Q1. Explain the Key Principles of the Ecosystem Approach to Conserving Natural Resources
The ecosystem approach is a comprehensive and holistic strategy for conserving natural resources by recognising ecosystems as dynamic systems composed of plants, animals, microorganisms, humans and their physical environment. Rather than focusing on individual species or isolated resources, this approach manages land, water and living resources together to ensure ecological integrity and sustainability.
A key principle of the ecosystem approach is holistic management. Ecosystems function through complex interactions such as nutrient cycling, energy flow and food webs. Any disturbance to one component affects the entire system. Therefore, conservation planning must consider interconnections among biotic and abiotic components.
Biodiversity conservation is another fundamental principle. Genetic, species and ecosystem diversity enhance ecosystem stability and resilience against disturbances such as climate change, pests and natural disasters. Diverse ecosystems provide essential services like pollination, soil fertility, water purification and climate regulation.
Sustainable use of natural resources is central to the ecosystem approach. It emphasises using resources within the regenerative capacity of ecosystems so that present needs are met without compromising future generations. Sustainable forestry, fisheries and agriculture are practical applications of this principle.
The ecosystem approach also recognises humans as an integral part of ecosystems. It encourages stakeholder participation, community involvement and the use of traditional ecological knowledge in decision-making. Adaptive management is promoted to respond to changing environmental conditions through continuous monitoring and learning.
Overall, the ecosystem approach integrates conservation with development, ensuring ecological balance, social equity and long-term sustainability.
Q2. Explain the Human Impact on Ecosystem Functioning, Global Energy Flow, Food Security and Public Health
Human activities have profoundly altered natural ecosystems across the globe. Deforestation, industrialisation, urbanisation, intensive agriculture and pollution disrupt ecosystem functioning by altering nutrient cycles, reducing biodiversity and weakening ecosystem resilience.
Changes in land use and excessive exploitation of natural resources affect global energy flow. Conversion of forests and grasslands into agricultural or urban areas reduces primary productivity and disturbs energy transfer across trophic levels. Dependence on fossil fuels has increased greenhouse gas emissions, leading to climate change and further disruption of ecosystem energy balance.
Food security is closely linked to healthy ecosystems. Soil degradation, water scarcity, loss of pollinators and climate variability reduce agricultural productivity. Overfishing and destruction of marine habitats threaten fisheries and livelihoods. Climate-induced extreme events such as floods and droughts further increase the risk of food shortages.
Public health is directly and indirectly affected by ecosystem degradation. Air and water pollution cause respiratory and water-borne diseases, while deforestation and habitat loss increase the spread of vector-borne and zoonotic diseases. Climate change intensifies heat stress, disasters and health risks. Thus, environmental degradation poses serious threats to human survival and well-being.
Q3. Causes of Land Degradation and Strategies for Ecosystem Restoration
Land degradation refers to the deterioration of the physical, chemical and biological quality of land, resulting in reduced productivity and loss of ecosystem services. It is a major environmental problem affecting agricultural output, biodiversity and human livelihoods.
One of the primary causes of land degradation is deforestation. Removal of forest cover for agriculture, mining, urban development and infrastructure exposes soil to erosion by wind and water. Forests play a vital role in maintaining soil fertility, regulating water cycles and preventing landslides.
Unsustainable agricultural practices such as over-cultivation, monocropping, excessive use of chemical fertilisers and pesticides degrade soil structure and reduce organic matter. Improper irrigation leads to waterlogging and soil salinisation, particularly in arid and semi-arid regions.
Overgrazing by livestock exerts continuous pressure on grasslands, preventing vegetation regeneration and exposing soil to erosion. Mining and industrial activities remove topsoil and contaminate land with toxic substances. Climate change further accelerates land degradation through droughts, floods and extreme weather events.
Ecosystem restoration strategies aim to recover degraded land and restore ecological balance. Afforestation and reforestation using native species stabilise soil and enhance biodiversity. Sustainable land management practices such as crop rotation, organic farming and reduced chemical inputs improve soil health.
Soil and water conservation measures including terracing, contour farming, bunding, check dams and rainwater harvesting reduce erosion and enhance groundwater recharge. Community participation, policy support and awareness are essential for the long-term success of restoration programmes.
