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Wauters LA, Lurz PWW, Santicchia F, Romeo C, Ferrari N, Martinoli A, Gurnell J. Interactions between native and invasive species: A systematic review of the red squirrel-gray squirrel paradigm. Front Ecol Evol 2023. [DOI: 10.3389/fevo.2023.1083008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/03/2023] Open
Abstract
The eastern gray squirrel (Sciurus carolinensis) has been labeled as one of the 100 worst invasive alien species by the IUCN. In Europe, the species has been introduced to Britain, Ireland and Italy, and its subsequent spread has resulted in wide-scale extinction of native Eurasian red squirrels (Sciurus vulgaris) from the areas colonized by the gray squirrel. This replacement of a native by an alien competitor is one of the best documented cases of the devastating effects of biological invasions on native fauna. To understand how this replacement occurs, we present a systematic review of the literature on competition and interactions between red and gray squirrels. We describe the patterns of red and gray squirrel distribution in those parts of Europe where gray squirrels occur and summarize the evidence on the different processes and mechanisms determining the outcome of competition between the native and alien species including the influence of predators and pathogens. Some of the drivers behind the demise of the red squirrel have been intensively studied and documented in the past 30 years, but recent field studies and mathematical models revealed that the mechanisms underlying the red-gray paradigm are more complex than previously thought and affected by landscape-level processes. Therefore, we consider habitat type and multi-species interactions, including host-parasite and predator-prey relationships, to determine the outcome of the interaction between the two species and to better address gray squirrel control efforts.
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Zdun M, Ruszkowski JJ, Hetman M, Felsmann MZ. Head arteries of the red squirrel (Sciurus vulgaris). Vet Res Commun 2022; 47:723-729. [DOI: 10.1007/s11259-022-10033-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Accepted: 10/25/2022] [Indexed: 11/12/2022]
Abstract
AbstractThe red squirrel (Sciurus vulgaris) is a medium-sized rodent protected in most of Europe. The present study aimed to investigate and describe the arterial vascularization of the head of the adult red squirrel. In the study, 48 specimens of adult red squirrels were used. The first preparation method used in the study was corrosion casting using a stained solution of the chemo-setting acrylic material injected into bilateral common carotid arteries resulting in corrosion castings of the vessels on a bone scaffold. The second method was injecting liquid-stained latex into both common carotid arteries. It resulted in a stained arterial vessel on fixed soft tissue preparations. The main vessels providing blood to the head were paired with common carotid arteries that divide into external and internal carotid arteries. The internal carotid artery passes into the stapedial artery. After giving its branches, the stapedial artery exits the cranial cavity through the sphenofrontal foramen and enters the orbit. The suborbital and the mandibular regions were supplied by the maxillary artery, linguofacial trunk, and their branches. Description of the detailed anatomy of the head arteries in red squirrels may contribute to establishing diagnostic and treatment protocols for wildlife rehabilitation centers, which may be crucial since red squirrels are endangered by the spreading of invasive Eastern gray squirrels (Sciurus carolinensis) in Europe. It may also contribute to veterinary care for other members of the Sciuridae family kept as pets.
