2.3 Response design
2.3.2 Choosing an appropriate response design
Introduction Choosing Results and next steps
In many ways the the process of developing your response design is similar to selecting tools from a toolbox. There are many tools to choose from but some work better for the job at hand than others. Developing an appropriate response design to meet your objectives will depend on a variety of factors including your attributes of interest and how well you can measure or estimate them given costs of making the measurements relative to your budget. In some cases standard methods or guidelines that can be adapted to your needs are available. Most field operations manuals describe what and how your attributes will be measured or collected. These protocols describe the reach scale layout for measurements (i.e., the length of reach to be sampled, whether a habitat based or transect based approach is used, how many measurements will be made at the site). The protocols also describe the temporal pattern of sampling as in the case where your metric calculation requires data from repeated visits to the site. Also, in many cases, sampling must occur during an “index” window because all sites cannot be sampled simultaneously. In these cases, it is useful to sample some sites more than once to estimate this “index window” component of variation. An index window should be chosen so that:
- It is as short as possible within field operational constraints,
- The variation in the measurements is as small as possible within the window, and
- It is ecologically based.
The procedures used to calculate the metrics from the measurements comprise an analytical component of a response design. In some cases, the metric of interest might come directly from the measurement, e.g., maximum temperature during the June – Aug. interval (no calculation needed, except to read logger’s maximum temperature). In most cases, a set of measurements is combined to calculate the metric of interest for each site in the sample. For example, an area-under-the-curve method is used to calculate the number of spawning salmon from the measurements taken during each of many visits to the site. Alternatively, the mean width of a stream is calculated from a set of width measurements taken at many locations across the stream’s “plot” (e.g., mean of 10 width measurements taken systematically across 500 meters centered on the site, or 40 times the wetted channel width). Some metrics require complex calculations derived from measurements of a variety of attributes at a site. Documentation of these aspects of data collection and metric calculation should be part of your response design.
The following references illustrate how various programs have developed and documented their response designs. They may provide useful prototypes for developing response designs specific to you monitoring needs.
- Oregon Adult Salmonid Inventory and Sampling (OASIS) Project. 2009. Coastal salmon spawning survey procedures manual. Oregon Department of Fish and Wildlife.
- Johnson. D.H., B.M. Shrier, J.S. O’Neal, J.A. Knutzen, X. Augerot, T.A. O’Neil, and T.N. Pearson. 2007. The Salmonid Field Protocol Handbook, Techniques for assessing status and trends in salmon and trout populations. American Fisheries Society in association with State of the Salmon. Bethesda, Maryland ISBN-13: 978-1-888569-92-6. 478 pages.
- Oakley, K.L., Thomas, L.P. and Fancy, S.G. 2003. Guidelines for long term monitoring protocols. Wildlife Society Bulletin, 31(4):1000-1003)
- Peck, D. V., Herlihy, A. T., Hill, B. H., Hughes, R. M., Kaufmann, P. R., Klemm, D.J., Lazorchak, J. M., McCormick, F. H., Peterson, S. A., Ringold, P. L., Magee, T. & Cappaert, M. R.. 2005. Environmental Monitoring and Assessment Program - Surface Waters Western Pilot Study: Field Operations Manual for Wadeable Streams. EPA Report EPA 600/R-05/xxx, U.S. Environmental Protection Agency, Office of Research and Development, Washington, DC.
- Stevens, Jr. D.L., and N.S. Urquhart. 2000. Response Designs and Support Regions in Sampling Continuous Domains. Environmetrics 11:13-42.
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