2018

_MG_6438Rose Adelizzi

Rose’s 2018 REU project was, “Don’t Go Breaking My Crust: How does physical disturbance affect nitrogen and carbon content in biological soil crusts and dominant plants and impact fungal community composition and colonization?”

Biological soil crusts are comprised of cyanobacteria, lichens, mosses, fungi, and bacteria that are capable of fixing carbon and nitrogen. Biocrusts are susceptible to physical disturbances to the soil surface, which may indirectly impact plant and fungal communities that depend on biocrusts for nutrient supplies. This study examined how long-term physical disturbances (stomping) affected the natural abundance of key soil elements (15N and 13C) and their stoichiometric ratios in the leaves of the grasses Bouteloua eriopoda and Bouteloua gracilis, which dominate the grassland biomes of central New Mexico. We also examined responses of fungal abundance to disturbance treatments (fungal colonization and growth of culturable fungi). Physical disturbance to the soil surface decreased percentage of nitrogen and increased C:N ratio in B. eriopoda within physical disturbance treatments at the grassland site. The percentage of nitrogen of physically disturbed B. eriopoda was 17% lower relative to the control. The C:N ratio of B. eriopoda leaves in disturbed plots was 17% higher compared to our control. The disturbance treatment reduced colonization of B. eriopoda roots by aseptate fungi by 78% in the shrubland site. Culturable fungi from roots were similar between the control and disturbance treatments, though plants with lower percentage nitrogen and a higher C:N ratio in leaves were associated with different fungal operational taxonomic units (OTUs) than plants with higher nitrogen levels. In arid ecosystems that have minimal soil organic matter and nutrient inputs, biocrusts can be a critical source of carbon and nutrients for plants and fungi. Measuring how these nutrients fluxes and fungal abundance between biocrust and plants differ under disturbed conditions is crucial to predicting the ecological response of these systems as humans continue to alter the environment via soil disturbance.

joeyJoey Di Liberto

Joey and Maya’s 2018 REU project was, “Microhabitat characteristics do not influence rates of brood parasitism by Molothrus ater on the nests of Vireo vicinior on the Sevilleta National Wildlife Refuge.”

Brood parasitism is a major stressor to reproducing birds and often contributes to nest failure. The energy costs associated with either rearing a non-host offspring or choosing to build and lay in a new nest following nest abandonment can be highly detrimental to the fitness of host birds. The Gray Vireo (Vireo vicinior) is a small, migratory passerine that breeds in the southwest US and northwestern Mexico and is known to be parasitized by the Brown-headed Cowbird (Molothrus ater). The aim of our study was to quantify how microhabitat variables affect the rate of brood parasitism in a known breeding population of vireos on the Sevilleta National Wildlife Refuge in New Mexico from 2017 to 2018. Specifically, we examined how surrounding juniper density, nest tree density, nest height, tree height, and distance to nearest neighboring nests and parasitized nests influenced the rate of brood parasitism of Gray Vireo nests. By measuring these environmental variables among others at each vireo nest, we assessed the rate of brood parasitism in relation to surrounding environmental characteristics in order to determine what factors may influence the rate of brood parasitism on vireo nests. Surrounding juniper density, nest tree density, nest height, tree height, and nest tree diameter did not explain the variation around rates of brood parasitism on vireo nests. Additionally, nearest neighbor, and nearest parasitized neighbor distances between nests could not to explain the variation in these rates of brood parasitism. These results strongly suggest that microhabitat characteristics are not correlated to changes in Gray Vireo nest parasitism rates and that changes in these rates are more likely caused by other environmental or behavioral variables. As Gray Vireo nests have a high rate of failure due to parasitism (~25% nest success; ~30% parasitized), it is not only crucial to better understand how these environmental variables influence vireo susceptibility to brood parasites on the Sevilleta NWR, but to also expand the current body of knowledge surrounding this system.

andrewAndrew Hsiao

Andrew’s 2018 REU project was, “Impact of soil processes on plant community structure in Sevilleta NWR grassland biomes.”