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Cruciani D, Crotti S, Paoloni D, La Morgia V, Felici A, Papa P, Cosseddu GM, Moscati L, Gobbi P. Health Status of the Eastern Grey Squirrel ( Sciurus carolinensis) Population in Umbria: Results of the LIFE Project 'U-SAVEREDS'. Animals (Basel) 2022; 12:ani12202741. [PMID: 36290127 PMCID: PMC9597752 DOI: 10.3390/ani12202741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Revised: 09/09/2022] [Accepted: 10/11/2022] [Indexed: 11/07/2022] Open
Abstract
Simple Summary Invasive alien species are non-native species introduced deliberately or unintentionally beyond their past or present natural distribution, and their introduction and spread threatens local biological diversity. The Eastern grey squirrel is native to North America and was introduced to the British Islands, Italy, and South Africa. Around the year 2000, a new population of grey squirrels was recorded in Perugia, central Italy, where the species populated an area of approximately 50 km2, both in woodland and urban areas. The Eastern grey squirrel represents a huge threat to the conservation of the native Eurasian red squirrel when the two species coexist. Moreover, given their confident behaviour with humans, the non-native squirrels can negatively impact public health. The U-SAVEREDS Project was set up for Eurasian red squirrel conservation in Umbria through the eradication of the alien species and it also provided information on the health status of the Eastern grey squirrel to identify any infectious agents. The recovery of zoonotic pathogens allowed to assess the Eastern grey squirrel’s impact on human and domestic and wild animals’ health, provide helpful feedback for the management and eradication procedures, and raise public awareness through environmental education. Abstract The introduction of the Eastern grey squirrel (Sciurus carolinensis) in Europe is one of the best-known cases of invasive alien species (IAS) colonisation, that poses a severe risk to the conservation of biodiversity. In 2003, it was released in a private wildlife park near the city of Perugia (Italy), where it is replacing the native Eurasian red squirrel (Sciurus vulgaris). The LIFE13 BIO/IT/000204 Project (U-SAVEREDS) was set up for the Sciurus vulgaris conservation in Umbria through an eradication campaign of grey squirrels. One hundred and fifty-four animals were analysed for bacteriological, mycological, virological, and serological investigations (C4 action). Sanitary screening showed that Sciurus carolinensis is a dermatophyte carrier, and therefore, it could cause public health issues for humans, considering its confident behaviour. Moreover, it has been marginally responsible for the spreading of Candida albicans, Coxiella burnetii, and Borrelia lusitaniae. Health status evaluation conducted on the Sciurus carolinensis population indicated that it is necessary to raise awareness of its impacts on biodiversity and human health. Moreover, the health status and behaviours of the IAS must be considered when control or eradication campaigns are planned.
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Affiliation(s)
- Deborah Cruciani
- Istituto Zooprofilattico Sperimentale dell’Umbria e delle Marche “Togo Rosati” (IZSUM), Via G. Salvemini 1, 06126 Perugia, Italy
- Correspondence:
| | - Silvia Crotti
- Istituto Zooprofilattico Sperimentale dell’Umbria e delle Marche “Togo Rosati” (IZSUM), Via G. Salvemini 1, 06126 Perugia, Italy
| | | | - Valentina La Morgia
- Istituto Superiore per la Protezione e la Ricerca Ambientale (ISPRA), Via Vitaliano Brancati 48, 00144 Roma, Italy
| | - Andrea Felici
- Istituto Zooprofilattico Sperimentale dell’Umbria e delle Marche “Togo Rosati” (IZSUM), Via G. Salvemini 1, 06126 Perugia, Italy
| | - Paola Papa
- Istituto Zooprofilattico Sperimentale dell’Umbria e delle Marche “Togo Rosati” (IZSUM), Via G. Salvemini 1, 06126 Perugia, Italy
| | - Gian Mario Cosseddu
- Istituto Zooprofilattico Sperimentale del Lazio e della Toscana “M. Aleandri” (IZSLT), Via Appia Nuova 1411, 00178 Roma, Italy
- Istituto Zooprofilattico Sperimentale Abruzzo e Molise “G. Caporale” (IZSAM), Campo Boario, 64100 Teramo, Italy
| | - Livia Moscati
- Istituto Zooprofilattico Sperimentale dell’Umbria e delle Marche “Togo Rosati” (IZSUM), Via G. Salvemini 1, 06126 Perugia, Italy
| | - Paola Gobbi
- Istituto Zooprofilattico Sperimentale dell’Umbria e delle Marche “Togo Rosati” (IZSUM), Via G. Salvemini 1, 06126 Perugia, Italy
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Yu L, Zhao S, Meng F, Shi Y, Xu C. Dispersal and mating patterns determine the fate of naturally dispersed populations: evidence from Bombina orientalis. BMC Ecol Evol 2021; 21:111. [PMID: 34098874 PMCID: PMC8182911 DOI: 10.1186/s12862-021-01844-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 06/02/2021] [Indexed: 12/05/2022] Open
