Shallow Rocky Habitat of Brahmaputra River, Assam, India

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Environment

Affected by human activity

Affected by human activity

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Surrounding area

The surrounding area of the Brahmaputra River is characterized by diverse landscapes, encompassing mountains, valleys, plains, and wetlands. As the river flows through Tibet, India, and Bangladesh, it influences the geography and livelihoods of the regions it traverses.

In Tibet, the Brahmaputra starts its journey amidst the towering peaks of the Himalayas. The landscape is marked by rugged mountains, deep gorges, and pristine alpine meadows. Glaciers and snow-capped peaks feed the river, giving it a steady flow and adding to its grandeur.

As the river enters India, it meanders through the northeastern states of Arunachal Pradesh and Assam. Here, it creates vast floodplains and fertile valleys. The plains are interspersed with tea gardens, paddy fields, and grazing lands. The lush greenery, punctuated by small villages and towns, reflects the agrarian lifestyle of the region. The Brahmaputra’s influence is felt in every aspect of life, from agriculture to transportation.

The Brahmaputra’s floodplains, known as “Char” lands, are an important feature of the surrounding area. These lands are formed by the river’s annual floods, which deposit nutrient-rich silt, making them highly fertile. The Char lands are utilized for growing a variety of crops, including rice, jute, and vegetables. They also serve as grazing grounds for cattle and support diverse wildlife.

Further downstream, the river enters Bangladesh, where it merges with the Ganges and forms the expansive delta known as the Sundarbans. The Sundarbans is a UNESCO World Heritage Site and the world’s largest mangrove forest. It is an intricate maze of waterways, islands, and dense vegetation. The mangroves provide a unique ecosystem that supports a diverse range of plant and animal species, including the Royal Bengal Tiger, saltwater crocodiles, and numerous bird species.

The human settlements along the Brahmaputra River reflect the cultural diversity of the region. Indigenous communities, such as the Assamese, Mishing, and Bodo, have a deep connection to the river, relying on it for their livelihoods and cultural practices. The river is considered sacred by many communities, and numerous temples, monasteries, and shrines can be found along its banks, adding to the religious and spiritual significance of the area.

Overall, the surrounding area of the Brahmaputra River is characterized by its varied landscapes, from rugged mountains to fertile plains and vibrant wetlands. It sustains diverse ecosystems, supports agriculture and fishing communities, and holds cultural and ecological importance. The Brahmaputra River and its surrounding regions are a testimony to the harmonious coexistence of nature and human life.

Underwater landscape

The underwater landscape of the Brahmaputra River is dynamic and diverse, influenced by the river’s flow, sedimentation, and the surrounding terrain. While the exact details of the underwater landscape can vary at different locations and depths, several features can be observed.

One prominent characteristic of the Brahmaputra River’s underwater landscape is the presence of sandy and silty substrates. The river carries a substantial amount of sediment, especially during the monsoon season when it experiences high water flow. This sediment settles on the riverbed, creating sandy patches and sediment deposits. These areas provide habitats for various benthic organisms and act as feeding grounds for bottom-dwelling fish species.

The river’s current and flow patterns also shape the underwater landscape. The Brahmaputra is known for its strong currents, particularly in certain sections and during specific seasons. These currents can result in the formation of riffles, shallow areas with fast-flowing water, and deeper pools. The variations in water depth and velocity create microhabitats for different aquatic species.

Submerged vegetation, such as water hyacinth and aquatic grasses, can be found in certain parts of the Brahmaputra River but not at all region. These plants provide cover and food for various fish species and serve as nurseries for their young. Additionally, the submerged vegetation contributes to the overall ecological balance of the river ecosystem.

The Brahmaputra River’s underwater landscape is also characterized by rocky outcrops and boulders, sandy pebbles with algae rich in certain areas. These rocky features can create habitats with crevices and hiding places for fish and other aquatic organisms. They also contribute to the formation of riffles and provide structural complexity to the riverbed.

Underwater biodiversity in the Brahmaputra River includes various fish species, invertebrates, and plants that have adapted to the river’s unique conditions. Fish species such as catfish, mahseer, and carp can be found, utilizing the different habitats and food sources provided by the underwater landscape.

It’s important to note that the Brahmaputra River’s underwater landscape is subject to change due to natural processes like erosion, sedimentation, and seasonal fluctuations. The river’s complex interactions with the surrounding environment continually shape its underwater features, creating a dynamic and ever-evolving ecosystem.

Fish list:

• Tor putitora (Cyprinidae) – abundant
• Botia dario (Cobitidae) – many
• Trichogaster fasciata (Osphronemidae)– few (endangered species)
• Systomus sarana (Cyprinidae) – abundant
• Puntius terio (Cyprinidae) – many
• Microphis deocata (Syngnathidae) – many
• Dario dario (Badidae) – few
• Danio rerio (Cyprinidae) – few (endangered species)

Threats to ecology

The ecology of the Brahmaputra River and its surrounding areas faces several threats that impact the delicate balance of the ecosystem. These threats include:

Deforestation: Widespread deforestation in the river’s catchment areas, particularly in the Himalayan region, leads to soil erosion, increased sedimentation in the river, and loss of habitat for various plant and animal species. Deforestation also disrupts the natural water cycle, affecting water availability and contributing to ecological imbalances.

Pollution: Pollution from industrial activities, agricultural runoff, and domestic waste poses a significant threat to the river’s ecology. The discharge of untreated or poorly treated wastewater into the river leads to water contamination, harming aquatic life and affecting the overall water quality. Chemical pollutants can disrupt the reproductive systems of fish and other aquatic organisms.

Dams and water diversion: The construction of dams and water diversion projects on the Brahmaputra and its tributaries alters the natural flow of the river, impacting its ecology. These structures can obstruct fish migration, reduce sediment flow, and disrupt the natural flood pulse, which is essential for the river’s floodplain ecosystems.

Invasive species: The introduction of non-native species into the Brahmaputra River can disrupt native ecosystems. Invasive species, such as water hyacinth, negatively impact aquatic biodiversity by outcompeting native plants, reducing oxygen levels, and altering habitats.

Climate change: Climate change poses a significant threat to the Brahmaputra’s ecology. Rising temperatures, changing rainfall patterns, and increased frequency of extreme weather events can lead to altered river flows, flooding, and erosion. These changes can impact the distribution of plant and animal species, as well as the productivity of agricultural lands.

Overfishing: Unsustainable fishing practices, including overfishing and the use of destructive fishing methods, can deplete fish populations and disrupt the river’s food web. This can have cascading effects on the entire ecosystem and negatively impact the livelihoods of fishing communities.

Addressing these threats requires a holistic approach that focuses on conservation, sustainable land and water management practices, pollution control measures, and climate change mitigation strategies. Efforts to protect the ecology of the Brahmaputra River must involve cooperation among governments, local communities, and environmental organizations to ensure the long-term health and sustainability of this vital ecosystem.

Riparian zone

Trees near the aquatic habitat

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Bibliography

• → An Article on Different Indian Biotope by Kaushik Bose
  
• → Dario dario - Bengal dario, Scarlet badis
  
• → Brahmaputra River System
  
• → Scarlet Badis (Dario dario): A Hidden Gem of the Brahmaputra Basin by Gouranga Biswas, Banlam J. Marbaniang
  

Sitography

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