When management meets science: adaptive analysis for the optimization of the eradication of the Northern raccoon ( Procyon lotor )

AbstractThe EU Regulation no.1143/2014 on invasive species requires the EU Member States to respond promptly and efficiently in eradicating the invasive alien species listed as species of Union concern. The Northern raccoon (Procyon lotor) was introduced in Northern Italy along the river Adda and we carried out its eradication campaign between 2016 and 2019. We used an integrated approach of camera traps and live traps. A standardized approach to the camera trap survey (2904 camera trap-nights) revealed that the detectability of raccoons (0.27 ± 0.07 SD) increased in the proximity of the river and their occupancy (0.15 ± 0.09 SD) was higher in urban areas. These results allowed us to increase the trapping success whilst reducing the effort. During the captures, systematic collection of catch and effort data allowed to estimate population size (65 ± 7.8 raccoons) and thus to have a continuous update on how far the campaign was from the complete eradication of the species, allowing to adjust the trapping effort accordingly. We captured 69 raccoons (7279 cage trap nights) thanks to both systematic trapping and opportunistic activation of traps following stakeholders' reports. Stakeholders supported the campaign and some of them played an important role in reporting sightings, signs, and allowing access to their private land. Camera trap data also allowed us to make a Rapid Eradication Assessment that estimated an eradication probability of 99% after 6 months without detections. We finally give indications for future control campaigns on the species to increase removal success, reducing the effort

Dispersal and habitat cuing of Eurasian red squirrels in fragmented habitats.

5Animal dispersal and subsequent settlement is a key process in the life history of many organisms, when individuals use demographic and environmental cues to target post-dispersal habitats where fitness will be highest. To investigate the hypothesis that environmental disturbance (habitat fragmentation) may alter these cues, we compared dispersal patterns of 60 red squirrels (Sciurus vulgaris) in three study sites that differ in habitat composition and fragmentation. We determined dispersal distances, pre- and post-dispersal habitat types and survival using a combination of capture–mark–recapture, radiotracking and genetic parentage assignment. Most (75%) squirrels emigrated from the natal home range with mean dispersal distance of 1,014 ± 925 m (range 51–4,118 m). There were no sex-related differences in dispersal patterns and no differences in average dispersal distance, and the proportion of dispersers did not differ between sites. In one of the sites, dispersers settled in patches where density was lower than in the natal patch. In the least fragmented site, 90% of animals settled in the natal habitat type (habitat cuing) against 44–54% in the more strongly fragmented sites. Overall, more squirrels settled in the natal habitat type than expected based on habitat availability, but this was mainly due to individuals remaining within the natal wood. In the highly fragmented landscape, habitat cuing among emigrants did not occur more frequently than expected. We concluded that increased habitat fragmentation seemed to reduce reliable cues for habitat choice, but that dispersing squirrels settled in patches with lower densities of same-sex animals than at the natal home range or patch, independent of degree of fragmentation.openWauters, L.A.; Verbeylen, G.; Preatoni, D.; Martinoli, A.; Matthysen, E.Wauters, LUCAS ARMAND; Verbeylen, G.; Preatoni, Damiano; Martinoli, Adriano; Matthysen, E

No sex bias in natal dispersal of Eurasian red squirrels.

5siIn mammals, dispersal mostly takes place as juveniles or subadults before first reproduction. This so-called natal dispersal is usually sex-biased. Here we report dispersal distances and proportion of emigrants in three populations of Eurasian red squirrels (Sciurus vulgaris). Monitoring 32 males and 28 females, we showed that most squirrels emigrated and that proportions emigrants (69% males, 82% females) did not differ between the sexes. Also mean dispersal distance did not differ between males and females. Hence, there is no sex bias in the natal dispersal of red squirrels.reservedWauters, La; Preatoni, D; Martinoli, A; Verbeylen, G; Matthysen, EWauters, LUCAS ARMAND; Preatoni, Damiano; Martinoli, Adriano; Verbeylen, G; Matthysen, E

Living on the edge : morphological and behavioral adaptations to a marginal high-elevation habitat in an arboreal mammal

Habitats are characterized by different local environmental conditions that influence both behavior and morphology of species, which can result in habitat-dependent phenotypic differences among animals living in heterogeneous environments. We studied 3 alpine populations of Eurasian red squirrels (Sciurus vulgaris), 1 living in a marginal high-elevation habitat at the edge of the species' altitudinal distribution, and 2 occurring in higher-quality habitats. Here, we investigated whether squirrels living in the marginal area differed in 2 morphological parameters (body size and body mass) and/or in the expression of 4 personality traits estimated with an open field test and a mirror image stimulation test (activity, exploration, activity-exploration, and social tendency). Furthermore, we tested whether within-individual variance of the traits (behavioral plasticity) was higher in the edge habitat. Male squirrels in the edge habitat were smaller and weighed less than in the other study areas, while among females, size-habitat relationships were less marked. These sex-specific patterns were explained by a strong association between body mass and reproductive success in female squirrels. Squirrels in the marginal habitat were more active, explorative, and had a more social personality than in the other habitats. However, in contrast to our predictions, behavioral plasticity was smaller in the marginal habitat, but only for the trait exploration. Our results suggest that animals choose the habitat that best fits their personality, and that habitat-related differences in selective pressures may shape animals' morphology

The impact of urbanisation on chipmunks, arboreal and flying squirrels : a global systematic review

Abstract: The current, rapid urbanisation process impacts global biodiversity and can be a driver for phenotypic changes in mammals that persist in cities. Animals display different response strategies in urban environments compared to natural areas, but patterns may differ among species. To better comprehend this process, we focused on a limited number of species that are present in many urban green spaces around the globe.The aim of this systematic review is to investigate which response strategies chipmunks, arboreal and flying squirrels use to cope with urban environments, exploring whether there are general response patterns, and to reveal potential adaptations to life in urban areas. We included studies that compared trait differences among conspecifics living in different areas along an urbanisation gradient (rural-urban) and studies comparing individuals or populations between urban areas with different environmental characteristics.The effects of urbanisation on chipmunks, arboreal and flying squirrels, at the individual and at the population levels, were identified in nine topics. Included articles explored at least one of these topics and their key findings were described.Effects of urbanisation are evident in all considered topics. However, we found contrasting patterns between species or even among individuals of the same species studied in different geographical areas. Overall, we reported two knowledge gaps: some phenotypic traits were considered in few studies, and many species, especially those living in the Global South, where urban growth rate is higher, have not been studied.This systematic review suggests that urbanisation can be an important driver for adaptation in small mammals, underlining the complexity and differentiation of response patterns. Since target species have important ecological and social roles, additional comparative studies, increasing our understanding of processes that determine their presence in cities, are essential for urban green planning which aims to conserve biodiversity. imag

Rodents in the arena: a critical evaluation of methods measuring personality traits

6nonenoneMAZZAMUTO M.V., CREMONESI G., SANTICCHIA F., PREATONI D., MARTINOLI A., WAUTERS L.A.Mazzamuto, M. V.; Cremonesi, G.; Santicchia, F.; Preatoni, D.; Martinoli, A.; Wauters, L. A