1-5 p.m. Wednesday, May 11, 2022 • Indiana Memorial Union
The IU Environmental Resilience Institute’s 2022 Research Symposium is scheduled 1-5 p.m. Wednesday, May 11 in the Tree Suites of the Indiana Memorial Union on the Bloomington campus.
With presentations by over 20 IU faculty and students, the event will showcase the work of IU’s environmental resilience community on topics ranging from the natural sciences, to human systems, to environmental policy, to education. A poster session will provide an additional opportunity for attendees to learn about student work.
Light refreshments will be served. Seating is limited and attendees are encouraged to register in advance.
More information about presenters and talks is available below.
All flash talks will take place in the Dogwood Room.
ERI works with faculty members who are interested in expanding the broader impact of research, implementing a resilience-related service program, or incorporating resilience into teaching,
Over half of Indiana’s land is in agriculture and three-quarters of our ag land is used to grow annual grains to feed livestock and poultry, such as soybeans and corn. These annual crops and their infrastructure benefit from high levels of public and private investment. Imagine what Indiana would look like if we were to invest similarly in tree crops. Food trees can grow well in Indiana, enrich the ecosystem, and produce nutritious staple foods. Globally, efforts to incorporate trees into “two-story” agriculture, or “agroforestry,” are ranked as a most effective intervention for climate mitigation and adaptation. Through tree crops, landowners can eventually earn more money than they do through annual row crops.
Presenter: Julia Valliant, Assistant Research Scientist, Ostrom Workshop
The relationship between civil rights advocates and proponents of environmentalism was tenuous throughout the origins of the modern American environmental movement, but the energy crisis of the 1970s brought the fragility of this alliance into national focus. The imperative of energy conservation—touted by President Jimmy Carter in 1977 as “the moral equivalent of war”—appeared to some civil rights advocates to be at odds with the movement’s calls for racial economic equity. By 1979, when the second oil shock of the decade hit, the N.A.A.C.P.’s approach to energy politics became national news, and created a rift with other prominent civil rights organizations, including the National Urban League. Energy consumption politics became the unexpected baseline for politicians and pundits to measure how liberals engaged with civil rights, and led to a series of tangential debates over the energy implications of other racial equity issues, including desegregation busing and job creation. This paper explores the public debate over deregulation and the N.A.A.C.P.’s energy policy statement of 1978 in order to expose the fault lines between environmental and racial equity campaigns, and clarify the varied tenors of discrimination African Americans experienced within the environmental movement, as well as their disproportionate energy insecurity over the course of the late twentieth century through our current moment.
Presenter: Elizabeth Grennan Browning, ERI Research Affilate
Increasing human impacts have dramatically changed ecosystems worldwide. Climate change, ocean acidification, deforestation, and species’ extinctions among others are impacting the way species interact and share the landscape. Without mitigation, we are driving natural ecosystems to an unprecedented state with an uncertain future. In recent years, special efforts have been dedicated to understanding the ecological consequences of human impacts. As a result of these efforts, new lines of research, including conservation paleobiology, have emerged. Conservation paleobiology studies historic and pre-historic records to understand abiotic processes and species interactions before major human expansions and seeks to apply these understandings in conservation practice. Unfortunately, progress made towards understanding the theoretical basis of conservation issues usually remains solely in academic spaces and seldom contributes to the advancement of conservation practice. Additionally, conservation practitioners usually work on tight deadlines and budgets that prevent them from thoroughly evaluating the body of conservation research before important decisions are made. Similarly, policy makers do not necessarily possess a team of scientists capable of evaluating multiple research disciplines and putting them into the required socio-economic context.
Presenter: Silvia Pineda Munoz, Postdoctoral Researcher, Earth and Atmospheric Sciences
1:30 p.m. Concurrent research talks
Concurrent research talks will be held in the Dogwood, Persimmon, and Sassafras rooms.
