in Virginia’s Eastern Shore mudflats · Diversity of benthic macroinvertebrates in habitats of...
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Diversity of benthic macroinvertebrates in habitats of Ulva lactuca and Gracilaria vermiculophylla in Virginia’s Eastern Shore mudflats Alissa Howard Mentored by Victoria Belfit Discussion The purpose of this study was to show the effects of G.vermiculophylla, a non-native red algae, on the benthic macroinvertebrate abundance and the diversity in Virginia’s Eastern Shore. It was determined that there was not a greater abundance and diversity of benthic macroinvertebrates in association with D.cuprea,Ulva lactuca and G.vermiculophylla. G.vermiculophylla did not reduce the abundance and diversity of the mudflat. The Shannon Diversity Index showed a small difference in H-values, but more data is needed to conclude a significant difference in diversity of benthic macroinvertebrates associated with G.vermiculophylla. From this study it can be determined that G.vermiculophylla has not altered the ecosystem in Burtons Bay Virginia. Time to preserve and sort organisms was a limiting factor in this research. Future research in this area would include increased sampling to determine if there is a significantly higher abundance and diversity of benthic macroinvertebrates in D.cuprea tubes associated with Ulva lactuca and G.vermiculophylla. It also would be beneficial to examine the diversity of G.vermiculophylla during each season and determine in which seasons the diversity of organisms is the highest. Introduction Gracilaria vermiculophylla, an estuarine algae, has been identified as a non-native species in the West Atlantic (Thomsen et al., 2006). Most non-native species like G.vermiculophylla are known for reducing population abundances and altering the community structure in ecosystems around the world (Sax and Gaines, 2008). Mudflats in Burton Bay Virginia, have been invaded by G.vermiculophylla ( see figure 1). This algae competes with the native algae Ulva lactuca and polychaete worm Diopatra cuprea. D. cuprea appears to provide an effective refuge for macrobenthic invertebrates from shorebird predation (Luckenbach, 1986). As a result Mangum et al. (1968) designated the species ‘ecosystem engineer’. The purpose of this study was to show the effects of G.vermiculophylla on the benthic macroinvertebrate abundance and diversity of a mudflat. It was hypothesized that there is greater macroinvertebrate diversity in D.cuprea tubes associated with Ulva lactuca than there is with G.vermiculophylla. Additionally it was hypothesized, that there is greater statistical significance in the diversity and abundance with D. cuprea and Ulva lactuca than D. cuprea and G.vermiculophylla. Results Graph 1: Shannon Diversity Index of all three habitats shows the diversity of H-values on a scale of 0-3. Three means most diverse and zero is least diverse. A Shannon Diversity Index is a mathematical measure of species diversity in a ecological community. Diversity indices provide more information about community composition than simply species richness. 0 0.5 1 1.5 2 2.5 3 Barren Diopatra w/ Ulva Diopatra w/ Gracilaria Index values Shannon Diversity Index 1 2 3 4 5 There was a greater benthic macroinvertebrate diversity in D.cuprea tubes associated with Ulva lactuca than there was with G.vermiculophylla, according to the Shannon Diversity Index. Average H-values in graph 1 are Barren; 1.05, D&U; 1.43 and D&G; 1.06. A One-Way ANOVA test of the null hypothesis, there is no difference in the diversity of benthic macroinvertebrates, resulted in a p-value of 0.71. Since this was greater than the 0.05 significance level, we failed to reject the null hypothesis. A One-Way ANOVA test of the null hypothesis, there is no difference in the abundance (total benthic macrobenthic invertebrates) of each habitat resulted in a p-value of 0.21. The null hypothesis was failed to be rejected at the 0.05 significance level. Therefore, there was not sufficient evidence to conclude that there was a significantly larger difference in benthic macroinvertebrate diversity, the abundance associated with D.cuprea tubes, and Ulva lactuca than there is with G.vermiculophylla. Results (cont’d) Acknowledgements Core sampling was used to collect benthic macroinvertebrates from three different habitats: (1) Barren (the control that contains no D.cuprea tubes or algae), (2) D.cuprea tubes with Ulva, and (3) D. cuprea tubes with G.vermiculophylla (see figure 1). A 10 cm by 15 cm PVC pipe with a stopper was used to collect the sediment and macroinvertebrates in each habitat. Core samples were sieved and macroinvertebrates were preserved in