Disentangling effects of disturbance severity and frequency: Does bioindication really work?

Area of Science:

• Community ecology
• Plant ecology
• Bioindication

Background:

• Ecological disturbances significantly impact community attributes.
• Plant species exhibit varied responses to disturbance magnitude based on adaptations.
• Disturbance indicator values (DIVs) were proposed to describe plant niches along disturbance gradients.

Purpose of the Study:

• To assess the utility of DIVs for bioindication of disturbance regimes in riparian forests.
• To investigate the relationship between DIVs and longitudinal gradients representing disturbance severity and frequency.

Main Methods:

• Utilized a dataset of riparian forests in mountain catchments (Sudetes, SW Poland).
• Employed longitudinal position (upstream-downstream) as a proxy for disturbance regime.
• Calculated community-weighted means (CWMs) for six DIVs and analyzed their correlation with the longitudinal gradient.

Main Results:

• All analyzed DIVs unexpectedly increased along the downstream gradient.
• Severity indices demonstrated the strongest association with the longitudinal gradient.
• A significant correlation between disturbance severity and frequency indices was identified as a key challenge.

Conclusions:

• DIVs possess considerable applicative potential for bioindication.
• Distinguishing ecological niches for disturbance severity and frequency separately is difficult due to interacting factors.
• All DIVs integrate multiple attributes of the disturbance regime, including both severity and frequency.