Sammanfattning

Demographic stochasticity is important in determining extinction risks of small populations, but it is largely unknown how its effect depends on the life histories of species. We modeled effects of demographic stochasticity on extinction risk in a broad range of generalized life histories, using matrix models and branching processes. Extinction risks of life histories varied greatly in their sensitivity to demographic stochasticity. Comparing life histories, extinction risk generally increased with increasing fecundity and decreased with higher ages of maturation. Effects of adult survival depended on age of maturation. At lower ages of maturation, extinction risk peaked at intermediate levels of adult survival, but it increased along with adult survival at higher ages of maturation. These differences were largely explained by differences in sensitivities of population growth to perturbations of life history traits. Juvenile survival rate contributed most to total demographic variance in the majority of life histories. Our general results confirmed earlier findings, suggesting that empirical patterns can be explained by a relatively simple model. Thus, basic life history information can be used to assign life history-specific sensitivity to demographic stochasticity. This is of great value when assessing the vulnerability of small populations.

Nyckelord

Extinction risk; Demographic stochasticity; matrix model; branching process; demographic variance; population dynamics; life history

Publicerad i

American Naturalist
2012, Volym: 179, nummer: 6, sidor: 706-720

SLU författare

• Jeppsson, Tobias

  • Institutionen för ekologi, Sveriges lantbruksuniversitet
    

• Forslund, Pär

  • Institutionen för ekologi, Sveriges lantbruksuniversitet
    

Globala målen

Skydda, återställa och främja ett hållbart nyttjande av landbaserade ekosystem, hållbart bruka skogar, bekämpa ökenspridning, hejda och vrida tillbaka markförstöringen samt hejda förlusten av biologisk mångfald


UKÄ forskningsämne

Ekologi


Publikationens identifierare

DOI: https://doi.org/10.1086/665696

Permanent länk till denna sida (URI)

https://res.slu.se/id/publ/38909