Thoughts, ideas, stories, presses, prezzies . . .

With this post I want to start sharing my grand grant ideas that I believe can develop into very exciting research projects provided sufficient interest from funding bodies. I follow the suite of brave Dr Manu Saunders who lists her rejected grants here.

The idea of studying bet-hedging strategies, as shared below, grew out of my work with Farrer Lab in New Orleans (USA) and was presented to American Australian Association. Few weeks ago I got this thrilling email:

“…
Dear Pawel,
Thank you for taking the time to submit your Australia to USA Scholarship application.
Following detailed review by our external panel, we regret to inform you that your application has not been selected for the next round. The decision of our panel is final and we cannot provide individual feedback due to the volume of applications received.
If eligible, we encourage you to apply next year.
Thank you,
Director of Finance, Education and Technology
American Australian Association
50 Broadway, Suite 2003, New York NY 10004
+1 (212) 338-6860 x 304
http://www.americanaustralian.org
….”

Executive Summary (100 words)

Wetland ecosystems minimize the risk of flooding, but increasing sea level coupled with increasing stochasticity of flooding regimes raise the questions related to the resilience of wetland plant communities. What adaptations do wetland plants have for surviving increasingly irregular floods? How do plants spread their risk and bet-hedge against unpredictable flooding and salinity regimes? Do soil microbes facilitate bet-hedging capabilities in invasive Phragmites australis versus native Spartina alterniflora? The proposed research project will tackle these issues in a series of field- and greenhouse-based experiments and provides essential knowledge for effective management and restoration of coastal regions.

Bet-Hedging_AAS_Grant_IDEA_Salinity_Flooding_Sun

Essay: Statement of Purpose (Word count: 1200)

Coastal wetlands are currently experiencing threats from global environmental change and are listed as exceptionally vulnerable to degradation (Laurance et al. 2011). At the same time these wetlands provide critical services to humans such as buffering from storm surge, stabilizing shorelines, reducing wave energy and supporting fisheries (Erwin 2008). Plant communities are the key determinants of coastal wetland resilience and govern their capacity to mitigate these threats (Schile et al. 2014). However, knowledge of the mechanisms of how plants cope with the dynamic coastal conditions is largely missing (Lytle & Poff 2004). Here I propose to understand the bet-hedging strategies that plants use in ecosystems exposed to dramatic disturbance events to spread their risk of extinction. Bet-hedging strategies have been well-studied in arid ecosystems where plant species produce soil seed banks with different levels of dormancy and bet-hedge against stochastic rainfall events: if seeds have no dormancy and all seeds germinate one year, the plant is at risk of losing all their offspring in the case of a drought, but if some proportion of their seeds are dormant, propagules will remain after the drought to germinate in future wetter years. While the bet-hedging strategy is well described for arid ecosystems, little is known how wetland plants hedge their bets for survival following major disturbance (i.e. flooding or hurricanes). Propagules (rhizome or seeds) dispersed into hurricane-riven habitats have to accurately bet-hedge against their chance of establishment under new flooding event. Wetlands seedlings that emerge too soon under new flooding regime may have insufficient resources to establish, given the high flood level while seedlings emerging later or next season may find suitable conditions for growth (under relatively lower flood level).

Microbial communities can strongly influence germination and establishment rates, and pathogen and mutualistic taxa are ubiquitous in soil and on the surface and inside of seeds. Thus I also seek to extend the bet-hedging research and ask whether microbial communities alter the capacity of wetland plant species to bet-hedge. Plant species that are particularly susceptible to microbial pathogens, like some native plants, may benefit from conservative bet-hedging strategies so they do not have to confront pathogenic microbes; whereas invasive plants tolerant to pathogen release may benefit from all-in bet-hedging strategies.

