Digital Commons Network^™

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 …

Effects Of Short-Term Soil Conditioning By Cheatgrass And Western Wheatgrass, James J. O'Connor, Janet S. Prevey

The Prairie Naturalist

The exotic grass Bromus tectorum (cheatgrass) is a ubiquitous invader in the western USA. Cheatgrass is a proficient competitor, frequently displacing native plants, forming monotypic stands and reducing biodiversity in ecosystems it invades. Our experiment tested whether short-term soil modification by cheatgrass and a predominant native grass, Pascopyrum smithii (western wheatgrass), affected subsequent growth of both species. We compared productivity of cheatgrass and western wheatgrass by harvesting aboveground biomass of plants grown in either cheatgrass- or western wheatgrass-conditioned soils over two simulated growing seasons. Results indicated that cheatgrass soils do not inhibit the productivity of the native grass, but do …

Allelopathy In The Non-Native Macrophyte, Myriophyllum Spicatum And Its Influence On Trophic Dynamics In Aquatic Systems, Daniel J. Sullivan

Theses and Dissertations

Non-native macrophytes structurally impact aquatic assemblages, yet little is known regarding how they influence energy pathways in freshwater ecosystems. Allelopathy in Eurasian watermilfoil- Myriophyllum spicatum has been shown to target basal epiphytic organisms resulting in differences in assemblage structure of colonizing epiphyton between M. spicatum and native M. sibiricum. I conducted a growth chamber experiment to investigate the hypothesis that differences in assemblage structure of colonizing epiphyton between these two macrophytes influence trophic dynamics within aquatic systems. My data suggest M. spicatum produces higher concentrations of allelochemicals, resulting in a more diverse epiphytic assemblage compared to M. sibiricum. This could …

Factors Influencing Asiatic Oak Weevil Interactions With Native Ecosystem Engineers Over Time, Daniel Rothschild O'Brien

Theses

I sought to build a model to predict current and future abundance of Asiatic oak weevil (Coleoptera: Curculionidae: Cyrtepistomus castaneus) by using the relative abundance of leaf tying and leaf rolling caterpillars. The Asiatic oak weevil is an exotic species that has been observed inside leaf ties and leaf rolls made by native Lepidoptera caterpillars. Chapter one is a review of the known relationships between animal constructs and exotic species. Within this review I transition from natural structures, to animal architects, and to ecosystem engineers and how they have a population dynamic impact on the invasive species. I also discuss …

Utilization Of The Invasive Alga Gracilaria Vermiculophylla (Ohmi) Papenfuss By The Native Mud Snail Ilyanassa Obsoleta (Say), Michele Guidone, Christine Newton, Carol S. Thornber

Biology Faculty Publications

The recent invasions of the red alga, Gracilaria vermiculophylla, to the Atlantic and Eastern Pacific Oceans have the potential to significantly alter intertidal and subtidal soft sediment communities. In particular, G. vermiculophylla increases habitat complexity and provides a novel hard substrate in an otherwise two dimensional habitat. Following our observations that the native omnivorous mud snail Ilyanassa obsoleta utilizes G. vermiculophylla for egg capsule deposition, our field surveys demonstrated that the in situ abundance of egg capsules on G. vermiculophylla matched abundances on a native alga Ceramium virgatumandwere at least 11–50 times greater than on all other co-occurring macrophytes. Additionally, …

The Effects Of Invasive Plants On Biodiversity Across Spatial Scales, Kristin Irene Powell

All Theses and Dissertations (ETDs)

Although introduced plant species are often considered to be one of the most notable anthropogenic threats to biodiversity, their influence on biodiversity remains controversial. Some studies have shown large declines in biodiversity in plant-invaded areas, whereas others have noted that plant invasions are rarely implicated as the cause of species extinctions. This dissertation aims to synthesize this seemingly conflicting literature on the effects of invasive plants on biodiversity. The overarching hypothesis in this research is that the effect of invasive plant species on biodiversity is scale-dependent, and the discrepancy among studies can be explained by a difference in the scales …

A Survey Of Invasive Exotic Ants Found On Hawaiian Islands: Spatial Distributions And Patterns Of Association, Camie Frandsen Martin

