Northeastern Naturalist Vol. 22, Monograph 12 T.G. Gerwing, A.M. Allen Gerwing, D. Drolet, M.A. Barbeau, and D.J. Hamilton 2015 1 2015 NORTHEASTERN NATURALIST Spatiotemporal Variation in Biotic and Abiotic Features of Eight Intertidal Mudflats in the Upper Bay of Fundy, Canada Travis G. Gerwing1,*, Alyssa M. Allen Gerwing1, David Drolet2, Myriam A. Barbeau1, and Diana J. Hamilton2 Abstract - We examined biotic and abiotic variables on the expansive intertidal mudflats of the upper Bay of Fundy, Canada, at 8 geographically separate sites over 2 years (2009–2011). Invertebrate density, surface density of primary producers (mainly diatoms, measured as chlorophyll-a concentration), shorebird- and fish-foraging activity, and sediment properties varied considerably through time and space. Dissimilarity in the invertebrate community between consecutive sampling rounds was lower during peaks in density and richness (June–August) than during periods of low density and richness (December– March). All but one site located within Chignecto Bay (one arm of the upper Bay of Fundy) had similar invertebrate communities; sites within the Minas Basin (the other arm of the upper Bay) had more distinct communities compared to Chignecto Bay mudflats. The amphipod Corophium volutator, Copepoda, Ostracoda, and the polychaetes Phyllodocidae and Spionidae were usually main contributors to observed community differences over space and time. Although our sites are all silt-dominated mudflats, mean particle size, sediment penetrability, and depth to the apparent redox discontinuity potential (aRDP, a measure of sediment-oxygen content) were usually main contributors to site differences in sediment conditions. However, when we pooled samples over sites and sampling rounds, percent water content and percent organic-matter content accounted for the majority of the variation in sediment properties, likely reflecting within-site patchiness. Such quantification of spatiotemporal patterns in biotic and abiotic variables is an essential first step in the development of predictive models or the design of manipulative experiments to investigate ecological relationships. Introduction Intertidal mudflats in the Bay of Fundy support a highly abundant and relatively diverse assemblage of infaunal species (Drolet et al. 2009, Featherstone and Risk 1977, Wilson 1988). Infaunal densities greater than 200,000 individuals m-2 are possible due to highly productive populations of benthic diatoms that form the base of this food web (Hargrave et al. 1983, Trites et al. 2005). Diatom production is supplemented by high inputs of detritus, likely from local saltmarshes (Gordon et al. 1986, 1987; Stuart et al. 1985), further enhancing the productivity of this system (Hargrave et al. 1983). Additionally, this system maintains a diverse group of epibenthic predators such as benthic fish (McCurdy et al. 2005, Risk and Craig 1976), 1Department of Biology, University of New Brunswick, Fredericton, NB, Canada, E3B 5A3. 2Department of Biology, Mount Allison University, Sackville, NB, Canada, E4L 1G7. *Corresponding author - t.g.gerwing@gmail.com. Manuscript Editor: Trevor Avery 22(Monograph 12):1–44 Northeastern Naturalist 2 T.G. Gerwing, A.M. Allen Gerwing, D. Drolet, M.A. Barbeau, and D.J. Hamilton 2015 Vol. 22, Monograph 12 Nassarius obsoletus (Say) (Eastern Mudsnail; Coffin et al. 2012), and shorebirds (Hicklin 1987, Hicklin and Smith 1984). The intermediate level of organismal diversity of the intertidal-mudflat community is ideal for quantifying and understanding ecological interactions; however, spatiotemporal dynamics of this system in the upper Bay of Fundy are understudied. Most relevant Bay of Fundy studies have focused on a few key residents or visitors, such as the amphipod Corophium volutator (Pallas) (e.g., Drolet and Barbeau 2012), Eastern Mudsnail (Coffin et al. 2012), and Calidris pusilla (L.) (Semipalmated Sandpiper; e.g., Hamilton et al. 2006). Moreover, the spatiotemporal variation of mudflat-sediment properties in this region (particle size, percent water, and organic content, etc.) is mostly unreported. Therefore, the goal of our study was to quantify how biotic and abiotic variables varied through space and time, and determine which of these variables contributed most to community and environmental patterns. This study provides the foundation for a companion paper that quantifies the relative importance of biotic and abiotic variables to infaunal population densities and community dynamics on intertidal mudflats (T.G. Gerwing et al., unpubl. data). Methods Study sites We conducted our study on intertidal-mudflat sites in the 2 arms (Chignecto Bay, Minas Basin) of the upper Bay of Fundy, Canada (Fig. 1; see supplemental Table S1 in Supplemental File 1, available online at https://www.eaglehill.us/NENAonline/ Figure 1. Study sites (i.e., intertidal mudflats) in the Bay of Fundy, Canada. Site names are Starrs Point (SP), Avonport (AV), Moose Cove (MC), Minudie (MN), Pecks Cove (PC), Grande Anse (GA), Daniels Flats (DF), and Mary’s Point (MP). Northeastern Naturalist Vol. 22, Monograph 12 T.G. Gerwing, A.M. Allen Gerwing, D. Drolet, M.A. Barbeau, and D.J. Hamilton 2015 3 suppl-files/n22-4-N1354-Gerwing-s1). We sampled 8 mudflats: 5 in Chignecto Bay (Mary’s Point [MP], Daniels Flats [DF], Grande Anse [GA], Pecks Cove [PC], and Minudie [MN]), and 3 in the Minas Basin (Moose Cove [MC], Avonport [AV], and Starrs Point [SP]). We selected these sites because they represent large, siltdominated intertidal mudflats, reported to be visited by Semipalmated Sandpipers in the past, and they cover the extent of the upper Bay of Fundy (Gerwing et al. 2013, Hicklin et al. 1980, Yeo 1977). Mudflat sampling Fauna. We sampled mudflats over 2 years (2009–2011) every 3 weeks between June and August, and every 6–8 weeks between October and May (Gerwing et al. 2013). We sampled 2 randomly chosen mudflats per day, during the period 3 h before to 3 h after low tide; all mudflats were sampled within a 5-d period for a given sampling round (the date indicated in our figures represents the first day of a sampling round). Sampling rounds occurred at approximately the same time each year (±1 week). We established 2 transects at each mudflat, running perpendicular to the low-water line and located 700–1000 m from each other, depending on the along-shore length of the mudflat. Transects were 700–1800 m long (depending on the across-shore length of the mudflat) from the shoreward start of the mudflat to the highest low-tide line. We divided the transects into 4 equal zones based on distance from shore, for random stratified sampling. For mudflat infauna, we randomly selected 3 sampling plots of 1 m2 per zone, for a total of 12 plots per transect (n = 22–24 per site, 3070 total). At each plot, we pushed a 7-cm-diameter corer into the sediment as deep as possible—about 5–10 cm until hard bottom or the end of the corer was reached. Within 12 h of collection, we passed the samples through a 250-μm sieve to retain all life stages of benthic macrofauna (see Crewe et al. 2001 with regard to Corophium volutator), as well as large meiofauna, and preserved them in 95% ethanol. We later sorted the preserved samples, and identified and counted invertebrates under a dissecting microscope. We quantified densities of C. volutator, Macoma spp.