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Disturbance

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Patterns, Mechanisms, And Characterization Of Carbon Cycling Stability Following Partial Forest Disturbance, Kayla C. Mathes Jan 2023

Patterns, Mechanisms, And Characterization Of Carbon Cycling Stability Following Partial Forest Disturbance, Kayla C. Mathes

Theses and Dissertations

Among the most essential questions in the era of climate change is how the forest carbon (C) cycle will respond to an increase in the extent of biotic disturbances from insects and pathogens. While research has focused on stand-replacing disturbance regimes, less is known about C cycling stability following partial disturbances that produce gradients of disturbance severity. Belowground C cycling responses to disturbance are especially poorly understood, even though temperate forest soils contain up to 50% of total ecosystem C and soil respiration (Rs) accounts for more than half of temperate forest C loss. Interpreting trends and mechanisms …


Biodiversity And Fire In Shortgrass Steppe, Paulette L. Ford Dec 2021

Biodiversity And Fire In Shortgrass Steppe, Paulette L. Ford

IGC Proceedings (1997-2023)

Effects of fire at two levels of intensity on beetle diversity in shortgrass steppe were examined. The experimental design was completely randomized, with 3 treatments and 4 replicates per treatment. Treatments were two levels of fire 1) dormant-season fire (relatively hot), and 2) growing-season fire (relatively cool), and unburned plots. The response variables were arthropod species richness and abundance. The intermediate disturbance hypothesis predicts that maximum species richness occurs at intermediate levels of disturbance. Data obtained in this study support that prediction. Species richness was higher on plots of intermediate fire intensity than the more intensely burned plots, and almost …


Does Invasion Science Encompass The Invaded Range? A Comparison Of The Geographies Of Invasion Science Versus Management In The U.S., Lara Munro Dec 2020

Does Invasion Science Encompass The Invaded Range? A Comparison Of The Geographies Of Invasion Science Versus Management In The U.S., Lara Munro

Masters Theses

Biases in invasion science lead to a taxonomic focus on plants, particularly a subset of well-studied plants, and a geographic focus on invasions in Europe and North America. Geographic biases could also cause some branches of invasion science to focus on a subset of environmental conditions in the invaded range, potentially leading to an incomplete understanding of the ecology and management of plant invasions. While broader, country-level geographic biases are well known, it is unclear whether these biases extend to a finer scale and thus affect research within the invaded range. This study assessed whether research sites for ten well-studied …


Wetland Edge Trampled By American Bison (Bos Bison) Used As Basking Site For Painted Turtles (Chrysemys Picta), Keith Geluso, Carter Kruse, Mary Harner Oct 2020

Wetland Edge Trampled By American Bison (Bos Bison) Used As Basking Site For Painted Turtles (Chrysemys Picta), Keith Geluso, Carter Kruse, Mary Harner

Transactions of the Nebraska Academy of Sciences and Affiliated Societies

Prairies of the Great Plains once were influenced by large-scale disturbances, such as fire and herbivory by large ungulates, that promoted ecosystem functioning. American Bison (Bos bison) created many types of disturbances as they traversed grassland landscapes. Trampling, a common type of bison disturbance, occurred when large herds moved through an area denuding aboveground vegetation, exposing prairie soils, and restarting succession. Bison reintroductions now allow researchers to use contemporary observations to examine influences of these large, hoofed mammals on system functions. Herein, we report on the immediate benefit of trampling along a wetland edge for another vertebrate species. …


Characterizing The Impacts Of The Invasive Hemlock Woolly Adelgid On The Forest Structure Of New England, Peter Brehm Boucher May 2020

Characterizing The Impacts Of The Invasive Hemlock Woolly Adelgid On The Forest Structure Of New England, Peter Brehm Boucher

