COMPETITION BETWEEN THREE LICHEN SPECIES USING A FACTORIAL EXPERIMENTAL DESIGN.

Area of Science:

• Ecology
• Botany
• Lichenology

Background:

• Foliose lichens are common on slate rock habitats.
• Understanding interspecific competition is crucial for lichen community structure.

Purpose of the Study:

• To investigate the competitive interactions between three common foliose lichen species.
• To determine if pairwise competition predicts outcomes in three-species mixtures.

Main Methods:

• Field-based factorial experiment using lichen fragments on slate.
• Two- and three-species mixtures were established.
• Growth and competitive success were assessed.

Main Results:

• Parmelia conspersa strongly outcompeted Parmelia glabratula ssp. fuliginosa and Physcia orbicularis.
• P. orbicularis weakly outcompeted P. glabratula.
• Interactions in three-species mixtures differed from pairwise predictions.
• P. glabratula and P. orbicularis showed enhanced growth with more competitors.

Conclusions:

• Pairwise competition does not fully predict outcomes in multi-species lichen communities.
• Complex competitive dynamics allow for the coexistence of these three foliose lichens.
• Well-lit rock surfaces may facilitate the co-occurrence of Parmelia conspersa, P. glabratula, and P. orbicularis.