Flowering patterns change along elevational gradients and relate to life-history strategies in 29 herbaceous species

Solveig Franziska Bucher,Christine Römermann

doi:10.1007/s00035-020-00231-w

Solveig Franziska Bucher, Christine Römermann

Open Access

https://doi.org/10.1007/s00035-020-00231-w

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Abstract

Patterns of flowering phenology, i.e. first and last flowering day (FFD and LFD) and flowering duration (FD) govern plant pollination and reproduction. Most research has focused on FFD whereas LFD, FD and second flowering events were neglected although they are crucial events. To assess whether flowering patterns change species-specifically with changing abiotic conditions and whether these are related to leaf persistence, reproduction and pollination syndrome, we monitored flowering phenology (including also second flowering events) of 29 herbaceous species along two elevational gradients ranging from 700 to 1800 m a.s.l. in two consecutive years. FFD was delayed with increasing elevation. LFD followed two alternative strategies: species which ceased flowering early in the season delayed LFD with increasing elevation, species which ceased flowering late did not change LFD. FD decreased with increasing elevation in most species. The timing of flowering phenology had strong influences on the intensity of change along the elevational gradient and other stages of flowering phenology. Many species showed a second flowering event which occurred irrespective of elevation, suggesting a link to unsuccessful pollination rather than temperature. Life history strategies helped explain patterns of flowering phenology and a species’ ability to track changes in abiotic conditions, e.g. evergreen species started to flower earlier than summer green species and insect-pollinated species were able to expand FD most. These findings give insight into species-specific changes in phenological patterns and thus plant performance with changing environment. They should be considered when assessing the consequences of environmental change at both the community and ecosystem level.

Highlights

Changes in patterns of flowering phenology, i.e. first and last flowering day as well as flowering duration have ecological and economic impacts on natural and agricultural landscapes (Waser and Real 1979; Rathcke and Lacey 1985; Ollerton and Lack 1998; Memmott et al 2007; Hovenden et al 2008)
First flowering day changed with elevation and the intensity of this change was highly species-specific, differing between both years but in general first flowering day (FFD) occurred earlier in lower elevations (Fig. 1a, Online resource 3, see Table 1 for mean values and Table 2 for statistical results)
The results showed that summer green species had later FFD and last flowering day (LFD) than evergreen species, whereas flowering duration (FD) did not differ between these strategies (Fig. 4; Table 3)

Summary

Introduction

Changes in patterns of flowering phenology, i.e. first and last flowering day as well as flowering duration (timespan between first and last flowering) have ecological and economic impacts on natural and agricultural landscapes (Waser and Real 1979; Rathcke and Lacey 1985; Ollerton and Lack 1998; Memmott et al 2007; Hovenden et al 2008). Alpine Botany (2020) 130:41–58 end of flowering (last flowering day, LFD) and flowering duration (FD) are not well studied (but see Rathcke and Lacey 1985; Bock et al 2014; Trunschke and Stöcklin 2017). The latter two phenological stages strongly affect pollination and reproductive success and are, crucial stages in the life-history of plant species. Results from previous studies are highly ambiguous concerning FD and report reductions and prolongations with warmer climates (Miller-Rushing et al 2007; Sherry et al 2007; Bock et al 2014)

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