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At least 55 records · Page 3Linked to original sources
USGS2017

Moving forward in circles: Challenges and opportunities in modeling population cycles

Population cycling is a widespread phenomenon, observed across a multitude of taxa in both laboratory and natural conditions. Historically, the theory associated with population cycles was tightly linked to pairwise consumer–resource interactions and studied via deterministic models, but current empirical and theoretical research reveals a much richer basis for ecological cycles. Stochasticity and seasonality can modulate or create cyclic behaviour in non-intuitive ways, the high-dimensionality in ecological systems can profoundly influence cycling, and so can demographic structure and eco-evolutionary dynamics. An inclusive theory for population cycles, ranging from ecosystem-level to demographic modelling, grounded in observational or experimental data, is therefore necessary to better understand observed cyclical patterns. In turn, by gaining better insight into the drivers of population cycles, we can begin to understand the causes of cycle gain and loss, how biodiversity interacts with population cycling, and how to effectively manage wildly fluctuating populations, all of which are growing domains of ecological research.

Ecology Letters↗
USGS2025

Development of high-throughput genomic resources to inform white-tailed deer population and disease management

White-tailed deer ( Odocoileus virginianus ) are the most abundant and widespread cervid in North America. Genetic data are used as a tool to monitor populations and make management decisions for this game species. However, the development and use of genomic tools that can generate a set of markers suitable for longitudinal genomic data collection, whether for management purposes or to study the demographic and evolutionary processes of widely distributed species, have been challenging. This is mainly due to the cost required to fully implement and interpret the data produced. Here, we generated whole genome resequencing data for 44 free-ranging deer from three regions in their central and eastern North American range and identified over 89 million single nucleotide polymorphisms (SNPs). We used a subset of these SNPs to develop two nested SNP tools, a high-density array (702,183 SNPs) and a medium-density array (72,723 SNPs) to support deer and chronic wasting disease (CWD) management and research. SNPs were selected to ensure an even distribution across scaffolds of the reference genome and include SNPs associated with CWD susceptibility. Using genotyping results for 469 deer from 15 states in the US and Mexico generated by the high-density array and 1335 deer from 18 states generated by the medium-density array, we assessed genotyping success across different populations and explored some insights into population structure. These genomic tools offer a standard set of markers that will enable researchers and managers to address important questions related to white-tailed deer and CWD management. Our SNP arrays also offer the opportunity to examine aspects of white-tailed deer ecology and evolutionary history that were previously difficult to address.

Molecular Ecology Resources↗
USGS2024

Evolving wildlife management cultures of governance through Indigenous Knowledges and perspectives

Within governance agencies, academia, and communities alike, there are increasing calls to recognize the value and importance of culture within social-ecological systems and to better implement Indigenous sciences in research, policy, and management. Efforts thus far have raised questions about the best ethical practices to do so. Engaging with plural worldviews and perspectives on their own terms reflects cultural evolutionary processes driving paradigm shifts in 3 fundamental areas of natural resource management: conceptualizations of natural resources and ecosystems, processes of public participation and governance, and relationships with Indigenous Peoples and communities with differing worldviews. We broadly describe evolution toward these paradigm shifts in fish and wildlife management. We then use 3 case studies to illustrate the ongoing cultural evolution of relationships between wildlife management and Indigenous practices within specific historical and social-ecological contexts and reflect on common barriers to appropriately engaging with Indigenous paradigms and lifeways. Our case studies highlight 3 priorities that can assist the field of wildlife management in achieving the changes necessary to bridge incommensurable worldviews: acknowledging and reconciling historical legacies and their continued power dynamics as part of social-ecological systems, establishing governance arrangements that move beyond attempts to extract cultural information from communities to integrate Indigenous Knowledges into dominant management paradigms, and engaging in critical reflexivity and reciprocal, accountable relationship building. Implementing these changes will take time and a commitment to processes that may initially feel uncomfortable and unfamiliar but have potential to be transformative. Ethical and culturally appropriate methods to include plural and multivocal perspectives and worldviews on their own terms are needed to transform wildlife management to achieve more effective and just management outcomes for all.

