2025/07/17 by Pekka Niittynen, Marija Merkurjeva, Julia Kemppinen · 1 voice
Earth and Planetary Sciences · #Climate change and permafrost
paper · doi:10.22541/au.175273038.82142110/v1
Leaf functional traits are informative of plant fitness and functions in ecosystems. These functional traits and their variation across geographic extents is much studied but less is known about their temporal variation, especially how phenology affects functional trait variation over a growing season. Here, we provide an analysis of the seasonal variation in six leaf functional traits of 11 sub-Arctic vascular plant species in northern Finland, highlighting significant temporal dynamics over a growing season. Our findings reveal that functional traits, including specific leaf area, leaf dry matter content, leaf area, leaf dry mass, brightness index, and greenness index, exhibit considerable variation across the 15-week growing season. These temporal variations are influenced by plant growth forms, with distinct patterns observed among forbs, deciduous shrubs, and evergreen shrubs. Our analyses show that the rank of species is rather well preserved through the growing season in the most commonly used traits, and for this reason, the timing of sampling has a rather minor impact on the relative trait differences across species. However, if different species are measured at different times of the year, the seasonal effect can be notable. The growth forms often followed roughly similar temporal dynamics, and therefore, the error can be especially strong when comparing species across different growth forms.