Search USGS⌕ Search

SEARCH · Search USGS

Results for “Evolutionary Biology”

Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 37 records · Page 2Linked to original sources
USGS2013

The airspace is habitat

A preconception concerning habitat persists and has gone unrecognized since use of the term first entered the lexicon of ecological and evolutionary biology many decades ago. Specifically, land and water are considered habitats, while the airspace is not. This might at first seem a reasonable, if unintended, demarcation, since years of education and personal experience as well as limits to perception predispose a traditional view of habitat. Nevertheless, the airspace satisfies the definition and functional role of a habitat, and its recognition as habitat may have implications for policy where expanding anthropogenic development of airspace could impact the conservation of species and subject parts of the airspace to formalized legal protection.

Trends in Ecology and Evolution↗
USGS2016

Testing for variation in taxonomic extinction probabilities: A suggested methodology and some results

Several important questions in evolutionary biology and paleobiology involve sources of variation in extinction rates. In all cases of which we are aware, extinction rates have been estimated from data in which the probability that an observation (e.g., a fossil taxon) will occur is related both to extinction rates and to what we term encounter probabilities. Any statistical method for analyzing fossil data should at a minimum permit separate inferences on these two components. We develop a method for estimating taxonomic extinction rates from stratigraphic range data and for testing hypotheses about variability in these rates. We use this method to estimate extinction rates and to test the hypothesis of constant extinction rates for several sets of stratigraphic range data. The results of our tests support the hypothesis that extinction rates varied over the geologic time periods examined. We also present a test that can be used to identify periods of high or low extinction probabilities and provide an example using Phanerozoic invertebrate data. Extinction rates should be analyzed using stochastic models, in which it is recognized that stratigraphic samples are random variates and that sampling is imperfect.

Paleobiology↗
USGS2022

Spatial personalities: A meta-analysis of consistent individual differences in spatial behavior

Individual variation in behavior, particularly consistent among-individual differences (i.e., personality), has important ecological and evolutionary implications for population and community dynamics, trait divergence, and patterns of speciation. Nevertheless, individual variation in spatial behaviors, such as home range behavior, movement characteristics, or habitat use has yet to be incorporated into the concepts or methodologies of ecology and evolutionary biology. To evaluate evidence for the existence of consistent among-individual differences in spatial behavior – which we refer to as “spatial personality” – we performed a meta-analysis of 200 repeatability estimates of home range size, movement metrics, and habitat use. We found that the existence of spatial personality is a general phenomenon, with consistently high repeatability (r) across classes of spatial behavior (r = 0.67–0.82), taxa (r = 0.31–0.79), and time between repeated measurements (r = 0.54–0.74). These results suggest: 1) repeatable spatial behavior may either be a cause or consequence of the environment experienced and lead to spatial personalities that may limit the ability of individuals to behaviorally adapt to changing landscapes; 2) interactions between spatial phenotypes and environmental conditions could result in differential reproduction, survival, and dispersal, suggesting that among-individual variation may facilitate population-level adaptation; 3) spatial patterns of species' distributions and spatial population dynamics may be better understood by shifting from a mean field analytical approach towards methods that account for spatial personalities and their associated fitness and ecological dynamics.

Behavioral Ecology↗
USGS2021

Directional selection shifts trait distributions of planted species in dryland restoration

