Wolf predation as a regulator of the state of island populations of wild reindeer in the early 21st century

The relationship between the wolf and the wild reindeer in the Arctic has always been a focal point for researchers and northern Indigenous communities. This predator species continues to exert significant influence on wild reindeer and caribou inhabiting remote island territories, and adjacent mainland coastal areas in the 21st century. However, warming in the Arctic is leading to profound changes in the established principles governing the formation and functioning of both reindeer and wolf populations. Based on literature data and original research, all known island populations and groups of wild reindeer have been categorized according to their population dynamics, status (stable or declining), and the presence of predators within their ranges. For each group, the impact of wolves on reindeer has been analyzed across both stable and decreasing populations. Examples are provided of various deer groups existing in the absence of predation pressure, including those in archipelagos of the Southern Hemisphere. Additionally, the mechanisms of wolf influence on other ungulate species (such as moose) under conditions of insular isolation are discussed. As evidence of the diversity of ecological connections, herds of wild and domestic reindeer from Taimyr and northern Yakutia are analyzed. Four distinct types of “wolf-reindeer” system functioning are identified. Along with their prey (wild reindeer), wolves alter the spatial structure and utilize the full spectrum of available food resources influenced by the process of diminishing sea ice area. In modern conditions, the wolf is merely one link in the complex natural system of the Arctic, subject to various external regulatory influences. For wild reindeer, the wolf becomes a key factor capable of reducing population numbers only if the herd is already in a depressed state.