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High Dispersal Ability Is Related To Fast Life-History Strategies, Noelle G. Beckman, James M. Bullock, Roberto Salguero-Gomez

Ecology Center Publications

1. Seed dispersal is an essential, yet often overlooked process in plant ecology and evolution, affecting adaptation capacity, population persistence and invasiveness. A species’ ability to disperse is expected to covary with other life-history traits to form dispersal syndromes. Dispersal might be linked to the rate of life history, fecundity or generation time, depending on the relative selection pressures of bethedging, kin competition or maintaining gene flow. However, the linkage between dispersal and plant life-history strategies remains unknown because it is difficult to observe, quantify and manipulate the influence of dispersal over large spatiotemporal scales.

2. We integrate datasets describing …

Variable Utilization Of Shelf Break-Associated Habitats By Chick-Brooding Rhinoceros Auklets In The California Current System, Bradley Wilkinson, Jaime Jahncke, Pete Warzybok, Russell Bradley, Scott A. Shaffer

Faculty Publications, Biological Sciences

Identifying frequently complex and dynamic spatial distributions of marine predators via the modeling of at-sea observations can be inherently challenging, especially when attempting to predict habitats of specific populations. Remotely-sensed tracking devices provide a viable alternative way to gather this information. We collected fine-scale spatiotemporal movement data for a small seabird, the rhinoceros auklet Cerorhinca monocerata, in the California Current System. Chick-brooding adults nesting on Southeast Farallon Island were outfitted with GPS loggers during the 2015 and 2016 breeding seasons (n = 15). Along with basic movement parameters, kernel density and residence time analyses were conducted to characterize at-sea distribution …

Demographic Hallmarks Of An Overbrowsed Population State In American Ginseng, James B. Mcgraw, Jennifer L. Chandler

Faculty & Staff Scholarship

Effects of high deer herbivory in North America on populations of favored plant browse species have been well-documented, however since less palatable plants now dominate the understory, we asked whether these species could be vulnerable as well, and if so, what symptoms might signal that this was occurring? Using American ginseng (Panax quinque- foliusL.) as our representative less palatable understory plant, we compared two sub- populations within a single natural population that were differentially exposed to browse; one isolated from deer by growing atop a large, flat-topped boulder, and a browse-exposed subpopulation in the surrounding low-lying area. We tested the …

Demography And Dendrochronology Of A Disjunct Population Of Eastern Hemlock In Southwestern Ohio, Marie Johnson

Browse all Theses and Dissertations

Edge and isolated plant populations provide information about the resilience and the most basic resource needs of a species. Plant demography examines changes in population size and structure over time. An isolated, disjunct eastern hemlock population in Clifton Gorge State Nature Preserve, Yellow Springs, Ohio consists of two distinct subpopulations each with different environmental characteristics, reproductive capacities, and health ratings. Both subpopulations at Clifton Gorge were found to exhibit significant decreases in average annual ring width through time. Linear regression modeling determined that average annual growing season precipitation and temperature were the strongest predictors of these growth trends. A comparative …

Time-Lagged Effects Of Weather On Plant Demography: Drought And Astragalus Scaphoides, Brigitte Tenhumberg, Elizabeth E. Crone, Satu Ramula, Andrew J. Tyre

School of Biological Sciences: Faculty Publications

Temperature and precipitation determine the conditions where plant species can occur. Despite their significance, to date, surprisingly few demographic field studies have considered the effects of abiotic drivers. This is problematic because anticipating the effect of global climate change on plant population viability requires understanding how weather variables affect population dynamics. One possible reason for omitting the effect of weather variables in demographic studies is the difficulty in detecting tight associations between vital rates and environmental drivers. In this paper, we applied Functional Linear Models (FLMs) to long-term demographic data of the perennial wildflower, Astragalus scaphoides, and explored sensitivity of …

