Syllabus
GS Paper III – Conservation, environmental pollution and degradation, environmental impact assessment.
Context
A study published in ‘Global Change Biology’ discovered that the rise in tree cover within savannahs and grasslands has resulted in a decline of over 20% in native grassland bird populations, especially in the African Savannah.
Woody Encroachments in Grasslands
Introduction
In India, grasslands span various climatic regimes, including the high-altitude Shola grasslands of the Western Ghats, the arid grasslands of western and interior India, and the floodplain grasslands of the Himalayan belt. These ecosystems play a crucial role in supporting biodiversity and providing essential ecosystem services. They are home to megaherbivores such as elephants, rhinoceroses, and buffaloes in Africa and Asia, as well as grassland birds like bustards and floricans.
Grasslands
Grasslands are expansive open areas where grass is the predominant plant species. Covering nearly 40% of the earth’s total landmass, these ecosystems are vital habitats for many endemic and at-risk species of plants and animals. Grasslands occur in both tropical and temperate regions.
Tropical Grasslands (Savannahs)
- Location: Found in regions near the equator, primarily in Africa, South America, and Australia.
- Climate: Characterized by warm temperatures year-round with distinct wet and dry seasons.
- Vegetation: Dominated by grasses with scattered trees and shrubs.
- Wildlife: Home to megafauna like elephants, lions, giraffes, and rhinoceroses.
- Examples: Notable examples include the Serengeti in Africa.
Temperate Grasslands
- Location: Found in mid-latitude regions such as North America, South America, and Eurasia.
- Climate: Characterized by hot summers and cold winters with moderate rainfall.
- Vegetation: Dominated by a variety of grasses with few trees.
- Wildlife: Hosts species like bison, antelope, and various rodents and birds.
- Examples: Examples include the North American prairies and Eurasian steppes.
What has the Study Revealed?
- Diverse Habitats:
- Found in tropical and temperate regions.
- Cover nearly 40% of the Earth’s landmass.
- Biodiversity:
- Home to large herbivores like elephants and rhinoceroses.
- Grassland birds such as bustards and floricans.
- Decline:
- Rapidly declining due to various threats.
- Woody Encroachment:
- Gradual transformation of open habitats into areas with higher tree and shrub density.
- Shift from a diverse grassy understory to a uniform woody cover.
- Contributing factors: Climate change, increased atmospheric CO2, disruption of natural disturbance regimes like grazing and fire.
- Effects on Ecosystems:
- Increase in tree cover has detrimental effects.
- Higher CO2 levels promote growth of deep-rooted woody plants, overshadowing and suppressing grasses.
- Alters soil conditions and faunal associations, leading to declines in grassland species and disrupting ecological balance.
- Global and Local Impact:
- South America: Fire suppression as a major driver.
- Australia and Africa: Increased CO2 and variations in rainfall.
- India: Threats from natural encroachment and large-scale tree plantation programs.
- Significant woody encroachment in national parks, with grassland habitats shrinking by 34% and tree cover increasing by 8.7% over the past three decades.
- Human Influence:
- Historical policies viewed open ecosystems as “wastelands”, leading to conversion for timber and agricultural use.
- Modern focus on carbon sequestration further pressures these habitats.
- Mitigation and Conservation:
- Gather more evidence on the impact of woody encroachment.
- Conduct long-term ecological monitoring.
- Challenge outdated colonial terminologies that misclassify open ecosystems.
- Promote conservation strategies that consider the ecological value of grasslands and maintain their biodiversity and resilience.
Woody encroachments
- Definition: It entails the conversion of open habitats to areas with greater tree cover and/or shrub density.
- Causes:
- Disruptions in Disturbance Regimes: When there are disruptions in natural disturbance regimes, trees have the calm they need to establish themselves and start woody encroachment.
- Fire Suppression, Fragmentation, and Rainfall Variations: These factors further contribute to woody encroachment, especially in South America, Australia, and Africa.
- Colonial Classification: The colonial classification of open ecosystems as ‘wastelands’ promoted timber cultivation.
- Tree Plantation Drives: These drives lead to encroachments.
- Examples:
- Banni Grasslands: The Gujarat government planted the invasive species Prosopis Juliflora in the Banni grassland from 1961 to combat desertification and provide firewood to communities, transforming swaths of the grasslands into a Prosopis woodland.
