ETD

• competition
• fire
• habitat disturbance
• rodent
• small mammal

Fires lead to a redistribution of resources and alteration of competitive dynamics through the structural modification of vegetation, thus indirectly affecting the spatial distribution of tree-dwelling small mammals. However, these aspects have seldom been studied, particularly in Mediterranean basin ecosystem and the arboreal species that inhabit it. Firstly, a systematic review was conducted to provide an overview of fire-related effects on arboreal small mammals in different forested biome worldwide. Following the PRISMA protocol, 71 studies were selected, resulting from a combination of two search approaches: a general one using general keywords and a specific one including the genera of the target species in the string. Despite the geographical and taxonomic biases, it was evidenced that when a wildfire occurs, arboreal small mammals express behavioural and physical responses, that favour their persistence. This is further facilitated by the vegetation, that is shaped to either resist or overcome the damage in fire-prone ecosystems. The main constraint to population persistence and viability resulted the degree of isolation of the affected area and the loss of key species-specific resources. In addition, threat factors are the occurrence of stand-replacing fires mainly in ecosystems lacking resprouting tree species (e.g. boreal forest, temperate coniferous forest) and altered fire regimes due to human intervention (e.g. Noth America). Thus, the review highlights how fire is a natural event that is part of an ecosystem-influenced regime to which tree-dwelling small mammals have adapted in different ways .
Secondly, my research work aimed to asses the spatial (vertical and horizontal distribution) and temporal habitat use of the garden dormouse (Eliomys quercinus), evaluating the effects of fire and interspecific competition with the red squirrel (Sciurus vulgaris) in shaping the short-term habitat use of this species in a Mediterranean environment. The study area was located in a mountain-hilly system of Monte Pisano (Tuscany, Italy) and comprised a forest affected by September 2018 mixed-severity fire, in addition to a nearly unburnt area. Sampling was carried during the late spring-summer 2021 in 50 randomly selected sites, which were stratified according to two factors: forest type and burn status. The occurrence of species in the two vertical layers were sampled using camera traps and hair tubes. The arboreality of the garden dormouse resulted only influenced by the habitat category: in the severely burnt pine forest the garden dormouse was mainly found on the ground, whereas for unburned forest type it displayed semi-arboreal habitat use. No effect of fire, environmental variables or competition was found to influence the distribution of garden dormouse. The activity pattern did not differ between burned and unburned areas. Although deeper investigation could improve our understanding of the interplay among post-fire ecosystem, fire severity and interspecific competition in shaping the garden dormouse habitat use, this study offers valuable insights into the ecological-behavioural aspects of a declining dormouse. Understanding these dynamics is critical for conservation strategies targeting arboreal small mammals in fire-prone Mediterranean landscapes.