FRSES 2020 Abstracts
Download a complete list of abstracts here: FRSES_Abstracts_2020
First Oral Session 9:00 am – 10:15 am
Second Oral Session 10:45 am – 12:00 pm
- Room 374: Landscape Ecology & Global Change
- Room 376: Plasticity & Adaptation
- Room 378: Soil & Nutrient Cycling
Poster Session Categories:
- Aquatic Ecosystems
- Disturbance and Restoration Ecology
- Molecular Population Genetics
- Wildlife Ecology
- Insect Ecology
- Terrestrial Ecosystems
- Ecological Tools
Presenters are listed in presentation order.
Session 1 – Room 374: Ecological Modeling & Geography
Integrating Nasa Earth Observations into Live Fuel Moisture Models to Improve Wildfire Timing and Severity Forecasting in The Eastern Great Basin
Lauren Lad, NASA DEVELOP
The eastern Great Basin (EGB) covers approximately 411,000 km2 within the states of Arizona, Colorado, Idaho, Utah, and Wyoming. Partners at the Bureau of Land Management (BLM), the Idaho Department of Fish and Game, the National Weather Service, and the Great Basin Coordination Center (GBCC) are particularly concerned with Live Fuel Moisture (LFM). Living vegetation that fuels wildfires, referred to as live fuel, requires greater energy input to combust when wet and less energy input to combust when dry, making LFM a vital measurement for predicting wildfire risk and severity. To increase spatial coverage for the EGB from the 155 in situ observation sites, the NASA DEVELOP team modeled LFM using satellite data from Aqua and Terra Moderate Resolution Imaging Spectroradiometer (MODIS) and Suomi National Polar-orbiting Partnership (NPP) Visible Infrared Imaging Radiometer Suite (VIIRS). The team incorporated remotely sensed data into machine learning modeling techniques, such as the Random Trees Classifier through ArcGIS Pro, to develop a predictive model of LFM. Model accuracy was evaluated by testing generated values against historical data obtained from partners at the BLM and the GBCC. The LFM model benefitted partners by improving the spatio-temporal resolution for wildfire forecasts.
Utilizing Remote Sensing to Evaluate Herbicide Treatment Efficacy on Invasive Cheatgrass In Medicine Bow National Forest, Wyoming
Chiara Phillips, NASA DEVELOP National Program
Cheatgrass (Bromus tectorum), an invasive plant species in the Western US, occurs in the grasslands throughout Medicine Bow National Forest (MBNF). Cheatgrass is known to rapidly colonize disturbed sites and dramatically alter historic fire regimes and nutrient/water dynamics as well as outcompete native plant species that are important forage for mule deer and elk. In 2012, the Squirrel Creek Fire burned approximately 10,587 acres of land within MBNF, exacerbating the spread of cheatgrass. In 2015, the Wyoming Ecological Forecasting DEVELOP team identified areas of high cheatgrass abundance within the fire boundary to guide US Forest Service (USFS) herbicide spraying efforts to reduce cheatgrass in 2016. To detect conditions in 2019, we incorporated Landsat 8 Operational Land Imager (OLI) and Sentinel-2 MultiSpectral Instrument (MSI) data in machine learning models to create a probabilistic occurrence map of cheatgrass. This map was the basis for an analysis of the effectiveness of aerial spraying methods and to inform USFS future land management decisions. In the output from our final Generalized Linear Model (GLM), we found that treated areas decreased in cheatgrass cover by 36% while untreated areas increased in cheatgrass cover by 6%, suggesting that herbicide treatment has been effective.
Wildfire as A Catalyst for Upward Range Expansion of Trembling Aspen (Populus Tremuloides) In the Southern Rocky Mountains
Katie Nigro, Colorado State University
Increased temperatures due to climate warming are expected to result in an upward shift in elevation of species ranges, as they track changes in climate. Significant lags in species migrations have been documented, however, and could be tied to inadequate dispersal or lack of appropriate sites for establishment. Disturbances, like wildfire, may facilitate a more rapid shift in species ranges by reducing canopy buffering and producing more sites where succession can occur in the current climate. We investigated whether the West Fork Fire complex of 2013 promoted range expansion of aspen at its upper limit in the San Juan Mountains, CO by conducting seedlings surveys in burned and unburned areas. Aspen seedling establishment occurred up to 100 meters upslope of previous adult aspen stands and only in burned areas. Most of the aspen seedlings were found in bare or burned soil with low litter depths, suggesting a preference for the reduced organic matter conditions that fires create. The preliminary findings of this survey indicate that upslope migration of aspen is occurring via seedling establishment after fire in the San Juan Mountains of southern Colorado.
