Academia.eduAcademia.edu

Figure 7 – uploaded by Alf Norkko

See full PDFdownloadDownload figure
Fig. 7. Differences in abundances of taxa found in the plots (D, shaded) and the surrounding sediment (A, not shaded) at the three sites over time (as months after addition).

Figure 7 Differences in abundances of taxa found in the plots (D, shaded) and the surrounding sediment (A, not shaded) at the three sites over time (as months after addition).

Related Figures (25)

Fig. 1. The location of the three experimental sites (S1—S3) in Whangapoua Harbour, North Island, New Zealand.
Fig. 1. The location of the three experimental sites (S1—S3) in Whangapoua Harbour, North Island, New Zealand.
Sites that were not significantly different from each other are connected by lines (see Appendix A for full statistical information). Waves=% time waves were present while the site was immersed. Max and mean energy =maximum and mean Uj. Sand transport=% time exceeded the theoretical critical threshold for lifting a grain of sand sized 250 um while the site was immersed. Maximum, mean and minimum ambient conditions found over time at the sites Table 1
Sites that were not significantly different from each other are connected by lines (see Appendix A for full statistical information). Waves=% time waves were present while the site was immersed. Max and mean energy =maximum and mean Uj. Sand transport=% time exceeded the theoretical critical threshold for lifting a grain of sand sized 250 um while the site was immersed. Maximum, mean and minimum ambient conditions found over time at the sites Table 1
The five most dominant taxa found in the ambient sediment at each site on each sampling occasion Values in brackets are mean number per core + S.E.
The five most dominant taxa found in the ambient sediment at each site on each sampling occasion Values in brackets are mean number per core + S.E.
Fig. 2. Changes in communities found at the three sites over time using correspondence analysis. Only two axes are displayed as the amount explained by the 3rd ordination axis was less than half that of the 2nd axis. S1—S3 represents the Ist sampling date of each site, while the arrow represents the last sampling time.
Fig. 2. Changes in communities found at the three sites over time using correspondence analysis. Only two axes are displayed as the amount explained by the 3rd ordination axis was less than half that of the 2nd axis. S1—S3 represents the Ist sampling date of each site, while the arrow represents the last sampling time.
Fig. 3. Means + standard errors of depth of deposited sediment and depth of new sand at the three sites over time (as months after addition). Friedman’s tests (df=2) on the differences, between sites, in both depth of deposited sediment and new sand had p-values of 0.0536 and 0.8224, respectively. The sites show slight but significant differences in immersion time (Table 1), with site 1 emerging from the water on average 37 min later than site 3. There was a clear gradient in wind-wave disturbance between the sites, with ripples on the sediment surface more common at site 1. Generally, site 2 was more similar to site 1 than site 3 in time immersed, amount of time waves was observed and the maximum amount of energy expended on the
Fig. 3. Means + standard errors of depth of deposited sediment and depth of new sand at the three sites over time (as months after addition). Friedman’s tests (df=2) on the differences, between sites, in both depth of deposited sediment and new sand had p-values of 0.0536 and 0.8224, respectively. The sites show slight but significant differences in immersion time (Table 1), with site 1 emerging from the water on average 37 min later than site 3. There was a clear gradient in wind-wave disturbance between the sites, with ripples on the sediment surface more common at site 1. Generally, site 2 was more similar to site 1 than site 3 in time immersed, amount of time waves was observed and the maximum amount of energy expended on the
Fig. 4. Changes in particle size observed over time (as months after addition) in the plots and the surrounding sediment at the three sites. ee anne een ee ne eee anne Ee IE EEE EEE Differences between sites in the composition of the ambient macrobenthic communitie were also observed (Table 2). Although temporal changes were observed, sites | and 2 wer always more similar to each other than to site 3 (Fig. 2). Site 1 was always dominated by th spionid polychaete, Aquilaspio aucklandica, with oligochaetes, the polychaete Lumbrineri brevicirris, and the bivalve Nucula hartvigiana also abundant. Aquilaspio also dominated site 2, with Lysianassidae amphipods, Nereidae polychaetes and Lumbrineris frequent being abundant. In contrast to these two sites, site 3 had few Aquilaspio and instead wa dominated by a number of taxa (Nucula, Lumbrineris, Nereidae and the cockle Austrovenu stutchburyi. Orbinid polychaetes, Scoloplos spp. (consisting of both S. ohlini and § cylindifer), were frequently abundant. Strong differences were observed in the vertics distribution of species within the sediment. Aquilaspio, Austrovenus, Nucula, the cumacea Colurostylis lemurum, the polychaete Capitella, the isopod Exosphaeroma spp. (consistin of both E. chilensis and E. falcatum) and Lumbrineris were found only in the top 2 cm. Th
