2023

Taeya Boi Doku

Drought Legacy & Cyanobacteria Recovery under Variable Watering

Biological Soil crusts are communities of cyanobacteria that live on the surface of bare arid soils. They can take decades to establish, stabilize the soil, and serve as nitrogen fixers. My summer project known as the Legacy Drought Recovery (LDR) project capitalizes on the existing infrastructure in the Sevilleta National Wildlife Refuge’s Black Grama Grasland to further investigate the recovery of cyanobacteria in these biological soil crusts three years after the conclusion of a manipulated extreme 7-year drought and delayed monsoon rainfall from 2013-2020. Despite existing in the same experimental site, the previously droughted, delayed monsoon and control soils have different cyanobacterial presences and levels of soil stability. The LDR tracked the rates of cyanobacterial recovery under simulated high and low precipitation patterns over a span of 5-weeks. Though the presence of regular precipitation events was expected to expedite the recovery of these cyanobacteria and soil stability levels; the lack of monsoonal rains during the experiment and 100+ degree highs made it so that the 20ml watering events (the standard amount qualifying a monsoonal precipitation event) were not enough to produce statistically significant results. The data collected showed preliminary trends wherein high-frequency waterings had a positive impact on the undisturbed (control) soils, delayed monsoon soils preferred low-frequency events and droughted soils showed little growth in stability or cyanobacterial presence under either. The legacy of drought and delayed monsoon rains continued to be present through the gradation of cyanobacterial community presence and soil stability.

Alex Cottrell

Impacts of Non-native Ungulates on Desert Springs

I am Alex Cottrell, and my research focused on assessing the distribution and prevalence of non-native ungulates near water sources at the Sevilleta National Wildlife Refuge. Globally, the presence of non-native ungulates has been linked to ecological degradation due to factors such as overgrazing and soil disruption caused by their hooves. Notably, the Sevilleta environment presents a distinct arid setting where feral horses and cattle have established viable populations. Given the ecological delicacy of this ecosystem, the project aims to elucidate the extent to which these species impact both biotic and abiotic elements, thereby contributing to effective refuge management strategies. These goals were accomplished by measuring the vegetation coverage, soil compaction, number of non-native ungulate tracks, and grazing disturbance along a 10-meter transect using a 1-meter quadrat in two directions of the water source. With this data, we qualified our findings into a scoring system to categorize the level of ecological disturbance. Additionally, this project integrated NDVI (Normalized Difference Vegetation Index) measurements by utilizing satellite imagery to offer a comprehensive overview of plant coverage across the refuge in relation to the dispersion of non-native ungulates. The results showed that sites where cattle and feral horses were present, showed significant signs of grazing, soil compaction, and lower percentages of plant coverage.

Sam Fertik

My art making practices this summer continually evolved as my connections to the Sev and New Mexico became stronger and more complex. Everywhere you look there was some new observation, and while very vast and open, this place is full of detailed biological happenings. 

Art can be a way to showcase and bring attention to details that might go unnoticed in passing. I decided to focus on plant systems for my art projects this summer. I used painting to investigate the textures and microstructures of plant leafs. This is a space where color is a product of structure and function. This project was not only great experience involving color theory and light use within the paintings, but also into botanical adaptations. The harsh environmental factor of sunlight forges a diverse array of life strategies among plants. These are evident in the trichomes, salt crystals, and waxes that are seen on plant surfaces in this semi-arid environment. Together these parts form a complex interface between solar radiation and the internal machinery of a plant where infinitely busy light interactions are occurring.

Hidden mostly beneath the ground, roots grow, twist, and search within a busy substrate. Guided by water and nutrients, they shape according to uncountable factors. This architecture inspired an exploration of line work through drawings and a final metal sculpture. The welded root system was made out of on site metal from past experiments.

