Digital Commons Network^™

Larval Fish Export In Response To Varying Compensating Gate Discharge At The Sault Rapids, St. Marys River, Signe F.K. Vandrunen

All NMU Master's Theses

The St. Marys River (SMR) forms the border between Michigan, USA and Ontario, Canada connecting lakes Superior and Huron. Discharge is controlled by a compensating gate system upstream of the SMR rapids. Because spring and summer discharge fluctuates widely, resource managers required information on how flow variability influences larval fish drift. I estimated annual larval fish export in relation to variable discharge during 2018-2021 and compared results to published habitat model predictions. Mean discharge and water temperature were lowest in 2021 and highest in 2019. Water warming rates during high discharge differed from low discharge trends. Across years, I identified …

Evaluating Acid-Aluminum Stress In Streams Of The Northeastern U.S. At Watershed, Fish Community And Physiological Scales, Benjamin J. Zdasiuk, Celia Y. Chen, Stephen D. Mccormick, Keith H. Nislow, Joel Singley, John T. Kelly

Arts & Sciences Faculty Publications

In spite of overall improvements in air and water quality, biological stress from low pH and high concentrations of inorganic aluminum continue to impact fish and fish habitat in northeastern North America, with independent and interactive effects on individuals, populations and communities. Integrative indicators can therefore be useful in monitoring both impact and recovery across multiple scales. Using coupled water chemistry (pH, conductivity, and base cation and inorganic aluminum concentration), geographic (site elevation and watershed area) and biological (fish diversity, fish abundance, gill aluminum concentration and gill physiology) data, we developed an integrated indicator of acid-aluminum stress across the White …

Persistence And Expansion Of Cryptic Endangered Red Wolf Genomic Ancestry Along The American Gulf Coast, Bridgett M. Vonholdt, Kristin E. Brzeski, Matthew L. Aardema, Christopher J. Schell, Linda Y. Rutledge, Steven R. Fain, Amy C. Shutt, Anna Linderholm, William J. Murphy

Department of Biology Faculty Scholarship and Creative Works

Admixture and introgression play a critical role in adaptation and genetic rescue that has only recently gained a deeper appreciation. Here, we explored the geographical and genomic landscape of cryptic ancestry of the endangered red wolf that persists within the genome of a ubiquitous sister taxon, the coyote, all while the red wolf has been extinct in the wild since the early 1980s. We assessed admixture across 120,621 single nucleotiode polymorphism (SNP) loci genotyped in 293 canid genomes. We found support for increased red wolf ancestry along a west-to-east gradient across the southern United States associated with historical admixture in …

College Of Natural Sciences Newsletter, September & October 2022, College Of Natural Sciences

College of Natural Sciences Newsletters and Reports

Volume 3, Issue 6

Page 1 Dean's Message
Page 2 Awards & Recognition
Page 3 Midwest Regional ACS Meeting
Page 4 North Central ASM Meeting
Page 5 Geography Department Travel
Page 6-7 Media Coverage of CNS
Page 7 REMAST Program at SDState receives national spotlight
Page 8 Celebrating the lives of those who touched the College
Page 9 Innovative Learning Spaces
Page 10 Open PRAIRIE Data
Page 11 2022 CNS Scholarship Brunch
Page 12-14 Fall 2022 Outreach Events

Impacts Of Algal Morphology And Water Flow On Macroalgal Microplastic Capture, Cheyenne M. Adams

Honors College Theses

Microplastic pollution is a major area of concern in marine environments, especially as microplastics enter the food web. This study used pipe cleaners and two lichen species as algal mimics, and Chaetomorpha sp. and Chondrus crispus as model algal species to test the effects of morphology and biomass on microbead and foam capture. This study also utilized two different water flow methods: vortices and waves. Results suggest that water flow, as well as biomass and morphology, play a role in microplastic capture in macroalgae. For all mimics and algal species, except Cladonia lichens, turfs with increased biomass and length showed …

Experimental And Observational Evidence Of Negative Conspecific Density Dependence In Temperate Extomycorrhizal Trees, Fiona V. Jevon, Dayna De La Cruz, Joseph A. Lamanna, Ashley K. Lang, David A. Orwig, Sydne Record, Paige V. Kouba, Matthew P. Ayres, Jaclyn H. Matthes

