Mining in Odisha – A Necessary Evil

Orissa’s lungs are gradually shrinking as extensive mining continues in different parts of the state. A report published in June 2021 revealed that nearly 57000 hectares of forest land was diverted in Orissa for non-forestry purposes, and 18,500,000 trees were cut down between 2010 and 2020.

Mining involves extracting of useful materials from the earth through primarily two processes – underground mining and surface mining. If done properly and safely while keeping the environmental impact in mind, mining can irrefutably help to boost a region’s economy.

Orissa’s mines have a direct impact on India’s economy and global trade. Steel output in India is expected to increase by a huge amount before 2031, contributing roughly 2.1 percent to the country’s Gross Domestic Product (GDP), and it is expected to exceed three percent in the next decade, thanks to Orissa mines. Other minerals from Orissa’s mines, aside from iron and steel, have the potential to completely reshape India’s economy.

But the other side of the coin cannot be neglected. Mining destroys the surrounding landscape, forestry, and pollutes rivers and lakes.

It also leads to a type of pollution known as ‘acid mine drainage’, which occurs when the sulphides formed due to mining dissolve in rainwater to produce acids, that drastically affects the aquatic plants and animals. Along with acid mine drainage, the disposal of mine waste can also cause severe water pollution from toxic metals. The toxic metals commonly found in mine waste, such as arsenic and mercury, are harmful to the health of people and wildlife if they are released into nearby streams. Excessive mining results in sinkholes, erosion, loss of biodiversity, and contamination of groundwater, streams, lakes, etc. Mining in Orissa has significantly affected the health of hundreds of people with a surge in air pollution levels.

The Times of India had published a report stating that the “state government had earned a record revenue of more than 13,200 crore during the 2020-21 financial year, largely owed to the mining revenue. When the lockdown was implemented, the government had also named mining as one of the critical services, recognizing the sector’s importance.

Thus, in a place where mining holds immense significance, responsible mining is the only viable solution. Adhering to environmental norms could save the remaining, precious biodiversity of Orissa.

Reference:
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The plight of Ganga

India’s longest river – the Ganges – has been a reluctant name in the list of the world’s most polluted rivers. Originating from the western Himalayas, this astounding work of nature gushes downward, turns right, and begins its eastbound journey for the Bay of Bengal. Several tributaries like the Yamuna, the Gandak and the Ghaghara join the Ganga in its 2500-kilometer journey across northern India.

Image Source

Imagine a river with water as clear as water can be; with flourishing biodiversity and pollution a forgotten phenomenon. Sadly, the Ganga River is a painful contrast of this picture.

As noted by Mr. Y. Sharma in his case study published on behalf of the United Nations Environment Programme, the Water Supply & Sanitation Collaborative Council and the World Health Organization, the Ganga’s river basin spanning over 1 million square kilometers is home to 37 percent of India’s population. Significant for activities such as navigation, transportation and irrigation, the National River is a boon that we have misused.

Besides 37% of India’s population, several wildlife species (including India’s national aquatic animal, the Ganges River Dolphin) identify the Ganga River as their home. But with their home being destroyed precariously, survival has become a threatening challenge.

On a daily basis, nearly 3 billion liters of wastewater from sewage, domestic and industrial sources is dumped directly into the river. Among other things, the river has become a carrier of animal carcasses, human corpses and religious waste. Furthermore, the discharge of industrial effluents from tanneries in Kanpur or sugar mills in the Kosi, Ramganga and Kali river catchments into the Ganges has polluted it severely. The runoff of fertilizers and other chemicals into the river, defecation along its banks and large-scale bathing in the river have all contaminated the river. Massive deforestation along the banks of the river has also contributed to alarming decrease in rainfall.

Image Source

The irony is that our actions are harming us. With the quality of Ganga’s water being deteriorated adversely, a grave threat has been inflicted over human health with increased chances of contracting diseases like cholera, hepatitis or even diarrhea. In fact, the Ganges’ pollution kills more people than bomb blasts.

