Spatio-temporal movement patterns and habitat choice of red foxes (Vulpes vulpes) and racoon dogs (Nyctereutes procyonoides) along the Wadden Sea coast

Abstract

Wetlands such as the World Heritage Site in the Wadden Sea include important habitats for breeding waterbirds. Its saltmarshes and adjacent conservation polders are used by thousands of breeding birds. However, some alarming population declines have been recorded during recent decades and previous studies found indications that predation pressure from red foxes (Vulpes vulpes) and more recently from invasive racoon dogs (Nyctereutes procyonoides) played an important role. The current study aimed to assess habitat utilisation by foxes and racoon dogs along the coast of the Wadden Sea. We equipped 21 foxes and seven racoon dogs with GPS collars and recorded a total of 37,586 (mean: 2,088) GPS fixes during a total of 2,617 (mean: 145) equipment days for red foxes and 3,440 (mean: 573) GPS fixes during a total of 272 (mean: 45) equipment days for racoon dogs. Foxes showed high individual variability in Kernel 95% home range sizes, with a mean of 172.2 ha (range: 3 to 824 ha) and little overlap among territories. Males had significantly larger home ranges than females, and there were no differences in home range sizes between adults (n = 14) and young (n = 4). Racoon dogs had smaller home ranges than foxes (mean: 52.8 ha). The preferred habitat type of both predators during daytime was the conservation polders along the Wadden Sea, while foxes also selected saltmarshes during the night. In contrast, both species avoided farmland areas. Foxes showed 20% of their activity during daylight hours and spent this time largely in areas with dense vegetation cover. None of the tagged individuals entered areas with particularly high bird densities (i.e. Wadden Sea islands or Halligen). However, our data suggest that foxes and racoon dogs frequently make use of linear structures such as dykes and dams and patrol along the tide line for carcasses. This suggests that at least single individuals of both species are prone to enter islands that are connected by dams to the mainland.

Diel and monthly activity pattern of brown bears and sika deer in the Shiretoko Peninsula, Hokkaido, Japan

“…In contrast, other small-to medium-sized mammals did not exhibit similar patterns. This may be partly due to the territorial features in some species, such as red foxes [50], which are less likely to share the same area with conspecifics. Also, even though they are not strictly territorial, small home ranges, e.g., in raccoon dogs [32], limit the number of individuals that are potentially observed at one camera-trap site.…”

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“…Uit andere onderzoeken aan gezenderde vossen in Nederland en Duitsland blijken territoriagroottes van gemiddeld ongeveer 150-170 ha (Baeyens, Van Breukelen & Bajramowic, 2000;Schwemmer, Weiel & Garthe, 2021). In één nacht (8u-periode) kunnen vossen makkelijk afstanden van zo'n 6 km afleggen (Baker et al, 2000).…”

How do invasive predators and their native prey respond to prescribed fire?

“…The occurrence and relative abundance (i.e. activity) of these predators can increase in response to prey abundance (Scroggie et al., 2018 ), recent burning (Birtsas et al., 2012 ; Doherty et al., 2023 ; Nalliah et al., 2022 ), and anthropogenic features (such as tracks and farms) that provide efficient movement and foraging opportunities in structurally complex environments like forests (Colón & Kamil, 2020 ; May & Norton, 1996 ; Schwemmer et al., 2021 ). Ecosystem‐specific knowledge of how invasive predators respond to these factors can assist land managers in developing more targeted strategies to effectively mitigate their impacts (e.g., McGregor et al., 2020 ).…”

“…We used camera traps to quantify mammal activity across 30 sites, both before and immediately after a prescribed fire at burnt and unburnt sites. We fitted generalised linear mixed models to test the following predictions: The invasive cat and fox will be more active at sites burnt by the prescribed fire (Hradsky, Mildwaters, et al., 2017 ; McGregor, Legge, et al., 2016 ), near anthropogenic features (Hradsky, Robley, et al., 2017 ; Schwemmer et al., 2021 ), and where mammalian prey activity is higher (Geary et al., 2022 ). Despite the increased availability of regenerating vegetation preferred for grazing (Klop et al., 2007 ; Reid et al., 2023 ), the native macropod community (kangaroos and wallabies) will show decreased activity in areas burnt by the prescribed fire, due to the increased risk of predation from foxes (Cherry et al., 2017 ).…”