Modelling suitable habitat for Anastrophyllum donnianum in Jämtland, Sweden. Using the species distribution model Maxent.

Sammanfattning

Anastrophyllum donnianum, a liverwort species associated with the mixed northern liverwort heaths was recently (2023) found in Sweden for the first time. In order to conserve and manage the species and its habitat, knowledge about A. donnianum’s current distribution and ecology is necessary. Species distribution modelling (SDM) is a valuable tool to find suitable habitats and understand the ecological requirements for the habitats to exist. The aim of this study was to identify the environmental conditions for the suitable habitat of A. donnianum in the province of Jämtland, Sweden and to evaluate whether the species is dispersal or habitat limited in Jämtland. This was achieved by constructing a SDM with the Maxent model from Wallace, including both Sweden and Norway’s occurrence points from GBIF and five non-correlated environmental layers created by weather station data and digital elevation models. The results indicate that the most important factor for suitable habitat is humidity and rain frequency, where the suitability of habitat increases with higher moisture availability. It show that the suitable habitat for the species exists in mountainous north-facing areas with wet conditions and low sun exposure. The results also show that there are uninhabited highly suitable habitats (HSH) in Jämtland, with two hotspots south of the current known locations of A. donnianum. Additionally, the known Swedish occurrences were mainly found in a suboptimal habitat rather than HSH. The most important factors limiting the species is difficult to conclude only from the SDM, but the availability of suitable habitats suggest that dispersal is likely an important limitation. If the hotspots were to be visited in search of undiscovered populations, areas close to lake Anjan, Storrensjön or Storlien are recommended. Overall, the findings improve understanding of the ecological requirements and potential distribution of suitable habitat for A. donnianum in Sweden.