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Abstract
To improve surveys of sparse objects, methods that use auxiliary information have been suggested. Guided transect sampling uses prior information, e.g., from aerial photographs, for the layout of survey strips. Instead of being laid out straight, the strips will wind between potentially more interesting areas. 3P sampling (probability proportional to prediction) uses information not available prior to the survey (e.g., the quality of downed logs), for selection of substrates for species inventories. Then, the surveyor's judgments of the substrates' suitability for the species of interest are used as the base for selection. Initial studies have shown that these methods have a potential to improve the efficiency of surveys of sparse populations.
Parent Publication
Citation
Ringvall, Anna. 2007. New methods for sampling sparse populations. In: McRoberts, Ronald E.; Reams, Gregory A.; Van Deusen, Paul C.; McWilliams, William H., eds. Proceedings of the seventh annual forest inventory and analysis symposium; October 3-6, 2005; Portland, ME. Gen. Tech. Rep. WO-77. Washington, DC: U.S. Department of Agriculture, Forest Service: 215-220.
