Assessment of Detection Methods and Vegetation Associations for Introduced Finlayson's Squirrels (Callosciurus finlaysonii) in Italy

Exotic Pet Trade as a Cause of Biological Invasions: The Case of Tree Squirrels of the Genus Callosciurus

Simple Summary

The pet industry is a growing global multibillion dollar market. The increase of exotic and non-domesticated animal ownership has led to an increase in the number of non-native pets released that create invasive alien species (IAS) populations in the wild. IAS negatively impact the biodiversity, human health and countries’ economies. We use tree squirrels of the genus Callosciurus as a well-documented case study of pets that become IAS. We review the pathways and range of introduction and the challenge and legal importance of species identification. Next, we document how they negatively affect native plants and animals, their parasitic infections that can threat native wildlife and human health and their impact on human activities and productive systems. We discuss the diverse biological, social, political and economic reasons that make control/eradication of these charismatic species difficult in most countries. However, we also highlight the successful management of the IAS in two countries where the early detection and engagement of stakeholders were key to successful eradication. We conclude that efforts to educate and involve the broader public by actively engaging a diversity of stakeholders are more likely to build a consensus toward IAS management and should be a priority for each country.

Abstract

The trade of non-native pets, especially of non-domesticated and exotic animals, and their subsequent release and establishment of populations is one of the major pathways of introduction for invasive alien reptiles, amphibia, birds and mammals. Here, we use a group of arboreal mammals, tree squirrels of the genus Callosciurus, as a well-documented case study, reviewing the pathways of introduction, the current areas of non-native distribution, the rate of establishment success and the challenge and legal importance of species identification. We further illustrate the importance of early detection and effective monitoring methods and plans. Next, we document how they interfere with native species, their risk of acting as vectors for emerging infectious diseases and their potential role in maintaining parasitic infections that can affect human health. We conclude by reviewing the current management, or the lack of it, and highlight the diverse biological, social, political and economic reasons that make control/eradication of these charismatic species difficult or even impractical in most countries. However, reviewing the only two successful eradications of the IAS, we highlight the need to acknowledge the public opinion and the importance of communication, transparency and the engagement of a diversity of stakeholders to create a consensus about the actions to undertake.

Evaluation of Urban Environmental and Economic Coordination Based on Discrete Mathematical Model

The urban ecological environment is the material basis and condition for human beings to engage in social and economic activities and the supporting system for the formation and sustainable development of cities. With the acceleration of urbanization and industrialization, urban living environments and economic development have become the focus of people’s attention. This leads to the necessity of studying how to improve the quality of the urban living environment and promote the harmonious coexistence of population, natural environment, and social economy. Traditional methods focus on multiple regression models to evaluate the urban environmental and economic harmony, but this method does not consider the weight of each index, resulting in poor accuracy of the evaluation results. This paper proposes a discrete mathematical model to design the evaluation index and evaluation system of urban environmental and economic coordination. It calculates the weight of each index; carrying capacity of the urban environment, the value of each environmental factor, and the comprehensive value of the environment is determined. The static evaluation and dynamic evaluation are used to evaluate the coordination of the urban environmental economy. The experimental results show that the designed evaluation method of urban environmental economic coordination has high accuracy and effectively improves the reliability and evaluation time.

A framework for prioritising present and potentially invasive mammal species for a national list

The European Union (EU) has recently adopted a regulation on invasive alien species that foresees the possibility of developing lists of species of National Concern. We developed a prioritisation process for alien mammals already established in Italy, but not yet included in the EU list (n = 6 species) and a systematic horizon-scanning procedure to obtain ranked lists for those species that are already introduced worldwide or traded in Italy (n = 213). Experts were asked to score these species, by evaluating their likelihood of establishment and spread and the magnitude of their potential impacts on biodiversity, economy, human-health and society. The manageability of each species was also evaluated, both for the proritisation and the horizon-scanning processes. We produced five lists that ranked species according to their potential spread and impacts and their manageability. These will allow policy-makers to select outputs according to a balance between risk assessment and risk management, establishing priorities for alien species management at the national level.

Systematic Pathologic Findings Report of Callosciurus finlaysonii (Horsfield, 1823) (Rodentia, Sciuridae) Squirrels from Maratea area (South Italy) to Investigate Species-Specific Pathologies, Reliability of CO2 Euthanasia Method, and Possible Use as Environmental Sentinels

Simple Summary

Sciurus vulgaris has been considered by the International Union for Conservation of Nature (IUCN) due to the risk of extinction caused by the invasion of the invasive species (IAS) such as Callosciurus finlaysonii Horsfield, 1823. This species originated from Southeast Asia and it was introduced in Italy, in 1980. These animals could cause the extinction of the autochthonous counterpart and might also represent a concern, due to the progressive and unavoidable invasion of urban areas.

Abstract

The aim of the present study was to macroscopically and microscopically describe the main pathological findings occurring in this invasive species, in order to better understand the real risks for naïve animals and humans. The present study was conducted on Callosciurusfinlaysonii squirrels (n = 165), captured in the Maratea area and euthanatized with CO₂ according to a population control of invasive species of the Italian Agriculture Ministry project (ex CIPE project) and conferred to the Department of Veterinary Medicine of Bari (Italy). Macroscopic analysis demonstrated heart, lung, and liver congestion, probably due to the euthanasia method, and variable lesions of bowel, liver, and kidney. The microscopically examination showed the presence of lymphocytic infiltration in the lower layers of the bowel, suggesting enteritis. To the best of our knowledge, this is the first systemic report of gross and microscopical anatomopathological lesions in C.finlaysonii, in South Italy. The results could be useful to fill a gap of knowledge of this species in Italy.

