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Ecology and Evolutionary Biology

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University of Nebraska - Lincoln

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Articles 1 - 30 of 36

Full-Text Articles in Forest Sciences

Estimating Northern Spotted Owl (Strix Occidentalis Caurina) Pair Detection Probabilities Based On Call-Back Surveys Associated With Long-Term Mark-Recapture Studies, 1993–2018, Katie M. Dugger, Alan B. Franklin, Damon B. Lesmeister, Raymond J. Davis, J. David Wiens, Gary C. White, James D. Nichols, James E. Hines, Charles B. Yackulic, Carl J. Schwarz, Steven A. Ackers, L. Steven Andrews, Larissa L. Bailey, Robin Bown, Jesse Burgher, Kenneth P. Burnham, Peter C. Carlson, Tara Chestnut, Mary M. Conner, Krista E. Dilione, Eric D. Forsman, Scott A. Gremel, Keith A. Hamm, Dale R. Herter, J. Mark Higley, Rob B. Horn, Julianna M. Jenkins, William L. Kendall, David W. Lapmphear, Christopher Mccafferty, Trent L. Mcdonald, Janice A. Reid, Jeremy T. Rockweit, David C. Simon, Stan G. Sovern, James K. Swingle, Heather Wise Jan 2023

Estimating Northern Spotted Owl (Strix Occidentalis Caurina) Pair Detection Probabilities Based On Call-Back Surveys Associated With Long-Term Mark-Recapture Studies, 1993–2018, Katie M. Dugger, Alan B. Franklin, Damon B. Lesmeister, Raymond J. Davis, J. David Wiens, Gary C. White, James D. Nichols, James E. Hines, Charles B. Yackulic, Carl J. Schwarz, Steven A. Ackers, L. Steven Andrews, Larissa L. Bailey, Robin Bown, Jesse Burgher, Kenneth P. Burnham, Peter C. Carlson, Tara Chestnut, Mary M. Conner, Krista E. Dilione, Eric D. Forsman, Scott A. Gremel, Keith A. Hamm, Dale R. Herter, J. Mark Higley, Rob B. Horn, Julianna M. Jenkins, William L. Kendall, David W. Lapmphear, Christopher Mccafferty, Trent L. Mcdonald, Janice A. Reid, Jeremy T. Rockweit, David C. Simon, Stan G. Sovern, James K. Swingle, Heather Wise

United States Department of Agriculture Wildlife Services: Staff Publications

The northern spotted owl (Strix occidentalis caurina; hereinafter NSO) was listed as “threatened” under the Endangered Species Act in 1990 and population declines have continued since that listing. Given the species’ protected status, any proposed activities on Federal lands that might impact NSO require consultation with U.S. Fish and Wildlife Service and part of that consultation often includes surveys to determine presence and occupancy status of the species in the proposed activity area. The objective of this report is to present study-area specific estimates of the probability of detection for NSO pairs from twelve 2-week seasonal survey periods …


Invasive Plants Watch List: 2022, Allison Zach Jan 2022

Invasive Plants Watch List: 2022, Allison Zach

Nebraska Invasive Species Program

The purpose of the weed watch list is to collect data on the distribution of invasive plants found in various Nebraska counties. Counties were divided up into ‘ecoregions’ based on the Nebraska Game & Parks Commission’s Legacy Plan (map of regions below). The plants in the watch list have been identified based on their invasiveness in surrounding states and their increasing range in Nebraska. Data collected on watch list plant species distribution has been used to support the listing or delisting of noxious weeds. Plant species in the weed watch list are categorized based on early detection and rapid response …


Soil Microbial Community Dynamics In Response To Prescribed Extreme Fires Following Juniperus Virginiana Invasion In The Loess Canyons Of Nebraska, Julie A. Fowler Dec 2021

Soil Microbial Community Dynamics In Response To Prescribed Extreme Fires Following Juniperus Virginiana Invasion In The Loess Canyons Of Nebraska, Julie A. Fowler

