Mature exotic conifer stands have greater catches of the EU-protected Geomalacus maculosus than adjacent peatland or clear-felled stands—implications for forestry
Mature exotic Sitka spruce ( Picea sitchensis ; Bong. Carrière)-dominated stands, particularly trees of greater circumference, result in greater numbers of Geomalacus maculosus (Allman) captures than adjacent clear-felled stands and adjacent peatland with Before-After-Control-Impact-Paired analysis indicating lower catches of G. maculosus post-felling.
The discovery of EU-protected Geomalacus maculosus in commercial plantations requires an understanding of the implications of forestry practices for the species within the context of sustainable forest management.
Compare Geomalacus maculosus captures across mature exotic Sitka spruce-dominated stands, previously clear-felled stands and adjacent peatland habitats.
Assess the suitability, for forest managers, of population estimate models for G. maculosus.
Assess the implications of felling by comparing relative abundances of G. maculosus directly before and after clear-felling at a mature exotic Sitka spruce-dominated stand.
Geomalacus maculosus catches were compared at four sites across two to three mature (43–45 years old) conifer stands per site, one clear-felled stand per site, and one adjacent peatland per site using refuge traps and hand searching. Capture-mark-recapture studies were undertaken to estimate population sizes. A BACIP (Before-After-Control-Impact-Paired) analysis was undertaken in one forest stand at one forest site to determine impacts of a clear-felling event.
Mean catches of Geomalacus maculosus adults in the mature forest stands were over 10 and 11 times greater than mean catches on peatland and clear-fell stands, respectively. The Schnabel model for estimating population size was most suited for mature forest stands but could not be utilised for the other habitats. BACIP analysis showed a significant impact of clear-felling with a 95% reduction in mean G. maculosus catches after a clear-felling event where none of the individuals marked prior to felling were recaptured compared to 21% recapture rates at the control site. Greater tree circumference in mature conifer stands correlated with greater catches.
Guidelines are needed to ensure the protection of Geomalacus maculosus in commercial forestry. Interventions could include patch/tall stump retention at final felling and/or translocation of the protected species.
KeywordsConservation Capture-mark-recapture Population estimates Before-After-Control-Impact-Paired (BACIP) Slug
We are grateful to Aidan O’Hanlon, Clément Teillet, Declan McGovern, Lorenzo Sardo, Mark Welch, Úna Ní Ruairc and Frank O’Grady for assistance with fieldwork. We would also like to thank Stacey Bradly, Eamon Drohan, Joan O’Connor, Ted Kelleher, Padraig McMahon and Ciaran Walsh (Coillte) for providing information on the sites and Coillte for permitting access to the sites. Thank you to Dr. Aileen O Sullivan (Coillte) and Dr. Orla Fahy (Forest Service) for their assistance. We acknowledge, with thanks, the Wildlife Licensing Unit (National Parks & Wildlife Service) for providing us with licence no. C069/2014 and the Department of Agriculture, Food and the Marine for funding this research under the FIRM/RSF/CoFoRD 2013 Research Call. Finally, we wish to thank the reviewers and editors for their insightful and helpful comments.
This project was funded by the Department of Agriculture, Food and the Marine under the FIRM/RSF/CoFoRD 2013 Research Call.
