Prediction of extinction in plants: interaction of extrinsic threats and life history traits.
The global extinction of species proceeds through the erosion of local populations. Using a 60-year time series of annual sighting records of plant species, we studied the correlates of local extinction risk associated with a risk of species extinction in the Park Grass Experiment where plants received long-term exposure to nutrient enrichment, soil acidification, and reductions in habitat size. We used multivariate linear models to assess how extrinsic threats and life history traits influence extinction risk. We investigated effects of four extrinsic threats (nitrogen enrichment, productivity, acidification, and plot size) as well as 11 life history traits (month of earliest flowering, flowering duration, stress tolerance, ruderalness [plant species' ability to cope with habitat disturbance], plant height, diaspore mass, seed bank, life form, dispersal mode, apomixis [the ability for a species to reproduce asexuall through seeds], and mating system). Extinction risk was not influenced by plant family. All of the 11 life history traits except life form and all threat variables influenced extinction risk but always via interactions which typically involved one threat variable and one life history trait. We detected comparatively few significant interactions between life history traits, and the interacting traits compensated for each other. These results suggest that simple predictions about extinction risk based on species' traits alone will often fail. In contrast, understanding the interactions between extrinsic threats and life history traits will allow us to make more accurate predictions of extinctions.
Fréville
Hélène
H
Ecology and Evolution Research Group, Department of Biological Sciences, Open University, Walton Hall, Milton Keynes, MK7 6AA, United Kingdom. freville@mnhn.fr
McConway
Kevin
K
Dodd
Mike
M
Silvertown
Jonathan
J
D000222:Adaptation, Physiological; D018533:Biomass; D003247:Conservation of Natural Resources; D017753:Ecosystem; D004777:Environment; D053476:Extinction, Biological; D006863:Hydrogen-Ion Concentration; D008954:Models, Biological; D015999:Multivariate Analysis; D009584:Nitrogen / Q000378:metabolism; D063245:Plant Development; D018521:Plant Physiological Phenomena; D006109:Poaceae / Q000254:growth & development / Q000502:physiology; D011156:Population Density; D011157:Population Dynamics; D011237:Predictive Value of Tests; D012307:Risk Factors; D012987:Soil / Q000032:analysis / Q000592:standards; D013045:Species Specificity
D012987:Soil; D009584:Nitrogen