—M. balthica (L.) (Hicklin et al. 1980) and/or M. petalum (Valenciennes) (Nikula et al. 2007)—Copepoda (identified to subclass, mostly from the order Harpacticoida), Ostracoda (identified to class), and Polychaeta (identified to family). We counted Eastern Mudsnails in the 1-m2 plots in situ. Other biotic variables. For each plot, we determined the concentration of chlorophyll a, an indicator of diatom abundance, in the top 2–3 mm of sediment as described in Coulthard and Hamilton (2011). We also quantified the proportion of the 1-m2 plot covered in shorebird footprints, predominantly Semipalmated Sandpipers, in July–August. This variable is an indication of sandpiper-habitat use (MacDonald et al. 2012, Robar and Hamilton 2007), and a good measure of foraging activity within the plot because sandpipers spend the majority of their time foraging while on the mudflats (MacDonald et al. 2012). We also counted fishfeeding traces (termed fish bites) within each plot. See Risk and Craig (1976) and McCurdy et al. (2005) for images of fish bites and identification criteria. Northeastern Naturalist 4 T.G. Gerwing, A.M. Allen Gerwing, D. Drolet, M.A. Barbeau, and D.J. Hamilton 2015 Vol. 22, Monograph 12 Sediment properties. In each plot, we assessed sediment penetrability by dropping a metal rod (15 cm long, 1.9 cm diameter, 330 g) from a 0.75 m above the substratum (i.e., distance from the top of the rod to the top of the mudflat surface) and recording the depth that the rod (mm) penetrated into the sediment (Kennedy 2012). We developed this meathod as an index of how easily water and biota would be able to penetrate into the sediment. We measured depth of the apparent redox potential discontinuity (aRPD), an index of sediment dissolved oxygen content (Gerwing et al. 2015a), to the nearest 0.5 cm in the void left in the sediment following removal of the 7-cm-diameter core (for infaunal sampling) in each plot, as described in Gerwing et al. (2013). To determine additional sediment properties, we collected 1 sediment sample from each zone using a 5-cm-long x 3-cm-diameter corer (n = 6–8 per site, 1021 total). We separated and weighed the top 1 cm of each core, placed the samples in a drying oven at 110 °C for 12 h, and weighed them again before temporary storage in a desiccator. We calculated percent water-content as: (mass wet sediment – mass dry sediment) / (mass wet sediment) x 100 We ashed dry sediment samples in a muffle furnace at 550 °C for 4 h and weighed the products; percent organic content was calculated as: (mass dry sediment – mass of ashed sediment) / (mass of dry sed iment) x 100 We then determined volume-weighted mean particle-size of the sediment for each sample using a Malvern Mastersizer 2000 (www.malvern.com); particle size was measured in triplicate and a mean value per sample was calculated (Rodriguez 2005, Savoie 2009). Data analysis We used the statistical program PRIMER with the PERMANOVA (Permutational Multivariate Analysis of Variance) add-on (McArdle and Anderson 2001) to examine how the mudflat-invertebrate community and sediment conditions varied over space and time. In our analyses, we set α = 0.05 to indicate significance. The invertebrate community was comprised of 1 epifaunal species (Eastern Mudsnail), and the following infaunal taxa: Macoma spp., C. volutator, Copepoda, Ostracoda, and Polychaetes (Capitellidae, Spionidae, Cirratulidae, Maldanidae, Nereididae, Nephtyidae, Phyllodocidae, Glyceridae, Goniadidae, and Orbiniidae; densities of Goniadidae and Orbiniidae are not presented graphically because these polychaetes were very rare). For this community, we calculated a resemblance matrix using Bray-Curtis coefficients (Clarke et al. 2006). We added a dummy variable of 1, which was considered a “dummy species” in the analysis, so that we could include plots with density values of zero (Clarke and Gorley 2006). Data were fourth-root transformed (x1/4) to improve assessment of effects of rare and common taxa on community structure. In the PERMANOVA, site (8 levels), round (8 levels), and year (2 levels) were fixed factors; transect (2 levels) nested within site, and plot (the error term) were random factors. Due to a significant 3-way interaction between fixed factors (site x round x year), we conducted a separate PERMANOVA Northeastern Naturalist Vol. 22, Monograph 12 T.G. Gerwing, A.M. Allen Gerwing, D. Drolet, M.A. Barbeau, and D.J. Hamilton 2015 5 for each year. There was a significant site x round interaction in both years; thus, we conducted a PERMANOVA for each site separately as a posthoc analysis to assess site-specific temporal dynamics. We employed a sequential Bonferroni-type P-value correction (Benjamini and Hochberg 1995). We analyzed chlorophyll-a concentrations with a PERMANOVA with no data transformation, a resemblance matrix calculated using Euclidean distances, and factors as above. We handled significant 3-way (site x round x year) and 2-way (site x round) interactions in the same way as the invertebrate PERMANOVA. We did not conduct PERMANOVAs on sandpiper footprints or fish bites because these indicators were highly scattered in time and space. For the PERMANOVA on sediment properties, we normalized variables (mean particle size, percent water content, percent organic-matter content, aRPD depth, and sediment penetrability) before analysis, and calculated the resemblance matrix using Euclidean distances. As above, site (8 levels), round (8 levels), and year (2 levels) were fixed factors. We did not include transect as a random factor because sediment cores (one per zone) were collected far apart (82–806 m) from one another and preliminary analysis indicated abiotic conditions did not vary by transect (P > 0.1). We evaluated significant 3-way (site x round x year) and 2-way (site x round) interactions in the same way as for the invertebrate PER MANOVA. We employed non-metric multidimensional scaling (MDS, 100 restarts) graphs to visualize both invertebrate-community composition and sediment conditions at our study sites over 2 years. Points closer together on the MDS graphs represent sampling plots with a biotic community or set of abiotic conditions more similar than points for sampling plots further apart. Overlaid vectors represent the correlations (Pearson correlation coefficients) between taxa or sediment variables and MDS axes. All MDS graphs had a stress less than 0.2, and so we considered them a good 2-dimensonal representation of higher dimensional trends (Clark e 1993). We used SIMPER (similarity percentages; Clarke 1993, Clarke and Ainsworth 1993) to identify the contribution of each variable (biotic or abiotic) to significant spatiotemporal differences. Also, we calculated the ratio of each variable’s average dissimilarity to the standard deviation of dissimilarities (Diss/SD) for biota, or average squared Euclidean distance to the standard deviation of squared distances (Sq.Dist/SD) for sediment properties. These values represent how consistently each variable contributed to observed differences; variables with a ratio greater than 1 consistently contributed to the difference, whereas those with a value below 1 did not. Herein, we report SIMPER results for difference both between sites and between sampling round for invertebrate-community change. For the sediment SIMPER analysis we present only inter-site results; we do not provide inter-round results because the magnitude of the difference was relatively small and, in some cases, not significant. Finally, we performed a distance-based redundancy analysis (dbRDA) on the sediment properties. This method uses principal-component ordination to create a series of axes, in this case composed of our sediment variables, to represent our sediment environment independent of site and time (Clarke and Gorley 2006, McArdle and Anderson 2001). Northeastern Naturalist 6 T.G. Gerwing, A.M. Allen Gerwing, D. Drolet, M.A. Barbeau, and D.J. Hamilton 2015 Vol. 22, Monograph 12 Results and Discussion Invertebrate community The invertebrate community on intertidal mudflats in the upper Bay of Fundy varied significantly through space and time (Table 1). Although substantial variation existed, richness and invertebrate density (total and taxon-specific) tended to peak in July–August, decrease from October through March or May (depending on the taxon), and then rise again (Figs. 2–13; see supplemental Figs. S1–S5 in Supplemental File 1, available online at https://www.eaglehill.us/NENAonline/ suppl-files/n22-4-N1354-Gerwing-s1). To the best of our knowledge, this is the first Table 1. PERMANOVA results investigating whether the invertebrate community (resemblance matrix calculated from 4th-root–transformed density data) varied through space and time on intertidal mudflats in the Bay of Fundy during 2009–2011. * = significant and interpretable P-values of fixed effects. Due to a significant 3-way interaction (site x round x year, pseudo-F = 2.1, P = 0.001); the analysis was conducted by year. Multiple comparisons to determine if each site varied over time (site x round