Phenology in central Europe - differences and trends of spring phenophases in urban and rural areas

Abstract

In order to examine the impacts of both large-scale and small-scale climate changes (urban climate effect) on the development of plants, long-term observations of four spring phenophases from ten central European regions (Hamburg, Berlin, Cologne, Frankfurt, Munich, Prague, Vienna, Zurich, Basle and Chur) were analysed. The objective of this study was to identify and compare the differences in the starting dates of the pre-spring phenophases, the beginning of flowering of the snowdrop (Galanthus nivalis) and forsythia (Forsythia sp.), and of the full-spring phenophases, the beginning of flowering of the sweet cherry (Prunus avium) and apple (Malus domestica), in urban and rural areas. The results indicate that, despite regional differences, in nearly all cases the species studied flower earlier in urbanised areas than in the corresponding rural areas. The forcing in urban areas was about 4 days for the pre-spring phenophases and about 2 days for the full-spring phenophases. The analysis of trends for the period from 1951 to 1995 showed tendencies towards an earlier flowering in all regions, but only 22% were significant at the 5% level. The trends for the period from 1980 to 1995 were much stronger for all regions and phases: the pre-spring phenophases on average became earlier by 13.9 days/decade in the urban areas and 15.3 days/decade in the rural areas, while the full-spring phenophases were 6.7 days earlier/decade in the urban areas and 9.1 days/decade earlier in the rural areas. Thus rural areas showed a higher trend towards an earlier flowering than did urban areas for the period from 1980 to 1995. However, these trends, especially for the pre-spring phenophases, turned out to be extremely variable.

Impact of urban warming on earlier spring flowering in Korea

“…For example, negative trends of the shrub species were more apparent (−0.01 to −3.7 days 10 yr −1 for goldenbell and −0.1 to −3.9 days 10 yr −1 for azalea) than those of the tree species (−0.03 to −0.25 days 10 yr −1 for peach and −0.9 to −2.5 days 10 yr −1 for cherry). Larger shifts in the FFD of early blooming species than of late-blooming species has previously been suggested (Roetzer et al 2000), and this corresponds to the results for shrubs (early FFD) and trees (late FFD) in the present study (see Figure 5). Possibly the early blooming species require less thermal energy accumulation for blooming (which is shown in Section 3.3), and hence are more sensitive to early spring temperature change.…”

“…However, additional environmental factors could affect the vegetation-climate interaction, and plant's response to regional climate change might vary in different parts of the world. As an example, we compared our results with similar findings from Central Europe by Roetzer et al (2000). Figure 10 shows the trends of FFD from the present study and those from Central Europe, during the period of 1951-1995.…”

“…This has been widely observed by in situ phenological records for many species in many parts of the world; flowering dates of spring flowers in East Asia (Ho et al, 2006;Lu et al, 2006), Central Europe (Roetzer et al, 2000), as well as ragweed in USA (Ziska et al, 2003) have been found to have advanced from a few days to a couple of weeks during the last decades in the 20th century. Similar results have been obtained from studies based on satellite-derived greenness data.…”

Impact of climatic conditions on the reproductive phenological phases of European hazel (Corylus avellana L.) in Slovakia

“…In the years 1994-2013, the trend of flowering decreased to 2 days. The results of Roetzer et al (2000) are consistent with our findings, as they showed that 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 Date flowering linear trend Elevation is a surrogate of a set of meteorological elements (temperature, precipitation), which cause changes in the course of plant phenological phases. With the increasing elevation, flowering in the elevation zones was unevenly delayed by 1 to 15 days in the first period, and by 1-10 days in the second period (Table 1).…”

“…This is reflected in its highly significant relation to the onset of spring phenological phases (Bednářová et al 2012;Škvareninová 2013). The reaction of the flowering phenophase was also distinct, since in the case of some tree species it has shifted by 14 days earlier over a long-term period (Roetzer et al 2000). In several parts of Europe, it has been observed that an average beginning of the growing season of forest tree species has shifted by 8 days earlier (Chmielewski, Rötzer 2001).…”