Make no mistake, however. The list of the victims of Ganga’s pollution includes thousands of animals too. Take the Ganga River Dolphin, India’s National Aquatic Animal, for instance. A collapsing species, these dolphins are one of the few freshwater dolphins in the world. And our activities are thrusting the already endangered species towards the brink of extinction.

The Ganges River Dolphin (Image Source)
Thousands of dead fish turn up on the banks of the Ganga (Image Source)

Numerous measures have been undertaken to right wrongs, but the Ganga River has not been restored to what it used to be earlier. The fact is that if we are responsible for pushing the Ganges to its miserable status quo, we can also be responsible for reversing this situation. There is always a sliver of hope for restoring the Ganges which the Environmentalist Foundation of India seeks to foster.

Majuli Island of the Brahmaputra River in Assam: Origin and alteration in geomorphological features

by Rohan Nath

Introduction 

The mighty Brahmaputra River in Assam is home to the largest river island of the world,  Majuli Island which spans an area of 1255 km2(Fig 1, 2). The island is a subdivision of the  Jorhat district of Assam and is inhabited by around 153,000 people. “Vaisnavite” shrines,  popularly known as “Sattras” is present on this island which led it to become a principal  pilgrimage site for the last 400 years. However, flooding and severe bank erosion harm the  island at this current time. 

Fig. 1. Location of Majuli Island. (1917).  

Image Source: Sarma, J. N., & Phukan, M. K. (2004). Origin and some geomorphological  changes of Majuli Island of the Brahmaputra River in Assam,  India. Geomorphology, 60(1-2), 1-19.

Three important rivers bound the island, namely, the Subansiri River, Kherkutia Suti in the  north, and the Brahmaputra River in the south.  

The Majuli island is characterized by a spindle shape lying in NE-SW direction with an  altitude of 85.9m above sea level. Numerous lowlands and swamps of various shapes and  sizes occupy the plain topography with low relief. Few big rivers and several small streams  flow through the island. Alluvial fine loamy soils dominate the Majuli. The subtropical  monsoon climate brings an annual rainfall between 1494 to 2552 mm.

Fig. 2. Majuli Island of the Brahmaputra River. 

Image Source: https://timesofindia.indiatimes.com/travel/destinations/majulithe-worlds largest-river-island-might-just-disappear-in-the-future/as64012861.cms

There is a high mean annual flow and suspended sediment load of the Brahmaputra and  Subansiri (Table 1). 

Table 1. The mean annual flow and suspended sediment load of the Brahmaputra and  Subansiri. 

Year River Mean Annual Flow Annual Suspended Sediment Load
1975-1990 Brahmaputra 8829.5 m3/s 402 million metric tons during 1955- 1979
1956-1982 Subansiri 1671 m3/s 35.48 million tons annually

The mighty Brahmaputra leads to s severe bank erosion, which threatens the existence of  Majuli. 

The origin of Majuli 

According to historical surveys and reports, Majuli stretched between a location named  Banfang or Lakhu in the west and Bengmora in the east. In ancient histories of Assam, it had  been referred to as ‘Majali’ or a piece of land located in between two adjacent and parallel  rivers because the land was situated between the Luhit (Brahmaputra) in the north and its  tributary, the Dihing (Burhi Dihing) in the south.

The Brahmaputra River (formerly known as the Luhit or Luit) flowed to the north of the land  area of Majuli. The Dihing (one of the tributaries of the Brahmaputra) flowed south of Majuli  and met the Brahmaputra at Lakhu (Fig. 3). The land area of Majuli was converted into an  island when the Brahmaputra shifted its course southward and united with the Dihing near the  confluence point at Dihingmukh which is located around 190 km east of Lakhu, the former  confluence point. The southward shift of the Brahmaputra is believed to occur between 1661- 1696 due to a series of frequent floods and earthquakes.  