interaction) were interpreted with P values corrected using a sequential Bonferroni-type adjustment. See Figure 1 for site names associated with site code s. Source of variation df MS Pseudo-F Unique permutations P 2009–2010 Site 7 102,870 21.7 997 0.001 Season 7 20,625 22.9 997 0.001 Site x Season 49 3533 3.9 998 0.001* SP 7 20,625 22.9 997 0.001* AV 7 8120 4.4 997 0.003* MC 7 9520 9.1 999 0.004* MN 7 3247 5.0 999 0.005* PC 7 3222 4.1 999 0.006* GA 7 7100 8.7 999 0.008* DF 7 3289 7.9 998 0.009* MP 7 4590 7.4 998 0.01* Transect (Site) 8 4739 6.4 999 0.001 Season x transect (Site) 56 900 1.2 997 0.017 Residual 1406 743 2010–2011 Site 7 122,540 32.4 999 0.001 Season 7 16,100 17.0 998 0.001 Site x Season 49 2359 2.5 996 0.001* SP 7 1690 3.8 998 0.0001* AV 7 3299 2.7 997 0.0003* MC 7 5953 4.6 999 0.0004* MN 7 7132 4.2 998 0.0005* PC 7 5333 13.7 999 0.0006* GA 7 2570 4.7 999 0.0008* DF 7 3613 4.8 999 0.002* MP 7 3024 2.4 997 0.018* Transect (Site) 8 3782 5.7 999 0.001 Season x transect (Site) 56 949 1.4 997 0.001 Residual 1408 1000 Northeastern Naturalist Vol. 22, Monograph 12 T.G. Gerwing, A.M. Allen Gerwing, D. Drolet, M.A. Barbeau, and D.J. Hamilton 2015 7 Figure 2. Mean (± SE; n = 22–24 plots per site) taxa richness in the invertebrate community on mudflats in the upper Bay of Fundy in 2009–2011. See Figure 1 for site names that correspond to codes given i n figure. Northeastern Naturalist 8 T.G. Gerwing, A.M. Allen Gerwing, D. Drolet, M.A. Barbeau, and D.J. Hamilton 2015 Vol. 22, Monograph 12 Figure 3. Mean (± SE; n = 22–24 plots per site) Nassarius obsoletus (= Ilyanassa obsoleta) (Eastern Mudsnail) density on mudflats in the upper Bay of Fundy in 2009–2011 (see Fig. 1 for site names that correspond to codes given in figure). This species is an obligate omnivore, capable of predation and deposit feeding (Coffin et al. 2012, Cu rtis and Hurd 1979, Drolet et al. 2009). Northeastern Naturalist Vol. 22, Monograph 12 T.G. Gerwing, A.M. Allen Gerwing, D. Drolet, M.A. Barbeau, and D.J. Hamilton 2015 9 Figure 4. Mean (± SE; n = 22–24 cores per site) density of Macoma spp. (M. balthica and/or M. petalum) on mudflats in the upper Bay of Fundy in 2009–2011 (see Fig. 1 for site names that correspond to codes given in figure). These clam species are mostly sessile, facultative deposit- and suspension-feeders (Rossi et al. 2004, Word 1979). Northeastern Naturalist 10 T.G. Gerwing, A.M. Allen Gerwing, D. Drolet, M.A. Barbeau, and D.J. Hamilton 2015 Vol. 22, Monograph 12 Figure 5. Mean (± SE; n = 22–24 per site) Copepoda density on mudflats in the upper Bay of Fundy in 2009–2011 (see Fig. 1 for site names that correspond to codes given in figure). Copepods (mostly from the order Harpacticoida) are likely acting as deposit feeders (Buffan- Dubau and Carman 2000). Northeastern Naturalist Vol. 22, Monograph 12 T.G. Gerwing, A.M. Allen Gerwing, D. Drolet, M.A. Barbeau, and D.J. Hamilton 2015 11 Figure 6. Mean (± SE; n = 22–24 per site) Ostracoda density on mudflats in the upper Bay of Fundy in 2009–2011 (see Fig. 1 for site names that correspond to codes given in figure). Ostracods are likely acting as filter feeders and deposit feeders (Buffan-Dubau and Carman 2000). Northeastern Naturalist 12 T.G. Gerwing, A.M. Allen Gerwing, D. Drolet, M.A. Barbeau, and D.J. Hamilton 2015 Vol. 22, Monograph 12 Figure 7. Mean (± SE; n = 22–24 per site) density of the amphipod Corophium volutator on mudflats in the upper Bay of Fundy in 2009– 2011 (see Fig. 1 for site names that correspond to codes given in figure). C. volutator is a mobile, facultative suspension- and deposit-feeder (Møller and Riisgård 2006). Northeastern Naturalist Vol. 22, Monograph 12 T.G. Gerwing, A.M. Allen Gerwing, D. Drolet, M.A. Barbeau, and D.J. Hamilton 2015 13 Figure 8. Mean (± SE; n = 22–24 per site) Capitellidae density on mudflats in the upper Bay of Fundy in 2009–2011 (see Fig. 1 for site names that correspond to codes given in figure). Capitellids are mostly sessile polychaetes that act as a subsurface deposit-feeder (Fauchald and Jumars 1979, Jumars et al. 2014, Pagliosa 2005). Northeastern Naturalist 14 T.G. Gerwing, A.M. Allen Gerwing, D. Drolet, M.A. Barbeau, and D.J. Hamilton 2015 Vol. 22, Monograph 12 Figure 9. Mean (± SE; n = 22–24 per site) Cirratulidae density on mudflats in the upper Bay of Fundy in 2009–2011 (see Fig. 1 for site names that correspond to codes given in figure). Cirratulids are mostly sessile polychaetes capable of both suspension and deposit feeding (Fauchald and Jumars 1979, Pagliosa 2005). Deposit feeding may be at the sediment surface or subsurface (Jumars et al. 2014). Northeastern Naturalist Vol. 22, Monograph 12 T.G. Gerwing, A.M. Allen Gerwing, D. Drolet, M.A. Barbeau, and D.J. Hamilton 2015 15 Figure 10. Mean (± SE; n = 22–24 per site) Spionidae density on mudflats in the upper Bay of Fundy in 2009–2011 (see Fig. 1 for site names that correspond to codes given in figure). Spionids are mostly sessile polychaetes capable of both suspension and deposit feeding (Fauchald and Jumars 1979, Jumars et al. 2014, Pagliosa 2005). Northeastern Naturalist 16 T.G. Gerwing, A.M. Allen Gerwing, D. Drolet, M.A. Barbeau, and D.J. Hamilton 2015 Vol. 22, Monograph 12 Figure 11. Mean (± SE; n = 22–24 per site) Phyllodocidae density on mudflats in the upper Bay of Fundy in 2009–2011 (see Fig. 1 for site names that correspond to codes given in figure). Phyllodocidae are mobile omnivorous polychaetes, capable of deposit feeding on detritus and diatoms, as well as predation (Fauchald and Jumars 1979, Ju mars et al. 2014, Pagliosa 2005). Northeastern Naturalist Vol. 22, Monograph 12 T.G. Gerwing, A.M. Allen Gerwing, D. Drolet, M.A. Barbeau, and D.J. Hamilton 2015 17 Figure 12. Mean (± SE; n = 22–24 per site) Nereididae density on mudflats in the upper Bay of Fundy in 2009–2011 (see Fig. 1 for site names that correspond to codes given in figure). Nereids are mobile polychaetes with varied foraging strategies. They are omnivores that can act as detritivores or predators, as well as suspension and deposit feeders (Fauchald and Jumars 1979, Jumars et al. 2014, Pagliosa 2005, Scaps 2002). Northeastern Naturalist 18 T.G. Gerwing, A.M. Allen Gerwing, D. Drolet, M.A. Barbeau, and D.J. Hamilton 2015 Vol. 22, Monograph 12 Figure 13. Mean (± SE; n = 22–24 per site) Nephtyidae density on mudflats in the upper Bay of Fundy in 2009–2011 (see Fig. 1 for site names that correspond to codes given in figure). Nephtyidae are mobile polychaetes that are omnivorous predators, and are also capable of deposit feeding (Caron et al. 2004, Fauchald and Jumars 1979, J umars et al. 2014, Pagliosa 2005). Northeastern Naturalist Vol. 22, Monograph 12 T.G. Gerwing, A.M. Allen Gerwing, D. Drolet, M.A. Barbeau, and D.J. Hamilton 2015 19 study that quantifies the densities of these animals, especially the polychaetes, over such a broad spatiotemporal scale in this region. Early spatiotemporal studies of intertidal mudflats in the upper Bay of Fundy such as those by Yeo (1977), Gratto (1979), Hicklin et al. (1980), and Wilson (1988) are useful, but each focused on either the Minas Basin or Chignecto Bay and had a smaller temporal extent. In our study, despite the observed spatiotemporal variation (Figs. 2–13; see supplemental Figs. S1–S5 in Supplemental File 1, available online at https://www.eaglehill.us/ NENAonline/suppl-files/n22-4-N1354-Gerwing-s1), most sites within Chignecto Bay (MN, PC, DF, MP) tended to cluster together on the MDS graph (Fig. 14). GA, SP, AV, and MC tended to group separately from other sites, as well as each other (Fig. 14). This spatiotemporal variation in community composition, richness, and population density could be a result of interspecific interactions (Cheverie et al. 2014, Fraser et al. 2006, Hamilton et al. 2006, Heck and Valentine 2007), intraspecific interactions (Drolet et al. 2013a, Jensen and Kristensen 1990, Skilleter and Peterson 1994, Wilson 1989), as well as interactions between the biota and the physical environment (Coelho et al. 2013, Levinton and Kelaher 2004, Meadows 1964, Silva et al. 2006, Sturdivant et al. 2012). A recent analysis focusing on factors associated with this infaunal variation indicated that although predation, resource