Theses and Dissertations

An intensive sampling of all ant species encountered on 6 Hawaiian Islands: Big Island, Maui, Oahu, Kauai, Molokai, and Lanai took place between 1988 and 1996. Species presence and absence was recorded at each site. Using remote sensing, variables were added insitu and used throughout my analysis. Species accumulation curves suggest that sampling was comprehensive. There is a significant trend between island area and species richness which validates the Theory of Island Biogeography for invasive species. Islands were found to be significantly nested by area, order, and tourism. Cluster analysis shows a link between elevation, land-use and island, and species …

Challenges In Predicting The Future Distributions Of Invasive Plant Species, Chad C. Jones

Botany Faculty Publications

Species distribution models (SDMs) are increasingly used to predict distributions of invasive species. If successful, these models can help managers target limited resources for monitoring and controlling invasive species to areas of high invasion risk. Model accuracy is usually determined using current species distributions, but because invasive species are not at equilibrium with the environment, high current accuracy may not indicate high future accuracy. I used 1982 species distribution data from Bolleswood Natural Area, Connecticut, USA, to create SDMs for two forest invaders, Celastrus orbiculatus and Rosa multiflora. I then used more recent data, from 1992 and 2002, as validation …

Macrophyte Communities Of Lake Winnebago: Baseline Study Of Species Composition With Abundances And Water Quality Conditions, Mackenzie Kessenich

Lawrence University Honors Projects

Historical records from Lake Winnebago show minimal macrophyte growth; however, reports from recent years claim that macrophyte growth in some areas of the lake has reached nuisance levels. This study aimed to investigate the species of macrophytes present and their abundances in four near-shore locations, as well as measurements of multiple water quality conditions. Rake sampling was used to identify species and quantify their abundances and distributions. In addition, data were collected on light penetration, Secchi depths, and suspended algae chlorophyll concentrations at each site. These data from shallow near-shore sites reveal trends in changing water clarity and light penetration …

Land Use, Landscapes, And Biological Invasions, Karie L. Decker, Craig R. Allen, Leonardo Acosta, Michelle L. Hellman, Christopher F. Jorgensen, Ryan J. Stutzman, Kody M. Unstad, Amy Williams, Matthew Yans

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

The negative effect of invasive species on native species, communities, and ecosystems is widely recognized, and the economic effects in the United States are estimated to be billions of dollars annually. Studies often examine traits of nonnative species or examine what makes a particular habitat invasible. To better understand the factors governing invasions, we used the flora of Nebraska to characterize and compare native and nonnative plant occurrences throughout the state. In addition, we assessed four critical landscape predictors of nonnative plant richness: human population size and three land cover attributes that included percentage of grassland, percentage of agriculture, and …

Land Use, Landscapes, And Biological Invasions, Karie L. Decker, Craig R. Allen, Leonardo Acosta, Michelle L. Hellman, Christopher F. Jorgensen, Ryan Stutzman, Kody M. Unstad, Amy R. Williams, Matthew W. Yans

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

The negative effect of invasive species on native species, communities, and ecosystems is widely recognized, and the economic effects in the United States are estimated to be billions of dollars annually. Studies often examine traits of nonnative species or examine what makes a particular habitat invasible. To better understand the factors governing invasions, we used the flora of Nebraska to characterize and compare native and nonnative plant occurrences throughout the state. In addition, we assessed four critical landscape predictors of nonnative plant richness: human population size and three land cover attributes that included percentage of grassland, percentage of agriculture, and …

Role Of Belowground Fungal Mutualisms And Nutrient Cycling Alteration In Invasion Success Of Polygonum Cuspidatum Sieb. & Zucc. (Polygonaceae) In The Eastern United States, Gretchen Addington

All Theses

Plant species invasion is problematic around the world due to its negative effects on native plant biodiversity, ecosystem function, and ecosystem stability. Understanding the mechanisms of plant species invasion is necessary to predict new invasions and to control current problematic species. Polygonum cuspidatum Sieb. & Zucc. (Polygonaceae, Japanese Knotweed) is an invasive species found in 40 of the 50 United States and listed as a noxious species in nine states. It is known to exclude native plant communities, and its eradication is nearly impossible. The extensive negative effects associated with this species make understanding its mechanism of invasion a prerogative. …

Usage And Development Of Molecular Markers For Investigation Of The Population And Ecological Genetics Of Bromus Tectorum L., Keith R. Merrill

Theses and Dissertations

This thesis includes two studies: The first examined patterns of neutral genetic diversity within Bromus tectorum L. across the IMW region, and uses patterns of microsatellite (SSR) genotype distribution to make inferences about the respective roles of adaptively significant genetic variation, adaptive phenotypic plasticity, and facultative outcrossing in the ongoing invasion and recent range expansion of B. tectorum. It has been previously demonstrated that, due to extremely low outcrossing rates, it is possible to characterize individual genotypes of this species using four SSR loci. We sampled 20 individuals from each of 96 B. tectorum populations (classified by region and …

