Causes of Biodiversity Loss

Biodiversity loss is caused by five primary drivers:

• Habitat Loss: Habitat loss is the thinning, fragmenting, or outright destruction of an ecosystem’s plant, soil, hydrologic, and nutrient resources. 
• Invasive Species: An invasive species is any non-native species that significantly modifies or disrupts the ecosystems it colonizes. Invasive species can disrupt ecosystems because they are better competitors than native species; they may consume food resources more rapidly or more efficiently or take over habitats faster than native species can adapt to the new changes. Some invasive species prey on native species, and if the native species have no natural defenses against the invaders, they may be eliminated rapidly. 
• Overexploitation (overhunting and overfishing) is the process of harvesting too many aquatic or terrestrial animals, which depletes the stocks of some species while driving others to extinction.
• Pollution is the addition of unneeded or harmful nutrients or substances to an ecosystem. In a polluted area the quality of food, water, or other habitat resources declines, sometimes to the point where some species must move away or perish if the pressure is too great.
• Climate Change associated with Global Warming: 
• Global warming is the long-term increase in Earth’s average air temperature over the past one to two centuries. It can refer specifically to such warming that is due to the influence of rising concentrations of carbon dioxide, methane, and other greenhouse gases in the atmosphere. As the concentration of these gases increases, the ability of Earth’s atmosphere to retain energy from incoming sunlight also increases. With more heat available, once reliable temperature and rainfall patterns change, upsetting the natural order of breeding and resource availability. Also, ecosystems that rely on the presence of ice shrink as melting breaks them down. 
• Global warming itself does not necessarily produce biodiversity loss, but climatic changes (some of which are sudden and drastic) can modify ecosystems and the expectations of the species within them significantly.
• Ecologists emphasize that habitat loss (typically from the conversion of forests, wetlands, grasslands, and other natural areas to urban and agricultural uses) and invasive species are the largest causes of biodiversity loss, but they acknowledge that climate change could rival them as the 21st century progresses.

Effects of Biodiversity Loss

• Ecological effects:

  • The weight of biodiversity loss is most pronounced on species whose populations are decreasing. The loss of genes and individuals threatens the long-term survival of a species, as mates become scarce and risks from inbreeding rise when closely related survivors mate. The wholesale loss of populations also increases the risk that a particular species will become extinct.
  • Biodiversity is critical for maintaining ecosystem health. Declining biodiversity lowers an ecosystem’s productivityand lowers the quality of the ecosystem’s services.
  • Biodiversity loss also threatens the structure and proper functioning of the ecosystem. Although all ecosystems are able to adapt to the stresses associated with reductions in biodiversity to some degree, biodiversity loss reduces an ecosystem’s complexity, as roles once played by multiple interacting species or multiple interacting individuals are played by fewer or none. As parts are lost, the ecosystem loses its ability to recover from a disturbance. Beyond a critical point of species removal or diminishment, the ecosystem can become destabilized and collapse. That is, it ceases to be what it was and undergoes a rapid restructuring, becoming something else. 
  • Reduced biodiversity also creates a kind of “ecosystem homogenization” across regions as well as throughout the biosphere. Specialist species (i.e., those adapted to narrow habitats, limited food resources, or other specific environmental conditions) are often the most vulnerable to dramatic population declines and extinction when conditions change. On the other hand, generalist species (those adapted to a wide variety of habitats, food resources, and environmental conditions) and species favoured by human beings become the major players in ecosystems vacated by specialist species. As specialist species and unique speciesare lost across a broad area, each of the ecosystems in the area loses some amount of complexity and distinctiveness, as the structure of their food chains and nutrientcycling processes become increasingly similar.
• Economic and societal effects 
  • Biodiversity loss affects economic systems and human society. Humans rely on various plants, animals, and other organisms for food, building materials, and medicines, and their availability as commodities is important to many cultures. The loss of biodiversity among these critical natural resources threatens global food security and the development of new pharmaceuticals to deal with future diseases. Simplified, homogenized ecosystems can also represent an aesthetic loss.
  • Economic scarcities among common food crops may be more noticeable than biodiversity losses of ecosystems and landscapes far from global markets. 
  • Mainstream and traditional medicines can be derived from the chemicals in rare plants and animals, and thus lost species represent lost opportunities to treat and cure.

Solutions to Biodiversity Loss 

• Governments, non-governmental organizations, and the scientific community must work together to create incentives to conserve natural habitats and protect the species within them from unnecessary harvesting, while disincentivizing behaviour that contributes to habitat loss and degradation.
• Sustainable development must be considered when creating new farmland and human living spaces. 
• Laws that prevent poaching and the indiscriminate trade in wildlife must be improved and enforced. Shipping materials at ports must be inspected for stowaway organisms.
• Efforts that monitor the status of individual species, such as the Red List of Threatened Species from the International Union for Conservation of Nature and Natural Resources (IUCN) and the United States Endangered Species list remain critical tools that help decision makers prioritize conservation efforts. 
• In addition, a number of areas rich in unique species that could serve as priorities for habitat protection have been identified. Such “hot spots” are regions of high endemism, meaning that the species found there are not found anywhere else on Earth. Ecological hot spots tend to occur in tropical environments where species richness and biodiversity are much higher than in ecosystems closer to the poles. 
• Concerted actions by the world’s governments are critical in protecting biodiversity.
  • Numerous national governments have conserved portions of their territories under the Convention on Biological Diversity (CBD).
  • A list of 20 biodiversity goals, called the Aichi Biodiversity Targets, was unveiled at the CBD meeting held in Nagoya, Japan, in October 2010. The purpose of the list was to make issues of biodiversity mainstream in both economic markets and society at large and to increase biodiversity protection by 2020. Since 2010, 164 countries have developed plans to reach those targets.