The roles of leporid species that have been translocated: a review of their ecosystem effects as native and exotic species

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

The European rabbit has invaded numerous ecosystems worldwide, but rarely steppes. Since its various introduction attempts into the ecosystems of the Magallanes/Fuegian region, the rabbit has become a key player, interacting with species at different trophic levels and generating impacts on ecosystems. To better understand the role of the rabbit in steppe and scrub ecosystems, we characterised the food web in the Magallanes/Fuegian region to understand the identity of their interacting species, the mechanisms and complexities of their interactions to demonstrate that rabbit management may become more complex than just controlling a single species. Based on a bibliographic review and wildlife specialists' opinions, we built the Magellanic/Fuegian food web, evaluated their topological properties and performed a rabbit extinction simulation to assess the possible short-term ecological mechanisms operating in the community. We found that the network had 206 nodes (64% native, 13% exotic, and 22% mixed) and 535 links among nodes. The European rabbit was the most connected node of the food web, had the second largest dietary breadth, and ranked as the seventh prey item with more predators. A rabbit extinction simulation shows a possible release of herbivory pressure on plants, including that on several native plants (e.g., Gunnera tinctoria, Pratia repens, Gavilea lutea, Tetroncium magellanicus), and a possible release of competition for some herbivores that share resources with the rabbit (e.g., Ovis aries, Lama guanicoe, Bos taurus). Although rabbit predators have a broad and generalist diet, some such as the native Galicitis cuja, could face a 20% reduction in their trophic width and could intensify predation on alternative prey. These results show that the European rabbit is strongly embedded in the Magellanic/Fuegian ecosystem and linked to several native species. Therefore, rabbit management should consider ecosystem approaches accompanied by monitoring programs on native fauna and experimental pilot studies on native flora to conserve the Chilean Patagonia community.

European Rabbit Invasion in a Semi-Arid Ecosystem of Chile: How Relevant Is Its Role in Food Webs?

The European rabbit (Oryctolagus cuniculus) is one of the main invasive species in Chile, where it became naturalized ca. 150 years ago. Their high reproductive capacity, lack of specialist predators, and great adaptability favored the settlement of rabbits in diverse mainland and island ecosystems of the country. Recently, rabbits have become central players in semi-arid ecosystems, such as those represented in Las Chinchillas National Reserve in north-central Chile. We undertook to analyze the place and role of rabbits in the food web of that Reserve, based on a bibliographic review and long-term annual data gathered from 1987 until 2022 (36 years). Results showed that the network comprised 77 species, where 69% were primary producers (plants), 18% were mid-level consumers (herbivores), and 13% were top-level consumers (predators). The most connected species in the food web was the rabbit, which positively or negatively affected the species interacting with it. Predators such as Galictis cuja, Geranoaetus polyosoma, Leopardus colocolo, and Puma concolor, and the scavenger Vultur gryphus, could be negatively affected by an eventual decrease (natural or human-caused) in the rabbit population of the Reserve. To the contrary, primary producers such as Oxalis perdicaria, Plantago hispidula, Schizanthus parvulus, Senna cumminggi, and Tropaeolum azureum could be positively affected by an increase in their biomass in response to a decrease in rabbits, favoring native rodents. We consider that analyzing the rabbit-centered food web and its impacts on native interacting species allows a better understanding of the relevance of invasive species in the local community, providing conceptual tools for rabbit management.

An assessment of the environmental and socio-economic impacts of alien rabbits and hares

Directly comparable data on the environmental and socio-economic impacts of alien species informs the effective prioritisation of their management. We used two frameworks, the Environmental Impact Classification for Alien Taxa (EICAT) and Socio-Economic Impact Classification for Alien Taxa (SEICAT), to create a unified dataset on the severity and type of impacts caused by alien leporids (rabbits and hares). Literature was reviewed to collate impact data, which was categorised following EICAT and SEICAT guidelines. We aimed to use these data to identify: (1) alien leporid species with severe impacts, (2) their impact mechanisms, (3) the native species and local communities vulnerable to impacts and (4) knowledge gaps. Native species from a range of taxonomic groups were affected by environmental impacts which tended to be more damaging than socio-economic impacts. Indirect environmental impacts were particularly damaging and underreported. No impact data were found for several alien leporid species.