Abstract
Background In contrast to the explosive increase of a population following biological invasion, natural dispersal, i.e., when a population disperses from its original range into a new range, is a passive process that is affected by resources, the environment, and other factors. Natural dispersal is also negatively impacted by genetic drift and the founder effect. Although the fates of naturally dispersed populations are unknown, they can adapt evolutionarily over time to the new environment. Can naturally dispersed populations evolve beneficial adaptive strategies to offset these negative effects to maintain their population in a stable state? Results The current study addressed this question by focusing on the toad Bombina orientalis, the population of which underwent natural dispersal following the Last Glacial Maximum in Northeast Asia. Population genetic approaches were used to determine the genetic structure, dispersal pattern, and mating system of the population of B. orientalis in northeast China (Northern population). The results showed that this northern population of B. orientalis is a typical naturally dispersed population, in which the stable genetic structure and high level of genetic diversity of the population have been maintained through the long-distance biased dispersal behavior of males and the pattern of promiscuity within the population. Conclusions Our findings suggest that naturally dispersed populations can evolve effective adaptive strategies to maintain a stable population. Different species may have different strategies. The relevance of these maintenance mechanisms for naturally dispersed populations provide a new perspective for further understanding the processes of speciation and evolution. Supplementary Information The online version contains supplementary material available at 10.1186/s12862-021-01844-3.
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Affiliation(s)
- Liqun Yu
- College of Life Science, Northeast Agricultural University, No. 600 Changjiang Road Xiangfang District, Harbin, 150030, China
| | - Shuai Zhao
- College of Life Science, Northeast Agricultural University, No. 600 Changjiang Road Xiangfang District, Harbin, 150030, China
| | - Fanbing Meng
- College of Life Science, Northeast Agricultural University, No. 600 Changjiang Road Xiangfang District, Harbin, 150030, China
| | - Yanshuang Shi
- College of Life Science, Northeast Agricultural University, No. 600 Changjiang Road Xiangfang District, Harbin, 150030, China
| | - Chunzhu Xu
- College of Life Science, Northeast Agricultural University, No. 600 Changjiang Road Xiangfang District, Harbin, 150030, China.
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Slade A, White A, Kortland K, Lurz PWW. Natural strongholds for red squirrel conservation in Scotland. NATURE CONSERVATION 2021. [DOI: 10.3897/natureconservation.43.62864] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The Eurasian Red Squirrel (Sciurus vulgaris) is under threat from the invasive North American eastern Grey Squirrel (Sciurus carolinensis) with 80% of the remaining red squirrel populations in the British Isles found in Scotland. In this study we develop a spatially explicit mathematical model of the red and grey squirrel system and use it to assess the population viability of red squirrels across Scotland. In particular, we aim to identify existing forests – natural strongholds for red squirrels – that can successfully support red squirrels under UK Forestry Standard management and protect them from potential disease-mediated competition from grey squirrels. Our model results indicate that if current levels of grey squirrel control, which restrict or reduce the distribution of grey squirrels, are continued then there will be large expanses of forests in northern Scotland that support viable red squirrel populations. Model results that represent (hypothetical) scenarios where grey squirrel control no longer occurred indicated that grey squirrel range expansion and the process of red squirrel replacement would be slow. Model results for an assumed worst-case scenario where grey squirrels have expanded to all regions in Scotland identified forest regions – denoted natural strongholds – that could currently support red squirrels under UK Forestry Standard management practice. The results will be used to inform forest management policy and support a strategic review of red squirrel management by land management agencies and other stakeholders.
