Recovery of ciliate communities from an oligotrophic mountain stream after a catastrophic wind damage.

We studied the recovery of ciliate taxoceonoses in a mountain stream after a catastrophic windstorm that strongly affected mountainous regions of Slovakia in 2004. To this end, we analyzed changes in the community structure of ciliate assemblages from the Zubrovica stream in the Low Tatra Mts during the time frame between 2003 and 2008 by various statistical methods, including diversity and similarity indices, hierarchical clustering, multidimensional scaling, and PCA. The climax ciliate communities were characteristic for oligotrophic running waters, i.e., they were equitable (E(H) = 0.75-1.00) and harbored a comparatively low number of species (2-9) with typically low abundances (10-125 ind./ml). However, the community structure changed dramatically after the devastating windstorm. There was a significant increase of species number (10-30) and abundance (260-1480 ind./ml), concomitant with a decrease of the equitability (EH=0.43-0.83). These changed quantitative and qualitative community parameters wore off comparatively quickly, i.e., about six months after the catastrophic windstorm, the ciliate taxocoenoses had reached a community structure similar to that before the wind damage. The present observations and those from terrestrial habitats indicate that ciliate communities have a good capability to comparatively quickly reach a climax even after a strong disturbance.