Biodiversity loss refers to the decrease or disappearance of biological diversity, understood as the variety of living beings that inhabit the planet, the different levels of biological organization -plants, animals, fungi, microorganisms, and their respective genetic variability- as well as the natural patterns present in ecosystems.
The loss of biodiversity is so severe that it is considered the «Sixth Mass Extinction» with extinction rates 100 to 1000 times higher than those considered natural, one of the aspects that characterize the Anthropocene.
It is estimated that by the year 2100, land-use change, climate change, modification of the nitrogen cycle and invasive species will be the main drivers of global biodiversity loss; the first three factors are also planetary boundaries.
The aforementioned elements, as well as the legal and illegal exploitation of wild species, can be considered the direct causes of biodiversity loss (the immediate physical actions or processes that give rise to it), but it is important to point out that there are also indirect or underlying causes, i.e. the fundamental forces that operate diffusely on the direct causes and are made up of a complex of social, political, economic, demographic, technological and cultural variables.
Main causes of biodiversity loss:
- Changes in land use (e.g. deforestation, intensive monoculture, urbanization).
- Direct exploitation such as hunting and overfishing.
- Climate change.
- Pollution.
- Invasive alien species.
What are the causes of biodiversity loss?
When we talk about biodiversity, we refer to the living beings of the planet (human beings and animals), the ecosystems that make up the forests and jungles, and the rivers and seas of the water ecosystem.
That is why biodiversity generates balance in the world and is so important in the nutrition of human beings because that is where they get food, water, raw materials, and natural resources essential for life.
In contrast, the loss of biodiversity is detrimental to the quality of life of humans, animals, and plants.
The main consequences include the extinction of species, pollution of rivers and seas, increased carbon dioxide emissions, continuous alterations of the climate, soil erosion due to drought, and the destruction of the natural ecosystem.
The causes of biodiversity loss can be listed as follows:
Overexploitation of nature
For many decades, ecologists have been warning about the way in which man has made a thoughtless and uncontrolled use of nature in all its manifestations by extracting its resources more progressively than the capacity of ecosystems to regenerate.
For many decades ecologists have been warning about the way in which man has made an inconsiderate and uncontrolled use of nature in all its manifestations by extracting its resources more progressively than the capacity of ecosystems to regenerate.
These activities are expressed especially in hunting, fishing, indiscriminate logging, illegal trade of species, burning, and mining that puts man’s greed before the preservation of nature.
In this way, impressive natural ecosystems have been destroyed, such as the forests or the forests of the Amazon, where many of their hectares have been transformed into desolate fields to the detriment of the indigenous people and animals that inhabit them so that many species are threatened with extinction or have become extinct..
In the ecosystem is the case of the Polar bear endangered by the destruction of glaciers due to climate change and the danger of extinction of some shark species, such as the great white shark in Steven Spielberg’s movie; the otter, whales, etc.
Continued habitat aggression
Of course, this constant human action causes total or partial loss of the habitats of the creatures that live in them.
This also contributes to the extinction of some species because they begin to feel strange in their semi-destroyed or transformed natural environments, and have to look for other spaces that are not their own, which causes disturbances in them, if not death.
Man, in his excessive search for wealth, incurs arbitrariness against nature, modifying the natural course of rivers, destroying or transforming forests or jungles, thus contributing to the loss of biodiversity.
This action produces the so-called «edge effect», which occurs when species from two different habitats come into contiguous contact in the same ecosystem, leading to changes in environmental and biological conditions.
Two of the examples given in this regard are a forest fire or the construction of a road in the middle of a forest, which is considered to be one of the main causes of species extinction.
Environmental pollution
Environmental pollution can have natural causes, but in its most serious expression, it is produced as a consequence of human activity.
The harmful alteration of ecosystems often occurs due to the presence of pollutants in water, air, and soil. Ecosystems are frequently altered by the presence of pollutants in water, air, and soil.
These pollutants in the form of chemicals are discharged into waters or dispersed into the air by humans, which inexorably contributes to the loss of biodiversity. Among them, we can mention fertilizers and pesticides, plastic materials, and waste from industrial activities.
