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In ecology, rarefaction is a technique to assess species richness from the results of sampling. Rarefaction allows the calculation of species richness for a given number of individual samples, based on the construction of so-called rarefaction curves. This curve is a plot of the number of species as a function of the number of samples.
Freshwater species are beginning to decline at twice the rate of species that live on land or in the ocean. This rapid loss has already placed 27% of 29,500 species dependent on fresh water on the IUCN Red List. [100] Global populations of freshwater fish are collapsing due to water pollution and overfishing. Migratory fish populations have ...
As at July 2018, the OBIS website states that the system provides access to over 45 million observations of nearly 120,000 marine species (the reduced number of names cited being as a result of synonym resolution, i.e. reduction of taxa recorded under multiple names to a single accepted name), based on contributions from 500 institutions from ...
The Red List Index (sampled approach) (SRLI) has been developed in order to determine the threat status and also trends of lesser-known and less charismatic species groups. It is a collaboration between IUCN members and is coordinated through the Institute of Zoology (IoZ), the research division of the Zoological Society of London (ZSL).
The World Wildlife Fund’s Living Planet Report 2022 found that wildlife populations declined by an average 69% since 1970. [1] [2] [3]The Living Planet Index (LPI) is an indicator of the state of global biological diversity, based on trends in vertebrate populations of species from around the world.
These papers utilized the compendium to track origination rates (the rate that new species appear or speciate) parallel to extinction rates in the context of geological stages or substages. [60] A review and re-analysis of Sepkoski's data by Bambach (2006) identified 18 distinct mass extinction intervals, including 4 large extinctions in the ...
The rank abundance curve visually depicts both species richness and species evenness. Species richness can be viewed as the number of different species on the chart i.e., how many species were ranked. Species evenness is reflected in the slope of the line that fits the graph (assuming a linear, i.e. logarithmic series, relationship).
In conservation biology, latent extinction risk is a measure of the potential for a species to become threatened.. Latent risk can most easily be described as the difference, or discrepancy, between the current observed extinction risk of a species (typically as quantified by the IUCN Red List) and the theoretical extinction risk of a species predicted by its biological or life history ...