availability, and certain abiotic sediment factors were significantly related to community patterns, they accounted for only a small part of infaunal-community variation across space and time (T.G. Gerwing et al., unpubl. data). Structural factors such as site and plot accounted for the majority of the community variation, which suggested that processes such as hydrodynamics, larval supply, and postsettlement dispersal may be important (T.G. Gerwing et al., unpubl. data). Percent dissimilarity, calculated as community change between successive sampling rounds, was relatively high all year (25–65%; Fig. 15). However, a temporal pattern in percent dissimilarity was present, with less variability over time during periods when densities and richness were high or increasing (June–August). In contrast, when density and richness were low or decreasing (December–March), the community varied more over time. This pattern reflects the fact that during annual density peaks, most taxa were present at all sites and in relatively high densities; accordingly, percent dissimilarity over time was relatively low (25–45%; Fig. 15). However, as winter approached and progressed, density and richness decreased, likely a result of decreasing photoperiod (Lindqvist et al. 2013, Williams et al. 2013), effect of winter stressors (Gerwing et al. 2015b), and depletion of internal energy reserves (Drolet et al. 2013b). This decrease in invertebrate density resulted in increased variation in community composition over time, and a correspondingly higher percent dissimilarity (45–65%; Fig. 15). Our results regarding temporal patterns showed that the contribution of each taxon to community differences between sequential sampling rounds varied among years, time of year, and site (Appendix 1, Fig. 14). The contribution was partly dependent on actual abundances. For instance, Cirratulidae contributed substantially to between-round differences at SP and AV (9–20%), where densities were high (Fig. 9, Appendix 1). At sites where its density was low, Cirratulidae Northeastern Naturalist 20 T.G. Gerwing, A.M. Allen Gerwing, D. Drolet, M.A. Barbeau, and D.J. Hamilton 2015 Vol. 22, Monograph 12 Figure 14. Non-metric multidimensional scaling (nMDS) graphs of the invertebrate-community composition (4th-root transformed density data) of 8 intertidal mudflats in the upper Bay of Fundy and 8 sampling rounds per year over 2 years (2009– 2011). Each symbol represents an average per site and round. 1 = early June, 2 = late June, 3 = mid- July, 4 = early August, 5 = late August/early September, 6 = October, 7 = December, and 8 = March (for more precise dates, see Fig. 2). See Figure 1 for site names that correspond to codes given in figure. Vector overlays beneath the MDS graphs represent correlations between taxa and MDS axes. The vector of each taxon shows the direction of increased density across the MDS graph. Only correlations > 0.3 are shown. Northeastern Naturalist Vol. 22, Monograph 12 T.G. Gerwing, A.M. Allen Gerwing, D. Drolet, M.A. Barbeau, and D.J. Hamilton 2015 21 Figure 15. Percent dissimilarity (SIMPER results) between consecutive pairs of sampling rounds for the invertebrate community (4th-root transformed density data) at 8 intertidal mudflats in the upper Bay of Fundy in 2009–2011 (See Fig. 1 for site names that correspond to codes given in figure). Each symbol represents an average per site and round. 1 = early June, 2 = late June, 3 = mid-July, 4 = early August, 5 = late August/early September, 6 = October, 7 = December, and 8 = March (for more precise dates, see Fig. 2). See Figure 1 for site names that correspond to codes given in figure. Northeastern Naturalist 22 T.G. Gerwing, A.M. Allen Gerwing, D. Drolet, M.A. Barbeau, and D.J. Hamilton 2015 Vol. 22, Monograph 12 contributed little to community differences (less than 2% at MN and PC). Despite the variation, C. volutator, Copepoda, Ostracoda, and Spionidae were usually among the largest and most-consistent contributors to inter-round community differences (Appendix 1), suggesting that these taxa experienced greater seasonal variation than others. We speculate that these taxa may respond more strongly to seasonal cues than other taxa, therefore, varying more over a year. The contribution by Nephtyidae, Nereididae, Phyllodocidae, Capitellidae, Cirratulidae, and Macoma spp. was less consistent. These taxa accounted for a moderate to high percent of the temporal community differences at some sites (especially where they had relatively high densities), but were minor contributors at other sites. The polychaetes Maldanidae, Glyceridae, Orbiniidae, and Goniadidae never accounted for a substantial amount of the community differences. The Eastern Mudsnail was a fairly consistent contributor of small to moderate amounts of the temporal community differences, especially during mid-summer to mid-fall. In terms of spatial patterns, the contribution of each taxon to community differences between pairs of sites was also variable (Appendix 2, Fig. 14). Despite the variation, C. volutator, Copepoda, Ostracoda, Spionidae, and Phyllodocidae were usually main and consistent contributors. Gerwing et al. (2015b) observed that these species also accounted for the majority of over-winter community change on the mudflats. Goniadidae, Glyceridae, Maldanidae, and Orbiniidae were negligible contributors. The contributions from the remaining taxa were less consistent, with higher values corresponding to sites with higher abundances of that taxon. A previous analysis of infaunal-community structure at different mudflat sites, but focussing on microhabitats (i.e., inside and outside tide pools at 3 [DF, GA, and PC] sites in Chignecto Bay) at 1 sampling time (June), revealed that C. volutator was again a primary contributor (Drolet and Barbeau 2009). Other biotic variables Chlorophyll-a concentration, an indicator of primary-producer standing crop at the mudflat surface, varied through space and time (Table 2). In general, concentrations tended to peak in July–August and reach a low level October–December (Fig. 16). These annual cycles are likely strongly influenced by nutrient availability, temperature, and photoperiod (Admiraal et al. 1982, Hargrave et al. 1983, Scholz and Liebezeit 2012, Trimbee and Harris 1984). Fish bites, evidence of fish-feeding activity on the benthic infauna (McCurdy et al. 2005, Risk and Craig 1976), varied considerably between sites, years and seasons; however, mean density of fish bites was low (see Supplemental File 1, see supplemental Fig. S4 in Supplemental File 1, available online at http://www. eaglehill.us/NENAonline/suppl-files/n22-4-N1354-Gerwing-s1). In general, we observed more fish bites during June–August than October–March, and more in 2009–2010 than in 2010–2011. Finally, we observed sandpiper footprints in our August sampling (see supplemental Fig. S5 in Supplemental File 1, available online at https://www.eaglehill.us/NENAonline/suppl-files/n22-4-N1354-Gerwing-s1). Semipalmated Sandpipers visit the upper Bay of Fundy for a short, intense time Northeastern Naturalist Vol. 22, Monograph 12 T.G. Gerwing, A.M. Allen Gerwing, D. Drolet, M.A. Barbeau, and D.J. Hamilton 2015 23 during August (Bart et al. 2007, Hicklin and Smith 1984), but within that period we observed variation among sites and years. Sediment properties Sediment properties of the Bay of Fundy mudflats varied through space and time (Table 3, Figures 17–20; aRPD-depth patterns are available in Gerwing et al. 2013). Although the sediment environment varied significantly over time at most sites, it remained consistent at DF in both years and at MP in 2010–2011 (Table 3). Overall, several temporal patterns of variation were apparent. Volume-weighted mean particle-size fluctuated between peaks and troughs annually; however, the timing Table 2. PERMANOVA results investigating whether chlorophyll-a concentration in the top 2–3 mm of sediment varied through space and time on intertidal mudflats in the Bay of Fundy in 2009–2011. * = significant and interpretable P-values of fixed effects. Due to a significant 3-way interaction (site x round x year: pseudo-F = 9.1, P = 0.001), the analysis was conducted by year. Multiple