title: Plant communities on infertile soils are less sensitive to climate change.
abstract: OBJECTIVE
  Much evidence suggests that plant communities on infertile soils are relatively insensitive to increased water deficit caused by increasing temperature and/or decreasing precipitation. However, a multi-decadal study of community change in the western USA does not support this conclusion. This paper tests explanations related to macroclimatic differences, overstorey effects on microclimate, variation in soil texture and plant functional traits.
  
  
  METHODS
  A re-analysis was undertaken of the changes in the multi-decadal study, which concerned forest understorey communities on infertile (serpentine) and fertile soils in an aridifying climate (southern Oregan) from 1949-1951 to 2007-2008. Macroclimatic variables, overstorey cover and soil texture were used as new covariates. As an alternative measure of climate-related change, the community mean value of specific leaf area was used, a functional trait measuring drought tolerance. We investigated whether these revised analyses supported the prediction of lesser sensitivity to climate change in understorey communities on infertile serpentine soils.
  
  
  RESULTS
  Overstorey cover, but not macroclimate or soil texture, was a significant covariate of community change over time. It strongly buffered understorey temperatures, was correlated with less change and averaged >50 % lower on serpentine soils, thereby counteracting the lower climate sensitivity of understorey herbs on these soils. Community mean specific leaf area showed the predicted pattern of less change over time in serpentine than non-serpentine communities.
  
  
  CONCLUSIONS
  Based on the current balance of evidence, plant communities on infertile serpentine soils are less sensitive to changes in the climatic water balance than communities on more fertile soils. However, this advantage may in some cases be lessened by their sparser overstorey cover.
authors.affiliation: Department of Environmental Science and Policy, University of California-Davis, Davis, CA 95616, USA, spharrison@ucdavis.edu.
authors.forename: Susan
authors.initials: S
authors.lastname: Harrison
authors.affiliation: Department of Zoology, University of Wisconsin-Madison, Madison, WI 53706, USA.
authors.forename: Ellen
authors.initials: E
authors.lastname: Damschen
authors.affiliation: Wildland Resources Department, Utah State University, 5230 Old Main Hill, Logan, UT 84322-5230, USA and.
authors.forename: Barbara
authors.initials: B
authors.lastname: Fernandez-Going
authors.affiliation: Department of Biology, University of Oulu, PO Box 3000, FI-90014 University of Oulu, Finland.
authors.forename: Anu
authors.initials: A
authors.lastname: Eskelinen
authors.affiliation: Department of Environmental Science and Policy, University of California-Davis, Davis, CA 95616, USA.
authors.forename: Stella
authors.initials: S
authors.lastname: Copeland
mesh_terms: D057231:Climate Change; D017753:Ecosystem; D065928:Forests; D018521:Plant Physiological Phenomena; D010944:Plants; D012987:Soil / Q000737:chemistry*; D013312:Stress, Physiological; D013696:Temperature; D014867:Water / Q000502:physiology
chemical_list: D012987:Soil; D014867:Water
keywords: Klamath–Siskiyou; Plant community change; biogeographical affinity; climate change; climate resilience; climate resistance; plant functional traits; serpentine soil; soil fertility; specific leaf area; stress tolerance; topographic affinity