Biological Sciences Faculty Research and Publications

Conspecific negative density dependence (CNDD) promotes tree species diversity by reducing recruitment near conspecific adults due to biotic feedbacks from herbivores, pathogens, or competitors. While this process is well-described in tropical forests, tests of temperate tree species range from strong positive to strong negative density dependence. To explain this, several studies have suggested that tree species traits may help predict the strength and direction of density dependence: for example, ectomycorrhizal-associated tree species typically exhibit either positive or weaker negative conspecific density dependence. More generally, the strength of density dependence may be predictably related to other species-specific ecological attributes such as …

Post-Fire Seed Dispersal Of A Wind-Dispersed Shrub Declined With Distance To Seed Source, Yet Had High Levels Of Unexplained Variation, Cara Applestein, T. Trevor Caughlin, Matthew J. Germino

Biology Faculty Publications and Presentations

Plant-population recovery across large disturbance areas is often seed-limited. An understanding of seed dispersal patterns is fundamental for determining natural-regeneration potential. However, forecasting seed dispersal rates across heterogeneous landscapes remains a challenge. Our objectives were to determine (i) the landscape patterning of post-disturbance seed dispersal, and underlying sources of variation and the scale at which they operate, and (ii) how the natural seed dispersal patterns relate to a seed augmentation strategy. Vertical seed trapping experiments were replicated across 2 years and five burned and/or managed landscapes in sagebrush steppe. Multi-scale sampling and hierarchical Bayesian models were used to determine the …

Integrated Xenosurveillance Of Loa Loa, Wuchereria Bancrofti, Mansonella Perstans And Plasmodium Falciparum Using Mosquito Carcasses And Faeces: A Pilot Study In Cameroon, Joseph Pryce, Nils Pilotte, Benjamin Menze, Allison R. Sirois, Michael Zulch, Jean Pierre Agbor, Steven A. Williams, Charles S. Wondji, Lisa Reimer

Biological Sciences: Faculty Publications

Background Community presence of loiasis must be determined before mass drug administration programmes for lymphatic filariasis and onchocerciasis can be implemented. However, taking human blood samples for loiasis surveillance is invasive and operationally challenging. A xenosurveillance approach based on the molecular screening of mosquitoes and their excreta/feces (E/F) for Loa loa DNA may provide a non-invasive method for detecting the community presence of loiasis. Methods We collected 770 wild mosquitoes during a pilot study in a known loiasis transmission area in Mbalmayo, Cameroon. Of these, 376 were preserved immediately while 394 were kept in pools to collect 36-hour E/F samples …

Evolution Of Immune Function In Response To Dietary Macronutrients In Male And Female Decorated Crickets, Corinne Letendre, Alejandro Rios-Villamil, Alexandria Williams, James Rapkin, Scott K. Sakaluk, Clarissa M. House, John Hunt

Faculty Publications – Biological Sciences

Although dietary macronutrients are known to regulate insect immunity, few studies have examined their evolutionary effects. Here, we evaluate this relationship in the cricket Gryllodes sigillatus by maintaining replicate populations on four diets differing in protein (P) to carbohydrate (C) ratio (P‐ or C‐biased) and nutritional content (low‐ or high‐nutrition) for >37 generations. We split each population into two; one maintained on their evolution diet and the other switched to their ancestral diet. We also maintained populations exclusively on the ancestral diet (baseline). After three generations, we measured three immune parameters in males and females from each population. Immunity was …

County-Level Societal Predictors Of Covid-19 Cases And Deaths Changed Through Time In The United States: A Longitudinal Ecological Study, Philip J. Bergmann, Nathan A. Ahlgren, Rosalie A. Torres Stone

Biology

People of different racial/ethnic backgrounds, demographics, health, and socioeconomic characteristics have experienced disproportionate rates of infection and death due to COVID-19. This study tests if and how county-level rates of infection and death have changed in relation to societal county characteristics through time as the pandemic progressed. This longitudinal study sampled monthly county-level COVID-19 case and death data per 100,000 residents from April 2020 to March 2022, and studied the relationships of these variables with racial/ethnic, demographic, health, and socioeconomic characteristics for 3125 or 97.0% of U.S. counties, accounting for 96.4% of the U.S. population. The association of all county-level …

Evaluation Of Sedimentary Bacterial Community Dynamics And Contamination Assessment Of Lower Des Plaines River, Philips O. Akinwole, Madeline C. Draper, Amerti Guta, Mahaila J. Martin