The match between species trait values and local abiotic filters can restrict community membership. An often-implicit assumption of this relationship is that abiotic filters select for a single locally optimal strategy, though difficulty in isolating effects of the abiotic environment from those of dispersal limitation and biotic interactions has resulted in few empirical tests of this assumption. Similar constraints have made it difficult to assess whether the type and intensity of abiotic filters shift along gradients of environmental harshness, as predicted by the stress-dominance hypothesis. We planted 9,216 plants of 29 perennial grass and forb species that had a range of functional trait values and were assigned to a warm, intermediate or cool temperature tolerance pool across eight sites on the Colorado Plateau. We compared the distributions of traits of surviving individuals to null distributions to evaluate whether there were shifts in trait means and variation. Borrowing from phenotypic selection concepts in evolutionary biology, we assessed support for stabilizing, directional and disruptive abiotic filtering of trait distributions and whether these types of filtering varied with initial species pool. Functional composition was significantly different from null distributions for nearly all traits at all sites, with trait variation more restricted in harsher abiotic conditions, supporting the stress-dominance hypothesis. Contrary to expectations, we primarily found evidence for directional selection, which increased in frequency in warm species pools while disruptive selection was found more often in cool and intermediate species pools. Synthesis . This study provides a controlled experimental approach to test the effect of the abiotic environment on plant trait filtering. We found that opportunistic strategies allowing for rapid water acquisition during favourable periods improved survival at warmer sites. Species with these strategies may be expected to benefit from increasing aridity and may be selected for active management efforts. More generally, the prevalence of directional selection may have important implications for dynamic vegetation models that rely on trait distributions for translating environmental variation into ecosystem processes.

Journal of Ecology↗
USGS2011

Predicting phenology by integrating ecology, evolution and climate science

Forecasting how species and ecosystems will respond to climate change has been a major aim of ecology in recent years. Much of this research has focused on phenology – the timing of life‐history events. Phenology has well‐demonstrated links to climate, from genetic to landscape scales; yet our ability to explain and predict variation in phenology across species, habitats and time remains poor. Here, we outline how merging approaches from ecology, climate science and evolutionary biology can advance research on phenological responses to climate variability. Using insight into seasonal and interannual climate variability combined with niche theory and community phylogenetics, we develop a predictive approach for species’ reponses to changing climate. Our approach predicts that species occupying higher latitudes or the early growing season should be most sensitive to climate and have the most phylogenetically conserved phenologies. We further predict that temperate species will respond to climate change by shifting in time, while tropical species will respond by shifting space, or by evolving. Although we focus here on plant phenology, our approach is broadly applicable to ecological research of plant responses to climate variability.

Global Change Biology↗
USGS2020

Latitudinal patterns of alien plant invasions

Latitudinal patterns of biodiversity have long been a central topic in ecology and evolutionary biology. However, while most previous studies have focused on native species, little effort has been devoted to latitudinal patterns of plant invasions (with a few exceptions based on data from sparse locations). Using the most up‐to‐date worldwide native and alien plant distribution data from 801 regions (including islands), we compared invasion levels (i.e. alien richness/total richness) in the Northern and Southern Hemispheres and across continental regions and islands around the globe. Results from quantile regressions using B‐splines to model nonlinearity showed (1) declining richness with increasing latitude, although the highest alien richness occurs at around 40 degrees in both hemispheres, (2) decreasing invasion levels towards higher latitudes on islands but a unimodal pattern in invasion level in continental regions in each hemisphere, (3) significantly higher invasion levels on islands than in continental regions and (4) a greater variability in invasion levels on islands at low latitudes than on high‐latitude islands. In continental regions, only the mid‐latitudes had high variability with both low and high invasion levels. Our findings identified latitudes with invasion hotspots where management is urgently needed, and latitudes with many areas of low invasions but high conservation potential where prevention of future invasions should be the priority.

Journal of Biogeography↗
USGS2019

Parallel signatures of selection at genomic islands of divergence and the major histocompatibility complex in ecotypes of sockeye salmon across Alaska