Ellen Fritz

What Lives Underground: Exploration of Sevilleta Organic Material

Ripe prickly pear fruit, mineral-rich sediments, crumbly mushrooms, and the cactus-loving insect, Cochineal, were the muses of my work at the Sevilleta National Wildlife Refuge. I began by foraging these desert-dwelling organisms and sediments— collecting and identifying them— to create a library of the ecosystem around me in an attempt to understand how the harsh conditions of the desert forges uniquely resilient characteristics in its inhabitants. The need to burrow, to create interconnected havens underground, is one of these evolved behaviors; Both flora and fauna find their sanctuary in the soil, using branching structures— mazes of burrows and fractal root systems— to establish their place in the desert.

            I used these foraged elements to create pigments, dyes, inks, and paints, which culminated in tangible material explorations in the form of books and sculptural paintings. My process of recipe experimentation— grinding, blending, extracting, boiling— using Sevilleta plants, insects, fungi, and dirt revealed the intrinsically reactive nature of living things; A slight pH change turns the blood red cochineal into royal purple, an overcooked prickly pear dye becomes coral orange, the shaggy mane’s ink (unsurprisingly) begins to mold. These give testament to the organisms’ processes of growth, decay, and accumulation of individual cellular characteristics, building its internal structure throughout life and uncovering the ever-changing states of being after death.

Transmutation of living matter is no surprise, yet it yields fascination and wonder when it’s our hands revealing these properties hidden from the naked eye— properties only present through injection of heat, chemicals, and agitation. My work at the Sev strives to dissolve the human-nature barrier and show that elements of the diverse ecologies around us can be practically utilized to create, fabricate, educate, in the modern era of widespread industrial manufacturing in which the ecosystem is so far removed from its product.

Sara Garcia

My name is Sara Garcia, and I am a student from Grinnell College majoring in biology and sociology. I have spent my summer investigating the question of whether harvester ants (Pogonomyrmex spp.) collect and disperse creosote seeds. While this might seem like quite an obscure question to answer, it is increasingly important because of the changing landscape. For years, creosote has been encroaching on the native grassland to an extent that is not sufficiently explained by wind dispersal as previous literature has suggested. Because creosote encroachment is so drastically changing the ecosystem, contributing to things like increasing nighttime temperatures, it is important to understand how this is happening. While others have previously discounted ants and animals as potential dispersers of creosote due to the unpalatable compounds found in the creosote bush, I decided to explore whether their assumption was correct. To do this, I set up a cafeteria-style experiment where I set out petri dishes filled with sand and seeds within a wire cage that excluded other animals, then I waited three days and counted the remaining number of seeds in the petri dishes. I also conducted some observational studies of ant activity around a creosote bush. In the end, I found that harvester ants do in fact harvest and potentially disperse creosote seeds, thus providing us with new, exciting knowledge that can be used in future experiments to better understand the changing dynamics between grassland and shrubland ecosystems.

James Loomis

When I was told I would have the opportunity to establish some foundational research about the burrowing owls at the Sevilleta National Wildlife Refuge, I was most excited to be able to study such a charismatic animal. As I read more about them and began to spend time with them in the field, I quickly learned of the important role they play in the ecosystem and how much we could learn from them that could help inform future conservations decisions. While many avian groups are in decline, burrowing owls have persisted with stable populations despite distribution and range changes. They are of conservation concern due to habitat loss and fragmentation caused by agricultural encroachment and anthropogenic disturbance. Having the opportunity to study them in a more naturally managed environment allowed for insights into ecological interactions and dynamics of the food webs of which they are a part. I often try to consider how animals make their living, like humans, to better understand their role in an environment. Using trail cameras and direct observations in the early morning, I was able to describe their habitat requirements, their diet using owl pellets and observations, and their common behaviors that support their success. Understanding these life history traits can help direct management decisions that will protect not just these owls but also ecosystems they inhabit and the other organisms with which they interact. Hopefully studying these visually appealing animals can also make them a useful species for educational and public outreach and can help create a deeper appreciation for wildlife and nature.

