Precipitation regime controls bryosphere carbon cycling similarly across contrasting ecosystems

In arctic and boreal ecosystems, ground bryophytes play an important role in regulating carbon (C) exchange between vast belowground C stores the atmosphere. Climate is changing particularly fast these high-latitude regions, but it unclear how altered precipitation regimes will affect dynamics bryosphere (i.e. moss layer including senesced moss, litter associated biota) closely upper humus layer, effects vary across contrasting environmental conditions. Here, we set up a greenhouse experiment which mesocosms were assembled containing samples of bryosphere, dominated by feather Hylocomium splendens, that collected from forest chronosequence northern Sweden varies strongly nutrient availability, productivity soil biota. We tested effect variation volume frequency on CO2 dissolved organic (DOC) export, growth. As expected, reduced lowered net efflux, DOC export However, moisture, lower layers often mediated interacted to drive dynamics. For example, less frequent growth only when was low. When high, high moisture content helped avoid desiccation. Variation regime affected cycling consistently chronosequence, despite large along sequence. This suggests exerts strong buffering at floor, leads similar responses external perturbations highly ecosystems. such, our study indicates projected increases droughts evapotranspiration regions resulting climate change reduce losses moss-dominated