Drivers of Biodiversity Loss (Leaving Cert CASD): Revision Notes
Drivers of Biodiversity Loss
What is biodiversity?
Biodiversity refers to the incredible variety of life on Earth. It includes all the different species of plants, animals, fungi, and tiny organisms like bacteria, along with the genetic differences within these species and the ecosystems they create together. Think of it as nature's amazing collection of living things and the environments they call home.
Biodiversity helps maintain the balance of nature and provides essential services that keep ecosystems healthy. These include processes like pollination, nutrient cycling, and climate regulation, plus resources we depend on daily like food, materials, and medicines.
The three levels of biodiversity
Scientists organise biodiversity into three main categories:
-
Genetic diversity: The differences in genetic makeup between individuals within the same species. This variation helps species adapt to changing conditions and survive threats.
-
Species diversity: The variety and number of different species living in a particular ecosystem or across the entire planet. More species generally means a healthier, more stable ecosystem.
-
Ecosystem diversity: The range of different ecosystems (like forests, grasslands, wetlands, and coral reefs) and the ecological processes that occur within them.
Factors that shape biodiversity
Several environmental factors influence where and how biodiversity develops. Geographical location and landscape features play crucial roles in determining which species can survive in different areas.
For example, islands often have unique species because they've been isolated for long periods. Mountain regions support different ecosystems at various elevations, whilst coastal areas face challenges from salt water and erosion that inland areas don't experience. These natural variations help explain why some regions have much richer biodiversity than others.
Current state of global biodiversity
The situation facing our planet's biodiversity has never been more serious. Current research shows that we're experiencing unprecedented rates of species loss, with biodiversity decline ranking among the most critical global challenges we face today.
Recent studies reveal alarming trends: approximately 28% of all assessed species worldwide are now threatened with extinction. The situation in Europe is equally concerning, with 25% of assessed species classified as endangered. These figures represent more than just statistics – they indicate a fundamental crisis affecting the natural systems that support all life on Earth.
Despite increased awareness and conservation efforts over recent decades, traditional approaches to preventing biodiversity loss have proven insufficient. With over one million species currently at risk of extinction – many potentially disappearing within decades – the urgency for comprehensive action has never been greater.
Why is biodiversity declining?
Climate change impacts
One of the primary reasons for biodiversity decline is ongoing climate change, which is gradually transforming ecosystems worldwide. As temperatures rise and weather patterns shift, the natural processes, functions, and services that ecosystems provide are also changing dramatically.
Urban environments face particularly severe impacts. Cities already struggle with heavy pollution and fragmented green spaces, making their ecosystems especially vulnerable. The large areas of concrete and asphalt in urban areas make extreme weather events like heavy rainfall, heat waves, and droughts even more damaging to the remaining biodiversity.
Main drivers of biodiversity loss
According to leading scientific research, five key factors directly drive most biodiversity loss worldwide: changes in land and sea use, overexploitation of natural resources, climate change, pollution, and invasive alien species. These drivers often work together, creating complex challenges for conservation efforts.
Behind these direct causes lie deeper issues including unsustainable consumption patterns, population growth, governance problems, and economic systems that don't properly account for environmental costs.
Land and sea use changes
Habitat destruction and conversion represents one of the most significant threats to biodiversity globally. When forests, wetlands, and other natural habitats get converted into agricultural land, urban areas, or infrastructure projects, entire ecosystems disappear along with the species that depend on them.
This process doesn't just remove habitats completely – it also creates habitat fragmentation, breaking large natural areas into smaller, disconnected patches. These fragmented habitats often cannot support the same diversity of species as intact ecosystems, leading to further losses over time.
Marine environments face similar pressures through unsustainable coastal development, deep-sea mining, and destructive fishing practices that damage ocean ecosystems and the countless species they support.
Resource overexploitation and pollution
Overuse of natural resources occurs when we extract materials from nature faster than ecosystems can regenerate them. This excessive harvesting leads to rapid depletion of wildlife populations and destruction of critical habitats. Current species loss rates are tens to hundreds of times higher than natural background rates, demonstrating the unsustainable pace of resource extraction.
Pollution from multiple sources severely damages both land and water ecosystems. Industrial activities, agriculture, and urban development release various pollutants including plastics, pesticides, and excess nutrients that harm wildlife and disrupt natural processes. In the European Union alone, nitrogen pollution costs an estimated €70-320 billion per year in environmental damage.
Climate change and invasive species interactions
Climate change and biodiversity loss create a dangerous feedback loop. As global temperatures rise and weather patterns become more extreme, ecosystems lose their ability to regulate climate naturally. Healthy ecosystems like forests, wetlands, and coral reefs normally help control carbon storage and climate patterns, but biodiversity loss weakens these natural climate solutions.
Invasive alien species pose another major threat, whether introduced intentionally or accidentally. These non-native species can outcompete or directly harm native wildlife, particularly in vulnerable ecosystems like islands and freshwater systems. The annual cost of invasive species damage in the EU is estimated at around €12 billion, highlighting the scale of this problem.
Biodiversity and human wellbeing
Essential ecosystem services
Ecosystems provide numerous vital services that human societies and economies depend on completely. These ecosystem services ensure our access to clean water and air, food production, medicines, and raw materials. They also contribute to climate regulation, water purification, and natural pollination of crops.
Natural landscapes and wildlife provide cultural benefits too, inspiring tourism, recreation, and holding deep spiritual significance for many communities and indigenous peoples. Ecosystem services are also crucial for disease control and natural disaster risk management.
The Four Types of Ecosystem Services:
Scientists categorise ecosystem services into four main types:
-
Supporting services: Basic ecological processes like oxygen production, photosynthesis, soil formation, and nutrient cycling that support all other services.
-
Regulating services: Natural processes that control environmental conditions, including climate regulation, flood prevention, erosion control, and pest control.
-
Provisioning services: Direct products from nature such as food, fresh water, timber, fibres, medicines, and energy sources.
-
Cultural services: Non-material benefits including recreation, spiritual and aesthetic values, cultural identity, and educational opportunities.
Economic implications
The economic consequences of biodiversity loss are staggering. Conservative estimates suggest that ecosystem service collapse could reduce global GDP by nearly €2.6 trillion by 2030, with low-income and middle-income countries facing particularly severe impacts.
Many businesses rely directly on healthy ecosystems for services like soil quality, crop pollination, pest control, and genetic resources. Ecosystems also provide natural protection against disasters, helping reduce economic losses from environmental events.
As ecosystems become degraded or used unsustainably, the risk of sudden, potentially irreversible changes increases dramatically. These changes could reduce availability of essential services like clean air, water, food, and natural climate regulation, while weakening ecosystem resilience to environmental changes including climate impacts.
However, transitioning to a nature-positive economy represents a major business opportunity. By 2030, solutions that improve nature's condition could create 395 million new jobs and generate nearly €10 trillion worth of business value globally, demonstrating that protecting biodiversity can drive economic growth while safeguarding our planet's resources.
Key Points to Remember:
-
Biodiversity operates at three levels: genetic diversity within species, species diversity within ecosystems, and ecosystem diversity across landscapes
-
Five main drivers cause biodiversity loss: land and sea use changes, resource overexploitation, climate change, pollution, and invasive alien species
-
Current species extinction rates are 10-1000 times higher than natural rates, with 28% of assessed species globally threatened with extinction
-
Climate change and biodiversity loss reinforce each other – healthy ecosystems help regulate climate, while climate change accelerates biodiversity loss
-
Ecosystem services provide trillions of euros worth of benefits annually through supporting human health, economic activity, and environmental stability