Biodiversity and Conservation

, Volume 22, Issue 13–14, pp 3223–3232

Evaluating the efficacy of land snail survey techniques in Hawaii: implications for conservation throughout the Pacific

  • Torsten H. Durkan
  • Norine W. Yeung
  • Wallace M. MeyerIII
  • Kenneth A. Hayes
  • Robert H. Cowie
Original Paper

Abstract

Terrestrial micromolluscs (snails with an adult maximum shell dimension <5 mm) constitute a considerable proportion of the land snail fauna of the Pacific. However, micromolluscs are often underestimated in biological surveys because of size bias. It has been argued that visual searches are preferable on Pacific islands because: (1) size biases are limited based on the understanding that most native Pacific island land snails are very small, and (2) amount of labor is less than other methods such as soil surveys and adequate for inventory purposes (though not for abundance assessments). To test whether visual surveys and soil surveys were accurately recording all taxa, land snail inventories were completed in three forest reserves (5 sampling sites in each) on the island of Oahu, Hawaii. Visual surveys involved 30-min visual search in a 10 m2 site; soil surveys involved sieving leaf litter and topsoil from four 0.3 m2 quadrats and extracting snails with the aid of a microscope. The data indicate a size and microhabitat bias associated with both techniques. Visual surveys consistently collected large arboreal and litter-dwelling species but missed a significant portion of micromolluscs, while soil surveys collected micromolluscs but missed larger snails. Because of such biases, employing both methods is critical for collecting all taxa at a survey location. As such, we recommend that future land snail surveys on Pacific Islands incorporate both survey techniques. Obtaining a complete inventory is critical if we are to understand species distributions and patterns of diversity and make well-informed conservation recommendations.

