Open Access. Powered by Scholars. Published by Universities.®

Population Biology Commons

Open Access. Powered by Scholars. Published by Universities.®

Dispersal

Discipline
Institution
Publication Year
Publication
Publication Type

Articles 1 - 25 of 25

Full-Text Articles in Population Biology

Predicting Dispersal And Conflict Risk For Wolf Recolonization In Colorado, Mark A. Ditmer, George Wittemyer, Katherine A. Zeller, Stewart W. Breck, Robert J. Fletcher Jr., Kevin R. Crooks Jan 2023

Predicting Dispersal And Conflict Risk For Wolf Recolonization In Colorado, Mark A. Ditmer, George Wittemyer, Katherine A. Zeller, Stewart W. Breck, Robert J. Fletcher Jr., Kevin R. Crooks

USDA Wildlife Services: Staff Publications

1. The colonization of suitable yet unoccupied habitat due to natural dispersal or human introduction can benefit recovery of threatened species. Predicting habitat suitability and conflict potential of colonization areas can facilitate conservation planning.

2. Planning for reintroduction of gray wolves (Canis lupus) to the United States state of Colorado is underway. Assessing which occupancy sites minimize the likelihood of human-wolf conflict during dispersal events and seasonal movements is critical to the success of this initiative.

3. We used a spatial absorbing Markov chain (SAMC) framework, which extends random walk theory and probabilistically accounts for both movement behavior …


Translocating Wild California Valley Quail To Texas: An Evaluation Of Survival, Dispersal, Tracking Efficacy, And Roost Preference, Garrett Rushing, Jordan T. Conley, Jeffrey G. Whitt, Kelly S. Reyna Sep 2022

Translocating Wild California Valley Quail To Texas: An Evaluation Of Survival, Dispersal, Tracking Efficacy, And Roost Preference, Garrett Rushing, Jordan T. Conley, Jeffrey G. Whitt, Kelly S. Reyna

National Quail Symposium Proceedings

Quail translocations are becoming increasingly popular in regions of suitable habitat where local quail populations have declined. In northeastern Texas, USA, northern bobwhite (Colinus virginianus) populations have drastically declined for over a century and have reached undetectable levels in many areas. As a result, the number of quail hunters and quail conservation funding have also declined. California valley quail (Callipepla californica; hereafter, valley quail) have increased across their range and have been translocated to many states and countries. Thus, the goal of this study was to determine whether translocating wild valley quail to Texas was feasible, …


The Southern Flying Squirrel (Glaucomys Volans) In Lincoln, Nebraska, Melissa J. Panella, Shaun M. Dunn, Thomas E. Labedz, Hugh H. Genoways Sep 2022

The Southern Flying Squirrel (Glaucomys Volans) In Lincoln, Nebraska, Melissa J. Panella, Shaun M. Dunn, Thomas E. Labedz, Hugh H. Genoways

Transactions of the Nebraska Academy of Sciences and Affiliated Societies

The southern flying squirrel (Glaucomys volans) is considered a species of greatest conservation need in Nebraska and listed as threatened in the state. Historically, the geographic range of the southern flying squirrel in Nebraska has been restricted to five eastern counties from a northern suburb of Omaha, Douglas Co., southward in the four counties of Sarpy, Otoe, Nemaha, and Richardson, all bordering the Missouri River on the east. In late November of 2018, a resident of Lincoln, Lancaster Co., Nebraska, contacted the Nebraska Game and Parks Commission about an animal found dead in his yard. This animal proved …


The Impact Of Long-Term Artificial Removal Experiment And Natural Local Extinctions On The Genetics Of An Alpine Butterfly, Keon Young Park Jun 2022

The Impact Of Long-Term Artificial Removal Experiment And Natural Local Extinctions On The Genetics Of An Alpine Butterfly, Keon Young Park

Electronic Thesis and Dissertation Repository

In the current age of widespread anthropogenic effects across the globe, organisms are vulnerable to habitat fragmentation and localized decline in population more than ever before. Therefore, insight into metapopulation-level dynamics and the genetic basis of inter-patch dispersal is key to understanding the regional persistence of a species in the face of potential localized extinction or population bottleneck. In this study I used samples from a previously conducted localized long-term population removal experiment to investigate the effects of an extended population reductions on the genetic structure of a local population, and to explore the genetic basis of dispersal and recolonization …