School of Natural Resources: Dissertations, Theses, and Student Research

In Nebraska and other regions of the Great Plains, the conifer Juniperus virginiana (eastern redcedar) is converting grasslands to dense woodlands. This is driven by the interacting drivers of fire suppression, altered grazing regimes, climate change and other anthropogenic factors, impacting the provisioning of ecosystem services. This vegetation state transition modifies water resource regulation and biogeochemical cycles leading to altered edaphic properties including soil microbial community composition. To restore these grasslands and control J. virginiana spread, prescribed extreme burns are implemented as a management tool through local prescribed burn associations. We hypothesized that the alternative state transition to dense J. …


Seed Rain–Successional Feedbacks In Wet Tropical Forests, Nohemi Huanca Nuñez, Robin L. Chazdon, Sabrina E. Russo Apr 2021

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 …


Extreme Fire As A Management Tool To Combat Regime Shifts In The Range Of The Endangered American Burying Beetle, Alison K. Ludwig, Daniel R. Uden, Dirac Twidwell Apr 2020

Extreme Fire As A Management Tool To Combat Regime Shifts In The Range Of The Endangered American Burying Beetle, Alison K. Ludwig, Daniel R. Uden, Dirac Twidwell

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

This study is focused on the population of federally-endangered American burying beetles in south-central Nebraska. It is focused on changes in land cover over time and at several levels of spatial scale, and how management efforts are impacting both the beetle and a changing landscape. Our findings are applicable to a large portion of the Great Plains, which is undergoing the same shift from grassland to woodland, and to areas where the beetle is still found.


Testing The Competition-Colonization Trade-Off And Its Correlations With Functional Trait Variations Among Subtropical Tree Species, Yue Bin, Guojun Lin, Sabrina E. Russo, Zhongliang Huang, Yong Shen, Honglin Cao, Juyu Lian, Wanhui Ye Jan 2019

Testing The Competition-Colonization Trade-Off And Its Correlations With Functional Trait Variations Among Subtropical Tree Species, Yue Bin, Guojun Lin, Sabrina E. Russo, Zhongliang Huang, Yong Shen, Honglin Cao, Juyu Lian, Wanhui Ye

School of Biological Sciences: Faculty Publications

The competition-colonization trade-off, by which species can partition spatial niches, is a potentially important mechanism allowing the maintenance of species diversity in plant communities. We examined whether there was evidence for this trade-off among tree species in a subtropical forest and how it correlated with eight functional traits. We developed and estimated a metric for colonization ability that incorporates both fecundity and seed dispersal based on seed trap data and the sizes and distributions of adult trees. Competitive ability was estimated as survival probability under high crowding conditions based on neighborhood models. Although we found no significant relationship between colonization …


Nebraska Invasive Plants Field Guide, Nebraska Invasive Species Program Jan 2018

Nebraska Invasive Plants Field Guide, Nebraska Invasive Species Program

Nebraska Invasive Species Program

Invasive species are plants, animals or pathogens that are non-native to an ecosystem. They cause harm to the economy, environment or human health. They negatively affect native species and ecosystems and interfere with outdoor recreation opportunities. This guide identifies federal and state-listed noxious weeds. Federal noxious weeds are regulated by the U.S. Department of Agriculture; State noxious weeds are regulated by the Nebraska Department of Agriculture, Animal and Plant Health Protection, Noxious Weed Program. Aquatic invasive species are listed and regulated by Nebraska Game and Parks Commission.

ABSINTH WORMWOOD • AMUR HONEYSUCKLE • AUTUMN OLIVE • BRITTLE NAIAD • CALLERY …


Review Of Bird Brain: An Exploration Of Avian Intelligence By Nathan Emery, Alan B. Bond Jan 2017

Review Of Bird Brain: An Exploration Of Avian Intelligence By Nathan Emery, Alan B. Bond

Avian Cognition Papers

Over the past 30 years, the study of bird behavior has been completely transformed by the ongoing revolution in cognitive psychology, opening up wholly new perspectives on the mental processes underlying such areas as foraging decisions, social intelligence, problem solving, memory encoding, and communication. Although these studies have contributed to a number of recent popular books, until now there has been no attempt to integrate avian cognition and recent findings in avian neuroanatomy and endocrinology into a single account that is attractive and accessible to a general readership. It is a steep challenge, but Nathan Emery has undertaken it in …


Carbon Storage Potential Of Windbreaks On Agricultural Lands Of The Continental United States, William Ballesteros Possu Jul 2015

Carbon Storage Potential Of Windbreaks On Agricultural Lands Of The Continental United States, William Ballesteros Possu