Commentary: Research Recommendations For Understanding The Decline Of American Kestrels (Falco Sparverius) Across Much Of North America, Christopher J.W. Mcclure, Sarah E. Schulwitz, Richard Van Buskirk, Benjamin P. Pauli, Julie A. Heath

Biology Faculty Publications and Presentations

Across much of North America, populations of American Kestrels (Falco sparverius) have been in decline for decades (Farmer et al. 2008, Farmer and Smith 2009, Smallwood et al. 2009a, Paprocki et al. 2014, Sauer et al. 2014). Hypothesized causes of kestrel declines include predation by Cooper's Hawks (Accipiter cooperii; Farmer et al. 2008), pathogens (e.g., Nemeth et al. 2006), habitat loss (Sullivan and Wood 2005, Farmer et al. 2008, Bolgiano et al. 2015), pesticides (Smallwood et al. 2009a, Rattner et al. 2015), and climate change (Steenhof and Peterson 2009b), yet no hypothesized factor has been supported …

Landscape Genetics Of The California Tiger Salamander: Inferences From Multiple Methods, Samantha Gabrielle Thomas

Masters Theses & Specialist Projects

Landscape genetics is a rapidly growing field of study that compares patterns of gene flow among populations with habitat heterogeneity across a landscape to infer the interaction between dispersal of individuals and their physical environment. Empirical data generated from a landscape genetics study can inform conservation and management strategies, making the field increasing popular. However, concerns have arisen in the literature that the field is expanding faster than the analytic framework that supports it. Multiple methods for generating estimates of the association among habitat types and dispersal (i.e., least-cost paths and resistance surfaces) have been proposed, and there is a …

Plant-Microbial Interactions Are Strong Determinants Of Plant Population And Community Dynamics, Yan-Yi Anny Chung 9485698

Biology ETDs

Plant-microbial interactions are ubiquitous and yet the consequences of these interactions on plant population and community dynamics are relatively unknown. Here, we used two different classes of plant-microbial interactions to examine their effects on key plant population and community characteristics such as commonness and rarity, competition and coexistence, as well as community stability.

Vertically-transmitted endophytes had stage-dependent effects on the population growth of two grass species Poa sylvestris and Poa alsodes, and generally increased host population growth rates. However, it was the intrinsic demographic advantage of P. sylvestris that allowed its population to grow at a much faster rate …

Rapid Increase In Genetic Diversity In An Endemic Patagonian Tuco-Tuco Following A Recent Volcanic Eruption, Jeremy L. Hsu, Sharon Kam, Mauro N. Tammone, Eileen A. Lacey, Elizabeth A. Hadly

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Catastrophic natural events can have profound impacts on patterns of genetic diversity. Due to the typically unpredictable nature of such phenomena, however, few studies have been able to directly compare patterns of diversity before and after natural catastrophic events. Here, we examine the impacts of a recent volcanic eruption in southern Chile on genetic variation in the colonial tuco-tuco (Ctenomys sociabilis), a subterranean species of rodent endemic to the area most affected by the June 2011 eruption of the Puyehue-Cordón Caulle volcanic complex. To provide a comparative context for interpreting changes in genetic variation in this species, we …

Field Estimates Of Parentage Reveal Sexually Antagonistic Selection On Body Size In A Population Of Anolis Lizards, Mary C. Duryea, Patrick Bergeron, Zachary Clare-Salzler, Ryan Calsbeek

Dartmouth Scholarship

Sexual dimorphism evolves when selection favors different phenotypic optima between the sexes. Such sexually antagonistic selection creates intralocus sexual conflict when traits are genetically correlated between the sexes and have sex‐specific optima. Brown anoles are highly sexually dimorphic: Males are on average 30% longer than females and 150% heavier in our study population. Viability selection on body size is known to be sexually antagonistic, and directional selection favors large male size whereas stabilizing selection constrains females to remain small. We build on previous studies of viability selection by measuring sexually antagonistic selection using reproductive components of fitness over three generations …

