Physiological Ecology of Dryland Biocrust Mosses

摘要: Soil biocrusts are assemblages of cyanobacteria, lichens, and mosses ubiquitous to arid semi-arid (dryland) systems that offer an array ecosystem services. crust taxonomically diverse, account for up 30 % cover, large contributions biogeochemical functionality, yet remain the least understood component community. Because selective pressures their growth environment, such species highly desiccation tolerant, with ability withstand loss most cellular water extended periods time, during which metabolism is suspended. Biocrust can also tolerate larger ranges temperature, light, content than mesic species, still sensitive certain aspects environmental alteration. For one, changes in precipitation regime likely heavily influence survival dryland mosses. Rainfall, occurring as discrete hydration systems, causes undergo wet-dry cycles result either a positive or negative carbon balance. Carbon balance be used measure performance individual rainfall events, metric long-term viability. Recent work suggests event magnitude plays role balance, does frequency seasonality events fall. stimulated by elevated CO2, may not acclimate photosynthetically enrichment. Interestingly, CO2 favor stress tolerance at expense biocrust moss, particularly high temperatures. Finally, despite low annual rates, nitrogen appears place physiological limitations on reproductive biology High levels deposition, however, have been shown cause toxicity, competitive exclusion vascular plants, reduce cyanosymbioses.