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Biology Faculty Publications

2005

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Full-Text Articles in Life Sciences

Sal-Site: Integrating New And Existing Ambystomatid Salamander Research And Informational Resources, Jeramiah J. Smith, Srikrishna Putta, John A. Walker, D. Kevin Kump, Amy K. Samuels, James R. Monaghan, David W. Weisrock, Chuck Staben, S. Randal Voss Dec 2005

Sal-Site: Integrating New And Existing Ambystomatid Salamander Research And Informational Resources, Jeramiah J. Smith, Srikrishna Putta, John A. Walker, D. Kevin Kump, Amy K. Samuels, James R. Monaghan, David W. Weisrock, Chuck Staben, S. Randal Voss

Biology Faculty Publications

Salamanders of the genus Ambystoma are a unique model organism system because they enable natural history and biomedical research in the laboratory or field. We developed Sal-Site to integrate new and existing ambystomatid salamander research resources in support of this model system. Sal-Site hosts six important resources: 1) Salamander Genome Project: an information-based web-site describing progress in genome resource development, 2) Ambystoma EST Database: a database of manually edited and analyzed contigs assembled from ESTs that were collected from A. tigrinum tigrinum and A. mexicanum, 3) Ambystoma Gene Collection: a database containing full-length protein-coding sequences, 4) Ambystoma Map and Marker …


Seagrass–Pathogen Interactions: ‘Pseudo-Induction’ Of Turtlegrass Phenolics Near Wasting Disease Lesions, Latina Steele, Melanie Caldwell, Anne Boettcher, Tom Arnold Nov 2005

Seagrass–Pathogen Interactions: ‘Pseudo-Induction’ Of Turtlegrass Phenolics Near Wasting Disease Lesions, Latina Steele, Melanie Caldwell, Anne Boettcher, Tom Arnold

Biology Faculty Publications

Marine protists of the genus Labyrinthula cause the seagrass wasting disease, which is associated with regional die-offs of eelgrass Zostera marina and also infects turtlegrass Thalassia testudinum . The ability of seagrasses to resist pathogen attack is determined by multiple factors, which are poorly understood. One factor hypothesized to influence seagrass disease resistance is the presence of (poly)phenolic natural products such as caffeic acid, which inhibits the growth of L. zosterae in in vitro laboratory bioassays. This hypothesis has been supported by reports of pathogen-induced phenolic accumulations in eelgrass Z. marina. To test the response of T. testudinum to …


Empirical Analysis Of The Str Profiles Resulting From Conceptual Mixtures, David R. Paoletti, Travis E. Doom, Carissa M. Krane, Michael L. Raymer, Dan E. Krane Nov 2005

Empirical Analysis Of The Str Profiles Resulting From Conceptual Mixtures, David R. Paoletti, Travis E. Doom, Carissa M. Krane, Michael L. Raymer, Dan E. Krane

Biology Faculty Publications

Samples containing DNA from two or more individuals can be difficult to interpret. Even ascertaining the number of contributors can be challenging and associated uncertainties can have dramatic effects on the interpretation of testing results. Using an FBI genotypes dataset, containing complete genotype information from the 13 Combined DNA Index System (CODIS) loci for 959 individuals, all possible mixtures of three individuals were exhaustively and empirically computed. Allele sharing between pairs of individuals in the original dataset, a randomized dataset and datasets of generated cousins and siblings was evaluated as were the number of loci that were necessary to reliably …


Callose (Β-1,3 Glucan) Is Essential For Arabidopsis Pollen Wall Patterning, But Not Tube Growth, Rob Swanson Oct 2005

Callose (Β-1,3 Glucan) Is Essential For Arabidopsis Pollen Wall Patterning, But Not Tube Growth, Rob Swanson

Biology Faculty Publications

Background: Callose (β-1,3 glucan) separates developing pollen grains, preventing their underlying walls (exine) from fusing. The pollen tubes that transport sperm to female gametes also contain callose, both in their walls as well as in the plugs that segment growing tubes. Mutations in CalS5, one of several Arabidopsis β-1,3 glucan synthases, were previously shown to disrupt callose formation around developing microspores, causing aberrations in exine patterning, degeneration of developing microspores, and pollen sterility. Results: Here, we describe three additional cals5 alleles that similarly alter exine patterns, but instead produce fertile pollen. Moreover, one of these alleles (cals5-3) resulted in the …