School of Natural Resources: Dissertations, Theses, and Student Research

Agricultural production systems face major challenges under climate change scenarios in terms of expected negative impacts on productivity and persistence of the crops. Greenhouse gases from agriculture continue to rise although not as fast as from other fossil fuel-based human activities. Windbreaks perform several ecosystems functions that improve the local and regional capacity of crop systems to increase yields and offer environmental services by minimizing the negative effects of extreme weather events. Windbreaks also represent an important means of mitigating greenhouse gas emissions. This is predominantly accomplished by the windbreak trees storing carbon (C) in their above and belowground woody …


Historical Common Names Of Great Plains Plants, With Scientific Names Index. Volume Ii: Scientific Names Index, Elaine Nowick Mar 2015

Historical Common Names Of Great Plains Plants, With Scientific Names Index. Volume Ii: Scientific Names Index, Elaine Nowick

Zea E-Books Collection

Containing thousands of entries of both vernacular and scientific names of Great Plains plants, the literature that informs this exhaustive listing spans nearly 300 years. Author Elaine Nowick has drawn from sources as diverse as Linnaeus, Lewis and Clark, and local university extension publications to compile the gamut of practical, and often fanciful, common plant names used over the years. Each common name is accompanied by a definitive scientific name with references and authority information. Interspersed with scientifically-correct botanical line drawings, the entries are written in standard ICBN format, making this a useful volume for scholars as well as lay …


Soils Of Temperate Rainforests Of The North American Pacific Coast, Dunbar N. Carpenter, James G. Bockheim, Paul F. Reich Jan 2014

Soils Of Temperate Rainforests Of The North American Pacific Coast, Dunbar N. Carpenter, James G. Bockheim, Paul F. Reich

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Temperate rainforests have high conservation and natural resource value, but the soils of this bioregion have not previously been studied as a unit. Here we examine the soils of North America's Pacific coastal temperate rainforests, utilizing databases from the United States Natural Resources Conservation Service and the Canadian Centre for Land and Biological Resources Research to (i) identify the soil taxa, (ii) evaluate the soil properties, and (iii) compare soils in temperate and tropical rainforests. There are strong climate gradientswithin these temperate rainforests,with the mean temperature declining from 11.7 °C to 6.1 °C and the mean annual precipitation increasing from …


An Illustrated Id Guide To The Crayfishes Found In Nebraska Native And Non-Native, Steve Schainost Jan 2014

An Illustrated Id Guide To The Crayfishes Found In Nebraska Native And Non-Native, Steve Schainost

Nebraska Invasive Species Program

There are five crayfishes native to Nebraska. These are:

Orconectes immunis (papershell crayfish)

Orconectes virilis (northern crayfish)

Orconectes neglectus neglectus (ringed crayfish)

Cambarus diogenes (Devil crayfish)

Procambarus gracilis (prairie crayfish)

Three additional non-native crayfishes have also been found here:

Orconectes rusticus (rusty crayfish) [bait tanks and established in two ponds in Omaha]

Procambarus clarkii (red swamp crayfish) [bait tanks]

Procambarus acutus (White River crayfish) [bait tanks]

I will attempt here to provide a photographic guide to field identification, one species per page.


Quantitative Analysis Of Woodpecker Habitat Using High-Resolution Airborne Lidar Estimates Of Forest Structure And Composition, James E. Garabedian, Robert Mcgaughey, Stephen E. Reutebuch, Bernard R. Parresol, John C. Kilgo, Christopher E. Moorman, M. Nils Peterson Jan 2014

Quantitative Analysis Of Woodpecker Habitat Using High-Resolution Airborne Lidar Estimates Of Forest Structure And Composition, James E. Garabedian, Robert Mcgaughey, Stephen E. Reutebuch, Bernard R. Parresol, John C. Kilgo, Christopher E. Moorman, M. Nils Peterson

United States Department of Agriculture, Forest Service / University of Nebraska-Lincoln: Faculty Publications