Understanding the genetic mechanisms that facilitate adaptive radiation is an important component of evolutionary biology. Here, we genotyped 82 neutral SNPs, seven SNPs in islands of divergence identified in a previous study (island SNPs), and a region of the major histocompatibility complex (MHC) in 32 populations of sockeye salmon to investigate whether conserved genes and genomic regions are involved in adaptive radiation. Populations representing three ecotypes were sampled from seven drainages with differing habitats and colonization histories spanning a range of 2,000 km. We found strong signatures of parallel selection across drainages at the island SNPs and MHC, suggesting that the same loci undergo divergent selection during adaptive radiation. However, patterns of differentiation at most island SNPs and the MHC were not associated with ecotypes, suggesting that these loci are responding differently to a mosaic of selective pressures. Our study provides some of the first evidence that conserved genomic islands may be involved in adaptive divergence of salmon populations. Additionally, our data provide further support for the hypothesis that sockeye salmon inhabiting rivers unconnected to lakes harbour similar genetic diversity across large distances, are likely the ancestral form of the species, and have repeatedly recolonized lake systems as they have become available after glacial recession. Finally, our results highlight the value and importance of validating outlier loci by screening additional populations and regions, a practice that will hopefully become more common in the future.

Alaska↗
USGS2013

MODIS phenology image service ArcMap toolbox

Seasonal change is important to consider when managing conservation areas at landscape scales. The study of such patterns throughout the year is referred to as phenology. Recurring life-cycle events that are initiated and driven by environmental factors include animal migration and plant flowering. Phenological events capture public attention, such as fall color change in deciduous forests, the first flowering in spring, and for those with allergies, the start of the pollen season. These events can affect our daily lives, provide clues to help understand and manage ecosystems, and provide evidence of how climate variability can affect the natural cycle of plants and animals. Phenological observations can be gathered at a range of scales, from plots smaller than an acre to landscapes of hundreds to thousands of acres. Linking these observations to diverse disciplines such as evolutionary biology or climate sciences can help further research in species and ecosystem responses to climate change scenarios at appropriate scales. A cooperative study between the National Park Service (NPS), the U.S. Geological Survey (USGS), and the National Aeronautics and Space Administration (NASA) has been exploring how satellite information can be used to summarize phenological patterns observed at the park or landscape scale and how those summaries can be presented to both park managers and visitors. This study specifically addressed seasonal changes in plants, including the onset of growth, photosynthesis in the spring, and the senescence of deciduous vegetation in the fall. The primary objective of the work is to demonstrate that seasonality even in protected areas changes considerably across years. A major challenge is to decouple natural variability from possible trends—directional change that can lead to a permanent and radically different ecosystem state. Trends can be either a gradual degradation of the landscape (often from external influences) or steady improvement (by implementing long-term conservation plans). In either case, it is important to first grasp the magnitude of natural variation so that it is not confused with actual trends. This work used existing and freely available remote sensing data, specifically the NASA-funded 250-meter (m) spatial resolution land-surface phenology product for North America. This product is calculated from an annual record of vegetation health observed by NASA’s Moderate Resolution Imaging Spectroradiometer (MODIS) instrument. The land-surface phenology product is, in essence, a method to summarize all the observations throughout a year into a few key, ecologically relevant “metrics”.

Open-File Report↗
USGS2008

Modeling individual effects in the Cormack-Jolly-Seber Model: A state-space formulation

In population and evolutionary biology, there exists considerable interest in individual heterogeneity in parameters of demographic models for open populations. However, flexible and practical solutions to the development of such models have proven to be elusive. In this article, I provide a state-space formulation of open population capture-recapture models with individual effects. The state-space formulation provides a generic and flexible framework for modeling and inference in models with individual effects, and it yields a practical means of estimation in these complex problems via contemporary methods of Markov chain Monte Carlo. A straightforward implementation can be achieved in the software package WinBUGS. I provide an analysis of a simple model with constant parameter detection and survival probability parameters. A second example is based on data from a 7-year study of European dippers, in which a model with year and individual effects is fitted.