Redescripción De La Morfología Larval Externa De Dos Especies Del Grupo De Leptodactylus Fuscus (Anura, Leptodactylidae), José A. Langone, Rafael O. De Sá Oct 2005

Redescripción De La Morfología Larval Externa De Dos Especies Del Grupo De Leptodactylus Fuscus (Anura, Leptodactylidae), José A. Langone, Rafael O. De Sá

Biology Faculty Publications

Re-description of the larval external morphology of two species of the Leptodactylus fuscus group (Anura, Leptodactylidae). The larvae of Leptodactylus gracilis (D’Orbigny y Bibron, 1840) and L. mystacinus Bumeister, 1861 are re-described and compared with previous descriptions noting intraspecific variation in oral disc characteristics (arrangement of papillae and rows of cornified teeth). The external morphological analysis of larvae of the Leptodactylus fuscus group suggest that the lack of comparable descriptions among species, as well as the lack of analyses of their intraspecific variation, limits the use of larval characteristics for diagnostic purposes.


A Phylogenetic Analysis Of Vanzolinius Heyer, 1974 (Amphibia, Anura, Leptodactylidae): Taxonomic And Life History Implications, Rafael O. De Sá, W. Ronald Heyer, Arley Camargo Oct 2005

A Phylogenetic Analysis Of Vanzolinius Heyer, 1974 (Amphibia, Anura, Leptodactylidae): Taxonomic And Life History Implications, Rafael O. De Sá, W. Ronald Heyer, Arley Camargo

Biology Faculty Publications

The validity of the monotypic leptodactylid frog genus Vanzolinius Heyer, 1974 has been questioned recently. We explore the relationship of Vanzolinius discodactylus within the cluster of closely related genera Adenomera, Leptodacylus, and Lithodytes with both morphological and molecular data sets. Morphological and combined morphological and molecular data were analyzed using maximum parsimony; molecular data sets were analyzed with maximum likelihood methods. The resultant relationships are unambiguous in Vanzolinius being imbedded within Leptodactylus. In order to maintain Leptodactylus as a monophyletic genus, Vanzolinius is placed in the synonymy of Leptodactylus Fitzinger, 1826. The implications of relationships analyzed in …


Atypical Pkciota Contributes To Poor Prognosis Through Loss Of Apical-Basal Polarity And Cyclin E Overexpression In Ovarian Cancer, Astrid M. Eder, Xiaomei Sui, Daniel G. Rosen, Laura K. Nolden, Kwai Wa Cheng, John P. Lahad, Madhuri Kango-Singh, Karen H. Lu, Carla L. Warneke, Edward N. Atkinson, Isabelle Bedrosian, Khandan Keyomarsi, Wen-Lin Kuo, Joe W. Gray, Jerry C. P. Yin, Jinsong Liu, Georg Halder, Gordon B. Mills Aug 2005

Atypical Pkciota Contributes To Poor Prognosis Through Loss Of Apical-Basal Polarity And Cyclin E Overexpression In Ovarian Cancer, Astrid M. Eder, Xiaomei Sui, Daniel G. Rosen, Laura K. Nolden, Kwai Wa Cheng, John P. Lahad, Madhuri Kango-Singh, Karen H. Lu, Carla L. Warneke, Edward N. Atkinson, Isabelle Bedrosian, Khandan Keyomarsi, Wen-Lin Kuo, Joe W. Gray, Jerry C. P. Yin, Jinsong Liu, Georg Halder, Gordon B. Mills

Biology Faculty Publications

We show that atypical PKCι, which plays a critical role in the establishment and maintenance of epithelial cell polarity, is genomically amplified and overexpressed in serous epithelial ovarian cancers. Furthermore, PKCι protein is markedly increased or mislocalized in all serous ovarian cancers. An increased PKCι DNA copy number is associated with decreased progression-free survival in serous epithelial ovarian cancers. In a Drosophila in vivo epithelial tissue model, overexpression of persistently active atypical PKC results in defects in apical-basal polarity, increased Cyclin E protein expression, and increased proliferation. Similar to the Drosophila model, increased PKCι proteins levels are associated with …


