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At least 55 records · Page 3Linked to original sources

Stakeholders' priorities for management of a restored elk (Cervus canadensis) population in northeast Minnesota

Wildlife reintroduction projects are an important tool for restoring traditional wildlife heritage, increasing species diversity, providing subsistence and sport hunting and other recreational opportunities, and assisting ecosystem adaption to future climate change. In Minnesota, the Fond du Lac Band of Lake Superior Chippewa and some conservationists advocate for the expansion of existing elk range to other parts of the state. For reintroduction projects to be successful, it is helpful if managers understand stakeholders' preferences for management objectives. We used best-worst scaling (BWS) to assess residents' preferences for management objective alternatives. The University of Minnesota, in collaboration with the Fond du Lac Band of Lake Superior Chippewa and the Rocky Mountain Elk Foundation, conducted a mail-back questionnaire of landowners ( n = 4500) and the general public ( n = 4000) in northeastern Minnesota to determine their attitudes toward elk reintroduction. Results suggest that the most preferred objectives were minimizing negative impacts on existing wildlife populations and reintroducing native species. In contrast, the least important objectives were related to providing elk viewing opportunities or maximizing economic opportunities through elk-related tourism. These findings help inform management objectives related to the reintroduction proposal, provide insight to minimize potential conflict and help develop future communication material related to elk reintroduction.

Minnesota

Biogeography of freshwater mussels (Bivalvia: Unionida) in Texas and implications on conservation biology

Aim Biogeography seeks to identify and explain the spatial distributions of species and has become an important tool used by conservationists to protect and manage aquatic organisms. Texas, located in the southwestern United States, is home to 52 species of freshwater mussels, 9 of which are endemic to Texas and 7 that are endemic to Texas and neighboring states or countries. There have been two major attempts to classify this fauna into biogeographical provinces; however, both efforts relied on limited distribution information and outdated taxonomy. To address both issues, we set out to delineate biogeographic provinces for freshwater mussels in Texas by using a comprehensive distributional dataset of >28,000 records and molecular information. Location Southwestern United States. Methods We compiled community and molecular data for 48 of the 52 freshwater mussel species that occur in Texas. We performed algorithmic hierarchal cluster analysis (HCA) and nonmetric multidimensional scaling (NMDS) based on Euclidean distance to identify biogeographic groupings. We conducted a similar analysis using molecular sequence data for our target species. Results Based on the results from community and molecular data, we identified seven biogeographic provinces for freshwater mussels in Texas: Great Plains, Mississippi Embayment, Sabine-Neches, Trinity-San Jacinto, Central Texas, Rio Grande and Coastal. However, the Coastal and Great Plains provinces were not included in our analysis and were recognized based on previous work. Main conclusions Our approach integrating community and molecular datasets provides a comprehensive assessment of the biogeography of freshwater mussels in Texas, which serves as a model for future biogeographic studies. Our findings also shed light on the ecological, evolutionary and geologic processes shaping freshwater mussel communities in Texas, which is important for the conservation of remaining biodiversity in the state.

Texas

Considering multiecosystem trade-offs is critical when leveraging systematic conservation planning for restoration

Conservationists are increasingly leveraging systematic conservation planning (SCP) to inform restoration actions that enhance biodiversity. However, restoration frequently drives ecological transformations at local scales, potentially resulting in trade-offs among wildlife species and communities. The Conservation Interactions Principle (CIP), coined more than 15 years ago, cautions SCP practitioners regarding the importance of jointly and fully evaluating conservation outcomes across the landscape over long timeframes. However, SCP efforts that guide landscape restoration have inadequately addressed the CIP by failing to tabulate the full value of the current ecological state. The increased application of SCP to inform restoration, reliance on increasingly small areas to sustain at-risk species and ecological communities, ineffective considerations for the changing climate, and increasing numbers of at-risk species, are collectively intensifying the need to consider unintended consequences when prioritizing sites for restoration. Improper incorporation of the CIP in SCP may result in inefficient use of conservation resources through opportunity costs and/or conservation actions that counteract one another. We suggest SCP practitioners can avoid these consequences through a more detailed accounting of the current ecological benefits to better address the CIP when conducting restoration planning. Specifically, forming interdisciplinary teams with expertise in the current and desired ecosystem states at candidate conservation sites; improving data availability; modeling and computational advancements; and applying structured decision-making approaches can all improve the integration of the CIP in SCP efforts. Improved trade-off assessment, spanning multiple ecosystems or states, can facilitate efficient, proactive, and coordinated SCP applications across space and time. In doing so, SCP can effectively guide the siting of restoration actions capable of promoting the full suite of biodiversity in a region.