Biometrics↗
USGS2012

Colonizing the world in spite of reduced MHC variation

Reduced immune gene diversity is thought to negatively affect the capacity of organisms to adapt to pathogen challenges, which represent a major force in natural selection. Genes of the Major Histocompatibility Complex (MHC) are the most widely invoked adaptive loci in conservation biology, and have become the most popular genetic markers to investigate pathogen-host interactions in vertebrates. Although MHC genes are the most polymorphic genes described in the vertebrate genome, the extent to which MHC diversity determines the long-term persistence of populations is, unclear and often debated, as recent studies have documented the occurrence of natural populations thriving even after a depletion of MHC diversity caused by genetic drift. Here, we show that some phylogenetically related species belonging to the Falco genus (Aves: Falconidae) present a dramatically low MHC variability that has not precluded, nevertheless, the successful colonization of almost all existing regions and habitats worldwide. We found evidence for two remarkably different patterns of MHC variation within the genus. While kestrels show a high MHC variation according to the general theory, falcons exhibit an ancestrally low intra- and inter-specific MHC allelic diversity. We provide compelling evidence that this pattern is not caused by the degeneration of functional genes into pseudogenes, the inadvertent analyses of paralogous MHC genes, or the devastating action of genetic drift. Instead, our results strongly support the idea of an evolutionary transition driven and maintained by natural selection from primarily highly variable towards low polymorphic, but functional and expressed, MHC genes with species-specific pathogen-recognition capabilities.

Journal of Evolutionary Biology↗
USGS2011

Heightened exposure to parasites favors the evolution of immunity in brood parasitic cowbirds

Immunologists and evolutionary biologists are interested in how the immune system evolves to fit an ecological niche. We studied the relationship between exposure to parasites and strength of immunity by investigating the response of two species of New World cowbirds (genus Molothrus , Icteridae), obligate brood parasites with contrasting life history strategies, to experimental arboviral infection. The South American shiny cowbird ( M. bonariensis ) is an extreme host - generalist that lays its eggs in the nests of >225 different avian species. The Central American bronzed cowbird ( M. aeneus ) is a relative host - specialist that lays its eggs preferentially in the nests of approximately 12 orioles in a single sister genus. West Nile virus provided a strong challenge and delineated immune differences between these species. The extreme host-generalist shiny cowbird, like the North American host-generalist, the brown-headed cowbird, showed significantly lower viremia to three arboviruses than related icterid species that were not brood parasites. The bronzed cowbird showed intermediate viremia. These findings support the interpretation that repeated exposure to a high diversity of parasites favors the evolution of enhanced immunity in brood parasitic cowbirds and makes them useful models for future studies of innate immunity.

Evolutionary Biology↗
USGS2012

Species differentiation on a dynamic landscape: shifts in metapopulation genetic structure using the chronology of the Hawaiian Archipelago

Species formation during adaptive radiation often occurs in the context of a changing environment. The establishment and arrangement of populations, in space and time, sets up ecological and genetic processes that dictate the rate and pattern of differentiation. Here, we focus on how a dynamic habitat can affect genetic structure, and ultimately, differentiation among populations. We make use of the chronology and geographical history provided by the Hawaiian archipelago to examine the initial stages of population establishment and genetic divergence. We use data from a set of 6 spider lineages that differ in habitat affinities, some preferring low elevation habitats with a longer history of connection, others being more specialized for high elevation and/or wet forest, some with more general habitat affinities. We show that habitat preferences associated with lineages are important in ecological and genetic structuring. Lineages that have more restricted habitat preferences are subject to repeated episodes of isolation and fragmentation as a result of lava flows and vegetation succession. The initial dynamic set up by the landscape translates over time into discrete lineages. Further work is needed to understand how genetic changes interact with a changing set of ecological interactions amongst a shifting mosaic of landscapes to achieve species formation.

Hawai'i↗
USGS2013

Obligate brood parasites show more functionally effective innate immune responses: an eco-immunological hypothesis

Immune adaptations of obligate brood parasites attracted interest when three New World cowbird species (Passeriformes, Icteridae, genus Molothrus) proved unusually resistant to West Nile virus. We have used cowbirds as models to investigate the eco-immunological hypothesis that species in parasite-rich environments characteristically have enhanced immunity as a life history adaptation. As part of an ongoing program to understand the cowbird immune system, in this study we measured degranulation and oxidative burst, two fundamental responses of the innate immune system. Innate immunity provides non-specific, fast-acting defenses against a variety of invading pathogens, and we hypothesized that innate immunity experiences particularly strong selection in cowbirds, because their life history strategy exposes them to diverse novel and unpredictable parasites. We compared the relative effectiveness of degranulation and oxidative burst responses in two cowbird species and one related, non-parasitic species. Both innate immune defenses were significantly more functionally efficient in the two parasitic cowbird species than in the non-parasitic red-winged blackbird (Icteridae, Agelaius phoeniceus). Additionally, both immune defenses were more functionally efficient in the brown-headed cowbird (M. ater), an extreme host-generalist brood parasite, than in the bronzed cowbird (M. aeneus), a moderate host-specialist with lower exposure to other species and their parasites. Thus the relative effectiveness of these two innate immune responses corresponds to the diversity of parasites in the niche of each species and to their relative resistance to WNV. This study is the first use of these two specialized assays in a comparative immunology study of wild avian species.

Evolutionary Biology↗
USGS2024

Phenotypic homogenization and potential fitness constraints following non-native introgression in an endemic sportfish

Introgressive hybridization may lead to contrasting evolutionary outcomes that are difficult to predict since they depend on the fitness effects of endogenous genomic interactions and environmental factors. Conservation of endemic biodiversity may be more effective with require direct measurement of introgressed ancestry and fitness in wild populations, especially for keystone taxa at risk of hybridization following species introductions. We assessed the relationship of non-native ancestry with growth and body condition in the basin-restricted Neosho Bass ( Micropterus velox ; NB), focussing on two streams in the NB native range that are admixed extensively with non-native Smallmouth Bass ( M. dolomieu ; SMB). We quantified the genetic composition of 116 fish from Big Sugar Creek ( N = 46) and Elk River ( N = 70) at 14 microsatellite loci. Using back-calculated total length-at-age estimated from sagittal otoliths, we assessed whether genetic ancestry explained variation in von Bertalanffy growth model parameters, accounting for sex and stream effects. We then assessed the relationship between ancestry and body condition. We found no differences in growth parameters by sex, stream, or ancestry, suggesting phenotypic homogenization which could be mediated by selection on body size. We found a negative correlation between SMB ancestry and condition, including lower condition in Big Sugar Creek, possibly reflecting a trade-off between maximum length and condition with respect to overall fitness. We show that ongoing non-native introgression, which may be augmented by anthropogenic SMB introductions, may attenuate evolutionary differentiation between species and directly influence fitness, possibly having critical implications for long-term persistence and management of adaptive potential in a popular and ecologically important endemic sportfish.

Journal of Evolutionary Biology↗
USGS2007

Food availability affects the maternal transfer of androgens and antibodies into eggs of a colonial seabird

Mothers can improve the quality of their offspring by increasing the level of certain components in their eggs. To examine whether or not mothers increase deposition of such components in eggs as a function of food availability, we food‐supplemented black‐legged kittiwake females (Rissa tridactyla) before and during egg laying and compared deposition of androgens and antibodies into eggs of first and experimentally induced replacement clutches. Food‐supplemented females transferred lower amounts of androgens and antibodies into eggs of induced replacement clutches than did non‐food‐supplemented mothers, whereas first clutches presented no differences between treatments. Our results suggest that when females are in lower condition, they transfer more androgens and antibodies into eggs to facilitate chick development despite potential long‐term costs for juveniles. Females in prime condition may avoid these potential long‐term costs because they can provide their chicks with more and higher quality resources.