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Seasonal Expression of NGF and Its Cognate Receptors in the Ovaries of Grey Squirrels ( Sciurus carolinensis). Animals (Basel) 2020; 10:ani10091558. [PMID: 32887345 PMCID: PMC7552179 DOI: 10.3390/ani10091558] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 08/27/2020] [Accepted: 08/28/2020] [Indexed: 12/05/2022] Open
Abstract
Simple Summary Invasive alien species pose a significant threat to biodiversity, as once they have adapted to their new environment, they cause the reduction and even extinction of native species. In this framework, the American grey squirrel (Sciurus carolinensis) poses a serious threat to the European red species squirrel (Sciurus vulgaris), especially in the Umbria region of Italy. In fact, an invasive grey squirrel population has adapted well to the Umbrian territory, showing high reproductive success. In addition to its role in the development of the vertebrate nervous system, nerve growth factor (NGF) has recently been found to play an important role in reproduction. In order to investigate the reproductive physiology of female grey squirrels, the ovarian presence, distribution, and gene expression of NGF and its cognate receptors were evaluated during both breeding and nonbreeding seasons. The presence and gene expression of this system at the ovarian level, mainly during the breeding season, confirm the possible involvement of NGF and its receptors in the gonadal activity of this invasive grey squirrel population. Abstract The grey squirrel is an invasive alien species that seriously threatens the conservation of the native red squirrel species. With the aim of characterizing the reproductive physiology of this species due to its great reproductive success, the function of the ovarian nerve growth factor (NGF) system was analyzed in a grey squirrel population living in central Italy. During the breeding and nonbreeding seasons, the ovarian presence, distribution, and gene expression of NGF, neurotrophic tyrosine kinase receptor 1 (NTRK1), and nerve growth factor receptor (NGFR), as well as NGF plasma concentrations, were evaluated in female grey squirrels. NGF was found in the luteal cells and in the thecal and granulosa cells of follicles, while NTRK1 and NGFR were only observed in follicular thecal and granulosa cells. NGF and NGFR transcripts were almost two-fold greater during the breeding season, while no seasonal differences were observed in NTRK1 gene expression. During the breeding season, NGFR was more expressed than NTRK1. Moreover, no changes were observed in NGF plasma levels during the reproductive cycle. The NGF system seems to be involved in regulating the ovarian cycle mainly via local modulation of NGF/NGFR, thus playing a role in the reproductive physiology of this grey squirrel population.
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Reproductive Traits of an Invasive Alien Population of Grey Squirrel ( Sciurus carolinensis) in Central Italy. Animals (Basel) 2020; 10:ani10040738. [PMID: 32344507 PMCID: PMC7223364 DOI: 10.3390/ani10040738] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 04/13/2020] [Accepted: 04/19/2020] [Indexed: 01/18/2023] Open
Abstract
The reproductive cycle of an invasive alien Italian grey squirrel population was studied to understand its adaptation and limit its spread, in order to conserve the autochthonous red squirrel. Female and male genital traits were evaluated throughout the reproductive cycle, including the ovary, uterus, testicle, epididymis, seminiferous tubule morphometry, and germinative epithelium histology. Moreover, individual female fecundity was determined by counting uterine scars. Ovary width and uterus weight, length, and width reached their highest values in the luteal and pregnancy phases. On conducting a histological evaluation of the testicular germinal epithelium, four morphotypes related to the different reproductive phases of the male squirrels were identified: immature, pubertal, spermatogenesis, and regressive. Testicle and epididymis weights and seminiferous tubule diameters reached their largest values during spermatogenesis. Uterine scar analysis showed that 69% of the females had given birth to one or two litters, while 31% had no uterine scars. Litters were larger in the first breeding period than in the second; annual fecundity was 4.52 ± 1.88 uterine scars/female. Umbrian grey squirrels have adapted to their non-native range, showing two annual mating periods at times similar to those in their native range, and high reproductive success.
