Life Sciences Commons^™

Climate Change-Associated Declines In Water Clarity Impair Feeding By Common Loons, Walter H. Piper, Max R. Glines, Kevin C. Rose

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Climate change has myriad impacts on ecosystems, but the mechanisms by which it affects individual species can be difficult to pinpoint. One strategy to discover such mechanisms is to identify a specific ecological factor related to survival or reproduction and determine how that factor is affected by climate. Here we used Landsat imagery to calculate water clarity for 127 lakes in northern Wisconsin from 1995 to 2021 and thus investigate the effect of clarity on the body condition of an aquatic visual predator, the common loon (Gavia immer). In addition, we examined rainfall and temperature as potential predictors …

A Remote Sensing Approach To Assess The Historical Invasion Of Phragmites Australis In A Brackish Coastal Marsh, Jason S. Hagani, John Y. Takekawa, Steven C. Chappell, Richelle L. Tanner, Adrienne R. Ernst, Karin M. Kettenring

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Introduction: Coastal estuarine wetlands provide important habitats for a variety of endemic flora and fauna but are particularly vulnerable to biological invasions. Regular monitoring of changes in these vulnerable wetlands has become increasingly important for effective management, especially considering threats from climate change effects and human disturbance. Historical analyzes of plant invasions may guide targeted management strategies to eradicate harmful species. Estimating the distribution of invasive species has never been more accessible with the improved availability of high-resolution data and innovations in remote sensing, estimating the distribution of invasive species has never been more accessible.

Methods: We assessed the spread …

Who Are We? Highlighting Nuances In Asian American Experiences In Ecology And Evolutionary Biology, K. H. Nguyen, A. K. Akiona, C. C. Chang, V. B. Chaudhary, S. J. Cheng, S. M. Johnson, S. S. Kahanamoku, A. Lee, E. E. Deleon Sanchez, L. M. Segui, Richelle L. Tanner

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

"As ecologists and evolutionary biologists, it is important to recognize that issues surrounding AAPI do not exist in a vacuum and that these issues affect some of our students and colleagues in and outside of the classroom and lab. Recently, anti-Asian racism has been brought to the forefront of US society. Though media attention has primarily focused on how COVID-19 fears motivated both violent and nonviolent racist incidents against East Asians in 2020 (e.g., Chinese and Taiwanese Americans) (Tessler et al. 2020), attacks on other AAPI groups, such as South and Southeast Asians (e.g., Filipino, Pakistani, and Vietnamese Americans) (Truong …

Kelp Morphology And Herbivory Are Maintained Across Latitude Despite Geographic Shift In Kelp-Wounding Herbivores, Nicholas P. Burnett, Eric J. Armstrong, Rosemary Romero, Charlotte C. Runzel, Richelle L. Tanner

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Herbivores can drastically alter the morphology of macroalgae by directly consuming tissue and by inflicting structural wounds. Wounds can result in large amounts of tissue breaking away from macroalgae, amplifying the damage initially caused by herbivores. Herbivores that commonly wound macroalgae often occur over only a portion of a macroalga’s lifespan or geographic range. However, we know little about the influence of these periodic or regional occurrences of herbivores on the large-scale seasonal and geographical patterns of macroalgal morphology. We used the intertidal kelp Egregia menziesii to investigate how the kelp’s morphology and the prevalence of two prominent kelp-wounding herbivores …

Empowering Hope-Based Climate Change Communication Techniques For The Gulf Of Maine, Aimee Bonanno, Megan Ennes, Jennifer A. Hoey, Emily Moberg, Sarah-Mae Nelson, Nette Pletcher, Richelle L. Tanner

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

The Gulf of Maine is one of the fastest warming marine areas on the planet: The industries and creatures that call it home face an unprecedented shift in their interactions and existence. Scientists, policy makers, and practitioners often want to communicate to the public about the seriousness of the situation to encourage mitigation and adaptation. Many standard communication strategies that rely on fear and scientific authority alone—rather than comprehensive explanations that include solutions—can leave audiences feeling overwhelmed and disengaged, instead of hopeful and motivated to act. In this practice bridge, we showcase a social science research-based climate change communication “tool-kit” …

The Role Of Dislodgement In The Territorial Ecology Of The Owl Limpet, Lottia Gigantea, Ryan T. Kabala, Natalie Swinford, Maria J. Mason, William G. Wright

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Ascertaining the risks and benefits of different behaviors is a central goal of research on territoriality. Although most territorial behavior is ritualized, with concomitant reduced risks for both residents and intruders, this ritualization is generally found to be underpinned by rare, highly consequential, interactions. The agonistic behavior of the intertidal owl limpet, Lottia gigantea, involves defense of a feeding territory, and includes a relatively explosive thrusting response by territory holders against intruding conspecifics. We here ask whether this thrusting behavior is capable of entirely dislodging intruders from their rocky wave-swept substratum, thereby ridding the resident of future challenges by …