Light detection and ranging (LiDAR) technology has the potential to radically alter theway researchers and managers collect data onwildlife–habitat relationships. To date, the technology has fostered several novel approaches to characterizing avian habitat, but has been limited by the lack of detailed LiDAR-habitat attributes relevant to species across a continuum of spatial grain sizes and habitat requirements. We demonstrate a novel three-step approach for using LiDAR data to evaluate habitat based on multiple habitat attributes and accounting for their influence at multiple grain sizes using federally endangered red-cockaded woodpecker (RCW; Picoides borealis) foraging habitat data fromthe Savannah River Site (SRS) …


Drought-Induced Woody Plant Mortality In An Encroached Semi-Arid Savanna Depends On Topoedaphic Factors And Land Management, Dirac L. Twidwell Jr, Carissa L. Wonkka, Charles A. Taylor, Chris B. Zou, Jeremiah J. Twidwell, William E. Rogers Jan 2014

Drought-Induced Woody Plant Mortality In An Encroached Semi-Arid Savanna Depends On Topoedaphic Factors And Land Management, Dirac L. Twidwell Jr, Carissa L. Wonkka, Charles A. Taylor, Chris B. Zou, Jeremiah J. Twidwell, William E. Rogers

Department of Agronomy and Horticulture: Faculty Publications

Questions: How do recent patterns of drought-induced woody plant mortality in Texas semi-arid savanna compare to the extended drought of the 1950s? Does the relative composition of the woody plant community shift ubiquitously across the landscape following woody plant mortality and dieback or are shifts dependent on differences among species, soils, land use and plant demography?

Location: Texas Agrilife Research Station, Sonora, Texas, USA (30.1° N 100.3° W).

Methods: Following an exceptional drought from 1951 to 1957, a study was conducted to quantify rates of mortality for various woody plant species. In 2011, we repeated this study within three long-term …


Estudios Científicos En El Estado De Hidalgo Y Zonas Aledañas, Volumen Ii, Griselda Pulido-Flores, Scott Monks Jun 2013

Estudios Científicos En El Estado De Hidalgo Y Zonas Aledañas, Volumen Ii, Griselda Pulido-Flores, Scott Monks

Zea E-Books Collection

Los 16 capítulos que conforman este libro son una contribución al conocimiento de la biodiversidad y conservación de los recursos naturales en el estado de Hidalgo, México.

Se aborda el derecho de propiedad intelectual en la biodiversidad, citando algunos ejemplos de México. Así mismo, se presenta un estudio de la biodiversidad y distribución de la herpetofauna en cuatro tipos de vegetación. Desde el punto de vista de la helmintología se presentan dos estudios de los helmintos parásitos de vertebrados silvestres; con nuevos registros de hospederos y localidades de algunas especies de helmintos para Hidalgo. También, se aborda el uso de …


Changing Room Cues Reduces The Effects Of Proactive Interference In Clark’S Nutcrackers, Nucifraga Columbiana, Jody L. Lewis, Alan C. Kamil, Kate E. Webbink Jan 2013

Changing Room Cues Reduces The Effects Of Proactive Interference In Clark’S Nutcrackers, Nucifraga Columbiana, Jody L. Lewis, Alan C. Kamil, Kate E. Webbink

Avian Cognition Papers

To determine what factors are important for minimizing interference effects in spatial memory, Clark’s Nutcrackers, Nucifraga columbiana were tested for their spatial memory for two serial lists of locations per day. In this experiment two unique landmark sets were either different between List 1 and List 2 or the same. We found that Nutcrackers were most susceptible to interference when the landmark sets were the same. This study suggests that repeatedly testing animal memory in the same room, with the same cues, can hamper recall due to interference.


Differences In Relative Hippocampus Volume And Number Of Hippocampus Neurons Among Five Corvid Species, Kristy L. Gould, Karl E. Gilbertson, Andrew J. Hrvol, Joseph C. Nelson, Abigail L. Seyfer, Rose M. Brantner, Alan C. Kamil Jan 2013

Differences In Relative Hippocampus Volume And Number Of Hippocampus Neurons Among Five Corvid Species, Kristy L. Gould, Karl E. Gilbertson, Andrew J. Hrvol, Joseph C. Nelson, Abigail L. Seyfer, Rose M. Brantner, Alan C. Kamil