Fig. 3. The flow course of the Brahmaputra and the Dihing rivers before the  formation of Majuli. Image Source: Sarma, J. N., & Phukan, M. K. (2004). Origin and  some geomorphological changes of Majuli Island of the Brahmaputra River in Assam,  India. Geomorphology, 60(1-2), 1-19.

Following the formation of the Majuli island, the Brahmaputra was divided into two separate  branches. 

i. Luhit Suti or Kherkutia Suti – Brahmaputra (Luhit) flow to the north of Majuli. ii. Burhi Suti – The flow of Brahmaputra was directed to the south of Majuli through  the channel of the Dihing tributary. 

There was a natural event of channel shift when the major flow of the Brahmaputra was  diverted from the Kherkutia Suti into the Dihing leading to the enlargement of the channel (Fig. 4). 

Fig. 4. The flow course of the Brahmaputra and the Dihing rivers during the  formation of Majuli. Image Source: Sarma, J. N., & Phukan, M. K. (2004). Origin and  some geomorphological changes of Majuli Island of the Brahmaputra River in Assam,  India. Geomorphology, 60(1-2), 1-19.

Current scenario 

Currently, the Brahmaputra River resulted in an erosion in the southern boundary of the  Majuli island with a faster erosion in the southwestern part of the island. There has been a  noticeable increase in erosion during 1917-2001. The channel of Brahmaputra has widened  due to the erosion of both of its banks. The great Assam earthquake of 1950, further leads to  landslides in the eastern Himalayas which resulted in an increased flow of sediments into the  river. The high amount of sediment descended the plains, choked the channel of the river  which caused channel widening due to bank erosion. It has been reported that the width of the  Brahmaputra channel has increased up to 300% since 1917.  

The thick sand layer beneath the topsoil is undermined by the water which caused an increase  in erosion. The erosion is slower in locations where there is a presence of cohesive silty-clay  beds at the base of the banks.  

The Government of Assam is actively involved in assessing damage to agricultural land due  to sand deposition, the loss of property and life due to floods, and land area depletion due to  erosion, leading to the displacement of settlements and families from their location.  Therefore, it is an urgent need for the government to look upon it due to socioeconomic  issues associated with it. 

Reference 

1. Sarma, J. N., & Phukan, M. K. (2004). Origin and some geomorphological changes of  Majuli Island of the Brahmaputra River in Assam, India. Geomorphology, 60(1-2), 1- 19. 

Dying a Slow Death – Lakes of Tamil Nadu

Lakes form an important part of an ecosystem. They help sustain the aqua-life as well as their surrounding habitat, and provide us with water for both domestic and industrial purposes. Lakes also help in regulating the flow of rivers.

In Tamil Nadu, lakes are one of the most important pillars required for agriculture and irrigation. They supply most of the water for the growth of common crops. But our underestimation of the vitality of these rich water resources has led to a dreadful result – a revelation made by a news article published in February 2021 informed the public of the disappearance of thousand lakes and tanks in the last five decades. This is just an estimate. There may be a plethora of reasons behind this, though one major and often unheeded one is the excessive irrigational pressure put on Tamil Nadu’s lakes.

Farmers tend to use surplus water for cultivation than the standard requirements. In addition to these, they heavily depend on pesticides and insecticides to maximize production and increase their profits each agricultural year. The chemicals used either seep into the soil and contaminate the groundwater reserves, or flow down into the lakes, causing water pollution.

The Pulicat lake, situated about 50 kilometers north of Chennai, is gradually choking to extinction, as water-intensive cultivation and industrial expansion continue to push the lake to the brink of its existence. Extensive irrigation also makes room for silting, that drastically supplements the danger faced by the aquatic life.

An article published a few years ago had reported that the silting process diminishes the depth of the lake. Many fish species that survive in the water body usually prefer deeper waters, any due to this, the population of twelve to fifteen species of fish declined at an alarming rate.

We need to implement expeditious measures to protect the precious lakes of Tamil Nadu. Laws and regulations aren’t enough, we need to act on them and work towards our goal. Lets save Tamil Nadu’s lakes!

