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Many of the causes of amphibian declines are well understood, and appear to affect other groups of organisms as well as amphibians. These causes include habitat modification and fragmentation, introduced predators or competitors, introduced species, pollution, pesticide use, or over-harvesting. However, many amphibian declines or extinctions ...
The decrease can be temporary or permanent. It is temporary if the damage that led to the loss is reversible in time, for example through ecological restoration. If this is not possible, then the decrease is permanent. The cause of most of the biodiversity loss is, generally speaking, human activities that push the planetary boundaries too far.
[27]: 2321 For example, the decline of sea ice in the Arctic has been accelerating during the early twenty‐first century, with a decline rate of 4.7% per decade (it has declined over 50% since the first satellite records). [28] [29] [30] One well known example of a species affected is the polar bear, whose habitat in the Arctic is threatened ...
If oxygen depletion progresses to hypoxia, fish kills can occur and invertebrates like worms and clams on the bottom may be killed as well. Still frame from an underwater video of the sea floor. The floor is covered with crabs, fish, and clams apparently dead or dying from oxygen depletion. Hypoxia may also occur in the absence of pollutants.
As per the Millennium Ecosystem Assessment of 2005, land degradation is in defined as "the reduction or loss of the biological or economic productivity of drylands". [5] A similar definition states that land degradation is the "degradation, impoverishment and long-term loss of ecosystem services".
Desertification is a gradual process of increased soil aridity.Desertification has been defined in the text of the United Nations Convention to Combat Desertification (UNCCD) as "land degradation in arid, semi-arid and dry sub-humid regions resulting from various factors, including climatic variations and human activities."
The release of nitrogen oxides (N 2 O, NO) from anthropogenic activities and oxygen-depleted zones causes stratospheric ozone depletion leading to higher UVB exposition, which produces the damage of marine life, acid rain and ocean warming. Ocean warming causes water stratification, deoxygenation, and the formation of dead zones.
An extinction event (also known as a mass extinction or biotic crisis) is a widespread and rapid decrease in the biodiversity on Earth.Such an event is identified by a sharp fall in the diversity and abundance of multicellular organisms.