Short-Term Impacts of the Air Temperature on Greening and Senescence in Alaskan Arctic Plant Tundra Habitats

May, Jeremy L.; Healey, Nathan C.; Ahrends, Hella Ellen; Hollister, Robert D.; Tweedie, C. E.; Welker, Jeffrey M.; Gould, William A.; Oberbauer, Steven F.

doi:10.3390/rs9121338

Cited by 12 publications

(23 citation statements)

References 47 publications

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“…This is supported by May et al. (), who found that warmer temperatures slowed, and cooler temperatures increased, the rate‐of‐senescence at short time scales (3 d). Despite warming air temperature, and soil temperature to a lesser extent, we did not observe slower rates of senescence in response to warming.…”

Section: Discussionsupporting

confidence: 56%

“…Similarly, near‐surface measurement of NDVI using a mobile sensor platform found senescence occurred later with warmer August temperatures (May et al. ). Early senescence may occur in water‐limited systems when conditions are dry, such as in grasslands (Liu et al.…”

Section: Discussionmentioning

confidence: 87%

“…, May et al. ). Senescence models used when estimating annual ecosystem carbon exchange commonly rely on photoperiod modified by a single climate driver, usually air temperature (Richardson et al.…”

Section: Discussionmentioning

confidence: 99%

“…Few Arctic studies have evaluated changes in rate-of-senescence in response to climate variables; however, warming is expected to induce slower rates of senescence (Estiarte and Peñuelas 2014). This is supported by May et al (2017), Notes: AIC c , Akaike's information criterion, corrected for sample sizes; CDD, cold degree-days; TDD, thaw degree-day. AIC c of the top model is 331.82.…”

Section: Change In Timing and Rate-of-senescencementioning

confidence: 96%

“…This is in contrast with landscape scale observations that have detected delayed senescence in the Arctic (Marchand et al 2004, Zeng et al 2011, Zhu et al 2012) and throughout the Northern Hemisphere (Jeong et al 2011, Liu et al 2016) using satellite-derived NDVI. Similarly, near-surface measurement of NDVI using a mobile sensor platform found senescence occurred later with warmer August temperatures (May et al 2017). Early senescence may occur in water-limited systems when conditions are dry, such as in grasslands (Liu et al 2016, Marchin et al 2018 or the high Arctic (Westergaard-Nielsen et al 2017).…”

Section: Change In Timing and Rate-of-senescencementioning

confidence: 97%

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Experimentally warmer and drier conditions in an Arctic plant community reveal microclimatic controls on senescence

et al. 2019

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The timing and duration of the plant growing season and its period of peak activity have shifted globally in response to climate change. These changes alter the period of maximum and potential total carbon uptake, especially in highly seasonal environments such as the Arctic. Earlier plant growth has been observed, and if plant senescence remains the same or is delayed, growing season extension will likely lead to greater carbon uptake and growth. We used phenology data from a multifactor climate change experiment to examine how altered seasonality influences the timing and rate‐of‐senescence and to compare direct observations of individual plant senescence with mathematical models of onset‐of‐senescence based on near‐surface remote sensing. Our three‐year experiment in an Arctic tundra ecosystem altered plant microclimates through factorial warming and earlier snowmelt treatments. We found that (1) early snowmelt and warmer temperatures led to earlier remotely sensed onset‐of‐senescence, but did not alter the rate‐of‐senescence, (2) the timing of color change for individual vascular plants did not change in response to the treatments, leading to a mismatch with remotely sensed phenology, and (3) cumulative, phenologically dependent microclimate metrics (e.g., soil cold degree‐days) best predicted the onset‐of‐senescence. Our study highlights the complexity of observing and understanding controls over phenological shifts that affect plant growth and consequently ecosystem functions. Experimental studies that include multiple approaches to observe and model phenological changes and microclimate are critical to develop phenological forecasting models.

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Section: Discussionsupporting

confidence: 56%

Section: Discussionmentioning

confidence: 87%

Section: Discussionmentioning

confidence: 99%

Section: Change In Timing and Rate-of-senescencementioning

confidence: 96%

Section: Change In Timing and Rate-of-senescencementioning

confidence: 97%

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Experimentally warmer and drier conditions in an Arctic plant community reveal microclimatic controls on senescence

et al. 2019

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Acclimation of subarctic vegetation to warming and increased cloudiness

Ndah,

Maljanen,

Kasurinen

et al. 2023

Plant Enviro Interactions

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Subarctic ecosystems are exposed to elevated temperatures and increased cloudiness in a changing climate with potentially important effects on vegetation structure, composition, and ecosystem functioning. We investigated the individual and combined effects of warming and increased cloudiness on vegetation greenness and cover in mesocosms from two tundra and one palsa mire ecosystems kept under strict environmental control in climate chambers. We also investigated leaf anatomical and biochemical traits of four dominant vascular plant species (Empetrum hermaphroditum, Vaccinium myrtillus, Vaccinium vitis‐idaea, and Rubus chamaemorus). Vegetation greenness increased in response to warming in all sites and in response to increased cloudiness in the tundra sites but without associated increases in vegetation cover or biomass, except that E. hermaphroditum biomass increased under warming. The combined warming and increased cloudiness treatment had an additive effect on vegetation greenness in all sites. It also increased the cover of graminoids and forbs in one of the tundra sites. Warming increased leaf dry mass per area of V. myrtillus and R. chamaemorus, and glandular trichome density of V. myrtillus and decreased spongy intercellular space of E. hermaphroditum and V. vitis‐idaea. Increased cloudiness decreased leaf dry mass per area of V. myrtillus, palisade thickness of E. hermaphroditum, and stomata density of E. hermaphroditum and V. vitis‐idaea, and increased leaf area and epidermis thickness of V. myrtillus, leaf shape index and nitrogen of E. hermaphroditum, and palisade intercellular space of V. vitis‐idaea. The combined treatment caused thinner leaves and decreased leaf carbon for V. myrtillus, and increased leaf chlorophyll of E. hermaphroditum. We show that under future warmer increased cloudiness conditions in the Subarctic (as simulated in our experiment), vegetation composition and distribution will change, mostly dominated by graminoids and forbs. These changes will depend on the responses of leaf anatomical and biochemical traits and will likely impact carbon gain and primary productivity and abiotic and biotic stress tolerance.

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