Global Change Biology

A global analysis of traits predicting species sensitivity to habitat fragmentation

Aim Elucidating patterns in species responses to habitat fragmentation is an important focus of ecology and conservation, but studies are often geographically restricted, taxonomically narrow or use indirect measures of species vulnerability. We investigated predictors of species presence after fragmentation using data from studies around the world that included all four terrestrial vertebrate classes, thus allowing direct inter-taxonomic comparison. Location World-wide. Methods We used generalized linear mixed-effect models in an information theoretic framework to assess the factors that explained species presence in remnant habitat patches (3342 patches; 1559 species, mostly birds; and 65,695 records of patch-specific presence–absence). We developed a novel metric of fragmentation sensitivity, defined as the maximum rate of change in probability of presence with changing patch size (‘Peak Change’), to distinguish between general rarity on the landscape and sensitivity to fragmentation per se. Results Size of remnant habitat patches was the most important driver of species presence. Across all classes, habitat specialists, carnivores and larger species had a lower probability of presence, and those effects were substantially modified by interactions. Sensitivity to fragmentation (measured by Peak Change) was influenced primarily by habitat type and specialization, but also by fecundity, life span and body mass. Reptiles were more sensitive than other classes. Grassland species had a lower probability of presence, though sample size was relatively small, but forest and shrubland species were more sensitive. Main conclusions Habitat relationships were more important than life-history characteristics in predicting the effects of fragmentation. Habitat specialization increased sensitivity to fragmentation and interacted with class and habitat type; forest specialists and habitat-specific reptiles were particularly sensitive to fragmentation. Our results suggest that when conservationists are faced with disturbances that could fragment habitat they should pay particular attention to specialists, particularly reptiles. Further, our results highlight that the probability of presence in fragmented landscapes and true sensitivity to fragmentation are predicted by different factors.

Global Ecology and Biogeography

Off-road vehicles affect nesting behaviour and reproductive success of American Oystercatchers Haematopus palliatus

As human populations and associated development increase, interactions between humans and wildlife are occurring with greater frequency. The effects of these interactions, particularly on species whose populations are declining, are of great interest to ecologists, conservationists, land managers and natural resource policy-makers. The American Oystercatcher Haematopus palliatus , a species of conservation concern in the USA, nests on coastal beaches subject to various forms of anthropogenic disturbance, including aircraft overflights, off-road vehicles and pedestrians. This study assessed the effects of these human disturbances on the incubation behaviour and reproductive success of nesting American Oystercatchers at Cape Lookout National Seashore, on the Atlantic coast of the USA. We expanded on-going monitoring of Oystercatchers at Cape Lookout National Seashore by supplementing periodic visual observations with continuous 24-h video and audio recording at nests. Aircraft overflights were not associated with changes in Oystercatcher incubation behaviour, and we found no evidence that aircraft overflights influenced Oystercatcher reproductive success. However, Oystercatchers were on their nests significantly less often during off-road vehicle and pedestrian events than they were during control periods before the events, and an increase in the number of off-road vehicles passing a nest during incubation was consistently associated with significant reductions in daily nest survival (6% decrease in daily nest survival for a one-vehicle increase in the average number of vehicles passing a nest each day; odds ratio = 0.94; 95% confidence interval (CI) 0.90, 0.98) and hatching success (12% decrease in hatching success for a one-vehicle increase in the average number of vehicles passing a nest each day; odds ratio = 0.88; 95% CI 0.76, 0.97). Management of vehicles and pedestrians in areas of Oystercatcher breeding is important for the conservation of American Oystercatchers.

