Biology

Learninsta presents the core concepts of Biology with high-quality research papers and topical review articles.

Environmental Conservation Issues

India due to its topography, geology and climate patterns has diverse life forms. Now this huge diversity is under threat due to many environmental issues for this conservation becomes an important tool by which we can reduce many species getting lost from our native land.

By employing conservation management strategies like germplasm conservation, in situ, ex-situ, in-vitro methods, the endemic as well as threatened species can be protected and also have educational and recreational values for the society.

In-situ conservation:

It means conservation and management of genetic resources in their natural habitats. Here the plant or animal species are protected within the existing habitat. Forest trees, medicinal and aromatic plants under threat are conserved by this method. This is carried out by the community or by the State conservation which include wildlife, National park and Biosphere reserve.

The ecologically unique and biodiversity rich regions are legally protected as wildlife sanctuaries, National parks and Biosphere reserves. Megamalai, Sathyamangalam wildlife, Guindy and Periyar National park, and Western ghats, Nilgiris, Agasthyamalai and Gulf of Mannar are the biosphere reserves of Tamil Nadu.

Sacred groves

These are the patches or grove of cultivated trees which are community protected and are based on strong religious belief systems which usually have a signifiant religious connotation for protecting community. Each grove is an abode of a deity mostly village God Or Goddesses like Aiyanar or Amman.

448 grooves were documented throughout Tamil Nadu, of which 6 groves (Banagudi shola, Thrukurungudi and Udaiyankudikadu, Sittannnavasal, Puthupet and Devadanam) were taken up for detailed floristic and faunistic studies. These groves provide a number of ecosystem services to the neighbourhood like protecting watershed, fodder, medicinal plants and micro climate control.

Ex-situ conservation

It is a method of conservation where species are protected outside their natural environment. This includes establishment of botanical gardens, zoological parks, conservation strategies such as gene, pollen, seed, in-vitro conservation, cryo preservation, seedling, tissue culture and DNA banks. These facilities not only provide housing and care for endangered species, but also have educational and recreational values for the society.

Endemic Centres and Endemic Plants

Endemic species are plants and animals that exist only in one geographic region. Species can be endemic to large or small areas of the earth. Some are endemic to a particular continent, some to a part of a continent and others to a single island. Any species found restricted to a specified geographical area is referred to as ENDEMIC. It may be due to various reasons such as isolation, interspecific interactions, seeds dispersal problems, site specifiity and many other environmental and ecological problems.

There are 3 Megacentres of endemism and 27 microendemic centres in India. Approximately one third of Indian flora have been identified as endemic and found restricted and distributed in three major phytogeographical regions of india, that is Indian Himalayas, Peninsular India and Andaman nicobar islands.

Peninsular India, especially Western Ghats has high concentration of endemic plants. Hardwickia binata and Bentinckia condapanna are good examples for endemic plants. A large percentage of Endemic species are herbs and belong to families such as Poaceae. Apiaceae, Asteraceae and Orchidaceae.

Majority of endemic species are threatened due to their narrow specifi habitat, reduced seed production, low dispersal rate, less viable nature and human intereferences.. Serious efforts need to be undertaken for their conservation, otherwise these species may become globally extinct.

Learninsta presents the core concepts of Biology with high-quality research papers and topical review articles.

Alien Invasive Species | Eichhornia Crassipes | Prosopis Juliflra

Invasion of alien or introduced species disrupts ecosystem processes, threaten biodiversity, reduce native herbs, thus reducing the ecosystem services (benefis). During eradication of these species, the chemicals used increases greenhouse gases.

Slowly they alter ecosystem, micro climate and nature of soil and make it unsuitable for native species and create human health problems like allergy, thus resulting in local environmental degradation and loss of important local species. According to World Conservation Union invasive alien species are the second most signifiant threat to bio-diversity after habitat loss.

What is invasive species?

