Research Interests

My research program is aimed at understanding the origins and determinants of biological diversity in the islands of the Pacific. Hawaii is the perfect place to base this work. My research has been supported by NSF and other granting agencies and has generated numerous publications, many in top-ranked journals (e.g., Evolution, American Naturalist). I am using non-marine snails (land and freshwater) as a model. The advantages of using snails are that 1) they are diverse in the Pacific but not unmanageably so; 2) they are relatively sedentary and thus easily collected and sampled accurately; 3) much of the inter- and intra-specific variation manifested by them is readily recorded by simple methods; 4) the shell remains intact for a considerable time in the field after the animal has died; and 5) there are immense and well-documented museum collections from throughout the Pacific basin going back over a century, including alcohol preserved specimens from which DNA can be extracted.

I am investigating important questions in Pacific biodiversity and related issues from a number of different directions, as follows.

Evolutionary and ecological determinants of non-marine snail diversity

The study of patterns of species diversification is developing rapidly, especially in an evolutionary context, as a complement to the seminal but over-simplistic "theory of island biogeography". Historical biogoegraphy is now at the forefront of evolutionary biology as modern phylogenetic methodologies are applied to questions of the geographic and evolutionary origins of biological diversity. My research incorporates both ecological and evolutionary approaches. Questions I am addressing are: what ecological factors influence distribution patterns; what determines numbers of species on particular islands and archipelagos; what are the geographic and phylogenetic origins of Pacific island land snails? These issues have become the central core of my research over the last few years, funded in part by NSF and USGS/BRD, and have incorporated modern molecular techniques of DNA analysis to develop phylogenies that are the necessary prerequisites for answering many of these evolutionary and ecological questions.

Conservation and alien species

The fascinating diversity that has prompted the above research is, however, disappearing. Thus, conservation of the unique island faunas is of crucial importance. I am involved in three main areas addressing conservation issues, focused not only in Hawaii but covering the entire insular Pacific.

1. Invasion biology - Invasion biology is one of the fastest-growing and important areas of conservation biology. Much of my recent research has focused on alien species, and especially on the patterns and processes of faunal homogenization in Hawaii and throughout the islands of the Pacific, the specific impacts of certain alien species, and the worldwide pathways via which they are spread.
2. Apple snails -Dealing with alien species in general, led me to become involved more closely with introduced crop-damaging freshwater snails ("apple snails") in Hawaii and South-East Asia. These highly invasive snails have the potential to cause enormous ecological damage. The main focus of this work has been to understand the dynamics of the invasions, using the snails as a model to address the underlying causes of invasiveness. We are researching the biogeographic origins and phylogenetic relationships of the pest species (using molecular techniques).
3. Conservation ecology -One of the most fundamental questions in conservation biology is why some native species are more vulnerable to extinction (especially in the face of alien invasions) than others. Ecological characteristics of the species are obviously important and have prompted much speculation. Among the native Hawaiian and Pacific snails, some seem less vulnerable than others to the suite of threats they are faced with. In Hawaii, the Succineidae are one of the groups seemingly least in decline. We have begun to investigate reasons for the succineids' relative immunity to these threats. Questions to be asked include the following. Why are succineids in Hawaii still abundant? In fact only some of them are; others seem very rare or gone; why is that? Is life-history important? How does succineid life-history differ from that of better known but more precarious species (e.g., Achatinellinae)? What are succineid habitat and food preferences? Can they survive in non-native habitat? Probably some of them can-why? What are the food preferences of the alien predatory snail Euglandina rosea, which is one of the major scourges of other native Hawaiian and Pacific land snails? What are its ecological limits? Basic ecological research of this kind is essential for understanding the potential for conserving the native species and for directly addressing management options.

Snail shell coiling and asymmetry

Snails' shells are their most obvious feature, and the characteristics of the coil have attracted interest for centuries. All biologists have probably at some time wondered why most snail shells coil to the right. A complementary question is why a significant minority nevertheless coil to the left. As something of a subsidiary research area, I am looking at worldwide faunas to address this fundamental question in molluscan evolutionary biology. Pacific island tree snail species are unusual because some of them are polymorphic for coil direction. Using these Pacific species, my Japanese colleagues and I are currently investigating why dextrally coiling shells are not exact mirror-images of sinistrally coiling shells of the same species, a question first addressed by Stephen J. Gould and fundamental to an understanding of the evolution of the gastropod shell and more generally to biological asymmetry.

Cowie, R.H. & Robinson, A.C. 2003. The decline of native Pacific island faunas: changes in status of the land snails of Samoa through the 20th century. Biological Conservation 110: 55-65.

Cowie, R.H., Rundell, R.J., Mika, F. and Setu, P. 2002. The endangered partulid tree snail Samoana thurstoni on Olosega and the land snail diversity of the Manu'a Islands, American Samoa. American Malacological Bulletin 17(1/2): 37-43.

Cowie, R.H. & Rundell, R.J. 2002. The land snails of a small tropical Pacific island, Aunu'u, American Samoa. Pacific Science 56(2): 143-147.

