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Full-Text Articles in Life Sciences

Synecological Response Of Spring Benthic Prokaryotes And Macroinvertebrates To Paleozoic Roof Pendant-Derived Calcium, Ariel D. Friel, Khaled Pordel, Zachary Meyers, Cale O. Seymour, Nicole J. Thomas, Fred M. Philips, Jeffrey R. Knott, Donald W. Sada, Laura Rademacher, Marty Frisbee, Brian P. Hedlund May 2023

Synecological Response Of Spring Benthic Prokaryotes And Macroinvertebrates To Paleozoic Roof Pendant-Derived Calcium, Ariel D. Friel, Khaled Pordel, Zachary Meyers, Cale O. Seymour, Nicole J. Thomas, Fred M. Philips, Jeffrey R. Knott, Donald W. Sada, Laura Rademacher, Marty Frisbee, Brian P. Hedlund

Life Sciences Faculty Research

Despite the ecological significance of desert springs, little is known about relationships between spring hydrogeochemistry and ecology, particularly over multiple trophic levels. Here, we surveyed microbial communities (bacteria and archaea) and benthic macroinvertebrate (BMI) communities in springs that recharge through granitoid bedrock in Owens Valley, CA, to determine whether subtle geochemical differences imparted by metamorphosed roof pendant weathering in the source area affect spring ecosystems. Relative to other springs, roof-pendant-recharged springs were characterized by elevated (1) Ca2+/Na+, Ca2+/Mg2+, and divalent/monovalent cation ratios, (2) relative abundance of taxa inferred to be benthic aerobes and prosthecate/stalked bacteria, and (3) abundance and diversity …


Editorial: Ecology, Metabolism And Evolution Of Archaea-Perspectives From Proceedings Of The International Workshop On Geo-Omics Of Archaea, Brian P. Hedlund, Chuanlun Zhang, Fengping Wang, Christian Rinke, William F. Martin Jan 2022

Editorial: Ecology, Metabolism And Evolution Of Archaea-Perspectives From Proceedings Of The International Workshop On Geo-Omics Of Archaea, Brian P. Hedlund, Chuanlun Zhang, Fengping Wang, Christian Rinke, William F. Martin

Life Sciences Faculty Research

To facilitate global efforts in addressing fundamental questions related to the biology of archaea, an international consortium of experts organized the International Workshop on Geo-Omics of Archaea (IWGOA), with the overarching themes of Ecology/Biogeochemistry, Metabolism, and Evolution. The IWGOA was held in Shenzhen, China, from October 25th to 27th, 2019. The meeting was attended by more than 200 attendees from China, Japan, USA, Australia, Germany, and France. Some of the most exciting oral and poster presentations made at the IWGOA are celebrated in this Research Topic Figure 1. The 21 manuscripts herein span different aspects of archaeal biology in both …


The Aboveground And Belowground Growth Characteristics Of Juvenile Conifers In The Southwestern United States, N. L. Pirtel, R. M. Hubbard, J. B. Bradford, T. E. Kolb, M. E. Litvak, Scott Abella, S. L. Porter, Matthew Petrie Nov 2021

The Aboveground And Belowground Growth Characteristics Of Juvenile Conifers In The Southwestern United States, N. L. Pirtel, R. M. Hubbard, J. B. Bradford, T. E. Kolb, M. E. Litvak, Scott Abella, S. L. Porter, Matthew Petrie

Life Sciences Faculty Research

Juvenile tree survival will play an important role in the persistence of coniferous forests and woodlands in the southwestern United States (SWUS). Vulnerability to climatic and environmental stress declines as trees grow, such that larger, more deeply rooted juveniles are less likely to experience mortality. It is unclear how juvenile conifers partition the aboveground and belowground components of early growth, if growth differs between species and ecosystem types, and what environmental factors influence juvenile carbon allocation above- or belowground. We developed a novel data set for four juvenile conifer groups (junipers, piñon pines, ponderosa pines, firs; 1121 juveniles sampled, 221 …


Ancestral Polymorphisms Shape The Adaptive Radiation Of Metrosideros Across The Hawaiian Islands, Jae Young Choi, Xiaoguang Dai, Ornob Alam, Julie Z. Peng, Priyesh Rughani, Scott Hickey, Eoghan Harrington, Sissel Juul, Julien F. Ayroles, Michael D. Purugganan, Elizabeth A. Stacy Sep 2021

