Abstract
Facilitative effects and plant-plant interactions are well known for higher plants, but there is a lack of information about their relevance in cryptogams. Additional information about facilitative effects between bryophytes and lichens would be an important contribution to recent research on positive plant-plant interactions, as these can have striking influences not only on the organisation of early successional terrestrial communities but also on succession dynamics by kick-starting ecosystem development through the import of key nutrients. We investigated and quantified these mechanisms between Peltigera rufescens and its associated mosses. Moss-associated thalli had a different morphology that led to several benefits from the association. They had 66% higher net photosynthetic rate and, because the majority of the gas exchange of lichen thalli took place through the lower surface, there was a further increase as the CO2 concentration was > 25% higher beneath moss-associated thalli. Microclimatic measurements showed that mean light levels were substantially lower and temperature extremes slightly ameliorated for moss-associated thalli. As a consequence, desiccation was slower which is, together with an increase in thallus thickness and water storage, the reason for extended periods of optimal net photosynthesis for the moss-associated thalli. All these benefits combined to produce a growth rate of the moss-associated thalli which was significantly higher, twice that of non-associated thalli [0.75 +/- A 0.4 vs. 0.30 +/- A 0.1 mm/month (mean +/- A SD)]. This appears to be the first demonstration of a strong mechanistic basis for facilitative effects between lichens and bryophytes.
Original language | English |
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Pages (from-to) | 599-607 |
Number of pages | 9 |
Journal | Oecologia |
Volume | 169 |
Issue number | 3 |
DOIs | |
Publication status | Published - Jul 2012 |
Keywords / Materials (for Non-textual outputs)
- Association
- Ecosystem functioning
- Ecophysiology
- CO2 exchange
- Plant interactions
- CARBON-DIOXIDE EXCHANGE
- BIOLOGICAL SOIL CRUSTS
- CO2 CONCENTRATION
- PRIMARY SUCCESSION
- VASCULAR PLANTS
- NEGEV DESERT
- COMMUNITIES
- PRODUCTIVITY
- PATTERNS
- MOISTURE