Macgillivray's Seaside Sparrow (Ammodramus Maritimus Macgillivraii) Breeding Biology & Population Density At Tom Yawkey Wildlife Center, Yianni P. Laskaris

Electronic Theses and Dissertations

MacGillivray's Seaside Sparrow (Ammodramus maritimus macgillivraii) is a coastal marsh species sensitive to habitat alteration and threatened by coastal wetland loss. Data on seaside sparrow distribution, breeding success, and critical habitats are lacking in South Carolina. To better understand the demographics and incubation behavior of the species, I monitored breeding success, densities, song output, and presence of predators at three 7-hectare plots at the densest known population in the state. I also placed temperature data-loggers in a subset of nests to discern any links between incubation behavior and nest fate. Densities varied from a low of 5 birds/ha in a …

Repeated Trait Evolution Driven By Divergent Natural Selection At Early And Late Stages Of Speciation, Spencer J. Ingley

Theses and Dissertations

Speciation – the process by which new species arise – is of fundamental importance in the biological sciences. The means by which new species arise, and the relationship among living species, has been a topic that has captivated both lay and scientific observers for centuries. In recent years, the study of speciation has enjoyed increased attention, resulting in significant advances in our understanding of how species form. Although our understanding of the processes that contribute to speciation has increased dramatically in recent years, our knowledge of how reproductive barriers accumulate as speciation proceeds is still limited. Thus, studies that evaluate …

Demographic Survey Of The Sohisika (Schizolaena Tampoketsana), James Lucas

CLAS: Colby Liberal Arts Symposium

The sohisika (Schizolaena tampoketsana; family Sarcolaenaceae) is a little-known, highly threatened angiosperm endemic to the forest fragments and savanna of the Hauts Plateaux region at Ankafobe Commune, Madagascar. Through targeted surveillance of sohisika at Ankafobe, this study aimed primarily to characterize the demography of the sohisika via GPS mapping of latitude, longitude, and altitude, through dendrometric measures such as height and diameter at breast height (DBH), and through calculation of distribution patterns via Morisitas index. Secondary goals aimed to describe the ecology of the sohisika within its environment and hoped to identify patterns between age class, aspect, habitat, and surrounding …

Early Successional Microhabitats Allow The Persistence Of Endangered Plants In Coastal Sand Dunes, Eleanor A. Pardini, Kyle E. Vickstrom, Tiffany M. Knight

Biology Faculty Research

Many species are adapted to disturbance and occur within dynamic, mosaic landscapes that contain early and late successional microhabitats. Human modification of disturbance regimes alters the availability of microhabitats and may affect the viability of species in these ecosystems. Because restoring historical disturbance regimes is typically expensive and requires action at large spatial scales, such restoration projects must be justified by linking the persistence of species with successional microhabitats. Coastal sand dune ecosystems worldwide are characterized by their endemic biodiversity and frequent disturbance. Dune-stabilizing invasive plants alter successional dynamics and may threaten species in these ecosystems. We examined the distribution …

The Reproductive Biology Of The Finetooth Shark, Carcharhinus Isodon, In The Northwest Atlantic Ocean, Amanda N. Brown

UNF Graduate Theses and Dissertations

Shark fisheries are a multimillion dollar industry in the United States and have significant contributions both recreationally and commercially. In order to maintain this industry, fisheries must be properly managed. An understanding of life history and reproduction is crucial in order to adequately manage shark fisheries. The finetooth shark, Carcharhinus isodon, is a member of the small coastal shark (SCS) fishery complex. It is found in Atlantic waters from South Carolina to Florida and throughout the Gulf of Mexico. This species has recently come under increased fishing pressure and has previously been overfished. New data is needed in order …

