Monitoring and managing grass and forage biomass resources at the landscape level © 2013 Proceedings of the 22 nd International Grassland Congress 877 An efficient sampling protocol for sagebrush/grassland monitoring Larry L Larson A , Mounir Louhaichi B , Patrick E Clark C and Douglas E Johnson D A Department of Rangeland Ecology and Management, Oregon State University, Oregon, USA B International Center for Agricultural Research in the Dry Areas (ICARDA), Amman, Jordan C USDA/ARS, Boise, Idaho, USA D Department of Rangeland Ecology and Management, Oregon State University, Oregon, USA Contact email: llarson@eou.edu Keywords: Random sampling, digital photography, GPS unit, protocol. Introduction Rangeland scientists and quantitative ecologists have developed numerous methods and monitoring techniques that can be used for vegetation sampling (Barbour et al. 1987). The methods used to position samples (transects, quadrats, lines, and points) vary and can be classed as selective, capricious, systematic, or random. One of the prerequisites for valid statistical inference is that samples are taken randomly. A random sampling procedure implies that all elements or units of the population being studied have an equal chance of being represented in the sample. It also implies that selection of an element or unit does not influence the chance of other units being sampled. Data that is collected using random sampling procedures can be used to compare attributes of different populations or sites such as vegetative cover, density, production, growth rates, etc. This paper suggests a random sampling protocol that can be easily applied in the field for sagebrush/grassland monitoring. Material and Methods Our protocols typically employ a monopod or pole with a mounting head which allows us to point a digital camera vertically downward from a fixed height (Louhaichi et al. 2010). Also attached next to the camera is a continuously recording (1 Hz) WAAS enabled GPS unit (Fig. 1). This combination of instruments allows us to take high- resolution, vertical images from between 1.5 m and 5.0 m above the sample plot (Booth et al. 2004). The higher the camera, the larger the ground coverage and coarser the resolution. Advances in digital imaging technologies have compensated for the loss of resolution and modern cameras have sensors that can capture images with a pixel count of 5784 x 3861, which translates to a ground pixel resolution of 1mm for an image covering 5.78 by 3.86 m. The height, species list, and reference photos are completed in field using a pre-determined sampling pattern for each ecological site (Fig. 2 and 3). The data collection process can be divided into a series of steps in two operations: field (Fig. 4) and office (Fig. 5). Results and Discussion Since photographs can be taken quickly, many quadrats can be photographically sampled during a workday. It is not Figure 1. Digital charting apparatus. Figure 2. Landscape photo is taken (left) then reference photographs are taken of plants that are identifiable (right). Figure 3. Sampling pattern used within an ecological site. CORE Metadata, citation and similar papers at core.ac.uk Provided by University of Kentucky