Rivers, lakes, ponds and streams – natural freshwater ecosystems are a precious resource, not only because freshwater is limited, but also because of the rich biodiversity they support and the valuable ecosystem services they provide.
Freshwater ecosystems such as rivers in their pristine form are teeming with life and provide home to a variety of aquatic as well as terrestrial plants and animals that depend on each other and their surroundings for food and survival and maintain the ecological balance of the river.
Rivers provide important natural services to humans. River landscapes have served as areas for settlements and growth of civilisations since times immemorial. Besides provision of water for drinking and irrigation, and supply of fish as food and for supporting livelihoods, they help in regulation of climate and the water cycle; help in purification and waste treatment; regulation of erosion; storm and flood protection; soil formation and nutrient cycling; provide habitats for a range of plants and animals besides having recreational, cultural and aesthetic value.
However, freshwater ecosystems, their biodiversity, and the services they provide are being threatened by a range of anthropogenic (human-mediated) factors that include alteration of habitats, fragmentation, overexploitation as well as those due to introduction of invasive species, climate change, pollution etc.
Rivers in urban India
Rivers in urban areas in India are facing multiple stresses in form of sewage discharge, garbage dumping, encroachment, channelisation etc. All these stress factors severely affect the quality of water as well as natural functioning of the river leading to loss of habitat for a number of plant and animal species.
While these changes affect both, bigger animal species that are visible to the naked eye and the smaller/ microscopic ones that reside in the river waters, these effects are easily noticeable and can be studied in the case of birds and mammals through visual observations.
However, smaller animals like snails, aquatic insects and even microscopic ones such as rotifers are known to be equally or rather more affected by small changes in water quality such as temperature, Dissolved oxygen, nutrient concentrations. However, studies on these animals continue to be sparse due to the requirements of specific sampling techniques, laboratory infrastructure and taxonomic expertise .
Documenting biodiversity to save rivers
Many of these small/microscopic animal species living in the water are sensitive, responding to the changes in their local environments. They can be ‘indicative’ of the changes occurring in different local freshwater ecosystems. These thus have a high potential in monitoring the health of aquatic ecosystems.
Documentation of these animals and monitoring their responses to changes in water quality in the context of urbanisation can be extremely useful to devise management and/or conservation strategies for the urban water bodies. Infact, urban water bodies can potentially serve as a reserve of local biodiversity if they are carefully monitored and maintained.
The Mula Mutha, a river in dire straits in Pune
The Mula Mutha river in Pune, once a lifeline of the city is now in a dire state and has become a receptacle for solid waste, sewage, and encroachments. The life-supporting functions of the river are significantly reduced as it passes through Pune. While plans are being made by the Pune Municipal Corporation to revive the river, they continue to be hugely debated and vehemently opposed by citizens, environmentalists and developmental experts for their narrow and mechanistic approach of not looking at the river as a living ecosystem, but merely as a water source.
Jeevitnadi Living River Foundation has been at the forefront of giving a voice to the plight of the river through a number of citizen involvement and awareness activities and has started the ‘Adopt a river stretch program’ since 2017 to increase citizen awareness on the plight of the river and involve citizens in cleaning the river.
Freshwater invertebrate diversity in the river
As a part of the effort, a preliminary survey of 3 months was carried out at Mula and Mutha rivers in Pune to explore the freshwater invertebrate diversity. Mutha river stretch at Vitthalwadi and Mula-Ram river confluence stretch at Aundh-Baner link road were the two study locations and wetlands and rock pools along the river were studied during the survey.
This study revealed some very interesting findings:
As high as seventy species of freshwater invertebrates were identified along the 1 km long Mutha river stretch at Vitthalwadi, and sixty four species of freshwater invertebrates were found with high zooplankton diversity at the 1 km river stretch at Mula-Ram confluence. This shows the species richness at these urban waterbodies.
At Mula-Ram confluence, the team documented a new record of a freshwater gastropod (Pettancylus tenuis) for the Pune region and the findings published in the note titled 'First report of the freshwater gastropod Pettancylus tenuis (Bourguignat, 1862) (Gastropoda, Planorbidae) from Pune region, India' authored by Yugandhar Shinde, Shailaja Deshpande, Kirti Amritkar, Sameer Padhye and Chitra Vanjare in the journal Check List.
At Vitthalwadi, a freshwater rotifer from the genus Lecane (Nitzsch, 1827) was found for the first time from Maharashtra!.
Many a times, desilting of water bodies is carried out without consideration for many of these microscopic lifeforms that play an important role in maintaining the ecology of the river.This results in a drastic loss of biodiversity. These microscopic /small animals however form the base of the aquatic food chain and play a vital role in maintaining the ecological balance. Once disturbed, it becomes difficult to revive the ecosystem and establish them again in the ecosystem.
Studies such as these can be vital for future protection and conservation of waterbodies such as rivers.
Kirti Wani is the Founder Director, Jeevitnadi Living River Foundation, Pune, Maharashtra, India.
Dr Sameer Padhye is associated with Biologia Life Science LLP, Ahmednagar, Maharashtra, India.
The authors acknowledge Dr Chitra Vanjare, Dr Yugandhar Shinde, Dr Avinash Vanjare, Shailaja Deshpande and Aditi Deodhar in conceptualisation of the work, data collection and writing of the note. Authors also thank Adish Barve, Shubha Kulkarni, Sanjeev Naik, and Prashant Ingale for their help with the field work. Authors acknowledge Professor Hemant Ghate for providing the literature for identification of gastropods and Dr Shruti Paripatyadar for her help in the identification of aquatic bugs and beetles.