Alaska↗
USGS2016

Elevational speciation in action? Restricted gene flow associated with adaptive divergence across an altitudinal gradient

Evolutionary theory predicts that divergent selection pressures across elevational gradients could cause adaptive divergence and reproductive isolation in the process of ecological speciation. Although there is substantial evidence for adaptive divergence across elevation, there is less evidence that this restricts gene flow. Previous work in the boreal chorus frog (Pseudacris maculata) has demonstrated adaptive divergence in morphological, life history and physiological traits across an elevational gradient from approximately 1500–3000 m in the Colorado Front Range, USA. We tested whether this adaptive divergence is associated with restricted gene flow across elevation – as would be expected if incipient speciation were occurring – and, if so, whether behavioural isolation contributes to reproductive isolation. Our analysis of 12 microsatellite loci in 797 frogs from 53 populations revealed restricted gene flow across elevation, even after controlling for geographic distance and topography. Calls also varied significantly across elevation in dominant frequency, pulse number and pulse duration, which was partly, but not entirely, due to variation in body size and temperature across elevation. However, call variation did not result in strong behavioural isolation: in phonotaxis experiments, low-elevation females tended to prefer an average low-elevation call over a high-elevation call, and vice versa for high-elevation females, but this trend was not statistically significant. In summary, our results show that adaptive divergence across elevation restricts gene flow in P. maculata, but the mechanisms for this potential incipient speciation remain open.

Colorado↗
USGS2017

Phylogenetic distribution of a male pheromone that may exploit a nonsexual preference in lampreys

Pheromones are among the most important sexual signals used by organisms throughout the animal kingdom. However, few are identified in vertebrates, leaving the evolutionary mechanisms underlying vertebrate pheromones poorly understood. Pre-existing biases in receivers’ perceptual systems shape visual and auditory signaling systems, but studies on how receiver biases influence the evolution of pheromone communication remain sparse. The lamprey Petromyzon marinus uses a relatively well-understood suite of pheromones and offers a unique opportunity to study the evolution of vertebrate pheromone communication. Previous studies indicate that male signaling with the mating pheromone 3-keto petromyzonol sulfate (3kPZS) may exploit a nonsexual attraction to juvenile-released 3kPZS that guides migration into productive rearing habitat. Here, we infer the distribution of male signaling with 3kPZS using a phylogenetic comparison comprising six of ten genera and two of three families. Our results indicate that only P. marinus and Ichthyomyzon castaneus release 3kPZS at high rates. Olfactory and behavioral assays with P. marinus, I. castaneus and a subset of three other species that do not use 3kPZS as a sexual signal indicate that male signaling might drive the evolution of female adaptations to detect 3kPZS with specific olfactory mechanisms and respond to 3kPZS with targeted attraction relevant during mate search. We postulate that 3kPZS communication evolved independently in I. castaneus and P. marinus , but cannot eliminate the alternative that other species lost 3kPZS communication. Regardless, our results represent a rare macroevolutionary investigation of a vertebrate pheromone and insight into the evolutionary mechanisms underlying pheromone communication.

Journal of Evolutionary Biology↗
USGS2018

Associations of stream geomorphic conditions and prevalence of alternative reproductive tactics among sockeye salmon populations

In many species, males may exhibit alternative life histories to circumvent the costs of intrasexual competition and female courtship. While the evolution and underlying genetic and physiological mechanisms behind alternative reproductive tactics are well studied, there has been less consideration of the ecological factors that regulate their prevalence. Here, we examine six decades of age composition records from thirty‐six populations of sockeye salmon ( Oncorhynchus nerka ) to quantify associations between spawning habitat characteristics and the prevalence of precocious sneakers known as ‘jacks’. Jack prevalence was independent of neutral genetic structure among stream populations, but varied among habitat types and as a function of continuous geomorphic characteristics. Jacks were more common in streams relative to beaches and rivers, and their prevalence was negatively associated with stream width, depth, elevation, slope and area, but positively related to bank cover. Behavioural observations showed that jacks made greater use of banks, wood and shallows than guard males, indicating that their reproductive success depends on the availability of such refuges. Our results emphasize the role of the physical habitat in shaping reproductive tactic frequencies among populations, likely through local adaptation in response to variable fitness expectations under different geomorphic conditions.

Journal of Evolutionary Biology↗