Grassland biomes dominate large portions of land all across the Sevilleta National Wildlife Refuge and are an important part of the refuge flora and fauna. Additionally, the refuge itself is comprised of numerous different soil types that vary across the landscape, possibly influencing the plant communities of arid grasslands. Water-holding capacity of soil has been closely linked as a main driver of biological activity (desert vegetation) in arid to semi-arid environments. This desert vegetation is suggested to strongly influence soil properties and productivity, i.e. the decomposition of organic matter into soil nutrients as well as their distribution within biomes. With an increase of aridity in these ecosystems, the concentration of N and soil organic C declines as well as a decrease in plant cover, suggesting the impacts of C and N soil concentrations in arid environments leading to less overall net primary production (NPP).  Previous research has separately examined soil nutrients of arid lands and the ecosystem’s NPP, but no studies have investigated the relationships between these two factors within grassland biomes and between different soil types. This project explores these relationships by quantifying several metrics of soil dynamics of varying soil types and assessing their connection to the above ground plant composition in arid grasslands. Here we show the association that processes of different soil types have on grassland plant communities. All three soil metrics were positively correlated with each other, confirming the interconnectedness of these processes. Additionally, all soil metrics significantly varied across most grassland soil types suggesting varying levels of fertility. Despite this, no statistical difference in plant diversity across soil types was observed. However, our results suggest grassland plant diversity to be negatively influenced with total plant cover through dominance effects of black grama (Bouteloua eriopoda).  Investigating the relationships of soil dynamics to the plant communities they support in arid grasslands are important for understanding the complex processes that regulate this arid ecosystem.

gabbyGabriela Jackson

Gabby’s 2018 REU project was, “Take me Home, Desert Roads: Effects of Roads on Plant Communities and Soil Dynamics on the Sevilleta National Wildlife Refuge.”

The ecological effects of roads on plant and soil dynamics are highly variable. This study focuses on roads of differing road management levels as well as in differing habitats, on the Sevilleta National Wildlife Refuge in New Mexico. We tested for soil quality and plant species composition, at 10 sites on the refuge, extending 20 meters from the center of each road. We expected to find that, as distance from the road increases, plant species composition and soil quality similarly increase, reaching equilibrium  at around 20 meters from the center of the road. This phenomenon is most clearly seen on the highly managed roads, whereas on the roads with low-level management, the species composition is already fairly diverse within the first 5 meters from the center of the road. We found that total live plant cover and plant diversity increased with distance from the road for all road types and locations, while soil salinity decreased (leading to higher soil quality) along the same distance gradient. This study can greatly help future researchers, both on and off the Sevilleta Refuge, plan their projects at an appropriate distance from the road (at least10 meters from the center of the road), so as to avoid detrimental road effects. Additionally, the information that we expect to conclude in this study can help inform refuge managers in best practices for non-disruptive road management.

marloMarlo McCarter

Marlo’s 2018 REU project was, “Grasshopper Diet and Spatial Variation.”

Grasshopper play an important role in the ecosystem in cycling nutrients as primary consumers and as prey for other vertebrates and invertebrates. Understanding of their diet determines which nutrients they help move into higher taxonomic levels and what affects they may have on plant community composition. Most diet studies of grasshoppers have focused on major agricultural pest species. The constraints which determine the diet of Grasshopper species is important due to their differences in seasonal variation, location and how their populations may be affected by in ecosystems shaped by future climates. Diet breadth and it’s variation influence population distributions and dispersal. To see if how specialized the diet of grasshoppers determined how variable their populations are over space I determined the variability and diet of eight species. I determined the diets of grasshopper species by analyzing gut content and mandibular traits. I calculated coefficient of variance of long-term population counts as a measure of variance from transect to transect of three sites. An understanding of the grasshopper diets will help determine which species may have a positive or negative influence as plant communities change due to climate change.

sienaSiena McKim

Siena’s 2018 ART REU project was, “Human-insect Intervention.”

