Ecology and Evolutionary Biology Commons^™

From Pixels To Plants: Remote Sensing Of California Invasive Plants, Kenneth Rangel

Master's Projects and Capstones

Invasive plants cause significant impacts to ecosystems, the economy, and human health. California has experienced significant plant invasions and is well suited to future invasion because of its Mediterranean climate and human disturbance. Eradication or control of invasive plant species requires a detailed understanding of their spatial distribution, which typically involves on the ground surveys that can be expensive or inconsistent. Remote sensing offers a potential alternative or supplement to in-person invasive plant mapping. This study performed a comparative analysis of 41 remote sensing studies that mapped the distribution of California invasive plants. I found that while high spectral resolution …

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

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

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

Methods: We assessed the spread …

Examining The Invasion Of Bush Honeysuckle Through A Phylogenetic Analysis, Phoebe Bruffett

Biological Sciences Undergraduate Honors Theses

The mechanisms underlying the continual spread of invasive plants within their respective non-native ranges is a major focal point to invasion research. Many theories have been proposed to understand these invasions, each with different implications for the predicted range for invasive plants. Lonicera maackii provides an exceptional opportunity to examine the effectiveness of these theories to explain the trends of invasive plants. Lonicera maackii is native to eastern Asia, but has invaded much of the eastern United States, presenting a severe threat to the health of forest and other natural areas. Recent analysis of the climatic envelopes uncovered a significant …

Island Invasion: The Silent Crisis In Hawaii, Sophia Janssen

Pomona Senior Theses

Keeping out invasive species may, upon first review, seem like a trivial environmental cry from ecologists and deep environmentalists; a belated wish to return to an undeveloped world where nature was pristine. However invasive species create problems that impact all of us and can have far more severe consequences than changing a stunning landscape. These problems are heightened in islands like Hawaii, where the fragile ecosystems have developed over centuries of evolution and adaptation. The introduction of a disease-carrying mosquito can put the people of Hawaii at risk to many vector-born illnesses and create an epidemic, taking human life. The …

Mitigating Bioiversity Loss Of Native Plants, Jamie Ana Grigonis

Student Theses 2015-Present

Growing up harvesting from my own vegetable garden and going from nursery to nursery with my mother, it has been extremely evident that plant biodiversity is more than just privet along driveways and carnations in window boxes. Plant biodiversity is often overlooked but crucial to having a healthy and thriving environment. Without certain plants, our ecosystems will crumble and this needs to be addressed now while it’s still at a level we can grow from. In my internship I am working alongside the director of the Thain Family Forest at the New York Botanical Gardens in order to get a …

Salvinia Molesta: An Assessment Of The Effects And Methods Of Eradication, Arti Lal

Master's Projects and Capstones

Salvinia molesta is an invasive aquatic fern. It is now the second worse aquatic invader in the world. Since the 1930s, it has invaded most tropical and some temperate countries. S. molesta plants grow vegetatively and can increase in size rapidly. S. molesta can form thick mats of up to 1-meter-thick. There are a number of ways these thick mats negatively affect the environment: 1) reduce light to benthic organisms, 2) reduce oxygen in the water column for other organisms, 3) accumulate as organic matter at the bottom of the water column, 4) decrease nutrients for other organisms, and 5) …

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 …

Harvest Incentives: A Tool For Managing Aquatic Invasive Species, Bob Wiltshire, Nathan Stone, Marshall Meyers, Bill Hyatt, Lori Williams, Jason Goldberg, Susan Pasko, Leah Elwell

National Invasive Species Council

Conclusion

The success of any harvest incentive program to address aquatic invasive species will depend upon numerous biological, socioeconomic, and legal considerations. Programs that encourage harvest may be a successful management tool in targeting small, distinct populations; in high priority areas within a larger invasion; or they may play a supplementary role within larger control programs. Their use, however, will require careful review, planning, and monitoring to ensure success and that they do not unintentionally lead to further spread of invasive species, cause additional harm to native species, or waste valuable resources.

Use Of Seeded Exotic Grasslands By Wintering Birds, Andrew D. George, Timothy J. O'Connell, Karen R. Hickman, David M. Lesliee Jr.

The Prairie Naturalist

Despite widespread population declines of North American grassland birds, effects of anthropogenic disturbance on wintering habitat of this guild remain poorly understood. We compared avian abundance and habitat structure in fields planted to the exotic grass Old World bluestem (Bothriochloa ischaemum; OWB) to that in native mixed-grass prairie. During winters of 2007–2008 and 2008–2009, we conducted bird and vegetation surveys in six native grass and six OWB fields in Garfield, Grant, and Alfalfa counties, Oklahoma. We recorded 24 species of wintering birds in native fields and 14 species in OWB monocultures. While vegetation structure was similar between field …

Exploring The Seed Bank Dynamics Of Red Brome: Longevity, Density, And Relationship To Fire, Benjamin S. Jurand

UNLV Theses, Dissertations, Professional Papers, and Capstones

This research explores several untested aspects of the seed bank characteristics of red brome (Bromus rubens), an invasive annual grass in southwestern United States arid lands. Red brome is a formidable competitor to native plant species, both annual and perennial alike, and produces many seeds that germinate easily. The stalks of red brome contribute continuous-cover fuel loads that facilitate wildfires destructive to mature native Mojave Desert plant communities. This makes it a priority species for land managers, particularly when dealing with recovery after fire.

This project addressed questions related to the longevity of red brome seeds in soil seed banks …

Vegetation Characteristics Associated With Small Mammal Populations In The Las Vegas Wash, Christine Therese Herndon

UNLV Theses, Dissertations, Professional Papers, and Capstones

Percent litter, average litter depth, percent bare ground, vegetation density, vegetation canopy, and distance to an ecotone boundary were measured and compared to small mammal capture locations in the Las Vegas Wash. Neotoma lepida appear to be greatly dependent upon the foliage litter of T. ramosissima. Alternatively, ecotone boundaries appear to be the most important factor affecting Dipodomys merriami distributions. Peromyscus eremicus distributions may be predicted based on vegetation density and increased canopy during shorter, winter torpor periods. Chaetodipus penicillatus were consistently associated with dense, seed-bearing vegetation, although C. penicillatus is extremely opportunistic and vegetation density should not limit their …

A Study Of Invasive Species Cover Near Roads In A Red Rock Canyon Blackbrush Community, Christopher Keough

UNLV Theses, Dissertations, Professional Papers, and Capstones

The monitoring of Mojave Desert plant communities during and following disturbance is an important process that could provide invaluable information about disturbance/recovery regimes in similar arid environments across the globe. Blackbrush communities are of particular interest because of their low replacement rate, which makes them highly susceptible to disturbance. Roads in the Mojave Desert have been associated with soil compaction resulting in a lack of vegetation as well as an increase in invasive species cover in the immediate proximity. To investigate these statements, eight fifty-foot line transects were established in each of three plot types (perpendicular to dirt roads, perpendicular …

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

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 …