The Impacts Of Urbanization And Wetland Degradation

The Impacts of Urbanization And

Wetland Degradation

A case study of Tangla Town, Udalguri, BTAD, Assam

April 14, 2023 Archana Das 2

Introduction:Wetlands are called as “Biological Kidneys” and Ponds are the most diverse freshwater habitats and have been recently found to support more species, as well as more uncommon, rare, and threatened species compared to lakes, rivers, and streams.

In the heart of Tangla town, about 600 meters from the Public bus stop towards north, there was a pair of very large sized pond which were about 200 years old. Both the ponds were of equal size with an area of about 150 x 200 m2

each. Such ponds always illustrate a small functional ecosystem that is easy to understand. Both of these ponds were a place where different plants and animals that were adapted to aquatic environment. They were also a self -sufficient and self regulating system in the ecosystem of Tangla as both the ponds never dried out in years of drought or in every dry season.


The rising human population is driving the expansion of urban areas and this has inevitably resulted in habitat destruction. In late 2013, the owner of this pond decided to demolish one of the pond by filling earth. Once the earth filling was completed, the plot obtained was released for sell. By the end of late 2014 the entire plot had been sold.

At the present scenario habitat fragmentation has been another serious problem to the urban areas. Habitat fragmentation is the transformation of a large and continuous habitat into many smaller, isolated habitats. The expansion of cities causes the fragmentation of large areas of natural habitat through the construction of roads, houses and industry. Biodiversity is greatly reduced when large areas of natural habitat are fragmented or degraded.


Objectives:

As more and more people populate the Earth and as more and more land is taken over by humans, many natural areas including wetlands are destroyed, degraded, or reduced in size. Human activities such as wetland degradation have brought serious problems to our ecosystem. The demolishing of the pond at Tangla town in the recent year has been another such human activity which may harmfully affect our environment. Considering the above mentioned issues, the objective of this present study has been:1) To find out if the different species communities are affected due to degradation of the pond.

2) To find out if there is any impact of pollution due to destruction of the said pond.

3) To find out any adverse changes in the climatic factors of this area.


Methodology:

The paper is based on primary data collected through a case study carried out in Ward No 4 of Tangla town under Bhergaon Sub-division of Udalguri district.

Secondary information has been collected from different published literature.


The present study was conducted in

Tangla. Tangla town under

Bhergaon sub-division in Udalguri district of Assam is situated in North-Eastern India. Its

geographical location is 26° 34' 28.53" N 91° 58'

32.42"E.

The Pond Was Here

Study Area


In 2013 In 2015

View of the site in Google Map

The Pond in 2013 (left) & in 2015 (right)


Field Work Details:

Methods employed in this study involved a number of field based activities, which were undertaken in order to generate the necessary data. Initial desk study involved an assessment of the changes in the climatic factors such as temperature and humidity. During the study importance was given on the different land-use in order to assess land use changes and possible attendant impacts of human activities on the ecosystem of the locality. In addition, soil samples from the buffer zones were collected for testing pH, soil texture and water holding capacity as the pond was demolished by earth filling. A study was also conducted to check if there was any pollution hazard after demolishing the pond. During the study importance was given to observe the population of various organisms in that area with special reference to impact on the food chain and their effects. The study was conducted during Nov, 2014 to Feb, 2015.


Analysis of the study:

During the study sample of the soil was collected from 3 (three) different buffer zones of the demolished pond and were taken to the departmental laboratory of Zoology, Tangla College for testing its texture, water holding capacity and pH. Temperature of the site was recorded with thermometer in Celsius scale. We observed the site regularly and carefully for identifying various flora and fauna of the study site. Local people were also consulted to get some information.

Soil Quality:

Soil texture: The three samples collected mainly composed of soil finer than sand, but still feels gritty. Since the sample contains smaller ratios of sand and clay particles, the soil quality is slit.

Soil pH: After the laboratory test, the pH of the soil was found to be acidic with a pH of 5.5 But generally the soil pH at Tangla is around 4.5 to 5.

Water Holding Capacity: The ideal water holding capacity of slit soil is 72%. But during our study the water holding capacity of the soil in the site was found to be 65% .


Pollution Hazards:

The site has been used by some people as a place of dumping garbage including polythene and other non-biodegradable wastes.

There are a few motor vehicle garages nearby and mostly the garage mechanics are using the place for repairing the vehicles and also for vehicle washing.

Accumulation of different kinds of vehicle oil like diesel, engine oil, brake oil etc are seen very often.

Climatic Factors:

Due to degradation of the pond, the hydrology of the site is changed greatly. This has affected the relative humidity and temperature of the area up to certain extent.

The relative humidity of the study area including Tangla town is around 80% and average winter temperature is 11.40C

But during our study period the average temperature and relative humidity were found to be different.