Impacts Of Environmental Pressures On The Reproductive Physiology Of Subpopulations Of Black Rhinoceros (Diceros Bicornis Bicornis) In Addo Elephant National Park, South Africa, Elizabeth Freeman, Jordana Meyer, Jed Bird, John Adendorff, Bruce A. Schulte, Rachel Santymire

Biology Faculty Publications

Black rhinoceros are an icon for international conservation, yet little is known about their physiology due to their secretive nature. To overcome these challenges, non-invasive methods were used to monitor rhinoceros in two sections of Addo Elephant National Park, South Africa, namely Addo and Nyathi. These sections were separated by a public road, and the numbers of elephants, predators and tourists were higher in Addo. Faecal samples (n = 231) were collected (from July 2007 to November 2010) from known individuals and analysed for progestagen and androgen metabolite (FPM and FAM, respectively) concentrations. As biotic factors could impact reproduction, …

Integrated Assessment Of Biological Invasions, Inés Ibáñez, Jeffrey M. Diez, Luke P. Miller, Julian D. Olden, Cascade J.B. Sorte, Dana M. Blumenthal, Bethany A. Bradley, Carla M. D'Antonio, Jeffrey S. Dukes, Regan I. Early, Edwin D. Grosholz, Joshua J. Lawler

Faculty Publications, Biological Sciences

As the main witnesses of the ecological and economic impacts of invasions on ecosystems around the world, ecologists seek to provide the relevant science that informs managers about the potential for invasion of specific organisms in their region(s) of interest. Yet, the assorted literature that could inform such forecasts is rarely integrated to do so, and further, the diverse nature of the data available complicates synthesis and quantitative prediction. Here we present a set of analytical tools for synthesizing different levels of distributional and/or demographic data to produce meaningful assessments of invasion potential that can guide management at multiple phases …

Reproductive Biology Of The Bonnethead (Sphyrna Tiburo) From The Southeastern U.S. Atlantic Coast, Melissa I. Gonzalez De Acevedo

UNF Graduate Theses and Dissertations

Understanding the life history of marine wildlife is essential for the management of both commercial and recreational fisheries. Bonnetheads (Sphyrna tiburo) are a component of the small coastal shark (SCS) fishery complex, and are caught regularly in both types of fisheries. Despite being well studied in the Gulf of Mexico, little is known about bonnetheads from the U.S. Atlantic coast. The goal of the first component of this study was to provide new, key information on their life history to improve management of U.S. Atlantic populations, particularly by identifying reproductive seasonality, periodicity and fecundity. This was accomplished by examining sexually …

The Correlation Between Veldt Grass (Ehrharta Calycina) And Reproductive Condition Of The Lompoc Kangaroo Rat (Dipodomys Heermanni Arenae), Jacqueline Mae Bates

Biological Sciences

The invasive species, Veldt grass (Ehrharta calycina), has come to dominate coastal dune shrub vegetation along the Central Coast of California. Along with creating many land management obstacles, this grass has become dominant in the open habitat of Lompoc Kangaroo Rats (Dipodomys heermanni arenae). It is hypothesized that, due to a lack of suitable kangaroo rat habitat, during the breeding season months of March and April, there will be significantly fewer reproductively active females in areas of relatively high Veldt grass cover as opposed to relatively low Veldt grass cover. This study used data from a …

Examining Mitochondrial Genetic Diversity In A Population Of Eastern Hognose Snakes (Heterodon Platirhinos) In Cape Cod, Ma, Stephanie R. Parelli

Theses, Dissertations and Culminating Projects

The Eastern Hognose snake (Heterodon platirhinos) is a relatively poorly studied species found in the eastern half of the United States from southern New England and Ontario south along the Atlantic coast to Florida and west to Texas, Kansas, Nebraska, and South Dakota. In the Northeastern part of their range they are considered to be a species of regional conservation concern by the Northeast Endangered Species and Wildlife Diversity Technical Committee. They are protected by conservation measures in the states of Rhode Island, Connecticut, and Massachusetts, and are listed as endangered by the state of New Hampshire. The purpose of …

