Biodiversity - Human Impacts

Biodiversity is the biological variety and variability of life on Earth. Biodiversity is a measure of variation

at the genetic, species, and ecosystem levels. Terrestrial biodiversity is usually greater near the equator, which is the result of the warm climate and high primary productivity. Biodiversity is not distributed evenly on Earth and is richer in the tropics. These tropical forest ecosystems cover less than ten percent of the earth's surface and contain about ninety percent of the world's species. Marine biodiversity is usually higher along coasts in the Western Pacific, where sea surface temperature is highest, and in the mid-latitudinal band in all oceans. There are latitudinal gradients in species diversity. Biodiversity generally tends to cluster in hotspots, and has been increasing through time, but will be likely to slow in the future as a primary result of deforestation. It encompasses the evolutionary, ecological, and cultural processes that sustain life.

The period since the emergence of humans has displayed an ongoing biodiversity reduction and an accompanying loss of genetic diversity. Named the Holocene extinction, the reduction is caused primarily by human impacts, particularly habitat destruction. Conversely, biodiversity positively impacts human health in a number of ways, although a few negative effects are studied.

The United Nations designated 2011–2020 as the United Nations Decade on Biodiversity. and 2021–2030 as the United Nations Decade on Ecosystem Restoration, According to a 2019 Global Assessment Report on Biodiversity and Ecosystem Services by IPBES 25% of plant and animal species are threatened with extinction as the result of human activity. An October 2020 IPBES report found the same human actions which drive biodiversity loss have also resulted in an increase in pandemics.

Biodiversity Hotspot

A biodiversity hotspot is a region with a high level of endemic species that have experienced great habitat loss. The term hotspot was introduced in 1988 by Norman Myers. While hotspots are spread all over the world, the majority are forest areas and most are located in the tropics.

Brazil's Atlantic Forest is considered one such hotspot, containing roughly 20,000 plant species, 1,350

vertebrates, and millions of insects, about half of which occur nowhere else. The island

of Madagascar and India are also particularly notable. Colombia is characterized by high biodiversity, with the highest rate of species by area unit worldwide and it has the largest number of endemics (species that are not found naturally anywhere else) of any country. About 10% of the species of the Earth can be found in Colombia, including over 1,900 species of bird, more than in Europe and North America combined, Colombia has 10% of the world's mammals species, 14% of the amphibian species, and 18% of the bird species of the world. Madagascar's dry deciduous forests and lowland rainforests possess a high ratio of endemism. Since the island separated from mainland Africa 66 million years ago, many species and ecosystems have evolved independently. Indonesia's 17,000 islands cover 735,355 square miles (1,904,560 km²) and contain 10% of the world's flowering plants, 12% of mammals, and 17% of reptiles, amphibians, and birds—along with nearly 240 million people. Many regions of high biodiversity and/or endemism arise from specialized habitats that require unusual adaptations, for example, alpine environments in high mountains, or Northern European peat bogs.

Ecosystem services

The balance of evidence

"Ecosystem services are the suite of benefits that ecosystems provide to humanity." The natural species, or biota, are the caretakers of all ecosystems. It is as if the natural world is an enormous bank account of capital assets capable of paying life-sustaining dividends indefinitely, but only if the capital is maintained.

These services come in three flavors:

1. Provisioning services which involve the production of renewable resources (e.g.: food, wood, freshwater)
2. Regulating services which are those that lessen environmental change (e.g.: climate regulation, pest/disease control)
3. Cultural services represent human value and enjoyment (e.g.: landscape aesthetics, cultural heritage, outdoor recreation, and spiritual significance)

Human health

Biodiversity's relevance to human health is becoming an international political issue, as scientific evidence

builds on the global health implications of biodiversity loss. This issue is closely linked with the issue of climate change, as many of the anticipated health risks of climate change are associated with changes in biodiversity (e.g. changes in populations and distribution of disease vectors, scarcity of freshwater, impacts on agricultural biodiversity, and food resources, etc.).

The growing demand and lack of drinkable water on the planet presents an additional challenge to the future of human health. Partly, the problem lies in the success of water suppliers to increase supplies and the failure of groups promoting the preservation of water resources. While the distribution of clean water increases, in some parts of the world it remains unequal. According to the World Health Organisation (2018), only 71% of the global population used a safely managed drinking-water service.

Some of the health issues influenced by biodiversity include dietary health and nutrition security, infectious disease, medical science and medicinal resources, social and psychological health. Biodiversity is also known to have an important role in reducing disaster risk and in post-disaster relief and recovery efforts.

According to the United Nations Environment Programme a pathogen, like a virus, have more chances to meet resistance in a diverse population. Therefore, in a population genetically similar it expands more easily. For example, the COVID-19 pandemic had fewer chances to occur in a world with higher biodiversity.

Species loss rates

During the last century, decreases in biodiversity have been increasingly observed. In 2007, Almost all

scientists acknowledge that the rate of species loss is greater now than at any time in human history, with extinctions occurring at rates hundreds of times higher than background extinction rates. As of 2012, some studies suggest that 25% of all mammal species could be extinct in 20 years.

