Calibrating ecological indicator values and niche width for a Mediterranean flora

Abstract

Bioindication of ecological variables such as humidity, temperature or pH by ecological indicator values of plants is a powerful tool for research in plant ecology, e.g. to detect early vegetation changes. Here, we provide a data set of ecological indicator values including niche width for an entire regional flora. We used an extensive data-base with floristic relevés from Southern France to recalibrate indicator values for light (L), temperature (T), continentality (K), air humidity (A), soil moisture (F), pH (R), productivity (N), soil texture (G), soil organic matter content (O) and salinity (S). Values were recalibrated using average values from co-occurring plants, enabling to develop indicator values for species not yet evaluated previously. Recalibrated values are on a continuous scale and we add standard deviation, median, first and third quartile for each indicator value. Linear regression of average indicator values against measured factors showed higher correlation with recalibrated values compared to original indicator values for temperature, pH and nitrogen, and comparable R 2 for moisture. Individual indicator systems performed better than a combination and applying different weighting procedures demonstrated the usefulness of inverse variance. We further illustrate graphically how recalibrated values and niche width increase ecological knowledge on plants.

Bridging the gap between microclimate and microrefugia: A bottom‐up approach reveals strong climatic and biological offsets

“…For future studies, we recommend monitoring a range of control plots at each site with varying aspects and elevations, to better characterize the unique characteristics of microrefugia in terms of climatic and biological variables. However, field observations from a range of botanical experts and floristic inventories clearly indicate that in our study, the climatic and floristic originalities lie in the microrefugia and not in control plots where communities and associated EIVs are rather common for the Mediterranean region (Saatkamp et al, 2022 ).…”

Climate change impacts on Mediterranean vegetation are amplified at low altitudes

“…We used the ecological indicator system for Italy (Pignatti et al, 2005) adapted for the study area (Saatkamp et al, 2022). Ecological indicator values provide independent data on mean niche positions of plants in gradients of temperature and soil moisture, according to plant ecological expert knowledge, independent from the observational data and period in our area.…”

“…We used the ecological indicator system for Italy (Pignatti et al, 2005) adapted for the study area (Saatkamp et al, 2022).…”

Landolt Indicator Values in Modern Research: A Review

“…Over the period of five years, only one work was aimed at calibrating the Landolt indicator values [96]. The researchers used an extensive database with floristic relevés from Southern France to recalibrate the indicator values using average values from co-occurring plants, which enabled them to develop indicator values for species that were not evaluated previously.…”