Table 1: Showing the Soil Texture Soil pH and Water Holding Capacity of the soil sample

Sl No Month Max. Temp Min. Temp Avge Temp Humidity

1 Nov, 2014 21 0C 10 0C 15.5 0C 57%

2 Dec, 2014 16 0C 09 0C 12.5 0C 52%

3 Jan, 2015 16 0C 10 0C 13 0C 54%

4 Feb, 2015 17 0C 11 0C 14 0C 56%

Table 2: Showing the temperature of the site during the period of the study

Sample Soil Soil Texture Soil pH Water Holding Capacity

A 0.003 mm 6 70%

B 0.002 mm 5 60%

C 0.004 mm 5 60%

Average 0.003 mm 5.5 65%


Aquatic lives:

Wetlands are home to a diverse range of plants, birds, fish, frogs, insects and reptiles. Many birds were found to rely on degraded pond. These include waterfowls like ducks, geese and swans, grebes, egrets and herons. These birds are now never seen. The pond was the habitat of fish, frogs, snakes and mollusks. There were many hydrophytes in the pond. Aquatic plants can grow only in water or in soil that is permanently saturated with water. They are therefore a common component of wetlands. The common aquatic plants in the pond were water lily, duckweed, lotus, water hyacinth and algae. Due to loss of the pond, these organisms have also disappeared from the site.


Discussion: Degradation of the pond has resulted in alternation of soil quality. The

soil texture of the site has been changed from clay soil to slit soil with more percentage of sand. Soil texture affects the soil's ability to hold nutrients and water. Thus change of soil texture has affected the vegetation of a locality.

The pH of the soil also turned to acidic with a range of 5.5. Change of pH affects nutrients, minerals and growth of plants. It disturbs the burrowing animals too.

In the degraded pond we found that the water holding capacity of the soil is decreased to 65% instead of its normal value 72%.

The site has been used by some people as a place of dumping garbage including polythene and other non-biodegradable wastes. Oil pollution has been another issue from the vehicle garages.


Discussion: The relative humidity of the locality is greatly affected. The relative

humidity of the study site including Tangla town is around 80% in average. But during the month of Nov, 2014 to Feb, 2015 the average humidity was recorded to be only 55%.

Most important issue has been the habitat loss. The pond had been the home for many flora and fauna for years. After the pond is demolished, those organisms have become homeless.

The food chain of the ecosystem has been affected and its adverse effect is seen. In absence of the fish and frog population, the mosquito population in the area has been increasing significantly and the people are getting attacked by malaria.

The snake population is also affected due to the loss of the pond and snakes are found everywhere in the locality during summer and local people have reported to find the snakes even in their homes.


Suggestion:Wetland loss has been associated with the direct loss of species diversity due to destruction and lowered recruitment of infringing vegetation communities and displacement of fauna. The loss of wetlands may end with a loss of flora and fauna, which will affect the biodiversity. In order to protect our wetland following steps can be undertaken:

Habitat restoration is to be given importance as it is considered the alteration of an ecosystem back to its initial state.

Restoration practices should be undertaken for the species of wetland-breeding birds, aquatic medicinal plants etc.

Public perceptions of wetlands are important. So Government and NGOs should come forward for educating the common people in this field.

More research is needed on the interaction between wetlands & biodiversity.


Conclusion:

Wetlands are home to large numbers of both terrestrial and amphibious organisms and are often key areas during breeding seasons as representative species from across the food chain are collected in the soil and marshy land. Several variations of plant life exist only in wetlands and many varieties of migratory birds breed and rest in these fertile areas. In wetlands, small shellfish, crabs, and other aquatic life thrive and serve as food to land-dwelling animals. The loss of wetlands poses dangers to wildlife as well as human populations both in terms of protection of terrain and in a broader economic sense. Although efforts to stop the rapid loss of wetlands have been a relatively recent development, it is vital that efforts continue or problems already faced could be made much worse.


Reference:

Costanza R, et al. 1997. The value of the world’s ecosystem services and natural capital. Nature 387: 253-260.

Hong-yu, L. (2000). Landscape planning and ecology construction of wetland comprehensive protected area system in the Sanjiang Plain. Journal of Environmental Sciences, 12(3), 361.

McKinney, M. 2002. Urbanization, Biodiversity and conservation. Bioscience, 52, 883-890)

Paucharda, A., Aguayob, M., Peñaa, E., Urrutia, R. 2006. Multiple Effects of Urbanization on the Biodiversity of Developing Countries: The Case of a Fast-Growing Metropolitan Area (Concepción, Chile). Biological Conservation. 127, 272-281

Tiffany Wright and Jennifer Tomlinson, Oceans and Watersheds U.S. Environmental Protection Agency Washington, DC December 2006


Presented By:

Archana Das,Asst Professor, Zoology Dept,

Tangla College, Tangla.

Pranamika Goswami,

Asst Professor, Chemistry Dept,

Tangla College, Tangla.


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The Impacts Of Urbanization And Wetland Degradation

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