Dr. Jekyll and Mr. Hyde: How Different Ecosystem (Dis)Services Perspectives Alter Management Decisions of a Native Invasive Encroachment

ABSTRACT As a consequence of climate change, the encroachment of the native species Empetrum nigrum (crowberry) is exerting multifaceted effects on the Arctic socio‐ecological system in Norway. The native invader detrimentally affects the quality of the reindeer grazing land, yet is beneficial for carbon sequestration, that is, providing both ecosystem services and disservices. Though the Norwegian reindeer husbandry acknowledges the importance of pasture quality, the government has not adopted any quantitative indicator to evaluate the current situation. Employing optimal control in a bioeconomic model of three species—reindeer, vegetation, and crowberry—we explore the effectiveness of three controls: slaughter and feeding of reindeer, and burning crowberry, in the short run (5 years) and long run (30 years). Our study seeks to determine the optimal crowberry burning effort and assess whether incorporating carbon sequestration alters the preferred burning strategy. Our results emphasize the critical role of crowberry burning in rejuvenating vegetation, a key indicator of pasture quality, especially in the long run. Burning crowberry remains optimal when carbon sequestration is included, yet at a lower level than when this value is excluded. We also highlight the incorporation of a salvage value for the palatable pasture, advocating for a balanced approach to burning that optimizes economic net benefit while sustaining pasture quality. Incorporating salvage values into the social welfare function emphasizes both the potential future use and the preservation of the grazing pasture for future generations. Our results suggest that the decision‐maker should continue burning crowberry in the long run while taking into account the plant's carbon sequestration, to maximize social welfare.