Weed Science Commons^™

Water Use And Water Tolerance In The Riparian Species American Sycamore (Plantanus Occidentalis L.) And How Its Physiology Compares To The Coexisting Black Willow (Salix Nigra Marshall), Eric Duncan

Dissertations, Theses and Capstone Projects (Full IR Collection)

This study set out to compare aspects of water use and tolerance to inundation and drought of two riparian tree species, Platanus occidentalis L. and Salix nigra Marshall. The main goal of the study was to better understand the two species and assess the suitability of P. occidentalis for use in riparian restoration. To accomplish this, potted individuals were subjected to treatments of drought, inundation, or control, under greenhouse conditions, and separately, in order to estimate water use in trees, season-long diurnal measurements of sap flux (using Granier type thermal dissipation probes) were determined in situ for trees growing in …

Local Filters Limit Species Diversity, But Species Pools Determine Composition, Tara K. Rajaniemi, Deborah E. Goldberg, Roy Turkington, Andrew R. Dyer

Faculty Publications

In a series of three experiments, we tested for effects of species pools, resource stress, and species interactions on four aspects of community structure: species richness, evenness, species composition, and functional group composition. We also examined whether the impacts of species interactions on the community varied with resource availability or species pool. Communities of sand dune annuals grew from seed bank samples collected from two sites in three different years, so that the species pool differed at two levels: the source site and the year of seed bank collection. Communities experienced one of three irrigation treatments and a range of …

Influence Of Microsite Disturbance On The Establishment Of Two Congeneric Invasive Thistles, Emily S.J. Rauschert, Katriona Shea

Biological, Geological, and Environmental Faculty Publications

The successful establishment of invasive species has been shown to depend on aspects of the invaded community, such as gap characteristics. Biotic resistance may be particularly critical for stopping invaders at early life history stages, but new species can often invade following disturbances, which may create microsites with very different characteristics than are usually present. We examine the response of two invasive thistle species, Carduus nutans L. and C. acanthoides L., to three different microsite characteristics: disturbance type, size, and water availability. The two species initially responded differently to the type of disturbance: C. acanthoides had higher emergence and survival …

Invasional Interference Due To Similar Inter- And Intraspecific Competition Between Invaders May Affect Management, Emily S.J. Rauschert, Katriona Shea

Biological, Geological, and Environmental Faculty Publications

As the number of biological invasions increases, the potential for invader– invader interactions also rises. The effect of multiple invaders can be superadditive (invasional meltdown), additive, or subadditive (invasional interference); which of these situations occurs has critical implications for prioritization of management efforts. Carduus nutans and C. acanthoides, two congeneric invasive weeds, have a striking, segregated distribution in central Pennsylvania, USA. Possible hypotheses for this pattern include invasion history and chance, direct competition, or negative interactions mediated by other species, such as shared pollinators. To explore the role of resource competition in generating this pattern, we conducted three related experiments …

Coexistence Patterns Of Two Invasive Thistle Species, Carduus Nutans And C. Acanthoides, At Three Spatial Scales, Emily S.J. Rauschert, Katriona Shea, Ottar N. Bjørnstad

Biological, Geological, and Environmental Faculty Publications

To better understand the competitive processes involved in invasion by congeners, we examine coexistence patterns of two invasive species, Carduus nutans and C. acanthoides, at three spatial scales. A roadside survey of 5 × 5 km blocks in a previously identified overlap zone provided information about the regional scale. At smaller scales, we surveyed four fields of natural co-occurrence, quantifying the spatial patterns at the field scale by randomly placed 1 × 1 m quadrats and at the smallest scale by detailing plant position within the quadrats. The patterns observed are strikingly different at the different scales. At the regional …

Mojave Applied Ecology Notes Spring 2011, Scott R. Abella, Ross Guida, S. D. Smith, Christopher L. Roberts, Haroon Stephen, William J. Smith, Zhongwei Liu, James S. Holland, Aurore Giguet

Mojave Applied Ecology Notes

Red brome distribution in the eastern Mojave Desert, A look at the UNLV xeric gardens and Marjorie Barrick museum, Summary of recent science synthesis efforts

Mojave Applied Ecology Notes Fall 2010, Adria Decorte, Sharon Altman, Alex Suazo

Mojave Applied Ecology Notes

Adria DeCorte defense, Mojave desert inventory and monitoring mapping project, effect of burial depth on Brassica tournefortii seeds

Japanese Stiltgrass: An Invasive Plant On The Move, Emily S.J. Rauschert, Andrea N. Nord

Biological, Geological, and Environmental Faculty Publications

No abstract provided.