Avian Cognition Papers

The relative size of the avian hippocampus (Hp) has been shown to be related to spatial memory and food storing in two avian families, the parids and corvids. Basil et al. [Brain Behav Evol 1996;47: 156-164] examined North American food-storing birds in the corvid family and found that Clark’s nutcrackers had a larger relative Hp than pinyon jays and Western scrub jays. These results correlated with the nutcracker’s better performance on most spatial memory tasks and their strong reliance on stored food in the wild. However, Pravosudov and de Kort [Brain Behav Evol 67 (2006), 1-9] raised questions …


Refining Thresholds In Coupled Fire–Vegetation Models To Improve Management Of Encroaching Woody Plants In Grasslands, Dirac L. Twidwell Jr, Samuel D. Fuhlendorf, Charles A. Taylor Jr, William E. Rogers Jan 2013

Refining Thresholds In Coupled Fire–Vegetation Models To Improve Management Of Encroaching Woody Plants In Grasslands, Dirac L. Twidwell Jr, Samuel D. Fuhlendorf, Charles A. Taylor Jr, William E. Rogers

Department of Agronomy and Horticulture: Faculty Publications

1. Restoration priorities are typically established without quantitative information on how to overcome the thresholds that preclude successful restoration of desirable ecosystem properties and services. We seek to demonstrate that quantifying ecological thresholds and incorporating them into management-oriented frameworks provide a more comprehensive perspective on how the threshold concept can be applied to achieve restoration goals.

2. As an example, restoration actions have been largely unsuccessful when based on prevailing ecological knowledge of fire-based thresholds in nonresprouting Juniperus woodland. We build on previous threshold-based research and link well-established models from applied fire physics with a widely applied ecological positive feedback …


Do Clark’S Nutcrackers Demonstrate What-Where-When Memory On A Cache-Recovery Task?, Kristy L. Gould, Amy J. Ort, Alan C. Kamil Jan 2012

Do Clark’S Nutcrackers Demonstrate What-Where-When Memory On A Cache-Recovery Task?, Kristy L. Gould, Amy J. Ort, Alan C. Kamil

Avian Cognition Papers

What-where-when (WWW) memory during cache recovery was investigated in six Clark’s nutcrackers. During caching, both red- and blue-colored pine seeds were cached by the birds in holes filled with sand. Either a short (3 day) retention interval (RI) or a long (9 day) RI was followed by a recovery session during which caches were replaced with either a single seed or wooden bead depending upon the color of the cache and length of the retention interval. Knowledge of what was in the cache (seed or bead), where it was located, and when the cache had been made (3 or 9 …


Bacterial Community Structure Of Contrasting Soils Underlying Bornean Rain Forests: Inferences From Microarray And Next-Generation Sequencing Methods, Sabrina E. Russo, Ryan Legge, Karrie A. Weber, Eoin L. Brodie, Katherine C. Goldfarb, Andrew K. Benson, Sylvester Tan Jan 2012

Bacterial Community Structure Of Contrasting Soils Underlying Bornean Rain Forests: Inferences From Microarray And Next-Generation Sequencing Methods, Sabrina E. Russo, Ryan Legge, Karrie A. Weber, Eoin L. Brodie, Katherine C. Goldfarb, Andrew K. Benson, Sylvester Tan

School of Biological Sciences: Faculty Publications

Soil microbial diversity is vast, and we lack even basic understanding of how this diversity is distributed ecologically. Using pyrosequencing and microarray methods, we quantified the structure of bacterial communities in two contrasting soils underlying Bornean rain forest (clay and sandy loam) that differ markedly in soil properties, aboveground tree flora, and leaf litter decomposition rates. We found significant soil-related taxonomic and phylogenetic differences between communities that, due to their proximity, are independent of climate. Bacterial communities showed distinct compositional and taxon-abundance distributions that were significantly correlated with the structure of the overlying tree community. Richness of bacteria was greater …


Conservation Cuantitativa De Los Vertebrados, Michael J. Conroy, John P. Carroll, Juan Carlos Senar, Jeffrey J. Thompson Jan 2011

Conservation Cuantitativa De Los Vertebrados, Michael J. Conroy, John P. Carroll, Juan Carlos Senar, Jeffrey J. Thompson