International Journal of Avian Science

Desert bird associations with broad-scale boundary length: Applications in avian conservation

1. Current understanding regarding the effects of boundaries on bird communities has originated largely from studies of forest-non-forest boundaries in mesic systems. To assess whether broad-scale boundary length can affect bird community structure in deserts, and to identify patterns and predictors of species' associations useful in avian conservation, we studied relations between birds and boundary-length variables in Chihuahuan Desert landscapes. Operationally, a boundary was the border between two adjoining land covers, and broad-scale boundary length was the total length of such borders in a large area. 2. Within 2-km radius areas, we measured six boundary-length variables. We analysed bird-boundary relations for 26 species, tested for assemblage-level patterns in species' associations with boundary-length variables, and assessed whether body size, dispersal ability and cowbird-host status were correlates of these associations. 3. The abundances or occurrences of a significant majority of species were associated with boundary-length variables, and similar numbers of species were related positively and negatively to boundary-length variables. 4. Disproportionately small numbers of species were correlated with total boundary length, land-cover boundary length and shrubland-grassland boundary length (variables responsible for large proportions of boundary length). Disproportionately large numbers of species were correlated with roadside boundary length and riparian vegetation-grassland boundary length (variables responsible for small proportions of boundary length). Roadside boundary length was associated (positively and negatively) with the most species. 5. Species' associations with boundary-length variables were not correlated with body size, dispersal ability or cowbird-host status. 6. Synthesis and applications. For the species we studied, conservationists can use the regressions we report as working models to anticipate influences of boundary-length changes on bird abundance and occurrence, and to assess avifaunal composition for areas under consideration for protection. Boundary-length variables associated with a disproportionate or large number of species can be used as foci for landscape management. Assessing the underlying causes of bird-boundary relations may improve the prediction accuracy of associated models. We therefore advocate local- and broad-scale manipulative experiments involving the boundary types with which species were correlated, as indicated by the regressions. ?? 2008 The Authors.

Journal of Applied Ecology

Hierarchical spatial models for predicting pygmy rabbit distribution and relative abundance

Conservationists routinely use species distribution models to plan conservation, restoration and development actions, while ecologists use them to infer process from pattern. These models tend to work well for common or easily observable species, but are of limited utility for rare and cryptic species. This may be because honest accounting of known observation bias and spatial autocorrelation are rarely included, thereby limiting statistical inference of resulting distribution maps. We specified and implemented a spatially explicit Bayesian hierarchical model for a cryptic mammal species (pygmy rabbit Brachylagus idahoensis). Our approach used two levels of indirect sign that are naturally hierarchical (burrows and faecal pellets) to build a model that allows for inference on regression coefficients as well as spatially explicit model parameters. We also produced maps of rabbit distribution (occupied burrows) and relative abundance (number of burrows expected to be occupied by pygmy rabbits). The model demonstrated statistically rigorous spatial prediction by including spatial autocorrelation and measurement uncertainty. We demonstrated flexibility of our modelling framework by depicting probabilistic distribution predictions using different assumptions of pygmy rabbit habitat requirements. Spatial representations of the variance of posterior predictive distributions were obtained to evaluate heterogeneity in model fit across the spatial domain. Leave-one-out cross-validation was conducted to evaluate the overall model fit. Synthesis and applications. Our method draws on the strengths of previous work, thereby bridging and extending two active areas of ecological research: species distribution models and multi-state occupancy modelling. Our framework can be extended to encompass both larger extents and other species for which direct estimation of abundance is difficult. ?? 2010 The Authors. Journal compilation ?? 2010 British Ecological Society.

Journal of Applied Ecology

Historic distribution and challenges to bison recovery in the northern Chihuahuan Desert