Biology Faculty publications

Urban rivers often contain elevated concentrations of contaminants such as organic pollutants and heavy metals which can be amplified in lotic ecosystems receiving effluents from wastewater treatment plants (WWTP). However, the impact of WWTPs on the microbial parameters of the urban river sediments has not been well documented compared to urban surface water. Collecting sediment samples at five different locations over a 9,000 m transect during four sampling periods, we investigated spatiotemporal variations of microbial parameters in sediments of lower Des Plaines River; the largest effluent-dominated stream in the United States and the effects of sediment physicochemical properties on the …

Weather And Climate Change Drive Annual Variation Of Reproduction By An Aerial Insectivore, Michael T. Murphy, Lucas J. Redmond, Amy C. Dolan, Nathan W. Cooper, Karen Shepherdson, Christopher Michael Chutter, Sarah Cancellieri

Biology Faculty Publications and Presentations

For many bird species, but especially aerial insectivores, reproduction depends on weather. Climate change is likely to intensify effects, but with uncertain consequences. We report 22 years of data on Eastern Kingbird (Tyrannus tyrannus) reproduction for two populations located in different hygric environments undergoing climate change; mesic central New York, USA, (NY; 12 years) and xeric southeastern Oregon, USA, (OR: 10 years). Laying date became earlier with increasing temperature in the 30-day period preceding laying in identical fashion at both sites, and in years of early laying, clutch size was larger, length of laying season increased, and failed …

Agr2-Associated Er Stress Promotes Adherent-Invasive E. Coli Dysbiosis And Triggers Cd103+ Dendritic Cell Il-23-Dependent Ileocolitis, Monica Viladomiu, Manirath Khounlotham, Belgin Dogan, Svetlana F. Lima, Ahmed Elsaadi, Emre Cardakli, Jim G. Castellanos, Charles Ng, Jeremy Herzog, Alexi A. Schoenborn, Melissa Ellermann, Bo Liu, Shiying Zhang, Ajay S. Gulati, R. Balfour Sartor, Kenneth W. Simpson, Steven M. Lipkin, Randy S. Longman

Faculty Publications

Endoplasmic reticulum (ER) stress is associated with Crohn’s disease (CD), but its impact on host-microbe interaction in disease pathogenesis is not well defined. Functional deficiency in the protein disulfide isomerase anterior gradient 2 (AGR2) has been linked with CD and leads to epithelial cell ER stress and ileocolitis in mice and humans. Here, we show that ileal expression of AGR2 correlates with mucosal Enterobactericeae abundance in human inflammatory bowel disease (IBD) and that Agr2 deletion leads to ER-stress-dependent expansion of mucosal-associated adherent-invasive Escherichia coli (AIEC), which drives Th17 cell ileocolitis in mice. Mechanistically, our data reveal that AIEC-induced epithelial cell …

Population Density And Reproductive Seasonality Of Tryonia Cheatumi (Gastropoda: Cochliopidae), The Phantom Tryonia, Kathryn E. Perez, Nina Noreika, Chad Norris, Marty Kelly, Melissa Lopez, Christina Ortega, Salma Ruiz Sandoval, Samantha Gonzalez, Weston Nowlin

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

We studied population density, population size, and reproductive seasonality of the Phantom Tryonia, Tryonia cheatumi (Pilsbry, 1935). This endangered freshwater snail is found only in the San Solomon Spring system, a cienega, or karst-based, arid-land freshwater spring system, in western Texas, USA. We sampled populations at seven locations in the system seasonally over a 2-yr period. San Solomon Spring, the system's largest spring and modified into a swimming pool, had the largest population of T. cheatumi, with an estimated 49 million individuals and a mean density as high as 23,626 ± 39,030 (individuals/m2 ± SD). There were seasonal differences …

Hydrologic And Environmental Thresholds In Stream Fish Assemblage Structure Across Flow Regimes, J. Tyler Fox, Daniel D. Magoulick

