Knowledge Resource Center for Ecological Environment in Arid Area
DOI | 10.2307/3802929 |
Distance sampling for Sonoran Desert tortoises | |
Swann, DE; Averill-Murray, RC; Schwalbe, CR | |
通讯作者 | Swann, DE |
来源期刊 | JOURNAL OF WILDLIFE MANAGEMENT
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ISSN | 0022-541X |
EISSN | 1937-2817 |
出版年 | 2002 |
卷号 | 66期号:4页码:969-975 |
英文摘要 | We used line transects and distance sampling in combination with radiotelemetry to estimate density of a desert tortoise (Gopherus agassizii) population in the Rincon Mountains near Tucson, Arizona, USA, as part of a long. term study evaluating the impact of urban development on tortoises. During 2000, 34 I-km transects were each sampled twice in the 368.5-ha study area. We observed 46 tortoises with midline carapace lengths greater than or equal to 150 mm (subadults and adults) plus 7 juveniles on transects. For subadults and adults, the encounter rate was 0.63 tortoises/km, and the mean proportion of tortoises observable during radiotelemetry, conducted concurrently with transect sampling, was 82%. Corrected mean density based on line transects and radiotelemetry was 0.523 tortoises/ha (CV = 22.99, 95% CI = 0.29-0.79), and absolute abundance in the study area was estimated to be 193 (CV = 23.0%, CI = 107-291). Using the 2 independent coverages of transects as separate samples, the Lincoln-Petersen mark-recapture estimator produced an abundance estimate of 224 subadult and adult tortoises (CV = 53.9%, CI = 72-440). Transects measured on the ground over uneven topography resulted in 3% smaller estimates of density when compared to analysis with transect lengths determined from coordinates plotted on a map. Distance sampling appears to be a feasible method of estimating density of Sonoran Desert populations of the desert tortoise, but transect lengths should be based on mapped rather than measured distances to prevent biases caused by uneven topography. |
英文关键词 | abundance estimation Arizona density estimation desert tortoise distance sampling Gopherus agassizii line transect radiotelemetry Sonoran Desert |
类型 | Article |
语种 | 英语 |
国家 | USA |
收录类别 | SCI-E |
WOS记录号 | WOS:000179706800004 |
WOS关键词 | DENSITY |
WOS类目 | Ecology ; Zoology |
WOS研究方向 | Environmental Sciences & Ecology ; Zoology |
来源机构 | University of Arizona ; United States Geological Survey |
资源类型 | 期刊论文 |
条目标识符 | http://119.78.100.177/qdio/handle/2XILL650/143331 |
作者单位 | (1)Saguaro Natl Pk, Tucson, AZ 85730 USA;(2)Arizona Game & Fish Dept, Phoenix, AZ 85023 USA;(3)Univ Arizona, US Geol Survey, Sonoran Desert Field Stn, Tucson, AZ 85721 USA |
推荐引用方式 GB/T 7714 | Swann, DE,Averill-Murray, RC,Schwalbe, CR. Distance sampling for Sonoran Desert tortoises[J]. University of Arizona, United States Geological Survey,2002,66(4):969-975. |
APA | Swann, DE,Averill-Murray, RC,&Schwalbe, CR.(2002).Distance sampling for Sonoran Desert tortoises.JOURNAL OF WILDLIFE MANAGEMENT,66(4),969-975. |
MLA | Swann, DE,et al."Distance sampling for Sonoran Desert tortoises".JOURNAL OF WILDLIFE MANAGEMENT 66.4(2002):969-975. |
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