A non-native species to the ecosystem or country under consideration that spreads naturally, interferes with the biology and existence of native species, poses a serious threat to the ecosystem and causes economic loss. It is established that a number of invasive species are accidental introduction through ports via air or sea.

Some research organisations import germplasm of wild varieties through which also it gets introduced. Alien species with edible fruits are usually spread by birds. Invasive species are fast growing and are more adapted. They alter the soil system by changing litter quality thereby affecting the soil community, soil fauna and the ecosystem processes.

It has a negative impact on decomposition in the soils by causing stress to the neighbouring native species. Some of the alien species which cause environmental issues are discussed below.

Eichhornia crassipes:

It is an invasive weed native to South America. It was introduced as aquatic ornamental plant, which grows faster throughout the year. Its widespread growth is a major cause of biodiversity loss worldwide. It affects the growth of phytoplanktons and finally changing the aquatic ecosystem.

It also decreases the oxygen content of the waterbodies which leads to eutrophication. It poses a threat to human health because it creates a breeding habitat for disease causing mosquitoes (particularly Anopheles) and snails with its free flating dense roots and semi submerged leaves. It also blocks sunlight entering deep and the waterways hampering agriculture, fiheries, recreation and hydropower.

Prosopis juliflra

Prosopis juliflra is an invasive species native to Mexico and South America. It was first introduced in Gujarat to counter desertifiation and later on in Andhra Pradesh, Tamil Nadu as a source of firewood. It is an aggressive coloniser and as a consequence the habitats are rapidly covered by this species.

Its invasion reduced the cover of native medicinal herbaceous species. It is used to arrest wind erosion and stabilize sand dunes on coastal and desert areas. It can absorb hazardous chemicals from soil and it is the main source of charcoal.

Learninsta presents the core concepts of Biology with high-quality research papers and topical review articles.

An Overview Of Afforestation And Its Acheivements

Afforestation is planting of trees where there was no previous tree coverage and the conversion of non-forested lands into forests by planting suitable trees to retrieve the vegetation. Example: Slopes of dams affrested to reduce water runoff erosion and siltation. It can also provide a range of environmental services including carbon sequestration, water retention.

Afforestation Objectives

• To increase forest cover, planting more trees, increases O₂ production and air quality.
• Rehabilitation of degraded forests to increase carbon fiation and reducing CO₂ from atmosphere.
• Raising bamboo plantations.
• Mixed plantations of minor forest produce and medicinal plants.
• Regeneration of indigenous herbs / shrubs.
• Awareness creation, monitoring and evaluation.
• To increase the level and availability of water table or ground water and also to reduce nitrogen leaching in soil and nitrogen contamination of drinking water, thus making it pure not polluted with nitrogen.
• Nature aided artifiial regeneration.

Achievements

• Degraded forests were restored
• Community assets like overhead tanks bore-wells, hand pumps, community halls, libraries, etc were established
• Environmental and ecological stability was maintained.
• Conserved bio-diversity, wildlife and genetic resources.
• Involvement of community especially women in forest management.

Learninsta presents the core concepts of Biology with high-quality research papers and topical review articles.

Environmental Deforestation | Definition, Causes and Effects

Deforestation is one of the major contributors to enhance green house effect and global warming. The conversion of forested area into a non-forested area is known as deforestation. Forests provide us many benefits including goods such as timber, paper, medicine and industrial products. The causes are

• The conversion of forests into agricultural plantation and livestock ranching is a major cause of deforestation.
• Logging for timber
• Developmental activities like road construction, electric tower lines and dams.
• Over population, Industrialisation, urbanisation and increased global needs.