Formalin and stained in Rosebengal (figures 2 and 3) for further identification. A total of 260 macroinvertebrates were identified to species level. The total number of invertebrates from each habitat were counted and recorded. A Shannon diversity Index and a One-Way ANOVA determined whether or not the abundance (total macrobenthic invertebrates) and the biodiversity had a significant difference between the habitat types. Methods and Materials Luckenbach, M. (1986). Sediment stability around animal tubes: The roles of hydrodynamic processes and biotic activity. The American Society of Limnology and Oceanography, 31(4), 776. Mangum, C. P., Santos, S. L., & Rhodes, W. R. (1968). Distribution and feeding in the on uphid polychaete, Diopatra cuprea. Marine Biology, 2, 33–40. Thomsen, M. S., McGlathery, K. J., & Tyler, A. C. (2006). Macroalgal distribution pattern in a shallow, soft-bottom lagoon, with emphasis on the nonnative Gracilaria vermiculophylla. Estuaries Coasts, 29, 470-478. Sax, D. F., & Gaines, S. D. (2008). Species diversity and extinction: The future of native biodiversity. PNAS, 105, 11490–11497. doi: 10.1073/pnas.0802290105 References Figure 1 (left): Ulva lactuca green in color, shown on the mudflat and G.vermiculophylla intertwined. Sample #: Figure 2 (left): Ilyannassa trivittata the most common mud snail found on Eastern Shore mudflats. I would like to thank Mrs. Victoria Belfit and Dr. Mark Luckenbach, director of the Virginia Institute of Marine Science Eastern Shore Laboratory for all their time, hard work and funding of my project. I would also like to thank my wonderful faculty advisor, Mrs. Yvonne Gabriel for her constant guidance. Figure 3 (left): Samples were vigorously sorted at VIMS ESL using a dissecting microscope, forceps and scissors. Benthic macroinvertebrates were placed in vials, containing ethyl alcohol and the vials were organized based on sample number and phylum. Organisms were then identified down to species at school.
Transcript of in Virginia’s Eastern Shore mudflats · Diversity of benthic macroinvertebrates in habitats of...
Diversity of benthic macroinvertebrates in habitats of Ulva lactuca and Gracilaria vermiculophylla in Virginia’s Eastern Shore mudflats
Alissa Howard Mentored by Victoria Belfit
Discussion The purpose of this study was to show the effects of
G.vermiculophylla, a non-native red algae, on the benthic macroinvertebrate abundance and the diversity in Virginia’s Eastern Shore. It was determined that there was not a greater abundance and diversity of benthic macroinvertebrates in association with D.cuprea,Ulva lactuca and G.vermiculophylla. G.vermiculophylla did not reduce the abundance and diversity of the mudflat. The Shannon Diversity Index showed a small difference in H-values, but more data is needed to conclude a significant difference in diversity of benthic macroinvertebrates associated with G.vermiculophylla. From this study it can be determined that G.vermiculophylla has not altered the ecosystem in Burtons Bay Virginia. Time to preserve and sort organisms was a limiting factor in this research. Future research in this area would include increased sampling to determine if there is a significantly higher abundance and diversity of benthic macroinvertebrates in D.cuprea tubes associated with Ulva lactuca and G.vermiculophylla. It also would be beneficial to examine the diversity of G.vermiculophylla during each season and determine in which seasons the diversity of organisms is the highest.
Introduction Gracilaria vermiculophylla, an estuarine algae, has been identified
as a non-native species in the West Atlantic (Thomsen et al., 2006). Most non-native species like G.vermiculophylla are known for reducing population abundances and altering the community structure in ecosystems around the world (Sax and Gaines, 2008). Mudflats in Burton Bay Virginia, have been invaded by G.vermiculophylla ( see figure 1). This algae competes with the native algae Ulva lactuca and polychaete worm Diopatra cuprea. D. cuprea appears to provide an effective refuge for macrobenthic invertebrates from shorebird predation (Luckenbach, 1986). As a result Mangum et al. (1968) designated the species ‘ecosystem engineer’. The purpose of this study was to show the effects of G.vermiculophylla on the benthic macroinvertebrate abundance and diversity of a mudflat. It was hypothesized that there is greater macroinvertebrate diversity in D.cuprea tubes associated with Ulva lactuca than there is with G.vermiculophylla. Additionally it was hypothesized, that there is greater statistical significance in the diversity and abundance with D. cuprea and Ulva lactuca than D. cuprea and G.vermiculophylla.
