Biology Commons^™

Analysis Of Symptom Expressions And Transmission Rates Caused By The Plant Pathogen Phytophthora Ramorum On Native Chaparral Plants From The Genus Arctostaphylos, Bharati Gaonker

Natural Sciences and Mathematics | Biological Sciences Master's Theses

Phytophthora ramorum is the causal agent of Sudden Oak death (SOD), ramorum dieback and ramorum leaf blight which affect both forest environments and nurseries. This oomycete pathogen has had a huge economic impact on the nursery and lumber industry. Forests in California have experienced substantial mortality of oaks affecting the forest dynamics and diversity. Our research investigates four native species and two ornamental cultivars of plants, which belong to the genus Arctostaphylos (manzanita) and are considered to be new hosts for P. ramorum in the chaparral ecosystem of California. Symptom expression and transmission rates were analyzed on Arctostaphylos glauca, …

Soil Macroinvertebrates Responses To Wildfires In The Blue Ridge Mountains, Usa, Madeline Olliff

Biology Theses

Fire has been a prevalent disturbance on Earth for millions of years. Around the globe there are several regions that have become fire adapted, including the Southeastern United States. There have been few studies examining the effects of wildland fires on soil macroinvertebrates in the Blue Ridge Mountains, in spite of the importance of these animals to soil processes and their contributions to the biodiversity of these ecosystems. During the fall of 2016, the Southeastern USA experienced numerous, large wildfires. These fires offered an opportunity to study the effects of wildland fire on soil macroinvertebrates. We sampled sites from three …

Seed Rain–Successional Feedbacks In Wet Tropical Forests, Nohemi Huanca Nuñez, Robin L. Chazdon, Sabrina E. Russo

School of Biological Sciences: Faculty Publications

Abstract

Tropical forest regeneration after abandonment of former agricultural land depends critically on the input of tree seeds, yet seed dispersal is increasingly disrupted in contemporary human-modified landscapes. Here, we introduce the concept of seed rain–successional feedbacks as a deterministic process in which seed rain is shaped by successional dynamics internal to a forest site and that acts to reinforce priority effects. We used a combination of time series and chronosequence approaches to investigate how the quantity and taxonomic and functional composition of seed rain change during succession and to evaluate the strength of seed rain–successional feedbacks, relative to other …

Focus Stacking Images Of Morphological Character States For Differentiating The Adults Of Ixodes Affinis And Ixodes Scapularis (Acari: Ixodidae) In Areas Of Sympatry, Robyn M. Nadolny, Marcée Toliver, Holly D. Gaff, John G. Snodgrass, Richard G. Robbins

Biological Sciences Faculty Publications

Adult females and males of Ixodes affinis and Ixodes scapularis are illustrated by focus stacking image photography, and morphological character states are described that reliably differentiate the two species. In conjunction with other environmental cues, such as the questing phenology of adults, these characteristics will enable the rapid identification of adults of either sex along the southern Coastal Plain of the United States, where these species are sympatric.

The Interspecific Growth–Mortality Trade-Off Is Not A General Framework For Tropical Forest Community Structure, Sabrina E. Russo, Sean M. Mcmahon, Matteo Detto, Glenn Ledder, S. Joseph Wright, Richard S. Condit, Stuart J. Davies, Peter S. Ashton, Sarayudh Bunyavejchewin, Chia-Hao Chang-Yang, Sisira Ediriweera, Corneille E.N. Ewango, Christine Fletcher, Robin B. Foster, C.V. Savi Gunatilleke, I.A.U. Nimal Gunatilleke, Terese Hart, Chang-Fu Hseih, Stephen P. Hubbell, Akira Itoh, Abdul Rahman Kassim, Yao Tze Leong, Yi Ching Lin, Jean-Remy Makana, Mohizah Bt. Mohamad, Perry Ong, Anna Sugiyama, I-Fang Sun, Sylvester Tan, Jill Thompson, Takuo Yamakura, Sandra L. Yap, Jess K. Zimmerman

School of Biological Sciences: Faculty Publications

Resource allocation within trees is a zero-sum game. Unavoidable trade-offs dictate that allocation to growth-promoting functions curtails other functions, generating a gradient of investment in growth versus survival along which tree species align, known as the interspecific growth–mortality trade-off. This paradigm is widely accepted but not well established. Using demographic data for 1,111 tree species across ten tropical forests, we tested the generality of the growth–mortality trade-off and evaluated its underlying drivers using two species-specific parameters describing resource allocation strategies: tolerance of resource limitation and responsiveness of allocation to resource access. Globally, a canonical growth–mortality trade-off emerged, but the trade-off …

Seedling Growth And Soil Chemistry In A Chronosequence Of Forest Restoration From Agriculture, Michaela J. Woods, Sarah J. Frankenberg, Joseph R. Juodvalkis, Mary C. Lloyd, Meredith Cobb, Ryan Mcewan

Five Rivers MetroParks Collaboration Data Archive

Soils were collected from forest restorations that were 0, 7, 10, 50 and 100 years old and assessed for soil nutrients, chemistry, and enzymatic activity. Quercus macrocarpa seedlings were planted in each soil type, after 5 months of growth seedlings were destructively harvested. Seedling mass and the colonization rate of their roots by ectomycorrhizal fungi are reported.

The photo accompanying this data collection is of the researchers' germinating Quercus macrocarpa seeds.

Wildlife Forage Recovery Following Boreal Wildfire, Alexis Jorgensen, Jennifer Baltzer

Theses and Dissertations (Comprehensive)

Climate change is altering the boreal wildfire regime through increases in the extent and severity of burning and reductions in fire return intervals. These changes can alter the regeneration trajectory of canopy species and ground vegetation, with implications for wildlife habitat. There is some uncertainty about the timelines of when different animal species will use burned areas as their preferred forage taxa recover following fire, and how such recovery is mediated by environmental factors. Here, we aim to address these knowledge gaps through the following questions: 1) What are the main forage types consumed by boreal wildlife and how much …