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Publications (248)
Infanticide and adoption have been attributed to sexual selection, where an individual later reproduces with the parent whose offspring it killed or adopted. While sexually selected infanticide is well known, evidence for sexually selected adoption is anecdotal. We report on both behaviors at 346 nests over 27 y in green-rumped parrotlets ( Forpus...
Correlative species distribution models are widely used to quantify past shifts in ranges or communities, and to predict future outcomes under ongoing global change. Practitioners confront a wide range of potentially plausible models for ecological dynamics, but most specific applications only consider a narrow set. Here, we clarify that certain mo...
The black rail, Laterallus jamaicensis, is one of the most secretive and poorly understood birds in the Americas. Two of its five subspecies breed in North America: the Eastern black rail (L. j. jamaicensis), found primarily in the southern and mid-Atlantic states, and the California black rail (L. j. coturniculus), inhabiting California and Arizon...
The Virginia rail, Rallus limicola, is a member of the family Rallidae, which also includes many other species of secretive and poorly studied wetland birds. It is recognized as a single species throughout its broad distribution in North America where it is exploited as a game bird, often with generous harvest limits, despite a lack of systematic p...
Climate and land-use change could exhibit concordant effects that favor or disfavor the same species, which would amplify their impacts, or species may respond to each threat in a divergent manner, causing opposing effects that moderate their impacts in isolation. We used early 20th century surveys of birds conducted by Joseph Grinnell paired with...
Converging lines of inquiry from across the social and biological sciences target the adult sex ratio (ASR; the proportion of males in the adult population) as a fundamental population-level determinant of behavior. The ASR, which indicates the relative number of potential mates to competitors in a population, frames the selective arena for competi...
Phenotypic convergence across distantly related taxa can be driven by similar selective pressures from the environment or intrinsic constraints. The roles of these processes on physiological strategies, such as homeothermy, are poorly understood. We studied the evolution of thermal properties of mammalian pelage in a diverse community of rodents in...
Two controversial tenets of metapopulation biology are whether patch quality and the surrounding matrix are more important to turnover (colonisation and extinction) than biogeography (patch area and isolation) and whether factors governing turnover during equilibrium also dominate nonequilibrium dynamics. We tested both tenets using 18 years of sur...
Prelinguistic babbling is a critical phase in infant language development and is best understood in temperate songbirds where it occurs primarily in males at reproductive maturity and is modulated by sex steroids. Parrots of both sexes are icons of tropical vocal plasticity, but vocal babbling is unreported in this group and whether the endocrine s...
Small mammals in hot deserts often avoid heat via nocturnality and fossoriality and are thought to have a limited capacity to dissipate heat using evaporative cooling. Research to date has focused on thermoregulatory responses to air temperatures (Ta) below body temperature (Tb). Consequently, the thermoregulatory performance of small mammals expos...
We examine the evidence linking species’ traits to contemporary range shifts and find they are poor predictors of range shifts that have occurred over decades to a century. We then discuss reasons for the poor performance of traits for describing interspecific variation in range shifts from two perspectives: ( a) factors associated with species’ tr...
Theory posits that resilience of ecosystems increases when there is a diversity of agents (e.g., species) and linkages between them. If ecosystems are conceptualized as components of coupled human and natural systems, then a corollary would be that novel types of human-induced diversity may also foster resilience. We explored this hypothesis by stu...
Microhabitat matters
Understanding how our warming climate affects vulnerable species is of paramount importance. However, predicting responses is complicated because species are complex and may adapt or respond in distinct ways. Riddell et al. compared a century-old dataset on species richness in the Mojave against modern surveys to measure climat...
Transition zones between biomes, also known as ecotones, are areas of pronounced ecological change. They are primarily maintained by abiotic factors and disturbance regimes that could hinder or promote species range shifts in response to climate change. We evaluated how climate change has affected metacommunity dynamics in two adjacent biomes and a...
The rescue effect in metapopulations hypothesises that less isolated patches are unlikely to go extinct because recolonisation may occur between breeding seasons (‘recolonisation rescue’), or immigrants may sufficiently bolster population size to prevent extinction altogether (‘demographic rescue’). These mechanisms have rarely been demonstrated di...