Results
Graph 1: Shannon Diversity Index of all three habitats shows the diversity of H-values on a scale of 0-3. Three means most diverse and zero is least diverse. A Shannon Diversity Index is a mathematical measure of species diversity in a ecological community. Diversity indices provide more information about community composition than simply species richness.
0
0.5
1
1.5
2
2.5
3
Barren Diopatra w/Ulva
Diopatra w/Gracilaria
Inde
x va
lues
Shannon Diversity Index 1 2 3 4 5
There was a greater benthic macroinvertebrate diversity in D.cuprea tubes associated with Ulva lactuca than there was with G.vermiculophylla, according to the Shannon Diversity Index. Average H-values in graph 1 are Barren; 1.05, D&U; 1.43 and D&G; 1.06. A One-Way ANOVA test of the null hypothesis, there is no difference in the diversity of benthic macroinvertebrates, resulted in a p-value of 0.71. Since this was greater than the 0.05 significance level, we failed to reject the null hypothesis. A One-Way ANOVA test of the null hypothesis, there is no difference in the abundance (total benthic macrobenthic invertebrates) of each habitat resulted in a p-value of 0.21. The null hypothesis was failed to be rejected at the 0.05 significance level. Therefore, there was not sufficient evidence to conclude that there was a significantly larger difference in benthic macroinvertebrate diversity, the abundance associated with D.cuprea tubes, and Ulva lactuca than there is with G.vermiculophylla.
Results (cont’d) Acknowledgements
Core sampling was used to collect benthic macroinvertebrates from three different habitats: (1) Barren (the control that contains no D.cuprea tubes or algae), (2) D.cuprea tubes with Ulva, and (3) D. cuprea tubes with G.vermiculophylla (see figure 1). A 10 cm by 15 cm PVC pipe with a stopper was used to collect the sediment and macroinvertebrates in each habitat. Core samples were sieved and macroinvertebrates were preserved in Formalin and stained in Rosebengal (figures 2 and 3) for further identification. A total of 260 macroinvertebrates were identified to species level. The total number of invertebrates from each habitat were counted and recorded. A Shannon diversity Index and a One-Way ANOVA determined whether or not the abundance (total macrobenthic invertebrates) and the biodiversity had a significant difference between the habitat types.
Methods and Materials
Luckenbach, M. (1986). Sediment stability around animal tubes: The roles of hydrodynamic processes and biotic activity. The American Society of Limnology and Oceanography, 31(4), 776.
Mangum, C. P., Santos, S. L., & Rhodes, W. R. (1968). Distribution and feeding in the on uphid polychaete, Diopatra cuprea. Marine Biology, 2, 33–40.
Thomsen, M. S., McGlathery, K. J., & Tyler, A. C. (2006). Macroalgal distribution pattern in a shallow, soft-bottom lagoon, with emphasis on the nonnative Gracilaria vermiculophylla. Estuaries Coasts, 29, 470-478.
Sax, D. F., & Gaines, S. D. (2008). Species diversity and extinction: The future of native biodiversity. PNAS, 105, 11490–11497. doi: 10.1073/pnas.0802290105
References
Figure 1 (left): Ulva lactuca green in color, shown on the mudflat and G.vermiculophylla intertwined.
Sample #:
Figure 2 (left): Ilyannassa trivittata the most common mud snail found on Eastern Shore mudflats.
I would like to thank Mrs. Victoria Belfit and Dr. Mark Luckenbach, director of the Virginia Institute of Marine Science Eastern Shore Laboratory for all their time, hard work and funding of my project. I would also like to thank my wonderful faculty advisor, Mrs. Yvonne Gabriel for her constant guidance.
Figure 3 (left): Samples were vigorously sorted at VIMS ESL using a dissecting microscope, forceps and scissors. Benthic macroinvertebrates were placed in vials, containing ethyl alcohol and the vials were organized based on sample number and phylum. Organisms were then identified down to species at school.
