Capture data for Ringed Salamanders in east-central Missouri (2010)

Objective: The primary objective of this study was to determine the most important variable(s) influencing breeding wetland use by Ringed Salamanders in east-central Missouri, which can subsequently be incorporated into conservation recommendations for this imperiled species. <br>Methods: To determine Ringed Salamander occupancy of potential breeding wetlands, we sampled a total of 38 wetlands during the fall 2010 breeding season (September–October) in east-central Missouri (U.S.A.; 38.6878, –90.7492). Each wetland was sampled for three consecutive nights with six - eight double-throated minnow traps. We identified all amphibians to species and recorded total numbers for each species captured; all animals were then released at the site of capture. For each wetland location, data were collected on four site covariates: (1) FISH – presence/absence of predatory fish; (2) LEAF – leaf litter depth (mm); (3) COV – canopy cover (%); and (4) BUFFER – minimum amount of forest cover between the wetland and an open area. To determine whether a site contained predatory fish, we recorded when fish were captured in the minnow traps used for amphibian sampling. Leaf litter depth and canopy cover were measured at four equidistant points around the wetland (approximately 1 m from the wetland edge) and the four values were then averaged. Leaf litter depth was measured with a hand ruler and canopy cover measurements were taken with a densiometer. To calculate the minimum buffer distance for each wetland, a GPS waypoint was taken at each wetland and subsequently plotted using ArcGIS 10.0 (ESRI, Redlands, CA). The distance between the wetland and nearest open area (agricultural field, paved road, etc.) was then measured. Data layers for land use/land cover were obtained from the Missouri Spatial Data Information Service (http://msdis.missouri.edu/index.htm). Additionally, data were collected on three sampling covariates: (1) PRECIP – amount of precipitation in the 24 hr preceding sampling; (2) AVGTEMP – average temperature in the 24 hr preceding sampling; and (3) TIME – day of survey. Temperature and rainfall data were obtained from the National Climatic Data Center (http://www.ncdc.noaa.gov). This research was conducted under MDC permit #14468. This project conformed to the legal requirements for the use of vertebrates in research and animal care methods followed protocols from Guidelines for Use of Live Amphibians and Reptiles in Field Research compiled by ASIH, HL, and SSAR (document can be accessed at: http://www.aaalac.org/accreditation/Guidelines_for_Use_of_Live_Amphibians_and_Reptiles.pdf).研究目标：本研究的核心目标为明确美国密苏里州中东部环纹钝口螈（Ringed Salamander）繁殖湿地选择的关键影响因子，所得结果可为该濒危物种种群的保护建议提供科学支撑。 方法：为探明环纹钝口螈对潜在繁殖湿地的占用情况，研究团队于2010年秋季（9—10月）在密苏里州中东部（美国；地理坐标38.6878, –90.7492）的38处潜在繁殖湿地开展野外采样工作。每处湿地连续三个夜间使用6~8口双开口小型捕鱼陷阱（double-throated minnow traps）进行采样。对捕获的所有两栖动物进行物种鉴定，并记录各物种的总捕获量，随后将所有捕获动物于捕获原地释放。 针对每处湿地，我们收集了四类场地协变量数据：（1）FISH：捕食性鱼类的存在/缺失状态；（2）LEAF：枯落物厚度（单位：毫米）；（3）COV：林冠盖度（百分比）；（4）BUFFER：湿地与开阔区域之间的最小森林覆盖距离。判断湿地内是否存在捕食性鱼类时，我们通过两栖动物采样所用捕鱼陷阱的捕获记录进行确认。枯落物厚度与林冠盖度的测量点位设置在湿地周边距岸线约1米处的4个等距点，随后对4组测量值取平均值。枯落物厚度采用手持直尺测量，林冠盖度则通过冠层密度计（densiometer）测定。 为计算每处湿地的最小缓冲距离，我们在每处湿地设置GPS航点，随后通过ArcGIS 10.0（ESRI，美国加利福尼亚州雷德兰兹市）进行空间绘图，并测量湿地与最近开阔区域（农田、铺装道路等）之间的直线距离。土地利用/土地覆盖数据图层取自密苏里州空间数据信息服务中心（Missouri Spatial Data Information Service，http://msdis.missouri.edu/index.htm）。 此外，我们还收集了三类采样协变量数据：（1）PRECIP：采样前24小时的累积降水量；（2）AVGTEMP：采样前24小时的平均气温；（3）TIME：调查当日日期。气温与降水数据取自美国国家气候数据中心（National Climatic Data Center，http://www.ncdc.noaa.gov）。 本研究获得密苏里州保护部（Missouri Department of Conservation，MDC）许可#14468。本项目严格遵循脊椎动物研究的相关法律要求，实验动物的饲养与操作均符合由ASIH、HL及SSAR学会联合编制的《野外研究活体两栖爬行动物使用指南》（可通过http://www.aaalac.org/accreditation/Guidelines_for_Use_of_Live_Amphibians_and_Reptiles.pdf获取）中的相关规程。