Journal of Wildlife Management↗
USGS2023

Evolutionary fire ecology: An historical account and future directions

The idea that fire acts as an evolutionary force contributing to shaping species traits started a century ago, but had not been widely recognized until very recently. Among the first to realize this force were E dward B . Poulton, R. D ale Guthrie, and E dwin V . Komarek in animals and W illis L . Jepson, W alter W . Hough, T om M . Harris, P hilip V . Wells, and R obert W . Mutch in plants. They were all ahead of their time in their evolutionary thinking. Since then, evolutionary fire ecology has percolated very slowly into the mainstream ecology and evolutionary biology; in fact, this topic is still seldom mentioned in textbooks of ecology or evolution. Currently, there is plenty of evidence suggesting that we cannot understand the biodiversity of our planet without considering the key evolutionary role of fire. But there is still research to be done in order to fully understand fire's contribution to species evolution and to predicting species responses to rapid global changes.

BioScience↗
USGS2003

Isolation and characterization of novel waterfowl microsatellite loci: Cross-species comparisons and research applications

Waterfowl constitute an ecologically diverse group which are the subject of extensive research (e.g. see reviews in Batt et al . 1992), and are intensively managed (Nichols et al .1995). Genetic studies utilizing allozyme electrophoresis and mitochondrial (mt)DNA have provided valuable information on waterfowl ecology and evolutionary history (Cooke & Buckley 1987). However, highly variable molecular genetic markers (e.g. multilocus minisatellites; Triggs et al. 1992) have not generally been identified for this group.

Molecular Ecology↗
USGS2016

The bee microbiome: Impact on bee health and model for evolution and ecology of host-microbe interactions

As pollinators, bees are cornerstones for terrestrial ecosystem stability and key components in agricultural productivity. All animals, including bees, are associated with a diverse community of microbes, commonly referred to as the microbiome. The bee microbiome is likely to be a crucial factor affecting host health. However, with the exception of a few pathogens, the impacts of most members of the bee microbiome on host health are poorly understood. Further, the evolutionary and ecological forces that shape and change the microbiome are unclear. Here, we discuss recent progress in our understanding of the bee microbiome, and we present challenges associated with its investigation. We conclude that global coordination of research efforts is needed to fully understand the complex and highly dynamic nature of the interplay between the bee microbiome, its host, and the environment. High-throughput sequencing technologies are ideal for exploring complex biological systems, including host-microbe interactions. To maximize their value and to improve assessment of the factors affecting bee health, sequence data should be archived, curated, and analyzed in ways that promote the synthesis of different studies. To this end, the BeeBiome consortium aims to develop an online database which would provide reference sequences, archive metadata, and host analytical resources. The goal would be to support applied and fundamental research on bees and their associated microbes and to provide a collaborative framework for sharing primary data from different research programs, thus furthering our understanding of the bee microbiome and its impact on pollinator health.

mBio↗
USGS2022

Site fidelity as a maladaptive behavior in the Anthropocene

Site fidelity, or the behavior of returning to previously visited locations, has been observed across taxa and ecosystems. By developing familiarity with a particular location, site fidelity provides a range of benefits and is advantageous in stable or predictable environments. However, the Anthropocene is characterized by rates of environmental change that outpace the evolutionary history of extant taxa, which can result in site fidelity becoming maladaptive. Here we outline the theoretical underpinnings for maladaptive site fidelity and synthesize empirical research supporting its occurrence, and examine it in the context of a related concept, ecological traps, whereby organisms exhibit maladaptive behavior in habitat selection. We then discuss adaptive mechanisms that may enable species with site fidelity to continue to persist in the Anthropocene. With ongoing environmental change, researchers and practitioners should expect fidelity-induced ecological traps to become more common, and initiate projects to identify and understand their origins. Such knowledge will help conserve the widespread and ecologically important behavior of site fidelity.

Frontiers in Ecology and the Environment↗
USGS2017

Molecular phylogeny of the Nearctic and Mesoamerican freshwater mussel genus Megalonaias

Megalonaias is the most geographically widespread genus of the subfamily Ambleminae and is distributed across much of the eastern half of North America, from Minnesota to Nicaragua. Despite the large geographic distribution, the species-level diversity of Megalonaias is quite depauperate (2 spp.), suggesting the genus may not be constrained by the same physical, ecological, or physiological barriers that limit dispersal in many other amblemines. However, this hypothesis is contingent on the assumption that the current taxonomy of Megalonaias accurately reflects its evolutionary history, which remains incompletely understood due to the marginalization of Mesoamerican populations in systematic research. Using one mitochondrial (COI ) and one nuclear marker ( ITS1 ) sequenced from 41 individuals distributed across both the Nearctic and Mesoamerican ecoregions, we set out to better understand the species boundaries and genetic diversity within Megalonaias . The reconstructed molecular phylogeny and the observed genetic diversity suggests that Megalonaias is a monotypic genus and that Megalonaias nickliniana , currently considered a federally endangered species, is not a valid species. These results are discussed in the context of their systematic and conservation implications, as well as how the unusual life history strategy of Megalonaias may be influencing its molecular diversity.