In absolute terms, the planet has lost 58% of its biodiversity since 1970 according to a 2016 study by the World Wildlife FundThe Living Planet Report 2014 claims that "the number of mammals, birds, reptiles, amphibians, and fish across the globe is, on average, about half the size it was 40 years ago". Of that number, 39% accounts for the terrestrial wildlife gone, 39% for the marine wildlife gone, and 76% for the freshwater wildlife gone. Biodiversity took the biggest hit in Latin America, plummeting 83 percent. High-income countries showed a 10% increase in biodiversity, which was canceled out by a loss in low-income countries. This is despite the fact that high-income countries use five times the ecological resources of low-income countries, which was explained as a result of a process whereby wealthy nations are outsourcing resource depletion to poorer nations, which are suffering the greatest ecosystem losses.

In 2020 the World Wildlife Foundation published a report saying that "biodiversity is being destroyed at a rate unprecedented in human history". The report claims that 68% of the population of the examined species were destroyed in the years 1970 - 2016.

Threats

In 2006, many species were formally classified as rare or endangered, or threatened; moreover, scientists have estimated that millions more species are at risk which has not been formally recognized. About 40 percent of the 40,177 species assessed using the IUCN Red List criteria are now listed as threatened with extinction—a total of 16,119.

Habitat destruction

Habitat destruction has played a key role in extinctions, especially in relation to tropical forest destruction. Factors contributing to habitat loss include overconsumption, overpopulation, land-use change, deforestation, pollution (air pollution, water pollution, soil contamination), and global warming or climate change.

Habitat size and numbers of species are systematically related. Physically larger species and those living at lower latitudes or in forests or oceans are more sensitive to reduction in habitat area. Conversion to "trivial" standardized ecosystems (e.g., monoculture following deforestation) effectively destroys habitat for the more diverse species that preceded the conversion. Even the simplest forms of agriculture affect diversity – through clearing/draining the land, discouraging weeds and "pests", and encouraging just a limited set of domesticated plant and animal species. In some countries, property rights or lax law/regulatory enforcement are associated with deforestation and habitat loss.

Co-extinctions are a form of habitat destruction. Co-extinction occurs when the extinction or decline in one species accompanies similar processes in another, such as in plants and beetles.

A 2019 report has revealed that bees and other pollinating insects have been wiped out of almost a quarter of their habitats across the United Kingdom. The population crashes have been happening since the 1980s and are affecting biodiversity. The increase in industrial farming and pesticide use, combined with diseases, invasive species, and climate change is threatening the future of these insects and the agriculture they support.

In 2019, research was published showing that insects are destroyed by human activities like habitat destruction, pesticide poisoning, invasive species, and climate change at a rate that will cause the collapse of ecological systems in the next 50 years if it cannot be stopped.

Climate change

Global warming is a major threat to global biodiversity. For example, coral reefs – which are biodiversity hotspots – will be lost within the century if global warming continues at the current rate.

Climate change has proven to affect biodiversity and evidence supporting the altering effects is widespread. Increasing atmospheric carbon dioxide certainly affects plant morphology and is acidifying oceans, and temperature affects species ranges, phenology, and weather, but, mercifully, the major impacts that have been predicted are still potential futures. We have not documented major extinctions yet, even as climate change drastically alters the biology of many species.

A recent study predicts that up to 35% of the world's terrestrial carnivores and ungulates will be at higher risk of extinction by 2050 because of the joint effects of predicted climate and land-use change under business-as-usual human development scenarios.

Climate change has advanced the time of evening when Brazilian free-tailed bats (Tadarida brasiliensis)

emerge to feed. This change is believed to be related to the drying of regions as temperatures rise. This earlier emergence exposes the bats to greater predation increased competition with other insectivores who feed in the twilight or daylight hours.

Human overpopulation

The world's population numbered nearly 7.6 billion as of mid-2017 (which is approximately one billion more inhabitants compared to 2005) and is forecast to reach 11.1 billion in 2100. Sir David King, the former chief scientific adviser to the UK government, told a parliamentary inquiry: "It is self-evident that the massive

growth in the human population through the 20th century has had more impact on biodiversity than any other single factor." At least until the middle of the 21st century, worldwide losses of pristine biodiverse land will probably depend much on the worldwide human birth rate.

Some top scientists have argued that population size and growth, along with overconsumption, are significant factors in biodiversity loss and soil degradation. The 2019 IPBES Global Assessment Report on Biodiversity and Ecosystem Services and biologists including Paul R. Ehrlich and Stuart Pimm have noted that human population growth and overconsumption are the main drivers of species decline. E. O. Wilson, who contends that human population growth has been devastating to the planet's biodiversity, stated that the "pattern of human population growth in the 20th century was more bacterial than primate." He added that when Homo sapiens reached a population of six billion their biomass exceeded that of any other large land-dwelling animal species that had ever existed by over 100 times, and that "we and the rest of life cannot afford another 100 years like that".