But the greatest pollution of the environment occurs due to the effect of burning fossil fuels that produce an acid rain of sulfur and carbon dioxide (CO2) which greatly affects the various ecosystems, as it suffocates the plants in such a way that prevents them from releasing oxygen, and we know that without oxygen we cannot live.
The emission of carbon dioxide into the environment, which has doubled in recent decades, causes an excess of temperature or global warming which is climate change.
Fossil fuels are four: oil, coal, natural gas, and liquefied gas, which, as the new horsemen of the Apocalypse, have become the great enemies of biodiversity, because of the damage they cause.
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Climate change
Climate Change, according to the United Nations, is the variation of the Earth’s climate, due to human activity, which alters the composition of the global atmosphere.
It manifests itself especially in the emission of fossil fuels, as carbon dioxide is responsible for 63% of global warming.
In fact, Climate Change is the origin of the destruction of the ozone layer and produces high temperatures, cloudiness, precipitation, and, with it, deadly diseases of humans, animals, and plants, floods, and melting of the poles.
Noise pollution
High sound levels in cities produce noise pollution that scares animals, especially those with sensitive ears such as rodents, bats, and owls, and makes birds migrate because it prevents them from communicating.
High sound levels in cities produce noise pollution that scares animals, especially those with sensitive ears such as rodents, bats, and owls, and causes birds to migrate because it prevents them from communicating.
Light pollution
The intensity of artificial lighting causes changes in the biorhythms of some species and sometimes confuses species that do not distinguish day from night.
Thermal pollution
Thermal pollution occurs when heat is introduced into the environment in an uncontrolled manner and is caused by the discharge of hot water into rivers and lakes, greenhouse gases, and sudden temperature change.
Due to thermal pollution, oxygen levels in the environment decrease, producing an increase of toxins, especially in rivers and seas, which considerably affects species. Due to thermal pollution, oxygen levels in the environment decrease, producing an increase of toxins, especially in rivers and seas, which considerably impacts species.
Invasive species
Invasive species cause serious alterations in the way of life of other species by displacing them from their natural habitat. Invasive species cause serious alterations in the way of life of other species by displacing them from their natural habitat.
The invasion can be voluntary or programmed and has been increasing considerably, making it one of the causes of biodiversity loss, because native species can die out and become extinct.
Illegal hunting
Illegal hunting is one of man’s predatory activities against biodiversity because many animals have become extinct or are in danger of extinction due to this unhealthy unnatural practice..
It is so serious that most countries in the world have signed a treaty called the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) that seeks to stop the hunting of species in danger of extinction.
Despite the measures that have been taken, poaching continues, because this is a very lucrative activity for the horns, ivory, and skin of some animals, such as elephants, which are in serious danger of extinction.
This business is not only occurring in Africa and Asia but extends to all national parks around the world, where species protection measures have had to be taken to the extreme.
The deforestation and mining
The home of thousands of animals is destroyed by deforestation, mining, intensive agriculture, and cattle ranching, which transform the ecosystems by attacking the flora, thus causing the eviction of many species from their natural habitats.
Logging, burning, construction in natural areas, the proliferation of polluting industries, all of these are a set of actions that conspire against biodiversity in the world.
Mining, due to the use of mercury, pollutes rivers and destroys hundreds of hectares of forests, as occurs in the so-called Orinoco Mining Arc, which occupies an area of almost 112 thousand km2, in southern Venezuela, where the government has legalized the exploitation of RORO and coltan.
Despite complaints from environmentalists about the environmental and socio-cultural impact and the violation of the rights of the indigenous communities in the region. The Orinoco project has been legalized by the government.
Deforestation, intensive agriculture, and cattle ranching: the transformation of ecosystems very rich in biodiversity, such as jungles, into large agricultural and cattle ranching extensions destroys the natural home of thousands of animal and plant species.
Ocean acidification
This phenomenon occurs because the increase of CO2 in the ocean lowers the pH levels of the sea surface, increasing its acidity. Since pre-industrial times, the pH at the ocean surface has decreased by about 0.1 pH units (corresponding to a 30% increase in hydrogen ion concentration and a 16% decrease in carbonate concentrations).
