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

Abstract

The 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.

Assessing occupancy and activity of two invasive carnivores in two Caribbean islands: implications for insular ecosystems

“…camera traps and acoustic recorders), has significantly facilitated the collection of ecological data and improved our understanding of species distribution and ecosystem interactions (Blumstein et al ., 2011; Aide et al ., 2013; Rich et al ., 2017; Steenweg et al ., 2017). Consequently, these methods are increasingly recognized as an important tool in species distribution modelling (Kéry, Guillera‐Arroita & Lahoz‐Monfort, 2013; Guillera‐Arroita, 2017; Guillera‐Arroita, Kéry & Lahoz‐Monfort, 2019; Mazzamuto et al ., 2020).…”

How Raccoons Could Lead to the Disappearance of Native Crayfish in Central Italy

“…The invasive population of the raccoon in Central Italy is exponentially increasing its range (Boscherini et al, 2020;Boncompagni et al, 2021). In our study area, raccoons show a wide ecological plasticity, mostly selecting the immediate surroundings of watercourses for feeding and for denning; moreover, its dispersal is associated with rivers and valleys, which may increase the risk for crustaceans (Puskas et al, 2010;Mori et al, 2015;Mazzamuto et al, 2020). The raccoon has been found to actively predate on A. pallipes (Boncompagni et al, 2021), and our study confirms the impact of this invasive mammal on native crayfish: indeed, where the species is present, crayfish disappeared or their populations have been dramatically reduced in number, affecting their size distribution.…”

Climatic niche comparison of raccoons Procyon lotor and raccoon dogs Nyctereutes procyonoides in their native and non‐native ranges

“…in areas with a large number of individuals, and in areas at the edge of their distribution. Hunting and trapping of individuals is already common practice in many countries, but efficiency is highly dependent on population densities and the type of traps used (Dahl & Åhlén 2017, Mazzamuto et al 2020).…”