Colonization, growth, and survival strategies of lichens on leaves in a subtropical rainforest

Rainforest leaves are a relatively short‐lived habitat which is well defined in both time and space, and which is occupied by a range of specialized lichens which might be expected to show survival strategies contrasting with those of other lichens. Changes in the lichen populations of individual leaves in subtropical rainforest at Ml Glorious, Queensland, Australia were observed for 1662 days. Over 1100 days elapsed before 50% of surviving leaves showed visible lichen thalli and the probability of colonization estimated from life tables did not exceed 0.42 ± 0.20 at any time. Porina epiphylla had a relative growth rate of 3.01 × 10 −2 mm 2 mm −2 week −1 , a high value for a lichen. The relative growth rate of Strigula subtilissima, however, was 6.86 × 10 −2 mm 2 mm −2 week −1 , the highest rate known for any lichen. Small size and high relative growth rates indicate that lichens on leaves have the most extreme ruderal strategy yet demonstrated amongst the lichens.