Predicting Critically Endangered California Condor Range Expansion to Reduce Development Threats
Arianna Punzalan, Colorado State University
California condors (Gymnogyps californianus) are critically endangered with just over 300 individuals in the wild. Condors narrowly evaded extinction during the 1980s when the population reached a low of 22, causing biologists to bring all remaining wild individuals into zoos for captive breeding programs. By the mid-1990s, condors were being released back into the wild from several release sites in CA, naturally forming two flocks in central and southern CA. Thousands of square miles of currently unoccupied historic condor range separate the two flocks and interactions between the two have been rare. However, movements detected in 2015 and 2016 from central to southern CA throughout the historical condor range and beyond, highlighted a need to understand how condors will use the landscape as their range expands. Unfortunately, alternative energy development, in the form of wind turbines, may proceed within currently unoccupied habitat without considering risks to condors despite the substantial threat it poses to birds. I used condor location data to identify factors that influence home range size and predict range expansion in California. Areas of overlap between predicted condor range expansion and commercially valuable wind generation will inform energy developers of critical habitat to consider during compliance processes.
Less but Better: Interaction Between the Amount and Quality of Habitat Drives Mammalian Occupancy in The Brazilian Pantanal
André Regolin, Colorado State University
We evaluated how habitat occupancy by mammals is shaped by an interaction of habitat amount and quality in the Brazilian Pantanal. We predict that when the amount of habitat is limited an increase in habitat quality will improve frugivore occurrence. We also expect that the habitat quality contribution to species habitat occupancy will vary among species according to species sensibility to habitat loss. We combined mammal detection data obtained from camera traps with land use and land cover maps to estimate the amount of habitat and measured habitat quality using local environment variables and distance to waterbodies. We fit univariate, additive, and interactive occupancy models to evaluate the relative support of each model and estimate species-specific occupancy and detection probabilities associated with various habitat features. Our results indicate that high quality habitats can improve occupancy in landscapes with low habitat cover. Our results also demonstrate that habitat quality matters even in landscapes with high habitat cover. Additionally, our findings suggest species sensitivity to habitat amount can determine the importance of habitat quality on occupancy. Although conservation policies tend to focus mainly on habitat amount, landscape management must include strategies to preserve and improve habitat quality.
Session 1 – Room 376: Evolutionary Biology
Genetic Diversity Accelerates Population Adaptation to A Shortened Generation Time
Lily Durkee, Colorado State University
The ability of populations to adapt, persist, and thrive in changing environments may depend on the genetic diversity present in a given population. Climate change affects the length and timing of seasons, which can alter or limit the time available for populations to complete their life cycles and successfully reproduce. Here, we assess the ability of populations with different levels of genetic diversity to adapt to a shortened generation time using the red flour beetle, Tribolium castaneum, as a model system. We created higher diversity populations by outcrossing 2-4 of the low-diversity populations together. We then compared the fecundity of the low- vs. higher-diversity populations under a shortened generation time. Preliminary results indicate that higher-diversity populations produced at least double the offspring when compared with low-diversity populations after only a single generation. This indicates that outcrossing alone may be sufficient to accelerate adaptation to a shorter generation time. These results are particularly relevant to populations living at the edge of their ranges, which are more likely to experience shifts in seasonality, possess less genetic variation, and have a higher genetic load when compared with core populations. Our results suggest that rapid adaptation to changes in seasonality can be facilitated by gene flow from other populations, regardless of whether the migrants are adapted to the new environment, through the rapid alleviation of genetic load.
Adaptation to Daylength Across Latitude Enables Range Expansion of The Tamarisk Leaf Beetle
Eliza Clark, Colorado State University
For many species moving or expanding their range boundaries, adapting to novel environments is key for further expansion. For hibernating or diapausing species, adapting to environmental cues that indicate seasonal change is crucial. The tamarisk leaf beetle, biological control agent for the invasive weed tamarisk, has rapidly adapted to different daylengths across latitudes that signal to the beetle to prepare for winter. We define a new trait, days until diapause at one daylength, to study adaptation at an individual level. We measured the genetic variation in days until diapause in one population in both home and away environments and the responses of eight populations from varying latitudes to both northern and southern environments. We found that days until diapause was highly variable in its home environment, but not in a novel environment and that the diapause behaviors of beetles from across the range significantly differed in each environment. The variation in days until diapause indicates that adaptive evolution is possible, but only when populations are near their home environment. Despite this, populations have become locally adapted across the range. These results explain an important reason for the success of the beetle and will help predict the rate of its range expansion and control of the target weed.
