Competitors alter selection on alpine plants exposed to experimental climate change
Abstract
Investigating how climate change alters selection regimes is a crucial step towards understanding the potential of populations to evolve in the face of changing conditions. Previous studies have mainly focused on understanding how changing climate directly influences selection, while the role of species’ interactions has received little attention. Here, we used a transplant experiment along an elevation gradient to estimate how climate warming and competitive interactions lead to shifts in directional phenotypic selection on morphology and phenology of four alpine plants. We found that warming generally imposed novel selection, with the largest shifts in regimes acting on specific leaf area and flowering time across species. Competitors instead weakened the selection acting on traits that was imposed directly by warming. Weakened or absent selection in the presence of competitors was largely associated with the suppression of absolute means and variation of fitness. Our results suggest that although climate change can impose strong selection, competitive interactions within communities might act to limit selection and thereby stymie evolutionary responses in alpine plants facing climate change.
README: Competitors alter selection on alpine plants exposed to experimental climate change
https://doi.org/10.5061/dryad.v6wwpzh30
The data derives from a transplant experiment performed along an elevation gradient in Switzerland from 2016-2019, where four alpine plant species where transplanted from high (2200) to three lower elevations either in the absence or presence of competitors. The dataset includes traits (stalk height, specific leaf area, flowering time and floral size) as well as information on survival, seed production and flowering for individuals across the experiment.
Description of the data and file structure
Explanation of columns in dataset:
- Column "Site" includes data on the experimental site to which plants were transplanted. "P" = 1400 m a.s.l., "M" = 1750 m a.s.l., "C" = 1950 m a.s.l. and "R" = 2200 m a.s.l.
- Column "Block" includes data on the experimental block to which plants were transplanted within each site (1-10)
- Column "Competition" includes data on the competitor treatment. "No_competition" = Competitors absent, "Competition" = Competitors present
- Column "Species" includes data on the focal species. "ant" = Anthyllis vulneraria, "tri" = Trifolium badium, "pla" = Plantago alpina, "cam" = Campanula scheuchzeri
- Columns "survival_xx" includes data on survival estimated 2017-2019 (1=alive, 0=dead)
- Columns "flowering_xx" includes data on flowering estimated 2017-2019 (1=flowering, 0=not flowering)
- Columns "seed_xx" includes data on estimated seed production estimated 2017-2019 (number of seeds)
- Column "F_TIME" includes data on flowering time (julian day) across 2017-2019
- Column "F_SIZE" includes data on banner size across 2017-2019 (millimeters)
- Column "FHLM" includes data on floral length across 2017-2019 (millimeters)
- Column "FHWM" includes data on floral width across 2017-2019 (millimeters)
- Column "S_HEIGHT" includes data on stalk height across 2017-2019 (millimeters)
- Column "L_NO" includes data on leaf number across 2017-2019
- Column "SLA" includes data on SLA across 2017-2019 (millimeters/g)
- NA values represents missing data that were be obtained during data collection
Code/Software
The analyses are presented in the following scripts:
- Obtaining fitness ("1_Obtaining fitness.R")
- Identifying Most Parsimonious Models (MPMs; "2_Identifying_MPMs.R")
- Estimating selection for Anthyllis vulneraria ("3_Estimating_selection_ant.R")
- Estimating selection for Trifolium badium ("3_Estimating_selection_tri.R")
- Estimating selection for Plantago alpina ("3_Estimating_selection_pla.R")
- Estimating selection for Campanula scheuchzeri ("3_Estimating_selection_cam.R")
- Estimating fitness and trait means ("4_Estimating_fitness_trait_means.R")
- Estimating fitness and trait variation ("5_Estimating_fitness_trait_variation.R")
All steps of these analyses are described in the main text of the paper "Competitors alter selection on alpine plants exposed to experimental climate change" in Evolution Letters.