AME 80:61-75 (2017)  -  DOI: https://doi.org/10.3354/ame01836

ABSTRACT: Travertine-depositing headwaters are characterized by unique hydrochemical and geomorphological features that are reflected in specialized assemblages. We studied microphytobenthos of 14 spring-associated limestone (SAL) sites in 2 different geologic zones of Austria twice in a year to check if any spatial or temporal variations could be recognized. Multivariate statistics (cluster analysis, non-metric multidimensional scaling) did not reveal temporal differences. However, a geographical pattern was obvious, with sites of western Austria clearly separated from other locations. The 7 resulting groups are characterized by 22 indicator species such as Brachysira calcicola ssp. pfisteri and Cymbopleura subaequalis. In addition to the diatom taxa typical of SAL habitats (Delicata delicatula, Gomphonema lateripunctatum), the rare desmid Oocardium stratum was also found at 7 sites, including new discoveries at 3 sites. Canonical correspondence analysis showed that input variables anthropogenic disturbance, total phosphorus, sky openness, chloride concentration and calcium carbonate precipitation rate significantly influence algal species distribution. Some of these variables reflect anthropogenic impact and therefore suggest limited stability of SAL communities against pollution.

KEY WORDS: Spring · Headwater · Travertine · Tufa · Periphyton · Algae · Oocardium