Human impact on nature Plan: Human impact on nature

Decline in biodiversity[edit]
See also: Decline in amphibian populations
Summary of major biodiversity-related environmental-change categories expressed as a percentage of human-driven change (in red) relative to baseline (blue)
Defaunation is the loss of animals from ecological communities.^[129]
It has been estimated that from 1970 to 2016, 68% of the world's wildlife has been destroyed due to human activity.^[130][131] In South America, there is believed to be a 70 percent loss.^[132] A May 2018 study published in PNAS found that 83% of wild mammals, 80% of marine mammals, 50% of plants and 15% of fish have been lost since the dawn of human civilization. Currently, livestock make up 60% of the biomass of all mammals on earth, followed by humans (36%) and wild mammals (4%).^[29] According to the 2019 global biodiversity assessment by IPBES, human civilization has pushed one million species of plants and animals to the brink of extinction, with many of these projected to vanish over the next few decades.^{[101][133][134]}
When plant biodiversity declines, the remaining plants face diminishing productivity.^[135] Biodiversity loss threatens ecosystem productivity and services such as food, fresh water, raw materials and medicinal resources.^[135]
A 2019 report that assessed a total of 28,000 plant species concluded that close to half of them were facing a threat of extinction. The failure of noticing and appreciating plants is regarded as "plant blindness", and this is a worrying trend as it puts more plants at the threat of extinction than animals. Our increased farming has come at a higher cost to plant biodiversity as half of the habitable land on Earth is used for agriculture, and this is one of the major reasons behind the plant extinction crisis.^[136]
Invasive species[edit]
Main article: Invasive species
Invasive species are defined by the U.S. Department of Agriculture as non-native to the specific ecosystem, and whose presence is likely to harm the health of humans or the animals in said system.^[137]
Introductions of non-native species into new areas have brought about major and permanent changes to the environment over large areas. Examples include the introduction of Caulerpa taxifolia into the Mediterranean, the introduction of oat species into the California grasslands, and the introduction of privet, kudzu, and purple loosestrife to North America. Rats, cats, and goats have radically altered biodiversity in many islands. Additionally, introductions have resulted in genetic changes to native fauna where interbreeding has taken place, as with buffalo with domestic cattle, and wolves with domestic dogs.