Ancestral Polymorphisms Shape The Adaptive Radiation Of Metrosideros Across The Hawaiian Islands, Jae Young Choi, Xiaoguang Dai, Ornob Alam, Julie Z. Peng, Priyesh Rughani, Scott Hickey, Eoghan Harrington, Sissel Juul, Julien F. Ayroles, Michael D. Purugganan, Elizabeth A. Stacy

Life Sciences Faculty Research

Some of the most spectacular adaptive radiations begin with founder populations on remote islands. How genetically limited founder populations give rise to the striking phenotypic and ecological diversity characteristic of adaptive radiations is a paradox of evolutionary biology. We conducted an evolutionary genomics analysis of genus Metrosideros, a landscape-dominant, incipient adaptive radiation of woody plants that spans a striking range of phenotypes and environments across the Hawaiian Islands. Using nanopore-sequencing, we created a chromosome-level genome assembly for Metrosideros polymorpha var. incana and analyzed whole-genome sequences of 131 individuals from 11 taxa sampled across the islands. Demographic modeling and population …


A Whole-Genome Scan For Association With Invasion Success In The Fruit Fly Drosophila Suzukii Using Contrasts Of Allele Frequencies Corrected For Population Structure, Laure Olazcuaga, Anne Loiseau, Hugues Parrinello, Mathilde Paris, Antoine Fraimout, Christelle Guedot, Lauren M. Diepenbrock, Marc Kenis, Jinping Zhang, Xiao Chen, Nicolas Borowiec, Benoit Facon, Heidrun Vogt, Donald K. Price, Heiko Vogel, Benjamin Prud'homme, Arnaud Estoup, Mathieu Gautier Apr 2021

A Whole-Genome Scan For Association With Invasion Success In The Fruit Fly Drosophila Suzukii Using Contrasts Of Allele Frequencies Corrected For Population Structure, Laure Olazcuaga, Anne Loiseau, Hugues Parrinello, Mathilde Paris, Antoine Fraimout, Christelle Guedot, Lauren M. Diepenbrock, Marc Kenis, Jinping Zhang, Xiao Chen, Nicolas Borowiec, Benoit Facon, Heidrun Vogt, Donald K. Price, Heiko Vogel, Benjamin Prud'homme, Arnaud Estoup, Mathieu Gautier

Life Sciences Faculty Research

Evidence is accumulating that evolutionary changes are not only common during biological invasions but may also contribute directly to invasion success. The genomic basis of such changes is still largely unexplored. Yet, understanding the genomic response to invasion may help to predict the conditions under which invasiveness can be enhanced or suppressed. Here, we characterized the genome response of the spotted wing drosophila Drosophila suzukii during the worldwide invasion of this pest insect species, by conducting a genome-wide association study to identify genes involved in adaptive processes during invasion. Genomic data from 22 population samples were analyzed to detect genetic …


Floral Variation Across Three Varieties Of The Landscape-Dominant Tree Metrosideros Polymorpha (Myrtaceae): Insights From A Hawaii Island Common Garden, Elizabeth A. Stacy, Melissa A. Johnson Dec 2020

Floral Variation Across Three Varieties Of The Landscape-Dominant Tree Metrosideros Polymorpha (Myrtaceae): Insights From A Hawaii Island Common Garden, Elizabeth A. Stacy, Melissa A. Johnson

Life Sciences Faculty Research

Premise of research: Metrosideros polymorpha is a landscape-dominant tree species endemic to the Hawaiian Islands. Although the group is famous for its ecological amplitude and variation in vegetative characters, little attention has been paid to variation in its “shaving brush” flowers, which occur in inflorescences of diverse sizes and colors. We aimed to determine whether the floral variation observed in natural populations is heritable and how this variation is distributed across environments and varieties of the species. Methodology: We measured seven floral traits in 93 adult trees representing three varieties of M. polymorpha in a common garden on the island …