In the low-cost, simple, field- and greenhouse-based experiments designed for this research project, I propose to fill this critical data gap. The following two experiments will help to resolve two important factors that control resilience to disturbance in wetlands plant communities:

Clonal bet-hedging will be investigated in two pivotal wetland plant species (native Spartina alterniflora and alien Phragmites australis) in response to extreme flooding and salinity regimes. Bet-hedging response will be measured in a greenhouse experiment by studying resprouting capacity (number of buds resprouting vs. dormant) of rhizomes planted in a factorial design manipulating salinity (low vs. high) and flooding (low vs. high flooding). The effect of microbial communities on resprouting capacity will be tested by adding a sterile soil/live soil treatment to the experiment.
Seed bet-hedging will be studied in soil seed banks collected in the field. Specifically, soil cores will be collected from the area of large-scale sediment diversion that aimed to redirect sediments from the leveed Mississippi river towards degraded wetlands. Seed bet-hedging response of the field soil seed bank will be measured by looking at the percent of seeds emerging under the first flood mimicking sediment diversion (low salinity and low flooding regime) in relation to percent of seeds germinating under second flood event simulating extreme salt water intrusion (high salinity and high flooding).

Accelerating sea level rise coupled with increasing variability of flooding regimes pose many questions related to resilience and capacity of wetland plant communities (Bhattarai & Cronin 2014; Jankowski et al. 2017): What adaptations do wetland organisms have for inhabiting dynamic wetland ecosystems and surviving increasingly irregular floods? How do native versus alien plant species bet-hedge against stochastic and potentially deadly flooding regimes?

Building on findings of Farrer lab that examined the role of biotic factors in invasion success of alien plant species (i.e., composition of root microbial endophytes) I propose to contribute to current knowledge on invasion processes by studying bet-hedging strategies in wetland plants. There is still remarkably little knowledge on bet-hedging strategies in wetlands ecosystems. The proposed novel approach of examining bet-hedging strategies in native versus alien wetland plants has not yet been tested for wetland plant species neither in Louisiana nor in the world. Since climate change is expected to lead to increasingly variable environments, such as extreme flooding events (Karl & Trenberth 2003), understanding bet-hedging characteristics is crucial in preventing future species extinction risk and to help stabilize wetland habitats. Knowledge of how wetlands plant bet-hedge against dynamic environmental conditions, such as flooding and pulses in salinity, will enhance our ability to design successful wetland restoration projects. For example, knowledge of bet-hedging strategies in wetlands plants will aid growth of native against alien species and assist in choosing the optimum timing and technique for planting activities given the ongoing impact of global change. Furthermore, understanding how microbes influence bet-hedging will inform managers as to selecting the most suitable location for planting activities. More, given strong evidence of microbes effect on bet-hedging and emerging strategies in wetland plants this experiment could open-up a new frontier for wetland restoration ecology science.

Travel to the USA will allow me to continue growing my expertise in plant ecology and restoration with world-class experts. Louisiana is the only U.S. state with a Coastal Master Plan, which lays out strategies to combat coastal land loss and climate change and a timeline for implementation of large-scale restoration efforts. Like Australia, Louisiana’s economy is highly dependent on the coast that supports important sectors such as fisheries and tourism. More, local residents value coastal resources not only for their ecosystem services and a popular residential area but also for their intrinsic values that build a state-wide identity. Tulane has a number of leading experts in coastal ecology including some who have worked in wetland diversion projects. Tulane is also home to the ByWater Institute, which is an interdisciplinary center focused on the ecology and sustainability in the Mississippi Delta region. Dr. Emily Farrer and I already have a working relationship and are looking for funds to continue our collaborations. With this proposal, I plan to build on an innovative research project undertaken in 2017 by the Farrer Lab on the role of microbes in invasion success of Phragmites australis that I was part of as a postdoctoral researcher. Dr. Farrer focuses on investigating how biotic factors, such as interactions with microbial endophytes, are driving wetland resilience and invasion in the face of climate change. The study of microbial endophytes is a relatively new discipline in ecology and is relevant to practically all ecological systems, as all plants harbor microbiomes in their tissues. In my current postdoc position, I am gaining cutting edge training in microbial ecology, and remaining in a lab with this unique focus for another year will contribute an interesting perspective to my training in restoration ecology. The lab’s focus on P. australis is also highly applicable to ecosystems on a global scale because P. australis is one of the most ubiquitous plant species on Earth, including Australia (Meyerson et al. 2016). Overall, the U.S, and specifically Tulane, is an ideal place to implement my proposed research on how eco-physiological responses in wetland plants contribute to invasion in the context of global change.