Conservation Genomics of The American Redstart
Matthew DeSaix, Colorado State University
In the past several decades, North American breeding avifauna have declined by approximately 3 billion individuals. In order for these declining species to persist under ongoing environmental change, they must be able to shift their distribution and/or adapt to changing selection pressures. Long-distance migrants in particular are exposed to a wide range of selection pressures throughout their annual cycle. Here, we describe a conservation genomics study of the American Redstart (Setophaga ruticilla): a long-time model species for full annual cycle research of migratory songbirds. Our results reveal finer-resolution geographic genetic clustering than previously reported for American Redstarts. We also detail geographic and environmental variables shaping genetic variation on the breeding ground. We highlight the importance of building on these results and incorporating genomic data into a full annual cycle framework. Specifically, integrating research of migratory connectivity and local adaptation will allow us to tease apart the influence of spatio-temporally variable selection pressures on different avian populations. Ultimately, these conservation genomic models will help us predict how migratory species will respond to climate change and provide an understanding of underlying evolutionary processes.
Detection of Microgeographic Adaptive Divergence in Spite of Low Genetic Structure in An Island Endemic
Rebecca Cheek, Colorado State University
Theory shows that divergent selection may be undermined at small spatial scales by the homogenizing effects of gene flow. The advancement of genomic techniques has made it possible to discover levels of genetic variation between locally adapted populations that defy traditional assumptions of the spatial scale of adaptation, though few studies have demonstrated this link between genotypic and phenotypic divergence in wild populations. The Island Scrub-jay (Aphelocoma insularis), endemic to Santa Cruz Island, is one of North America’s most range restricted species, yet exhibits repeated patterns of differentiation in bill morphology that mimics patterns of adaptive variation between allopatric mainland populations of the same genus. Here, we used single nucleotide polymorphisms (SNPs) to determine if divergent selection has acted on traits that show patterns of adaptive divergence between habitat types and whether environmental variation contributes to genetic structure. We found: 1) genomic variation associated with habitat and candidate loci linked with bill morphology, 2) weak but significant neutral population structure, and 3) evidence of genetic structure related to climate. These results add to the growing body of literature elucidating the capacity for highly mobile wild populations to adapt despite gene flow.
Variation and The Origins of a Novel Sexual Signal
James Gallagher, University of Denver
The recent appearance and rapid spread of a new mating song (purring) in Hawaiian populations of the Pacific field cricket has revealed an enormous amount of variation in a historically strongly sexually selected trait. The new song type, discovered in 2017, has sound characteristics drastically different from the ancestral song and is produced by wing morphology intermediate to the ancestral and a previously discovered obligately silent morph. The purring song is attractive to female crickets and less detectable to a deadly acoustically orienting parasitoid fly than the ancestral song, suggesting a private mode of communication among crickets. We recorded and analyzed male songs from long-studied sites and have found extreme variation in song characteristics that is rapidly changing within and among populations. Our findings also suggest that an obligately silent population—used for 15 years as a textbook example of rapid sexual signal loss in response to predation—has become mostly purring within only a few generations. Lastly, we introduce yet another previously unreported distinct song type (rattling) that has become widespread within one of our surveyed populations. Our discovery illuminates the role of variation in the early stages of sexual signal evolution.
Session 1 – Room 378: Human Dimensions
Fishing for Answers: Understanding Obstacles to Sustained Local Coral Monitoring in Community Co-Managed MPAs In the Philippines.
Kathrin Hauptfeld, Colorado State University
Data is required to manage and respond to changes in marine systems. Unfortunately, capacity for monitoring is often lacking in regions where biodiversity is greatest. Local monitoring (i.e. citizen science) is increasingly hailed as the sustainable alternative, placing resource decisions more fully into the hands of the affected people, in turn empowering local communities to better manage their resources, particularly in the developing context, where financial and human resources are limited, and local populations are dependent upon dwindling resources.
