Document Type
Report
Publication Date
12-2011
Pages
52 pp.
Abstract
The primary objective of this project was to develop an analytical tool that management could use to assess the ecological value of the benthos for higher trophic levels. Ideally any tool developed should be simple to implement, adaptable to both fixed and probability monitoring programs and applicable across multiple spatial and temporal scales. Direct evaluations of secondary productivity involve time-consuming cohort or size-based methods that require multiple measurements of the populations in question over time (Dolbeth et al., 2005; Cusson and Bourget, 2005). However, empirical regression models have been developed that provide reasonable alternatives to these techniques when direct measurements are not an option (e.g Schwinghamer et al., 1986; Edgar, 1990; Tumbiolo and Downing, 1994; Brey, 1999; Brey, 2001). These relationships incorporate benthic population metrics biomass, abundance, mean individual weights, etc.), environmental metrics (temperature, water depth), and taxon-specific metrics to adjust for body-size dependent turn-over rates to estimate production rates (or P/B ratios can be used to obtain production rates). Of the available empirical relationships we evaluated two approaches to calculate benthic secondary production in Chesapeake Bay – those of Edgar (1990) and Brey (2001) described in detail in the Methods section. Edgar’s (1990) equation was selected because it has been used in several other studies conducted in Chesapeake Bay (Diaz and Schaffner 1990) and elsewhere (Wilbur and Clarke, 1998; Gillet, 2011; Kersey, 2011). Brey’s (2001) equation was selected because it incorporates variation related not only to temperature but also to sample depth and to effects relating to taxonomic composition that were not incorporated into Edgar’s model and because comparisons of different empirical models found that Brey’s model generally performed better than others (Dolbeth et al., 2005; Cusson and Bourget, 2005; Bolam et al., 2011). Finally, both of these equations can be easily calculated using data directly available from existing Chesapeake Bay Program data sets.
Rights
Included with kind permission from the author(s).
Repository Citation
Dauer, Daniel M.; Lane, Michael F.; Llansó, Roberto J.; and Diaz, Robert, "Preliminary Evaluations of Secondary Productivity Estimates as Indicators of the Ecological Value of the Benthos to Higher Trophic Levels in Chesapeake Bay" (2011). Benthic Applications. 1.
https://digitalcommons.odu.edu/chesapeakebay-archive_benthic/1
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