Ecologists and conservationists have long assumed that large grazers, including bison ( Bison bison ), did not occur in post-Pleistocene southwestern North America. This perception has been influential in framing the debate over conservation and land use in the northern Chihuahuan Desert. The lack of an evolutionary history of large grazers is being used to challenge the validity of ranching as a conservation strategy and to limit the protection and reintroduction of bison as a significant component of desert grassland ecosystems. Archeological records and historical accounts from Mexican archives from AD 700 to the 19th century document that the historic range of the bison included northern Mexico and adjoining areas in the United States. The Janos-Hidalgo bison herd, one of the few free-ranging bison herds in North America, has moved between Chihuahua, Mexico, and New Mexico, United States, since at least the 1920s. The persistence of this cross-border bison herd in Chihuahuan Desert grasslands and shrublands demonstrates that the species can persist in desert landscapes. Additional lines of evidence include the existence of grazing-adapted grasslands and the results of experimental studies that document declines in vegetation density and diversity following the removal of large grazers. The Janos-Hidalgo herd was formed with animals from various sources at the turn of the 19th century. Yet the future of the herd is compromised by differing perceptions of the ecological and evolutionary role of bison in the Desert Grasslands of North America. In Mexico they are considered native and are protected by federal law, whereas in New Mexico, they are considered non-native livestock and therefore lack conservation status or federal protection. Evidence written in Spanish of the presence of bison south of the accepted range and evidence from the disciplines of archaeology and history illustrate how differences in language and academic disciplines, in addition to international boundaries, have acted as barriers in shaping comprehensive approaches to conservation. Bison recovery in the region depends on binational cooperation.

Arizona, Chihuahua, Coahuila, Durango, New Mexico,

Book review: The man who saved the whooping crane: The Robert Porter Allen story

Kathleen Kaska has done a remarkable job of capturing the life of Robert Porter Allen, truly one of the premier biologist/conservationists of the twentieth century. Allen, born in 1905, grew up reading outdoor adventure books and playing in the woods of northern Pennsylvania with his brother. At a young age, he was encouraged to join the Junior Audubon club and his passion for ornithology soon crystallized. He attended Lafayette College to study ornithology, but he was disinterested in academics and fared poorly. He dropped out after two years and joined the Merchant Marines. Not an auspicious beginning for such a highly respected scientist and conservationist! Soon, however, he landed a librarian job with Audubon and his diligence, acumen, and communication skills allowed him to take more and more responsibilities. He became one of the youngest Audubon sanctuary directors ever appointed, and he was also able to secure a fellowship through Cornell to work on Roseate Spoonbills ( Platalea ajaja ). Audubon later appointed him to lead their Whooping Crane ( Grus americana ) studies. Review info: The Man Who Saved the Whooping Crane. By Kathleen Kaska, 2012. ISBN: 978-0813040240, 256 pp.

Journal of Field Ornithology

Mapping out a future for ungulate migrations

Migration of ungulates (hooved mammals) is a fundamental ecological process that promotes abundant herds, whose effects cascade up and down terrestrial food webs. Migratory ungulates provide the prey base that maintains large carnivore and scavenger populations and underpins terrestrial biodiversity (fig. S1). When ungulates move in large aggregations, their hooves, feces, and urine create conditions that facilitate distinct biotic communities. The migrations of ungulates have sustained humans for thousands of years, forming tight cultural links among Indigenous people and local communities. Yet ungulate migrations are disappearing at an alarming rate ( 1 ). Efforts by wildlife managers and conservationists are thwarted by a singular challenge: Most ungulate migrations have never been mapped in sufficient detail to guide effective conservation. Without a strategic and collaborative effort, many of the world's great migrations will continue to be truncated, severed, or lost in the coming decades. Fortunately, a combination of animal tracking datasets, historical records, and local and Indigenous knowledge can form the basis for a global atlas of migrations, designed to support conservation action and policy at local, national, and international levels.

Science

Testing theoretical metapopulation conditions with genotypic data from Boreal Chorus Frogs (Pseudacris maculata)

The metapopulation concept has far-reaching implications in ecology and conservation biology. Hanski’s criteria operationally define metapopulations, yet testing them is hindered by logistical and financial constraints inherent to the collection of long-term demographic data. Hence, ecologists and conservationists often assume metapopulation existence for dispersal-limited species that occupy patchy habitats. To advance understanding of metapopulation theory and improve conservation of metapopulations, we used population and landscape genetic tools to develop a methodological framework for evaluating Hanski’s criteria. We used genotypic data (11 microsatellite loci) from a purported metapopulation of Boreal Chorus Frogs ( Pseudacris maculata (Agassiz, 1850)) in Colorado, U.S.A., to test Hanski’s four criteria. We found support for each criterion: (1) significant genetic differentiation between wetlands, suggesting distinct breeding populations; (2) wetlands had small effective population sizes and recent bottlenecks, suggesting populations do not experience long-term persistence; (3) population graphs provided evidence of gene flow between patches, indicating potential for recolonization; and (4) multiscale bottleneck analyses suggest asynchrony, indicating that simultaneous extinction of all populations was unlikely. Our methodological framework provides a logistically and financially feasible alternative to long-term demographic data for identifying amphibian metapopulations.

