Assemblage Structure, Production, and Food Web Dynamics
Transcript Of Assemblage Structure, Production, and Food Web Dynamics
Georgia Southern University
Digital [email protected] Southern
Electronic Theses and Dissertations
Graduate Studies, Jack N. Averitt College of
Spring 2016
Assemblage Structure, Production, and Food Web Dynamics of Macroinvertebrates in Tropical Island Headwater Streams
Keysa G. Rosas-Rodriguez
Follow this and additional works at: https://digitalcommons.georgiasouthern.edu/etd
Part of the Terrestrial and Aquatic Ecology Commons
Recommended Citation Rosas-Rodriguez, Keysa G., "Assemblage Structure, Production, and Food Web Dynamics of Macroinvertebrates in Tropical Island Headwater Streams" (2016). Electronic Theses and Dissertations. 1384. https://digitalcommons.georgiasouthern.edu/etd/1384
This thesis (open access) is brought to you for free and open access by the Graduate Studies, Jack N. Averitt College of at Digital [email protected] Southern. It has been accepted for inclusion in Electronic Theses and Dissertations by an authorized administrator of Digital [email protected] Southern. For more information, please contact [email protected]
ASSEMBLAGE STRUCTURE, PRODUCTION AND FOOD WEB DYNAMICS OF MACROINVERTEBRATES IN TROPICAL ISLAND HEADWATER STREAMS by KEYSA G. ROSAS-RODRIGUEZ
(Under the Direction of J. Checo Colón-Gaud)
ABSTRACT
Variation in long-term temperature and precipitation patterns will likely influence the decomposition and export of benthic organic matter and influence aquatic macroinvertebrate consumer communities. Tropical systems are relatively understudied; therefore basal information is urgently needed. As part of an ongoing long-term study, we monitored macroinvertebrates in two shrimp-dominated and fishless headwater streams within the Luquillo Experimental Forest in Puerto Rico from 2009-2010. We combined growth rates with yearly biomass data to calculate secondary production and examined gut contents to develop quantitative food webs. Macroinvertebrate assemblages were dominated by a few insect taxa, with similar biotic composition across streams and habitats, but different structure amongst habitats. Biomass and abundance were generally greater in pools, suggesting that pools may provide habitat stability and shelter. Alternatively, shrimp may provide secondary benefits by removing fine sediments given their high density in pools. Overall, aquatic insects had low biomass; therefore, their production was relatively low as is the case in most tropical areas. However, their turnover rates were not as high as expected. Secondary production appears to rely more on amorphous detritus and allochthonous organic matter rather than algal resources. These data are an important first step towards predicting the long-term effects that expected changes in rainfall and discharge will have in tropical stream communities.
INDEX WORDS: Food webs, Secondary production, Macroinvertebrates, Tropics, Headwater streams, Long-term dataset, Food content analysis
ii ASSEMBLAGE STRUCTURE, PRODUCTION AND FOOD WEB DYNAMICS OF
MACROINVERTEBRATES IN TROPICAL ISLAND HEADWATER STREAMS by
KEYSA G. ROSAS-RODRIGUEZ B.S. University of Puerto Rico at Mayaguez, 2004
A Thesis submitted to the Graduate Faculty of Georgia Southern University in Partial Fulfillment of the Requirements for the Degree MASTER OF SCIENCE STATESBORO, GEORGIA
iii
© 2016 KEYSA G. ROSAS-RODRIGUEZ
All Rights Reserved
1
ASSEMBLAGE STRUCTURE, PRODUCTION AND FOOD WEB DYNAMICS OF MACROINVERTEBRATES IN TROPICAL ISLAND HEADWATER STREAMS by KEYSA G. ROSAS-RODRIGUEZ
Major Professor: Committee:
J. Checo Colón-Gaud Tavis Anderson Lance Durden Alonso Ramírez
Electronic Version approved: May 2016
2
ACKNOWLEDGEMENTS
I would like to thank my two mentors and big brothers Checo Colón-Gaud and Alonso Ramírez for their unconditional friendship and guidance. The past and present members of their two labs have become my family and my life would not be the same without them. Stay DWTFS. I would also like to thank the members of my committee: Tavis Anderson, Lance Durden, and Doug Aubrey for their support. Thanks to Ray Chandler for always coming through with some statistical magic. This study would not have been able to be accomplished without the help of the dozens of undergraduate and graduate students and El Verde Field Station technicians that have been involved in the sample collection and processing during the last seven years. I would like to thank my family for not judging my life choices too harshly and continuing to support their grown up child’s quest to stay in school and put off that whole adult thing indefinitely. Lastly, I would like to thank Michael Vines and Rocket the cat for keeping me sane during the writing of this document. This material is based upon work supported in part by the National Science Foundation under Grant No. 0948507 and a Georgia Southern Professional Development Grant.
3
TABLE OF CONTENTS Page
ACKNOWLEDGEMENTS……………………………………………………………………….2
LIST OF TABLES ………………………………………………………………………………..4
LIST OF FIGURES …...………………………………………………………………………….5
LIST OF APPENDICES………………………...………………………………………………...6
CHAPTER 1. INTRODUCTION………………………………………………………….……...7
CHAPTER 2. COMPOSITION AND STRUCTURE OF MACROINVERTEBRATE ASSEMBLAGES IN TWO TROPICAL HEADWATER STREAMS, PUERTO RICO…….....11
ABSTRACT………………….…………………………………………….…………….11 INTRODUCTION……………………………………………………………………….11 METHODS……………...……………………………………………………………….14 RESULTS…………….………………………………………………………………….17 DISCUSSION…………...……………………………………………………………….19
CHAPTER 3. TROPHIC BASIS OF INSECT SECONDARY PRODUCTION IN TWO TROPICAL HEADWATER STREAMS, PUERTO RICO…………………………………….36
ABSTRACT……………………………………………………….……….…………….36 INTRODUCTION……………………………………………………………………….37 METHODS……………...……………………………………………………………….39 RESULTS…………….………………………………………………………………….44 DISCUSSION…………...……………………………………………………………….46
CONCLUSSIONS AND FUTURE DIRECTIONS.…………………………….………………56
REFERENCES………………….……………………………………………………………….59
4
LIST OF TABLES
Page Table 2.1. . Habitat quality parameters in Prieta and Gatos in riffle and pool habitats….….…...23 Table 2.2. Average monthly discharge and Richards-Baker Flashiness Index in Prieta……..….24 Table 2.3 Dominant taxa in Gatos and Prieta in terms of biomass and abundance…………...…25 Table 2.4. Diversity measures…………………………………………………………………...26 Table 2.5. Results of the PERMANOVA tests performed on a Bray-Curtis similarity matrix based on the average abundance and biomass of aquatic macroinvertebrate data of the two LEF streams…………………………………………………………………………………………...27 Table 2.6. One-way SIMPER analysis using habitat as the factor based on Bray-Curtis similarity (cut-off 50%)………………………………………………………………………………..……28 Table 3.1 Growth Rates for each size class of study taxa……………………………………..…50 Table 3.2. Estimates of mean annual abundance (inds./m2), biomass (mg/m2), production (mg m2 yr-1), and production to biomass ratios of the study species in the two sites…………………...51 Table 3.3 Annual secondary production attributed to food type (mg m-2 yr-1) in Gatos and Prieta……………………………………………………………………………………………..52 Table 3.4 Summary of select production studies from the published literature………………....53
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LIST OF FIGURES Page
Figure 1.1 The Luquillo Experimental Forest (LEF) in Northeastern Puerto Rico……………...15 Figure 2.1. Weekly discharge in Quebrada Prieta from February 2000 to December 2015.……29 Figure 2.2. Two-dimensional NMDS plots of insect assemblages……………………………....30 Fig 3.1 Percent foregut food content of each taxa…………………………………………….....54 Fig 3.2 Food resource consumption by macroinvertebrates in Gatos and Prieta in pool and riffle habitats…………………………………………………………………………………………...55
6
LIST OF APPENDICES Page
Appendix 2.1. Monthly average total assemblage abundance and biomass values ± SE……....31 Appendix 2.2 – Average yearly abundance and biomassof all taxa found in the two study streams……………………………………………………………………………………….…..32 Appendix 2.3. One-way SIMPER analysis using habitat as the factor based on Bray-Curtis similarity………………………………………………………………………………………...33
Digital [email protected] Southern
Electronic Theses and Dissertations
Graduate Studies, Jack N. Averitt College of
Spring 2016
Assemblage Structure, Production, and Food Web Dynamics of Macroinvertebrates in Tropical Island Headwater Streams
Keysa G. Rosas-Rodriguez
Follow this and additional works at: https://digitalcommons.georgiasouthern.edu/etd
Part of the Terrestrial and Aquatic Ecology Commons
Recommended Citation Rosas-Rodriguez, Keysa G., "Assemblage Structure, Production, and Food Web Dynamics of Macroinvertebrates in Tropical Island Headwater Streams" (2016). Electronic Theses and Dissertations. 1384. https://digitalcommons.georgiasouthern.edu/etd/1384
This thesis (open access) is brought to you for free and open access by the Graduate Studies, Jack N. Averitt College of at Digital [email protected] Southern. It has been accepted for inclusion in Electronic Theses and Dissertations by an authorized administrator of Digital [email protected] Southern. For more information, please contact [email protected]
ASSEMBLAGE STRUCTURE, PRODUCTION AND FOOD WEB DYNAMICS OF MACROINVERTEBRATES IN TROPICAL ISLAND HEADWATER STREAMS by KEYSA G. ROSAS-RODRIGUEZ
(Under the Direction of J. Checo Colón-Gaud)
ABSTRACT
Variation in long-term temperature and precipitation patterns will likely influence the decomposition and export of benthic organic matter and influence aquatic macroinvertebrate consumer communities. Tropical systems are relatively understudied; therefore basal information is urgently needed. As part of an ongoing long-term study, we monitored macroinvertebrates in two shrimp-dominated and fishless headwater streams within the Luquillo Experimental Forest in Puerto Rico from 2009-2010. We combined growth rates with yearly biomass data to calculate secondary production and examined gut contents to develop quantitative food webs. Macroinvertebrate assemblages were dominated by a few insect taxa, with similar biotic composition across streams and habitats, but different structure amongst habitats. Biomass and abundance were generally greater in pools, suggesting that pools may provide habitat stability and shelter. Alternatively, shrimp may provide secondary benefits by removing fine sediments given their high density in pools. Overall, aquatic insects had low biomass; therefore, their production was relatively low as is the case in most tropical areas. However, their turnover rates were not as high as expected. Secondary production appears to rely more on amorphous detritus and allochthonous organic matter rather than algal resources. These data are an important first step towards predicting the long-term effects that expected changes in rainfall and discharge will have in tropical stream communities.
INDEX WORDS: Food webs, Secondary production, Macroinvertebrates, Tropics, Headwater streams, Long-term dataset, Food content analysis
ii ASSEMBLAGE STRUCTURE, PRODUCTION AND FOOD WEB DYNAMICS OF
MACROINVERTEBRATES IN TROPICAL ISLAND HEADWATER STREAMS by
KEYSA G. ROSAS-RODRIGUEZ B.S. University of Puerto Rico at Mayaguez, 2004
A Thesis submitted to the Graduate Faculty of Georgia Southern University in Partial Fulfillment of the Requirements for the Degree MASTER OF SCIENCE STATESBORO, GEORGIA
iii
© 2016 KEYSA G. ROSAS-RODRIGUEZ
All Rights Reserved
1
ASSEMBLAGE STRUCTURE, PRODUCTION AND FOOD WEB DYNAMICS OF MACROINVERTEBRATES IN TROPICAL ISLAND HEADWATER STREAMS by KEYSA G. ROSAS-RODRIGUEZ
Major Professor: Committee:
J. Checo Colón-Gaud Tavis Anderson Lance Durden Alonso Ramírez
Electronic Version approved: May 2016
2
ACKNOWLEDGEMENTS
I would like to thank my two mentors and big brothers Checo Colón-Gaud and Alonso Ramírez for their unconditional friendship and guidance. The past and present members of their two labs have become my family and my life would not be the same without them. Stay DWTFS. I would also like to thank the members of my committee: Tavis Anderson, Lance Durden, and Doug Aubrey for their support. Thanks to Ray Chandler for always coming through with some statistical magic. This study would not have been able to be accomplished without the help of the dozens of undergraduate and graduate students and El Verde Field Station technicians that have been involved in the sample collection and processing during the last seven years. I would like to thank my family for not judging my life choices too harshly and continuing to support their grown up child’s quest to stay in school and put off that whole adult thing indefinitely. Lastly, I would like to thank Michael Vines and Rocket the cat for keeping me sane during the writing of this document. This material is based upon work supported in part by the National Science Foundation under Grant No. 0948507 and a Georgia Southern Professional Development Grant.