However, in the Philippines, local coral monitoring has widely failed despite two decades of shared coastal resource management between local governments and fisher-folk. Autonomous monitoring fails to sustain following the withdrawal of the training organizations. In this talk I present results from interviews and focus group discussions with fishers, local government officials, and training organizations to shed light on the question ‘Why are local communities failing to adopt and sustain coral monitoring practices?’ Results highlight mis-alignments in resource priorities, perceptions of the value of data, and theories of change among the three groups of actors.
“These Days, They Come Daily”: Elder Knowledge of Elephant Conflict Around Kibale National Park, Uganda
Martha Bierut, Colorado State University
Human-elephant conflict (HEC) is when human settlements conflict with elephant populations; most often, elephants raid the croplands of community members, decimating local livelihoods. This study uniquely explores the issue of HEC in a montane rainforest system as defined and explained by local community members through semistructured interviews with 28 elders in the village of Kyanyawara, adjacent to Kibale National Park in western Uganda. The most common reasoning for why elephants began to crop raid is that there is food competition within the park (n = 17). Since elephants began crop raiding in Kyanyawara 20 years ago, the elephants have been crop raiding in larger numbers (n = 22), they have been coming in higher frequency (n = 12), and they do not have predictability or seasonality as they have in the past. Mitigation suggestions were to improve and/or extend existing elephant trenches along park borders (n = 19), to improve the response of Uganda Wildlife Authority (UWA) rangers (n = 9), to implement beehive fences (n = 8), and to install electric fences (n = 8). Many opportunities for future research arose from this study, and the authors suggest continuing assessment of community suggestions and needs, close partnership with UWA, and the application of mitigation strategies as suggested by community members.
Samburu Pastoralist’s Perceptions of Drought Impacts and Adaptations in A Changing Social-Ecological System
Tomas Pickering, Colorado State University
Drought is a concept that varies in meaning and significance depending on the social-ecological activities it disrupts. Climate change is a driver likely to increase the frequency and severity of meteorological droughts in many regions of the world. To better understand how climate change and social-ecological factors interact to produce droughts we need to monitor droughts from community-local perspectives. We conducted focus group discussions with Samburu pastoralist communities in northern Kenya to (1) learn about how they define drought, (2) create a timeline of droughts since the 1970s and gauge their impacts, (3) learn about drought causes, and (4) understand their perceptions of drought-related long-term environmental trends. We then compared community identified droughts to remotely sensed NDVI-anomalies, vegetation droughts. In addition, we found since a 1984 drought, the Samburu have adapted their livestock management, increased their formal education, and diversified livelihoods to successfully resist impacts of climate change and a degrading environment. Women’s increased labor roles in society have largely facilitated this adaptation process. This community-based drought information creates a baseline with which to learn about what makes these communities resilient to drought.
A Spatial Analysis of Public Ecosystem Service Perceptions in Colorado
James Chamberlain, Colorado State University
Increased frequency of severe wildfire has led to greater pressure being placed on Colorado watersheds to provide a multitude of ecosystem services (ES). However, the spatial perceptions of ES benefits of people living along the Colorado Front Range remains poorly understood. I conducted a public-participatory GIS (PPGIS) mapping survey of households within Colorado’s Big Thompson River Watershed (n=125). I assessed perceptions of 12 ES categories through both monetary valuation and mapping in order to understand relative value to beneficiaries of the watershed’s services. Spatial patterns were analyzed to identify clustering and hot and cold spots of ES value. I found the strongest ES perceptions to be recreation, water, biodiversity, and aesthetics. Global Moran’s I analyses for spatial autocorrelation indicate that overall, ES values are randomly distributed (I=0.01; p=0.23). However, relational ES values appear to be clustered (I=0.27; p=0.09). ES value hot spots are located primarily in upstream areas. Cold spots are found in downstream areas. This study builds on PPGIS methods in the region, and continued refinement of these methods will prove useful for watershed management groups. Relating ES value hot spots and fire risk data is the next step in understanding the connections between social ES perceptions and threats.