Spatiotemporal Overlap between the European Brown Hare and Its Potential Predators and Competitors

Analysis of spatiotemporal partitioning is pivotal to shed light on interspecific coexistence. Most research effort has involved large-sized carnivores and their prey, whereas little attention has been devoted to lagomorphs. We assessed spatiotemporal overlap among the European brown hare Lepus europaeus and its potential competitors and predators through camera-trapping in an area in Central Italy. We estimated the interspecific patterns of the spatiotemporal activity rhythms of brown hares, its potential predators (the red fox Vulpes vulpes, the pine marten Martes martes, the domestic cat Felis catus, and the domestic dog Canis familiaris), and a competitor, the roe deer Capreolus capreolus. Brown hare activity was studied in natural conditions as well as in a fenced area that excluded terrestrial predators and competitors. Free-ranging hares developed a more nocturnal behavior to avoid diurnal predators (i.e., domestic carnivores and martens). Although high temporal overlap was observed between free-ranging brown hares and both red foxes (82%) and roe deer (81%), hares avoided fox by being more active on darkest nights, as well as avoided roe deer through spatial partitioning. We suggest that hares may adapt their spatiotemporal behavior to avoid potential predators and competitors.

Mammals of Paso Centurión, an area with relicts of Atlantic Forest in Uruguay

Paso Centurión is one of the most diverse areas of Uruguay. It is legally protected at local and national level, however, there are different interests competing for its land use and management. With the aim to document the biodiversity of the area together with the local people, the NGO JULANA has been conducting a participatory monitoring process with camera traps since 2013. Here, we present a list of 23 medium and large-size mammal species documented in the area and a standardised dataset of occurrence records. Top observations include the last Chrysocyon brachyurus seen in Uruguay, the first record of Herpailurus yagouaroundi in the country and the second report of Leopardus munoai in the area. We also highlight the frequent observation of numerous rare species such as Tamandua tetradactyla, Leopardus wiedii, Cabassous tatouay, Coendou spinosus and Cuniculus paca. Although the cameras were located within only a few metres of the houses of the local people, some of the rarest and most elusive species in the country were reported. This suggests a possible coexistence between people – their socio-economic practices – and nature in the area. Our work underlines the importance of the recent inclusion of Paso Centurión and Sierra de Ríos to the National System of Protected Areas under the proposed category of ‘Protected Landscape’. Collectively, in a context of global change and lack of biodiversity data on species distribution, we emphasise the value of these records for the knowledge of mammals in Uruguay and the need to extend and continue monitoring this area.

Environmental drivers of parasite load and species richness in introduced parakeets in an urban landscape

Introduced species represent a threat to native wildlife worldwide, due to predation, competition, and disease transmission. Concurrent introduction of parasites may also add a new dimension of competition, i.e. parasite-mediated competition, through spillover and spillback dynamics. Urban areas are major hotspots of introduced species, but little is known about the effects of urban habitat structure on the parasite load and diversity of introduced species. Here, we investigated such environmental effects on the ectoparasite load, richness, and occurrence of spillback in two widespread invasive parakeets, Psittacula krameri and Myiopsitta monachus, in the metropolitan area of Rome, central Italy. We tested 231 parakeets and found that in both species parasite load was positively influenced by host abundance at local scale, while environmental features such as the amount of natural or urban habitats, as well as richness of native birds, influenced parasite occurrence, load, and richness differently in the two host species. Therefore, we highlight the importance of host population density and habitat composition in shaping the role of introduced parakeets in the spread of both native and introduced parasites, recommending the monitoring of urban populations of birds and their parasites to assess and manage the potential occurrence of parasite-mediated competition dynamics as well as potential spread of vector-borne diseases.