In this study, a dataset on world-wide squirrel introductions has been used to locate the relative pathways and to determine the factors correlated with species establishment. The world. The analysis ...includes a chronological table of introductions, a biogeographical analysis and an assessment of the likelihood of establishment according to species, propagule pressure, area of origin and characteristics of the recipient area. The main vector of such introductions was the intentional importation of live animals. Introductions increased in developed countries and proportionately to the volume of imported mammals. Moreover, areas characterized by higher numbers of native squirrels were more invaded. Squirrels were often introduced deliberately and only to a smaller extent escaped from captivity. The likelihood of their establishment increased proportionately to the number of animals released and decreased proportionately to the increase of the latitudinal distance between the recipient area and the native range of the species. The likelihood that the release of one pair of either Sciurus or Callosciurus species would establish a new population was higher than 50%. Squirrels proved to be successful invaders and their importation should be restricted so as to prevent further introductions.
Ensuring the persistence of biodiversity and ecosystem services represents a global challenge that need to be addressed with high urgency. Global priority areas can only be identified by means of an ...integrated prioritization approach that would not only preserve species numbers and ecosystem services, but also the evolutionary and functional components of diversity. In this study we combine global datasets on the distribution of mammals and birds with species traits and phylogenetic data and we identify conservation priorities for taxonomic, functional and phylogenetic diversity, as well as for three ecosystem services, including potential for carbon sequestration, pollination potential and groundwater recharge. We show that, when priority areas are identified based only on individual, e.g. functional diversity, or any combination of the three biodiversity components, these areas do not allow a sufficient protection of the three ecosystem services. However, an integrated approach whereby prioritization is based on all biodiversity components and ecosystem services would allow to identify areas that maximize protection of all ecosystem services with a minimal loss in biodiversity coverage. Our results highlight the need for an integrated conservation planning framework in order to optimally allocate resources and achieve the long-term preservation of the multiple dimensions of biodiversity and ecosystems services.
In this work a mathematical model is built in order to validate on theoretical grounds field study results on a three-species system made of two prey, of which one is native and another one invasive, ...together with a native predator. Specifically, our results mathematically describe the negative effect on the native European hare after the introduction of the invasive Eastern cottontail, mediated by an increased predation rate by foxes. Two nonexclusive assumptions can be made: an increase in cottontail abundance would lead to a larger fox population, magnifying their predatory impact (“hyperpredation”) on hares; alternatively, cottontails attract foxes in patches where they live, which are also important resting sites for hares and consequently the increased presence of foxes results in a higher predation rates on hares. The model results support hyperpredation of increasing fox populations on native hares.
The introduction of the eastern grey squirrel (native to America) in Europe is causing a dramatic decline in the range of the native European red squirrel, due to competition. Grey squirrels compete ...with the native species mainly for food; furthermore, they can maintain and spread a poxvirus, which causes a lethal disease in red squirrels in Britain. According to some modelling scenarios, grey squirrels will spread from Italy to France and Switzerland in the next 20–30 years, and to a large part of Eurasia in the long term. This would represent a serious threat for the survival of the red squirrel throughout its range. This case study of biological invasion suggests that the risks posed by the introduced species may be minimized with a reduction in animal trade between countries and using a procedure of risk-assessment for every imported species.
The yellow-legged hornet
Vespa velutina
Lepeletier 1836, accidentally introduced into France in 2004, is rapidly colonizing other European countries. In Italy the species is spreading throughout the ...northwest part of the country. Setting up management plans for controlling invasive alien species requires an understanding of the spread modalities and distribution range of the species, information currently not available for the yellow-legged hornet in Italy. The aims of this work are to reconstruct the spread of the yellow-legged hornet from its first arrival in the country, evaluating its distribution range and spread modalities. The area occupied by the species increased from 205 km
2
in 2013 to 930 km
2
in 2015. In 2015 the frontline of the species was at 55 km along the coast from the French border, with a linear spread of 18.3 ± 3.3 km/year. A human-mediated dispersion could be recognized in different occasions. A cluster analysis of the range allowed the identification of 17 core areas used by the species, with a mean nest density of 2.9–3.5 nests/km
2
. These details are fundamental to improve control plans and to establish an early warning and rapid response system for the yellow-legged hornet in Italy and, therefore, setup an effective management plan for the species.
Eradication of invasive alien species is a form of pest control linked to biodiversity conservation, which usually involves animal killing. Squirrels are prominent among invasive alien species in ...Italy, with four species introduced. Three of them are included within the list of alien species of European concern, and their eradication and control is recommended. However, their local control is not an easy task, being often hindered by the general public. We propose a socio-ecological approach to evaluate the feasibility of eradicating Siberian chipmunks
Eutamias sibiricus
populations in Italy. We performed a structured questionnaire to assess the social perception of invasive Siberian chipmunks in urban parks, and to identify groups of visitors who might oppose eradication. We also carried out geographic profiling to test for the spatial expansion of chipmunk populations. Overall, park visitors regarded chipmunks positively and appreciated to see them, but human-chipmunk interactions were still rare. We did not identify any group of visitors with a strong attachment to chipmunks, who might oppose future control programs. Geographic profiling showed that chipmunks in Valeggio sul Mincio are starting to expand outside of their introduction site. Data from questionnaires show that chipmunks eradication, coupled with adequate communication initiatives, might be feasible. Moreover, geographic profiling indicates that time for a rapid removal is running out. Socio-ecological approaches, combining the analysis of structured questionnaires administered to stakeholders and statistical modeling of pest observations, could be a valuable tool to decide the feasibility and the urgency of invasive alien species control.
Animal space use is affected by spatio-temporal variation in food availability and/or population density and varies among individuals. This inter-individual variation in spacing behaviour can be ...further influenced by sex, body condition, social dominance, and by the animal’s personality. We used capture-mark-recapture and radio-tracking to examine the relationship between space use and personality in Eurasian red squirrels (
Sciurus vulgaris
) in three conifer forests in the Italian Alps. We further explored to what extent this was influenced by changes in food abundance and/or population density. Measures of an individual’s trappability and trap diversity had high repeatability and were used in a Principal Component Analysis to obtain a single personality score representing a boldness-exploration tendency. Males increased home-range size with low food abundance and low female density, independent of their personality. However, bolder males used larger core-areas that overlapped less with other males than shy ones, suggesting different resource (food, partners) utilization strategies among personality types. For females, space use-personality relationships varied with food abundance, and bolder females used larger home ranges than shy ones at low female density, but the trend was opposite at high female density. Females’ intrasexual core-area overlap was negatively related to body mass, with no effect of personality. We conclude that relationships between personality traits and space use in free-ranging squirrels varied with sex, and were further influenced by spatio-temporal fluctuations in food availability. Moreover, different personality types (bold-explorative vs. shy) seemed to adopt different space-use strategies to increase access to food and/or partners.
PDF