Group 13 Hox Proteins Interact With The Mh2 Domain Of R-Smads And Modulate Smad Transcriptional Activation Functions Independent Of Hox Dna Binding Capability, Thomas M. Williams, Melissa E. Williams, Joanne H. Heaton, Thomas D. Gelehrter, Jeffrey W. Innis Aug 2005

Group 13 Hox Proteins Interact With The Mh2 Domain Of R-Smads And Modulate Smad Transcriptional Activation Functions Independent Of Hox Dna Binding Capability, Thomas M. Williams, Melissa E. Williams, Joanne H. Heaton, Thomas D. Gelehrter, Jeffrey W. Innis

Biology Faculty Publications

Interactions with co-factors provide a means by which HOX proteins exert specificity. To identify candidate protein interactors of HOXA13, we created and screened an E11.5–E12.5, distal limb bud yeast two-hybrid prey library. Among the interactors, we isolated the BMP-signaling effector Smad5, which interacted with the paralogous HOXD13 but not with HOXA11 or HOXA9, revealing unique interaction capabilities of the AbdB-like HOX proteins. Using deletion mutants, we determined that the MH2 domain of Smad5 is necessary for HOXA13 interaction.

This is the first report demonstrating an interaction between HOX proteins and the MH2 domain of Smad proteins. HOXA13 and HOXD13 …


"Sibling Species, Advertisement Calls, And Reproductive Isolation In Frogs Of The Leptodactylus Pentadactylus Species Cluster (Amphibia, Leptodactylidae), W. Ronald Heyer, Rafael O. De Sá, A. Rettig Aug 2005

"Sibling Species, Advertisement Calls, And Reproductive Isolation In Frogs Of The Leptodactylus Pentadactylus Species Cluster (Amphibia, Leptodactylidae), W. Ronald Heyer, Rafael O. De Sá, A. Rettig

Biology Faculty Publications

A recent re-evaluation of morphological and advertisement call variation in the large species of frogs of the Leptodactylus pentadactylus cluster discovered more examples of sibling species as defined by Ernst Mayr in his influential book Animal Species and Evolution. All previously documented instances of sibling species in frogs demonstrated advertisement call differentiation consistent with the calls serving as pre-mating isolating mechanisms. However, we find one instance of two species with nondistinguishable adult morphologies as well as nondistinguishable advertisement calls. Presumably, the new instances of sibling species reflect retention of ancestral adult morphologies and advertisement calls. Larval and habitat differentiation appear …


First Confirmed Breeding Of The Rock Wren In Minnesota, Philip C. Chu Jul 2005

First Confirmed Breeding Of The Rock Wren In Minnesota, Philip C. Chu

Biology Faculty Publications

No abstract provided.


Predator- And Competitor-Induced Plasticity: How Changes In Foraging Morphology Affect Phenotypic Trade-Offs, Rick A. Relyea, Josh R. Auld Jul 2005

Predator- And Competitor-Induced Plasticity: How Changes In Foraging Morphology Affect Phenotypic Trade-Offs, Rick A. Relyea, Josh R. Auld

Biology Faculty Publications

No abstract provided.


Seasonal Changes In Composition Of Lipid Stores In Migratory Birds: Causes And Consequences, Barbara J. Pierce, Scott R. Mcwilliams May 2005

Seasonal Changes In Composition Of Lipid Stores In Migratory Birds: Causes And Consequences, Barbara J. Pierce, Scott R. Mcwilliams

Biology Faculty Publications

It is well established that birds use fat stores to primarily fuel migration; however, few studies have focused on the causes and consequences of observed seasonal changes in fatty acid composition of fat stores in birds. We propose and test two hypotheses that address the causes of these seasonal changes in composition of fat stores: (1) diet composition determines fatty acid composition of fat stores, and (2) birds selectively metabolize and store certain fatty acids during migration in lieu of changing their diet. When we offered Red-eyed Vireos (Vireo olivaceous) choices between diets that differed only in fatty acid composition, …


