Floristic and community diversity of sub-alpine and alpine grasslands and grazed dwarf-shrub heaths in the Romanian Carpathians

Gheorghe Coldea,Vasile Cristea

doi:10.3989/pirineos.1998.v151-152.119

Abstract

Floristic diversity at community level and community diversity at landscape level are presented for the main grassland and dwarf-shrub communities in the sub-alpine and alpine zones in five mountain ranges of the Romanian Carpathians. The 30 plant communities studied had their floristic composition and distribution determined by geological substratum and pedo-climatic factors. The most diverse grasslands ( Oxytropido-Elynetum, Seslerio haynaldianae-Caricetun ) were on calcareous substratum and on the mountain slopes ( Festucetum pictae ), whilst the lowest diversity was in the oligo-mesotrophic sub-alpine grasslands ( Scorzonero- Festucetum nigricantis, Alchemillo-Poetum alpinae, Violo-Nardetum ). The Shannon-Weaver diversity index for the communities increased almost linearly with the number of species per community, whilst community diversity in the five mountain ranges was a function of the number of communities per mountain range.

Highlights

Sub-alpine and alpine grasslands and dwarf-shrub heath communities occur at altitudes between 1700-2500 m a.s.l. in the Romanian Carpathians
Sub-alpine and alpine grasslands and dwarf-shrub communities are distinctly different in physiognomy from the saxicolous or chionophilous communities of the alpine zone
The 150 relevés had a total of 345 cormophytic species, 55% of the total number of cormophytic species in the alpine zone of the Carpathians (BELDIE 1967, COLDEA 1991)

Summary

Introduction

Sub-alpine and alpine grasslands and dwarf-shrub heath communities occur at altitudes between 1700-2500 m a.s.l. in the Romanian Carpathians. Sub-alpine and alpine grasslands and dwarf-shrub communities are distinctly different in physiognomy from the saxicolous or chionophilous communities of the alpine zone. Their distribution and diversity are influenced by geological and edaphic factors, topography, and climate (temperature, rainfall and wind). The sub-alpine and alpine grasslands are defined for the purposes of this study as all plant communities dominated by species of the Poaceae and Cyperaceae which are used in the summer as pastureland for sheep and horses. They comprise four main groups, namely sub-alpine grassland {Calamagrostion villosae), oligo-mesotrophic sub-alpine grasslands (Potentillo-Nardion), acid alpine grassland {Caricion curvulae) and calcicole alpine grassland {FestucoSeslerion bielzii). Dwarf-shrub heath communities include sub-alpine dwarfshrub and alpine prostate dwarf-shrub heath {Rhododendro-Vaccinion)

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Results