comparisons to determine if each site varied over time (site x round interaction) were interpreted with P-values corrected using a sequential Bonferroni-type adjustment. See Figure 1 for site names that correspond to codes given in the table. Source of variation df MS Pseudo-F Unique permutations P 2009–2010 Site 7 4066 91.2 999 0.001 Round 7 4986 116.9 999 0.001 Site x round 49 1192 27.9 998 0.001* SP 7 904 10.4 998 0.0001* AV 7 9098 94.5 999 0.0003* MC 7 2494 15.2 999 0.0004* MN 7 73 11.0 993 0.0005* PC 7 77 8.6 997 0.0006* GA 7 268 14.2 998 0.0008* DF 7 96 13.2 997 0.0009* MP 7 313 31.3 998 0.001* Transect (site) 8 45 0.89 998 0.535 Round x transect (site) 56 43 0.85 999 0.79 Residual 1406 50 2010–2011 Site 7 1623 16.5 998 0.001 Round 7 1954 26.3 999 0.001 Site x round 49 265 3.6 997 0.001* SP 7 903 18.5 998 0.0001* AV 7 1641 11.5 998 0.0003* MC 7 413 13.7 997 0.0004* MN 7 124 11.4 996 0.0005* PC 7 77 7.8 995 0.0006* GA 7 312 22.0 989 0.0008* DF 7 94 4.5 997 0.0009* MP 7 248 6.5 996 0.001* Transect (site) 8 99 2.6 999 0.006 Round x transect (site) 56 74 2.0 999 0.001 Residual 1408 38 Northeastern Naturalist 24 T.G. Gerwing, A.M. Allen Gerwing, D. Drolet, M.A. Barbeau, and D.J. Hamilton 2015 Vol. 22, Monograph 12 Figure 16. Mean (± SE; n = 16–24 cores per site) chlorophyll-a concentration of the top 2–3 mm of sediment on mudflats in the upper Bay of Fundy in 2009–2011 (See Fig. 1 for site names that correspond to codes given in figure). Chlorophyll-a concentration is an indicator of the density of photosynthetic diatoms and bacteria in the sediment (Coulthard and Hamilton 2011, Hargrave et al. 1983, Trites et al. 2005). Northeastern Naturalist Vol. 22, Monograph 12 T.G. Gerwing, A.M. Allen Gerwing, D. Drolet, M.A. Barbeau, and D.J. Hamilton 2015 25 of the peak and the magnitude varied between site and year (Fig. 17). Percent water and organic-matter content of sediments tended to be higher in the spring/summer (June–August) than winter (October–March) (Figs. 18, 19); however, this pattern varied. At some sites, organic-matter content peaked during or after winter (December– March). This result might be due to seasonally low densities of deposit feeders which consume organic matter, resulting in an accumulation of organic matter over winter (Levinton and Kelaher 2004). It may also be due to temporal variation in deposition of saltmarsh detritus for mudflats situated near saltmarshes (Gordon et al. 1986, 1987). Finally, sediment penetrability tended to be greater early in the year (June–August) than later (October–December; Fig. 20). A previous analysis focusing on over-winter change between December and March, found that sediment conditions within a site were fairly consistent (Gerwing et al. 2015b). Based on the graphs in the current study (Figs. 17–20), temporal change in sediment properties Table 3. PERMANOVA results investigating whether sediment properties (water content, penetrability, aRPD depth, particle size, and organic-matter content of sediment; normalized) at the mudflats varied through space and time in the Bay of Fundy in 2009–2011. * = significant and interpretable Pvalues of fixed effects. Due to a significant 3-way interaction (site x round x year: pseudo-F = 2.3, P = 0.001); the analysis was conducted by year. Multiple comparisons to determine if each site varied over time (site x round interaction) were interpreted with P-values corrected using a sequential Bonferronitype adjustment. See Figure 1 for site names that correspond to codes given in table. Source of variation df MS Pseudo-F Unique permutations P 2009–2010 Site 7 86 27.9 999 0.001 Round 7 28 9.1 999 0.001 Site x Round 49 8 2.5 997 0.001* SP 7 13 3.1 999 0.0001* AV 7 13 3.4 997 0.0003* MC 7 14 3.8 997 0.0004* MN 7 10 2.3 998 0.003* PC 7 13 3.3 997 0.0006* GA 7 13 3.2 999 0.0008* DF 7 8 1.7 998 0.06 MP 7 14 3.6 997 0.001* Residual 446 3 2010–2011 Site 7 107 34.7 998 0.001 Round 7 16 5.2 997 0.001 Site x round 49 6 2.0 998 0.001* SP 7 8 1.6 998 0.04* AV 7 8 1.8 998 0.02* MC 7 13 3.4 998 0.0001* MN 7 13 3.1 998 0.0003* PC 7 10 2.3 997 0.0008* GA 7 9 1.9 997 0.005* DF 7 7 1.5 999 0.13 MP 7 7 1.6 997 0.07 Residual 447 3 Northeastern Naturalist 26 T.G. Gerwing, A.M. Allen Gerwing, D. Drolet, M.A. Barbeau, and D.J. Hamilton 2015 Vol. 22, Monograph 12 Figure 17. Average (± SE; n = 6–8 cores per site) volume-weighted mean particle-size in the top 1 cm of sediment on mudflats in the upper Bay of Fundy in 2009–2011 (See Fig. 1 for site names that correspond to codes given in figure). Northeastern Naturalist Vol. 22, Monograph 12 T.G. Gerwing, A.M. Allen Gerwing, D. Drolet, M.A. Barbeau, and D.J. Hamilton 2015 27 Figure 18. Mean (± SE; n = 6–8 cores per site) sediment water-content in the top 1 cm of sediment on mudflats in the upper Bay of Fundy in 2009–2011 (See Fig. 1 for site names that correspond to codes given in figure). Northeastern Naturalist 28 T.G. Gerwing, A.M. Allen Gerwing, D. Drolet, M.A. Barbeau, and D.J. Hamilton 2015 Vol. 22, Monograph 12 Figure 19. Mean (± SE; n = 6–8 cores per site) sediment organic matter content in the top 1 cm of sediment on mudflats in the upper Bay of Fundy in 2009–2011 (See Fig. 1 for site names that correspond to codes given in figure). Northeastern Naturalist Vol. 22, Monograph 12 T.G. Gerwing, A.M. Allen Gerwing, D. Drolet, M.A. Barbeau, and D.J. Hamilton 2015 29 Figure 20. Mean (± SE; n = 22–24 per site) penetrability of the sediment on mudflats in the upper Bay of Fundy in 2009–2011 (See Fig. 1 for site names that correspond to codes given in figure). Penetrability is defined as the distance an object of known weight (a small rod of 330 g), dropped from a known height (0.75 m), penetrates into t he sediment. Northeastern Naturalist 30 T.G. Gerwing, A.M. Allen Gerwing, D. Drolet, M.A. Barbeau, and D.J. Hamilton 2015 Vol. 22, Monograph 12 throughout a year were relatively smooth, i.e., there did not appear to be a time of year when there was a consistent, dramatic change. Large temporal change in sediment conditions may occur following storm events (T.G. Gerwing, pers. observ.; Yeo 1977), and/or occur on larger time scales (Desplanque and Mossman 2004, Levin 1984, Shepherd and Boates 1999, Shepherd et al. 1995). There was substantial intersite variation in sediment properties, even though the sites are all silt-dominated intertidal mudflats (Fig. 21). When we made pairwise comparisons of the sites (SIMPER; Table 4), the contribution of each variable to the intersite difference varied greatly. Mean particle size (10 of the 28 pairs), sediment penetrability (7 pairs), and aRPD depth (6 pairs) were typically the main contributors. When we examined the sediment-data cloud as a whole (dbRDA; Table 5), the axis composed predominantly of organic matter and percent water-content contributed the most to spatiotemporal variation in sediment characteristics (58%). It is not surprising that organic matter and water content grouped together because they were highly and positively correlated in our study (Pearson’s correlation coefficient Table 4. SIMPER results showing percent contribution (%) of each sediment variable (normalized) to the dissimilarity in sediment environment between each pair of sites (pooled over sampling rounds and years). See Figure 1 for the full names of the 8 mudflats in the upper Bay of Fundy. * indicates a variable with a consistent contribution to site differences (i.e., a value with an [average squared distance/standard deviation of squared distances] ≥ 1). Variable SP–AV AV–MC SP–MC SP–MN AV–MN MC–MN MN–PC Particle size 22.4 42.1 37.3 4.5 26.4 41.2 3.6 Water content 18.1 16.8 18.1 24.2 20.0 16.1 28.8 Organic matter 21.2 16.5 15.8 21.1 21.8 14.2 27.9 Penetrability 20.2 12.9 17.7 22.6 14.2 14.6 17.6 aRPD depth 18.1 11.7 11.1 27.7 17.6 13.9 22.0 Variable MN–GA PC–GA GA–DF GA–MP DF–MP PC–DF PC–MP Particle size 1.9 2.5* 3.4 3.9 8.2 6.1 5.8 Water content 17.6 23.3* 22.1* 23.7* 19.0 27.8 25.6* Organic matter 21.7 23.3* 23.6* 23.6* 20.1 17.3 15.1* Penetrability 31.2 29.5* 29.3* 24.8 21.5 17.5 17.9 aRPD depth 27.6 21.4 21.5 24.0 31.1 31.5 35.6 Variable MN–DF MN–MP SP–PC SP–GA SP–DF SP–MP AV–PC Particle size 5.3 5.8 3.5 3.3 5.5 5.4 24.4 Water content 25.8 26.6 23.4 21.5 19.4 18.7 