- Alcoy JCO (2013) The Schnabel method: an ecological approach to productive vocabulary size estimation. Int Proc Econ Dev Res 68:19Google Scholar
- ANON (2010). Threat response plan kerry slug Geomalacus maculosus. National Parks & Wildlife ServiceGoogle Scholar
- Carnus M, Parrotta J, Brockerhoff E, Arbez M, Jactel H, Kremer A, Lamb D, O’Hara K, Walters B (2006) Planted forests and biodiversity. J Forest 104:65–77Google Scholar
- Coillte (2014) Inventory list for fieldwork surveys (full). Coillte TeorantaGoogle Scholar
- DAFM (2016) Ireland’s forests—annual statistics. Department of Agriculture, Food and the MarineGoogle Scholar
- Forest Service (2009) Forestry and Kerry slug guidelines. Department of Agriculture, Fisheries and Food, Dublin. http://www.agriculture.gov.ie/forestservice/publications/ Google Scholar
- FSC (2016) The 10 Principles. Ten rules for responsible forest management. Retrieved from: https://ic.fsc.org/en/certification/principles-and-criteria/the-10-principles
- Greenwood J, (1996) Basic techniques. In: Sutherland WJ, (1996) Ecological census techniques, a handbook. Cambridge University Press, Cambridge, 11-11DGoogle Scholar
- Johnston E, Kindermann G, O’Callaghan J, Burke D, McLaughlin C, Horgan S, Mc Donnell R, Williams C, Gormally M (2017) Monitoring the EU protected Geomalacus maculosus (Kerry slug): what are the factors affecting catch returns in open and forested habitats? Ecol Res 32(1):95–104. https://doi.org/10.1007/s11284-016-1412-5 CrossRefGoogle Scholar
- Kearney J (2010) Kerry slug (Geomalacus maculosus Allman, 1843) recorded at Lettercraffroe, Co. Galway. Ir Nat J 31:68–69Google Scholar
- Krebs CJ (1999) Ecological methodology, 2nd edn. A. Wesley Longman, NYGoogle Scholar
- Mc Donnell R, Gormally M (2011) A live trapping method for the protected European slug, Geomalacus maculosus Allman 1843 (Arionidae). J Conchol 1843:483–485Google Scholar
- Northwest Marine (2015) Visible implant elastomer tag project manual. Guidelines on planning and conducting projects using VIE and associated equipmentGoogle Scholar
- NPWS (2013) The status of EU protected habitats and species in Ireland. Species assessments volume 3. Version 1.0. National Parks & Wildlife Services. Department of Arts, Heritage and the Gaeltacht, DublinGoogle Scholar
- Prior DJ (1985) Water-regulatory behaviour in terrestrial gastropods. Biol Rev 60(3):403–424. https://doi.org/10.1111/j.1469-185X.1985.tb00423.x CrossRefPubMedGoogle Scholar
- Rancka B, von Proschwitz T, Hylander K, Gotmark F (2015) Conservation thinning in secondary forest: negative but mild effect on land molluscs in closed-canopy mixed oak forest in Sweden. Plos One 10(3):e0120085. https://doi.org/10.1371/journal.pone.0120085
- Reich I, O’Meara K, Mc Donnell RJ, Gormally MJ (2012) An assessment of the use of conifer plantations by the Kerry slug (Geomalacus maculosus) with reference to the impact of forestry operations. In: Irish Wildlife Manuals, No. 64 edn. National Parks and Wildlife Service, Department of Arts, Heritage and the Gaeltacht, IrelandGoogle Scholar
- Reich I (2015) The EU-protected slug Geomalacus maculosus: an investigation into its phylogenetics, population densities in conifer plantations and its gut microbial community. PhD Dissertation National University of Ireland GalwayGoogle Scholar
- Reich I, Mc Donnell R, Mc Inerney C, Callanan S, Gormally M (2017) EU-protected slug Geomalacus maculosus and sympatric Lehmannia marginata in conifer plantations: what does mark-recapture method reveal about population densities? J. Mollus. Stud. 83(1):27–35. https://doi.org/10.1093/mollus/eyw039 CrossRefGoogle Scholar
- Scharff R (1893) Note on the geographical distribution of Geomalacus maculosus, Allman, in Ireland. J Mollus Stud 1893:17–18Google Scholar
- Sutherland WJ (1996) Ecological census techniques, a handbook. Cambridge University Press, Cambridge, pp 11–11DGoogle Scholar
- Young AG, Port GR, (1989). Effect of microclimate on slug activity in the field. Monograph-British Crop Protection CouncilGoogle Scholar