Lecture 2: State of Global Environment (Biodiversity)

Environmental Impact Assessment: Biodiversity Overview

Introduction to Biodiversity

• The course focuses on biodiversity as part of the Environmental Impact Assessment, referencing Chapter 6 of the Global Environment Outlook 6.

• Key topics include defining biodiversity, discussing problems like the sixth mass extinction, and exploring its significance and benefits through the concept of One Health.

Understanding Biodiversity

• Biodiversity is defined as the richness and variety of life on Earth, encompassing genetic diversity within species and diversity among ecosystems.

• It is crucial for ecosystem health, stability, and recovery; without it, life cannot sustain itself.

Problems Associated with Biodiversity

• Current evidence indicates a crisis in biodiversity characterized by a permanent decline in genetic and species diversity at both local and global levels.

• Human activities are exerting pressures that could lead to a sixth mass extinction event, significantly impacting health equity.

Sixth Mass Extinction Explained

• A mass extinction occurs when species vanish much faster than they can be replaced; historically defined as losing about 75% of species in a short geological timeframe.

• Current rates of species loss are estimated to be 1000 times greater than background rates, raising concerns about entering a sixth mass extinction.

Impacts on Ecosystems and Resilience

• Loss of biodiversity accelerates habitat decline beyond planetary boundaries, reducing ecosystem resilience against climate change threats.

• Displaced species can become invasive, posing risks to health and food security while diminishing ecosystem efficiency in resource capture.

The Importance of Biodiversity and Its Challenges

Role of Communities in Biodiversity Protection

• Communities are essential for protecting biodiversity, and failure to act will lead to significant costs.

• Biodiversity provides valuable goods and services, including climate regulation, air and water filtration, and disaster mitigation.

Benefits of Biodiversity

• Direct benefits from biodiversity include food, fibers, wood products, fish, pollination services, medicines from plants, and psychological health improvements.

• Loss of biodiversity is an equity issue; 70% of people living in poverty rely on natural resources for their livelihoods.

Current Pressures on Biodiversity

• Increasing pressures include habitat degradation due to agriculture and infrastructure development, overexploitation, pollution, invasive species, and climate disruption.

• These changes interact with one another leading to ongoing losses in populations, species diversity, and habitats.

Understanding One Health

• The "One Health" approach addresses interconnections between human health, animal health, and ecosystem health.

• Zoonotic diseases (e.g., COVID-19), which can be transmitted from animals to humans through various means are a growing concern linked to environmental changes.

Drivers of Environmental Change

• Key drivers include population growth, urbanization, economic development, technology advancements, and climate change impacting biodiversity negatively.

• Changes lead to loss of genetic diversity crucial for species survival while reshaping natural communities raises concerns about ecosystem stability.

Interconnections Between People and Ecosystems

• Human consumption patterns trigger indirect drivers like agriculture that exert direct pressure on biodiversity through habitat loss and pollution.

• Services provided by ecosystems include provisioning (food/medicine), regulating (climate regulation), supporting (nutrient cycling), and cultural services (recreational/aesthetic).

Future Predictions for Biodiversity

• Population growth will increase pressures on ecosystems; climate change is predicted to become the dominant driver affecting biodiversity in the coming decades.

• Addressing these pressures requires tackling the underlying drivers such as land use change and pollution.

Global Environmental Pressures and Their Impacts

Overview of Global Threat Distribution

• The global distribution of environmental threats varies, with areas marked in red indicating very high threat intensity and orange showing high threat intensity. This can be referenced in the provided figure.

• A significant portion of critically endangered, endangered, and vulnerable species among mammals, birds, and amphibians is attributed to land use change and habitat loss, represented in dark green on the graph.

Major Environmental Pressures

• Invasive species are depicted in lighter shades of green alongside pollution; over-exploitation is shown in black as a major threat factor. Atmospheric warming and extreme events are indicated in grey.

• Land use change refers to alterations made to existing land cover for various purposes such as urbanization, industrial development, infrastructure expansion, mining, and agriculture. These changes significantly increase human footprints on natural areas leading to desertification and deforestation.

