San Diego Management & Monitoring Program


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2022 Southern California Whiptail Guide fact sheet

Lead author: Gregory B. Pauly

2022 Hidden in Plain Sight: Detecting Invasive Species When They Are Morphologically Similar to Native Species journal article

Lead author: Samuel R. Fisher
Early detection and rapid response (EDRR) can help mitigate and control invasive species outbreaks early on but its success is dependent on accurate identification of invasive species. We evaluated a novel outbreak in San Diego County, California of the Sonoran Spotted Whiptail (Aspidoscelis sonorae) in order to confirm their spread as well as quantify how to better detect and potentially manage this invasive species in California. We found that A. sonorae went undetected for over two years due to its morphological similarity to native whiptails and that it has spread rapidly since they were first observed. There are two species of native California whiptails with which A. sonorae can be confused locally, the Orange-throated Whiptail (Aspidoscelis hyperythrus), and to a lesser extent the Tiger Whiptail (Aspidoscelis tigris). We review key diagnostic features to distinguish A. sonorae from native California whiptails. We also discuss how to efficiently use widely available community science tools to rapidly assess a novel invasive species outbreak and outline suggestions to help manage cryptic invasive species.

2003 Sampling Design Optimization and Establishment of Baselines for Herpetofauna Arrays at the Point Loma Ecological Reserve report

Lead author: Andrea Atkinson
Only 12 of the original 19 species thought to be present at Point Loma Ecological Reserve were detected during pitfall trap sampling from 1995-2001 (see Table14) and only 11 during the actual time period used in this analysis (1996-2000). Monitoring for declines in species still present at Point Loma is necessary to provide information for timely management intervention. Striped racer captures and number of species detected per array declined from 1996 to 2000. While striped racer declines could be caused by the snakes learning to avoid the traps, the decline is a concern and should be monitored. Declines in the number of juvenile striped racers would be especially important to track, since they will not yet have learned to avoid the traps. The following recommendations are made for refining monitoring for herpetofauna using pitfall trap arrays at Point Loma Ecological Reserve at Point Loma, California. Refinements should provide some reduction in sampling effort while maintaining an ability to detect approximately a 20% drop in the number of species detected per array, a 40-50% drop in orange-throated whiptail (Cnemidophorus hyperythrus) capture rates, and an ability to continue monitoring trends in striped racer (Masticophis lateralis), ring-necked snake (Diadophis punctatus), and southern Pacific rattlesnake (Crotalus viridis), which were variables requested by the reserve manager. - The number of sampling days per year could be reduced from 50 to 40. - Only arrays #6 and #12 should be discontinued. - Control limits were calculated for the various response variables (see Table 15 for a summary of all control limits). - The 40 sampling days per year could be distributed across five 8-day sampling periods (similar to the original design of five 10-day sample periods) or alternatively across ten 4-day sampling periods with little effect on the results, provided they occur at approximately the same time during the year as the baseline data. This should allow work to be scheduled within a single work-week. - If further reductions in sampling are required due to budget considerations, sampling the 15 arrays every other year is preferred to reducing the number of arrays sampled. In addition, it may be possible to reduce sampling in the January-February sampling period to only 4 days if tracking declines in salamanders is not a concern. Sampling in January- February should be timed after rain events to maximize detection of salamande

2004 Barnett Ranch Open Space Preserve Biological Resources Report report

This biological resources report was prepared for the County of San Diego (County) in order to provide information on baseline biological conditions prior to the Cedar Fire of 2003 and to assist in the formation of Area Specific Management Directives (ASMDs) for the Barnett Ranch Open Space Preserve (Preserve) on the approximately 728-acre Barnett Ranch located in the unincorporated Ramona Community Planning Area of central San Diego County east of State Route (SR) 67 and south of SR 78. The project site supports 16 vegetation communities: southern coast live oak riparian forest, southern willow scrub, freshwater seep, riparian scrub, open water, open Engelmann oak woodland, coast live oak woodland, wildflower field, Diegan coastal sage scrub (including disturbed), coastal sage-chaparral scrub, southern mixed chaparral, non-native grassland, eucalyptus woodland, extensive agriculture, disturbed habitat, and developed land. No federally or state listed threatened or endangered plant species were observed on site; however, one plant species of federal special concern was observed: felt-leaved monardella (Monardella hypoleuca ssp. lanata). In addition, four plant species recognized as sensitive by the California Native Plant Society and/or the County were observed: delicate clarkia (Clarkia delicata), San Diego County viguiera (Viguiera laciniata), Engelmann oak (Quercus engelmannii), and ashy-spike moss (Selaginella cinerascens). No animal species listed as threatened or endangered by the U.S. Fish and Wildlife Service (USFWS) or California Department of Fish and Game were observed on the site; however, 10 animals observed on site are federal species of concern: orange-throated whiptail (Cnemidophorus hyperythrus beldingi), coastal whiptail (Cnemidophorus tigris stejnegeri), coastal rosy boa (Lichanura trivirgata roseofusca), southern California rufous-crowned sparrow (Aimophila ruficeps canescens), loggerhead shrike (Lanius ludovicianus), California thrasher (Toxostoma redivivum), white-tailed kite (Elanus leucurus), Costa's hummingbird (Calypte costae), lark sparrow (Chondestes grammacus), and Pacific slope flycatcher (Empidonax difficilis). Ten animals observed on site are California species of special concern: silvery legless lizard (Anniella pulchra pulchra), prairie falcon (Falco mexicanus), northern red-diamond rattlesnake (Crotalus exsul), golden eagle (Aquila chrysaetos), Cooper's hawk (Accipiter cooperi), sharpshinned