title: Forest succession and population viability of grassland plants: long repayment of extinction debt in Primula veris.
abstract: Time lags in responses of organisms to deteriorating environmental conditions delay population declines and extinctions. We examined how local processes at the population level contribute to extinction debt, and how cycles of habitat deterioration and recovery may delay extinction. We carried out a demographic analysis of the fate of the grassland perennial Primula veris after the cessation of grassland management, where we used either a unidirectional succession model for forest habitat or a rotation model with a period of forest growth followed by a clear-cut and a new successional cycle. The simulations indicated that P. veris populations may have an extinction time of decades to centuries after a detrimental management change. A survey of the current incidence and abundance of P. veris in sites with different histories of afforestation confirmed the simulation results of low extinction rates. P. veris had reduced incidence and abundance only at sites with at least 100 years of forest cover. Time to extinction in simulations was dependent on the duration of the periods with favourable and unfavourable conditions after management cessation, and the population sizes and growth rates in these periods. Our results thus suggest that the ability of a species to survive is a complex function of disturbance regimes, rates of successional change, and the demographic response to environmental changes. Detailed demographic studies over entire successional cycles are therefore essential to identify the environmental conditions that enable long-term persistence and to design management for species experiencing extinction debts.
authors: School of Natural Sciences, Technology and Environmental Studies, Södertörn University, SE-14189, Huddinge, Sweden. kari.lehtila@sh.se.
authors: Kari
authors: K
authors: Lehtilä
authors: Department of Biology and Max-Planck Odense Center of the Biodemography of Aging, University of Southern Denmark, Campusvej 55, 5230, Odense M, Denmark.
authors: Johan P
authors: JP
authors: Dahlgren
authors: Instituto Pirenaico de Ecología (CSIC), Apdo. 13034, 50080, Saragossa, Spain.
authors: Maria Begoña
authors: MB
authors: Garcia
authors: Department of Plant Sciences, University of Oxford, South Parks Road, Oxford, OX1 3RB, UK.
authors: Roosa
authors: R
authors: Leimu
authors: Finnish Environment Institute, FI-00251, Helsinki, Finland.
authors: Kimmo
authors: K
authors: Syrjänen
authors: Department of Ecology, Environment and Plant Sciences, Stockholm University, Lilla Frescati, SE-106 91, Stockholm, Sweden.
authors: Johan
authors: J
authors: Ehrlén
mesh_terms: D005387:Finland; D065928:Forests; D065948:Grassland; D008954:Models, Biological; D011157:Population Dynamics; D031825:Primula / Q000502:physiology*; D013548:Sweden
keywords: Conservation; Demography; Habitat closure; Persistence; Population dynamics