Plant diversity-environment relationships in xeric grasslands of north-eastern Romania

Abstract

Dry grasslands are plant communities with major importance for biodiversity. In this study, xeric grasslands of the order Festucetalia valesiacae from North-Eastern Romania were analyzed, in 45 nested series, at seven grain sizes (0.0001-100 m2), sampled in 5 plant communities within above mentioned phytosociological unit. The aim was to test the relative importance of different environmental factors on species richness (α-diversity) and species turnover (β-diversity), the last one expressed as the exponent of the power-law species-area relationship, and to detect which is the influence of spatial scale on diversity-environment relationship. Generalized linear models were used to assess the relative importance of predictors in shaping diversity in all seven spatial scales. The results showed that diversity-environment relationships were dependent on the scale of analysis, different factors being influential at different spatial scales. Local environmental conditions and land use practices were more related to species richness while general soil characteristics explained a larger proportion of spatial species turnover. In conclusion, diversity-environment relationships in the xeric grasslands from North-Eastern Romania are scale dependent, with local factors more important at small spatial scales and soil parameters more important for larger scales.