Myod Targets Chromatin Remodeling Complexes To The Myogenin Locus Prior To Forming A Stable Dna-Bound Complex, Ivana L. De La Serna, Yasuyuki Ohkawa, Charlotte A. Berkes, Donald A. Bergstrom, Caroline S. Dacwag, Stephen J. Tapscott, Anthony N. Imbalzano May 2005

Myod Targets Chromatin Remodeling Complexes To The Myogenin Locus Prior To Forming A Stable Dna-Bound Complex, Ivana L. De La Serna, Yasuyuki Ohkawa, Charlotte A. Berkes, Donald A. Bergstrom, Caroline S. Dacwag, Stephen J. Tapscott, Anthony N. Imbalzano

Biology Faculty Publications

The activation of muscle-specific gene expression requires the coordinated action of muscle regulatory proteins and chromatin-remodeling enzymes. Microarray analysis performed in the presence or absence of a dominant-negative BRG1 ATPase demonstrated that approximately one-third of MyoD-induced genes were highly dependent on SWI/SNF enzymes. To understand the mechanism of activation, we performed chromatin immunoprecipitations analyzing the myogenin promoter. We found that H4 hyperacetylation preceded Brg1 binding in a MyoD-dependent manner but that MyoD binding occurred subsequent to H4 modification and Brg1 interaction. In the absence of functional SWI/SNF enzymes, muscle regulatory proteins did not bind to the myogenin promoter, thereby providing …


Assessment Of Student Skills For Critiquing Published Primary Scientific Literature: Using A Primary Trait Analysis Scale, Manuel F. Varela, Marvin M.F. Lutnesky, Marcy P. Osgood May 2005

Assessment Of Student Skills For Critiquing Published Primary Scientific Literature: Using A Primary Trait Analysis Scale, Manuel F. Varela, Marvin M.F. Lutnesky, Marcy P. Osgood

Biology Faculty Publications

Instructor evaluation of progressive student skills in the analysis of primary literature is critical for the development of these skills in young scientists. Students in a senior or graduate-level one-semester course in Immunology at a Masters-level comprehensive university were assessed for abilities (primary traits) to recognize and evaluate the following elements of a scientific paper: Hypothesis and Rationale, Significance, Methods, Results, Critical Thinking and Analysis, and Conclusions. We tested the hypotheses that average recognition scores vary among elements and that scores change with time differently by trait. Recognition scores (scaled 1 to 5), and differences in scores were analyzed using …


The Biology Of Canadian Weeds. 131. Polygonum Aviculare L., Mihai Costea, François J. Tardif Apr 2005

The Biology Of Canadian Weeds. 131. Polygonum Aviculare L., Mihai Costea, François J. Tardif

Biology Faculty Publications

A review and assessment of biological information as well as personal data are provided for Polygonum aviculare in Canada. The species has been revised taxonomically and the six subspecies that occur in Canada are presented. Three of the subspecies, P. aviculare subsp. aviculare, P. aviculare subsp. neglectum and P. aviculare subsp. depressum are weeds introduced to Canada from Europe. A fourth subspecies, P. aviculare subsp. buxiforme is apparently native to North America. The geographical distribution of the latter four subspecies is very wide. Plants exhibit a high phenotypic plasticity and genetic variability, and they easily adapt to a multitude …


Investigations Of Migratory Bull Trout (Salvelinus Confluentus) In Relation To Fish Passage At Albeni Falls Dam, Allan T. Scholz, Holly J. Mclellan, David R. Geist, Richard S. Brown, United States Department Of The Army Corps Of Engineers, Seattle District, Eastern Washington University Mar 2005

Investigations Of Migratory Bull Trout (Salvelinus Confluentus) In Relation To Fish Passage At Albeni Falls Dam, Allan T. Scholz, Holly J. Mclellan, David R. Geist, Richard S. Brown, United States Department Of The Army Corps Of Engineers, Seattle District, Eastern Washington University

Biology Faculty Publications

Final report prepared for the United States Department of the Army Corps of Engineers, Seattle District. Contract No. DACW68-02-D-001