The field metabolic rate (FMR) of an endothermic animal represents its energy expenditure in a natural environment, or its energy budget, and its field water flux (FWF) reflects the animal's water requirements.
We examined FMR of 103 species and FWF of 75 species of adult birds from direct field measurements using the doubly labelled water method,...
The snow leopard (Panthera uncia) is an apex predator on the Tibetan Plateau and in the surrounding mountain ranges. It is listed as Vulnerable in the IUCN's Red List. The large home range and low population densities of this species mandate range-wide conservation prioritization. Two efforts for range-wide snow leopard conservation planning have b...
Endotherms dissipate heat to the environment to maintain a stable body temperature at high ambient temperatures, which requires them to maintain a balance between heat dissipation and water conservation. Birds are relatively small, contain a large amount of metabolically expensive tissue, and are mostly diurnal, making them susceptible to physiolog...
Climate change threatens global biodiversity by increasing extinction risk, yet few studies have uncovered a physiological basis of climate-driven species declines. Maintaining a stable body temperature is a fundamental requirement for homeothermic animals, and water is a vital resource that facilitates thermoregulation through evaporative cooling,...
Life history theory predicts that physiological and behavioral responsiveness to stress should be delayed in development until the benefits of heightened reactivity outweigh the costs of potentially chronic glucocorticoid levels. Birds often acquire stress-responsiveness at locomotor independence, however, both stress-responsiveness and locomotor a...
Biological responses to climate change have been widely documented across taxa and regions, but it remains unclear whether species are maintaining a good match between phenotype and environment, i.e. whether observed trait changes are adaptive. Here we reviewed 10,090 abstracts and extracted data from 71 studies reported in 58 relevant publications...
Water often limits the distribution and productivity of wildlife in arid environments. Consequently, resource managers have constructed artificial water catchments (AWCs) in deserts of the southwestern United States, assuming that additional free water benefits wildlife. We tested this assumption by using data from acoustic and camera trap surveys...
Understanding how metapopulations persist in dynamic working landscapes requires assessing the behaviors of key actors that change patches as well as intrinsic factors driving turnover. Coupled human and natural systems (CHANS) research uses a multidisciplinary approach to identify the key actors, processes, and feedbacks that drive metapopulation...
We used data collected by automated recorders to generate baseline estimates of occupancy for >80 songbird species in the Great Valley. Site-level detection probabilities were high for the majority of songbirds, providing support for the effectiveness of automated recorders as a monitoring tool. Further, our research highlights potential starting p...
Significance
Deserts, already defined by climatic extremes, have warmed and dried more than other regions in the contiguous United States due to climate change. Our resurveys of sites originally visited in the early 20th century found Mojave Desert birds strongly declined in occupancy and sites lost nearly half of their species. Declines were assoc...
1. The rich biological diversity of the Mojave Desert Ecoregion is increasingly threatened by a changing climate and mounting land use pressures. An understanding of species distributions and their habitats is needed to guide management efforts that minimize the adverse impacts of these threats. We helped address this knowledge gap by determining b...
Dispersal distances are commonly inferred from occupancy data but have rarely been validated. Estimating dispersal from occupancy data is further complicated by imperfect detection and the presence of unsurveyed patches.
We compared dispersal distances inferred from seven years of occupancy data for 212 wetlands in a metapopulation of the secretive...
Executive Summary
1. In response to the drought State of Emergency declared in 2014, California's Department of Fish and Wildlife (CDFW) prioritized monitoring of wildlife populations and their associations with drought stressors and habitat features. As part of this effort, CDFW initiated Terrestrial Species Stressor Monitoring (TSM) surveys in 2...
Climate change refugia, areas buffered from climate change relative to their surroundings, are of increasing interest as natural resource managers seek to prioritize climate adaptation actions. However, evidence that refugia buffer the effects of anthropogenic climate change is largely missing. Focusing on the climate-sensitive Belding’s ground squ...
Significance
Climate warming poses two major challenges for birds: exposure to higher temperatures and disruption of the synchrony between nesting and resource emergence. To cope, birds are expected to track temperature by moving to cooler areas and to track resource emergence by breeding earlier. We show that these two responses are intertwined. E...
