Characteristics of Pond, Arid (Desert), Wetland Ecosystem in Nepal

Characteristics of Pond Ecosystem:

The group of organisms interacting among themselves and with their environment in the pond water is called pond ecosystem. A pond as a whole serves a good example of the freshwater ecosystem. A pond indeed exhibits a self-sufficient, self-regulating system. It has a structure having the biotic and abiotic components. Location, size, depth and substrates of a pond influence the biology of the pond ecosystem.

1. Abiotic Components:

Abiotic components are the non-living components of the ecosystem. The chief substrates of these ecosystems are heat, light, pH value of water and the basic inorganic and organic compound such as water itself, CO₂, O₂, Ca, N, P, amino acid etc. These substrates of the pond ecosystem influence the organisms of pond or freshwater by directly or indirectly.

2. Biotic Components:

The living components of the ecosystem are biotic components or living component is categorized into 3 types: a) Producers b)Consumers, and c) Decomposers.

• Producers:

Producers are autotrophs, green plants and some photosynthetic bacteria. These producers fix radiant energy and with the help of minerals derived from the water and mud. Substances like carbohydrates, protein, lipids etc. are manufactured by producers. Producer is classified as follows:

• Macrophytes:

Mainly rooted larger plants which include partially or completely submerged floating and emergent hydrophytes are macrophytes. The common plants are Hydrilla, Chara, Vallisneria, Nelumbo etc.

• Phytoplanktons:

Minute, floating or suspended lower plants are phytoplanktons. For example;Volvox, Diatoms, Oscillatoriaa, Chlamydomonas etc.

• Consumers:

Consumers are heterotrophs which depend their nutrition on the organic food manufactured by most of the green plant's producers. Consumers may be herbivores and carnivores. Consumers may be sub-classified as:

• Primary Consumers:

Primary Consumers are feeding directly on living plants. So, these are the herbivores. For example fish, mites,beetles etc.

• Secondary Consumers:

They feed directly on primary consumers. For example, frogs, zooplanktons etc.

• Tertiary Consumers:

They are feeding directly on primary and secondary consumers. For example, large fish etc.

• Decomposers:

These are the living organisms, which decomposed the complex dead organic matter of both producers as well as consumers to simple inorganic form. They play an important role in the return of mineral elements again to run the pond ecosystem. They are chiefly bacteria, actinomycetes, and fungi, Penicillium, Aspergillus, Fusarium, Saprolegnia, are most common decomposers in water and mud of the ponds.

Characteristics of Arid Ecosystem (Desert Ecosystem):

An arid land is a desert or other area with a dry climate and has little precipitation. In such area, evaporation exceeds precipitation; precipitation is less than 25 cm (10 inches) a year and often is scattered unevenly throughout the year. This is why such areas have sparse, widely spaced mostly low vegetation.

The species composition of such ecosystem is much more varied and typically due to extremes of both, temperature and water factors. The various biotic components are given as;

1. Producers

   These are shrubs, especially bushes, some grasses and a few trees. The shrubs have a widespread, branched root system with their stems and branches variously modified sometimes a few succulents like cactus area also present. Some lower plants like lichens and xerophytic mosses may also be present.

2. Consumers:

   The most common animals are reptiles and insects, able to live under xeric condition. In addition to them, some nocturnal rodents and birds are also found.

3. Decomposer:

   There are very few decomposers due to poor vegetation and the less amount of dead organic matter decomposition. There are some fungi and bacteria, most of which are thermophilic.

Characteristics of Wetland Ecosystem in Nepal:

Wetlands are sites distinguished by the presence of water, which often have unique soils that differ from adjacent uplands and support vegetation adapted to wet conditions. They comprise a wide range or island coastal and marine habitats characterized by the presence of flood-tolerant vegetation.

Nepal has many different types of wetlands that range from areas of permanently flowing rivers to areas of seasonal streams, lowland, oxbow lakes, high altitude glacial lakes, swamps and marshes, paddy field, reservoirs and ponds.

Wetlands in Nepal are rich in biological diversity and are known to regularly support more than twenty thousand waterfalls during the test period between “December-February”. They are broadly classified into two categories: natural and man-made.

The natural wetlands comprise lakes and ponds, riverine floodplains, swamps and marshes while man-made include water storage and deep water agriculture ponds (IUCN Nepal 1996).

• Wetland Flora:

Wetlands support a wide variety of habitats for an occurrence of aquatic flora. About 172 species of the major wetland plants are listed by IUCN. Aquatic and marshy plants that are common in Nepal include Lotus (Nelumbo nucifera), Water chestnut (Trapa quadrispinusa), water hyacinth (Eichhornia Crassibes), Hydrilla verticillate, Saccharum spontaneous etc.

• Wetland Fauna:

Out of 833 birds species found in Nepal, 193 are known to be dependent on wetlands. Of these wetland-dependent species about 187 are known to be dependent on the wetlands of the terai; 180 species of water birds are reported from Koshi Tappu and the Koshi barrage.

The diverse wetlands floras of the different ecological zones are significant producers in ecosystems that support a different population of amphibians and fishes and also attract many birds. The gharial and marsh mugger, two species of crocodile are the largest reptiles found in the Kali Gandaki River and major tributaries of the Narayani River.

Wetlands are among the most productive ecosystem in the world. They are very important in terms of their ecological, economic, cultural and recreational values.

Earth as a Closed System:

It isn’t, particularly where energy is concerned. It is constantly receiving a significant amount of energy from the Sun. In terms of matter, it’s a semi-closed system, in that some minor exchanges take place (arrival of new matter by meteoric activity, loss of light gasses such as hydrogen or helium through diffusion into the interplanetary medium), matter is generally cycled through the various spheres via such mechanics as the carbon cycle, nitrogen cycle etc. It was a lot less closed during the heavy bombardment phase of the solar system.

References:

E.p., Odum. Fundamentals of Ecology. USA: W.B Saunters Company, n.d.

Jr., Miller G.T. Living in the Environment. Belmont, California, USA: Wadsworth Publishing Company, 2003.