Artificial Nightlight Alters The Predator–Prey Dynamics Of An Apex Carnivore, Mark A. Ditmer, David C. Stoner, Clinton D. Francis, Jesse R. Barber, James D. Forster, David M. Choate, Kirsten E. Ironside, Kathleen M. Longshore, Kent R. Hersey, Randy T. Larsen, Brock R. Mcmillan, Daniel D. Olson, Alyson M. Andreasen, Jon P. Beckmann, P. Brandon Holton, Terry A. Messmer, Neil H. Carter Oct 2020

Artificial Nightlight Alters The Predator–Prey Dynamics Of An Apex Carnivore, Mark A. Ditmer, David C. Stoner, Clinton D. Francis, Jesse R. Barber, James D. Forster, David M. Choate, Kirsten E. Ironside, Kathleen M. Longshore, Kent R. Hersey, Randy T. Larsen, Brock R. Mcmillan, Daniel D. Olson, Alyson M. Andreasen, Jon P. Beckmann, P. Brandon Holton, Terry A. Messmer, Neil H. Carter

Life Sciences Faculty Research

Artificial nightlight is increasingly recognized as an important environmental disturbance that influences the habitats and fitness of numerous species. However, its effects on wide‐ranging vertebrates and their interactions remain unclear. Light pollution has the potential to amplify land‐use change, and as such, answering the question of how this sensory stimulant affects behavior and habitat use of species valued for their ecological roles and economic impacts is critical for conservation and land‐use planning. Here, we combined satellite‐derived estimates of light pollution, with GPS‐data from cougars Puma concolor (n = 56), mule deer Odocoileus hemionus (n = 263) and locations of cougar‐killed …


Resilience And Alternative Stable States After Desert Wildfires, Scott R. Abella, Dominic M. Gentilcore, Lindsay P. Chiquoine Sep 2020

Resilience And Alternative Stable States After Desert Wildfires, Scott R. Abella, Dominic M. Gentilcore, Lindsay P. Chiquoine

Life Sciences Faculty Research

Improving models of community change is a fundamental goal in ecology and has renewed importance during global change and increasing human disturbance of the biosphere. Using the Mojave Desert (southwestern United States) as a model system, invaded by nonnative plants and subject to wildfire disturbances, we examined models of resilience, alternative stable states, and convergent-divergent trajectories for 36 yr of plant community change after 31 wildfires in communities dominated by the native shrubs Larrea tridentata or Coleogyne ramosissima. Perennial species richness on average was fully resilient within 23 yr after disturbance in both community types. Perennial cover was fully resilient …


Analysis Of Genomic Sequence Data Reveals The Origin And Evolutionary Separation Of Hawaiian Hoary Bat Populations, Corinna A. Pinzari, Lin Kang, Pawel Michalak, Lars S. Jermiin, Donald K. Price, Frank J. Bonaccorso Aug 2020

Analysis Of Genomic Sequence Data Reveals The Origin And Evolutionary Separation Of Hawaiian Hoary Bat Populations, Corinna A. Pinzari, Lin Kang, Pawel Michalak, Lars S. Jermiin, Donald K. Price, Frank J. Bonaccorso

Life Sciences Faculty Research

We examine the genetic history and population status of Hawaiian hoary bats (Lasiurus semotus), the most isolated bats on Earth, and their relationship to northern hoary bats (Lasiurus cinereus), through whole-genome analysis of single-nucleotide polymorphisms mapped to a de novo-assembled reference genome. Profiles of genomic diversity and divergence indicate that Hawaiian hoary bats are distinct from northern hoary bats, and form a monophyletic group, indicating a single ancestral colonization event 1.34 Ma, followed by substantial divergence between islands beginning 0.51 Ma. Phylogenetic analysis indicates Maui is central to the radiation across the archipelago, with the southward expansion to Hawai‘i and …


Microbiome Shifts Associated With The Introduction Of Wild Atlantic Horseshoe Crabs (Limulus Polyphemus) Into A Touch-Tank Exhibit, Ariel D. Friel, Sean A. Neiswenter, Cale O. Seymour, Lauren Rose Bali, Ginger Mcnamara, Fabian Leija, Jack Jewell, Brian P. Hedlund Jul 2020

Microbiome Shifts Associated With The Introduction Of Wild Atlantic Horseshoe Crabs (Limulus Polyphemus) Into A Touch-Tank Exhibit, Ariel D. Friel, Sean A. Neiswenter, Cale O. Seymour, Lauren Rose Bali, Ginger Mcnamara, Fabian Leija, Jack Jewell, Brian P. Hedlund

