A test of local adaptation to drought in germination and seedling traits in populations of two alpine forbs across a 2000 mm/year precipitation gradient

Abstract

Seed regeneration is a critical stage in the life histories of plants, affecting species' abilities to maintain local populations, evolve, and disperse to new sites. In this study, we test for local adaptations to drought in germination and seedling growth of two alpine forbs with contrasting habitat preferences: the alpine generalist Veronica alpina and the snowbed specialist Sibbaldia procumbens . We sampled seeds of each species from four populations spanning a precipitation gradient from 1200 to 3400 mm/year in western Norway. In a growth chamber experiment, we germinated seeds from each population at 10 different water potentials under controlled light and temperature conditions. Drought led to lower germination percentage in both species, and additionally, slower germination, and more investment in roots for V. alpina. These responses varied along the precipitation gradient. Seeds from the driest populations had higher germination percentage, shorter time to germination, and higher investments in the roots under drought conditions than the seeds from the wettest populations – suggesting local adaption to drought. The snowbed specialist, S. procumbens , had lower germination percentages under drought, but otherwise did not respond to drought in ways that indicate physiological or morphological adaptions to drought. S. procumbens germination also did not vary systematically with precipitation of the source site, but heavier‐seeded populations germinated to higher rates and tolerated drought better. Our study is the first to test drought effects on seed regeneration in alpine plants populations from high‐precipitation regions. We found evidence that germination and seedling traits may show adaptation to drought even in populations from wet habitats. Our results also indicate that alpine generalists might be more adapted to drought and show more local adaptations in drought responses than snowbed specialists.

Registered Reports: A new chapter at Ecology & Evolution

“…The Gya et al (2023) experience inspired several additional Registered Reports in our lab (https://betwe enthe fjords.w.uib. no/home/), and this time around, the lead authors were MSc students (e.g., Birkeli et al, 2023).…”

“…Registered Reports are now increasingly being adopted across a range of STEM journals (e.g., Hardwicke & Ioannidis, 2018 ; Kiyonaga & Scimeca, 2019 ; Nosek & Lakens, 2014 ; https://www.nature.com/articles/d41586‐023‐00506‐2 ), so at this point, they are certainly not novel, but the journey to widespread usage among ecologists and evolutionary biologists is still in the early stages, with the first journal in the eco‐evo space only adopting them in 2017 (Foote, 2017 ). Ecology & Evolution has now published its first Registered Report (Gya et al, 2023 ), and the second is in the pipeline (Birkeli et al, 2023 ). As a journal, we are keen to see more Registered Reports in our field, given their numerous benefits and potential to eliminate many questionable research practices.…”

“…Below we discuss both the advantages and disadvantages Registered Reports can bring, by offering a perspective on (a) the publication process of Gya et al ( 2023 ) and (b) using Registered Reports as an educational tool. We hope to see more of this interesting article type in Ecology & Evolution and encourage researchers to get in touch to learn more.…”

“…The idea behind the first Registered Report published in Ecology & Evolution (Gya et al, 2023 ) was born from an unexpected opportunity—during summer, our team had collected an excess of seeds from global change experiments in Western Norway (see Vandvik et al, 2020 ) and were in search of a good use for them. A changing climate results in more extreme climate events, including droughts even in wetter alpine regions.…”

“…In Gya et al ( 2023 ), we expected drought adaptations in germination and seedling traits to be stronger in the driest population of both alpine species compared with the populations from wetter habitats. As we finalized the experiment, we saw that one species responded exactly as we had predicted, while the other did not.…”