Understory plant indicator values poorly perform at monitoring temporal changes in French forest soil chemical properties
Year: 2025
Type: article
Abstract: Understory plant communities are widely used to infer soil conditions through species indicator values (IVs), scores reflecting species’ ecological preferences for factors such as soil acidity, moisture, or nutrient levels. While their reliability to describe soil conditions along spatial gradients is well established, their ability to capture temporal changes in soil chemistry remains largely untested at both temporal and geographical scales. We combined 26 years of vegetation monitoring with two French national soil surveys (1993–1997; 2007–2012) across 102 permanent forest plots to assess the reliability of community soil indices (CSIs) as bioindicators of soil pH, carbon-to-nitrogen ratio (C/N), and extractable phosphorus. CSIs were computed by averaging species IVs for each plot and survey. Temporal dynamics of measured soil properties and CSIs were analyzed using mixed-effects models at the national scale, while local trends were estimated separately for each plot to directly compare measured and vegetation-inferred changes. CSIs showed strong spatial correlations with measured pH and C/N, but weaker relationships for phosphorus. In contrast, no significant coupling was found between temporal changes in CSIs and measured soil parameters, with frequent mismatches in both direction and magnitude at the plot level. Measured soil dynamics were mainly driven by initial edaphic conditions and stand age, whereas CSI dynamics responded primarily to canopy openness and anthropogenic disturbances such tree harvesting. These findings confirm the value of IVs for spatial bioindication but highlight their limited sensitivity for detecting long-term soil changes, especially where soil changes remain modest.
Source: Ecological Indicators
Authors: Robinson Ribémont, Jean–Luc Dupouey, Benoît Richard, Jonathan Lenoir, Iris Le Roncé, Vincent Boulanger, Didier Alard, Thérèse Beaufils, Carole Begeot, Sylvaine Camaret, Déborah Closset-Kopp, Emmanuel Corcket, Guillaume Decocq, Richard Eynard–Machet, François Gillet, Arnaud Mouly, Pascale Ruffaldi, Fabien Spicher, Erwin Ulrich, Manuel Nicolas, Estelle Langlois, Michaël Aubert
Language: English
Subfield: Ecology
Field: Environmental Science
Domain: Physical Sciences
SDG: Life on land
Open Access status: gold
Estimated APC paid: $3,650
OpenAlex ID: W4416949963