Graduate Doctoral Dissertations

Climate change is raising winter temperatures in the Northeastern United States, both expanding the range of an invasive pest, the hemlock woolly adelgid (HWA; Adelges tsugae), and threatening the survival of its host species, eastern hemlock (Tsuga canadensis). As a foundation species, hemlock trees underlie a distinct network of ecological, biogeochemical, and structural systems that will likely disappear as the HWA infestation spreads northward. Remote sensing can offer new perspectives on this regional transition, recording the progressive loss of an ecological foundation species and the transition of evergreen hemlock forest to mixed deciduous forest over the course of the infestation. …


The Effects Of Prescribed Burning And Microhabitat Type On Ant (Formicidae) Functional Groups And A Survey Of Ants In The Dr. Howard Reynolds Nature Area (A Mixed Grass Prairie), Ashley N. Durr Jan 2020

The Effects Of Prescribed Burning And Microhabitat Type On Ant (Formicidae) Functional Groups And A Survey Of Ants In The Dr. Howard Reynolds Nature Area (A Mixed Grass Prairie), Ashley N. Durr

Master's Theses

This project sought to understand how prescribed burning and microhabitat type impacts Kansas ant functional groups and also whether prescribed burning in different microhabitat types altered the burn’s impact on those functional groups. The Dr. Howard Reynolds Nature Trail, located in Hays, Kansas, was burned in the spring of 2019. The area consists of 2 distinct habitat types: a dry, mixed-grass dominated uphill area and a moist, densely vegetated downhill area. Pitfall trapping was conducted during the summers of the year prior to the burn (2018) and the year following the burn (2019). 15 pitfall traps were spread across each …


Wildfire Alters Spatial Patterns Of Available Soil Nitrogen And Understory Environments In A Valley Boreal Larch Forest, Jianjian Kong, Jian Yang, Bo Liu, Lin Qi Jan 2019

Wildfire Alters Spatial Patterns Of Available Soil Nitrogen And Understory Environments In A Valley Boreal Larch Forest, Jianjian Kong, Jian Yang, Bo Liu, Lin Qi

Forestry and Natural Resources Faculty Publications

Wildfire, a primary natural disturbance in many forests, affects soil nutrient availability and spatial distributions of forest plants. However, post-fire changes in soil nutrients and spatial patterns of understory environments at fine scales are poorly understood. Here, we characterized spatial patterns of soil nitrogen availability and site characteristics at a 3-year-post-fire and an unburned site in a valley boreal larch forest. We also examined the relationship between soil nitrogen availability and site characteristics. The results showed that the burned site had higher NO3 and lower NH4+ than the control. The herb, litter and coarse wood debris …


The Effect Of Environmental Perturbations On The Plant Phyllosphere Microbiome, Bram W. Stone Jan 2018

The Effect Of Environmental Perturbations On The Plant Phyllosphere Microbiome, Bram W. Stone

Electronic Theses and Dissertations

Applying ecological concepts to microbial communities has proved to be challenging, often revolving around the relative importance of stochastic and deterministic processes applied heterogeneously across the habitat in time or space. The phyllosphere is the aboveground surface of plants on which microbial communities, composed primarily of Bacteria, but also including Archaea and microbial eukaryotes, exist and is characterized by stochastic immigration balanced with strong selective forces. Variation in bacterial community composition was characterized across space and time, with special attention given to the exposure of phyllosphere communities to rain as a plausible mechanism of ecological disturbance. Bacterial communities were characterized …


Effects Of Wave Action On The Structure Of Fish Assemblages Across An Exposure Gradient, Lauren Liddon Aug 2017

Effects Of Wave Action On The Structure Of Fish Assemblages Across An Exposure Gradient, Lauren Liddon

Master's Theses

Disturbance affects the function and diversity of ecosystems. Increased wave exposure to salt marsh can disturb sediments and cause a loss of habitat. The purpose of this study was to explore the effects of increased wave exposure on diversity, abundance, and functional ecology of estuarine fishes. If increased wave exposure is acting as a disturbance to these habitats, ecological theory (Intermediate Disturbance Hypothesis) predicts that diversity will peak at intermediate frequencies and intensities of disturbance. Fish were sampled from 10 sites monthly for 6 years. The sites were assigned to different exposure categories (Open, Intermediate, and Sheltered) using an exposure …