Hydrobiologia↗
USGS2024

The cost of self-defense: Browsing effects in the rare plant species Salix arizonica

Coevolution between plants and their animal predators has led to diverse defensive adaptations. Multiple theories of defense propose that there are resource allocation costs associated with producing chemical defenses. One leading hypothesis, optimal defense theory (ODT), suggests that natural selection will result in the allocation of resources to defenses that optimize the cost-to-benefit ratio between defense and other functional processes. The population decline of the rare subalpine wetland species, Arizona willow ( Salix arizonica ), has been attributed to various biotic and abiotic factors, with browsing from wild and domestic ungulates as a significant concern for at least three decades. In a field experiment using natural populations, we compare the relationship between phytochemical defense and height in Arizona willows with and without long-term protection from browsing via browse exclosures. Consistent with the predictions of ODT, individuals with physical protection from ungulate browsing for multiple years had significantly lower phenolic glycoside (PG) concentrations and increased plant height compared to unprotected individuals. A similar pattern was found across all individuals, whereby total PG concentration and height were negatively correlated. In a short-term experiment in natural populations, changes in levels of defense were not observed when plants received protection for only one growing season. The contrasting pattern of defense plasticity in response to long-term versus short-term physical protection suggests a differential plastic response in this long-lived species. Delayed reduction in PG concentration may serve as a benefit to avoid mismatches between environmental cues and responses. Our research sheds light on the intricate dynamics between plant-defense strategies, environmental pressures, and evolutionary adaptations in shaping plant–browser interactions.

Arizona, Colorado, New Mexico, Utah↗
USGS2021

Recovery and analysis of ancient beetle DNA from subfossil packrat middens using high-throughput sequencing

The study of ancient DNA is revolutionizing our understanding of paleo-ecology and the evolutionary history of species. Insects are essential components in many ecosystems and constitute the most diverse group of animals. Yet they are largely neglected in ancient DNA studies. We report the results of the first targeted investigation of insect ancient DNA to positively identify subfossil insects to species, which includes the recovery of endogenous content from samples as old as ~ 34,355 ybp. Potential inhibitors currently limiting widespread research on insect ancient DNA are discussed, including the lack of closely related genomic reference sequences (decreased mapping efficiency) and the need for more extensive collaborations with insect taxonomists. The advantages of insect-based studies are also highlighted, especially in the context of understanding past climate change. In this regard, insect remains from ancient packrat middens are a rich and largely uninvestigated resource for exploring paleo-ecology and species dynamics over time.

Scientific Reports↗
USGS2023

Biodiversity connections—‘ties that bind’

Connectivity is a foundational concept in ecology and conservation and was the organising theme for the 2022 Annual Meeting of the Southeastern Fishes Council, a professional organisation dedicated to the study and conservation of freshwater fishes native to the southeast region of the United States (US). We introduce a Special Contribution of six papers selected from presentations at that meeting that illustrate perspectives on connections created by fish migration and dispersal, evolved life histories and habitat affinities and interspecific facilitation. Although focused on streams of the southeast US, each of these topics is broadly relevant to freshwater fish conservation, particularly with respect to causes and consequences of migratory fish depletion, population fragmentation and species declines. Many other connections relevant to the ecology and conservation of freshwater fishes remain relatively unexplored but could substantively advance conservation. We highlight the potential that species evolutionary histories, that is connections through time, reconstructed using species distributions and phylogenies may improve predictions of species responses to environmental change. Identifying species interdependencies, including undiscovered interactions that support survival or reproduction, could provide insights into how species losses may cascade as aquatic communities unravel. Finally, efforts to elucidate diverse connections between people and freshwater biodiversity, particularly where fisheries are historic and streams mostly go unnoticed, may prove essential to building public support for conservation measures. A research agenda anchored on ‘biodiversity connections’ has the potential to advance ecological understanding and public engagement, elements essential to conserving freshwater fishes.

