Small Terrestrial Vertebrates - San Diego Co. [ds90]

Pitfall sampling for small vertebrates in San Diego County conducted by the USGS as part of the Multiple Species Conservation Plan (MSCP). The dataset contains spatial and temporal information on animal captures. Dataset includes capture records from April 1995 to May 2004. Accuracy of individual data fields have been reviewed and data collection efforts are ongoing. METHODS Array Design: The array design consists of three 15-meter arms of drift fence with 7 pitfall traps and 3 funnel traps. One pitfall trap is placed in the center of the array with each of the 3 arms of drift fence extending outward from the center trap. The angle formed by the array arms around the center trap can vary but should be approximately 120 degrees. Pitfall traps are placed in the middle and at the end of each arm of fencing. One funnel trap is placed along each arm approximately halfway between the middle and end pitfall traps on the right side of each arm when looking from the center trap toward the end trap. The funnel traps are placed consistently on the same side of the fence of each array to ensure that funnel trapping results are comparable from array to array. Trap Labeling/Numbering: For identification purposes, each array at a given study site is assigned a number. Each array arm is assigned a number 1, 2, and 3 in a clockwise direction beginning with the arm arbitrarily designated as arm number 1 (usually the arm first encountered on the trail is assigned the number 1). The pitfall containers are labeled A, B, and C for outer, middle, and center buckets, respectively. All of the traps making up an array are first identified by the number of the array followed by the number of the arm along which the container lies. For example, the middle container of arm three, at array five, would be identified as 5-3B. The center container of array five would be identified as simply 5-C. The funnel traps are identified by the arm number along which they lay, 1-3. For example, the funnel trap located along arm two of array five would be identified as 5-2S. Survey Methods: In our protocol, traps at any given study site are sampled for 4 consecutive days and then closed (i.e., opened on Monday, sampled daily Tuesday through Friday, closed Friday). This is referred to as a sample period. Sample periods are scheduled every 4 to 5 weeks for a given site, resulting in 10 to 12 sample periods a year. This sampling schedule allows for the collection of target information, including seasonal activity patterns of reptiles and amphibians. Based on our analysis of species accumulation curves, it is recommended that a site be sampled 3 to 5 consecutive years to increase the probability of detecting rare species. But this also depends upon the number of trapping arrays at any chosen site. We usually place arrays in multiple representative habitats within a site and include replicates within habitat types as funding permits.

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Use restricted to government agencies. Positional accuracy of individual locations is limited by: accuracy of satellite GPS locations, observer error, and possible data entry errors. Although, all reasonable attempts have been made to limit these factors, positional accuracy for any individual point should not necessarily be considered minimal. The appropriateness of multiple scales of inference, is the end-users responsibility to justify and the originators assume no responsibility for incorrect or misleading uses of this data