Facilitating comparable research in seedling functional ecology

Authors: WINKLER, DANIEL - Us Geological Survey (USGS); GARBOWSKI, MAGDA - University Of Wyoming; KOZIC, KEVIN - Martin Luther University; LADOUCEUR, EMMA - German Centre For Integrative Biodiversity Research (IDIV); Larson, Julie Elizab; MARTIN, SARAH - German Centre For Integrative Biodiversity Research (IDIV); ROSCHE, CHRISTOPH - German Centre For Integrative Biodiversity Research (IDIV); ROSCHER, CHRISTIANE - German Centre For Integrative Biodiversity Research (IDIV); SLATE, MANDY - University Of Colorado; KORELL, LOTTE - German Centre For Integrative Biodiversity Research (IDIV)

Submitted to: Methods in Ecology and Evolution
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/27/2023
Publication Date: 1/19/2024
Citation: Winkler, D.E., Garbowski, M., Kozic, K., Ladouceur, E., Larson, J.J., Martin, S., Rosche, C., Roscher, C., Slate, M.L., Korell, L. 2024. Facilitating comparable research in seedling functional ecology. Methods in Ecology and Evolution. 15(3):464-476. https://doi.org/10.1111/2041-210X.14288.
DOI: https://doi.org/10.1111/2041-210X.14288

Interpretive Summary: The seedling stage is a critical and vulnerable period of the plant life cycle influencing plant regeneration in natural and managed ecosystems. Frameworks exist to understand how different plant populations and species function based on leaf and root attributes, but the traits of seedlings and their role in performance are not well understood. This synthesis provides an overview of the current state of knowledge in seedling functional ecology, highlighting major knowledge gaps and describing key considerations for the design of future research in this field.

Technical Abstract: 1. Ecologists have worked to ascribe function to the variation found in plant populations, communities and ecosystems across environments for at least the past century. The vast body of research in functional ecology has drastically improved understanding of how individuals respond to their environment, communities are assembled and ecosystems function. However, with limited exceptions, few studies have quantified differences in plant function during the earliest stages of the plant life cycle, and fewer have tested how this early variability shapes populations, communities and ecosystems. 2. Drawing from the literature and our collective experience, we describe the current state of knowledge in seedling functional ecology and provide examples of how this subdiscipline can enrich our fundamental understanding of plant function across levels of organisation. To inspire progressive work in this area, we also outline key considerations involved in seedling functional research (who, what, when, where and how to measure seedling traits) and identify remaining challenges and gaps in understanding around methodological approaches. 3. Within this conceptual synthesis, we highlight three critical areas in seedling ecology for future research to target. First, given wide variation in the definition of a ‘seedling’, we provide a standard definition based on seed reserve dependence while emphasising the need to measure ontogenetic variation more clearly both within and following the seedling stage. Second, studies demonstrate that seedlings can be studied in multiple media (e.g. soil, agar, filter paper) and conditions (e.g. field, greenhouse, laboratory). We recommend that researchers select methods based on explicit goals, yet follow standard guidelines to reduce methodological noise across studies. Third, research is critically needed to assess the implications of different methodologies on trait measurement and compatibility across studies. 4. By highlighting the importance of seedling functional ecology and suggesting pathways to address key challenges, we aim to inspire future research that generates useful and comparable data on seedling functional ecology. This work is critical to explain variation within and among populations, communities and ecosystems and integrate this most vulnerable stage of plant life into ecological frameworks.