Optimizing Management Of Invasions In An Uncertain World Using Dynamic Spatial Models, Kim M. Pepin, Amy J. Davis, Rebecca S. Epanchin-Niell, Andrew M. Gormley, Joslin L. Moore, Timothy J. Smyser, H. Bradley Shaffer, William L. Kendall, Katriona Shea, Michael C. Runge, Sophie Mckee Feb 2022

Optimizing Management Of Invasions In An Uncertain World Using Dynamic Spatial Models, Kim M. Pepin, Amy J. Davis, Rebecca S. Epanchin-Niell, Andrew M. Gormley, Joslin L. Moore, Timothy J. Smyser, H. Bradley Shaffer, William L. Kendall, Katriona Shea, Michael C. Runge, Sophie Mckee

USDA Wildlife Services: Staff Publications

Dispersal drives invasion dynamics of nonnative species and pathogens. Applying knowledge of dispersal to optimize the management of invasions can mean the difference between a failed and a successful control program and dramatically improve the return on investment of control efforts. A common approach to identifying optimal management solutions for invasions is to optimize dynamic spatial models that incorporate dispersal. Optimizing these spatial models can be very challenging because the interaction of time, space, and uncertainty rapidly amplifies the number of dimensions being considered. Addressing such problems requires advances in and the integration of techniques from multiple fields, including ecology, …


Subspecific Designation Of The U.S.A. Interior Highlands Population Of Argynnis (Speyeria) Diana (Cramer, 1777) (Nymphalidae: Heliconiinae: Argynnini: Argynnina), Harry Pavulaan Nov 2021

Subspecific Designation Of The U.S.A. Interior Highlands Population Of Argynnis (Speyeria) Diana (Cramer, 1777) (Nymphalidae: Heliconiinae: Argynnini: Argynnina), Harry Pavulaan

The Taxonomic Report of the International Lepidoptera Survey

Subspecific designation is designated for the North American Interior Highlands population of Argynnis diana, based on four factors: mtDNA haplotype differences from nominotypical A. diana of the Appalachian Mountains; wing shape difference in the males between both regions; wing size of the adults; and tendency for females of the Interior Highlands to show tan coloration in the submarginal row of rectangular spots of the subapical region of the dorsal forewings.


Dispersal And Land Cover Contribute To Pseudorabies Virus Exposure In Invasive Wild Pigs, Felipe A. Hernandez, Amanda N. Carr, Michael P. Milleson, Hunter R. Merrill, Michael L. Avery, Brandon M. Parker, Cortney L. Pylant, James D. Austin, Samantha M. Wisely Jan 2021

Dispersal And Land Cover Contribute To Pseudorabies Virus Exposure In Invasive Wild Pigs, Felipe A. Hernandez, Amanda N. Carr, Michael P. Milleson, Hunter R. Merrill, Michael L. Avery, Brandon M. Parker, Cortney L. Pylant, James D. Austin, Samantha M. Wisely

USDA Wildlife Services: Staff Publications

We investigated the landscape epidemiology of a globally distributed mammal, the wild pig (Sus scrofa), in Florida (U.S.), where it is considered an invasive species and reservoir to pathogens that impact the health of people, domestic animals, and wildlife. Specifically, we tested the hypothesis that two commonly cited factors in disease transmission, connectivity among populations and abundant resources, would increase the likelihood of exposure to both pseudorabies virus (PrV) and Brucella spp. (bacterial agent of brucellosis) in wild pigs across the Kissimmee Valley of Florida. Using DNA from 348 wild pigs and sera from 320 individuals at 24 sites, we …


Incorporating Early Life History And Recruitment In Analysis Of Population Dynamics Of Wetland Fishes, John Vincent Gatto Oct 2019

Incorporating Early Life History And Recruitment In Analysis Of Population Dynamics Of Wetland Fishes, John Vincent Gatto

FIU Electronic Theses and Dissertations

Hydrological variation is believed to be the major abiotic factor influencing fish recruitment in floodplain ecosystems. However, past studies fail to address the impact of hydrology on the three major drivers of recruitment: age-specific growth and mortality, and dispersal. I examined long-term recruitment dynamics for six fish species inhabiting the Everglades by addressing the impact of hydrology on these important characteristics. I then linked these changes to annual fluctuations in population size.