An acidic threat to aquatic organisms

Acid rain is the one of the quintessential phenomena that portrays the negative outcomes of human activity and can occur in the form of rain, snow, sleet or fog. Though some rain can be naturally acidic, our activities are making it worse.

What causes acid rain?

When compounds like sulfur dioxide and nitrogen oxides are released into the atmosphere, they travel upwards and react with water, oxygen and other chemicals to form sulfuric and nitric acids. These acids then mix with water and other materials and fall down as ‘acid rain’.

Acid rain may be caused by natural sources. For instance, small proportions of sulfur dioxides and nitrogen oxides are emitted into the atmosphere by volcanoes. The resultant rain from these compounds is mildly acidic in nature. When such rain falls to the ground, alkaline materials present in streams, lakes, soils, etc. neutralize it and prevent it from causing any harm.

What happens when the rain becomes more acidic? Will nature be able to neutralize strongly acidic rains? Sadly, the answer is no. Natural neutralization sources can’t handle acidity levels beyond their capacity. Thus, these sources may even be washed away by acid rain, thereby perilously breaking the fine balance in nature.

What makes mildly acidic rain more acidic?

Though acid rain can be caused naturally, humans are the main reason behind it. Our activities release enormous quantities of pollutants such as sulfur dioxide and nitrogen oxides in the air. The rain formed by these compounds is too acidic for it to be neutralized naturally.

What are the human sources that release dangerous quantities of pollutants?

There are enumerable ways by which humans have become causative agents of acid precipitation. Generation of electricity using fossil fuels like coal, for instance, emits the majority of sulfur dioxide and a quarter of nitrogen oxides present in the atmosphere. Factories, industries and refineries that use fossil fuels for combustion are also to blame. Vehicles like cars, buses and trucks are responsible for over half of nitrogen oxides present in the air.

Do water bodies get affected by acid rain?

The short answer is yes, they do. The adverse effects of acid rain are seen clearly in aquatic habitats such as lakes, ponds or rivers. Organisms in these water bodies survive within a specific pH range. When acidic rainwater drains into these water bodies, their pH levels reduce and they become more acidic. What does this mean for aquatic organisms?  

Some organisms may tolerate lower pH levels; some may not. But the more acidic these water bodies get, the greater is the imbalance in various food chains as certain animals start disappearing. Moreover, if acidity levels rise, fish eggs will not be able to hatch and populations of species may plummet dangerously.

Aquatic plants also suffer due to acidic habitats. Unable to withstand declining pH levels, many of these plants succumb to acid rain. 

Acid rain is one of the many consequences of rising pollution in the cities of India. Humans are harmed by it on the one hand. On the other hand, unfortunately, various other members of the environment have to suffer because of us. Recognizing this, the government has taken several measures to curb emissions. Yet, a promising future cannot be seen if each of us doesn’t start correcting fallacious actions and working towards a better environment.

Lake restoration through ‘Bioremediation’

71% of the earth’s surface is covered in water but less than 2% is portable fresh water. Yet, the contamination of essential freshwater sources like lakes and rivers has elevated over the years.

A wetland can be considered polluted or eutrophic when its ability to metabolize and convert nutrients is failing under the weight of nutrient overloading. Weeds and algae take over, lake-bottom muck builds and the body is filled with untreated harmful toxins.

Water Pollution Stock Photos and Images - 123RF
Source – https://emerging-europe.com/

Now the question is how do we bring a eutrophic body back to life? The answer is- Restoration and Rejuvenation. This method includes structural and land treatment measures, interception of nutrients and sediments, lake deepening or dredging, Dilution/Flushing, Aeration of Water, and much more

Photo showing the contrast of the lake basin before and after restoration.  | Download Scientific Diagram
Source – https://vertexaquaticsolutions.com/

Among the many restoration techniques is Bioremediation. It is a branch of biotechnology that employs the use of living organisms, like microbes and bacteria, in detoxifying contaminants, pollutants and toxins from water, soil and other environments. In simpler terms, certain microbes convert pollutants into small amounts of water or harmless gases like CO2.