ARTIST STATEMENT:

It’s easy to be frustrated at insects when they are buzzing around your house looking for a snack, like a house fly, or chirping under your refrigerator until early in the morning, like a cricket. But these insects, all though seem very common when in your own house, make up A very small fraction of the insects diversity that is in our world or even in your own neighborhood. We’ve learned to be afraid of most insects: “wasp and bees will sting you!” “don’t touch cockroaches, they carry diseases.” While we have praised other insects unfairly like butterflies for being a symbol of beauty and a pioneer of pollination. But the truth is, all insects play their own important roles. Some benefit humans more than others: hoverflies, native bees, and wasp help pollinate plants and crops, beetles, flies, and ants help decompose organic matter and recycle nutrients in their ecosystem. The list goes on. Insects play important roles, and they themselves are amazing organisms with unique morphology and life cycles seen in no other animal taxa.

After arriving at the Sevilleta, I was pleasantly surprised to see so much life here, insect life. Everyday since arriving I have seen new insects I hadn’t seen previously, each with their own behaviors and goals. I then questioned humans relationship to insects, how most interactions between the two seem to be always negative. I found that it was because of of two main factors: 1. incorrect information about insects has passed from one person to another and has been ingrained into people’s minds. 2. most of the insects that people interact with personally on a daily basis, like house flies and spiders, seem to be invading people’s personal space. The combination of negative, incorrect information and little exposure to a broader range of insects, has created this chasm between human and insects.

I wanted to address this negative human-insect relationship in two ways. First through exhibiting what insects truly do in real life, rather than just in one’s house, through an illustrated book. It shows their ecological roles, how valuable they are to maintaining our environment, as well as crushes some of those negative misconceptions people have about certain groups of insects. This is the factual, logical side. The second way I addressed the relationship is with two giant sculptures, one of a parasitoid fly, the other of a long-horned bee. They are made with a metal frame and fabric exterior. These two were meant to facilitate a positive interaction between human and insects. The sculptures are soft and inviting to touch and explore, seeing all the details on the insect that would be overlooked while looking at the actual organisms. This is the emotional, gut reaction side.

The project overall, is a tool for people to see the world differently through the awareness of insects. It crushes stereotypes of insects and initiates humans to change their behaviors and perspective towards insects, understanding that they do a lot of good for us. When people take the time to observe the insects outside of their house, they begin a path of discovery of how the earth works outside of our sheltered, human lives. They see what the earth has to offer them and makes for a better quality of life. individuals also become informed and can continue to defy the negative stereotypes of insects.

willWilliam Mejia

Will’s 2018 REU project was, “My Wet Hot Sevilleta Summer: Aquatic Invertebrate Communities, their habitats and Food-Web Structure.”

Arid climate is characterized by hot temperatures and a lack of precipitation which makes it difficult for plant and animal life to flourish. The water sources in these barren regions, although small and extremely uncommon, are crucial for species survival. These water sources are also the habitat of many beautiful and interesting aquatic invertebrates, yet they are often overlooked by desert studies. This study aimed to survey and compare the levels of invertebrate biodiversity at 18 different springs and artificial drinkers around the Sevilleta National Wildlife Refuge located in the Chihuahuan desert in New Mexico, USA.

The results obtained demonstrate that the aquatic invertebrate communities in the springs are extremely similar to each other and so are the communities in the artificial drinkers. Water quality assessments for pH and carbon dioxide did not provide any insight into the differences in the aquatic invertebrate community. We observed that as the water hardness (dissolved calcium and magnesium) in the artificial drinkers increases, the community richness decreases. Additionally, the amount of Chlorophyll A seems to have the opposite effect and has a positive linear relationship with richness in the artificial drinkers but no significant relationship in the springs. The food web structures of the springs are identical, regardless of tadpole presence, indicating that they do not have a critical role in the trophic system. These results will hopefully ignite an interest in the organisms within these water sources and how they can potentially cause havoc to the entire ecological community.

libbyElizabeth O’Brien

Libby’s 2018 REU project was, “How do physical disturbances to the soil surface affect nitrogen and carbon in biological soil crusts, dominate plants, and impact fungal colonization and community composition?”

