Distribution and ecology of high-mountain Solidago minuta (Asteraceae) in Poland

Solidago minuta L., a high-mountain species of the Solidago virgaurea group, occurs on some European mountain chains but it has been suggested that morphological differentiation of S. minuta is controversial due to the existence a wide range of morphologically intermediate plants between lowland S. virgaurea s. s. and high-mountain S. minuta. However, the recent study of this group revealed that both S. minuta and S. virgaurea are morphologically distinct taxa and that their most important taxonomical characters are those relating to the capitulum and florets. The aim of the present study is to verify the distribution of S. minuta in the Polish Carpathians and Sudetes and to identify the ecological characteristics of the species in relation to soil and vegetation. Solidago minuta was found most commonly in the Tatra Mts, but was also frequently encountered on Babia Gora Mt. and on the Karkonosze Mts. In the Tatra Mts, this species occurs most frequently in the subalpine belt, ascending in places to the alpine belt and descending in open areas to the upper montane belt. The preferred soils were acid, the pH mainly being between 3.5 and 5.0, and with relatively low nutrient content. Direct gradient analysis (CCA) revealed that the most important environmental variables explaining the general variability in species composition were altitude, as well as soil calcium content and soil acidity. S. minuta was found to occur mainly in communities of the Calamagrostietalia villosae order, growing amongst tall grass on lime-deficient substrata and grazed semi-natural vegetation, which here, in the subalpine belt, is widespread.