24th Congress for Conservation Biology, Canada 2010
1
Figure 1: Long-term trend (1901–1997) in first-flowering dates of Aspen in Alberta (adapted from Beaubien and Freeland (2000). Divergence of Community Bloom Patterns In a controlled warming experiment, Sherry et al. (2007) report that early-flowering grass and herb species flowered earlier, while late- summer flowering species flowered later than in the control (Figure 2). Simulated warming therefore significantly affected the temporal overlap of reproductive stages between successively blooming species. Figure 1: Divergence in flowering date of 12 herbaceous and graminoid species (Sherry et al, 2007). Phenological consequences of climate change. • The earth’s average surface temperature may increase by 1.4 to 5.8°C between 1990 and 2100, with greater increases in northern latitudes (IPCC 2007). • Average spring temperatures in Canada increased by 1.4 °C between 1948 and 1999 with greater warming in winter / spring . • Projected temperature increases of 2 to >10 °C for Canada by 2100, depending on model scenario (Lemmen et al, 2008) (example in Figure 3). • Potential for reduced snow cover, late-winter warming, thaw- freeze events, extended growing season, increased evapotranspiration, altered precipitation patterns. Figure 3. Projected temperature changes under scenario IS92a of the Canadian Climate Model (Environment Canada, date?) Phenological consequences of these changes may include: • Earlier and/or abnormal leaf unfolding in the event of failure to complete chilling requirements (Morin et al. 2009) • Seasonality: Shifts in flowering and seed set to both earlier and later than long-run averages could occur (Figure 2). • Longer growing seasons, which may translate into increased primary production. Productivity is also contingent, however, on concurrent changes in precipitation, seasonality and CO 2 concentrations. • Frost damage: Earlier bud break and later senescence may expose plants to damaging frosts in the spring, and incomplete resorption of foliar N in the autumn (Norby et al., 2003). Frost damage may also reduce seed production, which may have demographic consequences. • Range extensions or contractions may occur. Range extension may be facilitated by extension of favourable climate out of current range. Range contraction over time if climate shifts beyond adaptive envelope of key phenophases (e.g. seed germination). Factors Influencing Plant Phenology The timing of phenophases is thought to be under strong genetic control, leading to regionally adapted ecotypes that are influenced by: Temperature: Leaf unfolding and budburst respond strongly to temperature. Frost: If late season frosts occur after budburst or flowering, reproductive failure and reduced growth of the tree in that season can occur (ref). Chilling: Full winter dormancy may require periods of chilling that includes super-cooling and dessication of cell protoplasm. Photoperiod: Photoperiod initiates dormancy adaptation in latitudinally adapted tree ecotypes. Evapotranspiration: increased surface temperature and likely reduced summer precipitation Drought: Seasonal drought during the growing season which lead to reduce the growth of the tree. What is Phenology? Phenology is defined as the study of the timing of recurring biological phases of an organism, including the biotic and abiotic causes of this timing, and the interrelationships of phenophases among species (Lieth, 1974). Phenology is a dominant, often overlooked aspect of plant ecology, from the scale of individuals to whole ecosystems (Cleland et al. 2008). Important phenological events for plants include: • Bud burst and Leaf unfolding, • Flowering and setting fruit • Autumn or dry season leaf drop, and • The related processes of winter hardening and breaking dormancy. Selected References Abu-Asab, M., Peterson, S., Stanwyn, P.M., Shelter, G. and Sylvia, S., (2001) Earlier plant flowering in spring as a response to global warming in the Washington, DC, area Biodiversity Conservation, 10, 597–612. Beaubien EG, Freeland HJ (2000) Spring phenology trends in Alberta, Canada: links to ocean temperature. International Journal of Biometeorology, 44, 53–59. Chuine I, Beaubien E (2001) Phenology is a major determinant of temperate tree range. Ecology Letters, 4, 500–510. Cleland E.E., Chuine I. et al. (2007). Shifting plant phenology in response to global change, TRENDS in Ecology and Evolution, 22 (7) 357-365 IPCC (2007) Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge, UK and New York, NY, USA. Lieth, H. (1974) Purposes of a Phenology Book. In: Lieth, H. (ed) Phenology and Seasonality Modeling, Ecological Studies 8. Springer, New