The use of the Pinkham-Pearson index for the comparison of community structure in Biosim2 to identify statistically-valid sectors of taxa By Carlos Pinkham Biology Department & Darlene Olsen Mathematics Department Norwich University Northfield, VT & J. Gareth Pearson Brian Reid EPA, Retired Dartmouth Medical School Las Vegas, NV Dartmouth, NH

Using the Pinkham-Pearson index in Biosim2 to identify statistically-valid sectors of community structure and other aspects of the Streams Project Study Outline Origin of Pinkham-Pearson Index of Biotic Similarity Introduction –Pinkham-Pearson Index –Biosim2 –Sectors VTDEC Ambient Biomonitoring Program Results –Macroinvertebrate % Composition Data –Statistically Valid Sectors Conclusions

Community Structure (Species Composition) Species occurrence and abundance (that is, both the kinds and numbers of species present) Measures of Community Structure Being Used in Pollution Surveys in 1970s Gleason's Richness Index Shannon's Diversity Index Simpson's Index of Dominance Brillouin's Index Menhinik's Richness Index Pielou's Evenness Index McIntosh's Index

Where These Fall Short

Pinkham-Pearson Index of Biotic Similarity Barbour et al. (1992) in a systematic comparison of the metrics proposed in EPA's rapid bioassessment protocol (Pfalkin et al., 1989), concluded that B "may be the most appropriate metric to serve as a measure of community similarity."

Index of Biotic Similarity (Pinkham-Pearson Index) Original data matrix

Matrix of B’s Between 11 Habitat Parameters

Figure 1. Opening Screen of BioSim2.

What is a Sector? original data matrix, rows coded sites/taxaABCDEFG CPR CPR CPR CCR CCR CCR

Figure 1. Opening Screen of BioSim2.

Row Dendrogram What is a Sector?

original data matrix Original data matrix rearranged in order of the row dendrogram sites/taxaABCDEFG CPR CPR CPR CCR CCR CCR sites/taxaABCDEFG CCR CCR CCR CPR CPR CPR

What is a Sector? sites/taxaABCDEFG CCR CCR CCR CPR CPR CPR Original data matrix rearranged in order of the row dendrogram, taxa coded

Figure 1. Opening Screen of BioSim2.

Taxa Dendrogram What is a Sector?

Rearranging original data matrix in double-dendrogram order sites/taxaABCDEFG CCR CCR CCR CPR CPR CPR FCGDEBA CCR CCR CCR CPR CPR CPR Original data matrix rearranged in order of the row dendrogram, taxa coded What is a Sector?

Taxa Dendrogram Identifying environmentally reasonable sectors What is a Sector?

Establishing environmentally reasonable sectors What is a Sector?

VTDEC Ambient Biomonitoring Program The Vermont Department of Environmental Conservation (VTDEC) is charged with assessing the biological integrity of wadable stream sites throughout Vermont. Specific data are being collected to better refine the biological expectation of very small (<1-15 km 2 ), low elevation ( ft), eurythermal, wadable streams of moderate gradient in Vermont. These data will be used to evaluate the response of these streams to current agricultural and storm-water management practices, within their watersheds.

Small, Moderate Gradient (Wadable) Streams From this Program 27 streams were selected, 26 in the Champlain Valley, One in the Connecticut Valley One stream was sampled in 2 successive years to provide a reference for the technique. One stream was sampled at two points Thus data from “29” streams were used in this study.

Macroinvertebrate Results 170 taxa collected at 29 “Sites” Compressed to 91 taxa at 29 Sites by eliminating – taxa which appeared in only one site with a % composition < 1.25% (38) – taxa which appeared in only two sites with a maximum % comp < 1.2% (23) –taxa which appeared in only three sites with a maximum % comp < 1.1% (11) –taxa which appeared in only four sites with a maximum % comp < 1% (7)

Zero’s Present Zero’s Removed

Statistical Analysis Assumptions –The measurements in each site are independent –The relative abundances of taxa follow a normal distribution Independent

Statistical Analysis Calculations i = 1, …, k

Statistical Analysis Calculations H o : There is a not a significant difference between the relative abundance of taxa in Sector 1 and Sector 2 sites. H a : There is a significant difference between the relative abundance of taxa in Sector 1 and Sector 2 sites. Given H o is true then The p-value is calculated using the chi-square distribution.

S S D D S S D D D S D D D D D S D D S: There is a not a significant difference in the % compositions of this group of taxa between the two groups of sites (between the two sectors). D: There is a significant difference in the % compositions of this group of taxa between the two groups of sites (between the two sectors).

A quick example will show you how BioSim2 works

Acknowledgements The authors wish to thank: The EPSCoR Baccalaureate College Summer Research Program under NSF Grant Number, EPS for funding The Norwich University Faculty Development Program for funding The Vermont DEC for permission to use their data in this presentation

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