Discussion

In this study, it was found that the population dynamics of G. repens is strongly linked to the basal area of forests. Other key habitat factors influencing the species include stand age, moss species diversity, and the presence of canopy gaps. The habitats provided by most Swedish forests do not meet the needs of G. repens, which is consistent with the species’ population decline over the past 30 years. This aligns with trends observed in other forest-dependent species.

Basal area was the primary factor explaining the occurrence and colonization of G. repens, with the orchid favoring forests with higher basal area. Basal area and stand age were both used as variables in this study, and they correlate with each other. Basal area can be somewhat explained by the stand age, as the forest gets older and the trees grow, basal area increases. The study also found that gaps in the canopy and the number of moss species positively impacted G. repens. These gaps may provide the species with favorable conditions, potentially reducing the risk of extinction in such areas. Higher moss species richness was linked to lower extinction probabilities, suggesting that moss diversity contributes to a stable habitat for G. repens.

Soil moisture, however, had a negative impact, indicating that G. repens prefers drier soils. Ground inclination also showed a positive correlation with extinction probability, possibly due to the increased vulnerability of sloped forests to extreme weather conditions. The presence of bilberry positively affected colonization probability, this could have to do woth the association with bumblebees, which are important for G. repens pollination. Additionally, the connectivity of suitable habitats played a role in occurrence, as G. repens has limited dispersal capabilities.

In conclusion, to protect G. repens, forest management should consider maintaining older forests with higher basal areas and appropriate canopy gaps. Promoting species richness and connectivity between habitats will likely benefit G. repens and other species dependent on old-growth boreal forests.