Temporal and environmental drivers of fish-community structure in tropical streams from two contrasting regions in India

Abstract

Environmental and anthropogenic factors are known to drive fish community structure in aquatic systems across the world. This study investigates fish assemblages in lower order streams across contrasting landscapes in central and eastern India. We documented the species diversity of these monsoon driven lower order streams in the two regions. We also investigated the potential common environmental drivers of richness and diversity and effect of season in these tropical streams. The study was based on seasonal data on abundance of fishes and environmental parameters collected between 2015-2017 from streams in states of Madhya Pradesh and West Bengal. Species diversity were compared across regions and seasons, based on their richness (SR) as well as diversity (Shannon index H'). Drivers of overall richness and diversity were analyzed using multiple linear regression methods, based on best subset selection. Analysis of data revealed high diversity in these streams in both regions. Cyprinidae, Bagridae and Channidae were the most dominant families in both regions. Despite the geographical and local ecological differences across the regions, common environmental parameters were found to influence richness and diversity across the two regions, indicating these as being key drivers of fish community structure. Water flow was a common factor driving both richness and diversity across both regions. Our study revealed a lack of seasonal effect in structuring fish communities in tropical streams. With stream and river ecosystems facing increasing threats due to habitat alterations and water quality degradation in countries such as India, a clear understanding of regional and local drivers of community structure of aquatic fauna is crucial. These results on the role of common environmental factors across ecoregions provides baseline information for understanding their ecological roles and developing management plans for important river basins and fish conservation in future.

Invasion meltdown and burgeoning threats of invasive fish species in inland waters of India in the era of climate change

“…The increasing patterns of invasive fish species in the Ganga river has been representing occupational patterns and changed distribution of fishery resources (Singh et al, 2013). Such rise in invasive species in the river has caused decline in the local fish catches and even change in biodiversity patterns (Singh et al, 2013;Kernan, 2015;Mondal and Bhat, 2020;Raj et al, 2021).…”

“…Invasive species might cause habitat modification, extinctions of endemic species, affect human health, and therefore endanger enormous economic costs (Singh and Lakra, 2011;Singh et al, 2013;Singh et al, 2014;Hanley and Michaela, 2019). In current time, unsustainable harvesting of natural stock of fishes especially from inland waters owing to invasion of introduced fish species led habitat degradation of riverine ecosystem and emerging conservation issues in the tropics, which has resulted in the stock decline of important local fish species, (Singh et al 2013;Panlasigui et al, 2018;Mondal and Bhat 2020). Climate variables, namely temperature, precipitation, and humidity may have significant long-term implications on water quality and fisheries with special reference to fish invasions (Auffhammer et al 2012;Jayaraman and Murari, 2014).…”

Ichthyofaunal diversity in snow-fed Mardi Stream of Gandaki River, Central Nepal

“…Freshwater fishes are known as the most threatened group of vertebrates (Reid et al 2013). Obtaining functional knowledge of the response of populations and communities to environmental variation and disturbance on a temporal and spatial scale is important in fish ecology (Blanchet et al 2014;Mondal and Bhat 2020). The environmental variables like water temperature, depth, water velocity, substrate, conductivity, alkalinity, dissolved oxygen, and pH play a significant role in shaping ichthyofaunal richness patterns and community structure (Tongnunui et al 2016;Kautza and Sullivan 2012;Akhi et al 2020;Limbu et al 2020).…”

Fish communities and associated habitat variables in the upper Subansiri River of Arunachal Pradesh, eastern Himalaya, India

“…Many studies correlating fish assemblages to habitat variables have been conducted in temperate as well as tropical regions across the world (Anderson et al 1995;Fausch & Bestgen 1997;Winston 1998;Guisan & Zimmermann 2000;May & Brown 2000;Horig & Fauscch 2002;Oakes et al 2005). In India, these studies have been done in the Western Ghats rivers (Saravanan et al 2003;Bhat 2004;Johnson & Arunachalam 2010), central Indian rivers (Johnson et al 2012;Shukla & Bhat 2017;Mondal & Bhat 2020), economically important fishes of the Ganga River (Lakra et al 2010), and rivers of the western Himalaya (Johal 2002;Sivakumar 2008;Atkore et al 2011;Johnson et al 2020).…”