Spatially Balanced Sampling of Natural Resources

Stevens, Donald L.; Olsen, Anthony R.

doi:10.1198/016214504000000250

Cited by 1,032 publications

(879 citation statements)

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“…Alternatively, background values may be estimated using samples from a random or probability-based design [26]. Such samples include all waters within the sampling frame, including impaired sites.…”

Section: Background Estimationmentioning

confidence: 99%

A method for deriving water‐quality benchmarks using field data

Cormier

Suter

2012

Enviro Toxic and Chemistry

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Abstract-The authors describe a methodology that characterizes effects to individual genera observed in the field and estimate the concentration at which 5% of genera are adversely affected. Ionic strength, measured as specific conductance, is used to illustrate the methodology. Assuming some resilience in the population, 95% of the genera are afforded protection. The authors selected an unambiguous effect, the presence or absence of a genus from sampling locations. The absence of a genus, extirpation, is operationally defined as the point above which only 5% of the observations of a genus occurs. The concentrations that cause extirpation of each genus are rank-ordered from least to greatest, and the benchmark is estimated at the 5th percentile of the distribution using two-point interpolation. When a full range of exposures and many taxa are included in the model of taxonomic sensitivity, the model broadly characterizes how species in general respond to a concentration gradient of the causal agent. This recognized U.S. Environmental Protection Agency methodology has many advantages. Observations from field studies include the full range of conditions, effects, species, and interactions that occur in the environment and can be used to model some causal relationships that laboratory studies cannot. Environ. Toxicol. Chem. 2013;32:255-262. # 2012 SETAC

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Section: Background Estimationmentioning

confidence: 99%

A method for deriving water‐quality benchmarks using field data

Cormier

Suter

2012

Enviro Toxic and Chemistry

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“…The approach of Voronoi polygons, suggested by Stevens & Olsen (2004), is used to compare spatial balance. We assume that n = ∑ N i=1 π i is a positive integer.…”

Section: Simulation Studiesmentioning

confidence: 99%

“…21-22) to produce unequal probability samples that are well spread over the population. This idea was generalized to two dimensions by Stevens & Olsen (2004) who introduced the Generalized Random-Tessellation Stratified (GRTS) design. The idea behind GRTS is to map the two-dimensional locations into one dimension while preserving some spatial order.…”

Section: Introductionmentioning

confidence: 99%

Spatially correlated Poisson sampling

Grafström

2012

Journal of Statistical Planning and Inference

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A new method for sampling from a finite population that is spread in one, two or more dimensions is presented. Weights are used to create strong negative correlations between the inclusion indicators of nearby units. The method can be used to produce unequal probability samples that are well spread over the population in every dimension, without any spatial stratification. Since the method is very general there are numerous possible applications, especially in sampling of natural resources where spatially balanced sampling has proven to be efficient. Two examples show that the method gives better estimates than other commonly used designs.

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“…The sampling sites were defined according to the concept of spatially balanced sampling (Stevens & Olsen 2004) adapted to large reservoirs (Macedo et al 2014). The reservoir's perimeter was divided into 40 equidistant sections based on a randomly defined first point.…”

Section: Study Areamentioning

confidence: 99%

Ecological assessment of a southeastern Brazil reservoir

et al. 2015

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Reservoirs are artificial ecosystems with multiple functions having direct and indirect benefits to humans; however, they also cause ecological changes and influence the composition and structure of aquatic biota. Our objectives were to: (1) assess the environmental condition of Nova Ponte Reservoir, Minas Gerais state, southeastern Brazil; and (2) determine how the aquatic biota respond to disturbances. A total of 40 sites in the littoral zone of the reservoir were sampled to characterize physical and chemical habitat, land use, and benthic macroinvertebrate and fish assemblages. The predominant type of land cover near the reservoir was natural vegetation. A total of 29 fish species and 39 macroinvertebrate taxa were collected, including eight alien species. Most sites had intermediate levels of human disturbance, however, high levels of degradation were associated with high proportions of alien species. Disturbances at multiple scales may alter natural patterns and processes, leading to environmental changes and damaging biological communities. Our results reinforce the importance of assessing reservoir ecological conditions at several scales. The study of land use, littoral zone physical habitat characteristics, water quality, and assemblage structure set the ground for proposing actions to rehabilitate and conserve aquatic ecosystems. Keywords: reservoirs, water quality, bioindicators, physical habitat, environmental quality.MARTINS, I., SANCHES, B., KAUFMANN, P.R., HUGHES, R.M., SANTOS, G.B., MOLOZZI, J., CALLISTO, M. Avaliação Ecológica de um reservatório no sudeste do Brasil.http://dx.doi.org/10.1590/1676-06032015006114Resumo: Reservató rios sã o ecossistemas artificiais com mú ltiplas funçõ es e que oferecem benefícios diretos e indiretos ao homem; no entanto, também causam mudanças ecoló gicas e influenciam a composiçã o e estrutura da biota aquá tica. Os objetivos deste estudo foram: (1) avaliar a condição ambiental do reservató rio de Nova Ponte, Estado de Minas Gerais, sudeste do Brasil; e (2) verificar se a biota aquá tica responde aos distú rbios. No total, 40 sítios amostrais na regiã o litorâ nea do reservató rio foram amostrados para caracterizar os habitats físicos e químicos, cobertura e uso do solo, assembleias de macroinvertebrados e peixes. Vegetaçã o natural de cerrado foi o tipo predominante de cobertura do solo no entorno do reservató rio. 29 espécies de peixes e 39 taxa de macroinvertebrados bentô nicos foram coletadas, incluindo oito espécies exó ticas. A maioria dos sítios amostrais possui níveis intermediá rios de distú rbio antró pico, porém o aumento de alteraçõ es antró picas foi associado ao aumento do nú mero e abundâ ncia de espécies exó ticas. Distú rbios em mú ltiplas escalas podem alterar os padrõ es e processos naturais, levando a mudanças ambientais e nas comunidades bioló gicas. Nossos resultados reforçam a importâ ncia de avaliar as condiçõ es ecoló gicas do reservató rio em vá rias escalas. O estudo do uso e cobertura do solo, características de habitats físic...

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Spatially Balanced Sampling of Natural Resources

Cited by 1,032 publications

References 27 publications

A method for deriving water‐quality benchmarks using field data

A method for deriving water‐quality benchmarks using field data

Spatially correlated Poisson sampling

Ecological assessment of a southeastern Brazil reservoir

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