Life Sciences Commons^™

Vegetation Response To Canopy Disturbance And Season Of Burn During Oak Woodland And Savanna Restoration In Tennessee, Andrew Lee Vander Yacht, Seth A. Barrioz, Patrick D. Keyser, Craig A. Harper, David Buckley, David A. Buehler, Roger D. Applegate

UT Extension publication

The removal of fire’s influence on plant community succession has resulted in the near disappearance of oak woodlands and savannas from the Appalachian region. Negative trends in associated plant and wildlife species could be reversed if these communities are restored, but management has been limited by inadequate canopy disturbance, resprouting of woody plants, and a lack of empirical research. To address these issues, we evaluated herbaceous and woody vegetation response on the

Cumberland Plateau in Tennessee to 5 replicated treatments involving canopy reduction and fire-season combinations and unmanaged controls. All categories of woody vegetation except large saplings density, but resprouting …

Effects Of Catastrophic Seagrass Loss And Predation Risk On The Ecological Structure And Resilience Of A Model Seagrass Ecosystem, Robert J. Nowicki

FIU Electronic Theses and Dissertations

As climate change continues, climactic extremes are predicted to become more frequent and intense, in some cases resulting in dramatic changes to ecosystems. The effects of climate change on ecosystems will be mediated, in part, by biotic interactions in those ecosystems. However, there is still considerable uncertainty about where and how such biotic interactions will be important in the context of ecosystem disturbance and climactic extremes.

Here, I review the role of consumers in seagrass ecosystems and investigate the ecological impacts of an extreme climactic event (marine heat wave) and subsequent widespread seagrass die-off in Shark Bay, Western Australia. Specifically, …

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

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 …

Gammaridean Amphipods As Bioindicators In Subtropical Seagrass Ecosystems, Jennifer L. Sweatman

FIU Electronic Theses and Dissertations

Anthropogenic disturbances are ubiquitous in coastal marine ecosystems. As such, more intensive monitoring efforts are necessary to conserve these valuable habitats. Bioindicators, organisms that predictably respond to changes in environmental variables, may be utilized in monitoring efforts to assess ecosystem functioning. To incorporate organisms into monitoring programs as bioindicators managers need to first understand the difference between the natural phenology of the focal organisms and their responses to different forms of anthropogenic disturbance.

To determine if gammaridean amphipods could be used as indicators of changes in environmental quality in sub-tropical seagrass ecosystems, I conducted spatial and temporal surveys of amphipod …

Disturbance Agents And Their Associated Effects On The Health Of Interior Douglas-Fir Forests In The Central Rocky Mountains, Andrew D. Giunta, Michael J. Jenkins, Elizabeth G. Hebertson, Allen S. Munson

Wildland Resources Faculty Publications

Interior Douglas-fir is a prevalent forest type throughout the central Rocky Mountains. Past management actions, specifically fire suppression, have led to an expansion of this forest type. Although Douglas-fir forests cover a broad geographic range, few studies have described the interactive effects of various disturbance agents on forest health conditions. In this paper, we review pertinent literature describing the roles, linkages, and mechanisms by which disturbances, including insect outbreaks, pathogens, fire, and other abiotic factors, affect the development, structure, and distribution of interior montane forests primarily comprised of Douglas-fir. We also discuss how these effects may influence important resource values …

Seagrass Community Change At Three High Risk Ports In The Great Barrier Reef World Heritage Area From 2005 To 2014, Celeste Venolia

Independent Study Project (ISP) Collection

Seagrass meadows are extremely valuable and dynamic ecosystems currently facing pressure from anthropogenic disturbances. Seagrass ecosystems are declining globally because of direct and indirect threats that shift environmental conditions controlling seagrass distribution. Seagrass species responses to disturbances vary based on a number of factors including life history strategy. The goal of this study was to map and analyze patterns of dominant seagrass species change at Cairns and Gladstone from 2005-2014 and Townsville from 2007-2014. This compilation data set was symbolized according to the life history strategy of the species. The major disturbances during this time period were physical damage from …

Responses Of Four Non-Tidal Forest Communities Of The Florida Everglades To Hurricane Impact Over 21 Years, Jeremy L. May

FIU Electronic Theses and Dissertations

The regular occurrence of hurricane-associated winds has been an important factor in shaping the structure and composition of the forest ecosystems of the Florida Everglades. Forest communities in the Everglades are adapted to hurricane disturbances, but increased frequency and/or intensity of hurricanes may lead to decline or even collapse of these communities. The overall objective of this project is to understand the patterns, pace, and mechanisms of the recovery process to Hurricane Andrew damage in four Everglade forest communities: pinelands, hardwood hammocks, bayhead tree islands, and cypress domes. This study combines long- and short-term field measurements and experimental garden studies …

Effects Of Researcher-Induced Disturbance On American Kestrels Breeding In Nest Boxes In Northwestern New Jersey, John Smallwood

Department of Biology Faculty Scholarship and Creative Works

Nest boxes for American Kestrels Falco sparverius may alleviate local nest site limitation, but there is concern that periodically opening nest boxes or handling adults may negatively affect nesting success. I monitored 536 kestrel breeding attempts ≥1 egg laid in about 100 nest boxes in northwestern New Jersey, 1995-2012. To study return rates, I opportunistically captured adults in nest boxes and marked them with U.S.G.S. leg bands and patagial tags. To examine possible effects of this disturbance, I compared nesting success ≥1 nestling surviving to banding age of marked and unmarked adults. Nesting success was 67% for 270 unmarked pairs, …

Influence Of Structural Disturbance On Stream Function And Macroinvertebrate Communities In Upper Coastal Plain Headwater Streams, Richard Andrew Biemiller

Theses and Dissertations--Entomology

Freshwater is a resource under threat due to anthropogenic actions. Stream restoration is a common method for mitigating disturbance. Inconsistent methodologies used for evaluating restorations have drawn criticism. Limited use of baseline data for guiding stream restoration activities is of particular concern. This study was developed to elucidate metrics that differentiate reference and disturbed sites in Upper Coastal Plain streams. This information could improve resource use and successes of restorations. Structural and functional variables were examined in 10 reference and 10 streams that meet the traditional definition of disturbance and would be restoration priorities. Disturbed streams were classified into two …

Forest Stand Structure And Primary Production In Relation To Ecosystem Development, Disturbance, And Canopy Composition, Cynthia M. Scheuermann

Theses and Dissertations

Temperate forests are complex ecosystems that sequester carbon (C) in biomass. C storage is related to ecosystem-scale forest structure, changing over succession, disturbance, and with community composition. We quantified ecosystem biological and physical structure in two forest chronosequences varying in disturbance intensity, and three late successional functional types to examine how multiple structural expressions relate to ecosystem C cycling. We quantified C cycling as wood net primary production (NPP), ecosystem structure as Simpson’s Index, and physical structure as leaf quantity (LAI) and arrangement (rugosity), examining how wood NPP-structure relates to light distribution and use-efficiency. Relationships between structural attributes of biodiversity, …