Life Sciences Commons^™

Landscape Scale: Inter- And Intraspecific Variation In Plant Interactions Along A Stress Gradient In The Sheep Range Of Nevada, Jordan Dowell

UNLV Theses, Dissertations, Professional Papers, and Capstones

Impending threats to shrubland ecosystems, posed by climate change, necessitate niche modeling efforts to project vegetation range shifts. However, efforts often remain unguided by individual-scale interspecific plant interactions. The stress gradient hypothesis posits that facilitation should increase in areas of high abiotic stress, only if the individuals are able to ameliorate the surrounding area via functional traits. The Sheep Range of Nevada was used to assess the role of functional traits as predictors of plant association. Larrea tridentata, Coleogyne ramosissima, and Artemisia nova were selected as shrubs with variable life history strategies and ranges in order to identify general patterns …

Habitat Use Of The Climate-Sensitive Snowshoe Hare (Lepus Americanus) In The Manistee National Forest In Michigan’S Lower Peninsula, Spencer D. West

Masters Theses

Snowshoe hares (Lepus americanus) are a wide-ranging lagomorph that are important forest herbivores and a popular game species throughout their range. Across the southern boundary of their geographic range, snowshoe hares are experiencing population declines and possible extirpation due to increased predation pressure driven by climate change induced camouflage mismatch, competition for forage, degraded and fragmented habitat. One method of reversing the negative trends in snowshoe hare distribution is to increase and improve available hare habitat. A specific habitat analysis for local regions will most effectively advise managers how to target habitat management. I radio-collared 11 snowshoe hares in the …

Changes In The Diet And Body Size Of A Small Herbivorous Mammal (Hispid Cotton Rat, Sigmodon Hispidus) Following The Late Pleistocene Megafauna Extinction, Catalina P. Tomé, Emma A. Elliott Smith, S. Kathleen Lyons, Seth D. Newsome, Felisa A. Smith

School of Biological Sciences: Faculty Publications

The catastrophic loss of large-bodied mammals during the terminal Pleistocene likely led to cascading effects within communities. While the extinction of the top consumers probably expanded the resources available to survivors of all body sizes, little work has focused on the responses of the smallest mammals. Here, we use a detailed fossil record from the southwestern United States to examine the response of the hispid cotton rat Sigmodon hispidus to biodiversity loss and climatic change over the late Quaternary. In particular, we focus on changes in diet and body size. We characterize diet through carbon (δ¹³C) and nitrogen …

Multi‐Scale Integration Of Tree Recruitment And Range Dynamics In A Changing Climate, Paige E. Copenhaver-Parry, Charles J. W. Carroll, Patrick H. Martin, Matthew V. Talluto

Faculty Publications - Department of Biological & Molecular Science

Aim: The rate and magnitude of climate‐induced tree range shifts may be influenced by range‐wide variation in recruitment, which acts as a bottleneck in tree range dynamics. Here, we compare range predictions made using standard species distribution models (SDMs) and an integrated metamodelling approach that assimilates data on adult occurrence, seedling recruitment dynamics, and seedling survival under both current and future climate, and evaluate the degree to which information provided by seedling data can improve predictions of range dynamics.

Location: The interior west region of the United States.

Time period: 1990–2015.

Major taxa studied: Five widespread conifer tree species.

Methods: …

Phenotypically Plastic Responses To Predation Risk Are Temperature Dependent, Thomas M. Luhring, Janna M. Vavra, Clayton E. Cressler, John Delong

School of Biological Sciences: Faculty Publications

Predicting how organisms respond to climate change requires that we understand the temperature dependence of fitness in relevant ecological contexts (e.g., with or without predation risk). Predation risk often induces changes to life history traits that are themselves temperature dependent. We explore how perceived predation risk and temperature interact to determine fitness (indicated by the intrinsic rate of increase, r) through changes to its underlying components (net reproductive rate, generation time, and survival) in Daphnia magna. We exposed Daphnia to predation cues from dragonfly naiads early, late, or throughout their ontogeny. Predation risk increased r differentially across temperatures …

The Stability Of Temperate Lakes Under The Changing Climate, Aleksey Paltsev

Electronic Thesis and Dissertation Repository

There is a collective prediction among ecologists that climate change will enhance phytoplankton biomass in temperate lakes. Yet there is noteworthy variation in the structure and regulating functions of lakes to make this statement challengeable and, perhaps, inaccurate. To generate a common understanding on the trophic transition of lakes, I examined the interactive effects of climate change and landscape properties on phytoplankton biomass in 12,644 lakes located in relatively intact forested landscapes. Chlorophyll-a (Chl-a) concentration was used as a proxy for phytoplankton biomass. Chl-a concentration was obtained via analyzing Landsat satellite imagery data over a 28-year period (1984-2011) and using …

