Overcoming hermit-crab interference during rodent-baiting operations: a case study from Henderson Island, South PacificR. J. Cuthbert A D , M. de L. Brooke B and N. Torr C
A Royal Society for the Protection of Birds, The Lodge, Sandy, Bedfordshire SG19 2DL, United Kingdom.
B Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, United Kingdom.
C 64 Mokonui Street, Te Anau, New Zealand.
D Corresponding author. Email: firstname.lastname@example.org
Wildlife Research 39(1) 70-77 https://doi.org/10.1071/WR11033
Submitted: 17 February 2011 Accepted: 7 November 2011 Published: 27 February 2012
Context: Rat (Rattus spp.) eradication operations in the tropics are often put at risk by the presence of land crabs, in particular hermit crabs (Coenobitidae), which consume toxic bait and thereby render it unavailable to rats.
Aims: We estimated hermit-crab densities in areas of high abundance, assessed crab bait consumption rates and determined the required baiting application rate to ensure that 100% of Pacific rats (Rattus exulans) consumed bait in areas with high crab densities on Henderson Island, South Pacific.
Methods: Crab densities and rat densities were estimated through Distance sampling of crabs and mark–recapture of rats. Non-toxic rhodamine-dyed cereal bait pellets were spread by hand at varying densities within four study plots and rats were captured 12 days later and examined for the presence of rhodamine biomarker dye.
Key results: Crab densities (primarily Coenobita perlatus) varied between beaches from 130 crabs ha–1 to 1370 crabs ha–1, with rats occurring at respective densities of 28 and 7 rats ha–1 on these beaches. Estimated bait consumption rate of C. perlatus was 3.8 g crab–1 day–1. In total, 100% of rats were positive for rhodamine-dyed bait, despite the high densities of crabs present.
Conclusions: The results support the prospects for a successful rat eradication on Henderson Island, although careful consideration must be given to the potential impact of an eradication on non-target species. The estimated bait consumption rate by C. perlatus found in the present study may allow other eradication operations to make initial calculations of the required baiting densities to overcome interference from this species.
Additional keywords: Coenobitidae, conservation, eradication, islands, rats, Rattus exulans.
ReferencesAtkinson, I. A. E. (1985). The spread of commensal species of Rattus to oceanic islands and their effect on island avifaunas. In ‘Conservation of Island Birds. Case Studies for the Management of Threatened Island Species’. (Ed. P. J. Moors.) pp. 35–81. Technical Publication 3. (International Council for Bird Preservation: Cambridge, UK.)
Brooke, M. de L., and Towns, D. R. (2008). ‘A Feasibility Study for the Eradication of Kiore Rattus exulans from Henderson Island.’ (Royal Society for the Protection of Birds: Sandy, UK.)
Brooke, M. de L., O’Connell, T. C., Wingate, D., Madeiros, J., Hilton, G. M., and Ratcliffe, N. (2010a). Potential for rat predation to cause decline of the globally threatened Henderson petrel Pterodroma atrata: evidence from the field, stable isotopes and population modelling. Endangered Species Research 11, 47–59.
| Potential for rat predation to cause decline of the globally threatened Henderson petrel Pterodroma atrata: evidence from the field, stable isotopes and population modelling.CrossRef |
Brooke, M. de L., Cuthbert, R. J., Henricson, A., Torr, N., Warren, P., and O’Keefe, S. (2010b). Towards rat eradication on Henderson Island: fieldwork report August–September 2009. Royal Society for the Protection of Birds, Sandy, UK.
Brooke, M. de L., Cuthbert, R. J., Mateo, R., and Taggart, M. A. (2011). An experimental test of the toxicity of cereal pellets containing brodifacoum to the snails of Henderson Island, South Pacific. Wildlife Research 38, 34–38.
| An experimental test of the toxicity of cereal pellets containing brodifacoum to the snails of Henderson Island, South Pacific.CrossRef |
Broome, K. (2006). ‘Current Agreed Best Practice for Rat Eradication – Aerial Application of Brodifacoum Cereal Bait.’ (New Zealand Department of Conservation: Hamilton, New Zealand.)
Brown, D. (2008). ‘An Operational Plan for the Eradication of Kiore Rattus exulans from Henderson Island.’ (Royal Society for the Protection of Birds: Sandy, UK.)
Burggren, W. W., and McMahon, B. R. (Eds) (1988). ‘Biology of the Land Crabs.’ (Cambridge University Press: Cambridge, UK.)
Cunningham, D. M., and Moors, P. J. (1996). ‘Guide to the Identification and Collection of New Zealand Rodents.’ 3rd edn. (New Zealand Department of Conservation: Wellington, New Zealand.)
