Emerging opportunities and challenges in phenology: a review

Abstract

Abstract. Plant phenology research has gained increasing attention because of the sensitivity of phenology to climate change and its consequences for ecosystem function. Recent technological development has made it possible to gather invaluable data at a variety of spatial and ecological scales. Despite our ability to observe phenological change at multiple scales, the mechanistic basis of phenology is still not well understood. Integration of multiple disciplines, including ecology, evolutionary biology, climate science, and remote sensing, with long-term monitoring data across multiple spatial scales is needed to advance understanding of phenology. We review the mechanisms and major drivers of plant phenology, including temperature, photoperiod, and winter chilling, as well as other factors such as competition, resource limitation, and genetics. Shifts in plant phenology have significant consequences on ecosystem productivity, carbon cycling, competition, food webs, and other ecosystem functions and services. We summarize recent advances in observation techniques across multiple spatial scales, including digital repeat photography, other complementary optical measurements, and solar-induced fluorescence, to assess our capability to address the importance of these scale-dependent drivers. Then, we review phenology models as an important component of earth system modeling. We find that the lack of species-level knowledge and observation data leads to difficulties in the development of vegetation phenology models at ecosystem or community scales. Finally, we recommend further research to advance understanding of the mechanisms governing phenology and the standardization of phenology observation methods across networks. With the opportunity for "big data" collection for plant phenology, we envision a breakthrough in processbased phenology modeling.

Using Near-Infrared-Enabled Digital Repeat Photography to Track Structural and Physiological Phenology in Mediterranean Tree–Grass Ecosystems

“…Foliage amount in evergreen tree species remain relatively constant throughout the year, and they can utilize their vast root system to access the water deep within the soil [64][65][66]. By contrast, grasses are highly responsive to rainfall variations in rainy seasons as they tend to use water and nutrients in topsoil with dense shallow roots [11,67]. The yellowing grasses in senescence lose their vigor during the dry and hot summer.…”

Extreme winter warm event causes exceptionally early bud break for many woody species

“…, Tang et al. ), many early‐successional species also have dormancy requirements related to accumulation of GDD rather than photoperiod (Caffarra and Donnelly , Basler and Körner , Zohner et al. 2014; Fig.…”

“…In recent decades, altered timing of phenological events (Tang et al. ) particularly associated with the beginning (Chmielewski and Rötzer , Badeck et al. , Menzel et al.…”

Temperature-manipulated dynamics and phenology ofMindarus abietinus(Hemiptera: Aphididae) in commercial Christmas tree plantations in Québec, Canada

“…For the coming decades, an increase between 2.4°C and 4.6°C of the average annual temperature is predicted if greenhouse gas emissions continue at the current rate throughout the 21st century (Ouranos 2015). An increase in air temperature directly affects the natural history and physiology of poikilotherms such as M. abietinus (van Baaren et al 2010), possibly altering their performance relative to the host plant (Flores-Mejia et al 2014). Even though phenological plasticity can temper the effects of climate change on living organisms (Joschinski et al 2015), it could desynchronise the complex life cycles of insects such as M. abietinus and its host trees (Visser and Holleman 2001).…”