The research project comprises of three periods:
1. Intensive preparation work resulting from the experimental design: setting-up greenhouse experiment, acquiring fieldwork permits, sourcing fieldwork consumables (March–June 2019).
2. Intensive greenhouse (4 months monitoring of seedlings’ bet-hedging response, Tulane University facilities) combined with field soil samples collection (Mid-Barataria sedimentation diversion, Louisiana) that will be conducted in the period of active hurricane season to emulate conditions when the bet-hedging strategy is pivotal in wetland plant establishment (July–October 2019)
3. Intensive analysis of gathered data, incorporation of the findings into a bet-hedging model and written and oral communication of results (November 2019 – March 2020). In order to ensure that the findings from this AAA fellowship are widely dispersed to both academic audiences and land managers, generated knowledge will be written up as a scientific article and published in a peer reviewed journal and will also be shared with representatives of local government and community groups (e.g. the Orleans Audubon Society, The Nature Conservancy of Louisiana, the Woodland Conservancy and the Gulf Restoration Network).

With over 80% of Australian population inhabiting a 50km strip of the coast it is fundamentally critical to understand how to sustainably manage the coastal environment. Wetlands are the border (ecotone) ecosystems that separate terrestrial habitat from the oceans. Ecotone habitats not only form an important front-line that buffers human communities against sea level rise and extreme flooding events but also harbor a large portion of global biodiversity.
Understanding how to increase the resilience of coastal land by restoring the most adapted plants is crucial to protect the coastal town, for example, New Orleans. The proposed research to test novel ideas of bet-hedging in wetland plants in relation to flooding regime, salinity fluctuations and microbes will improve the vegetation models used globally but also will help to protect and restore coastal communities here in the USA as well as in Australia.

 

References:.

  • Bhattarai, G.P. & Cronin, J.T. (2014) Hurricane Activity and the Large-Scale Pattern of Spread of an Invasive Plant Species. PloS one, 9, e98478.
  • Erwin, K.L. (2008) Wetlands and global climate change: the role of wetland restoration in a changing world. Wetlands Ecology and Management, 17, 71.
  • Jankowski, K.L., Törnqvist, T.E. & Fernandes, A.M. (2017) Vulnerability of Louisiana’s coastal wetlands to present-day rates of relative sea-level rise. Nature Communications, 8, 14792.
  • Karl, T.R. & Trenberth, K.E. (2003) Modern global climate change. Science, 302, 1719-1723.
  • Laurance, W.F., Dell, B., Turton, S.M., Lawes, M.J., Hutley, L.B., McCallum, H., Dale, P., Bird, M., Hardy, G., Prideaux, G., Gawne, B., McMahon, C.R., Yu, R., Hero, J.-M., Schwarzkopf, L., Krockenberger, A., Douglas, M., Silvester, E., Mahony, M., Vella, K., Saikia, U., Wahren, C.-H., Xu, Z., Smith, B. & Cocklin, C. (2011) The 10 Australian ecosystems most vulnerable to tipping points. Biological Conservation, 144, 1472-1480.
  • Lytle, D.A. & Poff, N.L. (2004) Adaptation to natural flow regimes. Trends in Ecology & Evolution, 19, 94-100.
  • Meyerson, L.A., Cronin, J.T. & Pyšek, P. (2016) Phragmitesaustralis as a model organism for studying plant invasions. Biological Invasions, 18, 2421-2431.
    Schile, L.M., Callaway, J.C., Morris, J.T., Stralberg, D., Parker, V.T. & Kelly, M. (2014) Modeling Tidal Marsh Distribution with Sea-Level Rise: Evaluating the Role of Vegetation, Sediment, and Upland Habitat in Marsh Resiliency. PloS one, 9, e88760.

 

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