Natalie Lucero

The Rio Grande flows through the Chihuahuan desert, creating an entirely new ecosystem in which plants and animals have diversified. Still, stressful conditions such as seasonal flooding and evaporation are threatening to native fauna. With such great stresses that cannot yet be alleviated, it is important that keystone species such as freshwater turtles are preserved. These turtles maintain the health of their systems, consuming harmful bacteria and dispersing seeds. Internal competition among the turtles has yet to be assessed in the portion of the Rio Grande that runs through Sevilleta National Wildlife Reserve. We performed an analysis of dietary habits to reveal competition status that can indicate the system’s sustainability. Stable isotope analysis of the species Chrysemys picta and Apalone spinifera showed no overlap in carbon or nitrogen levels between species. It was also found that the mass of a turtle did not significantly correlate with its N¹⁵ levels. This indicates that there is no competition between the two native turtle species. The data collected is part of a long term research project and will continue to be added to. This and future data collections will reveal trends and can be used to aid in conservation efforts and expand general knowledge. Should the population of a native species of turtle start to decline, knowing whether or not food competition is a contributing factor will allow for efforts to be more appropriately directed.

Kathy Nash

Parasitism within the plant kingdom is an intriguing phenomenon that has emerged independently at least twelve times in recorded history. While plant parasitism has garnered increasing attention in recent years, its exploration remains a relatively nascent field of ecological study, bearing wide-ranging implications. Predominantly, research has centered around agricultural parasites like dodder and striga, but the enigmatic influence of hemiparasitic plants on ecological plant communities remains a fertile ground for discovery. The initial inspiration for this project was to highlight the unique potential of parasitic plants in herbaria. These specimens hold a more extensive significance as they are framed as interconnected data streams, exemplifying the intricate web of relationships between parasites and hosts (Teixeira-Costa et al., 2023). This becomes especially crucial as such associations are exceptionally sensitive to the throes of global environmental change.

Driven by this dynamic backdrop, the project’s objectives crystallize into three pursuits: first, unraveling the impacts of Castilleja integra on the composition of its host plant communities; second, deciphering the variance in fitness across the expanse of C. integra’s habitat range; and third, unveiling the temporal and spatial dynamics of both the quantity and quality of preserved C. integra specimen. Contrary to our hypothesis, C. integra exhibited minimal effects on the richness and evenness of the local plant ecosystem. Furthermore, the herbarium study uncovered negligible variations in fitness along C. integra’s longitudinal range. Significantly, the project underscores the potential for refining C. integra collections by including root systems and the associated plant species, enhancing the quality of specimens amassed. In sum, this research casts light on the multifaceted interplay between parasitic plants and their hosts and underscores the value of herbaria as custodians of valuable ecological narratives.

Signe Renstrom

A Survey of Natural and Artificial Springs in the Northern Chihuahuan Desert

I am Signe Renstrom and I am from Ohio, and go to school at Eckerd College in St. Petersburg, Florida. I am super passionate about conservation biology and understanding how ecosystems work in order to implement proper restoration or conservation efforts. This summer I did just that. I research four different types of water sources on the Sevilleta in regards to invertebrate community composition, plant community, and water quality. Water is an important natural resource, especially in desert ecosystems. Spring and seeps in the Northern Chihuahuan Desert ecosystem provide many subsidies for native flora and fauna, have high rates of biodiversity, and are home for many endemic invertebrates. This is why this research is so important in order to figure out which water sources were the most beneficial to the Sevilleta Wildlife Refuge and which ones need the most restoration work. My research found the natural springs had the highest evenness, and highest plant cover, whereas concrete drinkers had the lowest evenness and plant cover. Most metal drinkers and concrete drinkers in terms of water quality were above the safe drinking limit of nitrates and nitrites. It was also found that artificial springs were the most productive, and I suggest for future restoration efforts that concrete and metal drinkers be restored back to artificial springs.