The fungal loop hypothesis suggests that soil fungi couple N-fixing biological soil crusts (biocrusts) with plants to increase productivity, since nitrogen is a limiting nutrient in drylands. At the Sevilleta LTER, cyanobacteria dominate the microorganisms of the crusts. We conducted soil disturbance experiments to understand the relationships between nutrient transfer in plants and biocrusts, which remains poorly understood. We focused on three relationships within a disturbed environment: the influence of disturbance on microbial abundance, nutrient concentrations in soil samples, and the interactive effect between microbes and nutrients. We hypothesized that disturbance (stomping) decreases the overall productivity of a semi-arid ecosystem. We leveraged an existing experiment that has been stomping biocrusts at 10 6m x 6m plots for 5y in the grassland and shrubland regions of the Sevilleta. We analyzed the natural abundance values for carbon and nitrogen using isotope analyses, assessed total microbial biomass with chloroform fumigation, fungal abundance with ergosterol content, and nitrogen cycling with NO3 and NH4 concentration assays. Soil disturbance by stomping produced varied responses in this semi-arid ecosystem. Ergosterol content tended to increase with depth across both sites but was not dependent on disturbance. Ammonium concentrations are higher closer to the soil surface but are not dependent on disturbance. This project is time limited, but we plan on continuing this research with a 15N tracer experiment to explore the fungal loop more closely, continue isotopic analyses from roots, leaves, biocrust, and post-monsoon leaves, and identify sub-cultured fungi with DNA sequencing. Ongoing land use change and anthropogenic disturbance of biocrusts threatens the productivity and longevity of arid environments. This study and existing literature advocates for protecting biocrusts and their associated fungal and plant networks.

orlandoOrlando Rios

Orlando’s 2018 REU project was, “Bioreactivity of dissolved organic matter in microbial communities from organic and inorganic xenobiotics along the Rio Grande River continuum.”

The heterogenous microbial communities in Middle Rio Grande Basin (MRGB) play a critical role in processing organic matter that comes as a result of anthropogenic and natural discharges. In arid-land ecosystems, climate patterns and disturbances alter the river’s nutrient cycling in a seasonal trend; and so, the bio-reactivity of organisms. Although is known that these organism’s populations thrive over severe drought episodes, the proportions of processing dissolved organic matter over the various changes of nutrients availability remain unknown. As the middle Rio Grande basing receives significant nutrients input from the agricultural fields, urban runoff and wastewater treatment plants, the water quality is threatened as the industrial ecological footprint seizes to increase. In this experiment we expect to obtain parameters that will allow us to define the current organic matter processing in the Rio Grande and develop predictions of how changes in the ecosystem will alter this water resource. We anticipate that our project will be a starting point for the understanding of the contemporaneous impacts in the bioreactivity of watersheds since we are considering urban, agricultural and phenological disturbances.

IMG_3925Sarah Rose

Sarah’s 2018 ART REU project was, “The Normalization of Simulated Nature” and “The Resilient Cholla.”

ARTIST STATEMENT:

The Normalization of Simulated Nature
Simulated nature can exist in the form of virtual reality, social media, animation, and even gaming. It is a rendered version of our natural world that holds both truths and falsities. In this work, I investigate the normalization of simulated nature as it exists in society, especially for younger generations. I began this project by creating renders of plants around the field station, using an animation software called Blender. Once simulated scenes were produced, I used a portable projector to project the simulated scene onto the natural landscape. I then photographed the entire set up with a digital camera. My photographs collapse the layers of simulation and natural landscape so that at times it becomes hard to tell what is real and what is rendered. This project exists at an early stage of a wider investigation. I leave the work with open questions: How can we better technology to aid conservation of the environment instead of distancing us further from it? How can we utilize the excess of empathy existing online in the forms of likes, shares, and donations and bring that back into our everyday exchanges with nature?
The Resilient Cholla
The tree cholla (Cylindropuntia imbricata) is both resilient and aggressive, able to combat harsh environmental conditions as well as human impact. It is not alone in its fight for survival; it has mutualist counterparts. The two ant species Crematogaster opuntiae and Liometopum apiculatum provide protection against insect herbivores, in exchange for nectar. Intrigued by this relationship, I sought to translate it into cyanotype prints. Cyanotype is a 19th century photographic medium that has historically sat at the intersection of art and science, from Anna Atkins to Lia Halloran. I made my prints utilizing ink illustrations, flowers from the Sevilleta NWF, and black cardstock cut outs. My prints illustrate the “key players” in the interaction, the effectiveness of the two ant species, the visitation throughout a day, characteristics of the cholla, and a contextualization of the environment where the cholla thrives. I make this work with the intention of magnifying an ecological relationship that could be easily overlooked, in the hopes of encouraging viewers to consider the complexity of the ecology surrounding them everyday.

laura2Laura Sadorf

Laura’s 2018 REU project was, “Responses of Bouteloua eriopoda and soil stability to precipitation extremes in Chihuahuan Desert Grassland.”

Climate change is expected to increase the frequency and duration of extreme dry and wet years. Water is the most limiting resource in the semi-arid Chihuahuan Desert and investigating how semi-arid plants respond to precipitation extremes is pertinent to understanding how desert ecosystems will be altered in the future. To study these responses, I experimentally applied an extreme precipitation treatment to a Bouteloua eriopoda dominated grassland during June and July 2018 in the Sevilleta National Wildlife Refuge before the monsoon season. Seven 1 m2 plots received 10 mm water twice per week and seven 1 m2 plots received no treatment. I measured soil moisture, soil stability, and phenology of B. eriopoda within all 14 plots. While two natural rain events increased B. eriopoda growth in all plots, growth was significantly increased in response to the extreme precipitation treatment. Yet, control plots responded more quickly to natural rain pulses than continuously watered plots. Soil stability was not correlated with total cover of B. eriopoda. Soil stability was also measured at two adjacent long-term precipitation manipulation experiments. In comparison with this experiment, soils were more stable at watered plots in the long-term monsoon rainfall addition experiment and control plots in a long-term drought experiment. My results indicate that extreme precipitation events are beneficial for B. eriopoda dominated grasslands, and B. eriopoda is especially responsive to rain pulses between dry periods. Soil stability analyses show that the length of an experiment is important for more accurate assessment of soil stability. Previous studies found that B. eriopoda is sensitive to drought and these findings suggest that further investigation is needed to determine the interaction between B. eriopoda and soil stability, which may provide insight for future success of this dominant desert grass.

jenJennifer Schlauch

Jen’s 2018 REU project was, “Bee community variation among ecosystem types and sampling date over the pre-monsoon season at the Sevilleta National Wildlife Refuge.”

Native bees are economically and ecologically significant pollinators. Climate change may bring about changes in their interactions with floral communities and potential shifts in their phenology which could have important consequences for wild and agricultural plants. However, studies of how climate change may influence bee communities across the globe are currently sparse or incomplete. Within the United States, native bee diversity is highest in the arid southwest. Predictions on how this diverse bee community will be affected by climate change will be aided by the Sevilleta long-term pollinator monitoring program. One main goal of this project was to contribute to that dataset by 1) observing bee communities at a fine scale during a season of higher stress and 2) assessing bee communities using an alternative collection method, and 3) creating native bee and pollen reference libraries for further study of pollinator communities in a refuge that hosts one of the longest on-going studies of bee populations.