Judicious Use Of Multiple Hypothesis Tests, Paul J. Roback, Robert A. Askins Feb 2005

Judicious Use Of Multiple Hypothesis Tests, Paul J. Roback, Robert A. Askins

Biology Faculty Publications

When analyzing a table of statistical results, one must first decide whether adjustment of significance levels is appropriate. If the main goal is hypothesis generation or initial screening for potential conservation problems, then it may be appropriate to use the standard comparisonwise significance level to avoid Type 2 errors (not detecting real differences or trends). If, however, the main goal is rigorous testing of a hypothesis, then an adjustment for multiple tests is needed. To control the familywise Type 1 error rate (the probability of rejecting at least one true null hypothesis), sequential modifications of the standard Bonferroni Method, such …


Bloodroot Pollination: Bet-Hedging In Uncertain Times, W. John Hayden Feb 2005

Bloodroot Pollination: Bet-Hedging In Uncertain Times, W. John Hayden

Biology Faculty Publications

“Hurry up and wait.” The phrase that epitomizes life in the military or any other large, bureaucratic, organization, applies surprisingly well to bloodroot and similar ephemeral wildflowers. Each year these plants race to flower as early as possible to assure sufficient time for fruits to ripen and seeds to mature while sunshine is abundant at the forest floor, for all too soon the forest floor will be draped in shadows cast by the trees’ leafy canopy. Ephemerals do everything quickly: sprout, grow, flower, disperse seeds, and re-enter dormancy. But flowering in very early spring can be risky. Some days will …


Biphasic Functions Of The Kinase-Defective Ephb6 Receptor In Cell Adhesion And Migration, Hiroshi Matsuoka, Hiroya Obama, Meghan Kelly, Toshimitsu Matsui, Masaru Nakamoto Jan 2005

Biphasic Functions Of The Kinase-Defective Ephb6 Receptor In Cell Adhesion And Migration, Hiroshi Matsuoka, Hiroya Obama, Meghan Kelly, Toshimitsu Matsui, Masaru Nakamoto

Biology Faculty Publications

EphB6 is a unique member in the Eph family of receptor tyrosine kinases in that its kinase domain contains several alterations in conserved amino acids and is catalytically inactive. Although EphB6 is expressed both in a variety of embryonic and adult tissues, biological functions of this receptor are largely unknown. In the present study, we examined the function of EphB6 in cell adhesion and migration. We demonstrated that EphB6 exerted biphasic effects in response to different concentrations of the ephrin-B2 ligand; EphB6 promoted cell adhesion and migration when stimulated with low concentrations of ephrin-B2, whereas it induced repulsion and inhibited …


Mutations Affecting Cleavage At The P10-Capsid Protease Cleavage Site Block Rous Sarcoma Virus Replication, Marcy L. Vana, Aiping Chen, Peter Boross, Irene Weber, Dalbinder Colman, Eric Barklis, Jonathan Leis Jan 2005

Mutations Affecting Cleavage At The P10-Capsid Protease Cleavage Site Block Rous Sarcoma Virus Replication, Marcy L. Vana, Aiping Chen, Peter Boross, Irene Weber, Dalbinder Colman, Eric Barklis, Jonathan Leis

Biology Faculty Publications

A series of amino acid substitutions (M239F, M239G, P240F, V241G) were placed in the p10-CA protease cleavage site (VVAM*PVVI) to change the rate of cleavage of the junction. The effects of these substitutions on p10-CA cleavage by RSV PR were confirmed by measuring the kinetics of cleavage of model peptide substrates containing the wild type and mutant p10-CA sites. The effects of these substitutions on processing of the Gag polyprotein were determined by labeling Gag transfected COS-1 cells with 35S-Met and -Cys, and immunoprecipitation of Gag and its cleavage products from the media and lysate fractions. All substitutions except M239F …


Two Purified Domains Of Telomerase Reverse Transcriptase Reconstitute Sequence-Specific Interactions With Rna, C. M. O'Connor, Cary K. Lai, Kathleen Collins Jan 2005