Colorado

A comparison of methods for the long-term harness-based attachment of radio-transmitters to juvenile Japanese quail (Coturnix japonica)

Background While the period from fledging through first breeding for waterbird species such as terns (e.g., genus Sterna, Sternula) is of great interest to researchers and conservationists, this period remains understudied due in large part to the difficulty of marking growing juveniles with radio transmitters that remain attached for extended periods. Methods In an effort to facilitate such research, we examined the impact of various combinations of harness types (backpack, leg-loop, and 3D-printed harnesses), harness materials (Automotive ribbon, Elastic cord, and PFTE ribbon), and transmitter types (center-weighted and rear-weighted) on a surrogate for juvenile terns, 28-day-old Japanese quail ( Coturnix japonica; selected due to similarities in adult mass and downy feathering of juveniles ), in a 30-day experiment. We monitored for abrasion at points of contact and tag gap issues via daily exams while also recording mass and wing cord as indices of growth. This study was designed to serve as an initial examination of the impacts of marking on the growth and development of young birds and does not account for any impacts of tags on movement or behavior. Results While we found that treatment (the specific combination of the transmitter type, harness type, and harness material) had no impact on bird growth relative to unmarked control birds ( P ≥ 0.05), we did observe differences in abrasion and tag gap between treatments ( P ≤ 0.05). Our results suggest that leg-loop harnesses constructed from elastic cord and backpack harnesses from PFTE ribbon are suitable options for long-term attachment to growing juveniles. Conversely, we found that automotive ribbon led to extensive abrasion with these small-bodied birds, and that elastic cord induced blisters when used to make a backpack harness. Conclusions While these results indicate that long-term tagging of juvenile birds is possible with limited impacts on growth, this work does not preclude the need for small-scale studies with individual species. Instead, we hope this provides an informed starting point for further exploration of this topic.

Animal Biotelemetry

Evaluating the potential effectiveness of compensatory mitigation strategies for marine bycatch

Conservationists are continually seeking new strategies to reverse population declines and safeguard against species extinctions. Here we evaluate the potential efficacy of a recently proposed approach to offset a major anthropogenic threat to many marine vertebrates: incidental bycatch in commercial fisheries operations. This new approach, compensatory mitigation for marine bycatch (CMMB), is conceived as a way to replace or reduce mandated restrictions on fishing activities with compensatory activities (e.g., removal of introduced predators from islands) funded by levies placed on fishers. While efforts are underway to bring CMMB into policy discussions, to date there has not been a detailed evaluation of CMMB's potential as a conservation tool, and in particular, a list of necessary and sufficient criteria that CMMB must meet to be an effective conservation strategy. Here we present a list of criteria to assess CMMB that are tied to critical ecological aspects of the species targeted for conservation, the range of possible mitigation activities, and the multi-species impact of fisheries bycatch. We conclude that, overall, CMMB has little potential for benefit and a substantial potential for harm if implemented to solve most fisheries bycatch problems. In particular, CMMB is likely to be effective only when applied to short-lived and highly-fecund species (not the characteristics of most bycatch-impacted species) and to fisheries that take few non-target species, and especially few non-seabird species (not the characteristics of most fisheries). Thus, CMMB appears to have limited application and should only be implemented after rigorous appraisal on a case-specific basis; otherwise it has the potential to accelerate declines of marine species currently threatened by fisheries bycatch. ?? 2008 Finkelstein et al.