Prescribed Fire Implementation Through A Human Lens: The Role of Landowner Engagement in A Colorado Prescribed Fire Program
Katherine McGrath, Colorado State University
Despite recognition of the value of prescribed fire in scientific literature and policy, a number of factors impede its widespread implementation in the United States. Social acceptance of prescribed fire is a key factor, making consistent and effective outreach important in efforts to increase prescribed fire implementation. The Arapaho-Roosevelt National Forest has set a goal to increase the level of prescribed burning, on its land and at a larger landscape level when possible. As part of this effort, several partners are working to improve active stakeholder involvement and education about forest restoration planning and implementation, with special attention paid to those who may be directly impacted by future prescribed fires.
Our case study on the Canyon Lakes Ranger District of the Arapaho-Roosevelt National Forest analyzes: strategies the USFS and its partners have used to communicate to landowners and meet their goals; challenges and benefits experienced on both the giving and receiving ends of outreach; and how outreach has been perceived by its recipients. Preliminary findings suggest that landowners are most satisfied with accessible, personalized outreach and experiencing successful projects locally, while managers stressed the importance of collaboration in building capacity, trust, and achieving objectives.
Room 374: Landscape Ecology & Global Change
How Does Rainfall Event Size Affect Ecosystem Responses During Drought in The Shortgrass Steppe?
Olivia Hajek, Colorado State University
Global climatic models forecast increased periods of extreme dry and wet periods as well as more frequent individual extreme rain events (i.e. deluges). These hydrological shifts are particularly relevant for semi-arid grasslands because of their sensitivity to changes in precipitation. Thus, we designed an experiment at the Central Plains Experimental Region (CPER) to evaluate how deluges affect ecosystem processes, particularly carbon cycling. Using rainout shelters and a watering pump system, we simulated four different precipitation regimes: drought, drought with a single deluge (63mm), drought with several small rain events (total 63mm), and a control receiving average rainfall. We measured changes in soil moisture, soil respiration, net ecosystem exchange, phenology, and number of flowering stalks throughout the growing season, and then at the end of season, we harvested above-ground biomass. Despite noticeable differences immediately following the single deluge, the overall results suggest that neither a single deluge nor several smaller events rescues a droughted system to the productivity of a normal year. These results provide valuable insight into how grassland ecosystem services may change as the result of climate change altering the hydrological cycle.
Aridity Drives the Spatiotemporal Patterns of Masting Across the Latitudinal Distribution of a Dryland Conifer
Andreas Wion, Colorado State University
Masting is the synchronous and irregular production of seed crops. Increasing temperatures and shifting precipitation regimes may alter the frequency and magnitude of masting, especially in species that experience chronic resource stress. In this study, we assessed the patterns of masting across the latitudinal distribution of a widely distributed dryland conifer species, piñon pine. Populations from chronically hot and dry areas tended to have greater interannual variability in seed cone production and smaller crop sizes. Mast years generally followed years with low vapor pressure deficits and high precipitation during key periods of the reproductive process, but the strength of these relationships varied across the region. Spatially correlated patterns of vapor pressure deficit better predicted synchrony in seed cone production than geographic distance, and these patterns were conserved at distances up to 500 km. Projected increases in aridity are likely to decrease the frequency and magnitude of masting in these dry forests and woodlands. Declines in seed production may compound climatic limitations to recruitment and impede tree regeneration, with cascading effects for numerous wildlife species.
Riparian Insect Diversity Along A Gradient of Pfc Contamination
Mauricio Soriano, University of Colorado, Colorado Springs
Despite risks to human health, polyfluorinated chemicals (PFCs) are used in many industries and consumer products. In Colorado Springs, their use in firefighting foam resulted in Fountain Creek Watershed contamination. PFCs are subject to biomagnification within the food web. Plants being producers uptake PFCs via water-uptake mechanisms passing the toxicant up the trophic ladder. As toxicant concentration increases with trophic level, potential disturbances to the ecosystem increases. Using methods executed at three different scales, we assess PFCs impact on ecosystems mediated through the effects on plants. We have five main goals: 1) Study the impact of PFCs load on biophysical attributes at the landscape scale. 2) Determine how PFCs bioaccumulate and/or biomagnify through the riparian food web. 3)The concentrations of PFC from field-collected plants, insect herbivores, and spiders will be determined using analytical methods. 4) Field collection was coordinated using landscape mapping such that replicate, random samples of the plants and arthropods will occur in impacted and unimpacted riparian areas. 5) Laboratory experiments will determine the extent which the PFCs enter consumers via their diet versus other routes of exposure. Results show that key markers of insect biodiversity declined along the PFC impacted gradient.