Two Purified Domains Of Telomerase Reverse Transcriptase Reconstitute Sequence-Specific Interactions With Rna, C. M. O'Connor, Cary K. Lai, Kathleen Collins

Biology Faculty Publications

Telomerase reverse transcriptase (TERT) and telomerase RNA (TER) function together to create a uniquely specialized polymerase. Here we have described for the first time domains of bacterially expressed Tetrahymena TERT that interacted directly with TER in the absence of assembly chaperones. We used quantitative binding assays to define TER sequence requirements for recognition by the high affinity RNA binding domain and an independent N-terminal RNA interaction domain. The TERT RNA binding domain and N-terminal RNA interaction domain had distinct, nonoverlapping requirements for TER sequence and structure that together accounted for all of the sites of TER contact inferred for full-length …


The Challenge Of Environmental Protection, Jennifer Mattei Jan 2005

The Challenge Of Environmental Protection, Jennifer Mattei

Biology Faculty Publications

Connecticut is in the midst of a demographic transition to a period of lower population growth. These demographic changes will help check the pressures exerted on the state's natural resources by population growth. Water, air, soil, energy sources, food, fisheries, forests, and biodiversity are common pool resources upon which we depend in ways that transcend political boundaries. Those governing Connecticut should help turn the state into a model of how to manage natural resources by halting forest fragmentation, reducing pollution, and promoting environmental science education.


Effect Of Dietary Fatty Acid Composition On Depot Fat And Exercise Performance In A Migrating Songbird, The Red-Eyed Vireo, Barbara J. Pierce, Scott R. Mcwilliams, Timothy P. O'Connor, Allen R. Place, Christopher G. Guglielmo Jan 2005

Effect Of Dietary Fatty Acid Composition On Depot Fat And Exercise Performance In A Migrating Songbird, The Red-Eyed Vireo, Barbara J. Pierce, Scott R. Mcwilliams, Timothy P. O'Connor, Allen R. Place, Christopher G. Guglielmo

Biology Faculty Publications

Most migrating birds accumulate lipid stores as their primary source of energy for fueling long distance flights. Lipid stores of birds during migration are composed of mostly unsaturated fatty acids; whether such a fatty acid composition enhances exercise performance of birds is unknown. We tested this hypothesis by measuring metabolic rate at rest and during intense exercise in two groups of red-eyed vireos, a long-distance migratory passerine, fed either a diet containing 82% unsaturated fat (82%U), or one containing 58% unsaturated fat (58%U). Vireos fed the 82%U diet had fat stores containing (77%) unsaturated fatty acids, whereas vireos fed the …


North American Watersnakes: A Natural History, Alan H. Savitzky Jan 2005

North American Watersnakes: A Natural History, Alan H. Savitzky

Biology Faculty Publications

No abstract provided.


Evidence For A General Species Time Arearelationship, P. B. Adler, Ethan P. White, W. K. Lauenroth, D. M. Kaufman, A. Rassweiler, J. A. Rusak Jan 2005

Evidence For A General Species Time Arearelationship, P. B. Adler, Ethan P. White, W. K. Lauenroth, D. M. Kaufman, A. Rassweiler, J. A. Rusak

Biology Faculty Publications

The species-area relationship (SAR) plays a central role in biodiversity research, and recent work has increased awareness of its temporal analog, the species-time relationship (STR). Here we provide evidence for a general species-time-area-relationship (STAR), in which species number is a function of the area and time span of sampling, as well as their interaction. For eight assemblages ranging from lake zooplankton to desert rodents, this model outperformed a sampling-based model and two simpler models in which area and time had independent effects. In every case the interaction term was negative, meaning that rates of species accumulation in space decreased with …


Plant Composition Of Mixed-Grass Prairie Of Cedar Point Biological Research Station, Keith County, Nebraska, David A. Mckenzie Jan 2005

Plant Composition Of Mixed-Grass Prairie Of Cedar Point Biological Research Station, Keith County, Nebraska, David A. Mckenzie