Impact of artificial light at night on seasonal reproductive and migratory phenologies in North American songbird populations
Growing cities are introducing artificial light at night (ALAN) source as an escalating form of environmental pollution in today’s modern world, affecting wildlife behavior and physiology primarily regulated by photoperiod. Artificial light at night (ALAN) is affecting the biomass across the taxa that uses light cue to synchronize daily and seasonal endogenous processes. ALAN imposes several known negative impacts on the neuroendocrine system, metabolism, and seasonal reproduction of species living in the wild. However, we know little about the impact of ALAN on populations of birds that either live year-round in the same location or move to different latitudes across seasons. To test how ALAN affects the timing of spring night time activity in migratory juncos and onset of reproduction in resident and migrant junco populations that winter in sympatry but breed at different latitudes. We assessed seasonal reproductive response and spring induced migratory activity from initiation to termination of the breeding cycle in male dark-eyed juncos that were exposed to low intensity (~2.5 ± 0.5 lux) ALAN or dark nights. All groups experienced similar conditions and gradually increasing day length to mimic natural day length changes (NDL), except low intensity artificial light at night (ALAN) or dark nights (DN). As expected based on earlier research, the migratory juncos exposed to ALAN exhibited earlier induction and termination of spring night time activity than the migratory birds experiencing DN. In addition, resident and migrant birds exposed to ALAN initiated gonadal recrudescence earlier and terminated reproduction sooner as compared to their conspecifics experiencing NDL. Importantly, the difference in the reproductive timing of sedentary and migratory populations was maintained even when exposed to ALAN. This variation in the seasonal reproductive timing may likely have a genetic basis or be the result of early developmental effects imposed due to different latitude of origin. This study reveals first that latitude-dependent variation in reproductive timing is maintained despite exposure to ALAN, and second that ALAN accelerated reproductive development across both migrants and residents. These results corroborate a relationship between latitude, population, and reproductive timing while also revealing ALAN’s impact on seasonal reproductive timing. Combining information on both laboratory and field manipulations of ALAN will develop a better understanding for ecological consequences of the increasing urban environment on population diversity.
Diel activity patterns of urban mosquito vector species: Implications for mosquito control strategies
South Florida and south Texas have been historically afflicted by dengue and West Nile virus outbreaks and were the most affected areas during the Zika virus outbreak in the United States. Controlling mosquitoes is the most effective way to prevent arbovirus transmission, and one of its most important elements is the extent to which mosquito populations are exposed to insecticides. Mathematical models have been widely used to study the population dynamics of mosquitoes as well as to test and validate the effectiveness of arbovirus outbreak responses and mosquito control strategies. However, no modeling studies have focused on the effectiveness of adulticide applications to control mosquitoes at different hours of the day. Therefore, our objective was to assess the diel activity of mosquitoes in Miami-Dade, Florida and Brownsville, Texas, and to evaluate the effectiveness of insecticide spraying at different times of the day to control mosquitoes. Collections were done once a month for 96 hours from May to November 2019. To assess variations in the diel activity patterns of mosquitoes we performed a PERMANOVA followed by the SIMPER method to assess which species has contributed the most to the observed differences. To assess hourly variations in the mosquito community composition, we used the Dominance index. We used a stochastic compartmental model to simulate the population dynamics of different mosquito species (at 25oC) to determine the effectiveness of insecticide applications. A total of 14,502 mosquitoes comprising 17 species were collected in Brownsville and 10,948 mosquitoes comprising 19 species were collected in Miami-Dade. Aedes aegypti was the most common mosquito species being collected at all 24 hours of the day in both cities but peaking in abundance in the morning and evening. Our results showed that the mosquito community composition and abundance varied significantly throughout the day. However, in Brownsville, epidemiologically important mosquito species did not contribute to the hourly variation in the mosquito community composition, whereas in Miami-Dade, Ae. aegypti, accounted for approximately 50% of the variation. Our modeling results indicate that the effectiveness of adulticide applications varied greatly according to the hour of the day with 9 PM being the most effective time of the day to control Aedes species in Miami-Dade and Brownsville. Our results indicate that the timing of insecticide spraying interventions should be carefully considered by local authorities based on the ecology of mosquito species in the focus area.
