Changes in the onset of spring growth in shrubland species in response to experimental warming along a north–south gradient in Europe

Abstract

Aim To test whether the onset of spring growth in European shrublands is advanced in response to the warmer conditions projected for the next two decades by climate models, and, if there is a change, whether it differs across Europe. LocationThe studied sites spanned a broad north-south European gradient with average annual temperatures (8.2-15.6 ° C) and precipitation (511-1427 mm).Methods 'Bud break' was monitored in eight shrub and grass species in six European sites under control and experimentally warmer conditions generated by automatic roofs covering vegetation during the night.Results Species responsive to increased temperatures were Vaccinium myrtillus and Empetrum nigrum in Wales, Deschampsia flexuosa in Denmark, Calluna vulgaris in Netherlands, Populus alba in Hungary and Erica multiflora in Spain. Although the acceleration of spring growth was the commonest response to warming treatments, the responses at each site were species specific and year dependent. Under experimental warming 25% of cases exhibited a significantly earlier onset of the growing season and 10% had a significantly delayed onset of vegetative growth. No geographical gradient was detected in the experimental warming effects. However, there was a trend towards a greater dominance of phenological advances with more intense the warming treatments. Above 0.8 ° C warming, only advancements were recorded. Main conclusionsOur results show that warmer temperatures projected for the next decades have substantial potential effects on the phenology of the spring growth of dominant species in different European shrublands, with a dominant trend towards advancements the more intense the warming is. However, our study also demonstrates the overall difficulties of applying simple predictive relationships to extrapolate the effects of global change on phenology. Various combinations of environmental factors occur concurrently at different European sites and the interactions between different drivers (e.g. water and chilling) can alter phenology significantly.

Plant ecophysiological responses to drought, nocturnal warming and variable climate in the Pannonian sand forest-steppe: results of a six-year climate manipulation experiment

“…These results suggest that warmer periods in spring under predicted climate change will enhance the capacity of this species to convert light energy to fixed carbon. Springtime temperature limitation for P. alba is in line with the South Eurasian affinity of this species, and is supported by earlier budbreak in spring in warmed plots relative to control in the same experiment (Prieto et al 2009b). Consistent with our results, the negative impact of low temperature (or the positive influence of warming treatment) on photochemical performance (Fv/Fm) was reported for other thermophilous Insert Table 4 here.…”

Photochemical Reflectance Index (PRI) for Detecting Responses of Diurnal and Seasonal Photosynthetic Activity to Experimental Drought and Warming in a Mediterranean Shrubland

“…g S and Yield at midday were also lower in the warming treatment than under control conditions (p ≤ 0.01; Figures 4b and 5b). It has been reported that drought and warming can advance the spring growing season, affect reproductive performance and decrease plant productivity of E. multiflora [63,64]. The drier and warmer conditions projected for the future could affect diversity, decrease biomass and increase mortality in Mediterranean ecosystems [11,18,21,65].…”

Effects of night warming on spruce root around non-growing season vary with branch order and month

“…fine root biomass increased by warming, perhaps due to increased root number by warming during spring (Edwards et al 2004). Prieto et al (2009b) also found that the acceleration of spring growth was the most common response to warming and Soolanayakanahally et al (2013) proved that spring flush was primarily temperature driven, especially in boreal trees.…”