Habitat Ecology and Physiological Response of Sticta filix and Pseudocyphellaria delisei from Tasmania

Publisher Website
Google Scholar
Abstract
S. filix and P. delisei, 2 of the most widespread Tasmanian lichens, reach greatest dominance in areas of precipitation of approximately 1600 mm/yr. Both species occur on a variety of corticolous, terricolous and saxicolous substrates in areas with up to 300 mm/yr precipitation, but S. filix is absent where precipitation is less than 1200 mm/yr. Both species show a similar range of high thallus water holding capacity but P. delisei is more drought resistant due to its ability to photosynthesize at relatively low thallus water contents. Its low quotient of maximum CO2 fixation rate to dark respiration rate indicates a greater adaptation to cooler conditions. S. filix maintains a significantly higher rate of CO2 fixation on a chlorophyll basis, on a dry weight basis and on a unit area basis. Under saturated thallus moisture conditions the rate of photosynthesis in S. filix is reduced less from maximal levels than that of P. delisei. These factors, combined with the low light compensation point in S. filix, account for the relative dominance of S. filix in shady forest habitats and P. delisei in more open sites.

This publication has 4 references indexed in Scilit: