Progress 06/01/04 to 09/30/09
Outputs
OUTPUTS: Our overall objective in this project is to examine how changes in the plant community in wetland ecosystems alter the methane (CH4) cycle--an intimately connected suite of processes that is strongly influenced by both plant and microbial communities. We put together a combination of experimental and observational studies to explicitly test our hypotheses. By controlling a number of key abiotic factors (e.g., water level, sediment properties), a mesocosm experiment examined the direct effects of plant community composition and diversity on function. In contrast, a whole-wetland scale allowed to account for differences in abiotic factors such as soil C content, inorganic N availability, soil and water temperature, or hydrology. As part of the whole-wetland scale study, four wetlands were sampled in 2006 in Central Ohio for methane fluxes and plant above- and belowground biomass. Eighty-five mesocosms were installed at Waterman Farm, on the Ohio State University main campus, in 2004-2005, and planted in 2006. The mesocosms have been maintained, including weeding for undesirable species and maintenance of the irrigation system and water level. These mesocosms were sampled in 2007 (twice), in 2008 (three times) and in 2009 (once). These sampling events include many analyses (i.e., leaf area index, plant biomass, canopy structure, CO2 and CH4 emission from the soil-plant system, porewater sampling CO2 and CH4, and CO2 and CH4 emission from the soil). We also were able to investigate N partitioning between the different functional groups and the effect of plant diversity on N partitioning using 15N injection. PARTICIPANTS: Dr. Virginie Bouchard, School of Environment and Natural Resources, Ohio State University. PI on the project. Overview the successful completion of this project - schedule regularly meeting with co-PI, students, and collaborators to discuss sampling protocols, sampling schedules, and results. Dr. Craig Davis, School of Environment and Natural Resources, Ohio State University. co-PI on the project. Provided advices on plant diversity and plant population dynamics. Janice Gilbert and Rachel Schultz, School of Environment and Natural Resources, Ohio State University. PhD students on the project. Sharon Reed and Constance Rice, School of Environment and Natural Resources, Ohio State University, MS students on the project. Eric Saas and Amy Barrett, School of Environment and Natural Resources, Ohio State University, Research Associates. Erelyn Apolina, Gwen Dubelko, Tom Luff, Lars Meyer, and Mike Szutzer, School of Environment and Natural Resources, Ohio State University, Undergraduate students. TARGET AUDIENCES: Private environmental corporation involved in mitigation and creation of wetlands, state and federal agencies (such as Ohio EPA) involved in similar operation. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
In the whole-wetland scale study, we analyzed the effects of plant community composition by using the ordination axes' scores derived from non-metric dimensional scaling procedures (NMDS). Multivariate statistical techniques were utilized to parse out the effects of diversity and plant community from the potentially confounding environmental variables (i.e., water depth and soil factors). Diversity showed a negative relationship with aboveground biomass in both the clonal and nonclonal communities. However, plant community composition was a stronger predictor than diversity of the response variables. In fact, plant community was a stronger predictor for CH4 efflux in the nonclonal community than environmental factors such as soil organic matter content, pH and percent moisture. Thus, plant community composition is an important driver of ecosystem functioning in wetland ecosystems above and beyond the environmental factors that shape it. Our results indicate that experimental results of the biodiversity-ecosystem functioning relationship did not apply to the natural wetland ecosystems included in this study. Data analysis of the mesocosm data is still on-going. Preliminary results show no clear effect of plant diversity on gas emissions, while we observed a positive effect of plant diversity on some canopy metrics, leaf area index, and aboveground biomass data. The tussock functional group is more productive than the other functional group, and tends to enhance production when present in a mixture. We also observed a positive linear relationship between ecosystem respiration and LAI index. Statistical analysis will continue through the fall 2009 as the additional data are being analyzed. Overall, our data clearly indicate that controlled experiments (i.e., plots and mesocosms) should not be the only approach taken when investigating the biodiversity-function relationship. Large-scale field experiments need to become prevalent in this research theme. Additionally, your research, when completed, will provide fundamental data by which mitigation wetland practices might be improved. Many mitigation wetlands are currently designed with little diversity - or mitigation policy do not encourage any consideration toward plant diversity. If our data show some relationship between diversity and function, wetland mitigation policy will need to be revised by state agencies (Ohio EPA) and federal agencies (US EPA, US Army Corps of Engineers).
Publications
- Schultz, R., Bouchard, V., Frey, S. 2008. Carbon cycle dynamics: Do plant community composition and functional diversity make a difference in experimental wetlands. 8th INTECOL Wetland Meeting, Cuiaba Brazil, July 21-25. (Oral Presentation)
- Frey, S.D., Bouchard, V., Gilbert, J., Reed, S. 2004. Relating Plant and Microbial Community Composition and Diversity to Wetland Ecosystem Processes. Ecological Society of America, August 2004, Portland OR. Published on CD.
- Gilbert, J. 2004. Examining the link between macorphyte diversity, bacterial diversity, and denitrification function in wetlands. PhD Dissertation, Ohio State University
- Bouchard, V., Hossler, K. Schultz, R. 2008. Shoots, roots and microbes in wetlands: how they interact and why we care Invited Seminar in the Division of Global and Environmental Change seminar series, in the School of Earth Sciences, the Ohio State University. January 25, 2008. (Oral Presentation)
- Bouchard, V., Frey. S., Gilbert, J., Reed, S. 2007. Effects of macrophyte functional group richness on emergent freshwater wetland functions. Ecology, 88: 2903-2914.
- Bouchard, V., Frey, S., Gilbert, J., Reed, S. 2004. Relating plant and microbial community composition and diversity to wetland ecosystem processes. International Meeting in Ecology - Wetlands, Utrecht, The Netherlands, July 25-30, 2004, p. 40-41.
- Bouchard, V., Reed, S, Frey, S. 2004. Link between macrophyte diversity and carbon cycle in freshwater wetlands: effect of niche complementarity and sampling effect. International Meeting in Ecology - Wetlands, Utrecht, The Netherlands, July 25-30, 2004, p. 40.
- Rice, C., Bouchard, V., Frey, S., Schultz, R. 2008. Examining the effects of plant diversity and community composition on soil oxidation-reduction potential in wetlands. 8th INTECOL Wetland Meeting, Cuiaba Brazil, July 21-25. (Oral Presentation).
- Rice, C. 2009. Examining the effects of plant diversity and community composition on reducing conditions in the soil of experimental wetlands. MS Thesis, Ohio State University.
- Schultz, R., Bouchard, V., Frey, S. 2008. Do plant community composition and diversity really matter in a non-experimental setting 93rd ESA Annual Meeting, Milwaukee, Wisconsin, August 3-8 2008. (Oral Presentation)
- Schultz, R., Bouchard, V., Frey, S. 2009. Root production and methane dynamics: Impact of wetland functional group diversity and composition. 94th ESA Annual Meeting, Albuquerque, New Mexico, August 2-7 2009.
- Schultz, R., Andrews, A., OReilly, L., Bouchard, V., Frey, S. 2009. Plant community composition more predictive than diversity of carbon cycling in freshwater wetlands. Ecology, In review.
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Progress 01/01/08 to 12/31/08
Outputs
OUTPUTS: Our overall objective in this project is to examine how changes in the plant community in wetland ecosystems alter the methane (CH4) cycle--an intimately connected suite of processes that is strongly influenced by both plant and microbial communities. In many studies that have examined the diversity-function relationship, the plant community has been artificially assembled in small-scale plots. These controlled ecosystems allow the manipulation of an individual environmental parameter (i.e., plant community composition/diversity), while holding other variables constant. However, because of the artificial nature of these experiments, applying results from these simplified systems to large-scale ecosystems may be problematic. Indeed, in large-scale ecosystems, environmental factors strongly influence the structure of plant communities and also impact ecosystem processes such as CH4 cycling. Keeping these issues in mind, we had proposed a combination of experimental and observational studies to explicitly test our hypotheses. By controlling a number of key abiotic factors (e.g., water level, sediment properties), a mesocosm experiment will examine the direct effects of plant community composition and diversity on function. However, in natural ecosystems, plant communities respond to changes in environmental factors, and the response of function to diversity is the combined effect of diversity and abiotic factors. Thus, we also proposed to conduct an across-site field survey to address our hypotheses at the whole-wetland scale, accounting for differences in abiotic factors such as soil C content, inorganic N availability, soil and water temperature, or hydrology that are impossible to control at this level but that can be included as explanatory variables (in addition to diversity) in statistical analyses. We have continuously managed the mesocosms during 2008, including weeding for undesirable species and maintenance of the irrigation system and water level. Some individuals of plant were replaced in the early spring as a few died over winter. In 2008, the mesocosms were sampled in June, August-September, and November. These sampling events include most analyses (see below), with the exception of the redox electrodes. Indeed, platinum-tipped redox electrodes have been installed permanently in each mesocosm (see below) and are being monitored on a more regular basis. The field and lab methods used over the past year are described below. The routine analyses/sampling at the mescosms include: Leaf area index, plant biomass, canopy structure, CO2 and CH4 emission from the soil-plant system, porewater sampling CO2 and CH4, and CO2 and CH4 emission from the soil. We also were able to investigate N partitioning between the different functional groups and the effect of plant diversity on N partitioning using 15N injection. PARTICIPANTS: Dr. Virginie Bouchard, School of Environment and Natural Resources, Ohio State University. PI on the project. Overview the successful completion of this project - schedule regularly meeting with co-PI, students, and collaborators to discuss sampling protocols, sampling schedules, and results. Dr. Craig Davis, School of Environment and Natural Resources, Ohio State University. co-PI on the project. Provided advices on plant diversity and plant population dynamics. Rachel Schultz, School of Environment and Natural Resources, Ohio State University. PhD student on the project. Collected/overviewed the collection of the majority of the data at the mesocosm experiment. Will write her MS thesis on this topic and defend in late Fall 2009. Constance Rice, School of Environment and Natural Resources, Ohio State University. MS student on the project. Was in charge of building, setting up and sampling the redox probes in the mesocosms. Will write her MS thesis on this topic and defend in Spring 2009. Amy Barrett, School of Environment and Natural Resources, Ohio State University, Research Associate. Helped coordinate sampling and laboratory analyses. Erelyn Apolina, Gwen Dubelko, Tom Luff, Lars Meyer, and Mike Szutzer, School of Environment and Natural Resources, Ohio State University, Undergraduate students. Helped with sampling and laboratory analyses. TARGET AUDIENCES: Education activities: one PhD student, one MS student, and a number of undergraduate students (see personnel list for complete listing) have been involved in this project. In addition, one of Dr. Bouchard class (ENR 710 - Methods in Ecosystem Science) used the mesocosm experiment during the fall 2008 as their research project. They measured diverse ecosystem function such as soil respiration, litter decomposition, soil N cycling in the mesocosm. PROJECT MODIFICATIONS: As stated above, the lack of CH4 emission from the mesocosms forced us to re-direct our investigation to a broader study on the carbon cycle and to include other processes (such as redox measurements and iron analysis).
Impacts
Our initial analysis of the data collected in the across-site field survey shows that plant diversity was negatively related to above ground plant biomass, and had no effect on belowground biomass and gas fluxes. In contrast, plant communities (i.e., non-clonal vs. clonal vegetation; open to closed habitats) and water level seem to be important factors explaining the patterns observed among the measured ecosystem functions. We also observed a decrease of CH4 emission with greater root biomass, when the plots were saturated with water. These analyses will be completed in the winter 2008 and an article will be submitted for publication in early 2009. Surprisingly, the mesocosms are producing very little CH4 under field condition, leading us to re-direct our focus to other pathways of the C cycle and other redox processes. Data analysis has recently started on data collected at the mesocosms during 2008. Early results show no clear effect of plant diversity on gas emissions, while we observed a positive effect of plant diversity on some canopy metrics, leaf area index, and aboveground biomass data. The tussock functional group is more productive than the other functional group, and tends to enhance production when present in a mixture. We also observed a positive linear relationship between ecosystem respiration and LAI index. Statistical analysis will continue through the fall and winter 2008 as the additional data are being collected and analyzed. Our data clearly indicate that controlled experiments (i.e., plots and mesocosms) should not be the only approach taken when investigating the biodiversity-function relationship. Large-scale field experiments need to become prevalent in this research theme. Additionally, your research, when completed, will provide fundamental data by which mitigation wetland practices might be improved. Many mitigation wetlands are currently designed with little diversity - or mitigation policy do not encourage any consideration toward plant diversity. If our data show some relationship between diversity and function, wetland mitigation policy will need to be revised by state agencies (Ohio EPA) and federal agencies (US EPA, US Army Corps of Engineers).
Publications
- Schultz, R., Bouchard, V., Frey, S. 2008. Do plant community composition and diversity really matter in a non-experimental setting? 93rd ESA Annual Meeting, Milwaukee, Wisconsin, August 3-8 2008. (Oral Presentation)
- Bouchard, V., Hossler, K. Schultz, R. 2008. Shoots, roots and microbes in wetlands: how they interact and why we care? Invited Seminar in the Division of Global and Environmental Change seminar series, in the School of Earth Sciences, the Ohio State University. January 25, 2008. (Oral Presentation)
- Rice, C., Bouchard, V., Frey, S., Schultz, R. 2008. Examining the effects of plant diversity and community composition on soil oxidation-reduction potential in wetlands. 8th INTECOL Wetland Meeting, Cuiaba Brazil, July 21-25. (Oral Presentation)
- Schultz, R., Bouchard, V., Frey, S. 2008. Carbon cycle dynamics: Do plant community composition and functional diversity make a difference in experimental wetlands?. 8th INTECOL Wetland Meeting, Cuiaba Brazil, July 21-25. (Oral Presentation)
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Progress 01/01/07 to 12/31/07
Outputs
OUTPUTS: Activities include: 1. recruitment of a MS student (Constance Rice) in the fall 2008; 2. continuation the mentoring of Rachel Schultz, PhD student on the project; 3. sampling twice of the 80 mesocosms (installed at Waterman Farm, on OSU campus) in the summer 2007, in coordination with a team from the University of New Hampshire; 4 mentoring of four undergraduate students; analysis of the soil, plant and water samples in the Aquatic System Ecology Lab in Kottman Hall; and 5. analysis of the data. Events include: 1. two 10-day field day at Waterman Farm; 2. presentation of the results at three national/international (Ecological Society of America meeting, Society of Wetland Scientist meeting and International Soil Ecology Society meeting) and one local (Water Management Association of Ohio Annual Meeting) meeting; and 3. participation to local field/teaching day (e.g., Scarlet and Gray Ag Day at OSU, Farm Science Review) to discuss the importance of diversity. Services
include: 1. mentoring graduate and undergraduate students and lab manager.
PARTICIPANTS: At Ohio State University: Virginie Bouchard (Associate Professor), Rachel Schultz (PhD student), Constance Rice (MS student), Eric Saas (lab manager), Michel Gentile (undergraduate student), Amy Barrett (undergraduate student), Gwen Dubelko (undergraduate student) and Jenette Goodman (undergraduate student). At the University of New Hampshire: Serita Frey (Associate Professor), Lindsay O'Reilly (MS student) and Sarah Andrews (PhD student)
TARGET AUDIENCES: Target audience: scientific community, Ohio EPA, and private consulting involved in wetland mitigation.
Impacts
We are continuing collecting data to look at the relationship between plant diversity and ecological function in wetland ecosystems. Our initial data (published in Bouchard et al. 2007) demonstrated that an increase in plant diversity enhance below ground plant biomass and decrease methane emission to the atmosphere. This result is significant because it is the first research which actually demonstrate complementarity between wetland plant species below ground, and a potential link to less emission of a greenhouse gas (methane). Current research will demonstrate if this result stands in diverse situation of field condition and species assemblages.
Publications
- Bouchard, V., Frey. S., Gilbert, J., Reed, S. 2007. Effects of macrophyte functional group richness on emergent freshwater wetland functions. Ecology, 88: 2903-2914.
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Progress 01/01/06 to 12/31/06
Outputs
Motivated by the accelerated loss of species worldwide, understanding the link between biodiversity and ecosystem functioning has emerged as one of the central questions in ecology during the past decade. Because plant traits strongly influence ecosystem functions, the identity and diversity of plant species in a community are expected to impact the magnitude of ecological functions. This research is design to understand the ecological links between plant diversity and ecological function in wetlands.
Impacts
We expect to demonstrate that plant diversity is essential to maintain wetland function. Such demonstration will have potential application in the field of wetland restoration and creation. Many wetlands are being destroyed under the pressure of economical development, and they are mitigated. The mitigation wetlands often result in low diversity plant communities and poorly functional ecosystems.
Publications
- Bouchard, V., Frey. S., Gilbert, J., Reed, S. 2007. in review. Macrophyte diversity alters some critical wetland functions but not all. Ecology.
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Progress 01/01/05 to 12/31/05
Outputs
We did not collect any additional data in 2005, but spent the year analyzing three years of data. We anticipate submitting 2-3 articles in early 2006. We also received funding from the National Science Foundation to continue this research. We will start a 3-year study in 2006, with both field and mesocosm scale experiments.
Impacts
We expect to demonstrate that plant diversity is esseential to maintain wetland function. Such demonstration will have potential application in the field of wetland restoration and creation. Many wetlands are being destroyed under the pressure of economical development, and they are mitigated. The mitigation wetlands often result in low diversity plant communities and poorly functional ecosystems.
Publications
- Bouchard, V., Frey. S., Gilbert, J., Reed, S., in preparation. Macrophyte diversity alters some critical wetland functions but not all. Ecology. [expected to be submitted in January 2006].
- Reed, S., Bouchard, V., Frey, S. in preparation. Clonal dominant control plant- and microbial- function in wetland diversity experiment. Aquatic Ecology [expected to be submitted by April 2006].
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Progress 01/01/04 to 12/31/04
Outputs
Motivated by the accelerated loss of species worldwide, understanding the link between biodiversity and ecosystem functioning has emerged as one of the central questions in ecology. An overwhelming majority of the plant diversity-function investigations have been conducted in terrestrial ecosystems (mostly grasslands) and have focused primarily on plant productivity and nutrient uptake/retention, with a notable lack of information available on belowground processes (e.g., root dynamics, decomposition, trace gas fluxes). My lab has made an important contribution to this field by better understanding the effect of plant diversity on both aboveground and belowground processes in wetlands. In a 3-year experiment with 60 controlled mesocosms installed on The Ohio State University campus, we investigate the effect of plant diversity on plant productivity, bacterial diversity, and microbial-mediated functions related to C and N cycling, particularly denitrification and CH4
emissions. To my knowledge, none of the previous diversity-function studies have investigated this relationship to the extent that we have. Our innovative research demonstrated for the first time that, in wetland ecosystems, some functions (e.g., root production, methane emission) do respond to a change in diversity, while other functions (e.g., denitrification) are not linked to diversity.
Impacts
We expect to demonstrate that plant diversity is esseential to maintain wetland function. Such demonstration will have potential application in the field of wetland restoration and creation. Many wetlands are being destroyed under the pressure of economical development, and they are mitigated. The mitigation wetlands often result in low diversity plant communities and poorly functional ecosystems.
Publications
- Bouchard, V., Reed, S., Frey, S., Gilbert, J. 2005. Effect of macrophyte diversity and community composition on aboveground and belowground biomass allocation. Oecologia. In review.
- Frey, S.D., Bouchard, V., Gilbert, J., Reed, S. 2004. Relating Plant and Microbial Community Composition and Diversity to Wetland Ecosystem Processes. Ecological Society of America, August 2004, Portland OR. Published on CD.
- Bouchard, V., Frey, S., Gilbert, J., Reed, S. 2004. Relating plant and microbial community composition and diversity to wetland ecosystem processes. International Meeting in Ecology - Wetlands, Utrecht, The Netherlands, July 25-30, 2004, p. 40-41.
- Bouchard, V., Reed, S, Frey, S. 2004. Link between macrophyte diversity and carbon cycle in freshwater wetlands: effect of niche complementarity and sampling effect. International Meeting in Ecology - Wetlands, Utrecht, The Netherlands, July 25-30, 2004, p. 40.
- Gilbert, J. 2004. Examining the link between macorphyte diversity, bacterial diversity, and denitrification function in wetlands. PhD Dissertation, Ohio State University
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