Life Sciences Faculty Research

The Atlantic horseshoe crab (Limulus polyphemus) is a common marine aquarium species and model organism for research. There is potential monetary and conservation value in developing a stable captive population of horseshoe crabs, however, one major impediment to achieving captivity is a lack of knowledge regarding captive diseases. We utilized 16S rRNA gene amplicon sequencing to track changes in the microbiomes of four body locations in three wild-caught (tracked over 14 months in captivity) and three tank-acclimated (>2 years in captivity) adult L. polyphemus in a touch tank at Shark Reef Aquarium at Mandalay Bay in Las Vegas, NV. …


Microrna Profiling In The Weddell Seal Suggests Novel Regulatory Mechanisms Contributing To Diving Adaptation, Luca Penso-Dolfin, Wilfried Haerty, Allyson Hindle, Federica Di Palma Apr 2020

Microrna Profiling In The Weddell Seal Suggests Novel Regulatory Mechanisms Contributing To Diving Adaptation, Luca Penso-Dolfin, Wilfried Haerty, Allyson Hindle, Federica Di Palma

Life Sciences Faculty Research

Background:The Weddell Seal (Leptonychotes weddelli) represents a remarkable example of adaptation to diving among marine mammals. This species is capable of diving... (See full abstract in article).


Local‐Regional Similarity In Drylands Increases During Multiyear Wet And Dry Periods And In Response To Extreme Events, Matthew D. Petrie, D. P.C. Peters, N. D. Bruss, W. Ji, H. M. Savoy Dec 2019

Local‐Regional Similarity In Drylands Increases During Multiyear Wet And Dry Periods And In Response To Extreme Events, Matthew D. Petrie, D. P.C. Peters, N. D. Bruss, W. Ji, H. M. Savoy

Life Sciences Faculty Research

Climate change is predicted to impact ecosystems through altered precipitation (PPT) regimes. In the Chihuahuan Desert, multiyear wet and dry periods and extreme PPT pulses are the most influential climatic events for vegetation. Vegetation responses are most frequently studied locally, and regional responses are often unclear. We present an approach to quantify correlation of PPT and vegetation responses (as Normalized Difference Vegetation Index [NDVI]) at the Jornada ARS‐LTER site (JRN; 550 km2 area) and the surrounding dryland region (from 0 to 500 km distance; 400,000 km2 study area) as a way to understand regional similarity to locally observed patterns. We …


Persistence And Turnover In Desert Plant Communities During A 37-Yr Period Of Land Use And Climate Change, Scott R. Abella, Ross J. Guida, Chris L. Roberts, Carrie M. Norman, James S. Holland Jul 2019

Persistence And Turnover In Desert Plant Communities During A 37-Yr Period Of Land Use And Climate Change, Scott R. Abella, Ross J. Guida, Chris L. Roberts, Carrie M. Norman, James S. Holland

Life Sciences Faculty Research

Understanding long‐term changes in ecological communities during global change is a priority for 21st‐century ecology. Deserts, already at climatic extremes, are of unique interest because they are projected to be ecosystems most responsive to global change. Within a 500‐km2 landscape in the Mojave Desert, USA, we measured perennial plant communities at 100 sites three times (1979, 2008, and 2016) during 37 yr to evaluate six hypotheses of community change. These hypotheses encompassed shifts in community measures (e.g., diversity, cover) and species elevational distributions, biotic homogenization, disproportionately large change at the highest elevations, relationships between turnover and species’ responses to disturbance …


Heterogeneity In Surface Sensing Suggests A Division Of Labor In Pseudomonas Aeruginosa Populations, Catherine R. Armbuster, Calvin K. Lee, Jessica Parker-Gilham, Jaime De Anda, Aiguo Xia, Kun Zhao, Keiji Murakami, Boo Shan Tseng, Lucas R. Hoffman, Fan Jin, Caroline S. Harwood, Gerard Cl Wong, Matthew R. Parsek Jun 2019

Heterogeneity In Surface Sensing Suggests A Division Of Labor In Pseudomonas Aeruginosa Populations, Catherine R. Armbuster, Calvin K. Lee, Jessica Parker-Gilham, Jaime De Anda, Aiguo Xia, Kun Zhao, Keiji Murakami, Boo Shan Tseng, Lucas R. Hoffman, Fan Jin, Caroline S. Harwood, Gerard Cl Wong, Matthew R. Parsek