School of Natural Resources: Faculty Publications

Este libro es destinado para el uso por biólogos del campo y otras personas, incluso biólogos de campo en el futuro que podrían estar en un curso de la universidad y trabajando en estudios y conservación de animales. Nuestro objetivo es que los biólogos usen este libro como (haciendo apología a nuestro colega Evan Cooch) una ´´introducción suave´´ al campo de la ecología cuantitativa. Esperamos convencer a los lectores que los métodos y aproximaciones del libro no son solo para los matemáticos, estadísticos y programadores de computadoras, sino que de hecho son herramientas esenciales para practicar la conservación en el …


Variations In Stomatal Traits Of 14 Bornean Tree Species Growing On Soils With Different Moisture Contents In Lambir Hills National Park, Whitney Logan Cannon Oct 2008

Variations In Stomatal Traits Of 14 Bornean Tree Species Growing On Soils With Different Moisture Contents In Lambir Hills National Park, Whitney Logan Cannon

Department of Environmental Studies: Undergraduate Student Theses

The goal of this study was to look at variations in stomatal traits of tree species on soils with different moisture contents and fertility at Lambir Hills National Park. Stomates are important structures on the surface of leaves that mediate conduction of moisture and gassesin and out of the leaf. If stomatalt raits are important for regulation, then there should be variation in stomatal traits in regards to their soil specialization. The 14 Borneant ree speciess ampledi ncluded6 sandyl oam specialists6, clay specialistsa nd 2 generalistsfo und growing with equald istributionso n both sandyl oam and clay. Confocal microscopy was …


Effects Of Gregariousness, Conspicuousness, And Novelty On Blue Jay (Cyanocitta Cristata) Learned Avoidance And Stimulus Generalization Of Unpalatable Prey, Joyce M. Dykema Apr 2008

Effects Of Gregariousness, Conspicuousness, And Novelty On Blue Jay (Cyanocitta Cristata) Learned Avoidance And Stimulus Generalization Of Unpalatable Prey, Joyce M. Dykema

Avian Cognition Papers

I examined a variety of factors hypothesized to be important in the evolution and maintenance of aposematism. Aposematism occurs when prey individuals advertise their toxic or otherwise aversive nature to potential predators via evolved conspicuous signals. I conducted three experiments in which blue jays (Cyanocitta cristata) were allowed to search a printed grayscale pixilated background for grayscale pixilated moths in an open room. I manipulated moth appearance and food reward, and recorded jay predation on the varying moth stimuli. In my first experiment, I repeated Alatalo & Mappes’ (1996) study examining the effects of prey gregariousness, or grouping, …


Bats In A Human-Made Forest Of Central Nebraska, Keith Geluso Mar 2006

Bats In A Human-Made Forest Of Central Nebraska, Keith Geluso

The Prairie Naturalist

Increases in wooded habitats have led to expansion in distributions of woodland mammals in the Great Plains. Herein, I report on the occurrence of bats in a human-made forest consisting of over 8,000 hectares in central Nebraska. The forest consisted of monocultures of ponderosa pine (Pinus ponderosa), eastern red cedar (Juniperus virginiana), and jack pine (Pinus banksiana). Individuals of the eastern red bat (Lasiurus borealis) and hoary bat (L. cinereus) were captured in coniferous plantations during summer, and females of both species bore and raised young in the area. …


K-Means Clustering With Multiresolution Peak Detection, Guanshan Yu, Leen-Kiat Soh, Alan B. Bond May 2005

K-Means Clustering With Multiresolution Peak Detection, Guanshan Yu, Leen-Kiat Soh, Alan B. Bond

Avian Cognition Papers

Clustering is a practical data mining approach of pattern detection. Because of the sensitivity of initial conditions, k-means clustering often suffers from low clustering performance. We present a procedure to refine initial conditions of k-means clustering by analyzing density distributions of a data set before estimating the number of clusters k necessary for the data set, as well as the positions of the initial centroids of the clusters. We demonstrate that this approach indeed improves the accuracy and performance of k-means clustering measured by average intra to interclustering error ratio. This method is applied to the virtual ecology project to …


Determining Differences In The Spatial Distribution Of Forest Structure On The Kaibab Plateau: Implications For Forest Management And The Northern Goshawk, Ryan S. Miller Apr 2001

Determining Differences In The Spatial Distribution Of Forest Structure On The Kaibab Plateau: Implications For Forest Management And The Northern Goshawk, Ryan S. Miller

