title: Pushing the limit: experimental evidence of climate effects on plant range distributions.
abstract: Whether species will be extirpated in their current geographic ranges due to rapidly changing climate, and if so, whether they can avoid extinction by shifting their distributions are pressing questions for biodiversity conservation. However, forecasts of climate change impacts on species' geographic distributions rarely incorporate a demographic understanding of species' responses to climate. Because many biotic and abiotic factors at multiple scales control species' range limits, experimentation is essential to establish underlying mechanisms. We used a manipulative climate change experiment embedded within a natural climate gradient to examine demographic responses of 12 prairie species with northern range limits within the Pacific Northwest, USA. During the first year, warming decreased recruitment of species even at the coolest edge of their current ranges, but this effect disappeared when they were moved poleward beyond their current ranges. This response was largely driven by differences in germination rates. Other vital rates responded in unique and sometimes opposing ways (survivorship vs. fitness) to species' current ranges and climate change, and were mediated by indirect effects of climate on competition and nutrient availability. Our results demonstrate the importance of using regional-scale climate manipulations and the need for longer-term experiments on the demographic responses that control species' distributions.
authors.affiliation: Institute of Ecology and Evolution, University of Oregon, Eugene, Oregon 97403, USA. lpfeifermeister@gmail.com
authors.forename: Laurel
authors.initials: L
authors.lastname: Pfeifer-Meister
authors.affiliation: Institute of Ecology and Evolution, University of Oregon, Eugene, Oregon 97403, USA.
authors.forename: Scott D
authors.initials: SD
authors.lastname: Bridgham
authors.affiliation: Evolutionary Biology Center, Uppsala University, Uppsala 75236 Sweden.
authors.forename: Chelsea J
authors.initials: CJ
authors.lastname: Little
authors.affiliation: Institute of Ecology and Evolution, University of Oregon, Eugene, Oregon 97403, USA.
authors.forename: Lorien L
authors.initials: LL
authors.lastname: Reynolds
authors.affiliation: Institute of Ecology and Evolution, University of Oregon, Eugene, Oregon 97403, USA.
authors.forename: Maya E
authors.initials: ME
authors.lastname: Goklany
authors.affiliation: Environmental Science Institute, University of Oregon, Eugene, Oregon 97403, USA.
authors.forename: Bart R
authors.initials: BR
authors.lastname: Johnson
mesh_terms: D002980:Climate; D003710:Demography; D015205:Northwestern United States; D018521:Plant Physiological Phenomena; D010944:Plants / Q000145:classification*; D013045:Species Specificity