ORIGINAL ARTICLE: Can Ellenberg's indicator values for Mediterranean plants be used outside their region of definition?

Abstract

Aim The aims of this study are: (1) to explore the relationships between the Ellenberg indicator values (light, temperature and moisture) recently developed for two Mediterranean regions (Italy and Greece); and (2) to evaluate the possibility of using these values in other Mediterranean areas. Location Southern Greece and the Mediterranean part of Italy. Methods A global matrix containing 966 items of information (161 species × 3 indicator variables × 2 values assigned in each study, one in Italy and one in Greece) was constructed. A test of the accuracy of the values in predicting actual environmental conditions was provided using a detrended correspondence analysis (DCA) on published vegetation relevés from the Mediterranean region. The gamma statistic was used to express relationships of ecological indicator values between the two regions, and pairs of indicator values calculated for each species were compared using Wilcoxon matched pairs tests. Results The results showed that indices developed for Greece and Italy were not similarly correlated to sample scores along DCA axis 1. Species’ indicator values for Italy and for Greece were highly significantly correlated for light and moisture and significantly correlated for temperature, but the correlations were weak (0.20 ≤ gamma ≤ 0.31). Pairwise testing gave significantly different indicator values for the two regions. Discrepancies below or equal to 2 units on 9‐point scales (12 points for moisture) were found for 88%, 70% and 54% of the species respectively for light, temperature and moisture indices. A substantial number of species showed higher discrepancies, from 3 up to 6 units. Main conclusions In the light of the present work, it seems clear that the indicator values developed for Italy and for Greece should not be used outside the region for which they were defined. This constitutes additional evidence that indicator values can be influenced by the identity of potential competitors. It also underlines the need to use standardized methods for calibrating indicator values against measured variables in such a way that indicator systems can serve as general reference systems.

A test on Ellenberg indicator values in the Mediterranean evergreen woods (Quercetea ilicis)

“…Whereas the values and the use of mean values as surrogates for measured environmental factors are since long established as important tools in plant ecology in Central Europe, applications in the Mediterranean are scarce up to now. For this reason, their applicability in the Mediterranean region needs to be validated (Godefroid and Dana 2007), also because in such an heterogeneous patchwork of ecosystems there are many ways in which the conclusions drawn by the use of Eiv may be affected by their degree of accuracy and of suitability.…”

How robust are community-based plant bioindicators? Empirical testing of the relationship between Ellenberg values and direct environmental measures in woodland communities

“…While some work has been done on the robustness of the Ellenberg system, studies have generally focussed upon the relationship with other indicator systems (e.g. Godefroid and Dana, 2007) or the internal consistency in the Ellenberg system by comparing indicator values for species that co-occur (Ter Braak and Gremmen, 1987; 88 Hawkes et al, 1997). Somewhat surprisingly, relatively few studies have compared Ellenberg values to actual parameters.…”

Різноманіття Та Фітоіндикаційні Можливості Рослинного Угруповання

“…Види не є константними стосовно їх екологічних потреб, тому вони можуть мати різні індикаторні значення у різних частинах їх ареалу (Hill et al, 2000). Тому глобальні індикаторні системи не можуть бути надійні, що спонукає розробку локальних або регіональних індикаторних систем (Godefroid, Dana, 2007). Безпосереднє порівняння результатів біоіндикації з вимірюваними властивостями середовища вказує на наявність проблеми адекватності інтерпретації біоіндикації в термінах екологічних градієнтів (Schaffers, Sýkora, 2000;Wamelink et al, 2002Wamelink et al, , 2005.…”