More is not always better: Peat moss mixtures slightly enhance peatland stability

Species-poor peatlands challenge biodiversity–ecosystem function theory, which generally links high species diversity to stable ecosystem functions. An open question in ecosystem ecology is whether assemblages of naturally co-occurring peat mosses contribute to the stability of peatland ecosystem processes. We used a replacement series mesocosm experiment with mixtures of Sphagnum cuspidatum and S. medium to assess resistance, resilience, and recovery rates of net ecosystem CO2 exchange (NEE) under a mild and a deep water table drawdown event. Our results show a positive effect of mild water table drawdown on NEE with no apparent role for the composition of the peat moss assemblage. Our study indicates that the carbon uptake capacity by peat moss assemblages is rather resilient to mild water table drawdown, but seriously affected by deeper drought conditions. Co-occurring peat moss species seem to enhance the resilience of the carbon uptake function – i.e. ability of NEE to return to pr..., Early September 2021, we collected 40 cores (Æ 22.5 cm, 15 cm depth) of acrotelm peatmoss communities from a Sphagnum­-dominated peatland in the Store Mosse National Park, Sweden (57°17’54 N, 14°00’39 E). Our sampling strategy was set up to create a single-density replacement series (Jolliffe, 2000) with two naturally co-occurring Sphagnum mosses: S. cuspidatum Ehrh. ex Hoffm and S. medium Limpr. These species grow in close proximity to each other in the field and make up >70% (cover) of the field layer in the field site. Our sampling strategy resulted in cores with monocultures (100% cover) of S. cuspidatum or S. medium, and three mixtures of S. cuspidatum and S. medium – 75%/25%, 50%/50%, 25%/75% (n = 8). Final cover ratios may differ by ± 5%. Vascular plants were carefully removed
Following and acclimation period, the eight mesocosms for the five compositionally distinct Sphagnum communities were randomly assigned an experimental drought treatment: mild drought or deep drought (n ..., All data are .txt files and can be opened using the appended R script., **More is not always better: Peat moss mixtures slightly enhance peatland stability**

Early September 2021, we collected 40 cores (diameter 22.5 cm, 15 cm depth) of acrotelm peatmoss communities from a *Sphagnum­*-dominated peatland in the Store Mosse National Park, Sweden (57°17’54 N, 14°00’39 E). Our sampling strategy was set up to create a single-density replacement series (Jolliffe, 2000) with two naturally co-occurring *Sphagnum* mosses: *S. cuspidatum* Ehrh. ex Hoffm and *S. medium *Limpr*. *These species grow in close proximity to each other in the field and make up >70% (cover) of the field layer in the field site. Our sampling strategy resulted in cores with monocultures (100% cover) of *S. cuspidatum* or *S. medium*, and three mixtures of *S. cuspidatum* and *S. medium *– 75%/25%, 50%/50%, 25%/75% (n = 8). Final cover ratios may differ by ± 5%. Vascular plants were carefully removed

Following and acclimation period, the eight mesocosms for the five compositionally distinc...