Assessment of Detection Methods and Vegetation Associations for Introduced Finlayson’s Squirrels (Callosciurus finlaysonii) in Italy
- 55 Downloads
Managing biological invasions requires rapid, cost-effective assessments of introduced species’ occurrence, and a good understanding of the species’ vegetation associations. This is particularly true for species that are elusive or may spread rapidly. Finlayson’s squirrel (Callosciurus finlaysonii) is native to Thailand and southeastern Asia, and two introduced populations occur in peninsular Italy. One of the two introduced populations is rapidly expanding, but neither effective monitoring protocols nor reliable information on vegetation associations are available. To fill this gap, we conducted visual surveys and hair tube sampling in a periurban landscape of southern Italy to compare the effectiveness of these two methods in assessing presence of Finlayson’s squirrel. We also determined the species’ association with vegetation types at detection locations and nesting sites. Both visual and hair tube sampling effectively assessed the species’ presence, but hair tubes resulted in fewer false absences. Moreover, when we controlled for the costs of labor and equipment, hair tubes were 33.1% less expensive than visual sampling. Presence of squirrels and their nests was positively correlated with shrub species richness, indicating that the occurrence of forests with well-developed understory may inhibit the spread of the species.
KeywordsCallosciurus finlaysonii Early detection Hair tubes Nest selection Occupancy models
We thank Alessia D’Auria for assisting with laboratory procedures. This project did not receive any specific funding. Thanks also go to the associate editor who handled our paper and two anonymous reviewers whose recommendations helped us to improve our manuscript greatly.
Compliance with Ethical Standards
Conflict of Interest
The authors declare that they have no conflict of interest.
All procedures performed in studies involving wild species were in accordance with the ethical standards of the Institutional or National Research Committee and with approved ethical standards.
- Agostinelli C (2009) CircStats: circular statistics, from “Topics in Circular Statistics” (2001). R package version 0.2-4. http://CRAN.R-project.org/package=CircStats
- Aloise G, Bertolino S (2005) Free-ranging population of the Finlayson’s squirrel Callosciurus finlaysonii (Horsfield, 1824) (Rodentia, Sciuridae) in South Italy. Hystrix 16:70–74Google Scholar
- Braysher ML (1993) Managing vertebrate pests: principles and strategies. Australian Government Publishing Service, CanberraGoogle Scholar
- Burnham KP, Anderson DR (2002) Model selection and inference—a practical information-theoretic approach, 2nd edn. Springer, New YorkGoogle Scholar
- Lekagul B, McNeely JA (1977) Mammals of Thailand. Association for the Conservation of Wildlife, BangkokGoogle Scholar
- MacKenzie DI, Nichols JD, Royle JA, Pollock KH, Bailey LL, Hines JE (2006) Occupancy estimation and modeling. Inferring patterns and dynamics of species occurrence. Elsevier Academic Press Editions, Burlington, MAGoogle Scholar
- Mills LS, Citta JJ, Lair KP, Schwartz MK, Tallmond DA (2000) Estimating animal abundance using noninvasive DNA sampling: promise and pitfalls. Ecol Appl 10:283–294. https://doi.org/10.1890/1051-0761(2000)010[0283:EAAUND]2.0.CO;2 CrossRefGoogle Scholar
- Okubo M, Tamura N, Katsuki T (2005) Nest site and materials of the alien squirrel, Callosciurus erythraeus. Kanagawa prefecture. J Jpn Wildl Res Soc 31:5–10Google Scholar
- Oshida T, Torii H, Lin LK, Lee JK, Chen YJ, Endo H, Sasaki M (2007) A preliminary study on origin of Callosciurus squirrels introduced into Japan. Mamm Study 32:75–82. https://doi.org/10.3106/1348-6160(2007)32[75:APSOOO]2.0.CO;2 CrossRefGoogle Scholar
- Pignatti S (1982) Flora d’Italia. Edagricole, BolognaGoogle Scholar
- R Core Team (2014) R: a language and environment for statistical computing. R Foundation for Statistical Computing, ViennaGoogle Scholar
- Teerink BJ (1991) Hair of West-European mammals. Cambridge University Press, CambridgeGoogle Scholar
- Thompson W (2004) Sampling rare or elusive species: concepts, designs, and techniques for estimating population parameters. Island Press, Washington, DCGoogle Scholar
- Thorington RW, Koprowski JL, Steele MA, Whatton JF (2012) Squirrels of the world. John Hopkins University Press, Baltimore, MDGoogle Scholar
- Venturini M, Garrone A, Fasce E, Bertolino S, Balduzzi A (2008) L’uso di hair-tubes per il monitoraggio dello scoiattolo di Finlayson Callosciurus finlaysonii (Horsfield, 1923). Atti del 3° Workshop “Cantieri della Biodiversità”, 11–12 Settembre. Palazzo Squarcialupi, Siena, p 48Google Scholar
- White A, Lurz PWW, Bryce J, Tonkin M, Ramoo K, Bamforth L, Jarrott A, Boots M (2016) Modelling disease spread in real landscapes: squirrelpox spread in Southern Scotland as a case study. Hystrix. https://doi.org/10.4404/hystrix-27.1-11657