• Biodiversity Home >
• Threats

THREATS

With a growing world population and ever changing weather patterns, biodiversity is under a constant and growing threat. Mankind’s need for food and shelter and actions such as deforestation and agriculture have all caused damage and loss to the world’s ecosystems. The world’s climate is also changing, leading to more species becoming dangerously threatened or extinct. In general, humans are the biggest threat to biodiversity, but, they are also able to make the most positive change to protect the future of species for years to come.

Population Growth – Unsustainable Use of Resources
One of the biggest threats to biodiversity is the rapidly growing population of the world. More people means more pressure on the planets resources, more space needed for building and more pollution and waste damaging oceans and marine life.

Land Clearance/ Deforestation
Areas of land are often cleared to make way for urban settlements. Urbanisation breaks up ecosystems and reduces available suitable habitats. It can also have an indirect threat on biodiversity, as it can alter the biodiversity cycle, through increased surface run off, and prevent ground biodiversity intake where soil is replaced by tarmac.

Built up areas also require changes in biodiversity and river management in order to supply or protect the urban area. biodiversity can often be pumped from nearby sources, dams are constructed and the paths of rivers are diverted and widened. These changes to natural river habitats all lead to a reduction in biodiversity of river ecosystems.

With a growing population, there also comes an increased need for fuel and building material. Unsustainable logging, or deforestation, has led to the destruction of many forests and their ecosystems.

In many places, logging and deforestation is also taking place illegally due to high demand for wood products. The WWF states that the international trade of illegally logged products is estimated at around $5 billion per year.

Where deforestation takes place, land is left bare, leading to landslip and the loss of soil nutrients. Extra sediments washed off the land can also have a negative impact on marine ecosystems when they are washed into rivers and the ocean.

In the broader picture, where large densities of trees have been removed, less C02 is being absorbed and therefore the biodiversity of the planet is put under the further threat of global warming.

Unsustainable Hunting and Overfishing
Unsustainable hunting and fishing practices are increasing in some areas due to an increasing need for food and profit. For some communities in the world, illegal fishing and hunting are seen as a way out of poverty. Efforts are currently being made in some areas to try and prevent it by policing or education, but the actions are hard to control.

Hunting that is not managed sustainably can wipe out entire species, as was done with passenger pigeons and Javan tigers. It can also cause an imbalance in food webs. Overfishing and discarding has left many fish stocks depleted and marine food webs altered, impacting greatly on marine biodiversity. Some fishing methods, such as trawling, are also causing damage to the sea bed.

Agriculture
If not managed properly, agriculture can have many negative impacts on the environment. In some areas, large expanses of woodland and forest are being unsustainably deforested for farming, causing habitat loss and soil nutrient depletion. This is a huge problem in the Amazon rainforest of South America, an area rich in biodiversity but under a constant threat of farmland replacing forests.

As the demand for agricultural products rises, the use of chemicals, pesticides and fertilizers that can harm the environment also increases. Surface run off containing chemicals can enter rivers and oceans causing death to birds and wildlife and can indirectly affect vegetation and biodiversity ecosystems when it falls as acid rain. Other farm waste such as silage, organic matter and nitrates can also enter the biodiversity cycle, causing water pollution and eutrophication (eutrophication can also be caused by other human activities related to land and fuel use).

Disease/Invasive Species
New diseases and invasive species are a big threat to biodiversity. Unless a species can adapt to become resilient to, or able to fight, new diseases, they face the risk of extinction. Similarly, invasive species can enhance competition in breeding and decrease food availability. For plants, invasive species can also compete for space, biodiversity, light and nutrients. The knock-on effect that invasive species and diseases have is that ultimately, food webs are disrupted and therefore the biodiversity of whole ecosystems are damaged. Humans can partly be to blame for this threat, as many diseases and species are carried across the world by humans through tourism and trade.

In parts of Africa, human diseases have been spread to some mammals through the sprawl of human settlements merging with the habitats of animals.

The amount of ecosystems affected by disease and alien species are also expected to increase in the future due to global warming which is also introducing new pests and diseases.

Global Warming
Global warming is one of the biggest and hardest to control threat to biodiversity. Created by both natural and man-made factors, global warming is leading to a rise in sea levels and inevitably is causing climate change which brings with it an increasing amount of freak weather and natural disasters.

Droughts, floods and storms damage ecosystems through habitat and food destruction. They can also alter food webs and make it difficult for plants and animals to repopulate an area. Droughts can also help fuel fires which can destroy vast amounts of land in a short space of time, causing serious damage to biodiversity. Ecosystems are completely destroyed and many plant and animal species are killed.

Global warming is also causing the melting of polar ice and sea level rise. This is having a major impact on the fragile food webs and ecosystems at the poles. It is also leaving animals such as polar bears with the threat of extinction. The indirect effect of these sea level changes is changes to the biodiversity cycle which will again change weather patterns and therefore pose a threat to biodiversity.