In the process of Bioremediation, mainly aerobic bacteria like Pseudomonas , Alcaligenes and mycobacterium are used. They are known to degrade pesticides and hydrocarbons. Methanotrophs, which are also a type of aerobic bacteria, help utilize methane for carbon and energy. The bacteria combined with ideal environmental conditions like temperature and oxygen content are responsible for an effective decontamination of water.

Mycobacterium fortuitum - Wikipedia
Mycobacterium fortuitum , Source – https://en.wikipedia.org/

Some major advantages of ‘Bioremediation’ are:

  1. No side effects as the process is completely natural
  2. Minimal equipment required and time saving
  3. Cost effective/Economical
  4. Little energy required compared to other processes
Download Recycling Symbol - The Original Recycle Logo | Recycle logo, Recycle  symbol, Recycle sign
Source – pinterest.com

This natural rejuvenation technique is used all around the world to disinfect ground water, cleanse the area around oil spills and nourish the soil. The Indian government should use Bioremediation for detoxifying our contaminated wetlands and borewells,

Chennai – A Haven for Migratory Birds

by Rahul J

Our seasonal guests, from over 29 countries, come to India every year during the winter. [1] For most of us, a day’s long flight is enough to tire and bore us down. But for these birds, taking flight paths that can go over 1000kms long is not a choice, it is an act of survival. And as ecologists, we have all wondered how, and in particular, why- birds choose specific locations to migrate to, and that is what I’ll cover in this blog.

Why do they migrate?

Firstly, it is important to recognize that certain bird species can live and prosper only in certain conditions that their species consider ideal (similar to most wildlife). For instance, an arctic tern travels over 30,000 kilometers in its round-trip journey and moves from the arctic circle to the Antarctic circle. It is not a bird that resides in the equatorial region. [2] And when a certain region becomes unfavorable due to a season, it migrates to another more favorable region for breeding, food, and shelter. Hence it is an adaptation mechanism that we identify in them and the health of ecosystems can also be judged based on this metric.

Arctic Tern Source- Ebird

Why are they important?

Migrant birds play an especially important role in enriching the ecosystems that they cross and settle in. For starters, they act as pest controls in the areas they reside in, by eating insects that might harm crops and even prevent locust attacks which have been known to occur in seasons with reduced migration.

Bird droppings on the other hand are rich in nitrogen and act as fertilizers. Finally, they have a deep-rooted ecological impact and the absence of any one of the species can negatively disturb the food chain in multiple areas.

Why are the wetlands in Chennai especially important?

If we look at where Chennai is located, we can see that it is a coastal city, and the proximity to sea is very important for birds and gives security over lake conditions ( alkalinity/acidity )and food.

Moreover, Chennai being a metro-city, one of the advantages is the lack of poaching, compared to rural areas where awareness over ecological issues is very less and to top it all off certain wetland regions such as Pallikaranai are given the status of protected hotspots.

In the absence of the above reasons, the biggest deciding factor for birds to migrate to Chennai is simply the fact that they have multiple wetlands to choose from. Having been a large wetland city, even with considerable urbanization, Chennai has multiple pockets of areas where birds can settle down, such as — Pallikaranai, Adyar estuary, Muttukadu, Pulicat lake, Kelambakkam backwaters, etc.

Flamingoes Source- livechennai.com

But why is this choice very important? 

Birdwatchers and naturalists will know that birds love to come back to the same regions every year at a certain point in time, so even in the worst scenario when water levels seem to be too low in one wetland, having a choice to move somewhere close by is essential when you are travelling across continents to come to one specific area.

Birds also like to stop in multiple regions that are favourable to them in their round-trip for rest, and Chennai is a favourable location before they take off again to cross a longer flight path without other rest locations.

