Threats to Biodiversity

Threats to Biodiversity

1. Pollution

   • -Humans depend on nature to dispose of our waste products. -This can overwhelm the Earth's capacities to absorb, transform or break down these materials. -Can become more toxic as they decompose, resulting in long-term environmental damage. -Pollutants dumped into the environment don't just disappear, or remain suspended in air or water; they enter the tissue of the living things. -These are passed up through the food chain in a process known as bioaccumulation. -E.g. Beluga whales at St. Lawrence River and dolphins in Taiji (Japan) are affected by PCB's, mercury and lead.

2. Overexploitation

   • -Unsustainable hunting, fishing or extracting raw materials. -Reduces the number of species and diminishes diversity within the gene pool. -Disrupts the interaction between species in the ecosystem. -E.g. Passenger pigeon and American buffalo. -It is rare for an animal to return to its historical abundance once it has experienced an abrupt decline. -Sustainable use of natural resources is essential to ensuring that future generations have the same quality of life that we have today.

3. Climate Change

   • -Accumulation of greenhouse gases in the atmosphere which may lead to the alteration of long-term weather patterns. -Includes more intense heat and cold in certain locations, and more extreme weather events such as floods, droughts and ice storms. Moisture and temperature are fundamental to the way organisms and ecosystems develop, climate change impacts may be the single greatest threat to biodiversity. -Climate change may cause local species loss as high as 20% in the most vulnerable arctic and montane habitats.

4. Habitat Loss, Degradation and Fragmentation

   • -Habitat destruction alters and potentially eliminates the conditions needed for plants and animals to survive. -Leaves isolated patches of ecosystems, disrupt pollination, seed dispersal, wildlife migration and breeding. -Humans cause the destruction of habitat by large scale industrial logging, conversion of land to agricultural use, urban sprawl and industrial accidents.

5. Industrial Logging

   • Everyday in British Colombia, coastal temperate forests - one of the most rare ecotypes - are being logged.

6. Conversion to Agriculture

   • -This removes native species and severely alters ecosystem processes, such as water filtration. -The UN Food and Agriculture Organisation (FAO) recently estimated the annual rate of loss of these ecosystems was nearly 2% by the end of the 1990s. -Much of the logging in tropical forests is done to create grazing areas for cattle.

7. Urban Sprawl

   • -Natural ecosystems are often most seriously affected by urban development. -Critical habitat is not just degraded habitat, it's obliterated. Urban sprawl may be the most important issue facing endangered species in the world.

8. Industrial Accidents

   • Leakages from mining tailing porids, nuclear waste facilities and chemical spills all pose significant problems and have the potential to severely damage a variety of ecosystems.

9. Habitat & Captive Breeding Projects

   • Some projects call for the restoration of endangered species devastated by habitat loss through captive breeding projects. Although some have been encouraging, these programes must be supported by habitat protection. Without adequate habitats, these creatures can't survive. 

10. Invasive Species

    • -Biologists believe that invasive species are a major cause of global species extinction. -Some invasive species are brought intentionally as ornamental plants and pets, E.g. English ivy. -Many invasive species, such as the Zebra mussel, arrive by accident. This highly invasive mussel has severely impacted the lake's food web by reducing phytoplankton abundance and has almost eliminated some native clam species. -Invasive species can carry disease and compete for habitat. -Invasive plant species tend to do especially well in disturbed environments, which further clarifty the need to preserve our remaining ecosystems. -Recent effort to remove this invasive plant (rhododendron) has cost tens of millions of dollars, leaving behind soils which will not de-toxify for another 5-10 years.