Here, we studied how pollinator communities differed among ecosystem types and varied over the course of the growing season in the Northern Chihuahuan Desert during a year of relatively high drought. Triweekly 45-minute sweep surveys were conducted in three core habitats at the Sevilleta National Wildlife Refuge and Long-term Ecological Research Site in Socorro County, New Mexico, from June to July 2018. We netted and counted bee pollinators to determine their species richness and abundance and identified blooming flower species in each site in a given week. Pollen from the most abundant flowering plants was collected, stained, and mounted on microscope slides to create a reference collection.

We expected extremely low floral and pollinator diversity in the dry weeks prior to the initiation of the monsoon season. We also predicted high rates of pollinator turnover during the summer growing season, and increased species richness following the expansion of floral diversity and abundance after monsoon rains. This study contributes to a better understanding of pollinator dynamics that may help prevent catastrophic events such as localized or complete extinction in a less predictable climate.

mayaMaya Stahl

Maya and Joey’s 2018 REU project was, “Microhabitat characteristics do not influence rates of brood parasitism by Molothrus ater on the nests of Vireo vicinior on the Sevilleta National Wildlife Refuge.”

Brood parasitism is a major stressor to reproducing birds and often contributes to nest failure. The energy costs associated with either rearing a non-host offspring or choosing to build and lay in a new nest following nest abandonment can be highly detrimental to the fitness of host birds. The Gray Vireo (Vireo vicinior) is a small, migratory passerine that breeds in the southwest US and northwestern Mexico and is known to be parasitized by the Brown-headed Cowbird (Molothrus ater). The aim of our study was to quantify how microhabitat variables affect the rate of brood parasitism in a known breeding population of vireos on the Sevilleta National Wildlife Refuge in New Mexico from 2017 to 2018. Specifically, we examined how surrounding juniper density, nest tree density, nest height, tree height, and distance to nearest neighboring nests and parasitized nests influenced the rate of brood parasitism of Gray Vireo nests. By measuring these environmental variables among others at each vireo nest, we assessed the rate of brood parasitism in relation to surrounding environmental characteristics in order to determine what factors may influence the rate of brood parasitism on vireo nests. Surrounding juniper density, nest tree density, nest height, tree height, and nest tree diameter did not explain the variation around rates of brood parasitism on vireo nests. Additionally, nearest neighbor, and nearest parasitized neighbor distances between nests could not to explain the variation in these rates of brood parasitism. These results strongly suggest that microhabitat characteristics are not correlated to changes in Gray Vireo nest parasitism rates and that changes in these rates are more likely caused by other environmental or behavioral variables. As Gray Vireo nests have a high rate of failure due to parasitism (~25% nest success; ~30% parasitized), it is not only crucial to better understand how these environmental variables influence vireo susceptibility to brood parasites on the Sevilleta NWR, but to also expand the current body of knowledge surrounding this system.

MoMoriah Van Voorhis

Mo’s 2018 REU project was, ” Grain Properties and Selection of Pogonomyrmex rugosus Mounds.”

The populations of Pogonomyrmex rugosus within Sevilleta National Wildlife Refuge construct their mounds with various rock types depending on location and source materials. Each available rock type has a unique thermodynamic property due to mineral composition. Additionally, thermal properties of a rock may vary due to grain size. Smaller grains have larger relative surface area and therefore are more exposed to solar radiation. The purpose of this study is to determine whether Pogonomyrmex rugosus are constructing their mounds in a way that corresponds with the thermodynamic properties of the selected grains. With surface temperatures currently reaching over 65° C and projected to increase over the next 50 years, it is critical to understand how P. rugosus tolerate the extreme heat. This study concludes that there is no overarching correlation in thermal conductivity and distance away from the mound when looking at multiple ant mounds across the Sevilleta National Wildlife Refuge. These results imply that ants are incorporating thermal conductivity of the mound in a case by case pattern rather than an overall trend and inspires future studies on this topic. Understanding the grain selection of P. rugosus will broaden our knowledge on how the unique geology of Sevilleta National Wildlife Refuge affects the organisms and how these organisms have adapted to the intense environment.

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