Animals and plants facing extinction share these characteristics

By Mark Waghorn via SWNS

Animals and plants facing extinction share common characteristics, according to new research.

Birds, for instance, are more vulnerable with high progressive growth and reproduction rates.

Mammals, on the other hand, are more prone when they have longer generation times.

The findings are based on an analysis of 159 different organisms. They could help save threatened species.

Lead author Haydee Hernandez-Yanez, of Woodwell Climate Research Centre, Massachusetts, said: "These patterns may be used to assess relative vulnerability across species when lacking abundance or trend data."

The idea of determining ahead of time which can be wiped out is vital in conservation biology.

Susceptibility is dependent upon both life-history strategies and genetics and environmental and manmade threats.

Ms. Hernandez-Yanez, a research assistant, said: "Studies linking intrinsic traits to extinction risk have shown variable results.

"To our knowledge, there has not been a systematic analysis looking at how demographic patterns in stage-specific survival and reproductive rates correlate to extinction risk."

The US team carried out the investigation by using computer prediction models and IUCN Red List status of herbaceous plants, trees, mammals and birds.

They calculated 14 demographic metrics and mapped all species within the database, both with IUCN assessment and without - then overlaid them with biodiversity hotspots.

Ms. Hernandez-Yanez said: "We found herbaceous perennials are more vulnerable when they mature early and have high juvenile survival rates.

"Birds are more vulnerable with high progressive growth and reproduction and mammals when they have longer generation times."

Climate change, habitat loss, pollution and poaching has led to record loss of biodiversity and the acceleration of species extinction rates unprecedented in human history.

The predictions would help conservationists identify which species are most prone to extinction - and others that could be en route.

Ms. Hernandez-Yanez said: "Despite our relatively small sample of species, we found that species with certain demographic patterns are more at risk of extinction than others, and that the important predictors differed between taxonomic groups.

"These findings show that, indeed, taxa can differ in the most important variables that explain their vulnerability to extinction, and also that human disturbance (the main extrinsic cause of extinction) does not affect all species equally due to their intrinsic biology."

The results are consistent with earlier studies that showed shorter lifespans correlate with higher extinction risk in plants.

Species with shorter lifespans, such as biennial plants (flowering plants that take two years to complete their biological life cycle) have lower adult survival rates and a 'fast' life history strategy.

This can be associated with earlier maturation and higher survival in the pre-reproductive stages.

In the case of birds, the results correspond with predictions from simulation studies, which found that species with early maturation are more vulnerable when they have higher reproduction and intermediate adult survival, or when they have many small offspring.

In mammals, earlier findings also show that slow life histories are associated with a high extinction risk broadly and in carnivores and primates.

Ms. Hernandez-Yanez added: "Future analyses could also use the geolocations to compile information on extrinsic factors such as human population density and level of urban development to examine the relative importance of extrinsic versus intrinsic factors on vulnerability to extinction."

The study was published in PLoS ONE.