Erica Seguin

Global warming has caused many North American small mammal species to shift in geographic range. In places where similar species have come to co-occur, it is necessary to practice resource partitioning to avoid competition. In this study, we investigated differences in dietary ecology and co-occurrence among modern woodrats (N. albigula and N. micropus) at the Sevilleta National Wildlife Refuge and in fossil woodrats at Hall’s Cave. At the Sevilleta, we used camera traps to characterize food choices for Neotoma at three sites (one each in allopatry, one in sympatry). Using microCT-derived 3D lower tooth rows for N. albigula and N. micropus, we collected six ecomorphological dietary variables and identified diagnostic characters to identify fossil Neotoma teeth in the Hall’s Cave record. Camera-trapping cafeteria experiments at the Sevilleta found that the dietary differences between the two species are exaggerated in sympatry. 3D dental ecomorphology analyses revealed that modern Neotoma albigula possessed a significantly higher enamel:crown ratio than N. micropus. We also identified several external, anatomical differences between the species, enabling identification from lower first molars. Using ECR and external dental characters, we were able to determine when different Neotoma species existed in the Hall’s Cave fossil record. The stratigraphic ranges of N. albigula and N. micropus at Hall’s Cave show that they can co-exist for millennia. This research elucidates how shifting assemblages may compete or co-exist with one another as humans continue to transform the planet through land use changes and global warming.

Sam Veloz

The Effects of Dominant Species Removals on Soil Biogeochemistry in Two Semi-Arid Grasslands

Ever since I can recall, my fascination with science, particularly in the realm of medicine, has been unwavering. This passion led me to embark on a journey towards a degree in Biological Sciences, specializing in Biomedical Science. An unexpected turn occurred when I enrolled in an ecology course, sparking my interest in environmental sciences. This newfound curiosity made me consider pursuing it further at the graduate level.

With the intention of delving into this unexplored scientific domain, I decided to apply for the Sevilleta REU program. My goal was to acquire hands-on experience and in-depth knowledge in this unfamiliar field. This opportunity would enable me to broaden my horizons and step into the world of science that was previously beyond my familiarity.

I was engaged in a removal project as part of a specific segment within the comprehensive Sevilleta Long Term Ecological Research Program (LTER) which was started 28 years ago by Deb Peters. This program is dedicated to attaining a multi-decadal comprehension of dryland variations in the Northern Chihuahuan desert and Great Plains ecosystems. The focal point is investigating the impacts of altered monsoonal precipitation patterns on the biogeochemistry and subterranean activity of both the Chihuahuan Desert grassland and the Great Plains grasslands. Within these ecosystems, Bouteloua eriopoda (BE) predominantly thrives in the Chihuahuan Desert Grassland, while Bouteloua gracilis (BG) takes precedence in the Great Plains Grassland. The prevailing extreme drought conditions across these grasslands have led to heightened soil pH levels and an increased availability of essential soil nutrients, such as nitrate and phosphate. In an effort to deepen our comprehension of this intricate relationship, the primary objective of this project is to further illuminate the precise mechanisms through which climate change influences the subterranean ecosystem. This research for me is something I will be continuing throughout my last semester. This journey has proven to be an unforeseen opportunity, delivering far more than I had ever envisioned and surpassing my initial expectations.

Clara Zhou de Magalhaes

The creosote bush (Larrea tridentata) is an abundant desert shrub species in the American southwest. It is a vital host to many insect pollinators, including several specialist bee species. Like other flowering plants, creosote flowers provide a habitat for various bacterial and fungal communities. The extent to which the floral mycobiome affects pollinator fitness is still largely unclear, but there is growing interest in the effects of fungal volatiles on pollinators. The aim of this study was to investigate whether the creosote’s fungal-floral interactions play a role in attracting or repelling pollinators. Past research indicates that fungal volatiles are attractive to a broad range of insect taxons in an agricultural environment. However, these relationships may manifest differently in creosote grassland/shrubland environments at the Sevilleta National Wildlife Refuge. We isolated three yeast species from creosote flowers and grew them in Petri dishes. We placed insect traps baited with these fungi across three different transects, then identified the insects down to order once we collected them. Preliminary conclusions can be drawn from the results, which showed that flies and wasps were the most frequently represented insect groups found in the traps. Further work on this subject can help narrow down the direct impacts of these microbial organisms on bees and other pollinators. Other studies found that some fungi can aid larval development in bees while others are a major source of mortality. Should floral fungi negatively affect the fitness of bees, it would also negatively impact insect diversity, which is already threatened by multiple causes such as habitat loss and climate change. Therefore, studying how these fungal species benefit or hinder the pollinators’ fitness provides more insight into how endemic species respond to threats.