phaidra.vetmeduni.ac.at o:4279 DOI 10.1016/j.scitotenv.2024.171336 Physiological stress response to urbanisation differs between native and invasive squirrel species Novel pressures derived from urbanisation can alter native habitats and ultimately impact wildlife. Coping with such human-driven changes might induce shifts in species phenotypic traits, such as physiological responses to anthropogenic stressors. Preadaptation to face those challenges has been suggested to favour settlement and spread of invasive alien species in urbanised areas which, consequently, might respond differently than ecologically similar native species to stressors posed by urbanisation. The activation of the hypothalamic-pituitary-adrenal (HPA) axis and the subsequent release of glucocorticoids (GCs) has been suggested to mediate responses to anthropogenic disturbance in vertebrates. Furthermore, intraspecific competition, in conjunction with stressors related to urbanisation, might affect invasive and native species physiological stress responses differently. Using a parallel pseudo-experimental study system we measured faecal glucocorticoid metabolite (FGM) concentrations of the native Eurasian red squirrel and the invasive alien Eastern grey squirrel along a rural-urban gradient and in relation to conspecific density. The two species responded differently to challenges posed by the synergic effect of urbanisation and intraspecific competition. Association of FGMs and conspecific density in native red squirrels varied between rural and suburban sites, potentially depending on differential HPA axis responses. In urban sites, this relationship did not differ significantly from that in rural and suburban ones. Conversely, invasive grey squirrels' FGMs did not vary in relation to conspecific density, nor differed along the rural-urban gradient. Improving knowledge about native and competing invasive species' physiological responses to anthropogenic stressors can support conservation strategies in habitats altered by man. Our findings suggested that the invasive squirrels might be preadapted to cope with these challenges in urbanised areas, potentially increasing their success under the future global change scenario. eng Faecal Cortisol Metabolites Urban Ecology Invasive Alien Species Intraspecific Competition Sciurus Vulgaris Sciurus Carolinensis 2025-07-22T10:03:02.482Z LOMv1.0 Author BEGIN:VCARD VERSION:3.0 N:Santicchia;Francesca; FN:Francesca Santicchia END:VCARD BEGIN:VCARD VERSION:3.0 N:Tranquillo;Claudia; FN:Claudia Tranquillo END:VCARD BEGIN:VCARD VERSION:3.0 N:Wauters;Lucas A; FN:Lucas A Wauters END:VCARD BEGIN:VCARD VERSION:3.0 N:Palme;Rupert; FN:Rupert Palme X-ORCID:https://orcid.org/0000-0001-9466-3662 END:VCARD BEGIN:VCARD VERSION:3.0 N:Panzeri;Mattia; FN:Mattia Panzeri END:VCARD BEGIN:VCARD VERSION:3.0 N:Preatoni;Damiano; FN:Damiano Preatoni END:VCARD BEGIN:VCARD VERSION:3.0 N:Bisi;Francesco; FN:Francesco Bisi END:VCARD BEGIN:VCARD VERSION:3.0 N:Martinoli;Adriano; FN:Adriano Martinoli END:VCARD https://w3id.org/kim/hcrt/scheme https://w3id.org/kim/hcrt/text Textdokument Text LOMv1.0 yes https://creativecommons.org/licenses/by/4.0 application/pdf 1479828 https://phaidra.vetmeduni.ac.at/o:4279 https://phaidra.vetmeduni.ac.at/api/object/o:4279/thumbnail LOMv1.0 discipline