The use of digital photos to assess visual cover for wildlife in rangelands

JOURNAL OF ENVIRONMENTAL MANAGEMENT

卷:91

Article

Carlyle, Cameron N.²  Fraser, Lauchlan H.¹  Haddow, Cindy M.³  Bings, Becky A.⁴  Harrower, William² 

[1] Thompson Rivers Univ, Dept Nat Resource Sci, Kamloops, BC V2C 5N3, Canada

[2] Univ British Columbia, Dept Bot, Vancouver, BC V6T 1X1, Canada

[3] Minist Environm, Environm Stewardship Div, Ecosyst Branch, Victoria, BC V8W 9M1, Canada

[4] Minist Environm, Williams Lake, BC V2G 4T1, Canada

关键词: Bunchgrass;    Digital image analysis;    Grazing;    Litter;    Range management;    Robel pole;    Wildlife management;   

DOI  :  10.1016/j.jenvman.2010.02.018

来源: Elsevier

【 摘 要 】

Grassland vegetation can provide visual cover for terrestrial vertebrates. The most commonly used method to assess visual cover is the Robel pole. We test the use of digital photography as a more accurate and repeatable method. We assessed the digital photography method on four forage grassland species (Pseudoroegneria spicata, Festuca campestris, Poa pratensis, Achnatherum richardsonii). Digital photos of 2-dimensional cutout silhouettes of three bird species sharp-tailed grouse, western meadowlark and savannah sparrow were used to model the impact of clipping (i.e., grazing) on visual cover. In addition, photos of artificial voles were used to model litter on cover available to small mammals. Nine sites were sampled and data were analyzed by the dominant grass species in each study plot. Regression analysis showed that digital photos (r(2) = 0.62) were a better predictor than the Robel pole (r(2) = 0.26) for assessment of cover. Clipping heights showed that clipping at less than 15 cm left the silhouettes 50% exposed. Digital photo analysis revealed that visual cover was affected by the type of grass species, with F. campestris > P pratensis > A. richardsonii > P. spicata. Biomass and litter were both positively related to cover for small mammals. (C) 2010 Elsevier Ltd. All rights reserved.

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