Decadal Vegetation Succession Along A Chronosequence Within Eucalyptus Obliqua Wet Forest, Southern Tasmania, Christine Dobbin Apr 2017

Decadal Vegetation Succession Along A Chronosequence Within Eucalyptus Obliqua Wet Forest, Southern Tasmania, Christine Dobbin

Independent Study Project (ISP) Collection

Southern Tasmania is home to fire dependent mixed forests, which, if not maintained, will eventually be replaced by the rainforest understorey. Wet eucalypt forest succession after disturbance events was investigated through floristic and vertical measurements of four north facing chronosequence plots with labels describing the age class of each, from regrowth to mature sites. This study was possible due to the establishment of permanent 50m x 50m plots in 2007 for longitudinal monitoring and subsequent illustration of forest dynamics following disturbance, including clearfell burns and wildfire. The contents of this report are the comparative analyses of the findings from the …


Sandhill Crane Roost Selection, Human Disturbance, And Forage Resources, Aaron T. Pearse, Gary L. Krapu, David A. Brandt Nov 2016

Sandhill Crane Roost Selection, Human Disturbance, And Forage Resources, Aaron T. Pearse, Gary L. Krapu, David A. Brandt

USGS Northern Prairie Wildlife Research Center

Sites used for roosting represent a key habitat requirement for many species of birds because availability and quality of roost sites can influence individual fitness. Birds select roost sites based on numerous factors, requirements, and motivations, and selection of roosts can be dynamic in time and space because of various ecological and environmental influences. For sandhill cranes (Antigone canadensis) at their main spring staging area along the Platte River in south-central Nebraska, USA, past investigations of roosting cranes focuse donphysical channel characteristics related to perceived security as motivating roost distribution.We used 6,310 roost sites selected by 313 sandhill cranes over …


Beyond Bivariate Correlations: Three-Block Partial Least Squares Illustrated With Vegetation, Soil, And Topography, Daehyun Kim, Thomas J. Dewitt, César S. B. Costa, John A. Kupfer, Ryan W. Mcewan, J. Anthony Stallins Sep 2016

Beyond Bivariate Correlations: Three-Block Partial Least Squares Illustrated With Vegetation, Soil, And Topography, Daehyun Kim, Thomas J. Dewitt, César S. B. Costa, John A. Kupfer, Ryan W. Mcewan, J. Anthony Stallins

Ryan McEwan

Ecologists, particularly those engaged in biogeomorphic studies, often seek to connect data from three or more domains. Using three-block partial least squares regression, we present a procedure to quantify and define bi-variance and tri-variance of data blocks related to plant communities, their soil parameters, and topography. Bi-variance indicates the total amount of covariation between these three domains taken in pairs, whereas tri-variance refers to the common variance shared by all domains. We characterized relationships among three domains (plant communities, soil properties, topography) for a salt marsh, four coastal dunes, and two temperate forests spanning several regions in the world. We …


The Effect Of Disturbance And Freshwater Availability On Lower Florida Keys’ Coastal Forest Dynamics, Danielle E. Ogurcak Nov 2015

The Effect Of Disturbance And Freshwater Availability On Lower Florida Keys’ Coastal Forest Dynamics, Danielle E. Ogurcak

FIU Electronic Theses and Dissertations

Coastal forest retreat in the Florida Keys during the 20th century has been attributed to a combination of sea level rise and hurricane storm surge impacts, but the interactions between these two disturbances leading to forest decline are not well understood. The goal of my research was to assess their effects over a period spanning more than two decades, and to examine the relationships between these press and pulse disturbances and freshwater availability in pine rockland, hardwood hammock, and supratidal scrub communities. Impacts and recovery from two storm surges, Hurricanes Georges (1998) and Wilma (2005), were assessed with satellite-derived …