York, 444 pp. Morin X., Lechowicz M.J., Augspurger C., O’Keefe J. Viner D., Chuine I. (2009). Leaf phenology in 22 North America tree species during the 21st century. Global Change Biology, 15 961-975. Sherry, B.A. Zhou, H., et al. (2007). Divergence of reproductive phenology under climate warming. PNAS January 2, 2007 vol. 104 no. 1, 198–202 Impacts of climate change on plant phenology in temperate and boreal forests of N. America Amalesh Dhar* 1 , Andrew Park 2 ,Susanne Kames 2 1 Mixedwood Ecology and Management Program, University of Northern British Columbia, 3333 University Way, Prince George, BC, Canada V2N 4Z9 2 Center for Forest Interdisciplinary Research, Department of Biology, University of Winnipeg, 515 Portage Ave. Winnipeg, MB, R3B 2E9 (*Corresponding author : [email protected] ) Location Species Time period Change in first flowering Reference North America American elm 1956-1997 ~ - 8 days Chuine et al. (2000) Canada Aspen 1901–1997 - 26 days Beaubien & Freeland (2000) Canada Trembling aspen, chokecherry, serviceberry 1936–2000 - 8 days Beaubien & Freeland (2000) United States 89 Species 1970-1999 - 4.5 days Abu-asab et al.(2001) US northeast American beech, sugar maple, yellow birch 1957–2004 -5 to10 days Richardson et al (2006) United States 11 Species 1970-1999 +3 to 10 days Abu-asab et al.(2001) Future challenges • A major effort to collect phenological data across N. America is needed to improve model parameterization. • Eddy-covariance techniques have potential to link ecosystem function with species-level phenology. • In areas where lack long-term ground-based phenological observations, robust phenological models could be used to simulate past, present and future species phenology over wide areas, and these predictions could be compared with remotely sensed data. • More robust parameterization of leaf senescence, drought response and frost damage are needed. • Effects of moisture stress, seasonality of precipitation and rising CO 2 need to be integrated with temperature effects. Current response to warmer temperatures • Empirical studies from North America and Eurasia demonstrate that the growing season of trees has been extended in temperate and boreal zones. • Date of first flowering has advanced by 3 – 26 days, depending on species (Table 1). • First flowering of trembling aspen in Alberta advanced by ~ 26 days, an apparent response to long distance teleconnection between warming surface waters in the northern Pacific and higher atmospheric temperatures in western Canada (Figure 1). Table 1: Phenological changes in selected tree species. Phenology modelling and prediction. • Process-based models (PBMs) are the most robust of the modelling approaches being used to project future phenology. • PBMs attempt to integrate physiological processes with multiple environmental variables to produce a near-comprehensive model of phenological response to the total environment. • For example, PHENOFIT (Figure 4) uses five climatic variables to project 12 phenological outputs, including frost injury, date of fruiting and probability of producing viable seeds (Chuine and Beaubien, 2001). Figure 4. Structure of PHENOFIT. • PHENOFIT results suggest that the realized niches of trembling aspen and sugar maple are equivalent to their fundamental niches. Range restrictions were projected to be due to inability to fully develop functional leaves and flowers (Chuine and Beaubien, 2001). • A process-based model of leaf unfolding showed that temperate forest trees displayed idiosyncratic responses to different GCM global warming scenarios in the north and south of their ranges (Morin et al, 2009) (Figure 5). Figure 5. Responses of leaf unfolding date in temperate trees to (A) 3.5 o C and (B) 1.0 o C temperature rise by 2100. Ag – Aesculus glabra, Fn – Fraxinus nigra, Jn – Juglans nigra, Os – Ostrya virginiana, Pt – Populus tremuloides, Sn – Salix nigra. Negative numbers = earlier phenology. Phenophases and Climate Change. Many of the effects of a warmer climate are likely to be felt primarily through altered timing of phenology or a mismatch between climatic signals and phenology, which could result in failure to complete a given phenophase. Temperature sensitivity of budburst and flowering has resulted in these phenological events being among the first documented fingerprints of climate change (Menzel et al., 2006). Improved phenological predictions are needed to better estimates of future ecosystem productivity, project changes in dominance in multi-species forest stands, and to provide foresters with criteria that can be used to select tree provenances with the best chances of adapting to the future climate.
