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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 biogeography 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.
Research in the lab incorporates both ecological and evolutionary approaches.
Questions addressed include: 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?
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. The lab is
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 systematics,
biogeographic origins and phylogenetic relationships of the pest species (using
molecular and morphological 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.
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