Life Sciences Faculty Research

The second messenger signaling molecule cyclic diguanylate monophosphate (c-di-GMP) drives the transition between planktonic and biofilm growth in many bacterial species. Pseudomonas aeruginosa has two surface sensing systems that produce c-di-GMP in response to surface adherence. Current thinking in the field is that once cells attach to a surface, they uniformly respond by producing c-di-GMP. Here, we describe how the Wsp system generates heterogeneity in surface sensing, resulting in two physiologically distinct subpopulations of cells. One subpopulation has elevated c-di-GMP and produces biofilm matrix, serving as the founders of initial microcolonies. The other subpopulation has low c-di-GMP and engages in …


Muscular Apoptosis But Not Oxidative Stress Increases With Old Age In A Long-Lived Diver, The Weddell Seal, Kaitlin N. Allen, Jose Pablo Vazquez-Medina, John M. Lawler, Jo-Ann E. Mellish, Markus Horning, Allyson G. Hindle Jun 2019

Muscular Apoptosis But Not Oxidative Stress Increases With Old Age In A Long-Lived Diver, The Weddell Seal, Kaitlin N. Allen, Jose Pablo Vazquez-Medina, John M. Lawler, Jo-Ann E. Mellish, Markus Horning, Allyson G. Hindle

Life Sciences Faculty Research

Seals experience repeated bouts of ischemia–reperfusion while diving, potentially exposing their tissues to increased oxidant generation and thus oxidative damage and accelerated aging. We contrasted markers of oxidative damage with antioxidant profiles across age and sex for propulsive (longissismus dorsi) and maneuvering (pectoralis) muscles of Weddell seals to determine whether previously observed morphological senescence is associated with oxidative stress. In longissismus dorsi, old (age 17–26 years) seals exhibited a nearly 2-fold increase in apoptosis over young (age 9–16 years) seals. There was no evidence of age-associated changes in lipid peroxidation or enzymatic antioxidant profiles. In pectoralis, 4-hydroxynonenal-Lys (4-HNE-Lys) levels increased …


Ecological Effects Of Fear: How Spatiotemporal Heterogeneity In Predation Risk Influences Mule Deer Access To Forage In A Sky‐Island System, Christopher Lowrey, Kathleen M. Longshore, David M. Choate, Jyoteshwar R. Nagol, Joseph Sexton, Daniel Thompson Jun 2019

Ecological Effects Of Fear: How Spatiotemporal Heterogeneity In Predation Risk Influences Mule Deer Access To Forage In A Sky‐Island System, Christopher Lowrey, Kathleen M. Longshore, David M. Choate, Jyoteshwar R. Nagol, Joseph Sexton, Daniel Thompson

Life Sciences Faculty Research

Forage availability and predation risk interact to affect habitat use of ungulates across many biomes. Within sky‐island habitats of the Mojave Desert, increased availability of diverse forage and cover may provide ungulates with unique opportunities to extend nutrient uptake and/or to mitigate predation risk. We addressed whether habitat use and foraging patterns of female mule deer (Odocoileus hemionus) responded to normalized difference vegetation index (NDVI), NDVI rate of change (green‐up), or the occurrence of cougars (Puma concolor). Female mule deer used available green‐up primarily in spring, although growing vegetation was available during other seasons. Mule deer and cougar shared similar …


Hawaiian Picture‐Winged Drosophila Exhibit Adaptive Population Divergence Along A Narrow Climatic Gradient On Hawaii Island, Jon Eldon, M. Renee Bellinger, Donald K. Price Feb 2019

Hawaiian Picture‐Winged Drosophila Exhibit Adaptive Population Divergence Along A Narrow Climatic Gradient On Hawaii Island, Jon Eldon, M. Renee Bellinger, Donald K. Price