Wetlands here are also favourable in terms of weather conditions. Compared to severe winters abroad, and the western ghats which do not share the same climate as their neighbours, Chennai wetlands are milder and better for shelter and mating activities. 

Having said all of this, the focus then turns to sustaining these habitats so that our visitors have a nice stay.

Preservation of wetlands

To begin with, the bare minimum should be maintaining a clean environment for these species. This can be done by clearly demarcating waste areas, disposal sites and wetlands ( which are often used as dump yards, unfortunately ).

Then would be rejuvenating water bodies themselves, and increasing the green cover in them. For instance, croton plants are said to be an ideal plant for this activity.

At the end of the day, we need society to understand the importance of wetlands and be mindful, if not this burden rests disproportionately on the few who volunteer and take interest.

References
[1] https://www.downtoearth.org.in/blog/wildlife-biodiversity/how-important-are-migratory-birds-in-an-era-of-climate-change-75588
[2] https://oceanwide-expeditions.com/blog/22-enchanting-arctic-birds-and-their-most-fascinating-facts
[3] https://www.nationalgeographic.com/magazine/graphics/bird-migration-interactive-maps

Partitions and water

by Prithvi Saravanabawan

People say, “ If there is magic on this planet, it is contained in water”. Nevertheless, people being who they are, constantly think that they stand at the pinnacle of nature’s creation and naturally think that they are entitled to everything around us. This is an archetype that we have constructed for ourselves. This article does not aim at talking about how humans pollute or taint the water bodies. Instead, I aim at scrupulously yet briefly talking about different ways by which people strike water for its purpose. 

Firstly, the primary notion that aids this archetype exists in “ borders”. Though borders between different countries play an integral role in social and economic causes, they ostracize the very concept of human existence, sharing. Nonetheless, the concept of borders is not necessarily wicked or sinful. Therefore, I simply wish to enumerate that though the idea of borders is paramount in the domain of politics and economics, but nonexistent for rivers, lakes, or oceans.

Secondly, when we view this “borders” paradigm from an emotional perspective, we can observe that the root of this problem lies in a peculiar emotion. This emotion is greed. However, make no mistake, by greed I do not mean corporate greed, industrial greed, or economical greed. I mean the greed for improvement. This mortal emotion drives people to improve everything within a particular border of confined land we call countries, states, etc. Furthermore, in the process of making borders, people hoard water bodies like lakes and rivers in an attempt to improve their land or even deteriorate others. Thus creating a situation that produces an unbalanced environmental and ecological state within the same country. For example, altering the natural passage of a river may cause irreversible environmental damages like the extinction of indigenous marine life, endangerment of the various array of terrestrial animals that use that particular river as their primary source of water, and the plausible destruction of local flora.

In conclusion, I think it is safe to say that water breathes life into everything it touches. Though we are aware of this fact, our hubris shields us from attaining perfect harmony with the environment that surrounds us. I believe that our hubris as humans is the very source that instigates us to conceptualize improvement which makes way for borders. However, regardless of the veracity of the previous statement, it is an irrefutable fact that we cannot live without boundaries. Ergo, the best possible solution I could come up with for the topic “borders and water” is to establish good relationships with ourselves, our neighbors, and most importantly, our environment. 

Sustainable Living

by Nakshatra Balachander

Living Alone and Bored weekends?

Why don’t we move around our house and make it a zero-waste home without disposing anything?

A little background of zero-waste house concept: 

Zero Waste is a movement to reduce the amount one consumes and consequently  throws away. Adopting a Zero Waste lifestyle is one of the most sustainable ways of  living

Zero waste house is an idea to reuse those already existing bottles, old CDs and  various other household products into a décor item or to any other useful material.

How to shift to zero waste? (3 tips)

1.Monitor your everyday trash collection.

– Think about how you can cut them down or reuse them. Go around the house  and see if you can organise an area with the help of your inorganic solid waste  items. 