20.2 Organic matter 29.6 28.2 18.8 16.8 23.3 21.6 23.8 Penetrability 19.0 15.6 26.3 27.4 29.9 27.9 13.3 aRPD depth 20.3 23.9 28.0 31.0 21.9 26.4 18.2 Variable AV–GA AV–DF AV–MP MC–PC MC–GA MC–DF MC–MP Particle size 18.8 25.1 24.3 39.2 30.7 39.6 38.0 Water content 19.2 17.6 17.6 19.1 14.7 17.7 17.7 Organic matter 17.0 26.2 25.1 18.2 10.8 20.1 19.1 Penetrability 23.5 15.0 13.8 10.7 24.9* 11.8 12.2 aRPD depth 21.5 16.1 19.2 12.9 18.9 10.8 13.0 Northeastern Naturalist Vol. 22, Monograph 12 T.G. Gerwing, A.M. Allen Gerwing, D. Drolet, M.A. Barbeau, and D.J. Hamilton 2015 31 = 0.82, P = 0.001). This correlation is likely a result of organic matter influencing sediment cohesiveness and thus water content (Black et al. 2002, Dade et al. 1992). In our dbRDA, the variable ranked 2nd highest (17%) was depth to the aRPD, which is a useful measure of dissolved-oxygen content at a particular sampling location (Gerwing et al. 2015a). Factors which influence aRPD depth can be found Figure 21. Non-metric multidimensional scaling (nMDS) graphs of the sediment environment (aRPD depth, mean particle size, water content, organic-matter content, sediment penetrability; normalized) on 8 intertidal mudflats in the upper Bay of Fundy and 8 sampling rounds per year over 2 years (2009–2011). Each symbol represents an average per site and round. 1 = early June, 2 = late June, 3 = mid-July, 4 = early August, 5 = late August/early September, 6 = October, 7 = December, and 8 = March (for more precise dates, see Fig. 2). See Fig. 1 for site names that correspond to codes given in figure. Vector overlays beneath the MDS graphs represent correlations between sediment variables and MDS axes. The vector of each sediment variable shows the direction of increased value across the MDS graph. All sediment variables are shown. Table 5. Results of the distance-based redundancy analysis (dbRDA) on the variation in sediment properties (normalized) among samples (n = 1021) for intertidal mudflats in the upper Bay of Fundy in 2009–2011. Variation explained (%) Axis title Individual Cumulative Water- and organic-matter contents 58.0 58.0 aRPD depth 16.5 74.6 Mean particle size 12.5 87.0 Sediment penetrability 9.4 96.5 Northeastern Naturalist 32 T.G. Gerwing, A.M. Allen Gerwing, D. Drolet, M.A. Barbeau, and D.J. Hamilton 2015 Vol. 22, Monograph 12 in Gerwing et al. (2013) and Gerwing et al. (2015a). Mean particle size (12%) and sediment penetrability (9%) contributed less to the variation than the other variables among all samples. Differences between SIMPER and dbRDA analyses are likely a result of within-site patchiness of sediment condition s. Conclusion We examined biotic and abiotic features of intertidal mudflats at 8 intertidal mudflats, spanning the entire upper Bay of Fundy, Canada. The patterns reported here are an essential first step in the development of predictive models and can inform the design of manipulative experiments to investigate relationships within and between biotic and abiotic components of this ecosystem. We are currently working to quantify driving forces (top-down predation, bottom-up resources, abiotic factors, and pre- versus post-settlement processes) behind these patterns by further analysis of our large-scale mensurative study (e.g. T.G. Gerwing et al., unpubl. data), and planning and implementing manipulative studies. Acknowledgments We thank A. Black, S. Blacquière Bringloe, L.K. Boone, T.T. Bringloe, M.R.S. Coffin, M.E. Coulthard, J.R. Doucet, D. Ellis, A.L. Einfeldt, M.A. Hebert, X. Hu, K.G. Kennedy, D. LeBrech, E.C. MacDonald, C.B.A. Macfarlane, S.M. MacNeil, A. Mayberry, J. Murray, J. Oak, C. Ochieng, J.T. Quinn, D.W. Schneider, K.C. Shim, and J. Wo for assistance with field work and/or processing many samples. We also thank K. Haralampides and D. Connor, Department of Civil Engineering at the University of New Brunswick (UNB), for help with sediment analyses; Mount Allison University (MTA), and Acadia Centre for Estuarine Research, Acadia University, for use of their facilities; the mudflat ecology group at the UNB, MTA and Carleton University for many discussions; our partners Canadian Wildlife Services, Environment Canada; the Departments of Natural Resources in New Brunswick and in Nova Scotia; and the Nature Conservancy of Canada for useful feedback. K.R. Clarke gave valuable advice regarding PRIMER analysis. This study was funded by the Natural Sciences and Engineering Research Council of Canada (a Strategic Project Grant and Discovery grants to M.A. Barbeau and D.J. Hamilton), New Brunswick Wildlife Trust Fund grants to M.A. Barbeau, Mprime (a Canadian Network of Centres of Excellence for the mathematical sciences), Science Horizons Internship Program (Environment Canada), and the Canada Summer Job Program. T.G. 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Drolet, M.A. Barbeau, and D.J. Hamilton 2015 Vol. 22, Monograph 12 Rossi, F., P.M.J. Herman, and J.J. Middelburg. 2004. Interspecific and intraspecific variation of 13C and 15N in deposit- and suspension-feeding bivalves (Macoma balthica and Cerastoderma edule): Evidence of ontogenetic changes in feeding mode of Macoma balthica. Limnology and Oceanography 49:408–414. Savoie, A. 2009. Effects of density of the amphipod Corophium volutator on sediment properties. B.Sc. Honors Thesis. University of New Brunswick, Fredericton, NB, Canada. Scaps, P. 2002. A review of the biology, ecology, and potential use of the Common Ragworm Hediste diversicolor (OF Müller) (Annelida: Polychaeta). Hydrobiologia 470:203–218. Scholz, B., and G. Liebezeit. 2012. Microphytobenthic dynamics in a Wadden Sea intertidal flat. Part I: Seasonal and spatial variation of diatom communities in relation to macronutrient supply. European Journal of Phycology 47:105–119. Shepherd, P., and J. Boates. 1999. 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Benthic communities at two remote Pacific coral reefs: Effects of reef habitat, depth, and waveenergy gradients on spatial patterns. PeerJ 1:e81. Wilson, W., Jr. 1988. Shifting zones in a Bay of Fundy soft-sediment community: Patterns and processes. Ophelia 29:227–245. Wilson, W., Jr. 1989. Predation and the mediation of intraspecific competition in an infaunal community in the Bay of Fundy. Journal of Experimental Marine Biology and Ecology 132:221–245. Word, J.Q. 1979. Classification of benthic invertebrates into infaunal trophic-index feeding groups. Coastal Water Research Project Biennial Report 1980:103–121. Yeo, R.K. 1977. Animal–sediment relationships and the ecology of the intertidal mudflat environment, Minas Basin, Nova Scotia. M.Sc. Thesis. McMaster University, Hamilton, ON, Canada. Northeastern Naturalist Vol. 22, Monograph 12 T.G. Gerwing, A.M. Allen Gerwing, D. Drolet, M.A. Barbeau, and D.J. Hamilton 2015 37 Appendix 1. Results of a SIMPER analysis showing percent contribution (%) of each taxon to the dissimilarity between consecutive pairs of sampling rounds for the invertebrate community (4th-root transformed density data) on 8 intertidal mudflats in the upper Bay of Fundy (see Fig. 1 for site names that correspond to site codes). * = a taxon with a consistent contribution to round differences (i.e., a value with an average dissimilarity/standard deviation of dissimilarities ≥1). For each entry, the first value is for 2009–2010, and the second value for 2010–2011. 