Effects of deforestation

• Burning of forest wood release stored carbon, a negative impact just opposite of carbon sequestration.
• Trees and plants bind the soil particles. The removal of forest cover increases soil erosion and decreases soil fertility. Deforestation in dry areas leads to the formation of deserts.
• The amount of run of water increases soil erosion and also creates flash floding, thus reducing moisture and humidity.
• The alteration of local precipitation patterns leading to drought conditions in many regions. It triggers adverse climatic conditions and alters water cycle in ecosystem.
• It decreases the bio-diversity signifiantly as their habitats are disturbed and disruption of natural cycles.
• Loss of livelihood for forest dwellers and rural people.
• Increased global warming and account for one-third of total CO₂ emission.
• Loss of life support resources, fuel, medicinal herbs and wild edible fruits.

Learninsta presents the core concepts of Biology with high-quality research papers and topical review articles.

Environmental Issues On Various Types Of Forestry

Agro forestry

Agroforestry is an integration of trees, crops and livestock on the same plot of land. The main objective is on the interaction among them. Example: intercropping of two or more crops between diffrent species of trees and shrubs, which results in higher yielding and reducing the operation costs. This intentional combination of agriculture and forestry has varied benefits including increased bio-diversity and reduced erosion.

Some of the major species cultivated in commercial Agroforestry include Casuarina, Eucalyptus, Malai Vembu, Teak and Kadambu trees which were among the 20 species identified as commercial timber. They are of great importance to wood-based industries.

Benefits of agroforestry

• It is an answer to the problem of soil and water conservation and also to stabilise the soil (salinity and water table) reduce landslide and water run-of problem.
• Nutrient cycling between species improves and organic matter is maintained.
• Trees provide micro climate for crops and maintain O₂ – CO₂ balanced, atmospheric temperature and relative humidity.
• Suitable for dry land where rainfall is minimum and hence it is a good system for alternate land use pattern.
• Multipurpose tree varieties like Acacia are used for wood pulp, tanning, paper and firewood industries.
• Agro-forestry is recommended for the following purposes. It can be used as Farm Forestry for the extension of forests, mixed forestry, shelter belts and linear strip plantation.

Rehabilitation of degraded forests and recreation forestry

The production of woody plants combined with pasture is referred to silvopasture system. The trees and shrubs may be used primarily to produce fodder for livestock or they may be grown for timber, fuel wood and fruit or to improve the soil. This system is classified into following categories.

(i) Protein Bank:

In this various multipurpose trees are planted in and around farm lands and range lands mainly for fodder production. Example: Acacia nilotica, Albizzia lebbek, Azadirachta indica, Gliricidia sepium, Sesbania grandiflora.

(ii) Livefence of fodder trees and hedges:

Various fodder trees and hedges are planted as live fence to protect the property from stray animals or other biotic inflences. Example: Gliricidia sepium, Sesbania grandiflra, Erythrina spp., Acacia spp.

Social forestry

It refers to the sustainable management of forests by local communities with a goal of climate carbon sequestration, change mitigation, depollution, deforestation, forest restoration and providing indirect employment opportunity for the youth.

Social forestry refers to the management of forests and afforestation on barren lands with the purpose of helping the environmental, social and rural development and benefits. Forestry programme is done for the benefit of people and participation of the people. Trees grown outside forests by government and public organisation reduce the pressure on forests.

In order to encourage tree cultivation outside forests, Tree cultivation in Private Lands was implemented in the state from 2007-08 to 2011-12. It was implemented by carrying out block planting and inter-crop planting with profitable tree species like Teak, Casuarina, Ailanthus, Silver Oak, etc in the farming lands and by a free supply of profiable tree species for planting in the bunds.

The Tank foreshore plantations have been a major source of firewood in Tamil Nadu. The 32 Forestry extension centres provide technical support for tree growing in rural areas in Tamil Nadu. These centres provide quality tree seedlings like thorn / thornless bamboo, casuarinas, teak, neem, Melia dubia, grafted tamarind and nelli, etc in private lands and creating awareness among students by training / camps.

Major activities of forestry extension centres

• Training on tree growing methods
• Publicity and propaganda regarding tree growing
• Formation of demonstration plots
• Raising and supply of seedlings on subsidy
• Awareness creation among school children and youth about the importance of forests through training and camps.