows of a freshwater apex predator, Ganges River dolphin (GRD, Platanista gangetica gangetica), which plays a significant role in maintaining the structure, functions and integrity of the aquatic ecosystem. Using temporally and spatially measured GRD habitat selection traits, we quantified flow-ecology responses in the Karnali River of Nepal during the low-flow season when habitat was heavily reduced and water demand was highest. We define ecological responses as suitable habitat templates with enough usable surface area to support GRD fitness by improving reproduction and survival. We measured the available and occupied habitats to develop flow-ecology responses. Variation in flow resulted in substantial differences in the ecological response across time and space, suggesting that aquatic species adjusted in a variety of habitats to support their life histories and maintain viable populations. The limited availability of suitable habitats combined with uninformed water regulations by humans likely places GRDs under severe physiological stress during low-water seasons (i.e., January–April), suggesting that reduced flows contribute to the process of endangering and extirpating highly sensitive endemic aquatic biodiversity. Our study reveals that ad hoc or experience-based flow management is no longer tenable to maintain the integrity and functionality of aquatic ecosystems. We stress that quantifying the flow-ecology relationships of foundational species, particularly megafauna, in response to flow variation is crucial for monitoring the effects of water alterations and determining the minimum flows needed for maintaining healthy and functional freshwater ecosystems in the Anthropocene.Shambhu PaudelJohn L. KoprowskiUsha ThakuriRajesh SigdelRam Chandra GautamNature PortfolioarticleMedicineRScienceQENScientific Reports, Vol 10, Iss 1, Pp 1-13 (2020)
institution	DOAJ
collection	DOAJ
language	EN
topic	Medicine R Science Q
spellingShingle	Medicine R Science Q Shambhu Paudel John L. Koprowski Usha Thakuri Rajesh Sigdel Ram Chandra Gautam Ecological responses to flow variation inform river dolphin conservation
description	Abstract Many environmental flow (e-flow) studies and applications have predominantly used state—(i.e., at a single time point) and rate—(i.e., temporal change) based demographic characteristics of species representing lower trophic levels (e.g., fish communities) to build flow-ecology relationships, rather than using a process that incorporates population dynamics. Recent studies have revealed the importance of incorporating data on species traits when building flow-ecology relationships. The effects of flow on keystone megafauna species (i.e., body mass ≥ 30 kg) reverberate through entire food webs; however, the relationships between flow and these species are not well understood, limiting the scope of the relationships used in flow management. Here, we fill this gap by incorporating the habitat selection traits at different flows of a freshwater apex predator, Ganges River dolphin (GRD, Platanista gangetica gangetica), which plays a significant role in maintaining the structure, functions and integrity of the aquatic ecosystem. Using temporally and spatially measured GRD habitat selection traits, we quantified flow-ecology responses in the Karnali River of Nepal during the low-flow season when habitat was heavily reduced and water demand was highest. We define ecological responses as suitable habitat templates with enough usable surface area to support GRD fitness by improving reproduction and survival. We measured the available and occupied habitats to develop flow-ecology responses. Variation in flow resulted in substantial differences in the ecological response across time and space, suggesting that aquatic species adjusted in a variety of habitats to support their life histories and maintain viable populations. The limited availability of suitable habitats combined with uninformed water regulations by humans likely places GRDs under severe physiological stress during low-water seasons (i.e., January–April), suggesting that reduced flows contribute to the process of endangering and extirpating highly sensitive endemic aquatic biodiversity. Our study reveals that ad hoc or experience-based flow management is no longer tenable to maintain the integrity and functionality of aquatic ecosystems. We stress that quantifying the flow-ecology relationships of foundational species, particularly megafauna, in response to flow variation is crucial for monitoring the effects of water alterations and determining the minimum flows needed for maintaining healthy and functional freshwater ecosystems in the Anthropocene.
format	article
author	Shambhu Paudel John L. Koprowski Usha Thakuri Rajesh Sigdel Ram Chandra Gautam
author_facet	Shambhu Paudel John L. Koprowski Usha Thakuri Rajesh Sigdel Ram Chandra Gautam
author_sort	Shambhu Paudel
title	Ecological responses to flow variation inform river dolphin conservation
title_short	Ecological responses to flow variation inform river dolphin conservation
title_full	Ecological responses to flow variation inform river dolphin conservation
title_fullStr	Ecological responses to flow variation inform river dolphin conservation
title_full_unstemmed	Ecological responses to flow variation inform river dolphin conservation
title_sort	ecological responses to flow variation inform river dolphin conservation
publisher	Nature Portfolio
publishDate	2020
url	https://doaj.org/article/76e37664939443af8d09d0455c7b0652
work_keys_str_mv	AT shambhupaudel ecologicalresponsestoflowvariationinformriverdolphinconservation AT johnlkoprowski ecologicalresponsestoflowvariationinformriverdolphinconservation AT ushathakuri ecologicalresponsestoflowvariationinformriverdolphinconservation AT rajeshsigdel ecologicalresponsestoflowvariationinformriverdolphinconservation AT ramchandragautam ecologicalresponsestoflowvariationinformriverdolphinconservation
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Ecological responses to flow variation inform river dolphin conservation

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