Before interpreting time-series data on recruitment, I evaluated the impact of size-selective bias from sampling gear on our interpretation of hydrological drivers of recruitment. Analyses revealed that individuals …


Survival, Fidelity, And Dispersal Of Double-Crested Cormorants On Two Lake Michigan Islands, Christopher R. Ayers, Katie C. Hanson-Dorr, Ken Stromborg, Todd W. Arnold, Jacob S. Ivan, Brian S. Dorr Jun 2019

Survival, Fidelity, And Dispersal Of Double-Crested Cormorants On Two Lake Michigan Islands, Christopher R. Ayers, Katie C. Hanson-Dorr, Ken Stromborg, Todd W. Arnold, Jacob S. Ivan, Brian S. Dorr

USDA Wildlife Services: Staff Publications

Colony fidelity and dispersal can have important consequences on the population dynamics of colonial-nesting birds. We studied survival and inter-colony movements of Double-crested Cormorants (Phalacrocorax auritus; cormorants) nesting at Spider and Pilot islands, located 9 km apart in western Lake Michigan, during 2008–2014. We used live resighting and dead recovery data from both colonies, plus dead recoveries from throughout North America, in a multistate live and dead encounter model to estimate annual survival, inter-colony movements, plus temporary and permanent emigration to unmonitored sites. Annual survival averaged 0.37 (annual process variation, ˆ = 0.07) for hatch-year, 0.78 (ˆ= 0.08) for secondyear, …


Integrating Species Traits Into Species Pools, Marko J. Spasojevic, Christopher P. Catano, Joseph A. Lamanna Jun 2018

Integrating Species Traits Into Species Pools, Marko J. Spasojevic, Christopher P. Catano, Joseph A. Lamanna

Biology Faculty Publications & Presentations

Despite decades of research on the species‐pool concept and the recent explosion of interest in trait‐based frameworks in ecology and biogeography, surprisingly little is known about how spatial and temporal changes in species‐pool functional diversity (SPFD) influence biodiversity and the processes underlying community assembly. Current trait‐based frameworks focus primarily on community assembly from a static regional species pool, without considering how spatial or temporal variation in SPFD alters the relative importance of deterministic and stochastic assembly processes. Likewise, species‐pool concepts primarily focus on how the number of species in the species pool influences local biodiversity. However, species pools with similar …


Rapid Range Expansion Of The Brazilian Free-Tailed Bat In The Southeastern United States, 2008-2016, Gary F. Mccracken, Riley F. Bernard, Melquisidec Gamba-Rios, Randy Wolfe, Jennifer J. Krauel, Devin N. Jones, Amy L. Russell, Veronica A. Brown Apr 2018

Rapid Range Expansion Of The Brazilian Free-Tailed Bat In The Southeastern United States, 2008-2016, Gary F. Mccracken, Riley F. Bernard, Melquisidec Gamba-Rios, Randy Wolfe, Jennifer J. Krauel, Devin N. Jones, Amy L. Russell, Veronica A. Brown

Amy L. Russell

Brazilian free-tailed bats (Tadarida brasiliensis) are one of the most widely distributed bat species in the Americas, often engaging in rapid, long-distance dispersals, Here, we document that, since ca. 2007, these bats have expanded their range into western North Carolina, eastern Tennessee, and Virginia. Reports from wildlife control professionals, wildlife rehabilitators, regional submissions of bats for rabies testing, acoustic monitoring, and the presence of T. brasiliensis in buildings and bat houses indicate that these bats are now established in year-round colonies in areas previously thought outside their range limits. The geographic distributions of many organisms are currently shifting …


Population Structure, Connectivity, And Phylogeography Of Two Balistidae With High Potential For Larval Dispersal: Balistes Capriscus And Balistes Vetula, Luca Antoni May 2017

Population Structure, Connectivity, And Phylogeography Of Two Balistidae With High Potential For Larval Dispersal: Balistes Capriscus And Balistes Vetula, Luca Antoni

Dissertations

The gray triggerfish (Balistes capriscus) and the queen triggerfish (Balistes vetula) are two exploited reef fish distributed in tropical and temperate shelf waters of the Atlantic Ocean and the Mediterranean Sea. Both species are highly sedentary as adults but disperse pelagic larvae for extended periods of time potentially allowing connectivity across long distances under the action of oceanic currents. In this work population structure, phylogeography, and migration patterns were examined in the two species and contrasted with predictions of larval transport based on surface circulation data. A total of 1,017 gray triggerfish from twelve sampling localities …