Combining Local- And Large-Scale Models To Predict The Distributions Of Invasive Plant Species, Chad C. Jones, Steven A. Acker, Charles B. Halpern

Botany Faculty Publications

Habitat-distribution models are increasingly used to predict the potential distributions of invasive species and to inform monitoring. However, these models assume that species are in equilibrium with the environment, which is clearly not true for most invasive species. Although this assumption is frequently acknowledged, solutions have not been adequately addressed. There are several potential methods for improving habitat-distribution models. Models that require only presence data may be more effective for invasive species, but this assumption has rarely been tested. In addition, combining modeling types to form ‘ensemble’ models may improve the accuracy of predictions. However, even with these improvements, models …

Cruise Foraging Of Invasive Chameleon (Chamaeleo Jacksonii Xantholophus) In Hawai’I, Travis J. Hagey, Jonathan B. Losos, Luke Harmon

Biology

We quantified the foraging behavior of the Jackson’s chameleon (Chamaeleo jacksonii xantholophus), an invasive insectivorous lizard species in Hawai’i. Using video taken in the field, we focused on percent time moving, moves per minute, and movement speeds. Our results supported previous findings that chameleons are ‘‘cruise foragers’’ (sensu Butler, 2005), a foraging behavior unlike almost all other species of lizards.

Biological Control: Effects Of Tyria Jacobaeae On The Population Dynamics Of Senecio Jacobaea In Northwest Montana, Kimberly Kay Crider

Graduate Student Theses, Dissertations, & Professional Papers

Biological control, using introduced, specialist insects is a common strategy for controlling plant invasions. However, the efficacy of biological control agents in controlling their host plants is rarely quantified population level. I quantified the impact of a specialist biological control agent, the cinnabar moth (Tyria jacobaeae) on its host plant, tansy ragwort (Senecio jacobaea) in northwest Montana. Cinnabar moth damage and its effects on important plant vital rates were tested with and without specialist herbivores. The presence of moth larvae corresponded to a reduction in population growth rates to less than one, compared to herbivore-free controls, indicating the potential for …

Biofuels: Cultivating Energy, Not Invasive Species, Invasive Species Advisory Committee

National Invasive Species Council

Biofuels: Cultivating Energy, not Invasive Species, approved by ISAC on August 11, 2009

ISSUE

To provide alternatives to petroleum-based energy, the United States government has mandated a greater proportion of plant-based biofuels be integrated into its energy portfolio. However, certain plant species being proposed for biofuel production in the United States are invasive species or are likely to escape cultivation and become invasive. United States Executive Order (EO) 131121 defines invasive species as “alien [non-native] species whose introduction does or is likely to cause economic or environmental harm or harm to human health” and states: “Each Federal agency whose actions …

Potential For Introduced-Range Expansion Of Chinese Tallow Tree (Triadica Sebifera) In The Southeastern United States, Isaac Park

All Theses

The potential for populations of invasive plants to differ in their response to stressful environmental conditions or in their invasiveness is an underexplored issue in determining introduced species' range limits. Introduced genotypes might differ in their response to freezing temperatures, soil type, or differing biotic factors within their introduced range. We examined the potential of Chinese tallow tree seeds (Triadica sebifera (L.) Small) collected from two genetically distinct areas of its introduced range in the United States (North Carolina and South Carolina) as well as from the northern and southern portions of its native range in China to germinate and …

Consequences Of Vegetation Change On The Dynamics Of Labile Organic Matter And Soil Nitrogen Cycling In A Semiarid Ecosystem, Toby D. Hooker

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Sagebrush-dominated ecosystems are being transformed by wildfire, rangeland improvement techniques, and exotic plant invasions. These disturbances have substantial effects on the composition and structure of native vegetation, but the effects on ecosystem C and N dynamics are poorly understood. To examine whether differences in dominant vegetation affect the quantity and quality of plant organic matter inputs to soil, ecosystem C and N pools and rates of plant turnover were compared among historically grazed Wyoming big sagebrush, introduced perennial crested wheatgrass, and invasive annual cheatgrass communities. Since low soil moisture during the summer may inhibit the microbial colonization of plant detrital …

Jamaican Nightshade (Solanum Jamaicense): A Threat To Florida's Hammocks, Rodrigo Diaz, William A. Overholt, Kenneth Langeland

Faculty Publications

Jamaican nightshade is a prickly, perennial, invasive shrub in central and southern peninsular Florida. It was first seen in Florida in 1930 near St. Cloud, and has since been reported at several other locations in the state. Jamaican nightshade is primarily found in wooded habitats, where it can quickly become dominant in the understory, but it also occasionally grows in isolated patches in the open. Although the distribution of Jamaican nightshade does not appear to be rapidly expanding in Florida, land mangers should be made aware of the potential of this weed to establish at new sites, and initiate control …

The Effects Of The Invasive Exotic Chinese Tallow Tree (Triadica Sebifera) On Amphibians And Aquatic Invertebrates, Norman Leonard

LSU New Orleans Theses and Dissertations

This dissertation addresses the question of how leaf litter from trees affects animals that live in aquatic environments, with an emphasis on the effect of Chinese tallow (Triadica sebifera) leaf litter on anuran larvae (i.e., frog tadpoles). This question is important to our understanding of how allochthonous inputs to aquatic habitats drive biodiversity in wetlands. It also addresses a timely conservation concern in southeastern Louisiana where invasion by Chinese tallow trees (Triadica sebifera) is displacing native trees. The invasion process is homogenizing forest composition and changing the quantity and quality of litter inputs to ponds from those produced by a …

Assessment Of Four Years Of Marsh Restoration At The Jones Farm Experimental Restoration Facility In Northeast Ohio: Water Quality, Plant Community Development, And Adaptive Management, Jake J. Grossman

Honors Papers

In order to characterize water quality, plant community diversity, and invasive species management at a restored wetland, I have analyzed data collected from June 2004 to August 2007 at the George Jones Memorial Farm in New Russia Township, Ohio. The Jones wetlands site is comprised of six emergent, herbaceous marshes that were restored on an old-field site in 2003. The six cells were constructed using a uniform physical restoration treatment, managed uniformly for invasive species, and replanted using three planting treatments. Each planting treatment was applied to two wetlands; treatments included two designer plantings of native taxa and one self-designing …

The Decline Of Fowler's Toad (Bufo Fowleri) In Southern Louisiana: Molecular Genetics, Field Experiments And Landscape Studies, Laura Sanders Vogel

LSU New Orleans Theses and Dissertations

Two of the most pervasive threats to species biodiversity are invasive species and habitat loss and degradation. Invasive species are often relatively insensitive to disturbance and many expand their range into disturbed and fragmented habitats. This dissertation uses an interdisciplinary approach to investigate how anthropogenic habitat disturbance is precipitating a range expansion in an invasive toad species, Bufo nebulifer, which is driving a decline in its native congener, B. fowleri. I employed a remote sensing and GIS study using historical data to compare changes in the two species distributions and habitat changes, a molecular genetic study to identify interspecific hybrids …

Ecology Of An Invasive Predator In Hawaii, Steven C. Hess, Heidi Hansen, Paul C. Banko

Managing Vertebrate Invasive Species

Cats (Felis catus) brought to Hawaii in the 1700s now occupy most habitats throughout the islands, including montane and sublapine zones. We studied home range, population genetics, diseases, and diet of feral cats on Hawai`i Island. Feral cats on Mauna Kea live in low densities and exhibit some of the largest reported home ranges. While 95% kernel home range estimates for 4 males ( x = 1418 ha) were nearly twice as large as 3 female home ranges ( x = 772 ha), one male maintained a home range of 2050 ha. Population genetics revealed that Mauna Kea …

Predicting Spotted Knapweed (Centaurea Maculosa) Range Expansion Near Missoula Montana Using Localized Climate And Elevation Data, William Frank Preston Cumming

Graduate Student Theses, Dissertations, & Professional Papers

Since the 1920s spotted knapweed (Centaurea maculosa) has adapted to a variety of habitats, including pastureland, rangeland, hay land, open forests, road sides, and ditches. In 2003 this plant species dominated more than five million acres in Montana, half of the total infestation of noxious weeds in the state. This project demonstrates the utility of using downscaled Parameter-elevation Regressions on Independent Slopes Model (PRISM) data for predicting vegetation movement within a 2°×2° geographical area surrounding Missoula County, Montana. This localized climate change data was correlated against current knapweed range using validation data from the Volunteer for Wilderness Program at the …

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 …