Presenter: Andre Wilke, Postdoctoral Researcher, Epidemiology and Biostatistics
Trees, wind and dirt
When trees fall on hillslopes, they often uproot a volume of soil that is attached to the roots. Because trees usually fall downslope, this uprooted soil also moves down the hillslope, contributes to erosion, and leaves characteristic pit and mound shapes on the surface. The occurrence of these events are often driven by strong wind and leave a topographic legacy that influences the hydrology, ecology, and soil formation processes of the landscape. Yet the frequency of wind throw events is poorly constrained. The land surface, however, is a record of past wind throw events. Here, we develop theory that explains the topographic roughness of forest floors that reflects a balance between wind throw frequency, which creates pit-mound topography, and the magnitude of creep-like processes that smooth it. We propose a mechanistic-probabilistic model that relates the distribution of extreme wind speeds in southern Indiana to the distribution of wind throw production rates. We apply the theory and model to Brown County and constrain the frequency of this vital forest process and how the frequency may change with climate.
Presenter: Brian Yanites, Associate Professor, Earth and Atmospheric Sciences
The 2020 Edenville and Sanford, Michigan Dam Failures: Quantifying Geomorphic Change due to Catastrophic Flooding
Water storage dams are common and yet pose substantial hazards should they fail. Such catastrophic dam failures are likely to become more common given a changing hydroclimate and aging dam infrastructure in the USA. However, virtually no data exist on river response to dam failure. While intentional dam-removal studies provide insight, the geomorphic effects of a catastrophic dam failure should be meaningfully different and are not well-known. The May 19, 2020 failure of the Edenville and Sanford dams near Midland, MI provide an opportunity to quantify the geomorphic impacts of such a failure. These failures resulted in an estimated >$200M in property damage and displacing 10,000 residents to shelters and hotels during the COVID-19 pandemic.
Presenter: Harrison Martin, Graduate Student, Earth and Atmospheric Sciences
Pluralistic Ignorance and The Climate of Silence
Public discussion with important social issues—such as climate change—is an essential component to developing and implementing effective solutions. However, most Americans rarely discuss climate change, even amongst those reporting concern about the topic. My presentation will explore a key barrier to climate discussions—our lack of awareness that most others are concerned about climate change and support action to address the issue (i.e., pluralistic ignorance). I will first present research showing how (mis)perceptions that others are not concerned about climate change can prevent those concerned about climate change from sharing their opinion and engaging others in conversation about the topic. Then, I will present new research examining how pervasive and widespread Americans' and Hoosiers' misperceptions of other people's opinions are.
Nathaniel Geiger, Assistant Professor, The Media School
India and US expert assessments of climate solutions and barriers
There are many aspects to society that must change to mitigate and adapt to avoid the worst consequences of climate change. We conducted 60 semi-structured interviews with Indian and U.S. experts on what they view as the most challenging barriers, crucial solutions, and opportunities for change to occur to address climate change. We present a preliminary analysis of our results to identify points of convergence and divergence across national contexts and types of expertise.
Alora Cain, Graduate Student, O'Neill School of Public and Environmental Affairs
Seed selection in response to climate change by farmers in Uganda, Kenya and Tanzania: The impacts of seed networks and information access
Eastern African economies are heavily dependent on agriculture, with at least two thirds of all food production in the region coming from smallholder farmers. Temperature change and precipitation pattern changes have already led to changes in the growing season in East Africa and are expected to continue to do so, making climate change adaptation among smallholders an essential component of ensuring food security and realizing broader economic development goals. Many farmers in Kenya, Tanzania and Uganda depend on crop genetic resources which are predominantly shared through informal seed-exchange networks – such networks may be playing an under-appreciated role in the climate adaptation of rural smallholders.
Wesley Zebrowski, Graduate Student, O'Neill School of Public and Environmental Affairs
2:30 p.m. Break: Snacks, posters, conversation
Light refreshments will be served in the Dogwood Room.