Mojave Applied Ecology Notes Spring 2010, Anna San, Donovan J. Craig, Lindsay P. Chiquoine, Scott R. Abella, E. Cayenne Engel, Christina L. Lund, Jessica E. Spencer, Edward P. Weber Ph.D, Jill E. Craig

Mojave Applied Ecology Notes

Seed removal rates of Sahara mustard by rodents and ants, Mojave Desert Network exotic invasive inventory, gypsum roadside disturbance restoration update, new paper out on post-fire plant establishment, UNLV establishes school of environmental and public affairs

Slow Spread Of The Aggressive Invader, Microstegium Vimineum (Japanese Stiltgrass), Emily S.J. Rauschert, David A. Mortensen, Ottar N. Bjørnstad, Andrea N. Nord, Nora Peskin

Biological, Geological, and Environmental Faculty Publications

Microstegium vimineum (Japanese stiltgrass) is a non-native weed whose rapid invasion threatens native diversity and regeneration in forests. Using data from a 4 year experiment tracking new invasions in different habitats, we developed a spatial model of patch growth, using maximum likelihood techniques to estimate dispersal and population growth parameters. The patches expanded surprisingly slowly: in the final year, the majority of new seedlings were still within 1 m of the original patch. The influence of habitat was not as strong as anticipated, although patches created in roadside and wet meadow habitats tended to expand more rapidly and had greater …

The Role Of Adaptive Trans-Generational Plasticity In Biological Invasions Of Plants, Andrew R. Dyer, Cynthia S. Brown, Erin K. Espeland, John K. Mckay, Harald Meimberg, Kevin J. Rice

Faculty Publications

High-impact biological invasions often involve establishment and spread in disturbed, high-resource patches followed by establishment and spread in biotically or abiotically stressful areas. Evolutionary change may be required for the second phase of invasion (establishment and spread in stressful areas) to occur. When species have low genetic diversity and short selection history, within-generation phenotypic plasticity is often cited as the mechanism through which spread across multiple habitat types can occur. We show that trans-generational plasticity (TGP) can result in pre-adapted progeny that exhibit traits associated with increased fitness both in high-resource patches and in stressful conditions. In the invasive sedge, …

Mojave Applied Ecology Notes Winter 2010, Scott R. Abella, E. Cayenne Engel

Mojave Applied Ecology Notes

Native species interactions with red brome (Bromus rubens), undergraduate and graduate programs at UNLV, what’s growing in the greenhouse?

Mojave Applied Ecology Notes Fall 2009, Tom Monaco, Scott R. Abella, Amber Lee, James E. Deacon

Mojave Applied Ecology Notes

USDA working to manage invasive annual grasses, effects of heat and smoke on red brome soil seed bank, how burial depth and substrate affect germination of Sahara mustard and red brome, environmental effects of the southern Nevada groundwater project

Mojave Applied Ecology Notes Spring 2009, Russell Scofield, Michele Slaton Ph.D, Alexis Suazo, Donovan J. Craig

Mojave Applied Ecology Notes

California desert managers group, vegetation monitoring in Death Valley, undergraduate research symposium at UNLV, response of Sahara mustard to water and disturbance, JFS update

Mojave Applied Ecology Notes Summer 2008, Doug Merkler, Scott R. Abella, Dianne N. Bangle, Donovan J. Craig, Jessica E. Spencer, Alex Suazo

Mojave Applied Ecology Notes

Soil climate project, rare plant monitoring, JFS update, granivory and Sahara mustard

Mojave Applied Ecology Notes Spring 2008, Lesley Defalco, E. Cayenne Engel, Scott R. Abella, Jessica E. Spencer, Jill E. Craig

Mojave Applied Ecology Notes

Post-fire restoration, fire chronosequence study, Joint Fire Science update, Weed Sentry program and DNWR surveys

Mojave Applied Ecology Notes Winter 2008, Scott R. Abella, E. Cayenne Engel, Jill E. Craig

Mojave Applied Ecology Notes

Mojave Desert collaborative projects, fire history in Spring Mountains, Northshore Road rehabilitation, wildfires and invasive plants in American deserts conference, weed sentry surveys

Effects Of Density On Timing Of Emergence And Its Consequences For Survival And Growth In Two Communities Of Annual Plants, Roy Turkington, Deborah E. Goldberg, Linda Olsvig-Whittaker, Andrew R. Dyer