The Association Between Dietary Niche Variation In Rodents And Climate Change Across The Paleocene-Eocene Thermal Maximum, Hannah K. Vermeer

Masters Theses

Mammalian teeth play a crucial role in food acquisition and breakdown and are therefore closely tied to dietary niche. This study reconstructed the diet of early Paleogene paramyid rodents across the Paleocene-Eocene Thermal Maximum (PETM) climatic event in an effort to understand the role of climate in mammalian dietary niche change. Dietary niches were quantified using three dental topographic measures: Dirichlet normal energy, relief index, and orientation patch count rotated. A Kruskal-Wallis test was conducted over eight time periods to determine if each of the dental topographic measures (i.e., diet) varied over time. Regression analysis of these measures with climatic …

Ecological And Morphological Response Of Rodents To Environmental Change Over The Late Quaternary, Catalina Tome

Biology ETDs

The rapid progression of modern climate change is already altering ecosystems worldwide. By employing the fossil record, we can investigate how animals responded to past climatic changes and biodiversity loss. The paleontological record of the late Quaternary (past ~22000 years) encompasses a period of considerable environmental change in North America. Rising temperatures and climatic fluctuations are coupled with the extinction of the majority of large bodied mammals on the landscape. The combination of climate and extinction events led to changes in vegetation and community structure which likely affected the resources available and interactions between the remaining mammals within communities. Here, …

Thermal Quality Explains Shift In Habitat Association From Forest To Clearings For Terrestrial-Breeding Frogs Along An Elevation Gradient In Colombia, Zachary Lange

Masters Theses

Tropical ectotherms are considered particularly sensitive to changes in the thermal environment from climate change and habitat alteration. Understanding how such species’ thermal physiology relates to their habitat associations in thermally heterogeneous landscapes may help us predict responses and develop sound conservation strategies for the future. We conducted a mark-recapture study of three terrestrial breeding anuran species (Pristimantis medemi, P. savagei, P. frater) in adjacent forest and anthropogenic clearings at field sites spread across seven elevations (415-1350 m asl) in the Colombian Andes. We also performed thermal preference and critical thermal maximum assays in the lab to investigate the relationship …

Heatwaves And Novel Host Consumption Increase Overwinter Mortality Of An Imperiled Wetland Butterfly, Mariana Abarca, Elise A. Larsen, Leslie Ries

Biological Sciences: Faculty Publications

Disruptive effects of climate change include range shifts, phenological mismatches among consumers and producers, and population declines. While these biological alterations have been widely documented, studies identifying specific mechanisms linking climate change to population declines are scarce. Extreme events, such as heatwaves can have devastating effects on living organisms and are increasing in frequency as Earth warms. Hence, understanding the effects of heatwaves on insects is necessary to inform conservation efforts and to develop predictions of population dynamics under future climate scenarios. Here, we experimentally evaluated the effects of heatwaves on the survival and phenology of the Baltimore Checkerspot (Euphydryas …

Dietary Plasticity In A Specialist Predator, The Gyrfalcon (Falco Rusticolus): New Insights Into Diet During Brood Rearing, Bryce W. Robinson, Travis L. Booms, Marc J. Bechard, David L. Anderson

Biology Faculty Publications and Presentations

Climate and landscape change are expected to affect species’ distributions and interactions, with potentially harmful consequences for specialist predators. Availability of optimal prey can affect reproductive success in raptors, especially in the Arctic, where dramatic differences in prey availability occur both within and between years. However, behavioral responses of dietary specialist, resident predators such as Gyrfalcons (Falco rusticolus) to changes in prey availability remain poorly understood. To improve understanding of how climate-driven changes in prey availability may affect diet of avian predators in the Arctic, we characterized Gyrfalcon diet on the Seward Peninsula, Alaska, in 2014 and 2015 …

Opportunities For Behavioral Rescue Under Rapid Environmental Change, Samuel B. Fey, David A. Vasseur, Karla Alujević, Kristy J. Kroeker, Michael L. Logan, Mary I. O'Connor, Volker H.W. Rudolf, John Delong, Scott Peacor, Rebecca L. Selden, A Sih, Susana Clusella‐Trullas