Human Impact on Ecosystems

• Land use changes adversely affect both aquatic and terrestrial environments by exposing them to pollution and pathogens that can lead to emerging infectious diseases affecting humans, livestock, and wildlife. Additionally, these changes contribute to increased human conflict over resources.

• The 2009 global human footprint map illustrates combined pressures from infrastructure development and land cover changes; regions highlighted in red indicate severe degradation while green zones show improvement areas. Attention is drawn specifically to India’s footprint changes based on this study.

Invasive Species: Threats to Biodiversity

• Development often coincides with biodiversity hotspots due to inadequate planning; road construction facilitates the spread of invasive species into previously intact habitats which increases exposure to hunting threats and resource exploitation.

• Invasive species disrupt ecosystems through direct competition or predation; they may also cause habitat degradation or hybridization between different species which can threaten native biodiversity significantly.

Health Risks Associated with Invasive Species

• Invasive plants can compromise key ecosystem services essential for human health; certain invasive invertebrates pose heightened risks due to their rapid population expansions impacting local ecosystems severely (e.g., Zebra Mussels).

• Specific examples include invasive pests like Gypsy Moth and Emerald Ash Borer that have detrimental effects on biodiversity as well as economic implications following their introduction into North America via accidental means (e.g., cargo imports).

Conclusion: Broader Implications of Environmental Changes

• The introduction of invasive insect vectors has been linked with the spread of infectious diseases such as Chikungunya, Dengue, and Zika virus transmitted by mosquitoes; this highlights the interconnectedness between environmental management practices and public health outcomes amidst ongoing climate change challenges.

Impact of Climate Change on Biodiversity

Extreme Weather Events and Habitat Loss

• The increasing frequency of extreme weather events, such as hot summers, heavy rains causing floods, droughts, and forest fires, contributes to habitat loss and degradation of already stressed habitats.

Effects of Rising Temperatures

• Warmer seas due to increased temperatures are reducing sea ice extent, affecting critical hunting habitats for polar bears, seals, and fishing birds according to the IPCC report.

Atmospheric Changes and Ecosystem Services

• Increased atmospheric carbon dioxide leads to ocean acidification; this loss of wild species' habitat affects ecosystem services like pollination and pest control in agriculture.

Impact on Indigenous Communities

• Habitat loss obstructs indigenous communities' access to nature, resulting in significant economic costs related to conservation efforts that can reach billions annually.

Pollution: A Major Driver of Biodiversity Loss

Types of Pollution

• Pollution manifests in various forms including waste and chemicals released into the environment. Major sources include transport, industry, agriculture, and aquaculture.

Soil and Water Pollution

• Land soil pollution disrupts microbial populations essential for ecosystem functioning. Water pollution from plastics and chemicals threatens wildlife across marine and freshwater environments.

Air Pollution Effects

• Air pollution contributes to acidification and eutrophication in ecosystems like lakes and coastal waters while also leading to mercury bioaccumulation in aquatic food webs.

Overexploitation: Threatening Species

Illegal Activities Impacting Biodiversity

• Overexploitation through illegal activities such as unregulated fishing or logging poses threats to both land and marine species.

Socioeconomic Implications

• The overexploitation deprives vulnerable local communities—especially indigenous peoples—of resources necessary for sustenance, traditional medicines, tourism income, and other ecosystem benefits.

Climate Change Drivers Affecting Biodiversity

Anthropogenic Climate Change Effects

• The impacts of climate change on biodiversity are evident; reports suggest up to one in six species could face extinction by 2050 if current warming trends continue.

Species Adaptation Responses

• In response to rising temperatures, species may migrate towards cooler areas or alter their breeding patterns. Evidence indicates they are adapting through both movement and phenological changes.

Global State of Biodiversity Trends

Negative Impacts Across Dimensions

• Global changes negatively impact all dimensions of biodiversity—from genetic diversity down to entire ecosystems—though measuring genetic diversity remains challenging due to limited baseline data.

