Climate change fingerprints in recent European plant phenology

Abstract

A paper published in Global Change Biology in 2006 revealed that phenological responses in 1971–2000 matched the warming pattern in Europe, but a lack of chilling and adaptation in farming may have reversed these findings. Therefore, for 1951–2018 in a corresponding data set, we determined changes as linear trends and analysed their variation by plant traits/groups, across season and time as well as their attribution to warming following IPCC methodology. Although spring and summer phases in wild plants advanced less (maximum advances in 1978–2007), more (~90%) and more significant (~60%) negative trends were present, being stronger in early spring, at higher elevations, but smaller for nonwoody insect‐pollinated species. These trends were strongly attributable to winter and spring warming. Findings for crop spring phases were similar, but were less pronounced. There were clearer and attributable signs for a delayed senescence in response to winter and spring warming. These changes resulted in a longer growing season, but a constant generative period in wild plants and a shortened one in agricultural crops. Phenology determined by farmers’ decisions differed noticeably from the purely climatic driven phases with smaller percentages of advancing (~75%) trends, but farmers’ spring activities were the only group with reinforced advancement, suggesting adaptation. Trends in farmers’ spring and summer activities were very likely/likely associated with the warming pattern. In contrast, the advance in autumn farming phases was significantly associated with below average summer warming. Thus, under ongoing climate change with decreased chilling the advancing phenology in spring and summer is still attributable to warming; even the farmers’ activities in these seasons mirror, to a lesser extent, the warming. Our findings point to adaptation to climate change in agriculture and reveal diverse implications for terrestrial ecosystems; the strong attribution supports the necessary mediation of warming impacts to the general public.

The fingerprints of climate warming on cereal crops phenology and adaptation options

“…Numerous methods have been utilized to elucidate the intensity of the effect of climate change on agronomic cereal crops. The methods include analysis of satellite images on vegetation greenness, measurement of net primary production with Normalized Difference Vegetation Index (NDVI), and particularly, determination of temporal and spatial variations in phenological seasonality 26,79,[110][111][112][113][114][115] . The data on stages and phases of cereal crop phenology and climate meteorological data are collected from phenological networks or through designated observation stations.…”

“…Thus the asymmetric and opposing response of phenology to daytime and night-time was studied by Wang et al 82 and concluded that T max and night-time T min had opposite effects on the timing of start of the season, delayed end of the season and prolonged length of growing season. Furthermore, several earlier studies documented that the intensity of the response of phenological stages and phases of agricultural crops to warming trend is variable at spatio-temporal scales 79 , 83 , 84 . Phenology is well known climate change indicator.…”

“…Crop phenology is the most significant feature of crop adaptation, and spatial and temporal changes in phenological stages and phases provide well-built indications of the biological influence of thermal trend. Change in phenological seasonality is having both direct and indirect effects on natural vegetation and cereal crop productivity 25,26,[79][80][81] . Measured climate-warming trends have been implicated as a reason for accelerated cereal crop growth rates and reduced growing durations.…”

Chilling and Forcing From Cut Twigs—How to Simplify Phenological Experiments for Citizen Science

“…Additional cues associated with spring phenological events for some species include autumn temperature (Heide, 2003;Sparks et al, 2020), day length (Heide, 1993a;Heide, 1993b;Körner and Basler, 2010;Basler and Körner, 2012;Laube et al, 2014a), light quality (Brelsford and Robson, 2018), air humidity (Düring, 1979;Laube et al, 2014b;Zipf and Primack, 2017), or nutrient availability (Jochner et al, 2013a). Under natural in situ conditions it is difficult to disentangle these multiple and often co-varying environmental factors (e.g., Piao et al, 2019;Menzel et al, 2020).…”

Finnish National Phenological Network 1997–2017: from observations to trend detection

“…The changes in the annual cycle of plants are closely linked to the seasonal course of temperature, light and water supply, among other factors, and phenological observations constitute direct evidence of plants’ responses to these changes. With these regards, phenological data contribute tangibly to our understanding of global change biology (Menzel 2000 , 2002 ; Parmesan and Yohe 2003 ; Piao et al 2019 ; Menzel et al 2020 ). In Europe, the plant phenological data have demonstrated an average advance of spring/summer 2.5 days per decade between the years 1971 and 2000, in accordance with instrumentally observed warming (Menzel et al 2006 ).…”