LAND SNAILS

Land snails are the most threatened group of land animals.

 Pearly tuba Chondropoma-sp.

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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 shells.

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 54(4):321-330.).

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 rapidly deforested.

Land snails and sustainability

Bioindicators

Tropical snails are good bioindicators for conservation priorities for vertebrates, but not vice versa.

Land 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 fungi.

 Princess-cone-Orthalicus-princeps-  

Ron Caldwell and Robert Browne 

Left: The princess cone, Orthalicus princeps, is the largest land snail in the Sartenejan region. Image Robert BrowneRight: Prof. Ron Caldwell and Dr. Robert Browne surveying for land snails on B'alam Ja Way. Image Cuperto Flores.



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

Sustainability 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 decline.

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

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 own.

 Sartenejan-quill-Brachypodella-sp

 

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.

Ecological studies

The food sources, reproduction, predation, and essential habitat are unknown for most land molluscs, and therefore the specific ecological role land moluscs play in ecosystems.

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.