Faculty Publications

We tested whether increasing seed density results in a change in the timing of emergence in two communities of sand dune annual plants in Israel. Specifically we tested (i) if emergence is accelerated or delayed due to high seed density. We also tested two predictions about the consequences of changes in the timing of emergence; (ii) seedlings emerging earlier will have higher survival and growth; (iii) the advantage of earlier emergence increases as seed density increases. We examined these predictions for both monocots and dicots growing under different irrigation regimes and using species from a desert and a semi-arid community …

Using Upper Boundary Constraints To Quantify Competitive Response Of Desert Annuals, Laura M. Lessin, Andrew R. Dyer, Deborah E. Goldberg

Faculty Publications

Using a target-neighborhood approach with six annual dicot species in the Negev Desert of Israel, we tested whether neighborhood biomass constrained the upper limit of plant performance and if the slope of the upper boundary was correlated to species trait means, such as relative growth rate (RGR) and seed mass. Target individuals were measured in early spring and then collected at the onset of the dry season along with all naturally occurring neighbors within a 5-cm radius of the target. Using a minimum of 50 samples for each of the six target species, we found no significant relationships between target …

Effects Of Competition On Resource Availability And Growth Of A California Bunchgrass, Andrew R. Dyer, Kevin J. Rice

Faculty Publications

In California, little is known about the sensitivity of native bunchgrasses to competition or to changes in resource availability. We investigated the effect of nonnative annual vegetation on resource availability and growth of a native bunchgrass, Nassella pulchra, in a pair of factorial field experiments that incorporated effects of both interspecific and intraspecific competition as well as variation in soil depth. Plots of differing target densities and neighborhoods were used to assess changes in aboveground (light) and belowground (water) resource availability over multiple seasons in two sites with differing soil depth. N. pulchra grown without interspecific competitors grew larger …

Intraspecific And Diffuse Competition: The Response Of Nassella Pulchra In A California Grassland, Andrew R. Dyer, Kevin J. Rice

Faculty Publications

In inland California grasslands, the high densities of alien annual species have altered the growing environment for native perennial grasses. Using variable-density plots, we measured the influence of intraspecific competition (conspecifics only) and diffuse competition (mixed-composition neighborhoods that include conspecifics) on growth and survival of Nassella pulchra, purple needlegrass. We assessed the effects of intraspecific and diffuse competition in weeded plots and unweeded plots, respectively, across a density gradient of N. pulchra plants (16–356 plants/m2). We used summer fire and spring sheep grazing to reduce diffuse competition in unweeded plots. The potential effect of rooting volume on competitive interactions …

Macrophyte-Macroinvertebrate Interactions In A Lentic Ecosystem And The Effect Of Fluridone Treatment To Control Myriophyllum Spicatum L., Gregory J. Moeller

Dissertations and Theses @ UNI

Myriophyllum spicatum L. is an exotic macrophyte that can become pestiferous in lentic ecosystems. Two field studies were conducted to investigate: 1) epiphytic macroinvertebrates associated with M. spicatum and native macrophytes; and 2) epiphytic macroinvertebrate community response to fluridone treatment for M. spicatum control.

In the first study evaluating epiphytic macroinvertebrates associated with M. spicatum and native macrophytes, triplicate samples were collected at three sites in both Auburn and Zumbra Lakes, Minnesota, USA. One site in each lake contained primarily M. spicatum, the second site contained M. spicatum and native vegetation, and the third site was dominated by native …

The Effect Of Applied Nitrogen And Subterranean Clover On The Growth Of Doublegee, D J. Gilbey

Journal of the Department of Agriculture, Western Australia, Series 4

Until 20 years ago doublegees in Western Australia were mainly confined to the red-brown earth soils of the wheatbelt.

Since then, they have spread to light loamy sand soils in the wheatbelt, many of which have carried subterranean clover from the mid-1940s onwards.

It has been widely presumed that the spread of doublegees on to the lighter sandy soils of W.A. can be associated with the establishment of subterranean clover on these soils.

This report summarises the results of a glasshouse experiment on the effect of clover and nitrogen on the growth of doublegee.

The Grasses Of Nebraska, Charles E. Bessey, Robert Bolin , Depositor

School of Biological Sciences: Faculty Publications

Dr Bessey was the Nebraska State Botanist and Professor of Botany at University of Nebraska. This report contains a classification list of grasses found in the state and brief comments on the usefulness of the various grasses.