Amphibian and reptile survey of the Bitterroot National Forest

Description

A total of 27 site surveys of ponds, lakes, river channels and hillside slopes at 23 sites, and 85 additional opportunistic sightings of reptiles and amphibians, were made on and near the Bitterroot National Forest during March to October, 1995. Most surveys were performed by a single individual. Two ponds were visited at least twice, assessed as future amphibian monitoring sites, and one of these was surveyed four times (once a month from May to August). Each survey took 10-60 minutes (mean = 23 minutes) and consisted of a thorough search of the wetland perimeter and netting of near shore aquatic habitat for larvae and tadpoles. Stream sampling was done by hand and dipnet. Opportunistic sighting were compiled from road kills, vocal identifications, fortuitous encounters with live animals, and reports from reliable individuals. Historical records of reptiles and amphibians on or near the Bitterroot National Forest were compiled from museum collections, unpublished reports and the published literature. Efforts were made to sample wetland habitats at different elevations throughout the entire forest, but due to time constraints, weather conditions, and the large area with relative difficult accessibility, the majority of surveys ere near established road between 3200-5000 feet elevation. Six surveys, however, were above 7000 feet elevation. Surveys were conducted in each of the forest districts, but coverage was uneven, and the Sula and West Fork districts received less attention in 1995 than the Stevensville and Darby districts. Eight amphibian species (two salamanders, one toad, five frogs) have been reported from the Bitterroot National Forest; six of these species were encountered in 1995. Among amphibians, the Long-toed Salamander, Tailed Frog, Western Toad, and Spotted Frog were found throughout the forest, either during the 1995 survey or previously. Large gaps, however, remain in the distributions of each species. The Coeur d' Alene Salamander (a U.S. Federal Service Sensitive Species) and the Pacific Chorus Frog appear to have very restricted distributions within the forest (the Coeur d' Alene Salamander was not seen in 1995); the introduced Bullfrog appears restricted to sites near the Bitterroot River. The Northern Leopard Frog apparently has been extirpated from the Bitterroot National Forest area (and a large portion of western Montana). Nine reptile species (one turtle, two lizards, six snakes) have been reported on or near the Bitterroot National Forest; seven of these species were encountered in 1995. The Painted Turtle seems to be limited to the Bitterroot River area north of Hamilton. The Northern Alligator Lizard and Western Skink are widespread in western Montana, including on the BNF, but populations within their ranges appear to be disjunct; current population status of each is unknown and no skinks were reported in 1995. Rubber Boa, Gopher Snake, Western Terrestrial Garter Snake and Common Garter Snake are widespread, large gaps remain in the distributions of each species; the Gopher Snake seems to be most abundant in the Bitterroot Valley. Racer and Western Rattlesnake appear to be restricted to the east side of the Bitterroot Valley in drier sites; it is surprising that there are so few reports of Racers, and no rattlesnakes were reported in 1995. Only the Western Terrestrial Garter Snake could be considered as abundant and widespread.

Subjects

Genres

• Surveys