Hitching A Ride: First Record Of A Least Chipmunk (Tamias Minimus) In Eastern Nebraska, Keith Geluso, Michael L. Forsberg Mar 2017

Hitching A Ride: First Record Of A Least Chipmunk (Tamias Minimus) In Eastern Nebraska, Keith Geluso, Michael L. Forsberg

Transactions of the Nebraska Academy of Sciences and Affiliated Societies

On 10 October 2016, a Least Chipmunk (Tamias minimus) was discovered in a residential area of Lincoln, Lancaster County, Nebraska. The closest populations of Least Chipmunks reside > 640 km to the west in northwestern Nebraska and southeastern Wyoming. The most parsimonious explanation for this unusual observation is that the chipmunk was transported to the city by humans. A likely scenario is that the chipmunk hitched a ride to Lincoln in a motor vehicle on 2 October 2016, when one of us drove 1500 km in a single day from Jackson, Teton County, Wyoming, after residing in that area …


Ecological And Evolutionary Interactions Between Song Sparrows (Melospiza Melodia) And Their Bloodborne Parasites, Yanina Sarquis-Adamson Feb 2015

Ecological And Evolutionary Interactions Between Song Sparrows (Melospiza Melodia) And Their Bloodborne Parasites, Yanina Sarquis-Adamson

Electronic Thesis and Dissertation Repository

Local adaptation is the result of natural selection operating at a local scale, such that trade-offs in fitness across different environments result in individuals having higher fitness in their place of origin than when transported into a foreign environment. Populations may become locally adapted to features of their abiotic environment, or in the case of coevolutionary arms races between hosts and parasites, to other species comprising their biotic environment. If host populations are adapted to their local (sympatric) parasites, or conversely if parasites are adapted to their local hosts, then interactions with local parasite strains may influence the fitness consequences …


Documentation Of The Black-Footed Ferret, Mustela Nigripes On The Standing Rock Indian Reservation, Mobridge, South Dakota, Michael P. Gutzmer, Jeffrey C. Kelly Oct 2014

Documentation Of The Black-Footed Ferret, Mustela Nigripes On The Standing Rock Indian Reservation, Mobridge, South Dakota, Michael P. Gutzmer, Jeffrey C. Kelly

Transactions of the Nebraska Academy of Sciences and Affiliated Societies

Since 1991, 19 specific black-footed ferret reintroduction projects have been conducted across 8 States, Canada, and Mexico. All five of the first ferret reintroductions (from 1991 to 1996) continue to be occupied by ferrets. The photographs of October 31 and November 1 are the first unequivocal documentation of black-footed ferrets on the Standing Rock Indian Reservation. Ferrets observed on Standing Rock may be dispersals from the nearby Cheyenne River Sioux Indian Reservation to the south. The nearest re-introduction site for ferrets is approximately 20 miles away, in Whitehorse, South Dakota, and the observation of ferrets on Standing Rock could document …


Combining Demographic And Genetic Factors To Assess Population Vulnerability In Stream Species, Erin Landguth, C. C. Muhlfeld, R. S. Waples, L. Jones, Winsor H. Lowe, Diane C. Whited, J. Lucotch, H. Neville, Gordon Luikart Sep 2014

Combining Demographic And Genetic Factors To Assess Population Vulnerability In Stream Species, Erin Landguth, C. C. Muhlfeld, R. S. Waples, L. Jones, Winsor H. Lowe, Diane C. Whited, J. Lucotch, H. Neville, Gordon Luikart

Biological Sciences Faculty Publications

Accelerating climate change and other cumulative stressors create an urgent need to understand the influence of environmental variation and landscape features on the connectivity and vulnerability of freshwater species. Here, we introduce a novel modeling framework for aquatic systems that integrates spatially explicit, individual-based, demographic and genetic (demogenetic) assessments with environmental variables. To show its potential utility, we simulated a hypothetical network of 19 migratory riverine populations (e.g., salmonids) using a riverscape connectivity and demogenetic model (CDFISH). We assessed how stream resistance to movement (a function of water temperature, fluvial distance, and physical barriers) might influence demogenetic connectivity, and hence, …


Population Genetic Structure In The Pitcher Plant Flesh Fly Fletcherimyia Fletcheri, John R. O'Leary Apr 2014