Life Sciences Faculty Research

1. Anthropogenic influences on global processes and climatic conditions are increasingly affecting ecosystems throughout the world. 2. Hawaii Island’s native ecosystems are well studied and local long‐term climatic trends well documented, making these ecosystems ideal for evaluating how native taxa may respond to a warming environment. 3.This study documents adaptive divergence of populations of a Hawaiian picture‐winged Drosophila, D. sproati, that are separated by only 7 km and 365 m in elevation. 4.Representative laboratory populations show divergent behavioral and physiological responses to an experimental low‐intensity increase in ambient temperature during maturation. The significant interaction of source population by temperature treatment …


Cougar Dispersal And Natal Homing In A Desert Environment, David M. Choate, Kathleen M. Longshore, Daniel B. Thompson Aug 2018

Cougar Dispersal And Natal Homing In A Desert Environment, David M. Choate, Kathleen M. Longshore, Daniel B. Thompson

Life Sciences Faculty Research

We present a review of cougar dispersal literature and the first evidence of natural (i.e., unmanipulated) homing behavior by a dispersing male cougar (Puma concolor) that sustained severe injuries crossing the northern Mojave Desert. Based on Global Positioning System and ground tracking data, the male traveled a total distance of 981.1 km at 5.03 km/d, including 170.31 km from the Desert National Wildlife Refuge to the northwestern Grand Canyon, where he sustained severe injuries. The interkill interval increased from 7.1 ± 2.7 d while he was in his natal range to 17.5 ± 4.9 d during dispersal. While homing, the …


Genomic Inference Of The Metabolism And Evolution Of The Archaeal Phylum Aigarchaeota, Zheng-Shuang Hua, Yan-Ni Qu, Qiyun Zhu, En-Min Zhou, Yan-Ling Qi, Yi-Rui Yin, Yang-Zhi Rao, Ye Tian, Yu-Xian Li, Lan Liu, Cindy J. Castelle, Brian P. Hedlund, Wen-Sheng Shu, Rob Knight, Wen-Jun Li Jul 2018

Genomic Inference Of The Metabolism And Evolution Of The Archaeal Phylum Aigarchaeota, Zheng-Shuang Hua, Yan-Ni Qu, Qiyun Zhu, En-Min Zhou, Yan-Ling Qi, Yi-Rui Yin, Yang-Zhi Rao, Ye Tian, Yu-Xian Li, Lan Liu, Cindy J. Castelle, Brian P. Hedlund, Wen-Sheng Shu, Rob Knight, Wen-Jun Li

Life Sciences Faculty Research

Microbes of the phylum Aigarchaeota are widely distributed in geothermal environments, but their physiological and ecological roles are poorly understood. Here we analyze six Aigarchaeota metagenomic bins from two circumneutral hot springs in Tengchong, China, to reveal that they are either strict or facultative anaerobes, and most are chemolithotrophs that can perform sulfide oxidation. Applying comparative genomics to the Thaumarchaeota and Aigarchaeota, we find that they both originated from thermal habitats, sharing 1154 genes with their common ancestor. Horizontal gene transfer played a crucial role in shaping genetic diversity of Aigarchaeota and led to functional partitioning and ecological divergence among …


Status And Management Of Non-Native Plant Invasion In Three Of The Largest National Parks In The United States, Scott R. Abella, Nicholas A. Fisichelli, Sarah M. Schmid, Teague M. Embrey, Debra Hughson, Jane Cipra Jun 2016

Status And Management Of Non-Native Plant Invasion In Three Of The Largest National Parks In The United States, Scott R. Abella, Nicholas A. Fisichelli, Sarah M. Schmid, Teague M. Embrey, Debra Hughson, Jane Cipra

Life Sciences Faculty Research

Globally, invasion by non-native plants threatens resources that nature reserves are designated to protect. We assessed the status of non-native plant invasion on 1,662, 0.1-ha plots in Death Valley National Park, Mojave National Preserve, and Lake Mead National Recreation Area. These parks comprise 2.5 million ha, 23% of the national park land in the contiguous USA. At least one non-native species inhabited 82% of plots. Thirty-one percent of plots contained one non-native species, 30% two, 17% three, and 4% four to ten non-native species. Red brome (Bromus rubens), an ‘ecosystem engineer’ that alters fire regimes, was most widespread, …


Rapidly Restoring Biological Soil Crusts And Ecosystem Functions In A Severely Disturbed Desert Ecosystem, Lindsay P. Chiquoine, Scott R. Abella, Matthew A. Bowker Jun 2016

