Ground lichen cover and response in relation to forest characteristics in Sweden 1993–2023

Reindeer husbandry is closely connected to the culture and tradition of the indigenous Sami people, and ground lichens are a key bottleneck resource for winter grazing of the semi-domesticated reindeer. Many factors have been linked to the decrease in ground lichens in the boreal zone. Forestry plays a crucial role in the lichen decline in Swedish forests but is also an important actor with the potential to contribute to a recovery. Forestry is obliged to consider the needs of reindeer husbandry, but important details in the dynamics of how forest measures affect lichen cover are still unknown.Our analysis of environmental monitoring data shows that ground lichen cover declined by 57 % in the reindeer husbandry area from 1996 to 2015, while there was no declining trend from 2015 to 2021. Comparing lichen cover change for different age classes of forest, we found that lichen cover increase primarily occurred in clear-cut forest and forest aged < 40 years. Our results support previous findings that it is possible to increase lichen cover through adapted forest management. A basal area below 15 m2ha−1 in suitable lichen habitat will increase lichen cover for forest aged 40–80 years. The results of this study can contribute to increasing the knowledge basis for policy decisions, forest management, and local consultations between reindeer herders and forest companies to increase and restore lichen cover.