Acidification affects multiple organisms with calcium carbonate structures, whose shells or skeletons are at risk of dissolvings, such as pteropods, coral reefs, and plankton, which in turn would affect marine food webs.
With decreasing pH, coral reefs are at risk of being exposed to marginal conditions, which could lead to substantial changes in species composition, as well as in the dynamics of corals and other reef communities.
Moreover, as ocean acidification and global warming combine and interact, they decrease productivity in coral reefs.
Alteration of the nitrogen and phosphorus cycles
Reactive nitrogen synthesized by humans – accumulated in terrestrial systems, or in the form of greenhouse gases (GHGs) (in the form of nitrous oxide N2O) – pollutes coastal zones, causes acid rain5, and modifies the plant composition of biomes where it is the most limiting element.
While high levels of phosphorus in the ocean are related to major anoxic events that have led to mass extinctions of marine life.1
Invasion of alien species
Invasive Alien Invasive Species (IAS) represent one of the main threats to global biodiversity, being considered by some authors as the second greatest threat after habitat loss.
IAS displace native species through direct competition, predation, disease transmission, or habitat modification, which in turn can cause extinctions, degradation of aquatic and terrestrial ecosystems, and alteration of ecological processes and functions as well as biogeochemical cycles.
Island ecosystems are the most affected, as their high proportion of endemic species – lacking defense mechanisms against species with which they did not coevolve – makes them especially vulnerable, generating very short periods of extinction.
On islands, IAS is the leading cause of biodiversity loss, which is even more alarming if one considers that the extinction rate is 500 to 700% higher than on the mainland.
Species exploitation/illegal wildlife trafficking
In the case of marine fauna extinctions, the dominant driver of extinctions is not climate change or subsequent acidification, but human fishing. Therefore, the largest species are the most affected (with a 13 times greater probability of being under the threat of extinction), since fishermen obtain greater profits from them.
For its part, the United Nations Office on Drugs and Crime (UNODC) reported that from 1999 to 2015 there were 164,000 seizures from 120 countries of 7,000 species protected by the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES).
Mostly rosewood (35%), followed by elephants (18%), reptiles (9%), agarwood (6%), pangolin (5%), rhinoceroses and sea turtles (3% each), parrots, big cats, raptors, tortoises and freshwater turtles (2% each); coral and sturgeon (1%).
The above shows that species trafficking is a global problem, which is massacring populations, such is the case of the 100,000 elephants killed from 2010 to 2012, and rhino hunting in South Africa which increased 8,000% between 2007 and 2014.
Indirect causes
Impacts on biodiversity can be framed within the Anthropocene, the current geological era in which the human species determines the fundamental processes of the biosphere, leading to global environmental change. Virtually all aspects of global change are caused primarily by rapid human population growth and increased per capita resource consumption.
The latter is largely driven by the logic of the capitalist system that constantly seeks to create commodities to accumulate wealth, either by solving existing basic and historical-social needs or by creating new ones, regardless of the environmental costs and injustice to other animals and species.
It is possible to analyze indirect causes on a larger scale and identify key sectors in the direct causes of biodiversity loss, such as:
- Land-use change: cattle ranching, real estate developers, and road builders.
- Climate change and ocean acidification: power generation, agriculture -especially livestock-, industry, and transportation.
- Species exploitation/illegal wildlife trafficking: for food, medicinal, sporting, cosmetic, entertainment, ornamental, clothing, luxury goods7, and religious purposes.
- It is worth noting that animal food consumption (and therefore livestock and fisheries) is the main cause of modern species extinctions, being the major driver of habitat loss, the main cause of climate change, soil loss, overfishing, sedimentation of coastal areas, facilitation of invasions of exotic species, water pollution and decline of large predators and wild herbivores. Thus, the underlying causes of biodiversity loss are the hegemonic capitalist and anthropocentric production and consumption model, supported by governments and society in general. For a more detailed classification of the economic, technological, institutional, and cultural drivers of biodiversity loss, see Annex.
Me gusta colaborar con esta página porque desde bien joven me ha encantado el funcionamiento de la naturaleza y la biología. Tenía claro que quería estudiar algo relacionado con estos temas y por eso me acabé decidiendo por Biología.
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