Effects of air pollutants on morphology and reproduction in four lichen species

CECILIA ESTRABOU; LAURA STIEFKENS; MIRIAM HADID; JUAN MANUEL RODRIGUEZ; ADRIANA PEREZ

Ecología en Bolivia

Instituto de Ecología UMSA

Lugar: La Paz; Año: 2004 vol. 39 p. 33 - 45

1605-2528

The effects of contamination on morphological and reproductive parameters of four lichen speciesin two urban areas and a control site were studied. The four lichen species studied have all beenpreviously identified as tolerant, resistant and sensitive to air pollution respectively. Thesespecies were sampled and collected from the bark of Melia azedarach L. (“paraíso”), situated in thecities of Córdoba, Río Cuarto and Río Ceballos. About 50 specimens for each species wereremoved. The following features were analyzed in each specimen: thallus color, cover andnumber of apothecia, soredia, necrosis of the thallus, changes in thallus size, thickness of lowerand upper cortex, algae number and a fertility index was built.In Ramalina celastri, a sensitive species, darkening and reduction of thallus size, the presenceof particulate matter and necrotic areas are some of the visible effects of air pollution. Physciaendochrysea, a resistant species, only shows minor changes in polluted areas. In resistant species,the fertility rate  shows a marked reduction in polluted areas. In Canomaculina pilosa, a tolerantspecies, a reduction in thallus size and darkening of both the thallus and soredia is evident.Necrotic areas are particularly obvious with this species as well. Physcia undulata exhibits thefewest alterations and greatest growth in urban areas. The most variable feature was the thicknessin the upper and the lower cortex. Algae number measured in lacunae along with he fertility indexresulted good indicators.