Proposal for an indicator plant species to monitor the winter distribution of Artiodactyls around the Shirakami Mountains based on dietary analysis of sika deer (Cervus nippon) and Japanese serows (Capricornis crispus)

Abstract

The habitat range of sika deer (Cervus nippon) has extended northward to the vicinity of the Shirakami Mountains, a designated World Natural Heritage Site. While food scar surveys have been utilized to monitor the presence or absence of sika deer, relying solely on food scars is inconclusive due to the cohabitation of the area by another Artiodactyl the Japanese serow (Capricornis crispus). To enhance survey effectiveness, it is crucial to identify plant species that can specifically indicate the presence of sika deer within this region. Therefore, we conducted a comparative analysis of the winter diets of these two Artiodactyla species, sika deer and Japanese serow, employing DNA metabarcoding analysis of feces. Our goal was to detect any differences in the species-specific diet between the two. The findings indicated that dwarf bamboo (Sasa kurilensis) and Pterocarya sp. were prevalent in the feces of sika deer, but absent in those of Japanese serows. Conversely, Aucuba japonica var. borealis and Japanese cedar (Cryptomeria japonica) were commonly consumed by both species. This analysis implies that basing a food scar survey on Sasa kurilensis would be the most effective indicator of the presence of sika deer in the study area during low-density periods.