Gimme shelter: The effect of rocks and moonlight on occupancy and activity pattern of an endangered rodent, the garden dormouse Eliomys quercinus

Information on spatial behaviour and temporal activity patterns is paramount for the conservation of animal species. This is particularly true for endangered taxa that are threatened by ongoing climatic and environmental changes. The garden dormouse Eliomys quercinus is a native European rodent (family Gliridae), whose populations are declining throughout the Continent. Notwithstanding this, neither International nor National laws explicitly require mandatory monitoring of populations. As a result, compelling information on the spatiotemporal behaviour of dormouse is lacking. We aimed to fill this gap by investigating occupancy patterns in relation to environmental features and activity rhythms in relation to moonlit nights in an Alpine population of dormouse within the Stelvio National Park, northern Italy. Data were collected between May and October 2015. Twenty camera-traps were deployed in a 500 ha coniferous forest, using a random tessellation approach; camera trap data were analyzed with occupancy models and kernel smoothers. Camera-traps provided a reliable assessment of the presence of the garden dormouse, with only 1 % of false absence and a high detection probability (68 %). The occurrence of the garden dormouse was positively influenced by the percentage of rock coverage on the ground. The species showed a strictly nocturnal behaviour, with an activity peak before midnight, negatively related to moonlit nights. The use of rocky areas for nesting, shelter site and thigmotactic movements and moonlight avoidance may represent adaptations of the garden dormouse to avoid predation risk. Our results shed some light on the habitat requirement of a poorly known, near-threatened species, and provide baseline information for future monitoring and conservation activities.

Early and efficient detection of an endangered flying squirrel by arboreal camera trapping

Endangered species management is typically informed by an ecological knowledge of a species. Currently, little is known about the distribution and ecology of the Japanese flying squirrel (Pteromys momonga). To provide an effective rapid survey technique for flying squirrels, we used camera trap surveys and determined what methodology (i.e. camera placement, survey length) was most efficient. We placed 154 cameras in trees for 30 days. We detected flying squirrels at 12% of the camera points. The average suitable distance between camera and targeted tree (DCT) was 130 cm (SE: 15.4, range: 90–220). Moreover, flying squirrels were frequently detected on the trunks of taller trees. We found camera trap surveys were an efficient technique for detecting flying squirrels. Approximately 11% of camera points detected flying squirrels within one survey night. Initial detection of flying squirrels at a site occurred within 10 days at 58% of the points. To efficiently detect flying squirrels, we suggest that it is better to aim the camera towards taller trees at a suitable DCT and to conduct surveys for a minimum of 10 days at each site.

A cross-sectional survey to evaluate the pet squirrel population and ownership profiles

While the presence of squirrels in households is growing, little data is published on their status in captivity. A web-based questionnaire for owners was devised eliciting information about them, their squirrels and their squirrels' husbandry and health. One hundred owners answered the survey, with most respondents being located in Europe (n = 81). Only data from these respondents were analysed. Twenty-five percents of the owners housed an invasive non-native species of European Union concern (S. carolinensis and T. sibiricus), some of which were younger than three years of age and all but one were sexually intact. This is of particular concern, as the acquisition of these invasive species is illegal since 2015 (European Union Regulation 1143/2014), due to the severe threats they pose to biodiversity. Moreover, escapes derived from improper keeping of intact specimens may augment feral populations or establish new colonies. Among 81 cases, only 5% were neutered, mostly for health reasons. Sixty-three percents of the squirrels had health problems, particularly dermatologic (52%) and intestinal disorders (34%). Most owners reported to visit the veterinarian only if their pet was ill rather than for preventive care. This is the first survey on pet squirrel ownership reported to date. Information that emerges from this study will be useful in implementing rational veterinary strategies for managing pet squirrels properly and, in parallel, meeting the challenges arising from private keeping of alien species.

Spatial behaviour of an overlooked alien squirrel: The case of Siberian chipmunks Eutamias sibiricus

Alien species of concern within the European Union have been recently listed and their populations need to be monitored, to plan addressed eradication or control programs. Therefore, the assessment of their presence should be rapidly carried out, particularly for elusive species or for those living at low densities. The Siberian chipmunk Eutamias sibiricus is a ground-dwelling squirrel, naturally distributed in northern and eastern Asia. Many introduced populations occur in Europe and Italy too. This species has been listed within the invasive species concern within the European Union and, thus, monitoring is mandatory to manage its potential range expansion. We carried out a hair-tube survey on 31 wood patches in northern and central Italy, where reproductive populations of Siberian chipmunk have been recorded. Hair tubes provided reliable data in assessing the presence of the Siberian chipmunk, with only 1% pseudo-absence and a high detection probability. The occurrence of Siberian chipmunk was positively influenced by study site and by the distance from release site, confirming low dispersal abilities by this species. Dense understorey also affected the presence of chipmunks, preventing them to search for food on the ground and to dig burrows.