Brigitte Klug

Species pattern and genetic diversity of Trichoderma in a mid-European, primeval floodplain-forest

We investigated the occurrence and genetic diversity of Trichoderma in the river Danube national park, a primeval, riparian forest area located south-east of Vienna (Austria) which represents one of the last cases of an original European river-floodplain landscape. Forty-six strains were isolated and identified at the species level by analysis of morphological characters, by sequence analysis of their internal transcribed spacer regions 1 and 2 (ITS 1 and 2) of the rDNA cluster and--in some cases--a fragment of the translation elongation factor 1alpha (tef1) gene, and RAPD-analysis. Twenty-one strains were positively identified as T. harzianum, thirteen as T. rossicum, four as T. cerinum, two as T. hamatum, and one each as T. atroviride and T. koningii: four strains yielded two different ITS1 and 2 as well as tef1 sequence types, which were not alignable with any known species. Our studies show that they represent two new taxa of Trichoderma.

Renaturierung von subalpinen und alpinen Ökosystemen

Die grose Vielfalt an alpinen und subalpinen Okosystemen auf waldfreien Standorten stellt besonders hohe Anforderungen an Planung und Durchfuhrung von Renaturierungsmasnahmen. Zunehmende Meereshohe, starke Hangneigungen und extreme klimatische Verhaltnisse im Gebirge bedingen zudem seit jeher naturliche Erosionsprozesse. Die zahllosen menschlichen Aktivitaten der letzten Jahrzehnte, gepaart mit unzureichenden Begrunungsmasnahmen, erhohen dieses Risiko noch um ein Vielfaches: Gelandekorrekturen im Zuge von Skipistenbauten, Almrevitalisierungen, Forst- und Almwegebauten, Masnahmen zur Verbesserung der touristischen Infrastruktur oder Wildbach- und Lawinenverbauungen. Nur durch Verwendung von hochwertigem, dem Standort angepasstem Pflanzen-oder Saatgutmaterial in Kombination mit der passenden Begrunungstechnik kann dieser Bedrohung dauerhaft entgegengewirkt werden. Dabei sind folgende limitierende Faktoren besonders zu beachten.

Early Successions in the Floodplain of the Kamp River (Austria)

In 2002, large riparian parts of the river Kamp in Lower Austria were affected by a flood which eradicated almost all vegetation at the riverside. From 2003 to 2012 the authors documented early stages of succession at five specific sites with characteristic vertical and horizontal distances to the river. Phytosociological releves were performed. Ecological indicator values, life traits, diversity indices (species number, evenness) and Sorensen index were used to describe the development within this period. The results demonstrate that, after five years, succession had usually reached a stage where highly competitive species like Phalaris arundinacea or Alnus glutinosa dominate. The first year after the flood annuals, lots of them common ruderals, dominated. The second year a change to biennial species took place. This transition was paralleled by a numeral maximum of species in the second year. Differences were only evident at a site where vegetation had not been completely eradicated by the flood. At this site a rudimentary stage of annuals was directly followed by an increase of Phalaris arundinacea that had been formerly present as well. Succession dynamics were stronger where conditions did not favor competitive species, which led to higher evenness values. Evenness values decreased, whenever Phalaris or Alnus achieved the dominance. As a matter of fact, these vegetation types showed a minimum in biodiversity. Maxima of evenness were found in vegetation with a high percentage of ruderals and short- living species.