Forage offering and seasonal intake comparisons to evaluate European rabbit threat in Nothofagus forests of southern Patagonia

Abstract

Background The European rabbit (Oryctolagus cuniculus L. 1758) was introduced into different regions of the world, generating significant trade-offs that critically impacted native vegetation. Here, we evaluate the rabbit's forage intakes in three vegetation types (forests, shrublands, and grasslands) along the four seasons in a temperate forest landscape in Southern Patagonia and discuss the potential threats over native vegetation. We formulated the following questions: (i) what is the forage offer at each vegetation type? (ii) what is the rabbit's forage intake and how it varied across the seasons along the year? and (iii) which vegetation types and plant life forms were more used according to the rabbit's forage intakes? Methods We censused understory vegetation to characterize the forage offer at each vegetation type and determined seasonal dietary intakes using microhistological analysis of pellets. The plant species identified in the field were grouped according to life form classes (tree regeneration, shrubs, forbs, graminoids, orchids, ferns, bryophytes, and hemiparasites). Data were analysed through uni- and multi-variate analyses, determining relationships between forage offer and the rabbit's forage intakes. Results Forage intakes revealed changes in plant life form consumption across vegetation types, where intake pressure was considerably different for tree regeneration (p = 0.001), graminoids (p = 0.001), and hemiparasites (p = 0.001). Besides, significant changes in consumption among seasons were detected for shrubs (p = 0.001), ferns (p = 0.030), and hemiparasites (p = 0.002). Although many species play an important role in the rabbit's forage intake networks (e.g., Chiliotrichum diffusum, Holcus lanatus), the strongest intake linkages were found in exotic grasses (e.g., Poa pratensis and Festuca sp.), native hemiparasites (e.g., Misodendrum sp.), native shrubs (e.g., Empetrum rubrum), and native trees (e.g., Nothofagus sp.). The summer and autumn seasons presented higher intake compared to the winter and spring seasons. Furthermore, hemiparasites intake (e.g., Misodendrum sp.) suggests that rabbits utilize different forage sources depending on the vegetation types. Conclusions Rabbits regularly inhabit the forest, even though it is not their preferred vegetation type to live. Rabbit management entails isolating regions that are more favourable to intake and emphasizing the year's season for rabbit control efforts.

The nutritional strategy of European rabbits is affected by age and sex: Females eat more and have better nutrient optimisation

“…Although, as previously stated, it is the most concrete way of measuring the chemical composition of the European rabbit's diet. It is interesting to mention that the dispersion of this very cosmopolitan species makes it, especially the study of the different responses in these Mediterranean ecosystems, so expanding this study to areas of the southern hemisphere would give a more global vision of the response of this animal (Huertas Herrera et al, 2022).…”

The ecological role of the European rabbit in the Magellanic/Fuegian ecosystem of southernmost Chile

“…The long history of rabbit invasion means that it has become an integral part of the Magellanic/Fuegian ecosystem, interacting with species at different trophic levels, simultaneously being prey, competitor, and herbivore (Correa-Cuadros et al 2022. Rabbits in continental Magallanes and neighboring Tierra del Fuego Island consume plant biomass and generate important negative impacts on its abundance (Amaya and Bonino 1981, Bonino and Soriguer 2009, Huertas-Herrera et al 2022. They feed on seedlings of various native shrubs and trees (e.g., Berberis and Nothofagus) and non-native herbs (e.g., Poa and Vicia), thus affecting their regeneration (Amaya and Bonino 1981, Bonino and Soriguer 2009, Huertas-Herrera et al 2022.…”

“…Rabbits in continental Magallanes and neighboring Tierra del Fuego Island consume plant biomass and generate important negative impacts on its abundance (Amaya and Bonino 1981, Bonino and Soriguer 2009, Huertas-Herrera et al 2022. They feed on seedlings of various native shrubs and trees (e.g., Berberis and Nothofagus) and non-native herbs (e.g., Poa and Vicia), thus affecting their regeneration (Amaya and Bonino 1981, Bonino and Soriguer 2009, Huertas-Herrera et al 2022. Plants that are not consumed by rabbits spread and generate changes in the botanical composition of the ecosystem (Bonino 2006, Bonino andSoriguer 2009).…”