Biological Sciences Faculty Publications and Presentations

The characteristic pattern of variation in flow magnitude, frequency, duration, timing, and rate of change defines the flow regime of rivers and streams and is a key driver of ecosystem processes in fluvial ecosystems. Under-standing how freshwater biotic assemblages change across gradients of hydrology and anthropogenic-source disturbance in different streamflow regimes is crucial to managing for sustainable environmental flows and watershed conservation. We compiled long-term (1916-2016) occurrence records for fishes collected in the Ouachita-Ozark Interior Highlands and West Gulf Coastal Plain streams, together with hydrologic metrics calculated from daily streamflow data measured at USGS stream gauging stations (n = 111), …

Removal Of Heavy Metals From Stormwater Runoff Using Granulated Drinking Water Treatment Residuals, Viravid Na Nagara, Dibyendu Sarkar, Evert J. Elzinga, Rupali Datta

Michigan Tech Publications, Part 1

Stormwater runoff is a significant source of heavy metals, including cadmium (Cd), chromium (Cr), and nickel (Ni), which pose ecological and human health problems. Various filter media have been evaluated for heavy metal removal from stormwater via adsorption, most involving chemical- or energy-intensive processes. Aluminum-based drinking water treatment residuals (WTR), a non-hazardous byproduct of drinking water treatment, are an inexpensive sorbent for heavy metals. However, the low permeability of WTR is a problem and requires mixing with sand and carbon materials to improve flow; but such amendments also reduce its sorption capacity. To overcome this problem, a granulated WTR sorbent …

Influence Of Plant Density On Rainfall Interception By Spartina Alterniflora, Hannah K. Longaberger

Honors College Theses

Abstract

Spartina alterniflora is an abundant plant in eastern US and Gulf coast salt marshes; it is important in maintaining a diverse ecosystem. Salt marshes are impacted by rainstorms, which may affect erosion events. This project examined the partitioning of rainfall on single plants of various sizes and on central plants within different canopy densities of S. alterniflora. By calculating the rain stemflow (SF), throughfall (TF), and water adhered to the stem in S. alterniflora, we gained insight to rainfall partitioning with different plant features. My research found no statistically significant relationship between different plant features and SF, TF, …

Clearance Of Hiv-1 Or Siv Reservoirs By Promotion Of Apoptosis And Inhibition Of Autophagy: Targeting Intracellular Molecules In Cure-Directed Strategies, Min Chen, Min Li, Marietta M Budai, Andrew P Rice, Jason T Kimata, Mahesh Mohan, Jin Wang

Faculty, Staff and Students Publications

The reservoirs of the HIV display cellular properties resembling long-lived immune memory cells that could be exploited for viral clearance. Our interest in developing a cure for HIV stems from the studies of immunologic memory against infections. We and others have found that long-lived immune memory cells employ prosurvival autophagy and antiapoptotic mechanisms to protect their longevity. Here, we describe the rationale for the development of an approach to clear HIV-1 by selective elimination of host cells harboring replication-competent HIV (SECH). While reactivation of HIV-1 in the host cells with latency reversing agents (LRAs) induces viral gene expression leading to …

Effect Of Carnosol On G Protein-Coupled Receptor Signaling In Cancer Cells, Laith Jehad Ahmad Abudawood

Theses

Carnosol is a plant polyphenol compound known for its beneficial properties against human diseases such as cancer and diabetes. However, the exact molecular and cellular mechanisms involved, and its molecular targets are not fully known. Carnosol was shown to bind and to modulate specific intracellular signaling proteins in cancer cell lines. In this study, we hypothesized that carnosol may pharmacologically target specific cell surface receptors including G Protein-Coupled Receptors (GPCRs) and Receptor Tyrosine Kinase (RTKs). Therefore, we tested the pharmacological effect of carnosol on the following receptors: Insulin Receptor (IR), Chemokine CXCL12 Receptor (CXCR4), Angiotensin II (AngII) Receptor (AT1R), Glucagon-Like …

In-Vitro Cell Culture Model To Determine Toxic Effects Of Soil Arsenic Due To Direct Dermal Exposure, Manas Warke, Madeline English, Laura De Marchi, Rohan Deep Sarkar, Srinivas Kannan, Rupali Datta, Smitha Rao

Michigan Tech Publications, Part 1

Arsenic (As) is one of the most toxic environmental pollutants, classified as a Class I carcinogen. Anthropogenic activities have led to an increase in As contamination of soils. Using animal models to study the health impacts of As is time and cost-prohibitive, hence attempts have been made to develop in-vitro cell culture models. However, most studies so far have not represented realistic environmental exposure conditions. We exposed Human Immortalized Keratinocyte (HaCaT) and Primary Human Dermal Fibroblasts (HDFa) cells to the water-soluble fraction of arsenic extracted from As spiked Immokalee soil to study the effect of soil As on skin cells. …

