Facilitation and interference in subalpine meadows of the central Caucasus

We studied the effects of neighbours on the biomass of seven randomly chosen species in species-rich sub-alpine meadows in the central Caucasus Mountains by comparing the performance of plants with neighbours removed experimentally to that of paired plants with their neighbours left intact. In most cases the removal of neighbours led to significant increases in vegetative and total above-ground biomass implying the species were limited by competition. However, the neighbour removal led also to an increased leaf wilting for target plants, as well as to strong decline in reproductive effort for some species. We hypothesise that competition may be the prevailing type of interaction in species-rich sub-alpine meadow communities, but competitive effects on vegetative production may be balanced, if not outweighed, by facilitation, at least for some species. Such a balance may enhance species coexistence in communities.