Land snails are the most threatened group of land
SfS is conducting genetic
assessment of species to build a solid inventory of species in the region. We
are also assessing land mollusks as bioindicator for other rainforest
species, and developing programs their use in environmental
education as they are easily identified from thier
Left: Recent studies by SfS identified the pearly tuba is one of the
four types of tuba snails (Chondropoma
spp.) found in the Sartenejana Region.
Image Robert Browne.
The loss and decline of many vertebratel species such
as mammals, birds, amphibians and reptiles have been documented and feature in popular
media. However, many invertebrate species, which comprise nearly 99% of all animal diversity
are either already extinct or severely threatened (Ponder and Lunney 1999). These invertebrates
are less known to the public and researched than vertebrates.
Land and freshwater mollusks, snails and slugs, freshwater clams
and mussels, are one of the most diverse and threatened groups of
invertebrates. There are approximately 24,000 terrestrial
and 7000 freshwater mollusk species already described, and the same numbers of species probably
remain undescribed (The global decline of nonmarine mollusks. BioScience
Land or freshwater mollusks have the highest percentage (40%)
of extinctions of any animal group (Lydeard et al. 2004). However, only 2% of known mollusc
species have had their conservation status and threats to their survival
assessed. A particular threat is the ongoing discovery of large numbers of
mollusk species in a very small areas of the tropics. Many of these areas are being
Land snails and
Tropical snails are good bioindicators
for conservation priorities for vertebrates, but not vice versa.
snails easy to survey through their dead shells, and land snails include both
generalists and specialists in respect to habitat requirements.
Land snails can be
assessed year round from their dead shells. Land snail inventories are economical in cost
and time, and areas of under 5 hectares can hold
85-95% of the locally occurring land snails.
Land snail inventories are good bioindicators for
assessing ecosystem health. Land snails include small
generalist species that occur in large numbers in leaf litter, and rarer species that are more
sensitive to environmental change such as larger carnivores and species that feed on special
Left: The princess cone, Orthalicus princeps, is the
largest land snail in the Sartenejan
region. Image Robert
Browne. Right: Prof. Ron Caldwell and Dr. Robert Browne surveying for land snails
on B'alam Ja Way. Image Cuperto
Land snail inventories can show
both large and small scale changes in thier ecosystem. Information on
ecosystem change is valuable to show the degradation
of forest ecosystems before the effect of
environmental threats on trees is obvious.
Integrating mollusc surveys into terrestrial and freshwater
biodiversity surveys should also be a priority. There is a
need for particular conservation measures to protect land and freshwater molluscs, other
invertebrates, and fungi.
Education about the importance of land snails as a
major component of global biodiversity is a high priority to lessen their rate of extinction and
The general public and policymakers should be informed of the
integral role land and freshwater mollusks play in ecosystems.
Bioliteracy that includes land and freshwater mollusks and other invertebrates, must be
integrated in the general curriculum from kindergarten through college.
Networking offers the potential to both publicise and popularise
land molluscs. This foundation then lays the way to greater increased resources and focus for the
sustainable management of molluscs.
Web sites and Facebook groups should be used by both professional
and private mollusc conservationists to publicise their work and interest. Web sites should
interlink with as many other similar websites as possible.
Scientists and other experts should
share their knowledge through educational presentations and field trips.Land snail
diversity is valuable both for its own
sake and as an indicator of conditions that may affect other species, including our
Left: Most land snails are quite small with these
Sartenejan quills Brachypodella sp.
being among the larger of the small species that my be as small as 1mm. The
Sartenejan Region promises the discovery of many new species of land snails.
Image Robert Browne.
The food sources, reproduction, predation, and essential habitat
are unknown for most land molluscs, and therefore the specific ecological role land moluscs play in
Land snails only rarely been used as indicator species and are
highly underrepresented in conservation research.
An advantage to using
land snails as bio-indicators is that they can be harvested year round with little or no impact to
the species, given that most shells collected (upwards to 90%) are without live animals.
Furthermore, land snail inventories can be speedy and comprehensive (saving time and money). For
example, research suggests that relatively small areas (under 5 hectares) can hold most (85-95%) of
the locally occurring land snail fauna.