Threat to biodiversity

The Convention on Biological Diversity recognises five major threats to biodiversity, which are generally recognised in its work programs: invasive alien species, climate change, nutrient loading and pollution, habitat change, and overexploitation. Unless we are successful in mitigating the effects of these direct drivers of change on biodiversity, they will contribute to the loss of biodiversity components, negatively impact ecosystem integrity, and obstruct efforts to achieve sustainable use of resources.

Remember that, behind these direct drivers of biodiversity loss, several indirect drivers interact in complex ways to cause human-induced changes in biodiversity. This is especially true when discussing climate change and biodiversity. Factors that influence human activities that have a direct impact on biodiversity include those related to demographics, economics, sociopolitical factors, culture, religion, science, and technology, among others.

In the context of the focal area addressed here, indicators for trends in nutrient loading and invasive alien species have been identified, and they are described in greater detail below. The indicator trends in the extent of selected biomes, ecosystems, and habitats provide information on the changing nature of the environment. Aspects of overexploitation are discussed in the context of the focal area on sustainable use. Even though there is no single indicator of climate change’s impact on biodiversity, there are several indicators that can be used to derive trends in a variety of areas, such as trends in the extent of selected biomes, ecosystems, and habitats (particularly those applied to coral reefs, polar ice, and glaciers, as well as certain types of forests and drylands), the abundance and distribution of selected species, and the incidence of human-induced ecosystem failure in areas where specific data is available. The trend in the connectivity/fragmentation of ecosystems provides an indicator of the vulnerability of ecosystems to climate change because small, fragmented ecosystems are more affected by changes in temperature and humidity than large contiguous ecosystems with a more balanced micro-climate.

What is the impact of human activities on the amount of nitrogen present in the environment?

Several factors, including the availability of fertilisers on a commercial scale, have contributed to agriculture’s ability to produce far greater quantities of food and fibre than it has in the past. Extremely high concentrations of the plant nutrients nitrogen and phosphorus in natural ecosystems, on the other hand, are now causing concern. While reactive nitrogen occurs naturally in all ecosystems, the production of reactive nitrogen by humans, primarily to increase agricultural production through the manufacture of synthetic fertiliser, has altered ecological balances both locally and in far-flung ecosystems around the world. In response to human-caused production of reactive nitrogen, nitrogen compounds are released into the atmosphere, where they are then deposited into the biosphere. Nitrogen levels in ecosystems are raised as a result of increased atmospheric deposition of nitrogen, and slow-growing species that thrive in nitrogen-deficient environments are unable to compete with faster-growing species that require higher nutrient levels. Temperate grasslands, in particular, are particularly vulnerable in this regard. More significantly still, soluble nitrogen is leaching from soils into groundwater, contributing to increased eutrophication (excess nutrients in inland and coastal waters that stimulate excessive plant growth), algal blooms, and the formation of anoxic (oxygen-free) zones in inshore marine environments. 

How serious is the threat posed by invasive alien species to the preservation of biodiversity?

Alien species that invade and colonise new territory can have devastating effects on the local biota, leading to the extinction of native species and the disruption of natural and cultivated ecosystems. The introduction of invasive alien species has been linked to nearly 40% of all animal extinctions that have been traced back to their origins since the 17th century. In South Africa’s Fynbos biome, 80 percent of the threatened species are threatened or endangered as a result of the invasion of alien species.

A significant proportion of invasive alien species are significant pests or pathogens that can result in significant economic losses. Over US$ 100 billion is estimated to be lost annually to the environment as a result of introduced pests in the United States, the United Kingdom, Australia, South Africa, India, and Brazil, according to estimates. The presence of invasive alien species in an ecosystem has the potential to alter the structure and species composition of the ecosystem by suppressing or eliminating native species. Because invasive species are frequently just one factor in a complex set of factors affecting a particular site or ecosystem, it is not always straightforward to determine what proportion of the impact can be attributed to the species in question. In recent years, the rate and risk associated with alien species introductions have increased significantly, owing to the rapid increase in human population and the intensification of human activities that alter the environment, as well as the increased likelihood of species spreading as a result of increased travel, trade, and tourism.

Another important source of marine alien species introduction is hull fouling, which occurs when ships discharge ballast water into the ocean. Other sources of marine alien species introduction, such as aquaculture and aquarium releases, are also significant and less well regulated than ballast water. The movement of non-native species through the marine ecosystem has been extensively researched. 75 percent of the 150 species that have recently arrived in the Great Lakes are thought to have originated in or near the Baltic Sea. In a similar vein, the flow of migration from the Red Sea to the Mediterranean through the Suez Canal has continued unabated, with nearly 300 species of Lessepsian migrants, including decapod crustaceans, mollusks, and fishes, having entered the Mediterranean since 1891.

Conclusion:

Biodiversity is the variety of living things. It means the many forms of life that exist in a given area and on the planet overall, and how that life is supported. An area with good biodiversity will have many different forms of life in it: animals, plants, fungi, and others. These diverse species are all linked to each other in a network called an ecosystem.  

Different types of ecosystems support business sectors ranging from food and clothing to insurance and tourism. Economists call the economically valuable goods and services that ecosystems supply “ecosystem services”. These services include crop pollination, flood protection, and water purification. When there is enough biodiversity to keep these ecosystems working well, they can provide trillions of dollars worth of services every year.