Fisher, P. (1999). Review of using rhodamine B as a marker for wildlife studies. Wildlife Society Bulletin 27, 318–329.
Griffiths, R., Climo, G., and Gouni, A. (2008). Ecological restoration of Vahanga Atoll, Acteon Group, Tuamotu Archipelago. Research report to Pacific Invasives Initiative, Auckland, New Zealand.
Groombridge, B. (1992). ‘Global Biodiversity: Status of the Earth’s Living Resources: a Report. World Conservation Monitoring Centre, British Museum (Natural History), International Union for Conservation of Nature and Natural Resources.’ (Chapman & Hall: London.)
Hilton, G. M., and Cuthbert, R. J. (2010). The catastrophic impact of invasive mammalian predators on birds of the UK Overseas Territories: a review and synthesis. The Ibis 152, 443–458.
| The catastrophic impact of invasive mammalian predators on birds of the UK Overseas Territories: a review and synthesis.CrossRef |
Howald, G., Samaniego, A., Buckelew, S., McClelland, P., Keitt, B., Wegmann, A., Pitt, W. C., Vice, D. S., Campbell, E., Swift, K., and Barclay, S. (2004). Palmyra rat eradication assessment. Unpublished report, Island Conservation, Santa Cruz, CA.
Howald, G., Donlan, C. J., Galvan, J. P., Russell, J. C., Parkes, J., Samaniego, A., Wang, Y., Veitch, D., Genovesi, P., Pascal, M., Saunders, A., and Tershy, B. (2007). Invasive rodent eradication on islands. Conservation Biology 21, 1258–1268.
| Invasive rodent eradication on islands.CrossRef |
Island Conservation (2011). ‘Working-draft Operational Plan: Palmyra Atoll Rat Eradication Project – Alternative C (Preferred Alternative) v. 4/28/2011.’ Available at http://www.fws.gov/palmyraatoll/Palmyra%20Rat%20Eradication%20Operational%20Plan_WORKING%20DRAFT_28April11_redact3.pdf [accessed 3 October 2011].
Jones, H. P., Tershy, B. R., Zavaleta, E. S., Croll, D. A., Keitt, B. S., Finkelstein, M. E., and Howald, G. R. (2008). Severity of the effects of invasive rats on seabirds: a global review. Conservation Biology 22, 16–26.
| Severity of the effects of invasive rats on seabirds: a global review.CrossRef |
Krebs, C. J. (1999). ‘Ecological Methodology.’ 2nd edn. (Addison-Wesley Educational Publishers, Inc.: New York.)
O’Connor, C. E., and Booth, L. H. (2001). Palatability of rodent baits to wild house mice. Science for Conservation 184. Department of Conservation, Wellington, New Zealand.
Pain, D., Brooke, M. de L., Finnie, J. K., and Jackson, A. (2000). Effects of brodifacoum on the land crab Gecarcinus lagostoma on Ascension Island: acute effects, persistence and distribution in tissues. The Journal of Wildlife Management 64, 380–387.
| Effects of brodifacoum on the land crab Gecarcinus lagostoma on Ascension Island: acute effects, persistence and distribution in tissues.CrossRef |
Pierce, R., Anterea, N., Anterea, U., Broome, K., Brown, D., Cooper, L., Edmonds, H., Muckle, F., Nagle, B., Oakes, G., Thorsen, M., and Wragg, G. (2008). Operational work undertaken to eradicate rats and rabbits in the Phoenix Islands, Kirbati, May–June 2008. Pacific Expeditions Ltd report for Government of Kiribati, NZ Department of Conservation, NZAID and Pacific Invasives Initiative.
Thomas, L., Buckland, S. T., Rexstad, E. A., Laake, J. L., Strindberg, S., Hedley, S. L., Bishop, J. R. B., Marques, T. A., and Burnham, K. P. (2010). Distance software: design and analysis of distance sampling surveys for estimating population size. Journal of Applied Ecology 47, 5–14.
| Distance software: design and analysis of distance sampling surveys for estimating population size.CrossRef |
Varnham, K. (2010). Invasive rats on tropical islands: their history, ecology, impacts and eradication. RSPB Research Report No. 41. Royal Society for the Protection of Birds, Sandy, Bedfordshire, UK.
Wegmann, A. (2008). Land crab interference with eradication projects: Phase I – compendium of available information. Pacific Invasives Initiative. The University of Auckland, New Zealand.
Wegmann, A., Helm, J., Golding, C., and Torr, N. (2009). Wake Atoll rat eradication operational plan: biomarker study trip report (27 February to 27 March 2009). Island Conservation, Kelowna, Canada.