The temperature acclimation potential of tropical bryophytes.

Area of Science:

• Ecology
• Plant Physiology
• Tropical Biology

Background:

• Bryophyte diversity and biomass decrease with decreasing altitude in tropical forests.
• High temperatures in lowlands may limit montane bryophyte survival due to respiratory carbon losses.
• Limited acclimation capacity of montane species to warmer temperatures is hypothesized.

Purpose of the Study:

• To investigate the short-term and long-term acclimation of tropical bryophytes to warmer lowland temperatures.
• To assess the impact of transplantation on survival, growth, and CO2 exchange rates.
• To understand the potential for local adaptation in bryophyte populations facing climate change.

Main Methods:

• Transplantation of ten bryophyte species from 1200m and 500m to 500m and sea level in Panama.
• Monitoring of CO2 exchange for short-term temperature acclimation over 2.5 months.
• Evaluation of survival and growth rates over a 21-month period.

Main Results:

• No significant short-term acclimation of CO2 exchange was observed.
• Transplanted bryophytes exhibited higher mortality and lower growth rates compared to controls.
• Some individuals of most species survived and recovered growth rates, indicating potential long-term acclimation.
• Acclimation compensated for reduced CO2 uptake periods due to faster drying.

Conclusions:

• Montane bryophytes exhibit limited immediate temperature acclimation but show potential for longer-term adaptation.
• Dispersal and establishment limitations may explain the low abundance of these species in lowland forests.
• Heterogeneity in acclimation suggests potential for local adaptation, enabling populations to cope with climatic warming.