– Think of ways to regenerate greenery with the organic waste of your trash. If it  becomes impossible to use for regenerative purpose use them for  decomposition. Organic manures are in high demand because of its purity. So  why waste such a pure nature’s blessing?

2.When “Reusing” met “Creativity”. 

– When you find an object lying in the house and you’re already quite bored of it,  give it a new life by transforming it into another object. 

– This transformation can be of any form- colour, shape, feature or even usage. – One good example- We all have that one pen stand with a branding of any  company lying in the dust. Also, we all have some used gift wraps neatly folded  at home in the hope of using it again. Let’s give the stand that hopeless cover  to cover itself. With such good cover and shape it deserves to be on the dining  table as a spoon stand.

3.Converting villains to heroes. 

– We all have just started to adapt to zero waste. Which means there are some  plastic containers or bottles lying around. They’ve been a real villain and now  it’s time to transform them. 

– Let them be of a small help in helping an emerging life. With little holes in the  bottom, they can be an excellent plant holder or even bird feeder. – Usually, plants initially require a nursery sometimes to give out shoots. They  can be of help. 

– Well, sometimes those dried out paints can also be used again to decorate  these containers to give them a cute outlook.

With lockdowns we very often get bored to even watch series or movies. Why don’t  we spend our time just like we did in our school days in art classes?  

This one move can help lighten our mood and at the same time address the issue of  waste management. 

At this point of time, let’s not punish our environment anymore instead help them. 

Living a sustainable life is the need of the hour. Choosing to live sustainably can help  the environment become cleaner. If we don’t start bringing sustainability into our  daily lives, the future generations have to comprise their needs.  

All this can start with a little waste managing step.The pandemic is a great example to  know the damages that we’ve done to the environment and hence let’s be kind to  them by being waste free.

Ganges River Dolphins (Platanista gangetica gangetica): Effect of Dams and their Conservation

by Rohan Nath

Introduction

Considering the rate with which many landscapes, including freshwater ecosystems, around the world is being converted by humans; it is important to understand the evolutionary  potential of endangered species. The race between the surrounding countries to harness water  extraction and hydropower propels the South Asian Rivers into a threat. The most endangered  freshwater river dolphin in the world- the Ganges River dolphin (Fig. 1) is found in the  Ganges-Brahmaputra-Meghna and Karnaphuli River Basin (Fig. 2) in India, Nepal and  Bangladesh. However, several human development projects and activities like dams and  barrages as well as natural factors hamper the ecology of the Ganges dolphin and alter their  habitat. Numerous factors are likely to put the population of Ganges dolphin at risk of  destabilization and extinction.  

Dams and water-related projects in the main branch and the tributaries of the Ganges Brahmaputra-Meghna and Karnaphuli River Basin create a flow-regulating barrier that obstructs the movements of the dolphin population. This results in small, local  subpopulations that disrupt the potential of the dolphin population for evolution. 

Fig. 1. The Ganges river dolphin (Platanista gangetica gangetica).  Image Source: Mansur / WCS Bangladesh / Braulik et al., doi: 10.1111/mms.12801.

Fig. 2. The Ganges-Brahmaputra-Meghna and Karnaphuli River Basin in South Asia and  the location of the major dams that isolate the dolphin population into several small  groups. Image Source: Paudel, S., & Koprowski, J. L. (2020). Factors affecting the  persistence of endangered Ganges River dolphins (Platanista gangetica gangetica). Ecology and evolution, 10(6), 3138-3148.

Why is evolution important for the Ganges dolphin? 

Under the serious threats of extinction, the dolphin population needs to adapt to changing  environmental conditions which may threaten their existence. Therefore, evolution is the  mean by which the population can cope up with environmental stresses. 

Effects of Dams on the Population of Dolphins 

i. Modification of Physical Habitat  

The dams lead to habitat loss and fragmentation resulting in the isolation of small groups of  Ganges dolphin with limited geographic range. Disturbances in any hydrophysical habitats  like required depth can potentially reduce or eliminate the reproductive success of the Ganges  dolphin. Further research is necessary to identify the other hydrophysical habitats to increase  the conservation and survival of the dolphin population. The rate of local extinction has  increased in the upstream range of the Ganges River. Considering the high risk in these small  isolated populations, it is important to develop a plan to work on the conservation of these  endangered species. 