Other Publications in Wildlife Management

The Kaibab Plateau, in North Central Arizona, has undergone extensive change in the last 100 years due to land management practices such as logging, road building, and fire suppression. The northern goshawk (Accipiter gentilis) has been a center of controversy, due to the potential effects of silvicultural practices on goshawk breeding habitat (Reynolds-1983, Bloom et al 1986, Kennedy 1989, Crocker-Bedford 1990). Current and past research efforts on the Kaibab Plateau have mapped Goshawk nesting territories and temporal change in nesting behavior and success. However, these research efforts have not determined how long-term spatial changes in land-use activities that have influenced …


The Effect Of Proximity On Landmark Use In Clark’S Nutcrackers, Kristy L. Gould-Beierle, Alan Kamil Jan 1999

The Effect Of Proximity On Landmark Use In Clark’S Nutcrackers, Kristy L. Gould-Beierle, Alan Kamil

Avian Cognition Papers

Clark’s nutcrackers, Nucifraga columbiana, store thousands of pine seeds during the autumn and retrieve them throughout the winter. It has been shown that these birds are able to use visual cues to relocate hidden food in the laboratory. In this set of experiments, we trained three groups of Clark’s nutcrackers to find a hidden food goal that was placed in the same spatial location relative to the testing room. During training, the location of two local cues in relation to the goal differed between the three groups. Group 1 learned the task with the cues closest to the goal, group …


Patterns Of Movement And Orientation During Caching And Recovery By Clark’S Nutcrackers, Nucifraga Columbiana, Alan Kamil, Russell P. Balda, Sally Good Jan 1999

Patterns Of Movement And Orientation During Caching And Recovery By Clark’S Nutcrackers, Nucifraga Columbiana, Alan Kamil, Russell P. Balda, Sally Good

Avian Cognition Papers

Clark’s nutcrackers regularly store large numbers of pine seeds and remember the locations of the cached seeds. Although they are very accurate, they do make some errors during recovery. In an attempt to determine whether any behaviours during caching predicted the occurrence of errors during recovery, we videotaped Clark’s nutcrackers while they cached and recovered seeds under laboratory conditions. We used the videotapes to develop complete, quantitative descriptions of caching and recovery behaviour, with an emphasis on body orientation and directions of movement. During caching, the birds showed the greatest change in their orientation and direction following cache creation. During …


How Do They, Indeed? A Reply To Biegler Et Al., Alan Kamil, Juli E. Jones Jan 1999

How Do They, Indeed? A Reply To Biegler Et Al., Alan Kamil, Juli E. Jones

Avian Cognition Papers

We trained Clark’s nutcrackers, Nucifraga columbiana, to search halfway between two landmarks while varying the distance between the landmarks (Kamil & Jones 1997). We found that the birds learned the problem readily and generalized to novel interlandmark distances within the range of distances used during training. Unlike some other studies in which responses to proportional distance were obtained (e.g. O’Keefe & Burgess 1996; Tommasi et al. 1997), the nutcrackers showed very precise search and maintained this precision during the transfer test. The distributions of digging locations around the central position were concentrated within ±1–2 cm of the central location …


Management Of Red Squirrel Feeding Damage To Lodgepole Pine By Stand Density Manipulation And Diversionary Food, Thomas P. Sullivan Jan 1998

Management Of Red Squirrel Feeding Damage To Lodgepole Pine By Stand Density Manipulation And Diversionary Food, Thomas P. Sullivan

Vertebrate Pest Conference Proceedings: 18th (1998)

The red squirrel (Tamiasciurus hudsonicus) feeds on the vascular tissues of sapling lodgepole pine (Pinus contorta) during spring periods in forests of interior British Columbia and Alberta, Canada. This damage may lead to mortality and reduced growth of crop trees in managed stands. Manipulation of stand density by pre-commercial thinning to densities < 1,000 stems/ha is an effective method to lower squirrel populations and feeding damage. Lowering stand density enhances the growth of crop trees, and understory herbs and shrubs as wildlife habitat, while protecting trees from squirrel feeding. This approach has been successful in several forest ecological zones. An alternative management tool is provision of diversionary food (sunflower seed) for those stands susceptible to feeding damage, and where stand thinning has already been completed. Diversionary food can be applied aerially and is very cost effective for protecting managed stands. These techniques may be used to maintain or even enhance species diversity of small mammal communities in those forest stands requiring protection.