Increasing Liana Abundance And Basal Area In A Tropical Forest: The Contribution Of Long‐Distance Clonal Colonization, Suzanne R. Yorke, Stefan A. Schnitzer, Joseph Mascaro, Susan G. Letcher, Walter P. Carson

Biological Sciences Faculty Research and Publications

Recent evidence suggests that liana abundance and biomass are increasing in Neotropical forests, representing a major structural change to tropical ecosystems. Explanations for these increases, however, remain largely untested. Over an 8‐yr period (1999–2007), we censused lianas in nine, 24 × 36 m permanent plots in old‐growth and selectively logged forest at La Selva Biological Station, Costa Rica to test whether: (1) liana abundance and basal area are increasing in this forest; (2) the increase is being driven by increased recruitment, decreased mortality, or both; and (3) long‐distance clonal colonization explains the increase in liana abundance and basal area. We …

Prolonged Dormancy Interacts With Senescence For Two Perennial Herbs, Juha Tuomi, Elizabeth E. Crone, Jennifer R. Gremer, Anne Jakalaniemi, Peter Lesica, Bard Pedersen, Satu Ramula

Biological Sciences Faculty Publications

1. Senescence is characterized by a decline in survival, fecundity and reproductive value with age among adult individuals. Simple age-dependent life cycles progress forward through developmental stages, with each successive stage being characterized by age-specific vital rates. In contrast, size- or stage-based life cycles for perennial plants are more complex and often include stasis and retrogression to previous vegetative or reproductive life stages, indicating possible slowing or even reversing the developmental progress.

2. Many plants remain in nonemergent, below-ground stages during the growing season (prolonged dormancy), which may affect the process of senescence. Stasis in the dormant stage implies that …

Greater Sexual Reproduction Contributes To Differences In Demography Of Invasive Plants And Their Noninvasive Relatives, Jean H. Burns, Eleanor A. Pardini, Michele R. Schutzenhofer, Y Anny Chung, Katie J. Seidler, Tiffany M. Knight

Biology Faculty Research

An understanding of the demographic processes contributing to invasions would improve our mechanistic understanding of the invasion process and improve the efficiency of prevention and control efforts. However, field comparisons of the demography of invasive and noninvasive species have not previously been conducted. We compared the in situ demography of 17 introduced plant species in St. Louis, Missouri, USA, to contrast the demographic patterns of invasive species with their less invasive relatives across a broad sample of angiosperms. Using herbarium records to estimate spread rates, we found higher maximum spread rates in the landscape for species classified a priori as …

Juvenile Ornamentation: Its Evolution, Genetic Basis, And Variation Across Habitats, Angela Tringali

Electronic Theses and Dissertations

Ornamental traits are considered honest advertisements of fitness, and their evolution is usually explained in terms of sexual selection. This explanation remains unsatisfactory in some instances, for example, juvenile birds whose plumage is molted prior to adulthood and breeding. I first evaluate whether juvenile plumage reflectance signals dominance status in the Federally Threatened Florida scrub-jay (Aphelocoma coerulescens) using a combination of observational and experimental methods. Then I estimate the heritability, non-genetic maternal and environmental effects, and strength of selection on juvenile plumage reflectance using archived feather samples and a pedigree constructed from historical nest records. Finally, I compare plumage reflectance …

Demography And Reproductive Biology Of The Gopher Tortoise (Gopherus Polyphemus) Population At White Oak Plantation, Nassau County, Florida, Julia Rachel Smith

UNF Graduate Theses and Dissertations

The demography and reproductive biology of the gopher tortoise (Gopherus polyphemus) was studied for two years at White Oak Plantation (WOP), located in northeast Florida along the St. Mary’s river. Two sub‐populations were studied in regions I referred to as Site A and Site B. I located 312 burrows and captured 109 different tortoises, either by hand or using bucket traps. Tortoise density was 4.48/ha at Site A and only 1.15/ha at Site B. Juveniles were the most abundant age class overall, while hatchlings were numerous at Site A but virtually absent at Site B. The combined sex ratio for …