Beyond Bivariate Correlations: Three-Block Partial Least Squares Illustrated With Vegetation, Soil, And Topography, Daehyun Kim, Thomas J. Dewitt, César S. B. Costa, John A. Kupfer, Ryan W. Mcewan, J. Anthony Stallins Aug 2015

Beyond Bivariate Correlations: Three-Block Partial Least Squares Illustrated With Vegetation, Soil, And Topography, Daehyun Kim, Thomas J. Dewitt, César S. B. Costa, John A. Kupfer, Ryan W. Mcewan, J. Anthony Stallins

Biology Faculty Publications

Ecologists, particularly those engaged in biogeomorphic studies, often seek to connect data from three or more domains. Using three-block partial least squares regression, we present a procedure to quantify and define bi-variance and tri-variance of data blocks related to plant communities, their soil parameters, and topography. Bi-variance indicates the total amount of covariation between these three domains taken in pairs, whereas tri-variance refers to the common variance shared by all domains. We characterized relationships among three domains (plant communities, soil properties, topography) for a salt marsh, four coastal dunes, and two temperate forests spanning several regions in the world. We …


Remote Sensing Estimates Of Stand-Replacement Fires In Russia, 2002–2011, Alexander Krylov, Jessica L. Mccarty, Peter Potapov, Tatiana Loboda, Alexandra Tyukavina, Svetlana Turubanova, Matthew Hansen Oct 2014

Remote Sensing Estimates Of Stand-Replacement Fires In Russia, 2002–2011, Alexander Krylov, Jessica L. Mccarty, Peter Potapov, Tatiana Loboda, Alexandra Tyukavina, Svetlana Turubanova, Matthew Hansen

Michigan Tech Research Institute Publications

The presented study quantifies the proportion of stand-replacement fires in Russian forests through the integrated analysis of Landsat and Moderate Resolution Imaging Spectroradiometer (MODIS) data products. We employed 30 m Landsat Enhanced Thematic Mapper Plus derived tree canopy cover and decadal (2001–2012) forest cover loss (Hansen et al 2013 High-resolution global maps of 21st-century forest cover change Science 342 850–53) to identify forest extent and disturbance. These data were overlaid with 1 km MODIS active fire (earthdata.nasa.gov/data/near-real-time-data/firms) and 500 m regional burned area data (Loboda et al 2007 Regionally adaptable dNBR-based algorithm for burned area mapping from …


Can Fire Atlas Data Improve Species Distribution Model Projections?, Shawn M. Crimmins, Solomon Z. Dobrowski, Alison R. Mynsberge, Hugh D. Safford Jul 2014

Can Fire Atlas Data Improve Species Distribution Model Projections?, Shawn M. Crimmins, Solomon Z. Dobrowski, Alison R. Mynsberge, Hugh D. Safford

Forest Management Faculty Publications

Correlative species distribution models (SDMs) are widely used in studies of climate change impacts, yet are often criticized for failing to incorporate disturbance processes that can influence species distributions. Here we use two temporally independent data sets of vascular plant distributions, climate data, and fire atlas data to examine the influence of disturbance history on SDM projection accuracy through time in the mountain ranges of California, USA. We used hierarchical partitioning to examine the influence of fire occurrence on the distribution of 144 vascular plant species and built a suite of SDMs to examine how the inclusion of fire-related predictors …


An Ecological, Genetic, And Reproductive Study Of Big Bluestem (Andropogon Gerardii) Populations In The Carolinas, Robert Tompkins May 2011

An Ecological, Genetic, And Reproductive Study Of Big Bluestem (Andropogon Gerardii) Populations In The Carolinas, Robert Tompkins

All Dissertations

ABSTRACT
AN ECOLOGICAL, GENETIC, AND REPRODUCTIVE STUDY OF BIG BLUESTEM (ANDROPOGON GERARDII) POPULATIONS IN THE CAROLINAS
Andropogon gerardii (Big Bluestem) is a dominant grass of the North American tallgrass prairie and is also found in remnant populations in the eastern U.S., including North and South Carolina. This research included a systematic study of the ecology, genetics, and reproductive potential within and among A. gerardii populations in the Carolinas. Floristic composition and edaphic (soil) features were characterized for eight A. gerardii populations across various physiographic regions of North and South Carolina. A total of 362 quadrats (1 m x 1 m) …


