Growth and Reproductive Dynamics of the Tropical Urban Lichen Pyxine petricola in Central Brazil

This study investigates the growth and reproductive strategies of the foliose lichen Pyxine petricola in the urban environment of Campo Grande, MS, Brazil, addressing a knowledge gap regarding its response to meteorological variation and urban environmental stressors. Over a two-year period, we monitored 13 individual thalli, analyzing growth dynamics, reproductive investment, and environmental associations. On average, thalli expanded more than 3.32 cm² per year and produced approximately 93 apothecia annually. Despite some individual variability, three thalli consistently exhibited high growth and reproductive output. Our results show that sexual reproduction in P. petricola does not necessarily reduce vegetative growth. Environmental variables-particularly total rainfall-were positively correlated with both thallus expansion and apothecia production. Additionally, lichen mortality mirrored host tree mortality, emphasizing the role of phorophyte viability. These findings offer novel insights into P. petricola's adaptive capacity in urban settings and reinforce the value of lichens as sensitive indicators for environmental monitoring.