What Does Vulnerable Species Mean?
A vulnerable species is one that is not currently endangered but faces a high risk of endangerment in the near future, either due to a declining population or threats to natural habitats.
At present, 5,196 animal species and 6,789 plant species have been classified as vulnerable.
Safeopedia Explains Vulnerable Species
The disappearance of species reduces the planet's biodiversity, as well as the biodiversity of specific regions. This not only affects the species under threat but human beings as well. Since many plant and animal species are interdependent, the extinction of one can lead to the decline or extinction of other species we rely on for sustenance.
IUCN Red List Classifications
The International Union for Conservation of Nature (IUCN) Red List classifies species according to nine categories of IUCN:
- Not evaluated (NE)
- Data deficient (DD)
- Least concern (LC)
- Near threatened (NT)
- Vulnerable (VU)
- Endangered (EN)
- Critically endangered (CR)
- Extinct in the wild (EW)
- Extinct (EX)
The Red List further uses five threat categories, in descending order of severity:
- Extinct or extinct in the wild (no known living members of the species, or none outside of captivity)
- Critically endangered, endangered, or vulnerable (under threat of global extinction)
- Near threatened (close to the threatened thresholds, or would be threatened without ongoing conservation measures)
- Least concern (lower risk of extinction)
- Data deficient (insufficient information to determine threat category)
Factors Leading to Vulnerability and Extinction
Species populations undergo changes over time due to natural events or human intervention. A volcanic erruption can wipe out entire species of animals and plants within its vicinity. Extreme weather changes, floods, and droughts can disrupt natural habitats and threaten the survival of species that rely on them. Land development, pollution, overfishing, and the introduction of non-native species to an area can also endanger populations.
The IUCN defines a vulnerable (VU) as one that is "facing a high risk of extinction in the wild.” Their criteria for considering a species vulnerable includes:
- Population reduction of 50% or more over 10 years or three generations
- Livable habitat reduced to 20,000 km2 or less
- 10,000 or fewer adults in the species, with a 10% anticipated decline within 10 years or three generations
- Overall population size of 1,000 or fewer individuals
- Rapid decline, with quantitative analysis showing a 10% or greater probability of extinction within 100 years