Cowie, R.H. 2002. Invertebrate invasions on Pacific islands and the replacement of unique native faunas: a synthesis of the land and freshwater snails. Biological Invasions 3(3)[2001]: 119-136.

Cowie, R.H. 2002. Apple snails (Ampullariidae) as agricultural pests: their biology, impacts and management. In: Molluscs as Crop Pests (ed.G.M. Barker), p. 145-192. CABI Publishing, Wallingford.

Staples, G.W. & Cowie, R.H. (eds.) 2001. Hawai'i's Invasive species. A guide to invasive plants and animals in the Hawaiian Islands. Mutual Publishing & Bishop Museum Press, Honolulu. xii + 116 p.

Lach, L., Britton, D.K., Rundell, R.J. & Cowie, R.H. 2001. Food preference and reproductive plasticity in an invasive freshwater snail. Biological Invasions 2(4)[2000]: 279-288.

Cowie, R.H. 2001. Can snails ever be effective and safe biocontrol agents? International Journal of Pest Management 47(1): 23-40.

Cowie, R.H. & Cook, R.P. 2001. Extinction or survival: partulid tree snails in American Samoa. Biodiversity and Conservation 10(2): 143-159.

Cowie, R.H. 2001. Decline and homogenization of Pacific faunas: the land snails of American Samoa. Biological Conservation 99(2): 207-222.

Cowie, R.H., Kabat, A.R. & Evenhuis, N.L. 2001. Ampullaria canaliculata Lamarck, 1822 (currently Pomacea canaliculata; Mollusca, Gastropoda): proposed conservation of the specific name. Bulletin of Zoological Nomenclature 58(1): 13-18.

Lach, L., Britton, D.K., Rundell, R.J. & Cowie, R.H. 2001. Food preference and reproductive plasticity in an invasive freshwater snail. Biological Invasions 2(4)[2000]: 279-288.

Staples G.W. & Cowie, R.H. (eds.) 2001. Hawai'i's Invasive species. A guide to invasive plants and animals in the Hawaiian Islands. Mutual Publishing & Bishop Museum Press, Honolulu. xii + 116 p.

Cowie, R.H. 2000. Non-indigenous land and freshwater molluscs in the islands of the Pacific: conservation impacts and threats. In: Invasive species in the Pacific: a technical review and regional strategy (ed. G. Sherley), p. 143-172. South Pacific Regional Environment Programme, Apia.

Lach, L. & Cowie, R.H. 1999. The spread of the introduced freshwater apple snail Pomacea canaliculata (Lamarck) (Gastropoda: Ampullariidae) on O'ahu, Hawai'i. Bishop Museum Occasional Papers 58: 66-71.

Asami, T., Cowie, R.H. & Ohbayashi, K. 1998. Evolution of mirror images by sexually asymmetric mating behavior in hermaphroditic snails. American Naturalist 152(2): 225-236.

Cowie, R.H. 1998. Patterns of introduction of non-indigenous non-marine snails and slugs in the Hawaiian Islands. Biodiversity and Conservation 7(3): 349-368

Cowie, R.H. 1998. Catalog of the nonmarine snails and slugs of the Samoan Islands. Bishop Museum Bulletins in Zoology 3, viii + 122 p.

Cowie, R.H. 1997. Pila Roding, 1798 and Pomacea Perry, 1810 (Mollusca, Gastropoda): proposed placement on the Official List, and Ampullariidae Gray, 1824: proposed confirmation as the nomenclaturally valid synonym of Pilidae Preston, 1915. Bulletin of Zoological Nomenclature 54(2): 83-88.

Cowie, R.H. 1997. Catalog and bibliography of the nonindigenous nonmarine snails and slugs of the Hawaiian Islands. Bishop Museum Occasional Papers 50: 1-66.

Cowie, R.H. 1996. Variation in species diversity and shell shape in Hawaiian land snails: in situ speciation and ecological relationships. Evolution 49(6)[1995]: 1191-1202.

Cowie, R.H. 1996. Pacific island land snails: relationships, origins, and determinants of diversity. In: The origin and evolution of Pacific island biotas, New Guinea to eastern Polynesia: patterns and processes (Eds. Keast, A. & Miller, Scott E.), pp. 347-372. SPB Academic Publishing, Amsterdam.

Cowie, R.H. 1995. Identity, distribution and impacts of introduced Ampullariidae and Viviparidae in the Hawaiian Islands. Journal of Medical and Applied Malacology 5[for 1993]: 61-67.

Cowie, R.H., Evenhuis, N.L. & Christensen, C.C. 1995. Catalog of the native land and freshwater molluscs of the Hawaiian Islands. Backhuys Publishers, Leiden. vi + 248 pp.

Cowie, R.H., Nishida, G.M., Basset, Y. & Gon, S.M., III. 1995. Patterns of land snail distribution in a montane habitat on the island of Hawaii. Malacologia 36(1-2): 155-169.

Cowie, R.H. 1992. Evolution and extinction of Partulidae, endemic Pacific island land snails. Philosophical Transactions of the Royal Society of London Series B Biological Sciences 335: 167-191.

Cowie, R.H. (Editor) 1992. The impact of alien species on island ecosystems. Pacific Science 46(3): 383-404.