The impact of human land use and landscape productivity on population dynamics of red fox in southeastern Norway

Abstract

In the boreal forest, the red fox (Vulpes vulpes) is a key species due to its many strong food web linkages and its exploitation of niches that form in the wake of human activities. Recent altitudinal range expansion and a perceived population increase have become topics of concern in Scandinavia, primarily due to the potential impacts of red foxes on both prey and competitor species. However, despite it being a common species, there is still surprisingly little knowledge about the temporal and spatial characteristics of its population dynamics. In this study, we synthesized 12 years of snow-track transect data covering a 27,000-km 2 study area to identify factors associated with red fox distribution and population dynamics. Using Bayesian hierarchical regression models, we evaluated the relationships of landscape productivity and climate gradients as well as anthropogenic subsidies with an index of red fox population size and growth rates. We found that landscapes with high human settlement density and large amounts of gut piles from moose (Alces alces) hunting were associated with higher red fox abundances. Population dynamics were characterized by direct density-dependent growth, and the structure of density dependence was best explained by the amount of agricultural land in the landscape. Population equilibrium levels increased, and populations were more stable, in areas with a higher presence of agricultural lands, whereas density-dependent population growth was more prominent in areas of low agricultural presence. We conclude that human land use is a dominant driver of red fox population dynamics in the boreal forest. We encourage further research focusing on contrasting effects of anthropogenic subsidization on predator population carrying capacities and temporal stability, and potential impacts on prey dynamics.

Spatiotemporal patterns of red fox scavenging in forest and tundra: the influence of prey fluctuations and winter conditions

“…2), where carrion biomass is also much higher (Hagen 2014). Both these factors might, in addition to higher diversity and stability of other food sources, lead to more stable red fox abundance in forest habitats (Jahren et al 2020). Concurrently, increased activity at baits during winters with low rodent abundance may indicate a diet shift, as predicted by the FRH.…”

Scavenging patterns of generalist predators in forested areas: The potential implications of increase in carrion availability on a threatened capercaillie population

“…Carrion can occur in temporal pulses, or be scattered across extensive areas, and can act as a lifesaver for scavengers during the harshest periods. The spatiotemporal availability of carrion will influence the density, distribution, and diversity of scavengers (DeVault et al 2003;Mateo-Tom as et al 2015;Jahren et al 2020), affecting their survival and shifting their diets and feeding behaviour (Sel as & Vik, 2006;Newsome et al 2015). Accidental and intentional supplementary feeding of predators by humans (e.g.…”

“…Capercaillie populations have been in progressive decline throughout Europe (Storch, 2007;Jahren et al 2016;K€ ammerle et al 2017), beginning earlier in the south of their range and especially sharply in the fragmented and threatened populations of the Iberian Peninsula (Storch, 2007;Gil, G omez-Serrano & L opez-L opez, 2020). This decline has been attributed to low reproductive success and recruitment due to variety factors, such as climate change, habitat loss and fragmentation, human disturbance and the impact of generalist predators (Storch, 2007;Moreno-Opo et al 2015;Jahren et al 2016Jahren et al , 2020K€ ammerle et al 2017). It has been suggested that the increase in generalist predator populations, such as the red fox and marten species, has been favoured by the increase in agricultural areas and human settlements, the lack of apex-predators, and especially by the increase in carrion from wild ungulates as well as conservation policies protecting mesocarnivores (Kurki et al 1998;Sel as & Vik, 2006;Jahren et al 2020).…”

“…This decline has been attributed to low reproductive success and recruitment due to variety factors, such as climate change, habitat loss and fragmentation, human disturbance and the impact of generalist predators (Storch, 2007;Moreno-Opo et al 2015;Jahren et al 2016Jahren et al , 2020K€ ammerle et al 2017). It has been suggested that the increase in generalist predator populations, such as the red fox and marten species, has been favoured by the increase in agricultural areas and human settlements, the lack of apex-predators, and especially by the increase in carrion from wild ungulates as well as conservation policies protecting mesocarnivores (Kurki et al 1998;Sel as & Vik, 2006;Jahren et al 2020). As well as taking adult birds, these species are known nest and chick predators and have been linked to negative impacts on the breeding success of capercaillie (Kahuala & Helle, 2002; Figure 1 Observed and potential effects derived from the increase in carrion availability on the threatened Pyrenean population of the western capercaillie (Baines et al 1996(Baines et al , 2016Côt e et al 2004;Storch, 2007;Jahren et al 2016;K€ ammerle et al 2017).…”

Evaluation of Spatio-Temporal Patterns of Predation Risk to Forest Grouse Nests in the Central European Mountain Regions

“…Altogether, the red fox and martens were responsible for more than one half of destroyed artificial nests (61%) which is in line with predation on real black grouse nests in Norway [ 77 ]. The increasing predation risk on forest grouse populations is more pronounced in recent decades due to increasing population trends of generalist mesocarnivores or corvid species, especially caused by land-use changes or legal protection [ 8 , 78 , 79 , 80 , 81 ].…”