School of Biological Sciences: Faculty Publications

Laboratory measurements of physiological and demographic tolerances are important in understanding the impact of climate change on species diversity; however, it has been recognized that forecasts based solely on these laboratory estimates overestimate risk by omitting the capacity for species to utilize microclimatic variation via behavioral adjustments in activity patterns or habitat choice. The complex, and often context‐dependent nature, of microclimate utilization has been an impediment to the advancement of general predictive models. Here, we overcome this impediment and estimate the potential impact of warming on the fitness of ectotherms using a benefit/cost trade‐off derived from the simple and broadly …

Warming Up: Climate Change Related Shifts Of Mycorrhizal Fungal Communities In High Latitude Ecosystems, Megan Rae Devan

Biology ETDs

This dissertation examines how climate change affects mycorrhizal fungal communities in boreal and arctic ecosystems. In chapter one, I revealed that increases in fire severity and related increases in deciduous tree dominance result in greater Ascomycota relative abundance (RA) and subsequent declines in Basidiomycota RA. In chapter two I analyzed the effects of post-fire mycorrhizal fungal communites on host growth. There were trends at the fungal genus level that were largely reflected at the guild level across all hosts; however, there were some fungal genera that had the opposite effect on different host species. In chapter three, I found host …

Biogeographical Implications Of Climate Change For An Alpine Mammal, The American Pika, Marie Louise Westover

Biology ETDs

Anthropogenic climate change has already impacted a majority of species globally. The aim of this dissertation is to understand how climate and climate change influences animal ecology and evolution across space and time, using the American pika (Ochotona. princeps) as a model system. I investigate how pika body size, diet, and occupancy are influenced by different aspects of climate over space and time. Body size in O. princeps populations best correlates to precipitation and vegetation, rather than temperature. Our findings suggest that pika body size may be more related to vegetation and food availability than the direct effects …

Comparative Thermal Ecology Of Coastal And Inland Pacific Rattlesnakes (Crotalus Oreganus), Hayley Layne Crowell

Master's Theses

Global biodiversity is declining as a direct result of anthropogenic climate change. Ectothermic species have become focal organisms for studying the ecological effects of altered climates due to the clear relationship between environmental temperatures and ectotherms’ basic physiological functions. Historically, examinations of these effects have focused heavily on heliothermic lizards, and most others have tended to focus on single populations or sympatric species within a single community. Addressing the longterm energetic implications of environmental temperature variation will provide valuable insight into the cascading physiological effects that certain populations or species may experience as a result of altered climates.

In this …

Effects Of Increased Precipitation On The Life History Of Spring- And Autumn-Germinated Plants Of The Cold Desert Annual Erodium Oxyrhynchum (Geraniaceae), Yanfeng Chen, Xiang Shi, Lingwei Zhang, Jerry M. Baskin, Carol C. Baskin, Huiliang Liu, Daoyuan Zhang

Biology Faculty Publications

Future increased precipitation in cold desert ecosystems may impact annual/ephemeral plant species that germinate in both spring and autumn. Our primary aim was to compare the life history characteristics of plants from spring-germinating (SG) and autumn-germinating (AG) seeds of Erodium oxyrhynchum. Plants in field plots with simulated increases in precipitation of 0, 30 and 50 % in spring and summer were monitored to determine seedling survival, phenology, plant size, seed production and biomass accumulation and allocation. Germination characteristics were determined in the laboratory for seeds produced by plants in all increased precipitation treatments. Increased precipitation in spring significantly improved survival …

Changes In Spring Arrival Times: Climate Change And The Phenology Of Spring Bird Migration, Aaron Svedlow

Student Scholarship

Climate change and weather affect the phenology of bird migration; however, specific climatological factors associated with these observed effects have only recently been described. The relationship between local, regional, and global climate patterns and avian migration are increasingly important to understand due to the widespread, and potentially negative, implications (such as reduced fecundity) of rapid human induced climate change on bird populations. Migratory birds are under selective pressure to arrive at breeding areas at the optimal time to set up nesting territories and exploit seasonally abundant food resources, and because climate change has the potential to occur more rapidly than …

Characterization Of Psychromonas Aquimarina, A New Model Organism For Climate Change, Carrie Carpenter

Experiential Learning Projects

The current increase of average global temperature puts 25 to 35 percent of plant and animal species at an increased risk of extinction (Climate Change, 2018). Changing any environmental factor, such as increasing growth temperature, can significantly impact any organisms’ ability to survive. Because of the diversity of organisms on the planet, it is not feasible to study how each individually might adapt, but rather it is more efficient to study select organisms. This research focuses on a psychrophilic bacterium, Psychromonas aquimarina, which can survive in colder regions where most bacteria would not. This bacterium was chosen because climate change …