Improving The Growth Performance Of The Mangrove Avicennia Marina Seedlings Using Plant Growth Promoting Actinobacteria, Alanoud Abdulla Al Shamsi

Theses

The combination of commercial fish emulsion (FE) and plant growth-promoting actinobacteria capable of producing plant growth regulators (PGRs) was evaluated as a biofertilizer to enhance growth and development of grey mangrove (Avicennia marina) in the United Arab Emirates. In vitro studies identified the rhizosphere-competent Streptomyces griseorubens UAE1 (Sg) that was able to solubilize phosphorus, produce auxins, cytokinins, gibberellic acid, polyamines, and 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase. Growth promotion, nutrient contents and PGR levels in tissues of treated mangrove plants with fish emulsion and/or S. griseorubens UAE1 were further assessed in vivo. Under greenhouse and natural open-field nursery conditions, …

Maternal Effects On Growth Parameters Of Chloris Gayana Under Co2 Enrichment, Ahmed Adnan Mohammed Mashli

Theses

Rhodes grass, Chloris gayana, is commonly used forage plant for grazers, livestock, and cattle. It significantly improves soil fertility and its overall structure by preventing nematode flourishment in soil. It is also used as a cover crop to upgrade soil health by reducing soil erosion and increasing water availability. The present study assessed the effects of CO₂ on the growth, development and maternal effects of C. gayana. The experimental setup was made in such a way that the potential impacts of CO₂ can be measured on the eco-physiological growth of C. gayana by studying successive generations. Generation 1 …

Heterodimerization Between Chemokine Receptors Cxcr4 And Ccr7 And Its Role In Cancer, Maryam Naveed Muhammad Tariq

Theses

In physiology, the functional and physical interactions between cell surface receptors for signal molecules such as hormones, neurotransmitters, and cytokines, provides an important mechanism of diversity and regulation of signal transduction. Therefore, investigating the functional interactions between these receptors is of great importance for understanding their role in physiology and pathophysiology with potential application in drug discovery. In this context, numerous evidences support the implication of two chemokine receptors, CXCR4 and CCR7, in many cancer types. In this study, we hypothesized that the functional, and perhaps the physical interaction, occurring between CXCR4 and CCR7 may constitute one of the key …

Screening For Endophytic Actinobacteria To Enhance Growth And Salinity Tolerance Of Tomato Plants In The United Arab, Amira Hamdy Hassan

Theses

Salinity is one of the most decisive environmental factors limiting the productivity of crop plants, mainly in arid and semi-arid regions. An eco-friendly technology can be used to boost crop production in saline areas by using plant growth-bacteria. Endophytic actinobacteria that produce the enzyme 1-Aminocyclopropane-1-Carboxylic acid (ACC) Deaminase (ACCD) can modulate the levels of Ethylene (ET) in plants to reduce the effect of abiotic stresses including high salt stress. The main objectives of this study were to: (1) Evaluate endophytic actinobacterial isolates from healthy tomato plants cultivated in the UAE that are capable of producing ACCD in vitro; (2) …

Impacts Of Intermediate And Long-Term Vitamin D Deficiency On The Murine Gastric Epithelial Cells And Acid Secretion, Shaima Raji Sirajudeen

Dissertations

The biological functions of vitamin D (VD) are diverse. It influences immunological response, cell proliferation and differentiation, and calcium homeostasis. However, over one billion people globally are VD deficient. The VD receptors, VDR and PDIA3, mediate the biological activities of VD. Studies on the biological roles of VD are numerous but very little on the stomach. The stomach is divided into three main parts – forestomach, corpus and antrum. Gastric glands, which make up the functional units of the stomach, are made up of numerous cell lineages and are located in the corpus and antrum, which are the glandular parts …

A Hierarchy Of Interactions Between Pathogenic Virus And Vertebrate Host, Robert Friedman

Faculty Publications

This review is of basic models of the interactions between a pathogenic virus and vertebrate animal host. The interactions at the population level are described by a predatory-prey model, a common approach in the ecological sciences, and depend on births and deaths within each population. This ecological perspective is complemented by models at the genetical level, which includes the dynamics of gene frequencies and the mechanisms of evolution. These perspectives are symmetrical in their relatedness and reflect the idealized forms of processes in natural systems. In the latter sections, the general use of deep learning methods is discussed within the …

