Two-Dimensional Systematic Sampling of Land Use

Dunn, Richard; Harrison, Andrew R.

doi:10.2307/2986177

Cited by 77 publications

(41 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Cochran ( 1946, see also Iachan 1982 analytically proved that a systematic design is more precise for linear populations whose spatial autocorrelation declines exponentially with separation distance. Examples of systematic designs bringing higher survey precision in spatially autocorrelated populations were reported in a range of applied ecological contexts (e.g., Dunn and Harrison 1993, Ambrosio et al 2004, Aune-Lundberg and Strand 2014 and in the application of Euclidean distance analysis to animal habitat selection analysis (Benson 2013 ) and in stereology (Gundersen et al 1999 ).…”

Section: True Precision Of Random and Systematic Survey Designsmentioning

confidence: 99%

“…More recent statistical investigation (D ' Orazio 2003, Wolter 2007 ) assumed systematic sampling to be more precise in autocorrelated populations and focused on the still unsolved problem of how to reliably estimate the variance of the estimate of the mean from a systematic survey for linear (Wolter 1984(Wolter , 2007 and two-dimensional (i.e., spatial) populations (D ' Orazio 2003 ). Published studies in the applied ecological literature have now shifted to general agreement that systematic designs are more precise in spatially autocorrelated populations (e.g., Dunn and Harrison 1993, Ambrosio et al 2004, Aune-Lundberg and Strand 2014.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Precision of systematic and random sampling in clustered populations: habitat patches and aggregating organisms

McGarvey¹,

Burch²,

Matthews³

2015

Ecological Applications

View full text Add to dashboard Cite

Section: True Precision Of Random and Systematic Survey Designsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Precision of systematic and random sampling in clustered populations: habitat patches and aggregating organisms

McGarvey¹,

Burch²,

Matthews³

2015

Ecological Applications

View full text Add to dashboard Cite

“…32). Dunn & Harrison (1993) used a similar variance estimator in a simulation study and showed that it outperformed the random sample variance estimator (Eq. 1).…”

Section: Discussionmentioning

confidence: 99%

“…Milne (1959) and Ripley (1981) suggest that treating the sample as random remains a reasonable approach, and that the usual variance estimator u provides satisfactory performance. However, Payandeh (1970) and Dunn & Harrison (1993) caution that this approach can seriously overestimate the sampling error and that a systematic sample variance estimator should be used.…”

Section: Discussionmentioning

confidence: 99%

Abundance of large toheroa (Paphies ventricosaGray) at Oreti Beach, 1971–90, estimated from two‐dimensional systematic samples

Millar

Olsen

1995

New Zealand Journal of Marine and Freshwater Research

View full text Add to dashboard Cite

The population of toheroa (Paphies ventricosa Gray) at Oreti Beach, South Island, New Zealand, was until recently considered relatively minor in comparison to those of the North Island west coast beaches. It is now the sole remaining toheroa population in New Zealand to support recreational toheroa gathering. This paper analyses count data from 22 systematic surveys of large toheroa (> 8 cm) at Oreti Beach between 1971 and 1990. A variance estimator appropriate to two-dimensional systematic surveys is developed to enable computation of confidence intervals for these abundance estimates. It is concluded that the recreational harvest taken during open days can not be reliably estimated by pre-and post-harvest surveys and should instead be determined from inspection and enumeration of open day participants. At current population and harvest levels the impact of occasional open days at Oreti Beach is slight; however, the high annual variability of toheroa populations and the uniqueness of this one remaining harvestable stock suggest a need for continued population surveys.

show abstract

“…Variances were calculated using a systematic sampling variance estimator described by Millar & Olsen (1995). Simple random sampling variance can overestimate the sampling error in systematic surveys (Dunn & Harrison 1993), because the quadrat position is not random, but is directly related to the position of the first quadrat.…”

Section: Population Estimatesmentioning

confidence: 99%

Effects of beach erosion on abundance and distribution of toheroa(Paphies ventricosa)at Bluecliffs Beach, Southland, New Zealand

Beentjes¹,

Carbines

Willsman

2006

New Zealand Journal of Marine and Freshwater Research

View full text Add to dashboard Cite

Data on abundance, distribution, and size structure of toheroa (Paphies ventricosa) on Bluecliffs Beach, Southland, New Zealand from 42 surveys (1966 to 2005) are presented. Toheroa abundance declined from over 2 million adults in the mid 1960s to c. 80000 by 1990 and since then has remained low but relatively stable. The decline mirrors that of other toheroa populations throughout New Zealand. Recent recruitment was highly variable but low compared with historical levels in the 1960s. Length frequency distributions are characteristically bimodal with a strong adult mode and a juvenile mode of variable strength, with relatively few toheroa of intermediate size. The distribution is related to mortality and growth characteristics of Bluecliffs Beach toheroa. Spatial distribution of adult toheroa has progressively changed over the last 40 years-historical distribution included the entire beach and toheroa were most dense just east of the Rowallan Burn. Since 1997, they have been aggregated into one large bed just west of the Rowallan Burn. Toheroa showed intertidal size zonation with small juveniles near high water and larger toheroa near mid to low water. from the beach between 1997 and 2005, exposing underlying gravel and cobble substrates, and a general erosion of the vegetated dunes. Aerial photos from 1947 reveal that Bluecliffs Beach was homogeneous sand substrate-significant erosion and loss of sand began in the mid 1980s and only c. 54% of the beach surface is now fine/coarse sand. Our results indicate that distribution and abundance of toheroa on Bluecliffs Beach is related to the amount and distribution of sand on the beach. If the erosion continues with loss of sand habitat, the toheroa population may be at risk of collapsing.

show abstract

Two-Dimensional Systematic Sampling of Land Use

Cited by 77 publications

References 16 publications

Precision of systematic and random sampling in clustered populations: habitat patches and aggregating organisms

Precision of systematic and random sampling in clustered populations: habitat patches and aggregating organisms

Abundance of large toheroa (Paphies ventricosaGray) at Oreti Beach, 1971–90, estimated from two‐dimensional systematic samples

Effects of beach erosion on abundance and distribution of toheroa(Paphies ventricosa)at Bluecliffs Beach, Southland, New Zealand

Contact Info

Product

Resources

About