Jennions et al. introduce the different kinds of sex ratio and their biology.
Adult sex ratio (ASR, the proportion of males in the adult population) is a central concept in population and evolutionary biology, and is also emerging as a major factor influencing mate choice, pair bonding and parental cooperation in both human and non-human societies. However, estimating ASR is fraught with difficulties stemming from the effect...
Climate refugia management has been proposed as a climate adaptation strategy in the face of global change. Key to this strategy is identification of these areas as well as an understanding of how they are connected on the landscape. Focusing on meadows of the Sierra Nevada in California, we examined multiple factors affecting connectivity using ci...
There is an error in reference 3. The correct reference is: Stein BA, Glick P, Edelson N, Staudt A, editors. Climate-Smart Conservation: Putting Adaptation Principles into Practice. National Wildlife Federation. Washington, D.C.2014.
On 25 August 1916, the National Park Service Organic Act was signed into law by President Woodrow Wilson, thereby establishing the agency and its mission in a mere 731 words. The key mission, still in force today, is “to conserve the scenery and the natural and historic objects and the wild life therein and to provide for the enjoyment of the same...
Declines in raptor populations often result from the transformation of natural habitats to anthropogenic land uses, but the rate of population change can vary greatly among species. Declines associated with land transformation have been linked to loss of foraging habitat, prey resources and nest sites due to expanding cultivation, overgrazing and d...
Around the world, recovery planning for threatened species is being applied in an attempt to stem the current extinction crisis. Genetic factors linked to small population processes (eg inbreeding, loss of genetic diversity) play a key role in species viability. We examined how often genetic factors are considered in threatened species recovery pla...
Adult individuals that do not breed in a given year occur in a wide range of natural populations. However, such nonbreeders are often ignored in theoretical and empirical population studies, limiting our knowledge of how nonbreeders affect realized and estimated population dynamics and potentially impeding projection of deterministic and stochastic...
The stochastic and infrequent nature of long-distance dispersal often makes it difficult to detect. We quantified the frequency, distance, and timing of long-distance dispersal in a non-migratory, secretive wetland bird, the California black rail (Laterallus jamaicensis coturniculus), between an inland and a coastal metapopulation separated by grea...
Refugia have long been studied from paleontological and biogeographical perspectives to understand how populations persisted during past periods of unfavorable climate. Recently, researchers have applied the idea to contemporary landscapes to identify climate change refugia, here defined as areas relatively buffered from contemporary climate change...
Poyang Lake, the largest freshwater wetland in China, provides critical habitat for wintering waterbirds from the East Asian Flyway; however, landscape drivers of non-uniform bird diversity and abundance are not yet well understood. Using a winter 2006 waterbird survey, we examined the relationships among metrics of bird community diversity and abu...
Inference and estimates of abundance are critical for quantifying population dynamics and impacts of environmental change. Yet imperfect detection and other phenomena that cause zero inflation can induce estimation error and obscure ecological patterns.
Recent statistical advances provide an increasingly diverse array of analytical approaches for e...
Resurveys of historical collecting localities have revealed range shifts, primarily leading edge expansions, which have been attributed to global warming. However, there have been few spatially replicated community-scale resurveys testing whether species' responses are spatially consistent. Here we repeated early twentieth century surveys of small...
We examined how ecological and evolutionary (eco-evo) processes in population dynamics could be better integrated into population viability analysis (PVA). Complementary advances in computation and population genomics can be combined into an eco-evo PVA to offer powerful new approaches to understand the influence of evolutionary processes on popula...
Landscape genetics integrates theory and analytical methods of population genetics and landscape ecology. Research in this area has increased in recent decades, creating a plethora of options for study design and analysis. Here we present a practical toolbox for the design and analysis of landscape genetics studies following a seven-step framework:...
The Devils Hole pupfish is restricted to one wild population in a single aquifer-fed thermal pool in the Desert National Wildlife Refuge Complex. Since 1995 the pupfish has been in a nearly steady decline, where it was perched on the brink of extinction at 35-68 fish in 2013. A major strategy for conserving the pupfish has been the establishment of...