Regional Scale Assessment of The Mutualism Disruption Hypothesis
Morgan Roche, University of Tennessee, Knoxville
Impacts of invasive species are notoriously difficult to predict because the impacts vary with climatic conditions, composition of the recipient community, and abundance of the invader. Garlic mustard (Alliaria petiolata) is an herbaceous plant that has invaded many of the forest understories of Eastern North America. This invader impacts recipient plant species by disrupting mycorrhizal mutualisms. Inhibition of mycorrhizae by garlic mustard causes physiological stress in native plants, which results in diminished vital rates and population growth rates, and altered community composition. There is strong support for this mechanistic process in mycorrhizal plant response, but we do not how mutualism disruption changes over space or at across a range of garlic mustard abundance. We assessed the effects of garlic mustard on plant communities across the state of Illinois at a range of garlic mustard abundance. We expected garlic mustard presence to have a stronger negative effect on mycorrhizal herbaceous plant cover in comparison with non-mycorrhizal herbs and that the negative effects would be greater as garlic mustard abundance increases. A stronger impact on mycorrhizal plants would provide support for mutualism disruption as the primary mechanism of garlic mustard’s invasive success.
The Effect of Group Size On Per Capita Consumption, Longevity and Thermoregulatory Performance in European Honeybees (Apis Mellifera)
Michael Matthews, Colorado State University
Habitat loss, pesticide use, and parasite infections lead to a 30% die-off of North American Honey bee colonies each year. A recent study found that colonies must meet a population size threshold to survive harsh winter conditions. The source of the increased survivability observed in larger colonies remains undetermined. Michener’s paradox is a highly studied pattern known to limit group size in social insects. The paradox describes a negative correlation between group size and per capita production (PCP). Despite the intrinsic decline in PCP, Honey bee colonies preparing for winter can grow up to 50,000 individuals strong. In the present study, I investigate the potential advantages of larger group sizes. I hypothesize that larger groups benefit from increased thermoregulatory performance and decreased per capita consumptions (PCC). To test this hypothesis, I maintained large, medium, and small groups of worker honey bees in incubators. I subjected treatment groups to 12 hours of hot (38° C) and cold (18° C) temperatures a day. I recorded PCC and mortality measurements daily. Temperature probes recorded cluster temperature every 10 seconds. Statistical analysis of data collected is ongoing. Initial results indicate that medium-sized groups have the highest survivability, suggesting there is an optimum thermoregulatory density
Session 2 – Room 376: Plasticity & Adaptation
Environment, Population and Gene by Environment Influence on Genome-Wide A-To-I RNA Editing
Miles Whedbee, Colorado State University
Adenosie to Inosine (A-to-I) RNA editing is a fundamental post-transcriptional modification in metazoans. An evolutionary role for RNA editing has been hypothesized; however, the specific mechanisms by which editing influences evolutionary trajectories and the degree of impact on evolution is largely unknown. To assess influences of rearing environment, genetics and gene by environment interactions on RNA editing, we used a breeding design that leverages the Trinidadian guppy system for assessing plasticity and repeated evolution of RNA editing. We raised fish from two pairs of high-predation and low-predation populations in common lab environments with or without exposure to chemical cues of predators. We computationally predicted RNA edit sites in brain transcriptomes. Genetic background and rearing experience both partially explain total RNA editing as well as which sites are edited. In addition to global differences in editing, gene-level analyses identified differentially edited sites, i.e. genes in which edit levels differed based on predator exposure, population of origin, or the interaction between population and predator exposure. These results provide both a global and initial gene-level analysis of population genetic variation and rearing environment on RNA editing.
Guppy Love: The Effect of Mating Experience on Courtship Behavior in Male Guppies
Nathan Phipps, Colorado State University
Animal mating behavior is influenced by both genetic background and lifetime experience. We sought to investigate how genetic adaptations to environmental stressors interact with events within an organism’s lifetime to alter behavior. Reproductively isolated populations of Trinidadian guppies (Poecilia reticulata) occur in environments with either high or low predation rates. Evolutionary history with predators influences many phenotypes, including male courtship strategy. We observed male guppies from high predation, low predation, and intercross populations in their first encounter with a female. After 24 hours, we repeated the mating encounter to observe differences in mating strategy. We recorded occurrences of a variety of courtship behaviors in these encounters to determine how the effect of sexual experience on courtship strategy is influenced by population predation history. Our results describe the extent to which guppies from different genetic lines alter courtship behaviors after experience.