The government of India declared the Ganges dolphin as the national aquatic animal and  developed the Conservation Action Plan for the Ganges dolphin. However, the government  also constructed dams and structures at international borders leading to an alteration in the  Ganges-Brahmaputra-Meghna and Karnaphuli River Basin, risking the population of the  species they declared as the national aquatic animal.  

WCS dolphin conservation project in Bangladesh and Vikramshila Gangetic Dolphin  Sanctuary, Bhagalpur District of Bihar in India are some of the river dolphin-based  conservation projects.

ii. Genetic 

The Farakka Barrage in West Bengal divides the Ganges dolphin global population into  several local subpopulations. The geographical limitation of the subpopulation of the Ganges  dolphin puts them at a higher risk of extinction. This usually occurs through phenomena like  reduction of genetic variability and inbreeding depression that decreases the genetic diversity  and fitness of the population. The number of small local subpopulations is further increased  with an addition of a new dam. Considering that the extinction of species occurs quicker in  freshwater than in terrestrial ecosystem, the increase in inbreeding and decrease in genetic  heterozygosity makes the local extinctions of Ganges dolphin seem inevitable.  

iii. Behavioural ecology of the Ganges dolphin 

Anthropological influences are likely to affect the specialized circadian rhythm of the Ganges  dolphin concerning habitat selection like depth profile selection for foraging and  reproduction. This in turn can affect the life-history stages and functional ecology of these  species. The Ganges dolphin uses the cyclic range of water levels and seasonally moves  between the mainstream and tributaries. For example, the Ganges dolphin is stimulated to  migrate to other tributaries when there is a high-water flow in the mainstream. Anthropogenic  structures like hydropower dams or development structures can regulate the water level and  present as a false environmental cue, leading to a dysfunction of the functional ecological  behaviour of the dolphin.  

iv. Human-dolphin conflicts 

The primary cause of endangerment and extinction of the Ganges dolphins is due to their  interactions between artisanal fisheries in the Ganges-Brahmaputra-Meghna and Karnaphuli  River Basin. The endangerment of the Ganges dolphin can be attributed to the dietary and  diel activity and spatial and temporal overlap with the fisheries. The factors leading to the  fisheries and Ganges dolphin interaction needs to be assessed for effective management.  Therefore, the driving factors like spatial overlap, dietary competition and behavioural  distractions need to be further researched both qualitatively and quantitatively to manage the  coexistence between the river dolphin and fisheries.

v. Implications for future management 

Genetic tools cannot be applied to explore the viability of the Ganges dolphin population in  the Ganges-Brahmaputra-Meghna and Karnaphuli River Basin because of the limitation of  resources and conservative policies. It is essential to develop a regional intergovernmental  project that promotes the investigation of genetic viability and factors associated with the risk  of extinction using genetic-based research. For genetic monitoring, it is important to consider  the use of non-invasive tools, like environmental DNA. It is suggested to integrate census  data with genetic data for the accurate prediction in the population trend of the Ganges  dolphin. Proper capture and handling techniques might make it possible to improve the  genetic stability by translocation of individuals among subpopulations.  

It is tremendously difficult to predict the extinction using a single ecological factor due to the  synergistic effect of several other factors. A better understanding of management purposes  and conservation could be reached if we integrate demographics, genetics, and environmental  factors in future studies. Restoration and preservation of essential surfacing and foraging  habitats and maintenance of minimum stream flow can prevent the further decline in the  population of the Ganges dolphin.

Reference 

1. Paudel, S., & Koprowski, J. L. (2020). Factors affecting the persistence of endangered  Ganges River dolphins (Platanista gangetica gangetica). Ecology and evolution, 10(6),  3138-3148.