Rangeland Ecology & Management

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Digital Photography: Reduced Investigator Variation in Visual Obstruction Measurements for Southern Tallgrass Prairie
Author
Limb, Ryan F.
Hickman, Karen R.
Engle, David M.
Norland, Jack E.
Fuhlendorf, Samuel D.
Publisher
Society for Range Management
Publication Year
2007-09-01
Body

Landscapes with structural heterogeneity or patchiness can support diverse and stable wildlife populations. Visual obstruction methods (i.e., Robel pole and Nudd’s coverboard) are common and useful techniques for quantifying vegetation structure; however, both rely on ocular estimations, which can be highly variable between observers. Our objectives were to 1) compare measurement and observer variation for visual obstruction among the two standard methods and the digital image method we developed using a digital camera; and 2) compare the performance of the Robel pole and digital image to estimate standing crop. The mean variation across the five observers using the digital image method (6.8%) was significantly lower (P < 0.05) than both the Nudds’ coverboard (32.1%) and the Robel pole (52.2). There were no significant differences among locations for the digital image method; however, there were for both the Robel pole and Nudds’ cover board (P<0.05). The digital image method provided a better estimate of standing crop (r2 = 0.89) compared to the Robel pole (r2 = 0.68), accounting for 21% more of the observed variation in biomass. Long-term research programs that utilize seasonal field technicians to quantify habitat structure with a visual obstruction method could benefit from implementing use of the digital image method we developed. The low measurement error observed with this technique relative to the more traditional methods compared in this study might limit year- to-year and within-year variability of habitat structure data collected by numerous technicians with a high annual turnover.  The Rangeland Ecology & Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact lbry-journals@email.arizona.edu for further information. Migrated from OJS platform August 2020

Language
en
Resource Type
Text
Document Type
Journal Issue/Article
Digital Object Identifier (DOI)
10.2111/1551-5028(2007)60[548:DPRIVI]2.0.CO;2
Additional Information
Limb, R. F., Hickman, K. R., Engle, D. M., Norland, J. E., & Fuhlendorf, S. D. (2007). Digital photography: reduced investigator variation in visual obstruction measurements for southern tallgrass prairie. Rangeland Ecology & Management, 60(5), 548-552.
IISN
0022-409X
OAI Identifier
oai:repository.arizona.edu:10150/643192
Journal Volume
60
Journal Number
5
Journal Pages
548-552
Journal Name
Rangeland Ecology & Management
Keywords
biomass
sampling variation
techniques
wildlife habitats