Can Plasticity Help Guppies Rise to The Challenge of Sea Level Rise?
Alexander Mauro, Colorado State University
One of the predicted consequences of climate change is an increase in the salinity of estuaries due to sea level rise. To start to understand how fish will respond to this, we investigated how behavior and body condition change in a euryhaline fish, Poecilia reticulata, subjected to a salinity increase and change in competitor composition that mimicked conditions predicted under sea level rise. We found that there is a tradeoff between salinity tolerance and competitive ability that results in a decrease in body condition when P. reticulata is in these conditions. However, our experimental fish were raised in freshwater and it’s possible that fish raised in brackish water would respond differently because of the effects of developmental plasticity. Further, it’s likely that the individuals that will respond to sea level rise in nature will have developed in brackish water. Hence, we repeated our experiment with fish raised in brackish water. We found these fish did not improve performance in brackish water and decreased performance in freshwater when compared to freshwater developed fish. Overall, we found that in P. reticulata plasticity does not appear to promote persistence in brackish water and that a trade-off between salinity tolerance and competitive ability could constrain an adaptive response to increasing salinity.
Acclimation Capacity as A Buffer to Climate Change: Using A Cold-Adapted Frog System to Uncover Drivers and Assess Estimate Quantification
Amanda Cicchino, Colorado State University
In the face of rapid environmental change, phenotypic plasticity is often an individual’s first line of defense. Plastic responses are often fast, and thus can offer a short-term solution for organisms trying to cope with changing environments. Understanding how plasticity in physiological traits affected by temperature (i.e., acclimation) evolves can help us identify trends in coping ability, which can inform conservation action. In this study, we quantified acclimation capacity of a cold-adapted, stream frog (Ascaphus spp.) along elevation gradients. We also investigated drivers of this plasticity, such as stream temperature variability and the availability of thermal refugia. Further, we used this system as a case study to investigate the approaches used for acclimation capacity. We found that these frogs have low levels of acclimation capacity in their thermal tolerance and high amount of variation among populations, which was not explained by temporal nor spatial variability in temperature. We found that the approach used to estimate acclimation capacity affected inferred vulnerability. Generalizations of physiological plasticity across systems will need to consider a priori expectations of physiological responses to experimental protocol, as well as underlying thermal trends to fully understand population vulnerability.
Room 378: Soil & Nutrient Cycling
Using an Isotope Pool Dilution Approach to Quantify Gross N2O Production and Consumption in Soils: Organic C Addition Stimulates N2O Consumption
Emily Stuchiner, Colorado State University
Nitrous oxide (N2O) is a potent greenhouse gas with a warming potential ~300x CO2, but a poorly constrained global budget. N2O consumption, the microbial reduction of N2O to N2, remains one of most uncertain aspects of the global budget because it is difficult to measure. We sought to better understand what drives N2O consumption by measuring this process in eight soils from Colorado, New Mexico, and Minnesota. We hypothesized that the primary control on N2O consumption is electron donor supply. To address this hypothesis, we incubated soils amended with either aqueous organic carbon (OC) or DI water (control) to discern how excess reductants impact gross N2O uptake. All soils were also enriched with 99 atom percent excess 15N2O, held at 60% soil water saturation, and incubated for 48 hr. We then used 15N2O isotope pool dilution to disentangle gross N2O production and consumption in response to the amendments. Our study revealed that N2O consumption was stimulated in response to OC in several, but not all, soils. Soils with a marked increase in gross N2O consumption appeared to overcome a C-limitation threshold, resulting in a depletion of oxidant supply, growth in microbial biomass, and increased transcription of nosZ, the N2O-consuming gene. These results make strides towards better defining the drivers of N2O consumption.
Can Intensification and Diversification with Legumes Enhance SOM In Semi-Arid, Dryland Wheat Farms?
