Fires slow population declines of a long-lived prairie plant through multiple vital rates.

Autor: Nordstrom SW; Negaunee Institute for Plant Conservation Science and Action, Chicago Botanic Garden, 1000 Lake Cook Rd, Glencoe, IL, 60022, USA. scottwatsonnordstrom@gmail.com.; BioFrontiers Institute, University of Colorado Boulder, 3145 Colorado Avenue, Boulder, CO, 80303, USA. scottwatsonnordstrom@gmail.com.; Department of Ecology and Evolutionary Biology, University of Colorado Boulder, 1900 Pleasant Street, 334 UCB, Boulder, CO, 80309, USA. scottwatsonnordstrom@gmail.com., Dykstra AB; Department of Biological Sciences, Bethel University, 3900 Bethel Drive, St. Paul, MN, 55112, USA., Wagenius S; Negaunee Institute for Plant Conservation Science and Action, Chicago Botanic Garden, 1000 Lake Cook Rd, Glencoe, IL, 60022, USA.
Jazyk: angličtina
Zdroj: Oecologia [Oecologia] 2021 Jul; Vol. 196 (3), pp. 679-691. Date of Electronic Publication: 2021 Jun 02.
DOI: 10.1007/s00442-021-04955-2
Abstrakt: In grasslands worldwide, modified fire cycles are accelerating herbaceous species extinctions. Fire may avert population declines by increasing survival, reproduction, or both. Survival and growth after fires may be promoted by removal of competitors or biomass and increasing resource availability. Fire-stimulated reproduction may also contribute to population growth through bolstered recruitment. We quantified these influences of fire on population dynamics in Echinacea angustifolia, a perennial forb in North American tallgrass prairie. We first used four datasets, 7-21 years long, to estimate fire's influences on survival, flowering, and recruitment. We then used matrix projection models to estimate growth rates across several burn frequencies in five populations, each with one to four burns over 15 years. Finally, we estimated the contribution of fire-induced changes in each vital rate to changes in population growth. Population growth rates generally increased with burning. The demographic process underpinning these increases depended on juvenile survival. In populations with high juvenile survival, fire-induced increases in seedling recruitment and juvenile survival enhanced population growth. However, in populations with low juvenile survival, small changes in adult survival drove growth rate changes. Regardless of burn frequencies, our models suggest populations are declining and that recruitment and juvenile survival critically influence population response to fire. However, crucially, increased seedling recruitment only increases population growth rates when enough new recruits reach reproductive maturity. The importance of recruitment and juvenile survival is especially relevant for small populations in fragmented habitats subject to mate-limiting Allee effects and inbreeding depression, which reduce recruitment and survival, respectively.
(© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)
Databáze: MEDLINE
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