Plasticity Of Foot Muscle And Cardiac Thermal Limits In The Limpet Lottia Limatula From Locations With Differing Temperatures, Terrance Wang, Richelle L. Tanner, Eric J. Armstrong, David R. Lindberg, Jonathon H. Stillman

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Species distributions are shifting in response to increased habitat temperatures as a result of ongoing climate change. Understanding variation in physiological plasticity among species and populations is important for predicting these distribution shifts. Interspecific variation in intertidal ectotherms’ short-term thermal plasticity has been well established. However, intraspecific variation among populations from differing thermal habitats remains a question pertinent to understanding the effects of climate change on species’ ranges. In this study, we explored upper thermal tolerance limits and plasticity of those limits using a foot muscle metric and 2 cardiac metrics (Arrhenius breakpoint temperature, ABT, and flatline temperature, FLT) in …

High Heat Tolerance Is Negatively Correlated With Upper Thermal Tolerance Plasticity In North Eastern Pacific Nudibranch Mollusks, Eric J. Armstrong, Richelle L. Tanner, Jonathon H. Stillman

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Rapid ocean warming may alter habitat suitability and population fitness for marine ectotherms. Susceptibility to thermal perturbations will depend in part on plasticity of a species’ upper thermal limits of performance (CT_max). However, we currently lack data regarding CT_max plasticity for several major marine taxa, including nudibranch mollusks, thus limiting predictive responses to habitat warming for these species. In order to determine relative sensitivity to future warming, we investigated heat tolerance limits (CT_max), heat tolerance plasticity (acclimation response ratio), thermal safety margins, temperature sensitivity of metabolism, and metabolic cost of heat shock in nine species …

No Evidence For Trace Metal Limitation On Anaerobic Carbon Mineralization In Three Peatland Soils, Jason K. Keller, Jillian Wade

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Peatlands store roughly one-third of the terrestrial soil carbon and release the potent greenhouse gas methane (CH₄) to the atmosphere, making these wetlands among the most important ecosystems in the global carbon cycle. Despite their importance, the controls of anaerobic decomposition of organic matter to carbon dioxide (CO₂) and CH₄ within peatlands are not well understood. It is known, however, that the enzymes responsible for CH₄ production require cobalt, iron and nickel, and there is a growing appreciation for the potential role of trace metal limitation in anaerobic decomposition. To explore the possibility of …

What Controls Variation In Carbon Use Efficiency Among Amazonian Tropical Forests?, Christopher E. Doughty, Gregory R. Goldsmith, Nicolas Raab, Cecile A. J. Girardin, Filio Farfan-Amezquita, Walter Huaraca-Huasco, Javier E. Silva-Espejo, Alejandro Araujo-Murakami, Antonio C. L. Da Costa, Wanderley Rocha, David Galbraith, Patrick Meir, Dan B. Metcalfe, Yadvinder Malhi

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Why do some forests produce biomass more efficiently than others? Variations in Carbon Use Efficiency (CUE: total Net Primary Production (NPP)/ Gross Primary Production (GPP)) may be due to changes in wood residence time (Biomass/NPP_wood), temperature, or soil nutrient status. We tested these hypotheses in 14, one ha plots across Amazonian and Andean forests where we measured most key components of net primary production (NPP: wood, fine roots, and leaves) and autotrophic respiration (R_a; wood, rhizosphere, and leaf respiration). We found that lower fertility sites were less efficient at producing biomass and had higher rhizosphere respiration, …

Can Functional Traits Predict Plant Community Response To Global Change?, Sarah Kimball, Jennifer L. Funk, Marko J. Spasojevic, Katharine N. Suding, Scot Parker, Michael K. Goulden

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

One primary goal at the intersection of community ecology and global change biology is to identify functional traits that are useful for predicting plant community response to global change. We used observations of community composition from a long-term field experiment in two adjacent plant communities (grassland and coastal sage shrub) to investigate how nine key plant functional traits were related to altered water and nitrogen availability following fire. We asked whether the functional responses of species found in more than one community type were context dependent and whether community-weighted mean and functional diversity were significantly altered by water and nitrogen …

Testing The Trait-Based Community Framework: Do Functional Traits Predict Competitive Outcomes?, Jennifer L. Funk, Amelia Wolf

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Plant traits can be used to understand a range of ecological processes, including competition from invasive species. The extent to which native and invasive species are competing via limiting similarity or trait hierarchies has important implications for the management of invaded communities. We screened 47 native species that co-occur with Festuca perennis, a dominant invader in California serpentine grassland, for traits pertaining to resource use and acquisition. We then grew F. perennis with ten species spanning a range of functional similarity in pairwise competition trials. Functionally similar species did not have a strong adverse effect on F. perennis performance …

Evolutionary Responses Of Invasive Grass Species To Variation In Precipitation And Soil Nitrogen, Monica A. Nguyen, Amy E. Ortega, Quoc L. Nguyen, Sarah Kimball, Michael L. Goulden, Jennifer L. Funk

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

1.Global climate models suggest that many ecosystems will experience reduced precipitation over the next century and the consequences for invasive plant performance are largely unknown. Annual invasive species may be able to quickly evolve traits associated with drought escape or tolerance through rapid genetic changes.