The Living Archive In The Anthropocene, Nora Almeida, Jen Hoyer

Publications and Research

This paper presents the concept of the living archive as a system which reflects how social behavior and cultural production are part of the Anthropocene. The authors explore how dominant narratives of both the Anthropocene and the archive work to consolidate power and maintain cultural and disciplinary divisions. The authors refute conceptions of the Anthropocene as a purely biophysical phenomenon that is alienated from cultural practice and of the archive as a comprehensive and nostalgic space. They then introduce the living archive as an alternative representational, creative, and reactive space and illustrate how the living archive can intervene in ecological …

Abundance And Species Diversity Hotspots Of Tracked Marine Predators Across The North American Arctic, David J. Yurkowski, Marie Auger-Méthé, Mark L. Mallory, Sarah N.P. Wong, Grant Gilchrist, Andrew E. Derocher, Evan Richardson, Nicholas J. Lunn, Nigel E. Hussey, Marianne Marcoux, Ron R. Togunov, Aaron T. Fisk, Lois A. Harwood, Rune Dietz, Aqqalu Rosing-Asvid, Erik W. Born, Anders Mosbech, Jérôme Fort, David Grémillet, Lisa Loseto

Great Lakes Institute for Environmental Research Publications

Aim: Climate change is altering marine ecosystems worldwide and is most pronounced in the Arctic. Economic development is increasing leading to more disturbances and pressures on Arctic wildlife. Identifying areas that support higher levels of predator abundance and biodiversity is important for the implementation of targeted conservation measures across the Arctic. Location: Primarily Canadian Arctic marine waters but also parts of the United States, Greenland and Russia. Methods: We compiled the largest data set of existing telemetry data for marine predators in the North American Arctic consisting of 1,283 individuals from 21 species. Data were arranged into four species groups: …

Incorporating Temperature And Precipitation Extremes Into Process-Based Models Of African Lepidoptera Changes The Predicted Distribution Under Climate Change, Madeleine G. Barton, John S. Terblanche, Brent J. Sinclair

Biology Publications

Terrestrial insects are responding to ongoing climate change. While these responses have been primarily linked to rising temperatures, insects are sensitive to desiccation, and the impacts of altered precipitation regimes remain relatively unexplored. Here, we develop a mechanistic model of survival and performance responses to both temperature and desiccation stress, focussing on Lepidoptera in Africa, where a general understanding of such responses to climate change is urgently required. We run the model with climate data from general circulation models at daily time intervals under current (2011–2015) and projected future (2046–2050) climate scenarios. We first simulate four hypothetical, but typical, Lepidoptera …

Seed Germination Responses To Seasonal Temperature And Drought Stress Are Species‐Specific But Not Related To Seed Size In A Desert Steppe: Implications For Effect Of Climate Change On Community Structure, Fengyan Yi, Zhaoren Wang, Carol C. Baskin, Jerry M. Baskin, Ruhan Ye, Hailian Sun, Yuanyuan Zhang, Xuehua Ye, Guofang Liu, Xuejun Yang, Zhenying Huang

Biology Faculty Publications

Investigating how seed germination of multiple species in an ecosystem responds to environmental conditions is crucial for understanding the mechanisms for community structure and biodiversity maintenance. However, knowledge of seed germination response of species to environmental conditions is still scarce at the community level. We hypothesized that responses of seed germination to environmental conditions differ among species at the community level, and that germination response is not correlated with seed size. To test this hypothesis, we determined the response of seed germination of 20 common species in the Siziwang Desert Steppe, China, to seasonal temperature regimes (representing April, May, June, …

Creative Citizen Science Illuminates Complex Ecological Responses To Climate Change, Abraham J. Miller-Rushing, Amanda S. Gallinat, Richard B. Primack

Biology Faculty Publications

Climate change is causing the timing of key behaviors (i.e., phenology) to shift differently across trophic levels and among some interacting organisms (e.g., plants and pollinators, predators and prey), suggesting that interactions among species are being disrupted (1, 2). Studying the phenology of interactions, however, is difficult, which has limited researchers’ ability to zero in on changes in specific interactions or on the consequences of mismatches. In PNAS, Hassall et al. (3) use a combination of citizen science techniques to investigate the effects of climate change on dozens of specific interactions. They focus on a Batesian mimicry complex involving stinging …