Laura van der Pol, Colorado State University
Loss of organic matter (OM) through cultivation and increased drought due to climate change threaten the viability of dryland agriculture which supplies the majority of global grain. One strategy adopted by wheat farmers to enhance SOM has been to replace summer fallow with a pulse crop. This form of intensification has the potential to reduce soil erosion, increase SOM, and enhance farm income. Incorporating a leguminous crop such as peas could offer additional benefit since legumes may promote more persistent (mineral-associated – MA) soil C while enhancing N availability to subsequent crops. We tested whether dryland crop intensification enhanced SOM retention by contrasting wheat-fallow rotations to wheat-corn-millet and wheat-corn-millet-pea rotations in fields that have practiced one of these rotations for at least 8 years (n=5/rotation). We compared the amount of SOM as plant-derived particulate organic matter and microbial/root-derived MA OM and water-stable aggregates from 0-10cm as well as total C and N to a depth of 1m. Preliminary results suggest that intensification did lead to greater soil structure as well as SOM, though the effect of the legume pulse crop is uncertain. Our results will help determine whether legumes could enhance C sequestration on a decadal timescale.
Adaptive Multi-Paddock Grazing Increases Soil Carbon Stocks and Soil Health
Samantha Mosier, Colorado State University
Continuous grazing has led to significant losses of carbon (C) in grassland soils. Yet previous research has shown that rotational grazing, specifically adaptive multi-paddock (AMP) grazing, can increase soil C stocks in these grassland systems. By promoting grazing management that improves soil C sequestration and soil health, grasslands have a large potential to help alleviate rising atmospheric CO2 as well as increase the sustainability of the soil. Our research analyzed soils from 10 grasslands in southeast United States representing either AMP or continuous grazing grassland management. We quantified soil C stocks as well as the distribution of C among soil organic matter (SOM) pools with varying mechanisms of formation and stabilization in soils. Additionally, we analyzed several other soil health indicators across each management type. Our findings show that the AMP farms had over 13% more soil C and 9% more soil nitrogen compared to the continuous grazing farms. There were significantly more persistent C on AMP farms compared to continuously grazed farms. Additionally, overall soil health was higher on the AMP grazing sites, indicated by several soil health metrics. These findings provide evidence that AMP grazing could be implemented as a potential way to sequester more C and mitigate rising atmospheric CO2 levels.
The Good, The Bad and The Algae: Nitrogen Dynamics in A Large Tropical Lake
Jemma Fadum, Colorado State University
Lake Yojoa is the largest freshwater lake in Honduras and the economic backbone of the surrounding region. In the last 40 years Lake Yojoa has experienced a deteriorating trophic state. We hypothesize that the observed eutrophication is due to increased nutrient loading from land use/land cover changes within the watershed, pelagic loading from aquaculture and climate change related alterations to the physicochemical structure of the water column. Using legacy data from before the introduction of aquaculture and contemporary data on nutrient concentrations and secchi depth, we have reasonable evidence to conclude that Lake Yojoa has increased in trophic state due to altered seasonality of reactive nitrogen delivery. While the dry season, when watershed inputs were minimal, used to serve as a ‘recovery period’, the delivery of reduced nitrogen to the oxic epilimnion during mixing now maintains an elevated trophic state. These results highlight the importance of understanding the interaction of nutrient loading and seasonal changes in lake stratification. Without a mechanistic understanding of nutrient cycling in tropical lakes, such as Lake Yojoa, it will be difficult to maintain watersheds capable of performing a full range of ecosystem services such as supporting multiple human uses and serving as a natural and economic resource.
Predictors of Plant Functional Traits in A Novel Ecosystem
Alexander Goetz, University of Denver
Understanding ecosystem changes due to removal of invasive species requires addressing not only taxonomic species composition but also ecosystem functioning via traits of individual plants. We explore how Tamarix spp. treatment impacts functioning of the surrounding plant community, specifically habitat for the endangered Southwestern willow flycatcher (Empidonax traillii extimus). Its habitat is associated with tree branching structures (a functional trait) and presence of water (an abiotic characteristic), not species composition; it is unknown whether restoration activities are producing such conditions. We ask: Which removal methods and site characteristics in formerly Tamarix dominated stands predict ecosystem function optimal for endangered bird habitat? I sampled specific leaf area (SLA) and branching structure at 34 sites in Grand County, UT. Soil samples were also collected at these sites. I found high variability in both SLA and branching structure between sites and reaches, with a significant effect of soil electrical conductivity on vertical biomass distribution. Ecological function of novel ecosystems is particularly important in the context of evaluating land management outcomes; we seek to improve our understanding of the functional trajectory of degraded environments after restoration activity has occurred.