3:00 p.m. Keynote presentation and discussion
Tom Kenote, Director of the College of Menominee Nation’s Sustainable Development Institute and partner with ERI through the Midwest Climate Adaptation Science Center, will speak about the Menominee Theoretical Model of Sustainability. Ellen Ketterson, IU Professor of Biology, will lead discussion following the presentation.
Location: Dogwood Room
3:40 p.m. Concurrent research talks
Predation: Multispecies justice in the time of planetary crisis
This presentation will include a showing of the 7-min trailer of the full-length documentary film Predation, followed by q&a with the creators and co-directors of the film, Andrea Jain and Vinnie Manganello. The film calls for us to center questions about the current environmental crisis and to address the issues concerning multispecies justice that arise when we examine the human and non-human animal frontline communities—those who first bear the brunt—of climate change and the capitalist industries and policies most responsible for contributing to it. We seek to better understand the following: on the one hand, the broadly deprived status of non-human animals across many cultural and religious formations, which thereby uphold the social and economic relations of capitalism, including those embodied in industrialized animal agriculture and its environmental consequences; and, on the other hand, activist communities that enact radical forms of solidarity between multispecies communities in the ways they eat and farm, thereby challenging those same relations and industries. We argue for using distinctively multispecies terms in order to reconceptualize culture under late capitalism and, in turn, imagine practices, policies, and institutions adequate to the ethical demands of the present.
Andrea Jain, Professor, IUPUI Religious Studies
Does renewable energy renew the endeavor in energy efficiency?
Improvement in energy efficiency (EE) has slowed globally since 2015 and is now falling short of the 2.6% per year target recommended by the United Nations Sustainable Development Goals, despite an abundance of EE opportunities. Barriers to EE have existed long before the rise in renewable energy investment. However, increased renewables adoption may have unintended consequences for improving EE as adoption may raise or lower the barriers to EE.
In this paper, we examine whether and how renewable energy adoption can accelerate or decelerate EE improvement. On the one hand, renewables represent a competitor to EE for managerial attention and budget. On the other, the adoption of renewable energy may increase the overall awareness of energy usage and drive EE improvement. Using site-level data from an industrial conglomerate, we estimate the impact of changes in renewable energy usage and in the acquisition approach on the energy efficiency of 183 sites across the globe from 2015 to 2020. At an aggregate level, we find that using renewables to meet 10% more of a site's energy demand led to an additional 2.0% improvement in EE. However, there is significant heterogeneity in the effects depending on the acquisition approach. We find that while purchasing renewable energy credits or entering into power purchase agreements led to gains in EE, installing on-site renewable energy generators had no effect.
To understand these gains, we surveyed site managers regarding their attitudes and intentions. The results suggest that there was a greater focus on EE by both managers and workers after increasing their renewable energy usage. We also find quantitative evidence of managers submitting more budget requests for EE improvements in the twelve months following increases in renewables. For corporations looking to use more renewable energy, we offer evidence of additional returns in the form of energy savings but realizing them requires careful consideration of the acquisition approach of renewables.
Christopher Chen, Assistant Professor, Kelley School of Business
Energy insecurity and the COVID-19 pandemic
Energy insecurity—defined as the inability to secure one’s basic energy needs—is a condition that plagues millions of Americans each year. A particularly severe instance of energy insecurity is when a household is disconnected from its utility service provider, which affects its ability to keep perishable food, power electronic medical devices, or maintain adequate temperatures in their homes. Governments can protect vulnerable populations from utility disconnections through policies, such as shut-off moratoria or seasonal protections that limit disconnections during more extreme weather months. In this analysis, we take advantage of temporary disconnection moratoria that states implemented during the COVID-19 pandemic to assess the efficacy of state protections on rates of disconnection, the manner in which households allocate spending across other essential needs, and uptake of bill payment assistance. We find that such protections are statistically associated with fewer disconnections and reduce the pressure on households to forgo expenses on medical care and food. Households that benefit the most from disconnection protections include Black and Hispanic households, those with small children, and those at the lowest income level. We conclude with a discussion of the robustness of our results and policy implications for energy insecure populations.
Trevor Memmott, Graduate Student, O'Neill School of Public and Environmental Affairs
Turning a coal state to a green state: Identifying themes of support and opposition to decarbonize the energy system in the United States
Decarbonizing the energy system is necessary to address climate change, yet the transition to low-carbon energy resources has been slow, and climate change continues to be a politically polarizing issue in the United States. Past research has shown that people want a future energy mix that is decarbonized but disagree on the policies to get there (Miniard et al., 2020). How do residents of Indiana, a historically Republican state which primarily relies on fossil fuel resources, think about the current and future energy mix and energy policy at the state level? We surveyed and interviewed Indiana residents (N = 48) to identify the motivations and perceptions driving their preferences for energy resources and support or opposition to state and federal energy policies. We find that a majority of participants want a decarbonized state energy mix in 2050 that primarily relies on solar and wind and decreases the use of fossil fuels. Support for decarbonization is driven by themes of protecting the environment and public health, reducing pollution, improving the economy, using low cost and available resources, and holding polluters accountable. We find that climate change is not a strong motivating factor. In contrast, opposition to decarbonization is driven by economic and employment concerns, fear, lack of familiarity, doubting the feasibility of renewable sources, and concerns about fairness. Thus, participants have nuanced reasons driving their support or opposition to decarbonizing the Indiana energy system, which are dependent on the energy source and policy and are not tied to climate change.
Deidra Miniard, Graduate Student, O'Neill School of Public and Environmental Affairs
Next-generation resilience leaders: Training undergraduates in regional climate through hands-on regional climate modeling research
Regional Climate Models (RCMs) generate high-resolution climate projections used for climate change impacts assessments and adaptation efforts; they are a key tool in resilience planning. The task of running RCMs and interpreting their results has traditionally been undertaken in academic settings: generally by researchers or practitioners with advanced degrees and highly-specialized training. This is largely due to the complexity of these simulations, both in terms of the complexity of running them and in terms of the complexity of extracting relevant information from the high-dimensional datasets that they produce.
Since 2020, the Regional Climate Research Lab (led by PI O’Brien, with funding from the PfEC Grand Challenge) has successfully engaged 7 undergraduate students in short-term research experiences that have trained the students how to set up, run, and interpret results from the International Centre for Theoretical Physics regional climate model RegCM4. The students, who have ranged from 1st to 4th year students, all started the research process with no scientific computing experience, and within two months of part-time work were able navigate IU’s High Performance Computing systems (e.g., BigRed3), set up unique RCM simulations with RegCM4, and process and interpret the RCM output.
This talk (1) outlines the training process and challenges, (2) describes the research projects that the students worked on (including one project that is currently being written up—led by one of the undergraduates—for Geophysical Research Letters), and (3) outlines prospects for expanding this effort to jointly produce regional climate information for Indiana while also training a new generation of IU graduates who are fluent in the use and generation of such datasets.
Travis O'Brien, Assistant Professor, Earth and Atmospheric Science
Educating for Environmental Change
Since 2017, Educating for Environmental Change (EfEC) has provided professional development programs to help K-12 science educators effectively teach the science and policy of climate change. Utilizing hands-on activities co-designed by IU environmental scientists, EfEC helps elucidate and deepen educator understanding of key concepts related to climate change including its causes, impacts, and the steps we can take to mitigate its severity. EfEC is a collaboration between Indiana University faculty, local K-12 educators, and the WonderLab Museum of Science, Health, and Technology. In 2020, EFEC received Indiana’s top environmental award, the Governor’s Award for Environmental Excellence, for “extraordinary initiatives in protecting the environment.”