PLoS ONE

Prioritizing avian species for their risk of population-level consequences from wind energy development

Recent growth in the wind energy industry has increased concerns about its impacts on wildlife populations. Direct impacts of wind energy include bird and bat collisions with turbines whereas indirect impacts include changes in wildlife habitat and behavior. Although many species may withstand these effects, species that are long-lived with low rates of reproduction, have specialized habitat preferences, or are attracted to turbines may be more prone to declines in population abundance. We developed a prioritization system to identify the avian species most likely to experience population declines from wind facilities based on their current conservation status and their expected risk from turbines. We developed 3 metrics of turbine risk that incorporate data on collision fatalities at wind facilities, population size, life history, species’ distributions relative to turbine locations, number of suitable habitat types, and species’ conservation status. We calculated at least 1 measure of turbine risk for 428 avian species that breed in the United States. We then simulated 100,000 random sets of cutoff criteria (i.e., the metric values used to assign species to different priority categories) for each turbine risk metric and for conservation status. For each set of criteria, we assigned each species a priority score and calculated the average priority score across all sets of criteria. Our prioritization system highlights both species that could potentially experience population decline caused by wind energy and species at low risk of population decline. For instance, several birds of prey, such as the long-eared owl, ferruginous hawk, Swainson’s hawk, and golden eagle, were at relatively high risk of population decline across a wide variety of cutoff values, whereas many passerines were at relatively low risk of decline. This prioritization system is a first step that will help researchers, conservationists, managers, and industry target future study and management activity.

PLoS ONE

How much is enough? The recurrent problem of setting measurable objectives in conservation

International agreements, environmental laws, resource management agencies, and environmental nongovernmental organizations all establish objectives that define what they hope to accomplish. Unfortunately, quantitative objectives in conservation are typically set without consistency and scientific rigor. As a result, conservationists are failing to provide credible answers to the question “How much is enough?” This is a serious problem because objectives profoundly shape where and how limited conservation resources are spent, and help to create a shared vision for the future. In this article we develop guidelines to help steer conservation biologists and practitioners through the process of objective setting. We provide three case studies to highlight the practical challenges of objective setting in different social, political, and legal contexts. We also identify crucial gaps in our science, including limited knowledge of species distributions and of large-scale, long-term ecosystem dynamics, that must be filled if we hope to do better than setting conservation objectives through intuition and best guesses.

BioScience

Science for avian conservation: Priorities for the new millennium

Over the past decade, bird conservation activities have become the preeminent natural resource conservation effort in North America. Maturation of the North American Waterfowl Management Plan (NAWMP), establishment of Partners in Flight (PIF), and creation of comprehensive colonial waterbird and shorebird conservation plans have stimulated unprecedented interest in, and funding for, bird conservation in the United States, Canada, Mexico, and other countries in the western hemisphere. Key to that success in the United States has been active collaboration among federal, state and local governments, conservation organizations, academia, and industry. The U.S. Department of the Interior (DOI), which has primary statutory responsibility for migratory bird conservation and management, has been a key partner. Despite the great strides that have been made in bird conservation science, historical approaches to research and monitoring have often failed to provide sufficient information and understanding to effectively manage bird populations at large spatial scales. That shortcoming, and the lack of an integrated strategy and comprehensive set of research priorities, is more evident in light of the goals established by the North American Bird Conservation Initiative (NABCI). The NABCI is a trinational, coalition-driven effort to provide an organizational umbrella for existing conservation initiatives. The expanded focus of NABCI and individual bird conservation initiatives is to work together in an integrated, holistic fashion to keep common birds common and to increase populations of declining, threatened, and endangered species. To assist bird conservation initiatives in defining goals and developing new approaches to effective research, the U.S. Geological Survey (USGS), the research agency of DOI, convened a workshop, “Science for Avian Conservation: Understanding, Modeling, and Applying Ecological Relationships,” on 31 October–2 November 2000, which brought together 51 scientists from USGS, as well as scientists and conservationists from other agencies and organizations actively participating in NABCI. As the lead federal agency involved in bird conservation research, USGS has a clear legislative mandate to provide scientific information upon which future management plans and actions will be built. This article summarizes key issues and recommendations that arose from that workshop. The principal goal of the workshop was to guide USGS in defining its role, assessing capabilities, and directing future agency planning in support of bird conservation. A major component was to identify key areas of research needed in this new era of bird conservation science. Although tailored to the mission of USGS, workshop recommendations visualize a bold direction for future avian conservation science in which research and monitoring work in tandem with management to increase our understanding of avian populations and the processes that affect them. The USGS is a science agency whose role is to provide objective scientific information to management agencies and therefore is not directly involved in high-level resource policy-making or on-the-ground management decision making. Nevertheless, it is important to note that effective policy decision making must integrate the best available science with political and economic realities to achieve successful avian conservation—an important subject acknowledged in the workshop, but largely beyond its scope of discussion. Williams (2003) questions regarding how scientific information can be effectively communicated to decision makers and incorporated into natural resource policy. Without an aggressive vision and the willingness of researchers, managers, and policy makers to implement it, conservation of North American birds is likely to proceed without the full benefit of scientific investigation. These recommendations represent the principal conclusions drawn by workshop participants and do not necessarily reflect official USGS policy.