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Romeo C, McInnes CJ, Dale TD, Shuttleworth C, Bertolino S, Wauters LA, Ferrari N. Disease, invasions and conservation: no evidence of squirrelpox virus in grey squirrels introduced to Italy. Anim Conserv 2018. [DOI: 10.1111/acv.12433] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- C. Romeo
- Department of Veterinary Medicine Università degli Studi di Milano Milan Italy
| | | | - T. D. Dale
- Institute of Integrative Biology University of Liverpool Liverpool UK
| | - C. Shuttleworth
- School of Environment, Natural Resources and Geography Bangor University Bangor Gwynedd UK
| | - S. Bertolino
- Department of Life Sciences and Systems Biology Università degli Studi di Torino Torino Italy
| | - L. A. Wauters
- Department of Theoretical and Applied Sciences Università degli Studi dell'Insubria Varese Italy
| | - N. Ferrari
- Department of Veterinary Medicine Università degli Studi di Milano Milan Italy
- Centro di Ricerca Coordinata Epidemiologia e Sorveglianza Molecolare delle Infezioni Università degli Studi di Milano Milan Italy
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Di Giuseppe AM, Russo L, Russo R, Ragucci S, Caso JV, Isernia C, Chambery A, Di Maro A. Molecular characterization of myoglobin from Sciurus vulgaris meridionalis : Primary structure, kinetics and spectroscopic studies. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2017; 1865:499-509. [DOI: 10.1016/j.bbapap.2017.02.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Revised: 01/18/2017] [Accepted: 02/14/2017] [Indexed: 10/20/2022]
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La Morgia V, Paoloni D, Genovesi P. Eradicating the grey squirrel Sciurus carolinensis from urban areas: an innovative decision-making approach based on lessons learnt in Italy. PEST MANAGEMENT SCIENCE 2017; 73:354-363. [PMID: 27367228 DOI: 10.1002/ps.4352] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Revised: 06/24/2016] [Accepted: 06/29/2016] [Indexed: 06/06/2023]
Abstract
BACKGROUND Eradication of invasive alien species supports the recovery of native biodiversity. A new European Union Regulation introduces obligations to eradicate the most harmful invasive species. However, eradications of charismatic mammals may encounter strong opposition. Considering the case study of the eastern grey squirrel (Sciurus carolinensis Gmelin, 1788) in central Italy, we developed a structured decision-making technique based on a Bayesian decision network model and explicitly considering the plurality of environmental values of invasive species management to reduce potential social conflicts. RESULTS The model identified priority areas for management activities. These areas corresponded to the core of the grey squirrel range, but they also included peripheral zones, where rapid eradication is fundamental to prevent the spread of squirrels. However, when the model was expanded to integrate the attitude of citizens towards the project, the intervention strategy slightly changed. In some areas, the citizens' support was limited, and this resulted in a reduced overall utility of intervention. CONCLUSION The suggested approach extends the scientific basis for management decisions, evaluated in terms of technical efficiency, feasibility and social impact. Here, the Bayesian decision network model analysed the potential technical and social consequences of management actions, and it responded to the need for transparency in the decision-making process, but it can easily be extended to consider further issues that are common in many mammal eradication programmes. Owing to its flexibility and comprehensiveness, it provides an innovative example of how to plan rapid eradication or control activities, as required by the new EU Regulation. © 2016 Society of Chemical Industry.
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Affiliation(s)
| | | | - Piero Genovesi
- Institute for Environmental Protection and Research - ISPRA, Rome, Italy
- IUCN SSC Invasive Species Specialist Group
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Dozières A, Pisanu B, Kamenova S, Bastelica F, Gerriet O, Chapuis JL. Range expansion of Pallas's squirrel (Callosciurus erythraeus) introduced in southern France: Habitat suitability and space use. Mamm Biol 2015. [DOI: 10.1016/j.mambio.2015.08.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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