Skip to main content
SLU publication database (SLUpub)
Research article - Peer-reviewed, 2010

Species-specific activation time-lags can explain habitat restrictions in hydrophilic lichens

Lidén, Marlene; Jonsson Cabrajic, Anna V.; Ottosson Löfvenius, Mikaell; Palmqvist, Kristin; Lundmark, Tomas

Abstract

Photosystem II (PSII) activation after hydration with water or humid air was measured in four hydrophilic and a generalist lichen to test the hypothesis that slow activation might explain habitat restriction in the former group. For the hydrophilic species, activation was after 4 h nearly completed in Lobaria amplissima and Platismatia norvegica, while only c. 50% for Bryoria bicolor and Usnea longissima. The generalist Platismatia glauca was activated instantaneously. The effect of this on lichen field performance was investigated using a dynamic model separating the two water sources rain and humid air. Model simulations were made using the species-specific characteristics and climate data from 12 stream microhabitats. For U. longissima, slow PSII activation could reduce realized photosynthesis by a factor of five. Bryoria bicolor was almost as severely affected, while P. norvegica displayed moderate reductions. Lobaria amplissima displayed longer realized activity periods even in unfavourable microclimates, possibly because of a higher water loss resistance. Both close proximity to streams and presence of turbulent water had a positive impact on realized activity among the slowly activated species, coinciding with observed distribution patterns of hydrophilic species. The results presented here may thus partly explain observed habitat restrictions of rare hydrophilic lichens.

Keywords

Bryoria bicolor; Lobaria amplissima; Platismatia glauca; Platismatia norvegica; Usnea longissima; hydrophilic epiphytic lichens; photosynthesis; photosystem II activation; suboceanic distributional patterns; water relations

Published in

Plant, Cell and Environment
2010, Volume: 33, number: 5, pages: 851-862
Publisher: WILEY-BLACKWELL PUBLISHING, INC