Effects of traits, species identity and local environmental conditions on the assessment of interactions: insights from an alpine meadow community

The prediction that facilitation is the dominant interaction in physically stressful conditions has been supported by many but not all field studies. In the present paper, we tested the effects of the identity of species, the local environmental conditions and the currencies of performance measurement on such variation. Using contrasting two plots, six species, and up to five multiple traits, we comprehensively explored the effects of the above factors on the assessment of plant interactions in an alpine meadow of the Qing-Hai Tibetan Plateau. Additionally, we attempted to figure out the possible mechanisms underlying the responses observed. The data were analysed by both standard ANOVAs and multivariate statistics. Our results demonstrated that the response to the removal of neighbours was both species and trait specific, and the effect of the local environmental conditions was dependent on the species involved. The contrast between plots had crucial influence on the net interactions of Kobresia macrantha, but little effect on Elymus nutans. Regarding the abiotic conditions, neighbours had significant impact on soil temperature, moist and solar radiation. The results contribute to advance our knowledge on the potential underlying factors influencing the assessment of facilitation.