Anthony R. Olsen

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The spatial distribution of a natural resource is an important consideration in designing an efŽ cient survey or monitoring program for the resource. Generally, sample sites that are spatially balanced, that is, more or less evenly dispersed over the extent of the resource, are more efŽ cient than simple random sampling. We review a uniŽ ed strategy for(More)
Sampling of a population is frequently required to understand trends and patterns in natural resource management because financial and time constraints preclude a complete census. A rigorous probability-based survey design specifies where to sample so that inferences from the sample apply to the entire population. Probability survey designs should be used(More)
An unequal probability design was used to develop national estimates for 268 persistent, bioaccumulative, and toxic chemicals in fish tissue from lakes and reservoirs of the conterminous United States (excluding the Laurentian Great Lakes and Great Salt Lake). Predator (fillet) and bottom-dweller (whole body) composites were collected from 500 lakes(More)
The regional-scale importance of an aquatic stressor depends both on its regional extent (i.e., how widespread it is) and on the severity of its effects in ecosystems where it is found. Sample surveys, such as those developed by the U.S. Environmental Protection Agency's Environmental Monitoring and Assessment Program (EMAP), are designed to estimate and(More)
Accurate characterization of wetland condition at a regional or watershed scale requires an assessment that includes both a quantity and quality component. A probabilistic sampling design can facilitate the implementation of such assessments through its ability to extrapolate results from a random sample of wetlands to the entire population of wetlands over(More)
Benthic macrofaunal sampling protocols in the U.S. Environmental Protection Agency's Environmental Monitoring and Assessment Program (EMAP) are to collect 30 to 50 random benthic macrofauna [defined as animals retained on a 0.5 mm (East and Gulf Coasts, USA) or a 1.0 mm mesh sieve (West Coast, USA)] samples per reporting unit using a 0.044 m(2) (East and(More)
The spatial distribution of a natural resource is an important consideration in designing an efficient survey or monitoring program for the resource. We review a unified strategy for designing probability samples of discrete, finite resource populations, such as lakes within some geographical region; linear populations, such as a stream network in a(More)
For landscapes that are cast as categorical raster maps, we present an entropy based method for obtaining a multiresolution characterization of spatial pattern. The result is a conditional entropy profile which reflects the rate of information loss as map resolution is degraded by increasing the pixel size 1 through a resampling filter. We choose a random(More)
Multiple agencies in the Pacific Northwest monitor the condition of stream networks or their watersheds. Some agencies use a stream ‘‘network’’ perspective to report on the fraction or length of the network that either meets or violates particular criteria. Other agencies use a ‘‘watershed’’ perspective to report on the health or condition of watersheds.(More)
This article is closely related to papers by Carr et al (1998a, 1998b). The first paper provides a general description of linked micromap (LM) plots such as that in Figure 1b. The second paper puts LM plots to work in describing Omernik Level II ecoregions. It also promotes LM plots as useful methodology in the KDD pattern discover process and as overviews(More)