Survival, Breeding Frequency, And Migratory Orientation In The Jefferson Salamander, Ambystoma Jeffersonianum, Stephen P. De Lisle, Kristine L. Grayson

Biology Faculty Publications

Accurate estimates of demographic parameters, such as survival and breeding frequency, are necessary for the conservation and management of animal populations. Additionally, life-history data are required for gaining an empirical understanding of the ecology of natural populations. We monitored a population of Jefferson Salamanders (Ambystoma jeffersonianum) breeding in a permanent mountain-top pond at the southern limit of this species’ geographic range in Virginia over four years. We used closed multistate mark-recapture models with Pollock's robust design to estimate the demographic parameters of this population. Additionally, we used point-of-capture data to compare the orientation of migrations into and out …

Molecular Evolution And Historical Biogeography Of New World Birds, Brian T. Smith

UNLV Theses, Dissertations, Professional Papers, and Capstones

Deciphering the patterns of how biodiversity has evolved across time and space has remained a fundamental objective for biologists for the last 200 years. Researchers are faced with the challenge of interpreting the complexity of evolutionary patterns that have been generated over the deep history of the Earth. The advancement of DNA sequencing technology has yielded a new and powerful genetic toolkit that has allowed biologists to address novel evolutionary questions. For my dissertation research, I used molecular genetics and a statistical framework to study the evolution and historical biogeography of birds distributed in North and South America. My dissertation …

Species Trees And Species Delimitation With Multilocus Data And Coalescent-Based Methods: Resolving The Speciation History Of The Liolaemus Darwinii Group (Squamata, Tropiduridae), Arley Camargo Bentaberry

Theses and Dissertations

The inference of species boundaries and phylogenetic relationships are fundamental for evolutionary, ecological, and conservation studies. The resolution of species boundaries and the inference of phylogenetic relationships among species are required to define the units of analysis and to find the most closely related units for evaluating alternative models of speciation. I highlight lizards as model organisms for ecological and evolutionary studies, emphasizing their contributions to advances in understanding linkages between phylogeography and speciation. In this dissertation, I focus on the phylogenetic relationships of the lizards in the Liolaemus darwinii group, and the species boundaries of a nested clade within …

Will The Use Of Less Fecund Cultivars Reduce The Invasiveness Of Perennial Plants?, Tiffany M. Knight, Kayri Havens, Pati Vitt

Biology Faculty Research

Many invasive species were originally introduced for horticultural purposes, and several continue to be profitable for the green (nursery, horticulture, and landscape) industry. Recently, some plant suppliers have marketed less fecund cultivars of several invasive species, including glossy buckthorn (Frangula alnus), burning bush (Euonymus alatus), and Japanese barberry (Berberis thunbergii), as “safe” alternatives to invasive relatives. We use published matrix population models to simulate the effect of reducing fecundity on the population growth rates of invasive species. We show that large changes in fecundity result in relatively small changes to the population growth rates of long-lived species, which suggests that …

The Effects Of Urbanization On Cypress (Taxodium Distichum) In Central Florida, Lisa A. Mccauley

Electronic Theses and Dissertations

Urbanization is accelerating in the United States and is contributing to fragmentation of natural habitats, causing changes in species composition and declines in native species. Human population growth in Orlando is typical of growth in the southeastern United States and throughout the range of cypress (Taxodium distichum). Orlando has numerous isolated cypress wetlands, called cypress domes, and many remain among the current urbanized area. This makes Orlando ideal to study the effects of urbanization on cypress domes. Specifically, I tested how urbanization and its effects on fragmentation, hydrology, and fire regime) affected (a) the numbers and spatial pattern of cypress …