- Shola Grasslands: Eucalyptus plantations have encroached upon these grasslands.
- Wet Terai Grasslands of the Himalaya: The Malabar silk-cotton tree has been running riot here.
- Climate Change Impact:
- Increased Atmospheric CO2: Due to climate change, increased atmospheric CO2 favors tree growth over grasses because the C3 photosynthetic pathway used by trees is favored under high CO2 conditions.
- Dominance of Trees: Once trees become dominant in a system, they may further suppress grasses through shading and fire suppression.
Threats to Grasslands
- Conversion to Agriculture: Grasslands are often converted into agricultural land to meet the growing demand for food production.
- Erosion: Without the deep root systems of grasses to hold the soil in place, grasslands are susceptible to erosion.
- Large-Scale Development: Urbanization and infrastructure projects encroach on grassland areas, leading to habitat fragmentation and loss.
- Overgrazing: Overgrazing reduces biodiversity, compacts the soil, and makes the land more vulnerable to erosion.
- Woody Encroachment: An often-overlooked threat is the increase of tree and shrub cover, known as woody encroachment.
Impact of Declining Grasslands
- Ecological Impacts:
- Loss of Biodiversity: Grasslands support diverse species of plants, insects, birds, and mammals. Their decline leads to habitat loss, threatening species specially adapted to these environments.
- Disruption of Ecosystem Services: Grasslands provide vital ecosystem services such as soil stabilisation, water filtration, and carbon sequestration. Their degradation can reduce these services, impacting soil health, water quality, and climate regulation. Their decline can lead to increased atmospheric CO2 levels, exacerbating climate change.
- Altered Fire Regimes: Grasslands help maintain natural disturbances like fire. When grasslands decline, the frequency and intensity of fires can change, further altering ecosystem dynamics.
- Environmental Impacts:
- Increased Soil Erosion: Grasslands help bind soil with their root systems. Without them, soils are more prone to erosion, leading to loss of topsoil and land degradation.
- Altered Water Cycles: Grasslands play a role in maintaining hydrological cycles by regulating water infiltration and runoff. Their loss can lead to changes in local and regional water cycles, potentially causing flooding or reduced water availability.
- Socio-Economic Impacts:
- Impact on Livelihoods: Many communities rely on grasslands for grazing livestock and other agricultural activities. The decline in grasslands can negatively affect these livelihoods, leading to economic hardship for pastoralists and farmers.
- Reduced Agricultural Productivity: The loss of grasslands can lead to a decrease in soil fertility and productivity, affecting crop yields and food security.
Way forward
- Designate Protected Areas: Establish protected areas and conservation reserves to safeguard remaining grasslands from development and other threats.
- Restore Degraded Lands: Implement ecological restoration projects to rehabilitate degraded grasslands, including replanting native grasses and controlling invasive species.
- Promote Sustainable Agriculture: Encourage practices that reduce soil disturbance, such as no-till farming and rotational grazing, to maintain soil health and prevent erosion.
- Implement Controlled Grazing: Develop and enforce grazing management plans that prevent overgrazing and allow for natural recovery periods of grassland ecosystems.
- Control Invasive Plants: Monitor and manage invasive species that outcompete native grasses and disrupt the ecosystem balance.
- Enforce Land Use Regulations: Strengthen and enforce policies and regulations that prevent the conversion of grasslands to agricultural or urban uses.
- Support Incentives for Conservation: Provide financial incentives and support for landowners who engage in grassland conservation and sustainable land management practices.
- Involve Local Communities: Engage local communities in conservation efforts, including education about the value of grasslands and involving them in restoration projects.
Conclusion
It is crucial to develop comprehensive evidence of woody encroachment’s impact on ecosystems and to monitor open ecosystems over the long term, as they provide valuable fine-scale information. Acknowledging the historical presence and ecological importance of grasslands is vital, and dismantling colonial terminologies like “wastelands” that misclassify these ecosystems is essential. Implementing informed policies and practices will help protect these ecosystems for future generations. Promoting agroecological methods and rotational grazing systems, along with following successful restoration projects like those in Maharashtra, demonstrates the potential for effective grassland conservation.
Reference: TH
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Practice Question
Declining grasslands pose a significant threat to global biodiversity and ecosystem health. Examine the major impacts of this decline on ecosystems and biodiversity. [250 words]