title: Limited alpine climatic warming and modeled phenology advancement for three alpine species in the Northeast United States.
abstract: •
  
  
  OBJECTIVE
  Most alpine plants in the Northeast United States are perennial and flower early in the growing season, extending their limited growing season. Concurrently, they risk the loss of reproductive efforts to late frosts. Quantifying long-term trends in northeastern alpine flower phenology and late-spring/early-summer frost risk is limited by a dearth of phenology and climate data, except for Mount Washington, New Hampshire (1916 m a.s.l.).•
  
  
  METHODS
  Logistic phenology models for three northeastern US alpine species (Diapensia lapponica, Carex bigelowii and Vaccinium vitis-idaea) were developed from 4 yr (2008-2011) of phenology and air temperature measurements from 12 plots proximate to Mount Washington's long-term summit meteorological station. Plot-level air temperature, the logistic phenology models, and Mount Washington's climate data were used to hindcast model yearly (1935-2011) floral phenology and frost damage risk for the focal species.•
  
  
  RESULTS
  Day of year and air growing degree-days with threshold temperatures of -4°C (D. lapponica and C. bigelowii) and -2°C (V. vitis-idaea) best predicted flowering. Modeled historic flowering dates trended significantly earlier but the 77-yr change was small (1.2-2.1 d) and did not significantly increase early-flowering risk from late-spring/early-summer frost damage.•
  
  
  CONCLUSIONS
  Modeled trends in phenological advancement and sensitivity for three northeastern alpine species are less pronounced compared with lower elevations in the region, and this small shift in flower timing did not increase risk of frost damage. Potential reasons for limited earlier phenological advancement at higher elevations include a slower warming trend and increased cloud exposure with elevation and/or inadequate chilling requirements.
authors.affiliation: Research Department, Appalachian Mountain Club, 361 Route 16, Gorham, New Hampshire 03581 USA.
authors.forename: Kenneth D
authors.initials: KD
authors.lastname: Kimball
authors.affiliation: Research Department, Appalachian Mountain Club, 361 Route 16, Gorham, New Hampshire 03581 USA Ecology Center, Utah State University, 5205 Old Main Hill-NR 314, Logan, Utah 84322 USA.
authors.forename: Michael L
authors.initials: ML
authors.lastname: Davis
authors.affiliation: Research Department, Appalachian Mountain Club, 361 Route 16, Gorham, New Hampshire 03581 USA.
authors.forename: Douglas M
authors.initials: DM
authors.lastname: Weihrauch
authors.affiliation: Research Department, Appalachian Mountain Club, 361 Route 16, Gorham, New Hampshire 03581 USA.
authors.forename: Georgia L D
authors.initials: GL
authors.lastname: Murray
authors.affiliation: Mount Washington Observatory, 2779 White Mountain Highway, North Conway, New Hampshire 03860 USA.
authors.forename: Kenneth
authors.initials: K
authors.lastname: Rancourt
mesh_terms: D000531:Altitude; D031255:Carex Plant / Q000502:physiology; D002980:Climate; D017753:Ecosystem; D035264:Flowers / Q000254:growth & development*; D005615:Freezing; D057232:Global Warming; D019684:Magnoliopsida / Q000502:physiology*; D008954:Models, Biological; D009513:New Hampshire; D063245:Plant Development; D012098:Reproduction; D012621:Seasons; D013312:Stress, Physiological; D013696:Temperature; D029801:Vaccinium vitis-idaea / Q000502:physiology
keywords: Carex bigelowii; Diapensia lapponica; Mount Washington; New Hampshire; Vaccinium vitis-idaea; alpine plants; climate change; floral phenology; frost risk; long-term record