Broadly, substances occurring naturally on Earth that are valuable and usable in their almost "unmodified" or natural form are called natural resources. Conservation of natural resources refers to the judicious use of the earth's resources by mankind.
Natural resources may be renewable or non-renewable. Renewable resources include solar radiation, geothermal energy, wind and tides - which are inexhaustible resources with unlimited supply that will not run out in the foreseeable future. Other forms of renewable resources are water, soil, forest and wildlife - which have the capacity to replenish themselves provided their rate of consumption does not exceed their natural rate of replacement. Non-renewable resources include "fossil fuels" - like coal and petroleum - and minerals. While metallic minerals can be recycled, fossil fuels cannot be re-used.
Depletion of Natural Resources
Depletion - i.e. consumption of resources faster than their replenishment - may occur due to some human activities like overpopulation, mining of fossil fuels / minerals, slash-and-burn agricultural practices and technological/ industrial development. Some basic industrial minerals (eg copper,zinc,aluminium,coal,iron) are likely to enter production decline in the near future. The decline in supply of petroleum, coupled with increasing demand, is likely to shoot up prices of products derived from petroleum - especially the fuel used for transportation.
Protection.
World Charter for Nature was adopted by United Nations member nation-states on October 28, 1982. It proclaims five "principles of conservation by which all human conduct affecting nature is to be guided and judged."
Fresh water is a sustainable natural resource, that needs to be protected in order to meet its current and future demand adequately. Water conservation efforts help in conserving energy (ie the energy spent on pumping, delivery and purification) and preserving the local wildlife in fresh aquatic ecosystems. Fresh water crisis can be averted as long as water withdrawn from an ecosytem does not exceed its rate of replenishment.
One of the most effective ways of preventing wastage of water is by water metering - a method that helps water departments keep a tab on the water supplied to households and commercial establishments. Not only does this help in monitoring water usage patterns, but it also helps in identifying leakages.
Conservation of water at residential, academic, commercial and public service buildings can be done through harvesting rain water, reusing greywater, retrofitting bathroom accessories and installing various water-saving appliances - eg low-flow taps and shower heads, low/dual-flush toilets, automatic / aerator-based faucets, high-efficiency clothes washers and water-saving garden hose nozzles.
In the agricultural sector, water conservation efforts are primarily aimed at improving the efficiency of the existing irrigation system and minimizing losses due to run-off or evaporation.
Further, the use of mulch, animal manure and organic fertilizers can help increase the water holding capacity of soil and its ability to absorb water - which is helpful especially during dry seasons. Modern irrigation techniques that can be applied include overhead and - where affordable - drip irrigation.
Soil Conservation
Soil conservation entails prevention of erosion or alteration of its chemical composition due to salination, acidification, contamination or overuse.
Measures to prevent soil erosion include age-old practices like contour and terrace farming. Ither methods are crop rotation and growing cover crops. Creating widbreaks - by planting rows of trees - and perimeter treatment (with shrubs and ground-covers) are effective ways of preventing erosion by wind and rainwater respectively.
Salinization can be controlled using humic acids and saline-tolerant plants like saltbush.
Soil organisms and addition of crushed rocks can help retain the soil's mineral content.
Forests - areas of high densities of trees - cover nearly one-third of our planet's land area. About 1.6 billion people depend on the forests for their livelihood.
Being repositories of biological diversity, forests are home to a wide variety of flora and fauna. Apart from providing vital plant-based products - food, wood, timber, medicinal herbs, fibres, dyes, rubber and animal fodder - forests help in conserving water and soil, provide oxygen, absorb pollution, mitigate effects of climate change, and protect the watersheds that provide freshwater to nearly 76% of the population worldwide. Moreover, they serve as locations of education, entertainment and ecotourism.
The efforts of conservation of forests aim at maintaining, planning and developing forested areas sustainably in order to meet the socio-economic and environmental needs of the current and future generations.
A significant area of forest cover is lost worldwide because of deforestation. In developing countries, deforestation mostly occurs due to felling of trees for fuelwood, shifting cultivation, and clearing of forest land for agriculture or infrastructural development. Removal of extensive areas of trees can increase the flow of surface water and erode the soil. It can reduce the amount of water that get transpired into air, thereby causing rainfall to lessen. Further, the groundwater recharge will get reduced. All these factors may ultimately lead to drought.
Forests need to be both protected and harvested selectively. Countries need to earmark forest areas for conservation (protecting the integrity of the forest ecosystem) as well as sustainable production of forest goods and services. To meet the demand for wood, for fuel or otherwise, some sustainable production process can be used or tree plantations can be grown. The tree plantations can help alleviate the over-harvesting of the natural forests.
Administrative bodies should encourage local communities to participate in the conservation process. Authorities must ensure that the cost of production of commodities obtained from the forest resources include expenses incurred on afforestation efforts.
Measures need to be taken to protect forests from forest fires, acid rain and other air-borne pollutants.
Individuals can help by spreading awareness about the ecological and environmental importance of forests.
Wildlife Conservation
Wildlife conservation efforts primarily aim at protecting the lives and habitats of wild plant and animal species. Certain human activities - like agriculture, commercial development, oil/gas exploration and building of bridges - often destroy wildlife habitats as they may involve felling of trees, dredging of rivers and filling in wetlands. Further, habitats may get fragmented by construction of dams/roads/railways or diversion of water bodies. Other threats to wildlife include climate changes, pollution, poaching and over-exploitation (like over-grazing and excessive fishing) of natural resources.
Population growth and infrastructural development often overlap with established wildlife habitats causing unexpected interaction between people and wild animals - a phenomenon popularly known as Human-Wildlife conflict. This conflict leads to injuries and fatalities - affecting both people and animals - and is a growing botheration for people living near ecologically sensitive areas. Recommended solutions to minimize such conflicts include - among many - measures like behavioural modification, trans-location and regulation of animal populations and community-based natural resource management. Further, awareness campaigns need to be conducted among people to create better understanding of wildlife and identification/protection of endangered species. Also, people must refrain from introducing any foreign species in isolated ecosystems.
It's essential to know one's local wildlife and make efforts to protect the woods in one's area. Woods provide food, water, shelter and space that the wild animals and birds desperately seek. So ponds, springs or wetlands need to be protected, as they are major attractions for wildlife. Backyard gardens can be made lively with birds and butterflies by creating a Wildlife-friendly landscape.