Population Genetic Structure In The Pitcher Plant Flesh Fly Fletcherimyia Fletcheri, John R. O'Leary

Electronic Thesis and Dissertation Repository

The study of population genetic structure in the pitcher plant flesh fly, Fletcherimyia fletcheri, is an important step in bettering our understanding of dispersal abilities, gene flow, and behavior in the species. In this paper, an extended sampling of populations across Algonquin Provincial Park was performed to elucidate an effective scale of genetic differentiation in F. fletcheri. Genetic differentiation between sites was compared to interceding landscape composition, and digital dispersal models were developed, testing the hypothesis that F. fletcheri uses aquatic tributaries for dispersal between peatlands. Data were collected on 613 specimens from 15 populations, and population differentiation …


Genetic Structure Of Little Brown Bats (Myotis Lucifugus) Corresponds With Spread Of White-Nose Syndrome Among Hibernacula, Cassandra M. Miller-Butterworth, Maarten J. Vonhof, Joel Rosenstern, Greg G. Turner, Amy L. Russell Feb 2014

Genetic Structure Of Little Brown Bats (Myotis Lucifugus) Corresponds With Spread Of White-Nose Syndrome Among Hibernacula, Cassandra M. Miller-Butterworth, Maarten J. Vonhof, Joel Rosenstern, Greg G. Turner, Amy L. Russell

Amy L. Russell

Until recently, the little brown bat (Myotis lucifugus) was one of the most common bat species in North America. However, this species currently faces a significant threat from the emerging fungal disease white-nose syndrome (WNS). The aims of this study were to examine the population genetic structure of M. lucifugus hibernating colonies in Pennsylvania (PA) and West Virginia (WV), and to determine whether that population structure may have influenced the pattern of spread of WNS. Samples were obtained from 198 individuals from both uninfected and recently infected colonies located at the crest of the disease front. Both mitochondrial (636 bp …


Variation In The Local Population Dynamics Of The Short-Lived Opuntia Macrorhiza (Cactaceae), Chirakkal V. Haridas, Kathleen Keeler, Brigitte Tenhumberg Jan 2014

Variation In The Local Population Dynamics Of The Short-Lived Opuntia Macrorhiza (Cactaceae), Chirakkal V. Haridas, Kathleen Keeler, Brigitte Tenhumberg

School of Biological Sciences: Faculty Publications

Spatio-temporal variation in demographic rates can have profound effects for population persistence, especially for dispersal-limited species living in fragmented landscapes. Long-term studies of plants in such habitats help with understanding the impacts of fragmentation on population persistence but such studies are rare. In this work we reanalyzed demographic data from seven years of the short-lived cactus Opuntia macrorhiza var. macrorhiza at five plots in Boulder, Colorado. Previous work combining data from all years and all plots predicted a stable population (deterministic log λ ≈ 0). This approach assumed that all five plots were part of a single population. Since the …


The Cumulative Effects Of Management On The Population Dynamics Of The Double-Crested Cormorant Phalacrocorax Auritus In The Great Lakes, Alban Guillaumet, Brian S. Dorr, Guiming Wang, Terry J. Doyle Jan 2014

The Cumulative Effects Of Management On The Population Dynamics Of The Double-Crested Cormorant Phalacrocorax Auritus In The Great Lakes, Alban Guillaumet, Brian S. Dorr, Guiming Wang, Terry J. Doyle

Brian S Dorr

Wildlife species have been subject to control efforts throughout human history due to real or alleged human–wildlife conflicts. The Double-crested Cormorant Phalacrocorax auritus in the interior of North America is no exception, with recent population growth leading to increased conflicts and consequently the development of many control programmes. These control programmes are usually conducted at local scales, often with little or no effort to assess their cumulative effects at the population level. We attempted the first comprehensive assessment of the cumulative effects of control at various spatio-temporal scales, focusing on 199 colonies of Double-crested Cormorant monitored during a 29-year period. …


Dispersal Of Stable Flies (Diptera: Muscidae) From Larval Developmental Sites., David B. Taylor, Roger D. Moon, Jack B. Campbell, Dennis R. Berkebile, Philip J. Scholl, Alberto B. Broce, Jerome A. Hogsette Jan 2010