2.We investigated the influence of five years of water and nitrogen manipulations on trait values in a southern California grassland system. Seeds from two annual grass species (Avena barbata, Bromus madritensis) were collected from experimental plots and grown in a common environment over two generations. We measured 14 physiological, morphological, phenological, and …

Temporal Variation In Optical Properties Of Chromophoric Dissolved Organic Matter (Cdom) In Southern California Coastal Waters With Nearshore Kelp And Seagrass, Catherine D. Clark, Warren J. De Bruyn, Paige Aiona

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Optical properties of chromophoric dissolved organic matter (CDOM) were measured in surf zone waters in diurnal field studies at a Southern California beach with nearshore kelp and seagrass beds and intertidal plant wrack. Absorption coefficients (aCDOM(300 nm)) ranged from 0.35 m21 to 3.7 m21 with short-term variability<1 h, increases at ebb and flood tides and higher values (6 m21) during an offshore storm event. Spectral slopes (S) ranged from 0.0028 nm21 to 0.017 nm21, with higher values after the storm; S was generally inversely correlated with aCDOM(300 nm). 3-D excitation–emission matrix spectra (EEMs) for samples with lower S values had humic-type peaks associated with terrestrial material (A, C), marine microbial material (M) and protein peaks, characteristic of freshly produced organic material. Samples with high S values had no or reduced protein peaks, consistent with aged material. Fluorescent indexes (f450/f500 >2.5, BIX>1.1) were consistent with microbial aquatic sources. Leachates of senescent kelp and seagrass had protein and humic-type EEM peaks. After solar simulator irradiation (4 h), protein peaks rapidly photochemically degraded, humic-type peak C increased in intensity and peak M disappeared. Optical characteristics of kelp leachates were most similar to field samples, …

Shifts In Attack Behavior Of An Important Kelp Forest Predator Within Marine Reserves, J. S. Berriman, M. C. Kay, D. C. Reed, A. Rassweiler, D. A. Goldstein, William G. Wright

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Marine reserves have become increasingly valuable tools with which to manage ecosystems. These reserves consistently restore populations of top predators, often reducing availability of their favored prey. We hypothesized that such prey reduction in reserves causes protected predators to alter their attack behavior to include less palatable prey, potentially amplifying top-down effects on community structure. To test this hypothesis, we presented the relatively unpalatable sea hare Aplysia californica to freely foraging spiny lobsters Panulirus interruptus in 4 marine no-take reserves, each paired with an adjacent fished area. We found that lobsters only attacked sea hares inside reserves, where lobster density …

Plant Functional Traits Of Dominant Native And Invasive Species In Mediterranean-Climate Ecosystems, Jennifer L. Funk, Rachel J. Standish, William D. Stock, Fernando Valladares

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

The idea that dominant invasive plant species outperform neighboring native species through higher rates of carbon assimilation and growth is supported by several analyses of global datasets. However, theory suggests that native and invasive species occurring in low-resource environments will be functionally similar, as environmental factors restrict the range of observed physiological and morphological trait values. We measured resource-use traits in native and invasive plant species across eight diverse vegetation communities distributed throughout the five Mediterranean-climate regions, which are drought-prone and increasingly threatened by human activities including the introduction of exotic species. Traits differed strongly across the five regions. In …

Solid-Phase Organic Matter Reduction Regulates Anaerobic Decomposition In Bog Soil, Jason K. Keller, Kimberly K. Takagi

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Peatlands store globally significant amounts of carbon and are important sources of the greenhouse gas methane (CH4) to the atmosphere. However, for reasons which are not well understood, many peatland soils produce smaller amounts of CH4 than theoretically predicted, and carbon dioxide (CO2) produced during anaerobic decomposition in peatland soils cannot be accounted for by commonly measured microbial processes. Here we show that the reduction of solid-phase organic matter (i.e., humic substances) suppresses CH4 production in a bog soil and can be responsible for 33–61% of the total carbon mineralization in this soil. These results demonstrate that the reduction of …

Can Resource-Use Traits Predict Native Vs. Exotic Plant Success In Carbon Amended Soils?, Robert J. Steers, Jennifer L. Funk, Edith B. Allen

