Flowering phenological changes in relation to climate change in Hungary

Abstract

The importance of long-term plant phenological time series is growing in monitoring of climate change impacts worldwide. To detect trends and assess possible influences of climate in Hungary, we studied flowering phenological records for six species (Convallaria majalis, Taraxacum officinale, Syringa vulgaris, Sambucus nigra, Robinia pseudoacacia, Tilia cordata) based on phenological observations from the Hungarian Meteorological Service recorded between 1952 and 2000. Altogether, four from the six examined plant species showed significant advancement in flowering onset with an average rate of 1.9-4.4 days per decade. We found that it was the mean temperature of the 2-3 months immediately preceding the mean flowering date, which most prominently influenced its timing. In addition, several species were affected by the late winter (January-March) values of the North Atlantic Oscillation (NAO) index. We also detected sporadic long-term effects for all species, where climatic variables from earlier months exerted influence with varying sign and little recognizable pattern: the temperature/NAO of the previous autumn (August-December) seems to influence Convallaria, and the temperature/precipitation of the previous spring (February-April) has some effect on Tilia flowering.

Testing Plant Phenophase as Proxy: Sensitivity Analysis of First Flowering Data From the 19th Century

“…were shown by Szabó et al (2016) and Walkovszky (1998) among our examined species. In contrary their findings in the neighbourhood country, Hungary, we did not find linear trend in the flowering onset data -probably because our data were recorded during the 19th century when the impacts of human induced climatic changes were not yet as influential as in the late 20 th century.…”

“…Considering the quantification of the FO -T -NAO impact-system, we have also found that the flowering onset (FO) is primarily influenced by the heat conditions of the preceding period of flowering (Menzel, 2003;Szabó et al, 2016), and the impact of winter NAO was negligible. Based on our findings the majority of plants are affected most strongly by the mean bi-monthly or trimonthly temperatures prior to the date of flowering.…”

“…After transforming the Réaumur degrees into standard Celsius degrees, and completing quality control, the monthly averaged data sets were considered as local homogeneous time series. The teleconnection pattern of North Atlantic Oscillation (NAO) has also been involved into our analysis as winter NAO index (Jones et al, 1997; Climatic Research Unit database), since several studies (e.g., Menzel, 2003;Gordo and Sanz, 2010;Szabó et al, 2016) confirmed the indirect effect of winter NAO on the timing of plant phenophases.…”

“…The available studies from this region (e.g. Walkovszky, 1998;Varga et al, 2009aVarga et al, ,b, 2010Szabó et al, 2016) rely on phenological data series recorded at the second half of 20th century, which period is already significantly influenced by the warming spring (Pongrácz et al, 2011;Cramer et al, 2014).…”

Impact of Climate Variability on Flowering Phenology and Its Implications for the Schedule of Blossom Festivals

“…Since these blossom festivals are culturally and economically important events, they should be timed around specific phenophases, such as flowering date of cherry or peach trees [10]. In temperate regions, these phenophases are very sensitive to small changes in temperature [11][12][13]. The advancement in flowering dates is estimated as 1 to 12 days for each 1 • C increase in spring temperature [14][15][16].…”