Importance of Genetic Diversity

• Genetic diversity is crucial for the adaptation of wild species through natural selection; it supports agricultural resilience which is vital for food security.

Decline of Biodiversity and Its Impacts

Overview of Biodiversity Decline

• The global decline in crop varieties and livestock breeds indicates a significant loss of biodiversity, as highlighted by the International Union for Conservation of Nature (IUCN).

• The IUCN Red List shows critically endangered species, with cycads being the most threatened and reef-forming corals classified as vulnerable.

• Anthropogenic land use changes have led to a marked decline in biodiversity from 1970 to 2014, affecting various species globally.

Vegetation Productivity and Ecosystem Threats

• A study reveals a decrease in vegetation productivity between 2000 and 2013 due to human activities, with 34% of terrestrial ecoregions at risk.

• Natural wetland areas have seen an average decline of about 30% from 1970 to 2008, exacerbating threats to marine ecosystems.

Impact on Global Biomes

Definition and Importance of Biomes

• Biomes are major ecological communities adapted to specific climatic conditions across large geographical areas. They encompass diverse ecosystems that support Earth's biodiversity.

Ocean and Coastal Ecosystems

• Open ocean biodiversity faces pressures from overexploitation, pollution, and climate change; coastal ecosystems suffer from habitat destruction and invasive species.

• Coral reefs are among the most biodiverse yet vulnerable marine ecosystems experiencing significant declines.

Freshwater Systems

• Freshwater systems face multiple pressures leading to an alarming average decline of 81% in freshwater vertebrate species over the past four decades.

• Approximately one-third of over seven thousand freshwater invertebrate species on the IUCN Red List are considered threatened, highlighting their critical role in ecosystem services.

Grasslands and Agricultural Landscapes

Grassland Ecosystems

• Grasslands cover about 8% of total land area but are now endangered due to land use changes, overgrazing, fragmentation, invasive species, climate change, and afforestation efforts.

Agricultural Expansion Effects

• Agricultural expansion has historically led to biodiversity loss; however, some practices can maintain rare species within semi-natural habitats.

Dry Lands: Challenges and Resilience

Characteristics of Dry Lands

• Dry lands contain resilient species adapted to harsh environments but face degradation due to human conflicts and unsustainable practices.

Consequences of Degradation

• Desertification impacts freshwater availability and food production while threatening genetic resources essential for survival.

Impact of Environmental Changes on Biodiversity

Effects of Desertification and Deforestation

• Desertification leads to soil health degradation and vegetation loss, resulting in salinization, which poses significant challenges in affected biomes.

• The primary drivers of deforestation include biomass demand, urban expansion, agriculture, energy mining, and transportation development.

• Deforestation has direct health consequences affecting both physical and mental well-being; it increases exposure to infectious diseases like malaria.

Mountain Ecosystems Vulnerability

• Mountain ecosystems cover 22% of terrestrial space and are crucial for biodiversity; however, they face habitat degradation and fragmentation.

• Climate change significantly impacts mountain ecosystems by altering species ranges and ecosystem functioning.

• Most mountain areas are under human pressure; the Himalayas alone host approximately 19,000 vulnerable species due to climate change.

Consequences of Biodiversity Loss

• Loss of biodiversity in mountains affects air quality, climate regulation, food security, medicinal plants availability, water quality, and increases risks associated with landslides and flooding.

• Glacier loss threatens water security for populations reliant on Himalayan river flows.

Challenges in Polar Regions

• The polar regions act as sinks for anthropogenic pollutants but face stress from rising temperatures and invasive species.

• Predictions indicate that the Arctic may be ice-free by 2050; this will lead to major ecological shifts impacting native species like penguins.

Summary of Key Concepts Discussed

• Today's session covered the meaning of biodiversity along with issues such as mass extinction threats and the concept of One Health.

• Emphasis was placed on understanding interconnections between people, biodiversity, ecosystem health, and environmental impact assessments.

• The discussion highlighted various world biomes' conditions while stressing the importance of assessing environmental impacts comprehensively.