Keywords

Gastropoda Inventory Micromolluscs Mollusca Sampling methods 

References

  1. Barker GM, Mayhill PC (1999) Patterns of diversity and habitat relationships in terrestrial mollusc communities of the Pukeamaru Ecological District, northeastern New Zealand. J Biogeogr 26:215–238CrossRefGoogle Scholar
  2. Cameron RAD, Pokryszko BM (2005) Estimating the species richness and composition of land mollusc communities: problems, consequences and practical advice. J Conchol 38:529–547Google Scholar
  3. Christensen CC, Yeung NW, Hayes KA (2012) First records of Paralaoma servilis (Shuttleworth 1852) (Gastropoda: Pulmonata: Punctidae) in the Hawaiian Islands. Bishop Mus Occas Pap 112:3–7Google Scholar
  4. Clarke KR, Gorley RN (2001) V.5 users manual/tutorial PRIMER-E. PRIMER-E Ltd, PlymouthGoogle Scholar
  5. Cowie RH (1995) Variation in species diversity and shell shape in Hawaiian land snails: in situ speciation and ecological relationships. Evolution 49:1191–1202CrossRefGoogle Scholar
  6. Cowie RH (2001a) Invertebrate invasions on Pacific islands and the replacement of unique native faunas: a synthesis of the land and freshwater snails. Biol Invasion 3:119–136CrossRefGoogle Scholar
  7. Cowie RH (2001b) Decline and homogenization of Pacific faunas: the land snails of American Samoa. Biol Conserv 99:207–222CrossRefGoogle Scholar
  8. Cowie RH, Robinson AC (2003) The decline of native Pacific island faunas: changes in status of the land snails of Samoa through the 20th century. Biol Conserv 110:55–65CrossRefGoogle Scholar
  9. Cowie RH, Evenhuis NL, Christensen CC (1995) Catalog of the native land and freshwater molluscs of the Hawaiian Islands. Backhuys Publishers, LeidenGoogle Scholar
  10. Cowie RH, Hayes KA, Tran CT, Meyer WM III (2008) The horticultural industry as a vector of alien snails and slugs: widespread invasions in Hawaii. Int J Pest Manag 54:267–276CrossRefGoogle Scholar
  11. Emberton KC, Pearce TA, Randalana R (1996) Quantitatively sampling land-snail species richness in Madagascan rainforests. Malacologia 38:203–212Google Scholar
  12. Emberton KC, Pearce TA, Randalana R (1999) Molluscan diversity in the unconserved Vohimena and the conserved Anosy mountain chains, southeast Madagascar. Biol Conserv 89:183–188CrossRefGoogle Scholar
  13. Fontaine B, Gargominy O, Prié V (2011) Indigenous land snails. In: Bouchet P, Le Guyader H, Pascal O (eds) The natural history of santo. Muséum national d’Histoire naturelle, Paris, pp 169–178Google Scholar
  14. Gargominy O (2008) Beyond the alien invasion: a recently discovered radiation of Nesopupinae (Gastropoda: Pulmonata: Vertiginidae) from the summits of Tahiti (Society Islands, French Polynesia). J Conchol 39:517–536Google Scholar
  15. Gotelli NJ, Entsminger GL (2004) EcoSim: null models software for ecology. Version 7.0. Acquired Intelligence Inc. & Kesey-Bear. http://www.together.net/~gentsmin/ecosim.htm. Accessed 3 June 2013
  16. Legendre L, Legendre P (1983) Numerical ecology: developments in environmental modelling, 3rd edn. Elsevier, AmsterdamGoogle Scholar
  17. Liew T-S, Clements R, Schilthuizen M (2008) Sampling micromolluscs in tropical forests: one size does not fit all. Zoosymposia 1:271–280CrossRefGoogle Scholar
  18. Lydeard C, Cowie RH, Ponder WF, Bogan AE, Bouchet P, Clark S, Cummings KS, Frest TJ, Gargominy O, Herbert DG, Hershler R, Perez K, Roth B, Seddon M, Strong EE, Thompson FG (2004) The global decline of nonmarine mollusks. Bioscience 54:321–330CrossRefGoogle Scholar
  19. Menez A (2001) Assessment of land snail sampling efficacy in three Mediterranean habitat types. J Conchol 37:171–175Google Scholar
  20. Meyer WM III, Cowie RH (2010) Invasive temperate species are a threat to tropical island biodiversity. Biotropica 42:732–738CrossRefGoogle Scholar
  21. Nekola JC (2005) Geographic variation in richness and shell size of eastern North American land snail communities. Rec W Aust Mus Suppl 68:39–51Google Scholar
  22. Régnier C, Fontaine B, Bouchet P (2009) Not knowing, not recording, not listing: numerous unnoticed mollusk extinctions. Conserv Biol 23:1214–1221PubMedCrossRefGoogle Scholar
  23. Rundell RJ, Cowie RH (2003) Preservation of species diversity and abundances in Pacific island land snail death assemblages. J Conchol 38:155–169Google Scholar
  24. Sartori AF, Gargominy O, Fontaine B (2013) Anthropogenic extinction of Pacific land snails: a case study of Rurutu, French Polynesia, with description of eight new species of endodontids (Pulmonata). Zootaxa 3:343–372CrossRefGoogle Scholar
  25. Solem A (1990) How many Hawaiian land snail species are left? and what we can do for them. Bishop Mus Occas Pap 30:27–40Google Scholar
  26. Vermeulen JJ, Whitten AJ (1998) Fauna Malesiana: guide to the land snails of Bali. Backhuys Publishers, LeidenGoogle Scholar

Copyright information

© Springer Science+Business Media Dordrecht 2013

Authors and Affiliations

  • Torsten H. Durkan
    • 1
  • Norine W. Yeung
    • 1
    • 3
  • Wallace M. MeyerIII
    • 4
  • Kenneth A. Hayes
    • 1
    • 2
    • 3
  • Robert H. Cowie
    • 1
  1. 1.Pacific Biosciences Research CenterUniversity of HawaiiHonoluluUSA
  2. 2.Department of BiologyHoward UniversityWashingtonUSA
  3. 3.Smithsonian InstitutionNational Museum of Natural HistoryWashingtonUSA
  4. 4.Department of BiologyPomona CollegeClaremontUSA

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