1 = early June, 2 = late June, 3 = mid-July, 4 = early August, 5 = late August/early September, 6 = October, 7 = December, and 8 = March (for more precise dates, see Fig. 2). Site Taxon 1–2 2–3 3–4 4–5 5–6 6–7 7–8 SP Cirratulidae 11.0*, 12.5* 20.5*, 12.2* 17.4*, 14.0* 11.2*, 19.2* 16.2*, 14.2* 15.3*, 15.2* 12.1*, 14.9* Spionidae 10.8*, 10.4* 8.5*, 9.5* 8.6*, 8.8* 9.5*, 10.2* 7.9*, 7.1 20.2*, 6.1 17.6*, 7.0* Capitellidae 7.0.0, 3.3* 6.2*, 2.9* 5.4*, 2.9* 3.8*, 5.4 5.8, 6.2 12.9*, 5.6* 14.8*, 5.5* Maldanidae 0.0, 0.0 0.0, 0.0 0.0, 1.3 0.0, 1.3 0.0, 0.0 0.0, 0.0 0.4, 0.6 Nereididae 0.0, 0.5 4.2, 0.5 4.2, 0.0 1.8, 0.0 1.2, 0.5 0.0, 1.2 0.0, 0.6 Nephtyidae 7.8*, 6.3 7.2*, 6.5 6.5*, 3.2 4.9, 0.0 4.3, 3.8 2.4, 8.1 3.0.0, 7.5 Phyllodocidae 8.9*, 6.5 4.9*, 7.5* 4.1, 6.0 3.7*, 5.2 4.1, 7.8 5.1, 7.5 3.9*, 6.7 Glyceridae 0.0, 3.4 1.4, 3.5 4.4, 1.7 5.5*, 0.9 5.3, 1.3 3.2, 1.1 0.7, 0.6 Goniadidae 0.5, 1.9 0.0, 1.4 0.4, 1.4 2.9, 1.8 3.2, 3.9 0.8, 4.1 0.0, 0.0 Orbiniidae 0.0, 6.3 1.0.0, 9.8* 0.9, 10.2* 0.0, 5.9 0.0, 5.5 0.5, 3.5 5.9, 6.1 C. volutator 15.4*, 5.3 14.2*, 6.6 16.5*, 7.3 17.2*, 2.8 8.7, 3.7 4.1, 5.5 4.3, 4.4 Ostracoda 12.4*, 14.3* 10.3*, 11.9* 10.4*, 16.3* 16.9*, 16.8* 15.5*, 14.8* 11.6*, 18.9* 12.9*, 17.7* Copepoda 15.4*, 15.6* 10.8*, 14.3* 10.9*, 13.7* 10.8*, 15.0* 12.6*, 12.7* 14.7*, 13.7* 13.6*, 15.2* Macoma spp. 8.6*, 9.9 8.7*, 9.3 7.9*, 9.2* 8.3*, 10.5* 9.8*, 10.5* 9.3*, 6.4 9.5*, 13.5 N. obsoletus 2.2*, 3.9* 2.1*, 4.2* 2.6*, 4.1* 3.5*, 4.9* 5.5*, 8.1* 0.0, 3.3 1.2, 0.2 MC Cirratulidae 3.6, 7.8 2.7, 8.3 3.7, 9.2 5.1, 9.9 4.9, 9.8 4.3, 13.2* 4.2, 12.3* Spionidae 4.6, 9.9 4.2, 8.6 0.0, 9.7 11.2*, 14.6* 9.4, 13.7* 8.3, 15.2* 6.8, 13.7* Capitellidae 0.0, 0.6 0.0, 1.3 0.0, 0.8 0.0, 0.0 0.0, 0.5 0.0, 2.2 0.0, 2.3 Maldanidae 0.0, 0.7 0.5, 0.0 0.5, 0.0 0.0, 0.0 0.6, 0.4 1.4, 0.5 0.7, 0.8 Nereididae 9.9*, 10.4 10.9*, 8.3 14.2*, 9.1 9.2, 8.2 9.2, 7.6 11.2, 8.4 16.9, 11.3 Nephtyidae 7.3. 7.9 6.1, 7.3 5.4, 6.5 6.8, 5.9 4.9, 5.6 6.3, 8.5 7.4, 8.1 Phyllodocidae 6.7, 5.4 5.6, 5.4 7.1, 6.5 8.5*, 9.3* 7.4, 8.6* 11.1*, 10.4* 10.9*, 11.8* Glyceridae 0.0, 0.0 0.0, 0.0 0.0, 0.0 0.0, 0.0 0.0, 0.0 0.0, 0.0 0.0, 0.0 Goniadidae 0.0, 0.0 0.0, 0.0 0.0, 0.0 0.0, 0.0 0.5, 0.0 0.6, 0.0 0.0, 0.0 Orbiniidae 0.0, 0.0 0.0, 0.0 0.0, 0.0 0.0, 0.0 0.0, 0.0 0.0, 0.0 0.0, 0.0 Northeastern Naturalist 38 T.G. 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Hamilton 2015 Vol. 22, Monograph 12 Site Taxon 1–2 2–3 3–4 4–5 5–6 6–7 7–8 C. volutator 25.0*, 15.6* 21.1, 24.7* 18.2, 16.6 23.1*, 16.7* 24.2*, 23.9* 17.9*, 13.7* 16.3*, 12.6* Ostracoda 3.3, 1.6 2.9, 2.6 1.8, 5.6 5.3, 5.6 4.6, 4.2 3.6, 3.0 2.1, 5.2 Copepoda 23.6*, 23.4* 27.8*, 20.7* 25.8, 23.4* 18.6, 18.9* 23.1*, 15.8* 23.2*, 12.0* 19.3*, 12.1* Macoma spp. 13.2, 13.2 13.8*, 9.5 12.5*, 9.3 8.8, 8.5 7.7, 7.0 9.9, 6.9 14.7, 9.1 N. obsoletus 2.8, 3.5* 4.4, 3.6* 3.9*, 3.2 3.4*, 2.4* 3.6*, 2.8* 2.2, 5.9* 0.6*, 0.6* AV Cirratulidae 10.1*, 11.2* 10.6*, 10.9* 9.7*, 9.9* 9.4*, 10.3* 6.9*, 11.9* 5.4, 13.5* 7.9, 13.3* Spionidae 8.5*, 13.1* 8.9*, 11.9* 8.8*, 9.0 7.7*, 10.0* 10.5*, 10.2* 10.8*, 8.7* 12.2*, 9.3 Capitellidae 8.9*, 10.7* 8.0*, 8.9* 7.3*, 9.0* 9.4*, 8.8* 8.6*, 8.5* 10.6*, 8.9* 12.4*, 10.0* Maldanidae 0.0, 3.2 1.5, 3.9 1.4, 2.8 0.7, 3.6 0.7, 3.5 0.0, 2.6 2.4, 5.2 Nereididae 0.8, 2.6 7.2, 1.7 6.6, 2.3 1.4, 1.7 1.3, 0.0 1.6, 0.0 0.9, 0.0 Nephtyidae 9.1*, 8.2* 12.5*, 8.7* 11.6*, 11.2* 10.8*, 11.4* 11.9*, 11.4* 12.4*, 9.9* 13.7, 6.5 Phyllodocidae 7.7, 7.3 7.2*, 6.9* 6.3*, 6.3* 5.4, 6.5* 6.9*, 6.9* 5.4, 7.6* 5.7, 7.9* Glyceridae 0.0, 0.0 0.0, 0.0 0.0, 0.0 0.0, 0.0 0.0, 0.0 0.0, 0.0 0.0, 0.0 Goniadidae 0.0, 0.0 0.0, 0.0 0.4, 0.0 0.4, 0.0 0.0, 0.3 0.0, 0.4 0.0, 0.0 Orbiniidae 0.0, 0.4 0.5, 1.5 0.5, 1.4 0.3, 1.3 0.2, 1.4 0.3, 1.3 0.4, 3.9 C. volutator 21.8*, 12.7* 11.8*, 16.3* 16.2*, 16.5* 20.3*, 17.0* 16.7*, 16.6* 18.1*, 14.1* 8.9*, 12.4* Ostracoda 9.7*, 11.5* 9.7*, 8.8* 9.9*, 12.3* 10.4*, 12.2* 13.9*, 12.4* 13.6*, 10.8* 16.6, 13.6* Copepoda 15.4*, 10.7* 12.8*, 12.6* 12.9*, 11.9* 14.8*, 9.8* 11.5*, 9.6* 14.1*, 13.8* 13.3*, 12.1* Macoma spp. 4.9, 5.2 5.9, 4.8 5.9*, 4.9 6.2*, 4.9 6.5, 3.5 4.9, 5.0 4.7, 5.1 N. obsoletus 3.2*, 3.5* 3.2*, 3.0* 2.6*, 2.3 2.8*, 2.5 4.2*, 3.8* 2.9, 3.4* 0.7, 0.7 MN Cirratulidae 0.0, 1.1 0.0, 0.6 0.0, 0.0 0.0, 0.0 0.0, 0.6 0.7, 1.3 0.7, 1.3 Spionidae 13.6*, 14.8* 17.9*, 14.2* 16.7*, 12.3* 14.0*, 11.7* 16.1*, 8.3* 17.2*, 5.9 16.2*, 7.1 Capitellidae 9.9*, 7.5 8.9*, 8.3 7.7, 8.4* 7.1, 8.7 7.1, 8.7* 5.9, 10.3* 3.2, 10.7 Maldanidae 0.0, 0.0 0.0, 0.0 0.0, 0.0 0.0, 0.0 0.0, 0.0 0.0, 0.0 0.0, 0.0 Nereididae 11.7*, 11.1* 12.0*, 10.9* 12.1*, 11.6* 11.8*, 12.8* 11.7*, 11.9* 9.6, 10.6 9.7, 10.9 Nephtyidae 7.1, 10.5* 7.3, 12.9* 9.7*, 11.4* 9.0.0, 9.8 8.3, 7.6 8.2, 6.1 7.3, 8.3 Phyllodocidae 9.2*, 9.3* 10.6*, 11.4* 11.1*, 9.7* 9.2*, 7.3 9.8*, 9.6* 9.9*, 11.5* 7.6, 14.8* Glyceridae 0.0, 0.0 0.6, 0.0 0.6, 0.0 0.0, 0.0 0.0, 0.0 0.6, 0.0 0.6, 0.0 Goniadidae 0.7, 0.6 0.0, 0.6 0.0, 0.0 0.0, 0.0 0.0, 0.0 0.0, 0.0 0.0, 0.0 Orbiniidae 0.0, 0.0 1.2, 0.0 1.2, 0.0 0.0, 0.0 0.0, 0.0 0.0, 0.0 0.0, 0.0 Northeastern Naturalist Vol. 22, Monograph 12 T.G. 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Hamilton 2015 39 Site Taxon 1–2 2–3 3–4 4–5 5–6 6–7 7–8 C. volutator 16.3*, 13.1* 11.1*, 10.6* 9.6*, 13.8* 11.2*, 16.0* 11.2*, 24.5* 8.5*, 16.9 12.8*, 16.9* Ostracoda 4.8, 7.6 5.9, 5.7 9.3, 9.4 14.2*, 9.8* 14.9*, 5.9 11.2, 3.1 10.1, 2.5 Copepoda 15.4*, 13.1* 15.2, 11.6* 12.3, 10.5* 13.0*, 9.8* 8.0*, 9.9 16.1*, 22.7* 21.7, 18.1* Macoma spp. 6.8, 7.1 5.5, 8.8 6.5, 9.3* 7.0.0, 9.8* 7.7, 7.7 10.2*, 8.1 10.0*, 9.3 N. obsoletus 4.3*, 4.1* 3.9*, 4.5* 3.0*, 3.7* 3.3*, 4.3* 5.1*, 5.1* 1.9, 3.6 0.0, 0.0 PC Cirratulidae 0.0, 1.5 0.0, .08 0.0, .06 0.0, .07 0.0, .06 0.0, .07 0.0, .08 Spionidae 15.9*, 17.6* 17.4*, 16.5* 10.7*, 16.8* 12.8*, 17.9* 13.8*, 16.0* 16.7*, 13.4* 15.9*, 13.8* Capitellidae 7.0, 7.5 6.9, 8.1 6.7, 7.9 7.8, 7.4 7.7, 6.6 4.8, 6.8 4.9, 4.7 Maldanidae 0.0, 0.0 0.0, 0.0 0.0, 0.0 0.0, 0.0 0.0, 0.0 0.0, 0.0 0.0, 0.0 Nereididae 3.1, 8.1 7.2, 12.3* 13.5*, 14.3* 13.7*, 16.2* 11.7*, 12.9* 12.2*, 12.7* 9.1*, 12.1* Nephtyidae 10.9, 14.3* 12.4*, 14.3* 12.8*, 14.8* 13.1*, 16.3* 15.0*, 13.3* 16.9*, 16.5* 12.3, 18.7* Phyllodocidae 11.2*, 11.3* 12.4*, 12.3* 10.5*, 11.4* 9.8*, 11.3* 9.9*, 8.2* 11.9*, 9.9* 11.4*, 11.8* Glyceridae 0.0, 0.0 0.0, 0.0 0.0, 0.0 0.7, 0.0 0.7, 0.0 0.0, 0.0 0.0, 0.0 Goniadidae 0.0, 0.0 0.0, 0.0 0.0, 0.0 0.0, 0.0 0.0, 0.0 0.0, 0.0 0.0, 0.0 Orbiniidae 0.0, 0.0 0.0, 0.0 0.0, 0.0 0.0, 0.0 0.0, 0.0 0.0, 0.0 0.0, 0.0 C. volutator 23.7*, 13.9* 13.9*, 11.8* 11.7*, 8.8* 5.7*, 9.8* 7.6*, 24.8 9.1*, 14.6* 13.1*, 15.1* Ostracoda 3.2, 6.7 2.1, 3.2 3.9, 3.7 8.3, 3.4 8.2, 1.1 2.0, .07 3.6, 0.7 Copepoda 19.9*, 11.4* 17.4*, 12.8* 17.0*, 13.4* 15.5*, 7.6* 13.2*, 7.7 14.7*, 16.3 19.3, 18.2 Macoma spp. 2.9, 5.5 7.8, 5.6 10.2, 6.4 9.4*, 7.4 10.0*, 6.5 10.6, 6.6 10.4*, 3.9 N. obsoletus 2.2, 2.3 2.5, 2.4 3.1, 1.8 3.2*, 2.1 2.1, 2.3 1.2, 2.0 0.0, 0.3 GA Cirratulidae 0.0, 1.6 0.0, 1.5 2.9, 1.2 3.6, 1.7 1.3, .05 1.2, 1.4 9.6, 3.3 Spionidae 8.9*, 12.7* 20.2*, 17.1* 18.8*, 14.6* 14.8*, 15.1 13.0*, 14.5* 10.6*, 11.0* 18.3*, 11.7* Capitellidae 6.9, 7.8 6.4, 7.3 6.4, 7.8 7.2, 7.5 7.3, 5.7 4.8, 6.1 3.2, 5.4 Maldanidae 0.0, 0.0 0.9, 0.0 0.9, 0.0 0.0, 0.0 0.0, 0.0 0.0, 0.0 0.0, 0.0 Nereididae 7.8, 5.6 7.9*, 9.9* 7.3, 8.9* 3.4, 6.9 1.9, 5.2 4.5, 3.3 4.7, 3.6 Nephtyidae 2.9, 2.0 2.9, 1.3 3.2, 0.5 3.6, 1.6 2.5, 2.1 0.7, 4.6 3.7, 4.5 Phyllodocidae 13.5, 8.8 8.7*, 8.8* 8.3*, 8.6 6.0, 7.4 5.0, 8.0* 10.3*, 8.6* 9.6*, 9.8* Glyceridae 0.0, 0.0 0.0, 0.0 0.0, 1.1 0.0, 1.1 0.0, 0.0 0.0, 0.0 0.0, 0.0 Goniadidae 0.0, 0.0 0.0, 0.0 0.0, 0.0 0.0, 0.0 0.0, 0.0 0.0, 0.0 0.0, 0.0 Orbiniidae 0.0, 0.0 0.0, 0.0 0.0, 0.0 0.0, 0.0 0.0, 0.0 0.0, 0.0 0.0, 0.0 Northeastern Naturalist 40 T.G. Gerwing, A.M. Allen Gerwing, D. Drolet, M.A. Barbeau, and D.J. Hamilton 2015 Vol. 22, Monograph 12 Site Taxon 1–2 2–3 3–4 4–5 5–6 6–7 7–8 C. volutator 11.7, 18.9* 9.2, 17.4* 9.2*, 16.1* 10.6*, 16.7* 14.4*, 16.8* 16.3*, 13.9* 13.40*, 15.6* Ostracoda 19.5*, 14.9* 14.8*, 8.9* 16.2*, 13.8* 23.4*, 16.4* 20.7*, 23.4* 17.3*, 20.8* 16.9*, 19.4* Copepoda 22.6, 13.6 13.4*, 8.4* 14.8*, 14.2* 15.3*, 13.9* 18.0*, 9.7* 14.0*, 15.4* 8.5*, 11.3 Macoma spp. 1.4, 9.7 11.9*, 15.1* 8.7*, 8.9* 9.5*, 7.6* 12.8*, 10.7* 12.3*, 10.0* 12.1*, 11.8* N. obsoletus 4.7*, 4.5* 3.5*, 4.3* 3.4*, 4.2* 2.7*, 4.1* 3.0*, 3.4* 7.9*, 4.9* 0.0, 3.8* DF Cirratulidae 1.9, 5.4 0.9, 5.5 3.3, 7.1 6.5, 7.8 4.6, 5.5 2.1, 7.7 5.4, 9.4 Spionidae 16.2*, 14.8* 16.6*, 14.6* 12.9*, 15.0* 12.4, 15.8* 15.9*, 13.7* 16.1*, 15.4* 15.3, 15.8* Capitellidae 7.7, 5.3 8.5, 5.4 7.5, 4.3 6.3, 4.9 3.6, 5.3 3.7, 4.8 2.3, 2.4 Maldanidae 0.0, 0.0 0.0, 0.0 0.0, 0.0 0.0, 0.0 0.0, 0.0 0.0, 0.7 0.0, 0.7 Nereididae 8.3, 5.3 10.7*, 8.6 12.0*, 10.0* 12.6*, 10.8* 11.5, 9.1* 9.6, 8.2 7.8, 6.9 Nephtyidae 7.9, 4.1 9.7, 3.4 10.8, 3.4 5.6, 3.2 3.4, 5.2 6.9, 6.2 6.9, 4.1 Phyllodocidae 11.1, 9.2* 11.1*, 10.5* 12.9*, 10.8* 9.2, 7.6 10.5, 9.3* 13.3*, 11.3* 12.0*, 12.6* Glyceridae 0.0, 0.0 0.0, 0.0 0.0, 0.0 0.0, 0.0 0.0, 0.0 0.0, 0.0 0.0, 0.0 Goniadidae 0.0, 0.0 0.0, 0.6 0.0, 0.6 0.0, 0.6 0.0, 0.6 0.0, 0.0 0.0, 0.0 Orbiniidae 0.0, 0.0 0.0, 0.0 1.3, 0.0 1.4, 0.0 0.0, 0.0 0.0, 0.0 0.0, 0.0 