Local Adaptation, Genetic Divergence, And Experimental Selection In A Foundation Grass Across The Us Great Plains’ Climate Gradient, Matthew Galliart, Nora Bello, Mary Knapp, Jesse Poland, Paul St Amand, Sara Baer, Brian Maricle Ph.D., Adam B. Smith, Loretta Johnson

Biological Sciences Faculty Publications

Many prior studies have uncovered evidence for local adaptation using reciprocal transplant experiments. However, these studies are rarely conducted for a long enough time to observe succession and competitive dynamics in a community context, limiting inferences for long-lived species. Furthermore, the genetic basis of local adaptation and genetic associations with climate has rarely been identified. Here, we report on a long-term (6-year) experiment conducted under natural conditions focused on Andropogon gerardii, the dominant grass of the North American Great Plains tallgrass ecosystem. We focus on this foundation grass that comprises 80% of tallgrass prairie biomass and is widely used in …

Effects Of Thermal Stress On Amount, Composition, And Antibacterial Properties Of Coral Mucus, Rachel M. Wright, Marie E. Strader, Heather M. Genuise, Mikhail Matz

Biological Sciences: Faculty Publications

Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, CA, United States of America ABSTRACT The surface mucus layer of reef-building corals supports feeding, sediment clearing, and protection from pathogenic invaders. As much as half of the fixed carbon supplied by the corals' photosynthetic symbionts is incorporated into expelled mucus. It is therefore reasonable to expect that coral bleaching (disruption of the coralfialgal symbiosis) would affect mucus production. Since coral mucus serves as an important nutrient source for the entire reef community, this could have substantial ecosystemwide consequences. In this study, we examined the effects of heat …

Influence Of Climate Change And Prescribed Fire On Habitat Suitability And Abundance Of The High-Elevation Endemic Cow Knob Salamander (Plethodon Punctatus), Carl David Jacobsen

Graduate Theses, Dissertations, and Problem Reports

Amphibians are facing global declines due to climate change, loss and degradation of habitat, invasive species, and disease. The Appalachian region of the eastern USA is a global biodiversity hotspot for salamanders, which are considered keystone species that influence nutrient dynamics in terrestrial and aquatic food webs. There are high rates of salamander endemism in the Appalachian region, with many species restricted to isolated, high elevation areas. The Cow Knob Salamander (Plethodon punctatus) is one such species. It is only found at elevations >675 m (most populations are above 900 m) on Shenandoah Mountain, North Mountain, and Nathaniel …

Interactive Effects Of Salinity And Inundation On Native Spartina Foliosa, Invasive S. Densiflora And Their Hybrid From San Francisco Estuary, California, Blanca Gallego-Trevar, Brenda J. Grewell, Caryn J. Futrell, Rebecca E. Drenovsky, Jesus M. Castillo

2019 Faculty Bibliography

Sea level rise (SLR) associated with climate change is intensifying permanent submersion and salinity in salt marshes. In this scenario, hybridization between native and invasive species may result in hybrids having greater tolerance of abiotic stress factors than their parents. Thus, understanding the responses of native and invasive halophytes and their hybrids to interacting physiological stresses imposed by SLR is key to native species conservation. We analysed how salinity, inundation depth and their interaction impact the functional traits of native and invasive cordgrass species and their hybrid (genus Spartina; Poaceae).

Factors Influencing Zooplankton Communities In Small Arctic Lakes, Northwest Territories, Jasmina Vucic

Theses and Dissertations (Comprehensive)

The Canadian Arctic has been warming at an unprecedented rate, causing significant changes to the environment. At the same time, continued development in the north has increased the demand for gravel extraction used to construct and maintain infrastructure such as highways. The development of roadways and gradual loss of permafrost in Canada’s north has led to changes in water quality, including increased calcium, conductivity, and nutrients. In addition, gravel extraction has led to the formation of artificial gravel pit lakes. Research has yet to determine how physical and chemical changes associated with development and permafrost thaw might impact zooplankton, and …

Dispersal As A Buffer Against Zooplankton Community Change In Response To Fluctuating Salinity Levels On The Great Plains, Mercedes Huynh

Theses and Dissertations (Comprehensive)

The North American Great Plains is home to thousands of closed-basin lakes that are sensitive to changes in hydrology. Climate change models predict increased aridity in this region over the coming century, which is expected to lead to higher salinity levels in many freshwater lakes. Increases in salinity levels may impact zooplankton communities, as laboratory experiments show that many freshwater species have a low tolerance for elevated salinity levels, and field data demonstrate that salinity is the primary factor structuring aquatic communities on the Great Plains. Changes to zooplankton communities could lead to a trophic cascade based on their important …