Glyptostoma gabrielense

This terrestrial snail is endemic to one area on the edge of and within Greater Los Angeles. The threats are high and the overall range extent is not large, however, it is found in many locations within the area.

This snail is endemic to the San Gabriel Mountains and foothills near and within Greater Los Angeles, California, USA. It has a known range extent of approximately 2400 km2.

There are 22 mapped occurrences in the California Natural Diversity Database (2022) and approximately 30 more as mapped to research grade in iNaturalist (accessed January 2023).

The assessment of the threats for this species are roughly divided between the Angeles National Forest and adjacent National Forest and other protected areas in the northern approximate half of the current range and the developed urban areas and patches of undeveloped land to the south.

Fire is a major threat to the northern areas as well as within non-developed areas (California Fire Hazard Severity Zones 2022). Fire will impact the snails by killing them directly, and then indirectly by destroying the trees and overstory leading to drier conditions, by burning ground debris including logs and leaf litter, as well as the increased incidences of landslides and floods (Curry 2017). In an attempt to counter the threat of fires and reduce the severity there have been programs in the forests to reduce the fire fuel loads which entails the removal of downed dead and woody debris (the snail's habitat) and controlled burns (USFS 2023). The frequency and intensity of fires have increased over at least the past 40 years, exasperating this threat. In much of the urbanized and industrial areas the development has already happened and is likely as developed as it will get, however, there are a few areas that appear as though development still could occur which will destroy that habitat. This is also the case for logging except in the areas where logging is done as a fire reduction measure.

With approximately 20 million people in the area, these natural areas undergo high usage with activities like hiking, mountain biking, camping and stone flipping. Generally land snails are tolerant to a moderate level of these activities, however the intensity and high volume in this case is likely to cause some disturbance and mortality. The mortalities caused by the road building within the developed urban areas has already occurred and could have a timing of "past", however there is continual maintenance with the accompanying runoff and land disturbance as well as direct mortality of snails attempting to disperse. New roads to accommodate more users (population of the area is increasing) within the national forest and protected areas will cause habitat loss.

Herbicides that are used along roadsides, depending on their types, can be fatal to snails.