Biology Faculty Publications

This study involved a vegetation analysis of 15 permanent plots established on the short-grass and mixed grass prairie slopes at the Cedar Point Biological Station in Keith County, Nebraska. Ninety-nine species were found in the plots, including members of 75 genera and 31 families. Twenty-one were graminoids, 71 were forbs or succulents, 6 were shrubs and one was a tree. Bouteloua gracilis (19 % cover) and Carex filifolia (15 % cover) were the dominant graminoids at the site, while Yucca glauca (1% cover) and Artemisia frigida (1% cover) were the most frequent forbs. Comparisons of species richness by slope categories …


The Flood Pulse In A Semi-Arid Riparian Forest:Metabolic And Biogeochemical Responses To Inter-Flood Interval, H. M. Valett, Michelle A. Baker, J. A. Morrice, C. S. Crawford, M. C. Molles, C. N. Dahm, D. L. Moyer, J. R. Thibault Jan 2005

The Flood Pulse In A Semi-Arid Riparian Forest:Metabolic And Biogeochemical Responses To Inter-Flood Interval, H. M. Valett, Michelle A. Baker, J. A. Morrice, C. S. Crawford, M. C. Molles, C. N. Dahm, D. L. Moyer, J. R. Thibault

Biology Faculty Publications

Flood pulse inundation of riparian forests alters rates of nutrient retention and organic matter processing in the aquatic ecosystems formed in the forest interior. Along the Middle Rio Grande (New Mexico, USA), impoundment and levee construction have created riparian forests that differ in their inter-flood intervals (IFIs) because some floodplains are still regularly inundated by the flood pulse (i.e., connected), while other floodplains remain isolated from flooding (i.e., disconnected). This research investigates how ecosystem responses to the flood pulse relate to forest IFI by quantifying nutrient and organic matter dynamics in the Rio Grande floodplain during three years of experimental …


Body Size, Energy Use, And Community Structure Of Small Mammals, S.K. Morgan Ernest Jan 2005

Body Size, Energy Use, And Community Structure Of Small Mammals, S.K. Morgan Ernest

Biology Faculty Publications

Body size has long been hypothesized to play a major role in community structure and dynamics. Two general hypotheses exist for how resources are distributed among body sizes: (1) resources are equally available and uniformly utilized across body sizes and (2) resources are differentially available to organisms of different body sizes, resulting in a nonuniform or modal distribution. It has also been predicted that the distri-bution of body sizes of species in a community should reflect the underlying availability of resources, with the emergence of aggregations of species around specific body sizes. I examined the relationship between energy utilization, body …


Intra-Guild Compensation Regulatesspecies Richness In Desert Rodents, J. Goheen, Ethan P. White, S.K. Morgan Ernest, J. H. Brown Jan 2005

Intra-Guild Compensation Regulatesspecies Richness In Desert Rodents, J. Goheen, Ethan P. White, S.K. Morgan Ernest, J. H. Brown

Biology Faculty Publications

Evidence from numerous studies suggests that species richness is an emergent property of local communities. The maintenance of species richness, despite changes in species composition and environmental conditions, requires compensatory colonization and extinction events with species coming from a regional pool. Using long-term data from a rodent community in the Chihuahuan Desert, we use randomization methods to test the null hypothesis that changes in species richness occur randomly. We find that the dynamics of species richness differ significantly from a random process, and that these nonrandom dynamics occur largely within the most speciose guild. Finally, we propose a general framework …


Controls On Nitrogen Cycling In Terrestrial Ecosystems: A Synthetic Analysis Of Literature Data, M. S. Booth, E. Rastetter, John M. Stark Jan 2005

Controls On Nitrogen Cycling In Terrestrial Ecosystems: A Synthetic Analysis Of Literature Data, M. S. Booth, E. Rastetter, John M. Stark

Biology Faculty Publications

Isotope pool dilution studies are increasingly reported in the soils and ecology literature as a means of measuring gross rates of nitrogen (N) mineralization, nitrification, and inorganic N assimilation in soils. We assembled data on soil characteristics and gross rates from 100 studies conducted in forest, shrubland, grassland, and agricultural systems to answer the following questions: What factors appear to be the major drivers for production and consumption of inorganic N as measured by isotope dilution studies? Do rates or the relationships between drivers and rates differ among ecosystem types? Across a wide range of ecosystems, gross N mineralization is …