3
TABLE OF CONTENTS Page
ACKNOWLEDGEMENTS……………………………………………………………………….2
LIST OF TABLES ………………………………………………………………………………..4
LIST OF FIGURES …...………………………………………………………………………….5
LIST OF APPENDICES………………………...………………………………………………...6
CHAPTER 1. INTRODUCTION………………………………………………………….……...7
CHAPTER 2. COMPOSITION AND STRUCTURE OF MACROINVERTEBRATE ASSEMBLAGES IN TWO TROPICAL HEADWATER STREAMS, PUERTO RICO…….....11
ABSTRACT………………….…………………………………………….…………….11 INTRODUCTION……………………………………………………………………….11 METHODS……………...……………………………………………………………….14 RESULTS…………….………………………………………………………………….17 DISCUSSION…………...……………………………………………………………….19
CHAPTER 3. TROPHIC BASIS OF INSECT SECONDARY PRODUCTION IN TWO TROPICAL HEADWATER STREAMS, PUERTO RICO…………………………………….36
ABSTRACT……………………………………………………….……….…………….36 INTRODUCTION……………………………………………………………………….37 METHODS……………...……………………………………………………………….39 RESULTS…………….………………………………………………………………….44 DISCUSSION…………...……………………………………………………………….46
CONCLUSSIONS AND FUTURE DIRECTIONS.…………………………….………………56
REFERENCES………………….……………………………………………………………….59
4
LIST OF TABLES
Page Table 2.1. . Habitat quality parameters in Prieta and Gatos in riffle and pool habitats….….…...23 Table 2.2. Average monthly discharge and Richards-Baker Flashiness Index in Prieta……..….24 Table 2.3 Dominant taxa in Gatos and Prieta in terms of biomass and abundance…………...…25 Table 2.4. Diversity measures…………………………………………………………………...26 Table 2.5. Results of the PERMANOVA tests performed on a Bray-Curtis similarity matrix based on the average abundance and biomass of aquatic macroinvertebrate data of the two LEF streams…………………………………………………………………………………………...27 Table 2.6. One-way SIMPER analysis using habitat as the factor based on Bray-Curtis similarity (cut-off 50%)………………………………………………………………………………..……28 Table 3.1 Growth Rates for each size class of study taxa……………………………………..…50 Table 3.2. Estimates of mean annual abundance (inds./m2), biomass (mg/m2), production (mg m2 yr-1), and production to biomass ratios of the study species in the two sites…………………...51 Table 3.3 Annual secondary production attributed to food type (mg m-2 yr-1) in Gatos and Prieta……………………………………………………………………………………………..52 Table 3.4 Summary of select production studies from the published literature………………....53
5
LIST OF FIGURES Page
Figure 1.1 The Luquillo Experimental Forest (LEF) in Northeastern Puerto Rico……………...15 Figure 2.1. Weekly discharge in Quebrada Prieta from February 2000 to December 2015.……29 Figure 2.2. Two-dimensional NMDS plots of insect assemblages……………………………....30 Fig 3.1 Percent foregut food content of each taxa…………………………………………….....54 Fig 3.2 Food resource consumption by macroinvertebrates in Gatos and Prieta in pool and riffle habitats…………………………………………………………………………………………...55
6
LIST OF APPENDICES Page
Appendix 2.1. Monthly average total assemblage abundance and biomass values ± SE……....31 Appendix 2.2 – Average yearly abundance and biomassof all taxa found in the two study streams……………………………………………………………………………………….…..32 Appendix 2.3. One-way SIMPER analysis using habitat as the factor based on Bray-Curtis similarity………………………………………………………………………………………...33