Adam Scribner, Director of STEM Education Initiatives, School of Education
Implementing climate engineering lessons in secondary education
What if you were tasked with developing a technology solution to slow global warming? This 5-lesson teaching module introduces students to climate engineering from a variety of perspectives, including from the viewpoint of a climate scientist, an engineer, a decision-maker, and a citizen of Earth. Throughout the module, students collaboratively work through activities that facilitate their progress towards designing their own climate engineering design, culminating with a presentation to local decision-makers, stakeholders, and scientists.
Paul Goddard, Postdoctoral Researcher, Earth and Atmospheric Sciences
Research, Education & Stewardship to Restore our Environment: Educating residents on invasive species
While considerable resources are devoted to managing invasive plants on public and protected lands, the threat of invasive plants is equally great on private lands. Yet landowners lack information and resources on invasive plant species and their control, and on the types of native plants that would thrive on their properties, particularly in the face of strong herbivore pressure from overabundant white-tailed deer. We are addressing this gap with RESTORE, a multi-partner, education and citizen science initiative that offered workshops and established a tool kit lending library, and is engaging Monroe County landowners as citizen scientists to investigate the ecological factors affecting successful control of woody invasive plant species and restoration of native plant understory in deciduous woodlands. This talk will share methods and some of our emerging results.
Heather Reynolds, Associate Professor, Biology
Periodical cicada impacts on soil N cycling in a hardwood forest
Periodical cicadas (Magicicada spp.) affect tree physiology, food abundance for insectivorous predators, and soil porosity, but their impacts on ecosystem nitrogen (N) cycling remain poorly understood. We took advantage the Brood X emergence in 2021 to ask the following: How do periodical cicadas affect microbial N cycling, to what extent do changes vary over space and across time, and what are potential consequences of such effects for N retention and loss in forests? To address our questions, we conducted an observational study and an experimental study in the mixed hardwood forests of south-central Indiana. In the observational study, we sampled soils adjacent to (and distant from) cicada emergence holes, and measured rates of N mineralization and nitrification. In the experimental study, we compared N mineralization, nitrification and N-acquisition enzyme activities in forest plots fertilized with cicada carcasses (200 per m2) relative to adjacent control plots.
In the observational study, we found no differences in N cycling between soils adjacent to cicada emergence holes vs. soils distant from emergence holes. These patterns were consistent across multiple periods of the growing season and were unaffected by the dominant tree species present. In contrast, we found evidence that experimental addition of carcasses increased N cycling rates by 20-60%, with the largest effects occurring in plots dominated by tree species that associate with ectomycorrhizal fungi. Given that ectomycorrhizal-associated trees are declining across most of the region, our results suggest cicada impacts on forest N cycling during the nest emergence of Brood X (in 2038) may be attenuated.
Rich Phillips, Professor, Biology
The forest, the cicadas, and the holey fluxes: Periodical cicada impacts on soil respiration depends on tree mycorrhizal type
The simultaneous emergence of billions of periodical cicadas can have profound impacts on plants and animals in the forests, but the degree to which the cicadas impact soil carbon dynamics are poorly understood. For instance, each individual cicada creates its own emergence hole which has the potential to increase soil aeration and water infiltration—both of which affect tree physiological and soil microbial activity along with CO2 fluxes. However, the directionality and magnitude of the response is challenging to predict, as macropore formation increases oxygenation of the soil promoting autotrophic and heterotrophic respiration whereas saturating soil creates anerobic microsites that limit CO2 exchange with the atmosphere. Here, we took advantage of the emergence of billions of cicadas from the 2021 Brood X in the US eastern forests to investigate 1) How do cicada emergence holes affect soil respiration (RS) and 2) to what extent do these effects vary among forest plots dominated by trees that associate with arbuscular mycorrhizal (AM) versus those that associate with ectomycorrhizal (EcM) fungi? Soil CO2 efflux was measured systematically at three sites in southern Indiana containing respiration collars with zero, one, or two cicada holes. Collars were installed along hillslope and AM-EcM gradients to address the variation of RS relative to forest composition and topography. Generally (across all collars), EcM sites had a 14% greater RS rate than AM dominated stands. RS in AM stands increased by 31% and 57% for collars containing one or two cicada holes, respectively, relative to areas without cicada emergence. EcM sites had a 2% and 25% increase with one and two cicada holes, respectively. In mid-summer (i.e., 6-7 weeks after cicada emergence), cicada holes began filling up with soil, resulting in a little difference in RS across the landscape. The short increase of RS consequence of the cicada emergence is estimated to have increased the annual CO2 efflux; however, the legacy effects of the 17-year event are likely to be short lived. These data provide novel insight into the coordination of carbon stocks, forest composition, and the potential consequences of shifts between AM and EcM dominated stands while illustrating the responses of RS to environmental perturbations following cicada emergence.