Ecology of Freshwater Fish↗
USGS2022

The Pacific as the world’s greatest theater of bird migration: Extreme flights spark questions about physiological capabilities, behavior, and the evolution of migratory pathways

The Pacific Basin, by virtue of its vastness and its complex aeroscape, provides unique opportunities to address questions about the behavioral and physiological capabilities and mechanisms through which birds can complete spectacular flights. No longer is the Pacific seen just as a formidable barrier between terrestrial habitats in the north and the south, but rather as a gateway for specialized species, such as shorebirds, to make a living on hemispherically distributed seasonal resources. This recent change in perspective is dramatic, and the research that underpins it has presented new opportunities to learn about phenomena that often challenge a sense of normal. Ancient Polynesians were aware of the seasonal passage of shorebirds and other landbirds over the Pacific Ocean, incorporating these observations into their navigational “tool kit” as they explored and colonized the Pacific. Some ten centuries later, systematic visual observations and tracking technology have revealed much about movement of these shorebirds, especially the enormity of their individual nonstop flights. This invites a broad suite of questions, often requiring comparative studies with bird migration across other ocean basins, or across continents. For example, how do birds manage many days of nonstop exercise apparently without sleep? What mechanisms explain birds acting as if they possess a Global Positioning System? How do such extreme migrations evolve? Through advances in both theory and tracking technology, biologists are poised to greatly expand the horizons of movement ecology as we know it. In this integrative review, we present a series of intriguing questions about trans-Pacific migrant shorebirds and summarize recent advances in knowledge about migratory behavior operating at temporal scales ranging from immediate decisions during a single flight, to adaptive learning throughout a lifetime, to evolutionary development of migratory pathways. Recent advances in this realm should stimulate future research across the globe and across a broad array of disciplines.

Ornithology↗
USGS2021

The ecology and evolution of synchronized reproduction in long-lived plants

Populations of many long-lived plants exhibit spatially synchronized seed production that varies extensively over time, so that seed production in some years is much higher than on average, while in others, it is much lower or absent. This phenomenon termed masting or mast seeding has important consequences for plant reproductive success, ecosystem dynamics and plant–human interactions. Inspired by recent advances in the field, this special issue presents a series of articles that advance the current understanding of the ecology and evolution of masting. To provide a broad overview, we reflect on the state-of-the-art of masting research in terms of underlying proximate mechanisms, ontogeny, adaptations, phylogeny and applications to conservation. While the mechanistic drivers and fitness consequences of masting have received most attention, the evolutionary history, ontogenetic trajectory and applications to plant–human interactions are poorly understood. With increased availability of long-term datasets across broader geographical and taxonomic scales, as well as advances in molecular approaches, we expect that many mysteries of masting will be solved soon. The increased understanding of this global phenomenon will provide the foundation for predictive modelling of seed crops, which will improve our ability to manage forests and agricultural fruit and nut crops in the Anthropocene.

Philosophical Transactions of the Royal Society B:↗
USGS2017

Correlates of immune defenses in golden eagle nestlings

An individual's investment in constitutive immune defenses depends on both intrinsic and extrinsic factors. We examined how Leucocytozoon parasite presence, body condition (scaled mass), heterophil-to-lymphocyte (H:L) ratio, sex, and age affected immune defenses in golden eagle ( Aquila chrysaetos) nestlings from three regions: California, Oregon, and Idaho. We quantified hemolytic-complement activity and bacterial killing ability, two measures of constitutive immunity. Body condition and age did not affect immune defenses. However, eagles with lower H:L ratios had lower complement activity, corroborating other findings that animals in better condition sometimes invest less in constitutive immunity. In addition, eagles with Leucocytozoon infections had higher concentrations of circulating complement proteins but not elevated opsonizing proteins for all microbes, and eagles from Oregon had significantly higher constitutive immunity than those from California or Idaho. We posit that Oregon eagles might have elevated immune defenses because they are exposed to more endoparasites than eagles from California or Idaho, and our results confirmed that the OR region has the highest rate of Leucocytozoon infections. Our study examined immune function in a free-living, long-lived raptor species, whereas most avian ecoimmunological research focuses on passerines. Thus, our research informs a broad perspective regarding the evolutionary and environmental pressures on immune function in birds.