Consumer Return Chronology Alters Recovery Trajectory Of Stream Ecosystem Structure And Function Following Drought, Justin N. Murdock, Keith B. Gido, Walter K. Dodds, Katie N. Bertrand, Matt R. Whiles Apr 2010

Consumer Return Chronology Alters Recovery Trajectory Of Stream Ecosystem Structure And Function Following Drought, Justin N. Murdock, Keith B. Gido, Walter K. Dodds, Katie N. Bertrand, Matt R. Whiles

Natural Resource Management Faculty Publications

Consumers are increasingly being recognized as important drivers of ecological succession, yet it is still hard to predict the nature and direction of consumer effects in nonequilibrium environments. We used stream consumer exclosures and large outdoor mesocosms to study the impact of macroconsumers (i.e., fish and crayfish) on recovery of intermittent prairie streams after drying. In the stream, macroconsumers altered system recovery trajectory by decreasing algal and macroinvertebrate biomass, primary productivity, and benthic nutrient uptake rates. However, macroconsumer influence was transient, and differences between exclosures and controls disappeared after 35 days. Introducing and removing macroconsumers after 28 days resulted mainly …


Severe Wind And Fire Regimes In Northern Forests: Historic Variability At The Regional Scale, Lisa A. Schulte-Moore, David J. Mladenoff Jan 2005

Severe Wind And Fire Regimes In Northern Forests: Historic Variability At The Regional Scale, Lisa A. Schulte-Moore, David J. Mladenoff

Lisa A. Schulte Moore

Within the northern Great Lakes region, mesoscale (10s to 100s of km2) forest patterning is driven by disturbance dynamics. Using original Public Land Survey (PLS) records in northern Wisconsin, USA, we study spatial patterns of wind and fire disturbances during the pre-Euroamerican settlement period (ca. 1850). Our goals were: (1) to determine how effectively wind and fire disturbance can be econstructed from the PLS, (2) to assess the roles of wind and fire in shaping vegetation patterns, (3) to evaluate landscape to regional controls of wind and fire regimes, and (4) to assess the potential for interactions between these disturbances. …


Effects Of Cattle Grazing On Woodlands In Central Iowa, Cathy Mabry Jan 2002

Effects Of Cattle Grazing On Woodlands In Central Iowa, Cathy Mabry

Journal of the Iowa Academy of Science: JIAS

Iowa's forests have undergone a dramatic decline in area since settlement by Europeans. Most of the remaining forests have been degraded by an assortment of human impacts, with cattle grazing the most prominent among them. Using a matched pairs study designed to control for environmental differences among plots, I examined the impact of cattle grazing on the forest understory, canopy trees, and tree regeneration. There were distinct groups of understory species associated with ungrazed and grazed plots. Species associated with ungrazed plots were all native and tended to be perennial herbs with fleshy roots. Ungrazed plots also had species preferring …


Long-Term Aspen Exclosures In The Yellowstone Ecosystem, Charles E. Kay Jan 2001

Long-Term Aspen Exclosures In The Yellowstone Ecosystem, Charles E. Kay

Aspen Bibliography

Aspen has been declining in the Yellowstone Ecosystem for more than 80 years. Some authors have suggested that aspen is a marginal plant community in Yellowstone and that recent climatic variation has adversely affected aspen, while others contend that excessive browsing by native ungulates is primarily responsible for aspen’s widespread decline. To test these hypotheses, I measured all the long-term aspen exclosures (n = 14) in the Yellowstone Ecosystem. Aspen stands inside all exclosures successfully produced new stems greater than 2 m tall without fire or other disturbance, while few outside stands successfully regenerated due to repeated browsing. Understory species …