Rapidly Restoring Biological Soil Crusts And Ecosystem Functions In A Severely Disturbed Desert Ecosystem, Lindsay P. Chiquoine, Scott R. Abella, Matthew A. Bowker

Life Sciences Faculty Research

Restoring biological soil crusts (biocrusts) in degraded drylands can contribute to recovery of ecosystem functions that have global implications, including erosion resistance and nutrient cycling. To examine techniques for restoring biocrusts, we conducted a replicated, factorial experiment on recently abandoned road surfaces by applying biocrust inoculation (salvaged and stored dry for two years), salvaged topsoil, an abiotic soil amendment (wood shavings), and planting of a dominant perennial shrub (Ambrosia dumosa). Eighteen months after treatments, we measured biocrust abundance and species composition, soil chlorophyll a content and fertility, and soil resistance to erosion. Biocrust addition significantly accelerated biocrust recovery on disturbed …


Impacts And Management Of Hemlock Woolly Adelgid In National Parks Of The Eastern United States, Scott R. Abella Jan 2014

Impacts And Management Of Hemlock Woolly Adelgid In National Parks Of The Eastern United States, Scott R. Abella

Life Sciences Faculty Research

No abstract provided.


How Well Do U.S. Forest Service Terrestrial Ecosystem Surveys Correspond With Measured Vegetation Properties?, Scott R. Abella Jul 2011

How Well Do U.S. Forest Service Terrestrial Ecosystem Surveys Correspond With Measured Vegetation Properties?, Scott R. Abella

Life Sciences Faculty Research

No abstract provided.


Consequences Of More Extreme Precipitation Regimes For Terrestrial Ecosystems, S. D. Smith, C. Beier, Aimee T. Classen, Melinda D. Smith, Jana L. Heisler, S. W. Leavitt, Alan K. Knapp, D. Briske, Y. Luo, M. Reichstein, J. E. Bell, Philip A. Fay, R. Sherry, Benjamin Smith Oct 2008

Consequences Of More Extreme Precipitation Regimes For Terrestrial Ecosystems, S. D. Smith, C. Beier, Aimee T. Classen, Melinda D. Smith, Jana L. Heisler, S. W. Leavitt, Alan K. Knapp, D. Briske, Y. Luo, M. Reichstein, J. E. Bell, Philip A. Fay, R. Sherry, Benjamin Smith

Life Sciences Faculty Research

Amplification of the hydrological cycle as a consequence of global warming is forecast to lead to more extreme intra-annual precipitation regimes characterized by larger rainfall events and longer intervals between events. We present a conceptual framework, based on past investigations and ecological theory, for predicting the consequences of this underappreciated aspect of climate change. We consider a broad range of terrestrial ecosystems that vary in their overall water balance. More extreme rainfall regimes are expected to increase the duration and severity of soil water stress in mesic ecosystems as intervals between rainfall events increase. In contrast, xeric ecosystems may exhibit …


Monitoring Temporal Change In Riparian Vegetation Of Great Basin National Park, E. A. Beever, D. A. Pyke, J. C. Chambers, F. Landau, S. D. Smith, K. Murray Jan 2005

Monitoring Temporal Change In Riparian Vegetation Of Great Basin National Park, E. A. Beever, D. A. Pyke, J. C. Chambers, F. Landau, S. D. Smith, K. Murray

Life Sciences Faculty Research

Disturbance in riparian areas of semiarid ecosystems involves complex interactions of pulsed hydrologic flows, herbivory, fire, climatic effects, and anthropogenic influences. We resampled riparian vegetation within ten 10-m × 100-m plots that were initially sampled in 1992 in 4 watersheds of the Snake Range, east central Nevada. Our finding of significantly lower coverage of grasses, forbs, and shrubs within plots in 2001 compared with 1992 was not consistent with the management decision to remove livestock grazing from the watersheds in 1999. Change over time in cover of life-forms or bare ground was not predicted by scat counts within plots in …


Microbial Endemism And Biogeography, Brian P. Hedlund, James T. Staley Jan 2004

Microbial Endemism And Biogeography, Brian P. Hedlund, James T. Staley

Life Sciences Faculty Research

The topic of microbial biogeography is almost 100 years old, however, when confronted with questions about the existence and extent of endemism in the microbial world, many microbiologists respond with opinions and theoretical arguments rather than examples of well-conducted studies. We begin this chapter with an overview of this debate as it applies to free-living prokayotes in part because there are relatively few good microbial biogeography studies. Furthermore, the arguments help to frame microbial biogeography in the larger context of biodiversity in that if endemism is common, then many more species exist.


