Parmotrema and Dirinaria appeared to be tolerant
lichens because of their survival in all plots, but they
showed different ecological patterns between the
plots. In this study, populations of Dirinaria were
conspicuous in plot 2 and 3 that are adjacent to main
and busy roads. But, the Dirinaria thallus average
coverage was shrinking from plot 1 to 3 (Figure
5), which might be an air pollution effect (Bates
2002). As a member of Physciaceae, Dirinaria is
often observed in urbanized areas (Sipman 2009).
Dirinaria picta and D. applanata can be found both
in rural and urban areas in lowland area (Saipunkaew
et al. 2006). Dirinaria also can still be found in
Jenderal Sudirman Street – Pekanbaru (highly traffic
density) (Nursal et al. 2005). Conversely, there were
no consecutive changing pattern of thallus number
and average coverage of Parmotrema from plot 1 to
plot 3 (increase or decrease), so that this genus cannot
be used as an indicator. Identification until species
level probably generate better result, considering that
in plot 1 and plot 2 we found P. tinctorum, which
is stated to be sensitive to air pollution in Japan
(Ohmura et al. 2009).