Q4. Short Notes
(c) Kyoto Protocol
The Kyoto Protocol is an international environmental treaty adopted in 1997 under the United Nations Framework Convention on Climate Change (UNFCCC). It came into force in 2005 with the objective of reducing greenhouse gas emissions responsible for global warming.
The protocol is based on the principle of common but differentiated responsibilities, recognising that developed countries have historically contributed more to climate change. Therefore, legally binding emission reduction targets were assigned mainly to industrialised nations.
To achieve cost-effective reductions, the Kyoto Protocol introduced flexible mechanisms such as Emissions Trading, Joint Implementation and the Clean Development Mechanism (CDM). These allowed countries to earn emission reduction credits through international cooperation.
Although the protocol faced challenges such as limited participation and compliance issues, it played a crucial role in global climate governance and laid the foundation for subsequent agreements like the Paris Agreement.
(d) Biodiversity
Biodiversity refers to the variety of life forms on Earth, including genetic diversity, species diversity and ecosystem diversity. It is fundamental to ecosystem stability, productivity and resilience.
Biodiversity provides essential ecosystem services such as food production, pollination, nutrient cycling, climate regulation and medicinal resources. High biodiversity enables ecosystems to withstand environmental stresses and disturbances.
Human activities such as habitat destruction, pollution, overexploitation, invasive species and climate change have led to rapid biodiversity loss. Conservation of biodiversity through protected areas, sustainable resource use and community participation is essential for sustainable development.
Q5. Community Organisation and Species Interactions
A biological community consists of populations of different species living together and interacting within a particular area. Community organisation is shaped by environmental conditions, disturbances, ecological succession and species interactions.
Abiotic factors such as temperature, rainfall, soil and light determine species distribution and abundance. Disturbances like floods, fires and human activities alter community structure and create opportunities for new species.
Interspecific interactions occur between individuals of different species. These include competition for limited resources, predation, parasitism, mutualism and commensalism. For example, predators regulate prey populations, while mutualistic interactions like pollination benefit both species involved.
Intraspecific interactions occur among individuals of the same species and include competition for food, space and mates, as well as cooperation and social behaviour. Pack hunting in wolves and territorial behaviour in birds are common examples.
These interactions regulate population size, maintain species diversity and contribute to ecosystem stability.
Q6. Causes, Types and Processes of Ecological Succession
Ecological succession is the gradual and orderly change in species composition of a community over time. It occurs due to natural disturbances, biological processes and human activities.
Primary succession takes place on bare, lifeless surfaces such as lava flows and glacial deposits, while secondary succession occurs in disturbed areas where soil is already present, such as abandoned agricultural land.
Succession may also be classified as autogenic, driven by organisms modifying their environment, or allogenic, driven by external environmental factors like climate change.
The process of succession includes stages of nudation, invasion, competition, reaction and stabilisation. The final stage is the climax community, which is relatively stable and self-sustaining.
Q7. Structure and Function of Ecosystem
The structure of an ecosystem refers to the arrangement of its biotic and abiotic components. Abiotic components include climate, soil, water and nutrients, while biotic components consist of producers, consumers and decomposers.
Producers capture solar energy and form the base of the food chain. Consumers depend on producers or other consumers for food, while decomposers recycle nutrients by breaking down dead organic matter.
The major functions of ecosystems include energy flow, primary productivity, nutrient cycling and decomposition. These processes maintain ecological balance, ecosystem stability and sustainability.
Q8. Biogeochemical Cycling of Nitrogen and Phosphorus
The nitrogen cycle involves processes such as nitrogen fixation, nitrification, assimilation, ammonification and denitrification. These processes convert atmospheric nitrogen into usable forms and recycle it back to the atmosphere.
The phosphorus cycle is a sedimentary cycle involving rock weathering, absorption by plants, transfer through food chains, decomposition and sedimentation. Unlike nitrogen, phosphorus does not have a gaseous phase.
Both cycles are essential for ecosystem productivity, soil fertility and sustainable agriculture. Human activities such as excessive fertiliser use disrupt these cycles and cause environmental problems like eutrophication.