The Auk

[Book Review] Biology of marine birds

A text devoted to the biology and ecology of marine birds has not been published in the last 15 years. Although a number of more taxa-specific texts have been produced during that period, there has not been a single publication that attempted to review our knowledge of all the major seabird orders since the works of Nelson (1979), Croxall (1987), and Furness and Monaghan (1987). Following the publication of those works, a large and impressive body of literature has been produced. Given the rapid expansion of the field in the last two decades, the time was ripe for production of an extensive compendium on the biology, ecology, and conservation of the world's seabirds. E. A. Schreiber and J. Burger are editors of this CRC publication, Biology of Marine Birds . The book consists of 19 chapters that vary in length from 15 to 51 pages. There are also two extensive appendices: (1) a list of seabird species (restricted to the orders Sphenisciformes, Procellariiformes, Pelecaniformes, and Charadriiformes, the latter limited to Stercorariidae, Laridae, Rhynchopidae, and Alcidae) and their IUCN status, and (2) a very useful table of species-specific life-history traits. The 19 chapters were prepared by 26 authors, among them some of the most respected and published seabird scientists in the world. A brief preface introduces the book, its objective (to provide an examination and summary of the research on seabirds), its audience (researchers, conservationists, managers, and policy-makers), and the taxa covered. The editors coauthored the introductory chapter, Seabirds in the Marine Environment. The authors describe distinctive characteristics of seabird life-histories in comparison to other taxa, hypotheses for why those lifestyles evolved and the potential role of energy limitation in the evolution of seabird life-histories. Along with a discussion of other common seabird traits, such as a propensity for colonial breeding, the authors also suggest directions for future research in seabird ecology.

The Auk

Female-biased sex ratio, polygyny, and persistence in the endangered Southwestern Willow Flycatcher (Empidonax traillii extimus)

Demographic changes in populations, such as skewed sex ratios, are of concern to conservationists, especially in small populations in which stochastic and other events can produce declines leading to extirpation. We documented a decline in one of the few remaining populations of Southwestern Willow Flycatcher ( Empidonax traillii extimus ) in southern California, USA, which dropped from 40 to 5 adults between 2000 and 2015. Declines were unequal between sexes (94% for males, 82% for females). Adult sex ratios were female-biased in 10 of 16 yr. The proportion of paired males that were polygynous ranged from 0% to 100%, depending on the ratio of females to males in the adult population. Some males paired with up to 5 females simultaneously. We investigated the role of nestling sex ratio in the female-biased adult sex ratio by using genetic techniques to determine sex from blood samples collected from 162 nestlings in 72 nests from 2002 to 2009. Both population-level and within-brood nestling sex ratios were female-biased, and were not influenced by nest order (first or subsequent), parental mating type (monogamous or polygynous), or year. Disproportionately more females than males were recruited into the breeding population, mirroring nestling and fledgling sex ratios. It thus appears that a skewed nestling sex ratio has contributed to a female-biased adult population, which in turn has influenced mating behavior. We propose that the capacity for polygyny, which generally occurs at low levels in Southwestern Willow Flycatchers, has allowed this population to persist through a decline that might otherwise have resulted in extinction.

The Condor