Dispersal Of Stable Flies (Diptera: Muscidae) From Larval Developmental Sites., David B. Taylor, Roger D. Moon, Jack B. Campbell, Dennis R. Berkebile, Philip J. Scholl, Alberto B. Broce, Jerome A. Hogsette

David B Taylor

Seven mark-recapture studies were conducted over 3 yr to assess dispersal of newly emerging adult stable flies, Stomoxys calcitrans L., from larval development sites in a mixed agricultural environment in northeastern Nebraska. Infested hay debris piles were marked by dusting their surfaces with fluorescent pigments, adults were captured with surrounding grids of Alsynite sticky traps, and specimens were dissected to determine feeding histories and reproductive age. Distances and directions of 3,889 marked specimens indicated males and females dispersed equally and in all directions. Midguts of males and females were equally likely to contain blood-meal remnants. Percentage with blood remnants and …


Genetic Structure Of East Antarctic Populations Of The Moss Ceratodon Purpureus, L. J. Clarke, D. J. Ayre, Sharon A. Robinson Nov 2009

Genetic Structure Of East Antarctic Populations Of The Moss Ceratodon Purpureus, L. J. Clarke, D. J. Ayre, Sharon A. Robinson

Sharon Robinson

The capacity of the polar flora to adapt is of increasing concern given current and predicted environmental change in these regions. Previous genetic studies of Antarctic mosses have been of limited value due to a lack of variation in the markers or non-specificity of the methods used. We examined the power of five microsatellite loci developed for the cosmopolitan moss Ceratodon purpureus to detect genetically distinct clones and infer the distribution of clones within and among populations from the Windmill Islands, East Antarctica. Our microsatellite data suggest extraordinarily high levels of variation reported in RAPD studies were artificially elevated by …


Familiarity With Breeding Habitat Improves Daily Survival In Colonial Cliff Swallows, Charles R. Brown, Mary Bomberger Brown, Kathleen R. Brazeal Oct 2008

Familiarity With Breeding Habitat Improves Daily Survival In Colonial Cliff Swallows, Charles R. Brown, Mary Bomberger Brown, Kathleen R. Brazeal

School of Natural Resources: Faculty Publications

One probable cost of dispersing to a new breeding habitat is unfamiliarity with local conditions such as the whereabouts of food or the habits of local predators, and consequently immigrants may have lower probabilities of survival than more experienced residents. Within a breeding season, estimated daily survival probabilities of cliff swallows, Petrochelidon pyrrhonota, at colonies in southwestern Nebraska, USA, were highest for birds that had always nested at the same site, followed by those for birds that had nested there in some (but not all) past years. Daily survival probabilities were lowest for birds that were naive immigrants to …


Philopatry And Dispersal In Whooping Cranes, Brian W. Johns, J. Paul Goossen, Ernie Kuyt, Lea Craig-Moore Jan 2005

Philopatry And Dispersal In Whooping Cranes, Brian W. Johns, J. Paul Goossen, Ernie Kuyt, Lea Craig-Moore

Proceedings of the North American Crane Workshop

The natal and breeding dispersal of endangered whooping cranes (Grus americana) was investigated using information collected between 1978-2002 on the nesting grounds in and near Wood Buffalo National Park, Alberta-Northwest Territories. A minimum of 77% of the juveniles color-banded near their natal sites returned to the breeding grounds. Sex-biased natal dispersal was not observed. At least 76% of first-time breeders nested within 20 km of their natal site. Pioneering was rare and most cranes nested on the primary nesting areas adjacent to the Sass and Klewi rivers. The mechanism enhancing natal philopatry is probably related to learning the …


Linking Dispersal To Local Population Dynamics: A Case Study Using A Headwater Salamander System, Winsor H. Lowe Jan 2003

Linking Dispersal To Local Population Dynamics: A Case Study Using A Headwater Salamander System, Winsor H. Lowe

Dartmouth Scholarship

Dispersal can strongly influence local population dynamics and may be critical to species persistence in fragmented landscapes. Theory predicts that dispersal by resident stream organisms is necessary to offset the loss of individuals to downstream drift. However, there is a lack of empirical data linking dispersal and drift to local population dynamics in streams, leading to uncertainty regarding the general demographic significance of these processes and the power of drift to explain observed dispersal patterns. I assessed the contribution of dispersal along a first-order stream to population dynamics of the headwater salamander Gyrinophilus porphyriticus (Plethodontidae). I conducted mark–recapture surveys of …