Advances in flowering phenology across the Northern Hemisphere are explained by functional traits

Abstract

Aim Numerous studies have reported changes in first flowering day (FFD‐changes) in response to changes in climate. However, regarding the direction (advances versus delays) and the intensity (number of days/decade) of FFD‐changes, species show differences even when observed in the same location. Here, we examine the extent to which plant traits can explain observed differences in the response of flowering phenology in trees, shrubs, herbs and grasses. Location Eighteen sites distributed over the Northern Hemisphere. Methods We compiled data from the literature on FFD‐changes over recent decades for 562 species (648 observations). We related FFD‐changes to predictor variables associated with (a) changes in climate, (b) local site conditions and (c) traits. Results Of all FDD‐changes, 80.4% were FFD‐advances, 69.9% not exceeding 5 days/decade, and 10.5% exceeding 5 days/decade, whereas 19.6% reported delays. The intensity of FFD‐advances could be explained by several predictor variables from all three groups (a–c). The importance of these variables differed between the growth forms. Overall, decreasing precipitation was more important than increasing temperature in explaining FFD‐advances. FFD‐advances were strongest in polar tundra and in dry and warm habitats. Traits related to competition and growth rate, like plant height, specific leaf area and leaf dry matter content, had substantial explanatory power in the models. Traits had the highest overall importance in trees and grasses. In herbs they were of equal importance with changes in climate. In shrubs, variables related to site conditions best explained the intensity of FFD‐advances. Main conclusions Plant traits are important to understand species‐specific and growth form‐specific differences in phenological responses to climatic changes. Hence, in future observations and predictions of plant phenology, traits should be taken into consideration, especially those related to competition and growth rate, as they improve our understanding of adaptations leading to phenological changes.

Desert‐like badlands and surrounding (semi‐)dry grasslands of Central Germany promote small‐scale phenotypic and genetic differentiation inThymus praecox

“…This study is in line with a broad range of literature showing phenotypic plant trait responses and genetic differentiation patterns to varying abiotic and biotic environmental conditions (e.g., Karbstein et al, submitted;König et al, 2018;Linhardt & Grant, 1996;Odat et al, 2004). In T. praecox, differentiation is probably promoted by site-dependent microhabitat differences mainly in light, temperature, and soil conditions.…”

“…Results indicate small‐scale phenotypic (morphological, functional) and genetic differentiation in T. praecox confirming our hypothesis of site‐dependent patterns due to different microhabitat conditions. This study is in line with a broad range of literature showing phenotypic plant trait responses and genetic differentiation patterns to varying abiotic and biotic environmental conditions (e.g., Bucher et al, ; Karbstein et al, submitted; König et al, ; Linhardt & Grant, ; Odat et al, ). In T. praecox , differentiation is probably promoted by site‐dependent microhabitat differences mainly in light, temperature, and soil conditions.…”

“…PCI (potential conductance index) is a measure of water-use efficiency (Holland & Richardson, 2009). Phenology, floral phenotype, and reproductive fitness also strongly depend on environmental conditions, for example, light intensity, temperature, and water availability (Dommée & Jacquard, 1985;König et al, 2018;Manicacci et al, 1996).…”

Phenology in a warming world: differences between native and non‐native plant species

“…Both observational and experimental studies document shifts in phenology in response to global warming, with many species advancing leaf‐out, flowering, or both (Arft et al ; Bradley et al ; Fitter & Fitter ; Dunne et al ; Parmesan & Yohe ; Menzel et al ; Cleland et al ; Jarrad et al ; Amano et al ; Hoffman et al ; Fridley ; Ovaskainen et al ; Whittington et al ; Thackeray et al ; König et al ; Zohner & Renner ). However, the direction and magnitude of these shifts differ, and some species exhibit delayed phenological responses to warming (Peñuelas et al ; Sherry et al ; Dunnell & Travers ; Cook et al ; Liancourt et al ) or no response to warming (Bradley et al ; Peñuelas et al ; Liancourt et al ; CaraDonna et al ).…”

Phenology responses of temperate butterflies to latitude depend on ecological traits

“…Analysing biotic assemblages based on species‐specific ecological traits offers a fruitful avenue to generalising observational patterns and disclosing mechanisms that generated them (König et al ; Wong et al ). For phenology, biochemical and physiological traits affecting, for example overwintering mortality (Vrba et al ), or adult thermoregulation (Kleckova et al ), will likely have a crucial role.…”