Fig. 4. Changes in particle size observed over time (as months after addition) in the plots and the surrounding sediment at the three sites. ee anne een ee ne eee anne Ee IE EEE EEE Differences between sites in the composition of the ambient macrobenthic communitie were also observed (Table 2). Although temporal changes were observed, sites | and 2 wer always more similar to each other than to site 3 (Fig. 2). Site 1 was always dominated by th spionid polychaete, Aquilaspio aucklandica, with oligochaetes, the polychaete Lumbrineri brevicirris, and the bivalve Nucula hartvigiana also abundant. Aquilaspio also dominated site 2, with Lysianassidae amphipods, Nereidae polychaetes and Lumbrineris frequent being abundant. In contrast to these two sites, site 3 had few Aquilaspio and instead wa dominated by a number of taxa (Nucula, Lumbrineris, Nereidae and the cockle Austrovenu stutchburyi. Orbinid polychaetes, Scoloplos spp. (consisting of both S. ohlini and § cylindifer), were frequently abundant. Strong differences were observed in the vertics distribution of species within the sediment. Aquilaspio, Austrovenus, Nucula, the cumacea Colurostylis lemurum, the polychaete Capitella, the isopod Exosphaeroma spp. (consistin of both E. chilensis and E. falcatum) and Lumbrineris were found only in the top 2 cm. Th
Fig. 5. Mean sediment characteristics (+ standard errors) observed in the deposited sediment plots (D, shaded) and the ambient sediment (A, not shaded) observed over time (as months after addition) at the three sites. After 10 months, depth of the sediment deposited in the plots was still around 4 cm, although there were differences between the sites (Fig. 3). Site 1 (the site with the most wave action) had less deposited sediment remaining than the other sites. Although depth of the deposited sediment continued to change over the course of the sampling, this difference between the sites was maintained. The amount of new sand found on top of the deposited sediment at each site also varied with time, but more sand was generally found at site 3 (Fig. 3), presumably as at the other two sites, the sand was more likely to be scoured off. More silt and clay were consistently found in the plots than in adjacent sediments within each site (Fig. 4, Appendix B). Over time, some of the deposited sediment formed hard clumps >500 um, resulting in higher proportions of larger particles in the plots than in the ambient sediment. Numbers of burrows found in the deposited sediment were low (3.0 per 0.25 m°), but ay iy by LEN 0D i) , ) i i) i: ey es Cy ee 2. i. i 2 Wl a i aul Oy A . 2. * gy LL a
Fig. 5. Mean sediment characteristics (+ standard errors) observed in the deposited sediment plots (D, shaded) and the ambient sediment (A, not shaded) observed over time (as months after addition) at the three sites. After 10 months, depth of the sediment deposited in the plots was still around 4 cm, although there were differences between the sites (Fig. 3). Site 1 (the site with the most wave action) had less deposited sediment remaining than the other sites. Although depth of the deposited sediment continued to change over the course of the sampling, this difference between the sites was maintained. The amount of new sand found on top of the deposited sediment at each site also varied with time, but more sand was generally found at site 3 (Fig. 3), presumably as at the other two sites, the sand was more likely to be scoured off. More silt and clay were consistently found in the plots than in adjacent sediments within each site (Fig. 4, Appendix B). Over time, some of the deposited sediment formed hard clumps >500 um, resulting in higher proportions of larger particles in the plots than in the ambient sediment. Numbers of burrows found in the deposited sediment were low (3.0 per 0.25 m°), but ay iy by LEN 0D i) , ) i i) i: ey es Cy ee 2. i. i 2 Wl a i aul Oy A . 2. * gy LL a
p-Values from (a) redundancy analysis on sediment characteristics and (b) canonical correspondence analysis on macrofauna using dummy variables to represent treatment, site and treatment*site interactions One thousand random permutations were used to calculate the p-values.
