The Holocene extinction, or Anthropocene extinction, is the ongoing extinction event caused by humans damaging the environment (ecocide) during the Holocene epoch. These extinctions span numerous families of plants and animals, including mammals, birds, reptiles, amphibians, fish, and invertebrates, and affecting not just terrestrial species but also large sectors of marine life. With widespread degradation of biodiversity hotspots, such as coral reefs and rainforests, as well as other areas, the vast majority of these extinctions are thought to be undocumented, as the species are undiscovered at the time of their extinction, which goes unrecorded. The current rate of extinction of species is estimated at 100 to 1,000 times higher than natural background extinction rates and is increasing.
Biodiversity or biological diversity is the variety and variability of life on Earth. Biodiversity is a measure of variation at the genetic, species, and ecosystem level. Biodiversity is not distributed evenly on Earth; it is usually greater in the tropics as a result of the warm climate and high primary productivity in the region near the equator. Tropical forest ecosystems cover less than 10% of earth's surface and contain about 90% 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.
Extinction is the termination of a taxon by the death of its last member. A taxon may become functionally extinct before the death of its last member if it loses the capacity to reproduce and recover. Because a species' potential range may be very large, determining this moment is difficult, and is usually done retrospectively. This difficulty leads to phenomena such as Lazarus taxa, where a species presumed extinct abruptly "reappears" after a period of apparent absence.
Conservation biology is the study of the conservation of nature and of Earth's biodiversity with the aim of protecting species, their habitats, and ecosystems from excessive rates of extinction and the erosion of biotic interactions. It is an interdisciplinary subject drawing on natural and social sciences, and the practice of natural resource management.
Habitat conservation is a management practice that seeks to conserve, protect and restore habitats and prevent species extinction, fragmentation or reduction in range. It is a priority of many groups that cannot be easily characterized in terms of any one ideology.
The Anthropocene is a proposed geological epoch dating from the commencement of significant human impact on Earth's geology and ecosystems, including, but not limited to, human-caused climate change. The nature of the effects of humans on Earth can be seen for example in biodiversity loss, climate change, biogeography and nocturnality parameters, changes in geomorphology and stratigraphy.
An ecological or environmental crises occurs when changes to the environment of a species or population destabilizes its continued survival. Some of the important causes include:
There are several plausible pathways that could lead to an increased extinction risk from climate change. This is because every plant and animal species has evolved to exist within a certain ecological niche, and as climate change represents the long-term alteration of temperature and average weather patterns, it can push climatic conditions outside of the species' niche, which will ultimately render it extinct. Normally, species faced with changing conditions can either adapt in place through microevolution or move to another habitat with suitable conditions. However, the speed of recent climate change is so unprecedented, that even under "mid-range" scenarios of future warming, only 5% of current ectotherm locations are within 50 km of a place which could serve as an equally suitable habitat at the end of this century.
Bird extinction is the complete elimination of all species members under the taxonomic class, Aves. Out of all known bird species,, 159 (1.4%) have become extinct, with 226 (2%) being critically endangered. There is a general consensus among ornithologists that if anthropogenic activities continue as current trends suggest, one-third of all bird species, and an even greater proportion of bird populations, will be rendered extinct by the end of the 21st century.
Lee Hannah is a conservation ecologist and a Senior Researcher in Climate Change Biology at Conservation International. Hannah is one of many authors who published an article predicting that between 15% and 37% of species are at risk of extinction due to climate change caused by human greenhouse gas emissions.
Global biodiversity is the measure of biodiversity on planet Earth and is defined as the total variability of life forms. More than 99 percent of all species that ever lived on Earth are estimated to be extinct. Estimates on the number of Earth's current species range from 2 million to 1 trillion, but most estimates are around 11 million species or fewer. About 1.74 million species were databased as of 2018, and over 80 percent have not yet been described. The total amount of DNA base pairs on Earth, as a possible approximation of global biodiversity, is estimated at 5.0 x 1037, and weighs 50 billion tonnes. In comparison, the total mass of the biosphere has been estimated to be as much as 4 TtC (trillion tons of carbon).
Defaunation is the global, local, or functional extinction of animal populations or species from ecological communities. The growth of the human population, combined with advances in harvesting technologies, has led to more intense and efficient exploitation of the environment. This has resulted in the depletion of large vertebrates from ecological communities, creating what has been termed "empty forest". Defaunation differs from extinction; it includes both the disappearance of species and declines in abundance. Defaunation effects were first implied at the Symposium of Plant-Animal Interactions at the University of Campinas, Brazil in 1988 in the context of Neotropical forests. Since then, the term has gained broader usage in conservation biology as a global phenomenon.
In ecology, extinction debt is the future extinction of species due to events in the past. The phrases dead clade walking and survival without recovery express the same idea.
William F. Laurance, also known as Bill Laurance, is Distinguished Research Professor at James Cook University, Australia and has been elected as a Fellow of the Australian Academy of Science. He has received an Australian Laureate Fellowship from the Australian Research Council. He held the Prince Bernhard Chair for International Nature Conservation at Utrecht University, Netherlands from 2010 to 2014.
Katherine Elizabeth Jones is a British biodiversity scientist, with a special interest in bats. She is Professor of Ecology and Biodiversity, and Director of the Biodiversity Modelling Research Group, at University College London. She is a past chair of the Bat Conservation Trust.
Biodiversity loss includes the worldwide extinction of different species, as well as the local reduction or loss of species in a certain habitat, resulting in a loss of biological diversity. The latter phenomenon can be temporary or permanent, depending on whether the environmental degradation that leads to the loss is reversible through ecological restoration/ecological resilience or effectively permanent. The current global extinction, has resulted in a biodiversity crisis being driven by human activities which push beyond the planetary boundaries and so far has proven irreversible.
Lian Pin Koh is a Singaporean conservation scientist. He is the Kwan Im Thong Hood Cho Temple Professor of Conservation, Vice Dean of Research at the Faculty of Science, Director of the Centre for Nature-based Climate Solutions, and Director of the Tropical Marine Science Institute at the National University of Singapore (NUS).
Erika S. Zavaleta is an American professor of ecology and evolutionary biology at the University of California, Santa Cruz. Zavaleta is recognized for her research focusing on topics including plant community ecology, conservation practices for terrestrial ecosystems, and impacts of community dynamics on ecosystem functions.
Insects are the most numerous and widespread class in the animal kingdom, accounting for up to 90% of all animal species. In the 2010s, multiple reports about the widespread decline in insect populations across multiple orders have emerged. The reported severity had shocked many observers, even though it was preceded by the earlier findings of pollinator decline, as well as anecdotal evidence of greater apparent abundance of insects earlier in the 20th century, such as the windscreen phenomenon. Possible causes are similar to those causing other biodiversity loss, namely habitat destruction, including intensive agriculture; the use of pesticides ; urbanization, and industrialization; introduced species; and - to a lesser degree and only for some regions - climate change.
Shahid Naeem is an ecologist and conservation biologist and is a Lenfest Distinguished professor and chair in the Department of Ecology, Evolution, and Environmental Biology at Columbia University. Naeem is the author of Biodiversity, Ecosystem Functioning, and Human Well-Being, and has published over 100 scientific articles.