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Transcript of 24th Congress for Conservation Biology, Canada 2010
Figure 1: Long-term trend (1901–1997) in first-flowering dates of Aspen in Alberta (adapted from Beaubien
and Freeland (2000).
Divergence of Community Bloom Patterns
In a controlled warming experiment, Sherry et al. (2007) report that early-flowering grass and herb species flowered earlier, while late-summer flowering species flowered later than in the control (Figure 2). Simulated warming therefore significantly affected the temporal overlap of reproductive stages between successively blooming species.
Figure 1: Divergence in flowering date of 12 herbaceous and graminoid species (Sherry et al, 2007).
Phenological consequences of climate change.
• The earth’s average surface temperature may increase by 1.4 to 5.8°C between 1990 and 2100, with greater increases in northern latitudes (IPCC 2007).
• Average spring temperatures in Canada increased by 1.4 °C between 1948 and 1999 with greater warming in winter / spring .
• Projected temperature increases of 2 to >10 °C for Canada by 2100, depending on model scenario (Lemmen et al, 2008) (example in Figure 3).
• Potential for reduced snow cover, late-winter warming, thaw-freeze events, extended growing season, increased evapotranspiration, altered precipitation patterns.
Figure 3. Projected temperature changes under scenario IS92a of the Canadian Climate Model (Environment Canada, date?)
Phenological consequences of these changes may include:
• Earlier and/or abnormal leaf unfolding in the event of failure to complete chilling requirements (Morin et al. 2009)
• Seasonality: Shifts in flowering and seed set to both earlier and later than long-run averages could occur (Figure 2).
• Longer growing seasons, which may translate into increased primary production. Productivity is also contingent, however, on concurrent changes in precipitation, seasonality and CO2
concentrations.
• Frost damage: Earlier bud break and later senescence may expose plants to damaging frosts in the spring, and incomplete resorption of foliar N in the autumn (Norby et al., 2003). Frost damage may also reduce seed production, which may have demographic consequences.
• Range extensions or contractions may occur. Range extension may be facilitated by extension of favourable climate out of current range. Range contraction over time if climate shifts beyond adaptive envelope of key phenophases (e.g. seed germination).
Factors Influencing Plant Phenology
The timing of phenophases is thought to be under strong genetic control, leading to regionally adapted ecotypes that are influenced by:
Temperature: Leaf unfolding and budburst respond strongly to temperature.
Frost: If late season frosts occur after budburst or flowering, reproductive failure and reduced growth of the tree in that season can occur (ref).
Chilling: Full winter dormancy may require periods of chilling that includes super-cooling and dessication of cell protoplasm.
Photoperiod: Photoperiod initiates dormancy adaptation in latitudinally adapted tree ecotypes.
Evapotranspiration: increased surface temperature and likely reduced summer precipitation
Drought: Seasonal drought during the growing season which lead to reduce the growth of the tree.
What is Phenology?
Phenology is defined as the study of the timing of recurring biological phases of an organism, including the biotic and abiotic causes of this timing, and the interrelationships of phenophases among species (Lieth, 1974).
Phenology is a dominant, often overlooked aspect of plant ecology, from the scale of individuals to whole ecosystems (Cleland et al. 2008). Important phenological events for plants include:
• Bud burst and Leaf unfolding,
• Flowering and setting fruit
• Autumn or dry season leaf drop, and
• The related processes of winter hardening and breaking dormancy.
Selected ReferencesAbu-Asab, M., Peterson, S., Stanwyn, P.M., Shelter, G. and Sylvia, S., (2001) Earlier plant flowering in
spring as a response to global warming in the Washington, DC, area Biodiversity Conservation, 10, 597–612.
Beaubien EG, Freeland HJ (2000) Spring phenology trends in Alberta, Canada: links to ocean temperature. International Journal of Biometeorology, 44, 53–59.
Chuine I, Beaubien E (2001) Phenology is a major determinant of temperate tree range. Ecology Letters, 4, 500–510.
Cleland E.E., Chuine I. et al. (2007). Shifting plant phenology in response to global change, TRENDS in Ecology and Evolution, 22 (7) 357-365
IPCC (2007) Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge, UK and New York, NY, USA.
Lieth, H. (1974) Purposes of a Phenology Book. In: Lieth, H. (ed) Phenology and Seasonality Modeling, Ecological Studies 8. Springer, New York, 444 pp.