Comparison Of Protein Extraction Protocols And Allergen Mapping From Black Soldier Fly Hermetia Illucens, Utpal Bose, James A. Broadbent, Angéla Juhász, Shaymaviswanathan Karnaneedi, Elecia B. Johnston, Sally Stockwell, Keren Byrne, Vachiranee Limviphuvadh, Sebastian Maurer-Stroh, Andreas L. Lopata, Michelle L. Colgrave

Research outputs 2022 to 2026

Exploration of important insect proteins — including allergens — and proteomes can be limited by protein extraction buffer selection and the complexity of the proteome. Herein, LC-MS/MS-based proteomics experiments were used to assess the protein extraction efficiencies for a suite of extraction buffers and the effect of ingredient processing on proteome and allergen detection. Discovery proteomics revealed that SDS-based buffer yields the maximum number of protein groups from three types of BSF samples. Bioinformatic analysis revealed that buffer composition and ingredient processing could influence allergen detection. Upon applying multi-level filtering criteria, 33 putative allergens were detected by comparing the detected …

Administration Of Broadly Neutralizing Anti-Hiv-1 Antibodies At Art Initiation Maintains Long-Term Cd8+ T Cell Immunity, Miriam Rosás-Umbert, Jesper D. Gunst, Marie H. Pahus, Rikke Olesen, Mariane H. Schleimann, Paul W. Denton, Victor Ramos, Adam R. Ward, Natalie N. Kinloch, Dennis C. Copertino, Tuixent Escribà, Anuska Llano, Zabrina L. Brumme, R. Brad Jones, Beatriz Mothe, Christian Brander, Julie Fox, Michel C. Nussenzweig, Sarah Fidler, Marina Caskey, Martin Tolstrup, Ole S. Søgaard

Biology Faculty Publications

In simian-human immunodeficiency virus (SHIV)-infected non-human primates, broadly neutralizing antibodies (bNAbs) against the virus appear to stimulate T cell immunity. To determine whether this phenomenon also occurs in humans we measured HIV-1-specific cellular immunity longitudinally in individuals with HIV-1 starting antiviral therapy (ART) with or without adjunctive bNAb 3BNC117 treatment. Using the activation-induced marker (AIM) assay and interferon-γ release, we observe that frequencies of Pol- and Gag-specific CD8+ T cells, as well as Gag-induced interferon-γ responses, are significantly higher among individuals that received adjunctive 3BNC117 compared to ART-alone at 3 and 12 months after starting ART. The observed changes in …

Ca2+ Entry Units In A Superfast Fish Muscle, James Matthew Kittelberger, Clara Franzini-Armstrong, Simona Boncompagni

Biology Faculty Publications

Over the past two decades, mounting evidence has demonstrated that a mechanism known as store-operated Ca2+ entry (SOCE) plays a crucial role in sustaining skeletal muscle contractility by facilitating Ca2+ influx from the extracellular space during sarcoplasmic reticulum (SR) Ca2+ depletion. We recently demonstrated that, in exercised fast-twitch muscle from mice, the incidence of Ca2+ entry units (CEUs), newly described intracellular junctions between dead-end longitudinal transverse tubular (T-tubule) extensions and stacks of sarcoplasmic reticulum (SR) flat cisternae, strictly correlate with both the capability of fibers to maintain contractions during fatigue and enhanced Ca2+ influx via SOCE. Here, we tested the …

Plant Responses To Drought In A Semiarid Grassland: An Isotopic Approach, Elizabeth V. Fain

Biology ETDs

Dryland ecosystems are facing unprecedented climate extremes as a result of global climate change. Water is the most limiting factor in dryland ecosystems, therefore plants in drylands have developed crucial water-use strategies for drought survival. It is important to understand plant physiological responses to water stress as drylands are projected to experience more frequent, severe droughts in the coming decades. To test how plants respond to drought in a semiarid grassland, we measured δ13C, δ15N, and C/N ratio of common C3 and C4 plants (Bouteloua gracilis, B. eriopoda, Pleuraphis jamesii, Salsola tragus, Machaeranthera pinnatifida, …