Occupancy modeling of the Nimapuna tigersnail, a terrestrial gastropod endemic to Idaho

Publication Type:



Idaho Department of Fish and Game, Lewiston, ID, p.[14] (2012)

Call Number:



Anguispira nimapuna, Nimapuna disc, Nimapuna tigersnail, SWAP


This report discusses methods and results of 2012 survey work using a spatially balanced sampling design to survey the forest gastropod community across the Selway-Middle Fork Clearwater Collaborative Forest Landscape Restoration Program (CFLRP) project area. Specific objectives were to assess the area of occupancy of the Nimapuna tigersnail [disc] (Anguispira nimapuna) (NITS) and identify habitat variables that explain variation in its distribution across the project area. Estimates of occupancy are an indirect measure of a population’s status and are generally less intrusive and less expensive than direct measures such as estimating abundance and survival (Schultz et al. 2012). Results show that the distribution of NITS within the Selway-Middle Fork CFLRP areas is much wider than previously thought and suggest that elevation better describes distribution than proximity to streams. Data did not support any model with distance to stream describing occupancy. Though this work represents a significant improvement in knowledge of the ecology and distribution of NITS, necessary information is still lacking to adequately identify and address threats to the species. The authors recommend additional surveys in areas adjacent to the study area and the collection of more detailed habitat data at sample sites, including disturbance history, to better identify habitat associations.


ELECTRONIC FILE - Zoology: Invertebrates

SWAP (2/19/16) citation [with page numbers added]:
Baumgardt JA, Sauder JD. [2012]. Occupancy modeling of the Nimapuna tigersnail, a terrestrial gastropod endemic to Idaho. Lewiston (ID): Idaho Department of Fish and Game. [14 p.].

NOTE: See also A12BAU02IDUS. ALSO note that the specific locations for Nimapuna tigersnail sightings are included in our U12BAU01IDUS folder in shape files, along with files that include our OBSNOs.