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Productivity in desert ecosystems is primarily limited by water followed by nitrogen availability. In the deserts of southern California, nitrogen additions have increased invasive annual plant abundance. Similar findings from other ecosystems have led to a general acceptance that invasive plants, especially annual grasses, are nitrophilous. Consequently, reductions of soil nitrogen via carbon amendments have been conducted by many researchers in a variety of ecosystems in order to disproportionately lower invasive species abundance, but with mixed success. Recent studies suggest that resource-use traits may predict the efficacy of such resource manipulations; however, this theory remains largely untested. We report findings …

Lobster Attack Induces Sensitization In The Sea Hare, Aplysia Californica, Amanda J. Watkins, Daniel A. Goldstein, Lucy C. Lee, Christina J. Pepino, Scott L. Tillett, Francis E. Ross, Elizabeth M. Wilder, Virginia A. Zachary, William G. Wright

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Studies of the neural mechanisms of learning, especially of sensitization, have benefitted from extensive research on the model species, Aplysia californica (hereafter Aplysia). Considering this volume of literature on mechanisms, it is surprising that our understanding of the ecological context of sensitization in Aplysia is completely lacking. Indeed, the widespread use of strong electric shock to induce sensitization (an enhancement of withdrawal reflexes following noxious stimulation) is completely unnatural and leaves unanswered the question of whether this simple form of learning has any ecological relevance. We hypothesized that sublethal attack by a co-occurring predator, the spiny lobster, Panulirus interruptus, might …

Salt Marshes As A Source Of Chromophoric Dissolved Organic Matter (Cdom) To Southern California Coastal Waters, Catherine D. Clark, Liannea P. Litz, Stanley B. Grant

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

To determine chromophoric dissolved organic matter (CDOM) sources in Southern California coastal waters, optical properties of a river outlet and adjacent tidally flushed salt marshes were monitored (dry season; June July 2001). Average absorption coefficients doubled at ebb vs. flood tides (4.8 +/- 1.5 vs. 2.1 +/- 0.9 m(-1); 300 nm), suggesting significant salt marsh CDOM inputs into coastal waters. Average spectral slopes were not statistically different for any sites or tides (0.010 +/- 0.002 nm(-1)), consistent with salt marsh CDOM dominating coastal waters. Three-dimensional fluorescence excitation-emission matrices (EEMs) at ebb tide showed contributions from terrestrial, protein, and marine humic-like …

Effect Of Wave Action On Movement In The Owl Limpet, Lottia Gigantea, In Santa Cruz, California, William G. Wright, James W. Nybakken

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

The critical role of wave energy in the ecology of nearshore organisms is widely accepted, based primarily on biotic correlations over large scales of time and space. Much less is known about how large waves impact the behavioral ecology of individual organisms. Theoretical considerations and measurements of tenacity predict that intertidal gastropods should minimize the chances of dislodgement during periods of high waves by remaining stationary. We tested this prediction by observing a population of the owl limpet, Lottia gigantea G. B. Sowerby I, 1834, in a range of sea conditions. We found the proportion of the population moving during …

Pathways Of Anaerobic Carbon Cycling Across An Ombrotrophic–Minerotrophic Peatland Gradient, Jason K. Keller, Scott D. Bridgham

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Peatland soils represent globally significant stores of carbon, and understanding carbon cycling pathways in these ecosystems has important implications for global climate change. We measured aceticlastic and autotrophic methanogenesis, sulfate reduction, denitrification, and iron reduction in a bog, an intermediate fen, and a rich fen in the Upper Peninsula of Michigan for one growing season. In 3-d anaerobic incubations of slurried peat, denitrification and iron reduction were minor components of anaerobic carbon mineralization. Experiments using 14C-labeled methanogenic substrates showed that methanogenesis in these peatlands was primarily through the aceticlastic pathway, except early in the growing season in more ombrotrophic peatlands, …

Nutrient Control Of Microbial Carbon Cycling Along An Ombrotrophicminerotrophic Peatland Gradient, Jason K. Keller, Angela K. Bauers, Scott D. Bridgham, Laurie E. Kellogg, Colleen M. Iversen

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Future climate change and other anthropogenic activities are likely to increase nutrient availability in many peatlands, and it is important to understand how these additional nutrients will influence peatland carbon cycling. We investigated the effects of nitrogen and phosphorus on aerobic CH4 oxidation, anaerobic carbon mineralization (as CO2 and CH4 production), and anaerobic nutrient mineralization in a bog, an intermediate fen, and a rich fen in the Upper Peninsula of Michigan. We utilized a 5-week laboratory nutrient amendment experiment in conjunction with a 6-year field nutrient fertilization experiment to consider how the relative response to nitrogen and phosphorus differed among …