Consistenza, distribuzione e dinamica di popolazione di Myricaria germanica (L.) Desv. nella Regione Trentino-Alto Adige/Südtirol

Myricaria germanica (L.) Desv. (German tamarisk) is a riparian bush associated to pioneer ecosystems of non-regulated rivers. M. germanica is an endangered indicator species of Alpine rivers that reflects riverine landscape diversity. In Trentino-Alto Adige/Südtirol Region M.germanica was historically common along alpine rivers, but during the last century damming and river regulation have interrupted the original riparian dynamics, reducing the German tamarisk natural habitats and today the species is endangered. This work describes the remnant populations of M. germanica in Trentino Alto Adige/Südtirol Region. The aim of this research was to assess the presence, vitality, and size of tamarisk’s populations and to investigate the relationship between their presence and the natural and anthropogenic factors shaping the river system. As a first step, we made an inventory of the known sites of M.germanica. The field surveys were carried out during the summer period of the years 2009-2014 and included most of the Trentino- Alto Adige/Südtirol rivers. Today, in all Trentino-Alto Adige/Südtirol Region, 10 sites have more than 100 German tamarisk plants and 20 have a few plants, often with no more than 10 plants, decreasing and without regeneration. In order to prevent extinction, the remnant populations should be adequately controlled. The maintenance and preservation of dynamic river conditions is the key for the conservation of M. germanica populations, otherwise the current disjunct distribution could become even more fragmented.