Morin X., Lechowicz M.J., Augspurger C., O’Keefe J. Viner D., Chuine I. (2009). Leaf phenology in 22 North America tree species during the 21st century. Global Change Biology, 15 961-975.
Sherry, B.A. Zhou, H., et al. (2007). Divergence of reproductive phenology under climate warming. PNAS January 2, 2007 vol. 104 no. 1, 198–202
Impacts of climate change on plant phenology in temperate and boreal forests of N. America
Amalesh Dhar*1, Andrew Park2,Susanne Kames2 1Mixedwood Ecology and Management Program, University of Northern British Columbia, 3333 University Way, Prince George, BC, Canada V2N 4Z9
2Center for Forest Interdisciplinary Research, Department of Biology, University of Winnipeg, 515 Portage Ave. Winnipeg, MB, R3B 2E9 (*Corresponding author : [email protected] )
Location SpeciesTime period
Change in first flowering Reference
North America American elm 1956-1997 ~ - 8 days Chuine et al. (2000)
Canada Aspen 1901–1997 - 26 days Beaubien & Freeland (2000)
CanadaTrembling aspen, chokecherry, serviceberry
1936–2000 - 8 days Beaubien & Freeland (2000)
United States 89 Species 1970-1999 - 4.5 days Abu-asab et al.(2001)
US northeastAmerican beech, sugar maple, yellow birch
1957–2004 -5 to10 days Richardson et al (2006)
United States 11 Species 1970-1999 +3 to 10 days Abu-asab et al.(2001)
Future challenges
• A major effort to collect phenological data across N. America is needed to improve model parameterization.
• Eddy-covariance techniques have potential to link ecosystem function with species-level phenology.
• In areas where lack long-term ground-based phenological observations, robust phenological models could be used to simulate past, present and future species phenology over wide areas, and these predictions could be compared with remotely sensed data.
• More robust parameterization of leaf senescence, drought response and frost damage are needed.
• Effects of moisture stress, seasonality of precipitation and rising CO2 need to be integrated with temperature effects.
Current response to warmer temperatures
• Empirical studies from North America and Eurasia demonstrate that the growing season of trees has been extended in temperate and boreal zones.
• Date of first flowering has advanced by 3 – 26 days, depending on species (Table 1).
• First flowering of trembling aspen in Alberta advanced by ~ 26 days, an apparent response to long distance teleconnection between warming surface waters in the northern Pacific and higher atmospheric temperatures in western Canada (Figure 1).
Table 1: Phenological changes in selected tree species.
Phenology modelling and prediction.
• Process-based models (PBMs) are the most robust of the modelling approaches being used to project future phenology.
• PBMs attempt to integrate physiological processes with multiple environmental variables to produce a near-comprehensive model of phenological response to the total environment.
• For example, PHENOFIT (Figure 4) uses five climatic variables to project 12 phenological outputs, including frost injury, date of fruiting and probability of producing viable seeds (Chuine and Beaubien, 2001).
Figure 4. Structure of PHENOFIT.
• PHENOFIT results suggest that the realized niches of trembling aspen and sugar maple are equivalent to their fundamental niches. Range restrictions were projected to be due to inability to fully develop functional leaves and flowers (Chuine and Beaubien, 2001).
• A process-based model of leaf unfolding showed that temperate forest trees displayed idiosyncratic responses to different GCM global warming scenarios in the north and south of their ranges (Morin et al, 2009) (Figure 5).
Figure 5. Responses of leaf unfolding date in temperate trees to (A) 3.5oC and (B)1.0oC temperature riseby 2100. Ag – Aesculusglabra, Fn – Fraxinus nigra, Jn – Juglans nigra, Os – Ostrya virginiana, Pt – Populus tremuloides,Sn – Salix nigra. Negative numbers = earlier phenology.
Phenophases and Climate Change.
Many of the effects of a warmer climate are likely to be felt primarily through altered timing of phenology or a mismatch between climatic signals and phenology, which could result in failure to complete a given phenophase.
Temperature sensitivity of budburst and flowering has resulted in these phenological events being among the first documented fingerprints of climate change (Menzel et al., 2006).
Improved phenological predictions are needed to better estimates of future ecosystem productivity, project changes in dominance in multi-species forest stands, and to provide foresters with criteria that can be used to select tree provenances with the best chances of adapting to the future climate.
