Do recolonising wolves trigger non-consumptive effects in European
ecosystems? A review of evidence
Abstract
Predators can affect ecosystems through non-consumptive effects on their
prey, which can lead to cascading effects on the vegetation. In
mammalian communities, such cascading effects on whole ecosystems have
mainly been demonstrated in protected areas, but the extent to which
such effects may occur in more human-dominated landscapes remains
disputable. With the recolonisation of wolves (Canis lupus) in Europe,
understanding the potential for such cascading processes becomes crucial
for understanding the ecological consequences of wolf recovery and
making appropriate management recommendations. Here, we investigate the
evidence for non-consumptive effects of wolves on their wild ungulate
prey and cascading effects on the vegetation in European landscapes. We
reviewed empirical studies reporting wild ungulate responses to wolves
involving spatio-temporal behaviour at large and fine spatial scales,
activity patterns, vigilance, grouping, physiological effects, and
effects on the vegetation. We reveal that non-consumptive effects of
wolves in Europe have been studied in few regions and with focus on
regions with low human impact and are highly context-dependent and might
often be overruled by human-related factors. Further, we highlight the
need for a description of human influence in NCE studies. We discuss
challenges in NCE research and the potential for advances in future
research on NCE of wolves in a human dominated landscape. Further, we
emphasise the need for wildlife management to restore ecosystem
complexity and processes, to allow non-consumptive predator effects to
occur.