p-Values from (a) redundancy analysis on sediment characteristics and (b) canonical correspondence analysis on macrofauna using dummy variables to represent treatment, site and treatment*site interactions One thousand random permutations were used to calculate the p-values.
Fig. 6. Differences in communities found in the deposited sediment plots (DS1, DS2, DS3) and the surrounding sediment (AS1, AS2, AS3) at the three sites over time using correspondence analysis. Only two axes are displayed as the eigenvalue for the 3rd ordination axis was less than half that of the 2nd axis.
Fig. 6. Differences in communities found in the deposited sediment plots (DS1, DS2, DS3) and the surrounding sediment (AS1, AS2, AS3) at the three sites over time using correspondence analysis. Only two axes are displayed as the eigenvalue for the 3rd ordination axis was less than half that of the 2nd axis.
The five most dominant taxa found in the deposited terrestrial sediment at each site on each sampling occasion The mean abundance per core and standard error are given in brackets.
The five most dominant taxa found in the deposited terrestrial sediment at each site on each sampling occasion The mean abundance per core and standard error are given in brackets.
Results of multiple regression analysis on the sediment characteristics of the experimental plots using wave data as explanatory variables % Explained= model sum of squares divided by total sum of squares. Direction of effect is given as + or — followed by the parameter estimate. Italicised results have p-values 0.05—0.1, all other p-values are <0.05. Waves=% time waves were present. Max and mean energy = maximum and mean Uj. Sand transport=% time that U, exceeded the theoretical critical threshold for lifting a grain of sand sized 250 um. Table 5
Results of multiple regression analysis on the sediment characteristics of the experimental plots using wave data as explanatory variables % Explained= model sum of squares divided by total sum of squares. Direction of effect is given as + or — followed by the parameter estimate. Italicised results have p-values 0.05—0.1, all other p-values are <0.05. Waves=% time waves were present. Max and mean energy = maximum and mean Uj. Sand transport=% time that U, exceeded the theoretical critical threshold for lifting a grain of sand sized 250 um. Table 5
Fig. 8. Differences in abundances of different aggregate groups of taxa found in the plots (D, shaded) and the surrounding sediment (A, not shaded) at the three sites over time (as months after addition).
Fig. 8. Differences in abundances of different aggregate groups of taxa found in the plots (D, shaded) and the surrounding sediment (A, not shaded) at the three sites over time (as months after addition).
Results of multiple regression and canonical correspondence analysis on macrofauna in the deposited sediment plots Direction of effect is given as + or — for the univariate analyses and % explained = model sum of squares divided by total sum of squares. For the community composition, % explained= Ucanonical/Nunconstrained eigenvalues. na=not included in the model. Waves=% time waves were present. Max and mean energy = maximum and mean Us. Sand transport=% time that U,, exceeded the theoretical critical threshold for lifting a grain of sand sized 250 jum. Table 6
Results of multiple regression and canonical correspondence analysis on macrofauna in the deposited sediment plots Direction of effect is given as + or — for the univariate analyses and % explained = model sum of squares divided by total sum of squares. For the community composition, % explained= Ucanonical/Nunconstrained eigenvalues. na=not included in the model. Waves=% time waves were present. Max and mean energy = maximum and mean Us. Sand transport=% time that U,, exceeded the theoretical critical threshold for lifting a grain of sand sized 250 jum. Table 6
Summary of regression analysis on macrofauna found in the deposited sediment plots, showing the relative importance, as percentages of the model sum of squares, of hydrodynamic conditions, sediment characteristics, ambient densities and bioturbation sediment were important for three of the taxa (Aquilaspio, Lumbrineris and Nucula) Food content of the sediment, either as chlorophyll a or % organics, was always ar important variable, except for total number of individuals. Sand transport was importan for Aquilaspio, nereids (mainly juveniles) and the number of rare taxa found. The maximum energy expended on the bed was frequently important and usually resulted ir increased densities. Occasionally, both the maximum and mean energy expended on the bed were important, although these usually operated in opposite directions. Althougl the number of burrows found in the deposited sediment over time showed littk difference between sites, this variable was included in the analysis, it was rarely ar important factor.