C. volutator 15.4*, 18.3* 10.3, 15.0* 7.6, 11.2* 3.8*, 9.1* 6.0.0, 25.3* 12.8, 16.8* 16.2*, 18.6* Ostracoda 12.5*, 12.2* 12.6*, 12.6* 13.5*, 12.4* 16.7*, 13.7* 18.1*, 7.7 14.0.0, 9.9* 13.4*, 11.9* Copepoda 6.5, 12.1* 4.9, 9.9* 3.4*, 10.4* 9.5, 10.4* 6.9, 9.7* 6.5, 10.4* 7.1, 8.5* Macoma spp. 11.1, 11.1 12.3*, 10.7* 12.0*, 11.3* 10.5, 12.5* 13.9*, 7.5 14.2*, 8.1 13.6*, 9.3 N. obsoletus 1.4, 2.3 2.4, 3.2* 2.7, 3.6* 5.7*, 3.6* 5.4*, 1.2 0.9, 0.5 0.0, 0.0 MP Cirratulidae 4.2, 9.5 3.2, 12.2* 5.7, 12.3* 9.2, 10.1 8.8, 8.5 10.0.0, 12.3 14.7*, 15.1* Spionidae 17.0*, 14.7* 16.8*, 12.5* 12.6*, 9.9* 16.0*, 10.2* 15.3*, 10.6* 16.3*, 13.8* 14.4*, 11.5 Capitellidae 3.7, 1.1 7.2, 1.8 7.2, 1.8 2.1, 1.3 1.6, 0.8 1.7, 0.5 1.3, 1.5 Maldanidae 0.0, 0.0 0.0, 0.0 0.0, 0.0 0.0, 0.0 0.0, 0.0 0.0, 0.0 0.0, 0.0 Nereididae 7.1, 5.8 10.0*, 7.3 8.9*, 8.5* 8.8*, 8.9* 6.5, 7.7 7.2, 7.9 7.5, 6.3 Nephtyidae 6.9, 7.5 6.8*, 7.4 7.5*, 7.0 8.9*, 7.6 8.9*, 6.6 10.5, 6.5 9.6, 6.8 Phyllodocidae 7.9, 7.0 7.5*, 7.8* 7.2, 7.5 8.1*, 8.0* 7.9, 7.7 7.3, 7.4 8.0*, 8.1* Glyceridae 0.5, 0.4 0.0, 0.4 0.0, 0.0 0.0, 0.6 0.0, 0.5 0.4, 1.8 0.4, 1.8 Goniadidae 0.0, 0.0 0.0, 0.4 0.0, 0.4 0.0, 0.5 0.0, 0.5 0.0, 0.0 0.0, 0.0 Orbiniidae 0.0, 0.0 0.8, 0.0 0.8, 0.0 0.0, 0.0 0.0, 0.0 0.7, 0.0 1.4, 0.0 Northeastern Naturalist Vol. 22, Monograph 12 T.G. Gerwing, A.M. Allen Gerwing, D. Drolet, M.A. Barbeau, and D.J. Hamilton 2015 41 Site Taxon 1–2 2–3 3–4 4–5 5–6 6–7 7–8 C. volutator 14.9*, 16.2* 13.6*, 16.6* 16.7*, 23.2* 15.8*, 22.6* 17.9*, 28.3* 16.5*, 16.4* 14.7*, 14.4* Ostracoda 10.4, 13.4* 10.2*, 10.4 9.6*, 9.4* 11.1*, 9.6* 12.5*, 5.9 7.1, 6.5 8.0, 8.2 Copepoda 15.7, 11.7* 11.1, 12.1* 13.0*, 7.3* 8.8*, 7.5* 10.6*, 10.8* 10.7*, 13.1* 10.8*, 13.2 Macoma spp. 7.8, 9.6* 9.7*, 8.3* 7.9*, 9.6* 8.3*, 10.2* 7.4*, 9.5* 8.9*, 10.6* 9.0*, 10.9* N. obsoletus 3.8, 3.2* 3.1*, 2.8* 2.9, 2.9* 2.9*, 2.9* 2.6, 2.5 2.5*, 3.2 0.1, 2.1 Northeastern Naturalist 42 T.G. Gerwing, A.M. Allen Gerwing, D. Drolet, M.A. Barbeau, and D.J. Hamilton 2015 Vol. 22, Monograph 12 Appendix 2. Results of a SIMPER analysis showing percent contribution (%) of each taxon to the dissimilarity in invertebrate community (4th-root transformed density data) between each pair of sites (pooled over sampling rounds). See Figure 1 for the full names of the 8 mudflats in the upper Bay of Fundy. * = a taxon with a consistent contribution to site differences (i.e., a value with an average dissimilarity/standard deviation of dissimilarities ≥ 1). For each entry, the first value is for 2009–2010, and the second value for 201 0–2011. Taxon SP–AV AV–MC SP–MC SP–MN AV–MN MC–MN MN–PC Cirratulidae 14.0*, 15.2* 5.8, 7.9* 14.75*, 14.98* 16.6*, 18.1* 5.9, 8.0 2.0, 5.2 0.1, 0.7 Spionidae 8.6*, 6.4* 7.7*, 10.0* 9.83*, 8.17* 8.8*, 8.0* 8.5*, 10.3* 10.4*, 9.7* 14.2*, 14.9* Capitellidae 9.0*, 9.1* 8.7*, 9.6* 13.01*, 14.86* 12.4*, 13.1* 8.7*, 9.1* 3.9, 5.2 6.6, 7.1 Maldanidae 0.4, 1.7 0.6, 1.7 0.13, 0.21 0.0, 0.1 0.5, 1.8 0.2, 0.2 0, 0 Nereididae 1.3, 0.6 8.5*, 9.8* 6.17*, 8.02* 4.1, 3.7 5.7, 4.9 10.6*, 11.4* 10.2*, 10.2* Nephtyidae 9.6*, 11.7* 12.7*, 11.8* 3.06, 2.83 3.5, 3.5 12.8*, 12.2* 5.7, 6.5 9.9, 11.5 Phyllodocidae 9.1*, 8.3* 5.1, 5.4* 9.60*, 8.02* 9.8*, 7.3* 5.6*, 5.8* 6.6*, 7.9* 11.1*, 9.3* Glyceridae 1.2, 0.6 0.0, 0.0 1.12, 0.47 1.2, 0.5 0.1, 0.0 0.1, 0.0 0.2, 0.0 Goniadidae 0.4, 0.7 0.1, 0.1 0.36, 0.52 0.4, 0.6 0.1, 0.1 0.1, 0.1 0.1, 0.1 Orbiniidae 0.8, 2.7 0.1, 0.7 0.60, 1.90 0.7, 2.0 0.2, 0.8 0.1, 0.0 0.1, 0.0 C. volutator 11.2*, 9.7 14.4*, 11.2* 9.89*, 8.24* 14.6*, 15.1* 16.9*, 15.5* 21.2*, 19.9* 13.9*, 19.6* Ostracoda 9.4*, 10.9* 10.6*, 10.7* 11.72*, 13.76* 11.4*, 13.9* 10.5*, 11.3* 5.6, 4.0 7.3, 4.3 Copepoda 17.3*, 14.3* 14.6*, 9.9* 12.50*, 8.82* 9.3*, 6.9* 16.9*, 13.0* 19.1*, 13.9 15.5*, 12.3 Macoma spp. 5.4, 4.9 8.2*, 8.7* 5.64*, 6.58* 5.3, 4.3 4.7, 4.2 11.6*, 12.8* 7.5, 6.3 N. obsoletus 2.3*, 3.2* 2.8, 2.7 1.63*, 2.62* 1.9*, 2.8* 2.9*, 2.9* 2.9, 3.2* 3.3*, 3.7* Taxon MN–GA PC–GA GA–DF GA–MP DF–MP PC–DF PC–MP Cirratulidae 1.2, 0.8 1.2, 0.8 2.4, 3.2 5.7, 6.9 6.6, 9.3 1.6, 3.8 5.7, 7.7 Spionidae 12.4*, 13.8* 11.8*, 10.6* 13.7*, 12.7* 14.2*, 10.4* 15.5*, 12.9* 14.2*, 14.3* 14.7*, 12.2* Capitellidae 4.3, 5.1 3.8, 4.1 3.7, 4.2 3.5, 3.4 3.4, 2.6 4.8, 4.9 4.2, 3.5 Maldanidae 0.1, 0.0 0.1, 0.0 0.1, 0.1 0.1, 0.0 0.0, 0.1 0.0, 0.1 0.0, 0.0 Nereididae 6.2, 6.1 4.7, 5.9 5.2, 5.2 5.8, 5.2 7.5, 6.9 7.7, 9.1 7.5, 7.9 Nephtyidae 3.8, 4.5 5.8, 7.4 3.3, 2.4 5.5, 4.6 6.9, 5.9 8.6, 10.8 8.7, 9.5 Phyllodocidae 6.8*, 6.6* 6.9*, 6.2* 7.5*, 7.1* 6.9*, 7.3* 8.3*, 8.8* 9.7*, 9.4* 8.5*, 7.9* Glyceridae 0.1, 0.1 0.1, 0.1 0.0, 0.1 0.1, 0.4 0.1, 0.3 0.1, 0.0 0.2, 0.3 Goniadidae 0.1, 0.0 0.0, 0.0 0.0, 0.1 0.0, 0.1 0.0, 0.2 0.0, 0.1 0.0, 0.1 Orbiniidae 0.1, 0.0 0.0, 0.0 0.1, 0.0 0.2, 0.0 0.4, 0.0 0.1, 0.0 0.3, 0.0 C. volutator 21.2*, 15.3* 20.0*, 17.0* 17.6*, 16.7* 13.2*, 15.4* 17.8*, 21.4 17.6*, 19.1* 19.2*, 22.4* Northeastern Naturalist Vol. 22, Monograph 12 T.G. Gerwing, A.M. Allen Gerwing, D. Drolet, M.A. Barbeau, and D.J. Hamilton 2015 43 Taxon MN–GA PC–GA GA–DF GA–MP DF–MP PC–DF PC–MP Ostracoda 24.1*, 27.5* 25.6*, 27.5* 23.5*, 26.7* 23.1*, 25.3* 10.3*, 9.5* 10.1, 8.4 7.7, 7.0 Copepoda 10.2, 9.6* 10.7, 10.2 11.5*, 9.7* 10.7, 9.7* 11.2*, 10.1* 13.3*, 10.6* 12.1*, 10.7* Macoma spp. 6.8*, 7.7* 6.9*, 7.4* 8.7*, 8.6* 8.2*, 8.3* 9.6*, 9.5* 10.5*, 7.7 9.3*, 8.5* N. obsoletus 2.7*, 2.9* 2.5*, 2.8* 2.8*, 3.2* 2.7*, 2.9* 2.3, 2.5 1.7, 1.7 2.2, 2.3 Taxon MN–DF MN–MP SP–PC SP–GA SP–DF SP–MP AV–PC Cirratulidae 1.6, 3.8 5.7, 7.6 16.9*, 17.3* 18.5*, 21.8* 17.1*, 17.9* 15.6*, 16.0* 5.9, 8.2 Spionidae 15.0*, 13.6* 15.7*, 13.5* 8.1*, 6.8* 10.0*, 6.4* 8.7*, 7.0* 9.3*, 6.1* 8.5*, 9.2* Capitellidae 5.4, 6.7 4.6, 5.2 12.9*, 14.0* 14.7*, 16.8* 14.1*, 15.7* 14.1*, 16.8* 8.9*, 9.9* Maldanidae 0.0, 0.1 0.0, 0.0 0.1, 0.1 0.1, 0.1 0.0, 0.2 0.0, 0.1 0.5, 1.8 Nereididae 8.7*, 8.9 8.2*, 7.9 3.0, 3.6 2.1, 2.1 3.2, 2.6 3.9, 2.9 4.2, 5.0 Nephtyidae 5.9, 6.7 7.1, 7.1 4.7, 3.9 3.2*, 2.4 3.4, 2.4 4.6, 3.7 12.2*, 10.9* Phyllodocidae 9.3*, 9.4* 7.3*, 7.8* 7.6*, 6.1* 9.0*, 7.6* 8.4*, 7.1* 9.3, 8.8* 6.8*, 5.9* Glyceridae 0.1, 0.0 0.2, 0.3 1.3, 1.9 1.4, 0.7 1.3, 0.5 1.4, 0.7 0.1, 0.0 Goniadidae 0.1, 0.2 0.1, 0.2 0.4, 0.5 0.4, 0.7 0.4, 0.6 0.4, 0.6 0.0, 0.0 Orbiniidae 0.2, 0.0 0.4, 0.0 0.7, 0.5 0.8, 2.4 0.8, 2.1 0.9, 2.2 0.1, 0.8 C. volutator 17.1*, 18.7* 19.2*, 20.3* 14.4*, 17.2* 8.5*, 10.9* 12.7*, 15.9* 10.6*, 12.1* 16.9*, 18.2* Ostracoda 10.7*, 8.8 8.5, 7.5 12.7*, 13.5* 12.5*, 10.3* 11.1*, 12.9* 11.6*, 13.5* 11.2*, 12.1* Copepoda 12.7*, 11.1* 11.3*, 10.7* 10.0*, 7.1* 10.0*, 7.9* 10.7*, 6.9* 10.2*, 7.5* 16.8*, 11.1* Macoma spp. 10.2*, 8.3 8.9*, 8.7* 5.5*, 4.9 6.6*, 6.7* 6.2*, 5.0* 6.2*, 5.8* 4.9, 5.6 N. obsoletus 2.9*, 3.7* 2.8*, 3.2* 1.7*, 2.9* 2.2*, 3.3* 1.9*, 3.2* 1.9*, 3.0* 2.9*, 3.3* Taxon AV–GA AV–DF AV–MP MC–PC MC–GA MC–DF MC–MP Cirratulidae 5.8, 7.9 6.2, 8.4* 7.3, 9.3* 1.9, 4.9 2.4, 4.2 3.0, 6.6 6.2, 9.1 Spionidae 10.4*, 8.1* 10.2*, 9.2* 11.7*, 8.5* 12.1*, 12.5* 12.3*, 13.1* 14.8*, 11.9* 17.0*, 13.6* Capitellidae 8.2*, 9.3* 9.0*, 10.1* 8.7*, 10.4* 3.0, 3.2 2.2, 2.9 1.9, 2.3 1.8, 1.0 Maldanidae 0.5, 1.7 0.4, 1.8 0.4, 1.8 0.2, 0.2 0.2, 0.2 0.2, 0.3 0.2, 0.2 Nereididae 2.5, 2.4 4.2, 3.3 4.8, 3.7 10.8*, 11.0* 8.7*, 10.2* 10.4*, 12.4* 9.7*, 11.8* Nephtyidae 12.7*, 13.6* 13.1*, 13.7* 11.7*, 12.2* 7.8, 8.9 2.9, 3.1 4.8, 4.4 6.6, 6.1 Phyllodocidae 5.8*, 5.7* 6.3*, 5.9* 5.7*, 5.9* 9.1*, 7.7* 6.5*, 6.6* 8.3*, 8.4* 6.8*, 7.0* Glyceridae 0.0, 0.1 0.0, 0.0 0.1, 0.2 0.1, 0.0 0.0, 0.1 0.0, 0.0 0.1, 0.3 Goniadidae 0.0, 0.0 0.0, 0.1 0.0, 0.1 0.1, 0.0 0.0, 0.0 0.1, 0.1 0.05, 0.10 Orbiniidae 0.1, 0.8 0.2, 0.8 0.3, 0.8 0.0, 0.0 0.0, 0.0 0.1, 0.0 0.3, 0.0 C. volutator 12.4*, 11.3* 15.3*, 15.6* 13.9*, 14.1* 20.3*, 21.9* 13.3*, 11.5* 18.5*, 19.5* 16.4*, 17.6* Northeastern Naturalist 44 T.G. Gerwing, A.M. Allen Gerwing, D. Drolet, M.A. Barbeau, and D.J. Hamilton 2015 Vol. 22, Monograph 12 Taxon AV–GA AV–DF AV–MP MC–PC MC–GA MC–DF MC–MP Ostracoda 15.6*, 14.5* 10.1*, 10.4* 9.9*, 10.7 2.8, 2.6 25.1*, 25.6* 8.7, 7.2 6.9, 6.9 Copepoda 17.5*, 15.5* 15.1*, 12.5* 15.7*, 13.2* 18.6*, 11.5* 15.7, 12.5* 17.2*, 12.6* 16.7*, 13.3* Macoma spp. 5.9, 6.3* 7.0*, 4.9 6.8*, 6.2 11.4*, 13.1* 8.2*, 7.6* 9.9*, 11.9* 9.0*, 10.4* N. obsoletus 2.7*, 2.8* 2.9*, 3.2* 2.8*, 3.0* 2.0*, 2.4* 2.5*, 2.5* 2.1*, 2.6* 2.4*, 2.7*