Background/Question/Methods
Many populations, particularly of birds, have large numbers of individuals that fail to obtain breeding opportunities in a given year. These nonbreeders often go undetected in population studies, which tend to be focused on the breeding population only. Consequently, little is known about how nonbreeders might influenc...
Background/Question/Methods
Accurate dispersal estimates are crucial for understanding metapopulation connectivity and projecting the response of organisms to habitat changes driven by development and climate change. However, direct dispersal estimates are often difficult and costly to obtain, particularly for rare or secretive species. In metapo...
Background/Question/Methods
Interest in the idea of climate change refugia has increased as natural resource managers seek targeted climate adaptation solutions. We used genetic and survey data to conduct a rare test of whether particular habitats are acting as refugia, buffering populations from recent climate change. We also examined whether hy...
Background/Question/Methods
Forecasts of global change on biodiversity project recent range relationships with climate variables to the future, often with alarming conclusions. Yet, 20th century environmental change has been pervasive, and few studies have documented local extinctions and population declines associated with recent climate change....
Background/Question/Methods
Montane environments represent areas where climate change should impact species' ranges over short distances due to elevational gradients. However, topographically complex landscapes may produce refugia from climate change if habitat patches are sufficiently connected to promote metapopulation persistence. Focusing on...
Understanding recent biogeographic responses to climate change is fundamental for improving our predictions of likely future responses and guiding conservation planning at both local and global scales. Studies of observed biogeographic responses to 20th century climate change have principally examined effects related to ubiquitous increases in temp...
Estimates of species richness and diversity are central to community and macroecology and are frequently used in conservation planning. Commonly used diversity metrics account for undetected species primarily by
controlling for sampling effort. Yet the probability of detecting an individual can vary among species, observers, survey methods, and sit...
Global climate is now warming rapidly and much larger changes are projected. The Arctic is home to a uniquely adapted flora and fauna, the fate of which remain uncertain as the climate continues to warm. Average temperatures in the Arctic have oscillated widely during each glacial cycle but notably, they have increased since the Last Glacial Maximu...
Estimates of species richness and diversity are central to community and macroecology and are frequently used in conservation planning. Commonly used diversity metrics account for undetected species primarily by controlling for sampling effort. Yet the probability of detecting an individual can vary among species, observers, survey methods, and sit...
Studies of evolution in wild populations often find that the heritable phenotypic traits of individuals producing the most offspring do not increase proportionally in the population. This paradox may arise when phenotypic traits influence both fecundity and viability and when there is a tradeoff between these fitness components, leading to opposing...
Although there are numerous examples of individual species moving up in elevation and poleward in latitude in response to 20th century climate change, how communities have responded is less well understood and requires fully accounting for changes in species-specific detectability over time, which has been neglected in past studies. We use a hierar...
Fundamental ecological research is both intrinsically interesting and provides the basic knowledge required to answer applied questions of importance to the management of the natural world. The 100th anniversary of the British Ecological Society in 2013 is an opportune moment to reflect on the current status of ecology as a science and look forward...
Recent historic abundance is an elusive parameter of great importance for conserving endangered species and understanding the pre-anthropogenic state of the biosphere. The number of studies that have used population genetic theory to estimate recent historic abundance from contemporary levels of genetic diversity has grown rapidly over the last two...
Projected effects of climate change on animal distributions primarily focus on consequences of temperature and largely ignore impacts of altered precipitation. While much evidence supports temperature‐driven range shifts, there is substantial heterogeneity in species' responses that remains poorly understood. We resampled breeding ranges of birds a...
Parrots rely heavily on vocal signals to maintain their social and mobile lifestyles. We studied vocal ontogeny in nests of wild green-rumped parrotlets (Forpus passerinus) in Venezuela. We identified three successive phases of vocal signaling that corresponded closely to three independently derived phases of physiological development. For each ont...
We examined how interactions between an individual's phenotype and its environment affect natal dispersal at multiple scales and the effects on lifetime reproductive success using a 22-year study of green-rumped parrotlets (Forpus passerinus). Dispersal increased or decreased lifetime reproductive success depending upon an individual's natal enviro...