Daniel Beverly, Postdoctoral Researcher, Biology
Detecting woody versus non-woody vegetation types in Savanna ecosystem with airborne remote sensing data
Vegetation in semi-arid regions is often a spatially heterogeneous mix of bare soil, grasses and woody plants. Detecting the fractional cover of woody versus non-woody vegetation, separate from other cover types such as biological soil crusts, dry grasses, and bare ground, is crucial for understanding the spatial patterns and temporal changes in semi-arid vegetation. In this study, we tested different configurations of unsupervised spectral unmixing classification of hyperspectral to estimate fractional cover of tall woody plants, grasses and other low stature vegetation, and other cover types both with and without the inclusion of LiDAR-derived canopy height information. We used 1m resolution hyperspectral and LiDAR data collected by the NEON airborne observation platform at the Santa Rita Experimental Range in Arizona. We assessed the accuracy of the classified maps compared to a reference dataset derived via supervised classification of 0.1m aerial camera images using both a simple metric ( mean absolute difference) and a fuzzy error matrix method. Our results show that fusion of canopy height data with hyperspectral information can separately identify tall woody plants versus non-woody vegetation. However, dense woody plant fractional cover is likely underestimated because spectral unmixing also detects within canopy other elements such as barks, grasses, bare soil and shadows as different classes. The spectral unmixing analysis identified an additional class that could represent dry grasses or biological soil crusts. Accurate estimation of grasses is lower than the other classes using both accuracy assessment methods, likely because of the presence of both active and senesced vegetation. This automated classification method should be useful in estimating fractional cover in other semi-arid ecosystems where hyperspectral and LiDAR data are available.
Rubaya Pervin, Graduate Student, Geography
Tree carbon responses to dryness: Does biomass partitioning buffer plant productivity from low soil moisture supply and high atmospheric water demand?
Plants exhibit remarkable potential to acclimate to water limitation, thereby sustaining productivity and growth under environmental stress. Changes in biomass partitioning between leaves, stems, and roots can help maximize acquisition of limiting resources. For example, trees growing in dry soils tend to increase relative allocation to roots to facilitate greater access to soil moisture (θ). However, for many trees, future water stress is likely to be driven by atmospheric vapor pressure deficit (D), instead of θ stress, and we know much less about allocation responses to atmospheric drought. D is an important driver of photosynthesis and plant productivity because stomatal conductance decreases with increasing D. Determining the extent to which plant productivity is buffered by allocation responses to different dryness stressors is therefore imperative to assess the resilience of terrestrial ecosystems to shifting hydroclimate regimes. In this study, we grew L. tulipifera (isohydric) and Q. alba (anisohydric) seedlings in experimental D and θ treatments to investigate how biomass partitioning differs among specific drivers of water stress. We found that morphological responses (e.g., wood density, leaf mass, above:below ground biomass ratio) were not consistent among D and θ associated stress, but were generally consistent across isohydric strategy. These shifts in biomass allocation overcame moisture stress and buffered plant productivity in response to elevated D. However, morphological adaptation did not prevent declines in plant water potentials and conserve net primary productivity in response to reduced θ.
Michael Benson, Graduate Student, O'Neill School of Public and Environmental Affairs
5:00 p.m. Informal reception
Join us after the symposium for an informal reception upstairs at Lennie's, 514 E. Kirkwood.