Habitat stress initiates changes in composition, CO2 gas exchange and C-allocation as life traits in biological soil crusts

Biological soil crusts (BSC) are the dominant functional vegetation unit in some of the harshest habitats in the world. We assessed BSC response to stress through changes in biotic composition, CO2 gas exchange and carbon allocation in three lichen-dominated BSC from habitats with different stress l...

Full description

Bibliographic Details
Published in:The ISME Journal
Main Authors: Colesie, Claudia, Allan Green, T G, Haferkamp, Ilka, Büdel, Burkhard
Format: Text
Language:English
Published: Nature Publishing Group 2014
Subjects:
Original Article
Antarctic
The Antarctic
Antarc*
Antarctica
Online Access:http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4184013/
http://www.ncbi.nlm.nih.gov/pubmed/24694713
https://doi.org/10.1038/ismej.2014.47
Description
Summary:Biological soil crusts (BSC) are the dominant functional vegetation unit in some of the harshest habitats in the world. We assessed BSC response to stress through changes in biotic composition, CO2 gas exchange and carbon allocation in three lichen-dominated BSC from habitats with different stress levels, two more extreme sites in Antarctica and one moderate site in Germany. Maximal net photosynthesis (NP) was identical, whereas the water content to achieve maximal NP was substantially lower in the Antarctic sites, this apparently being achieved by changes in biomass allocation. Optimal NP temperatures reflected local climate. The Antarctic BSC allocated fixed carbon (tracked using 14CO2) mostly to the alcohol soluble pool (low-molecular weight sugars, sugar alcohols), which has an important role in desiccation and freezing resistance and antioxidant protection. In contrast, BSC at the moderate site showed greater carbon allocation into the polysaccharide pool, indicating a tendency towards growth. The results indicate that the BSC of the more stressed Antarctic sites emphasise survival rather than growth. Changes in BSC are adaptive and at multiple levels and we identify benefits and risks attached to changing life traits, as well as describing the ecophysiological mechanisms that underlie them.

Similar Items