Arbuscular Mycorrhizae Of Mojave Desert Plants, J. H. Titus, P. J. Titus, R. S. Nowak, S. D. Smith Jan 2002

Arbuscular Mycorrhizae Of Mojave Desert Plants, J. H. Titus, P. J. Titus, R. S. Nowak, S. D. Smith

Life Sciences Faculty Research

Roots of 15 Mojave Desert plant species were assessed for arbuscular mycorrhizal (AM) colonization in spring and autumn 1999. Another 19 species were assessed in autumn only. Perennial species were AM colonized, whereas annual species contained very low levels of AM hyphae or were nonmycorrhizal. The nonnative tree Tamarix ramosissima was also nonmycorrhizal. Levels of hyphae changed over the season in 2 species, arbuscle levels increased in 1 species, and vesicles decreased in 7 species. Mycorrhizal inoculum potential (MIP) was assessed in the soils associated with spring-collected plants. All soils were found to contain MIP. MIP values were not correlated …


Bowen Ratio Estimates Of Evapotranspiration For Stands On The Virgin River In Southern Nevada, Dale A. Devitt, A. Sala, S. D. Smith, J. Cleverly, L. K. Shaulis, R. Hammett Jan 1998

Bowen Ratio Estimates Of Evapotranspiration For Stands On The Virgin River In Southern Nevada, Dale A. Devitt, A. Sala, S. D. Smith, J. Cleverly, L. K. Shaulis, R. Hammett

Life Sciences Faculty Research

A Bowen ratio energy balance was conducted over a Tamarix ramosissima (saltcedar) stand growing in a riparian corridor along the Virgin River in southern Nevada. Measurements in two separate years were compared and contrasted on the basis of changes in growing conditions. In 1994, a drought year, record high temperatures, dry winds, and a falling water table caused partial wilt of outer smaller twigs in the canopy of many trees in the stand around the Bowen tower. Subsequently, evapotranspiration (ET) estimates declined dramatically over a 60‐day period (11 mm d−1 tod−1). In 1995, the Virgin River at the Bowen tower …


Evapotranspiration From A Saltcedar-Dominated Desert Floodplain: A Scaling Approach, S. D. Smith, A. M. Sala, Dale A. Devitt Jan 1996

Evapotranspiration From A Saltcedar-Dominated Desert Floodplain: A Scaling Approach, S. D. Smith, A. M. Sala, Dale A. Devitt

Life Sciences Faculty Research

The purpose of this study was to investigate evapotranspiration (ET) from a variety of scales (leaf to landscape) in saltcedar-dominated floodplain vegetation along the lower Virgin River of southern Nevada. Leaf-level gas exchange indicated that saltcedar exhibits similar stomatal conductance as the sympatric phreatophytes arrowweed, mesquite, and willow. However, sap flow in saltcedar was higher per unit sapwood area than the other species, suggesting that it maintains higher leaf area per unit sapwood area. At the stand level, saltcedar ET was found to exceed potential ET early in the summer when soils were moist and the water table was near …


Structure Of Woody Riparian Vegetation In Great Basin National Park, S. D. Smith, K. J. Murray, F. H. Landau, A. M. Sala Jan 1995

Structure Of Woody Riparian Vegetation In Great Basin National Park, S. D. Smith, K. J. Murray, F. H. Landau, A. M. Sala

Life Sciences Faculty Research

The community composition and population structure of the woody riparian vegetation in Great Basin National Park are described. Community analyses were accomplished by sampling 229 plots along an elevational gradient of 8 major stream systems in the Park. TWINSPAN analysis identified 4 primary species groups that were characterized by Populus tremuloides (aspen), Abies concolor (white fir), Rosa woodsii (Woods rose), and Populus angustifolia (narrowleaf cottonwood) as dominants, respectively. Detrended Correspondence Analysis (DECORANA) showed that the most important environmental factors associated with the distribution of species were elevation and slope, with flood-related physiographic factors having a secondary effect. Analysis of size-class …