Summary of regression analysis on macrofauna found in the deposited sediment plots, showing the relative importance, as percentages of the model sum of squares, of hydrodynamic conditions, sediment characteristics, ambient densities and bioturbation sediment were important for three of the taxa (Aquilaspio, Lumbrineris and Nucula) Food content of the sediment, either as chlorophyll a or % organics, was always ar important variable, except for total number of individuals. Sand transport was importan for Aquilaspio, nereids (mainly juveniles) and the number of rare taxa found. The maximum energy expended on the bed was frequently important and usually resulted ir increased densities. Occasionally, both the maximum and mean energy expended on the bed were important, although these usually operated in opposite directions. Althougl the number of burrows found in the deposited sediment over time showed littk difference between sites, this variable was included in the analysis, it was rarely ar important factor.
(continued on next page) Results of generalized linear modelling on the effect of deposited sediment on sediment characteristics. Site and treatment were fixed factors, time was a random factor and a site*treatment interaction was included. Where a significant site*treatment interaction (p<0.15) is reported, p-values for the effect of treatment at each site are given.
(continued on next page) Results of generalized linear modelling on the effect of deposited sediment on sediment characteristics. Site and treatment were fixed factors, time was a random factor and a site*treatment interaction was included. Where a significant site*treatment interaction (p<0.15) is reported, p-values for the effect of treatment at each site are given.
Appendix B (continued)
Appendix B (continued)
Results of generalized linear modelling on the effect of deposited sediment on the abundances of selected taxa and univariate indicators of community structure. Where a significant site*treatment interaction (p<0.15) is reported, p-values for the effect of treatment at each site are given. A Poisson distribution with a log link was used for the taxa and a normal distribution with an identity link was used for the univariate indicators.
Results of generalized linear modelling on the effect of deposited sediment on the abundances of selected taxa and univariate indicators of community structure. Where a significant site*treatment interaction (p<0.15) is reported, p-values for the effect of treatment at each site are given. A Poisson distribution with a log link was used for the taxa and a normal distribution with an identity link was used for the univariate indicators.
(continued on next page) Appendix C (continued)
(continued on next page) Appendix C (continued)
Appendix C (continued)
Appendix C (continued)
Results of multiple generalized linear modelling of sediment characteristics using hydrodynamic data. Binomial error distributions were used for the percentage data and a Poisson error was used for the number of burrows. For these variables, deviance rather than sum of squares are given.
Results of multiple generalized linear modelling of sediment characteristics using hydrodynamic data. Binomial error distributions were used for the percentage data and a Poisson error was used for the number of burrows. For these variables, deviance rather than sum of squares are given.
Appendix D (continued)
Appendix D (continued)
Results of multiple generalized linear modelling of biological data by sediment characteristics and hydrodynamic data. Poisson distributions were used for the number of burrows. For these variables, deviance rather than sum of squares are given. Where a species name appears as an independent variable, the densities used were from the surrounding sediment.
Results of multiple generalized linear modelling of biological data by sediment characteristics and hydrodynamic data. Poisson distributions were used for the number of burrows. For these variables, deviance rather than sum of squares are given. Where a species name appears as an independent variable, the densities used were from the surrounding sediment.
Appendix E (continued)
Appendix E (continued)
Appendix E (continued)
Appendix E (continued)
Related topics:
Wind WavesBenthic Invertebrate EcologyWave ExposureWind Wave
580 California St., Suite 400
San Francisco, CA, 94104
© 2025 Academia. All rights reserved