Threat of Extinction

According to the 2019 Global Assessment Report on Biodiversity and Ecosystem Services by the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services(IPBES), the biomass of wild mammals has fallen by 82%, natural ecosystems have lost about 50% of their area and a million species are at risk of extinction—all largely as a result of human actions. Twenty-five percent of plant and animal species are threatened with extinction. In a subsequent report, IPBES listed unsustainable fishing, hunting and logging as being some of the primary drivers of the global extinction crisis.

In June 2019, one million species of plants and animals were at risk of extinction. At least 571 species have been lost since 1750, but likely many more. The main cause of the extinctions is the destruction of natural habitats by human activities, such as cutting down forests and converting land into fields for farming.

According to a 1998 survey of 400 biologists conducted by New York’s American Museum of Natural History, nearly 70% believed that the Earth is currently in the early stages of a human-caused mass extinction,

The following information was presented by David Attenborough in 2023:

Extinctions are happening simultaneously across the planet. Previously extinction-evolution occurred over millions of years. Now extinction progresses in 10s of years. Currently 25% of plant species are at risk.

The following is a list of some of the causes threats to species and extinction

• habitat loss – to logging, farming and mining
• pressure on resources, due to population growth, increased consumption of resources
• the hunting and harvesting of species to extinction
• invasive species displacing endemic (native) species
• invasive diseases— for example, bats are killed by white nose syndrome
• invasive insects such as the spruce bud worm (Choristoneura freemani) and mountain pine beetle (Dendroctonus ponderosae)
• replacement (replanting) of endemic species with monocultures (seeds and seedlings from a restricted genome)
• changes driven by climate, global warming, some species that can not tolerate warming temperatures, others are affected by insect swarms
• microplastics in water
• contamination from manufacturing and refining
• use of poisons ( for example DDT and PCBs)
• loss of carbon sinks
• lack of diversity of soil microbes due to industrial farming and reliance on chemical fertilizers
• genetic pollution—i.e., uncontrolled hybridization
• co-extinction—the loss of one species leading to the loss of other, dependent species. (loss of species dependent on another threatened or extinct species)
• loss of pollinators

One species can become threatened by a number of factors. For example, Pacific salmon are in decline due to warming water, fish farms, land-slides blocking rivers, over fishing, destruction of rearing areas, and logging—all leading to destruction of spawning grounds. The decline of salmon has impact on other species such as killer whales.

Research and data on species at risk in British Columbia can be obtained from the following page of the British Columbia Conservation Data Centre and by conducting searches in the BC Species and Ecosystems Explorer.

Invasion of ecosystems, in the wild, by humans leads to another threat to humanity, the transmission of diseases from wild animals to people. Ebola, likely originally transmitted to humans by African fruit bats, kills 25-90% percent of people infected.