TY - JOUR
T1 - Lab and field warming similarly advance germination date and limit germination rate for high and low elevation provenances of two widespread subalpine conifers
AU - Kueppers, Lara M.
AU - Faist, Akasha
AU - Ferrenberg, Scott
AU - Castanha, Cristina
AU - Conlisk, Erin
AU - Wolf, Jennifer
N1 - Publisher Copyright:
© 2017 by the authors.
PY - 2017/11/11
Y1 - 2017/11/11
N2 - Accurately predicting upslope shifts in subalpine tree ranges with warming requires understanding how future forest populations will be affected by climate change, as these are the seed sources for new tree line and alpine populations. Early life history stages are particularly sensitive to climate and are also influenced by genetic variation among populations. We tested the climate sensitivity of germination and initial development for two widely distributed subalpine conifers, using controlled-environment growth chambers with one temperature regime from subalpine forest in the Colorado Rocky Mountains and one 5 °C warmer, and two soil moisture levels. We tracked germination rate and timing, rate of seedling development, and seedling morphology for two seed provenances separated by ~300 m elevation. Warming advanced germination timing and initial seedling development by a total of ~2 weeks, advances comparable to mean differences between provenances. Advances were similar for both provenances and species; however, warming reduced the overall germination rate, as did low soil moisture, only for Picea engelmannii. A three-year field warming and watering experiment planted with the same species and provenances yielded responses qualitatively consistent with the lab trials. Together these experiments indicate that in a warmer, drier climate, P. engelmannii germination, and thus regeneration, could decline, which could lead to declining subalpine forest populations, while Pinus flexilis forest populations could remain robust as a seed source for upslope range shifts.
AB - Accurately predicting upslope shifts in subalpine tree ranges with warming requires understanding how future forest populations will be affected by climate change, as these are the seed sources for new tree line and alpine populations. Early life history stages are particularly sensitive to climate and are also influenced by genetic variation among populations. We tested the climate sensitivity of germination and initial development for two widely distributed subalpine conifers, using controlled-environment growth chambers with one temperature regime from subalpine forest in the Colorado Rocky Mountains and one 5 °C warmer, and two soil moisture levels. We tracked germination rate and timing, rate of seedling development, and seedling morphology for two seed provenances separated by ~300 m elevation. Warming advanced germination timing and initial seedling development by a total of ~2 weeks, advances comparable to mean differences between provenances. Advances were similar for both provenances and species; however, warming reduced the overall germination rate, as did low soil moisture, only for Picea engelmannii. A three-year field warming and watering experiment planted with the same species and provenances yielded responses qualitatively consistent with the lab trials. Together these experiments indicate that in a warmer, drier climate, P. engelmannii germination, and thus regeneration, could decline, which could lead to declining subalpine forest populations, while Pinus flexilis forest populations could remain robust as a seed source for upslope range shifts.
KW - Climate change experiment
KW - Niwot Ridge
KW - Picea engelmannii
KW - Pinus flexilis
KW - Seed germination
KW - Seedling development
UR - http://www.scopus.com/inward/record.url?scp=85033723877&partnerID=8YFLogxK
U2 - 10.3390/f8110433
DO - 10.3390/f8110433
M3 - Article
AN - SCOPUS:85033723877
SN - 1999-4907
VL - 8
JO - Forests
JF - Forests
IS - 11
M1 - 433
ER -