California, Idaho, Oregon↗
USGS2024

Documentation of a probable spawning run of cisco Coregonus artedi in the Spanish River, Ontario, Canada

Coregonines were historically diverse and abundant in the Laurentian Great Lakes but declined throughout the 19th and 20th centuries due to multiple factors, including overfishing, habitat degradation, and interactions with invasive species. Great Lakes fishery managers are now working to restore coregonines across the basin. An important aspect of restoration efforts is the identification of key habitats, such as spawning habitats. Our understanding of the extent and diversity of coregonine spawning habitats in the Great Lakes is limited. Historical accounts suggest some cisco Coregonus artedi migrated to tributaries to spawn, but contemporary runs have not been reported. Moreover, cisco display considerable phenotypic variation, with different “forms” often occupying specific habitats or regions. We provide evidence for a previously undocumented spawning run of cisco in the Spanish River, a tributary to the North Channel of Lake Huron. We captured 31 mature and ripe fish (25 males, 6 females) approximately 52 km upstream of the river mouth on 15–16 November 2022. The fish ranged in age from 3-9 yr and total length from 287-394 mm. Of these 31 individuals, 27 were morphologically similar to C. artedi manitoulinus , a subspecies of cisco found in the North Channel; however, four individuals more closely resembled cisco captured in other areas of Lake Huron. These findings represent the best evidence of tributary spawning by cisco since the 1880s, and they have important implications for coregonine conservation and restoration efforts. Ongoing work aims to augment our understanding of the ecological and evolutionary importance of this population.

Ontario↗
USGS2010

The Origins of C4 Grasslands: Integrating Evolutionary and Ecosystem Science

The evolution of the C 4 photosynthetic pathway from the ancestral C 3 pathway in grasses led to the establishment of grasslands in warm climates during the Late Miocene (8 to 3 million years ago). This was a major event in plant evolutionary history, and their high rates of foliage production sustained high levels of herbivore consumption. The past decade has seen significant advances in understanding C 4 grassland ecosystem ecology, and now a wealth of data on the geological history of these ecosystems has accumulated and the phylogeny of grasses is much better known. Edwards et al. (p. 587) review this multidisciplinary research area and attempt to synthesize emerging knowledge about the evolution of grass species within the context of plant and ecosystem ecology.

Science↗
USGS2009

Presettlement and modern disturbance regimes in coast redwood forests: Implications for the conservation of old-growth stands

Coast redwood ( Sequoia sempervirens ), a western North American conifer of ancient lineage, has a paradoxical combination of late-successional characteristics and strong adaptations to disturbance. Despite its shade tolerance and heavy dominance of the canopy on many sites, redwood saplings are uncommon in upland old-growth stands. Information needed to ensure the conservation of old-growth redwood forests has been limited. In this review paper, we integrate evidence on redwood biology with data on the historic and modern disturbance regimes to help clarify the degree to which key attributes of redwood forests may have been dependent upon periodic disturbance. Available evidence suggests that episodes of fire, flooding, and slope failure prior to European settlement were frequent but predominantly of low to moderate severity and extent, resulting in broadly uneven-aged forests. The majority of fires prior to European settlement were apparently of human origin. Frequency and severity of the major disturbance agents have been radically changed in modern times. Fires have been largely excluded, and flooding has been altered in ways that have often been detrimental to old-growth redwoods on alluvial terraces. However, because of the apparent anthropogenic origin of most presettlement fires, the long-term evolutionary role of fire for coast redwood is ecologically ambiguous. With fire exclusion, redwood possibly could be displaced to some extent on upland sites by increasing abundance of fire-sensitive competitors. Alternatively, redwood may be able to maintain dominance by vegetative sprouting and new seedling establishment on root-wad mounds, fallen logs, and on soil exposed by slope failure. Future research priorities are suggested that will help resolve some of the current ambiguities.

Forest Ecology and Management↗
USGS2016

The conservation genetics juggling act: Integrating genetics and ecology, science and policy

The field of conservation genetics, when properly implemented, is a constant juggling act integrating molecular genetics, ecology, and demography with applied aspects concerning managing declining species or implementing conservation laws and policies. This young field has grown substantially since the 1980’s following development of the polymerase chain reaction and now into the genomics era. Our lab has “grown up” with the field, having worked on these issues for over three decades. Our multi-disciplinary approach entails understanding the behavior and ecology of species as well as the underlying processes that contribute to genetic viability. Taking this holistic approach provides a comprehensive understanding of factors that influence species persistence and evolutionary potential while considering annual challenges that occur throughout their life cycle. As a federal lab, we are often addressing the needs of the U.S. Fish and Wildlife Service in their efforts to list, de-list or recover species. Nevertheless, there remains an overall communication gap between research geneticists and biologists who are charged with implementing their results. Therefore, we outline the need for a National Center for Small Population Biology to ameliorate this problem and provide organizations charged with making status decisions firmer ground from which to make their critical decisions.

Evolutionary Applications↗