We selected 15 sheep‐grazed sand pastures along a gradient of increasing grazing intensity
to study the fine‐scale patterns of main biomass fractions (green biomass, litter)
and that of plant species and functional groups (life forms and social behaviour types).
We classified them into five grazing intensity levels based on stocking density, proximity
to drinking and resting places and the number of faeces. We aimed to answer the following
questions: (i) How does increasing intensity of sheep grazing affect the amount of
green biomass, the species richness and their relationship in sand pastures? (ii)
How does increasing intensity of sheep grazing affect the biomass of perennial and
short‐lived graminoids and forbs? (iii) How does the disturbance value—expressed in
the biomass ratio of disturbance‐tolerant and ruderal species—change along the gradient
of grazing intensity? A unimodal relationship between green biomass and species richness
was detected; however, the ordination (canonical correspondence analysis, CCA) showed
no clustering of pastures subjected to the same levels of grazing intensity. Along
the grazing intensity gradient we found an increasing trend in species richness and
significant differences in green biomass (decreasing trend), litter (decreasing trend),
graminoids (decreasing trend) and short‐lived forbs (increasing trend). We found an
increasing amount of disturbance‐tolerant and ruderal species with increasing grazing
intensity. We suggest that we might need to use multiple scales for sampling and a
fine‐scale assessment of grazing intensity. Our findings might be instructive for
pastures in densely populated regions, which are prone to the encroachment of disturbance‐tolerant
and ruderal species.
