Aug 082012
 

Biodiversity is the total variety of life on the earth. It encompasses the total number, variety and variability of life forms, levels and combinations existing within the living world. This includes diversity within species, between species and of ecosystems.

Biodiversity can also be defined as all the types of species of plants, animals and other living beings present on earth. It consists of three fundamental and hierarchical categories which are mentioned and described below:

1. Ecosystem diversity: It comprises a variety of habitats, dynamic complexity of plant, animal and micro-organism communities and their non-living environment which interact as a functional unit. Non-living components include sunlight, air, water, minerals and nutrients.

2. Species diversity: A species may be defined as a group of individuals or as a population of organisms which resemble each other very closely and can interbreed with each other successfully for reproducing their own kind.

Species diversity refers to the frequency and variety of species (wild or domesticated) within a geographical area. Species diversity is usually measured in terms of the total number of species within discrete geographical boundaries. The total number of species in the globe has been estimated by World Conservation Monitoring Center to range from five to thirty million and approximately 1.7 million living species of all kinds of organisms have been described till date (WCMC 1992).

3. Genetic diversity: Genetic diversity refers to variation of genes and or genomes within living organisms, that is the genetic differences among populations of a single species and among individuals within a population. In other words, this covers distinct populations of the same species such as hundreds of traditional rice varieties in Nepal.

Scope of Biodiversity

Biodiversity has its own scope and importance. Some of the scopes of biodiversity are given below in points:

1. Early humans learned much about plants and animals, because they had to depend upon them for food and other requirements.

2. Biodiversity (plants and animals) constitute the structural component of ecosystem.

3. Wild variety of plants, animals, birds and other living beings are the gene banks of nature. These are of extreme importance in breeding programmes in agriculture and animal husbandry.

4. Biodiversity is an integral part of nature. It provides beauty to nature.

5. Wildlife provides valuable information to naturalists and biologists in understanding the environment, ecology and behaviour. These animals and plants are also used to study the effects of pollution.

6. Several wild species of plants and animals are widely used in medicine. They are mostly used in curative and rehabilitative health care system.

7. Wild species of plants and animals are economically most important for human life as they are used in various ways. Animal products like feather, skin, horn etc, fetch good money in the international market.

8. Wildlife provides the best means of sports and recreation. The country can earn good amount of money by attracting tourists as wildlife is linked with tourism.

9. Forests maintain the water cycle and gaseous cycle of the environment, which regulate the climate and quality of the environment.

10. Forest reduces the greenhouse effect of the environment.

Apr 232012
 

Human beings use natural resources like land, water, minerals while conducting  construction works, namely, drainage, canal, road etc. The activities like formation of new machines, experiments and research always go on. Various human activities adversely affects on biodiversity. People should play vital role on reducing such adverse effects and conservation of living beings.

The adverse effects on biodiversity and the methods to mitigate them may differ from place to place because of different geographical regions. There may be some similarity. Some measures to mitigate the effects are given below:

1. Degradation of Ecosystem
There are different types of living beings in the terrestrial and aquatic ecosystems. Cattle, birds, insects, plants and trees grow in the terrestrial ecosystem while fish, some insects, small plants live in the aquatic  ecosystem. The terrestrial ecosystem is degraded due to forest fire, destruction of the forest, use of insecticides and pesticides and construction of work. Aquatic ecosystem is spoil by falling stones and soil when construction work is done and by explosions. Adverse effects on water is caused when sewage mixes with water sources. Thus, the living beings both on land and in water are affected. Large mammals like tiger, elephant,  rhinoceros etc. require enough physical surroundings for their maintenance. But on account of degraded ecosystem, there is shortage of space for the living beings.

2. Loss of Habitat
Habitat plays a significant role in retaining biodiversity. Natural habitat is ruined because of human activities like construction work, expansion of agricultural work, excessive use of chemicals, destruction of forest etc. As a result, animal’s habitat, food-cycle, climate and reproduction progress are badly affected. The numerical growth of living beings and their life-style are hampered, and so there is decline in the ecosystem. Due to the loss of the habitat, there is struggle among the species for food and shelter. Consequently, the number of incompetent vegetation, animals and birds go on decreasing. Eventually many living beings vanish. Human beings too are affected.

It is wise to destroy the natural habitat while conducting development construction and human activities. The activities which has been destroyed should be restored. For example, trees should be planted in bare and uncultivated places. This will create the natural habitat for the living beings. Rivers, rivulets and other water resources should not be filled. They should be protected from filling stone and mud. Those places should be restored to the former natural forms.

3. Loss of Mobility
The deterioration of the natural environment causes the loss of mobility of animals and birds. The causes of the deterioration of the environment are the destruction of the forest, expansion of agricultural land and urbanization. All these factors limit the space for the animals and birds for roaming. That is why, the natural environment for the animals like tiger, elephant, deer, bird has diminished. In this situation, they have to stay within a limit area. So, people should not ruin the natural environment if they want to conserve the animals and birds. We should try to make the dry and  uncultivated land suitable for the habitat of animals.

4. Limitation of Expansion of Vegetation
Land for cultivation is extended due to population growth. Various types of development and construction work are continuing. Similarly, settlement areas are expanding and urbanization is taking place. Grazing land is declining in size. These activities are causing loss to the forest, vegetation, herbs etc. Because of these unsuitable effects, biodiversity is degrading. People should grow trees in the surrounding of their houses, either side of the road and bare fields. Pasture lands should not be damaged. Grass should be grown in the barren place for the cattle. Thus, the greenery can be increased.