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USGS2005

Individual-based modeling of ecological and evolutionary processes

Individual-based models (IBMs) allow the explicit inclusion of individual variation in greater detail than do classical differential-equation and difference-equation models. Inclusion of such variation is important for continued progress in ecological and evolutionary theory. We provide a conceptual basis for IBMs by describing five major types of individual variation in IBMs: spatial, ontogenetic, phenotypic, cognitive, and genetic. IBMs are now used in almost all subfields of ecology and evolutionary biology. We map those subfields and look more closely at selected key papers on fish recruitment, forest dynamics, sympatric speciation, metapopulation dynamics, maintenance of diversity, and species conservation. Theorists are currently divided on whether IBMs represent only a practical tool for extending classical theory to more complex situations, or whether individual-based theory represents a radically new research program. We feel that the tension between these two poles of thinking can be a source of creativity in ecology and evolutionary theory.

Annual Review of Ecology, Evolution, and Systemati↗

USGS2019

Relative contribution of climate and non-climate drivers in determining dynamic rates ofboreal birds at the edge of their range

The Adirondack Park in New York State contains a unique and limited distribution of boreal ecosystem types, providing habitat for a number of birds at the southern edge of their range. Species are projected to shift poleward in a warming climate, and the limited boreal forest of the Adirondacks is expected to undergo significant change in response to rising temperatures and changing precipitation patterns. Here we expand upon a previous analysis to examine changes in occupancy patterns for eight species of boreal birds over a decade (2007–2016), and we assess the relative contribution of climate and non-climate drivers in determining colonization and extinction rates. Our analysis identifies patterns of declining occupancy for six of eight species, including some declines which appear to have become more pronounced since a prior analysis. Although non-climate drivers such as wetland area, connectivity, and human footprint continue to influence colonization and extinction rates, we find that for most species, occupancy patterns are best described by climate drivers. We modeled both average and annual temperature and precipitation characteristics and find stronger support for species’ responses to average climate conditions, rather than interannual climate variability. In general, boreal birds appear most likely to colonize sites that have lower levels of precipitation and a high degree of connectivity, and they tend to persist in sites that are warmer in the breeding season and have low and less variable precipitation in the winter. It is likely that these responses reflect interactions between broader habitat conditions and temperature and precipitation variables. Indirect climate influences as mediated through altered species interactions may also be important in this context. Given climate change predictions for both temperature and precipitation, it is likely that habitat structural changes over the long term may alter these relationships in the future.

New York↗

USGS2011

Rocky Mountain snowpack physical and chemical data for selected sites, 2010

The Rocky Mountain Snowpack program established a network of snowpack-sampling sites in the Rocky Mountain region, from New Mexico to Montana, to monitor the chemical content of snow and to understand the effects of regional atmospheric deposition on freshwater systems. Scientists with the U.S. Geological Survey, in cooperation with the National Park Service; the U.S. Department of Agriculture Forest Service; the Colorado Department of Public Health and Environment; Teton County, Wyoming; and others, annually collected and analyzed snow-pack samples at 48 or more sites in the Rocky Mountain region during 1993-2010. Sixty-three snowpack-sampling sites were each sampled once in 2010, and those data are presented in this report. Data include acid-neutralization capacity, specific conductance, pH, hydrogen ion concentrations, dissolved concentrations of major constituents (calcium, magnesium, sodium, potassium, ammonium, chloride, sulfate, and nitrate), dissolved organic carbon concentrations, snow-water equivalent, snow depth, total mercury concentrations, and ionic charge balance. Quality-assurance data for field and laboratory blanks and field replicates for 2010 also are included.

Rocky Mountains↗

USGS2014

Space use and resource selection by foraging Indiana bats at the northern edge of their distribution

Despite 4 decades of conservation concern, managing endangered Indiana bat ( Myotis sodalis ) populations remains a difficult wildlife resource issue facing natural resource managers in the eastern United States. After small signs of population recovery, the recent emergence of white-nose syndrome has led to concerns of local and/or regional extirpation of the species. Where Indiana bats persist, retaining high-quality foraging areas will be critical to meet physiological needs and ensure successful recruitment and overwinter survival. However, insight into foraging behavior has been lacking in the Northeast of the USA. We radio-tracked 12 Indiana bats over 2 summers at Fort Drum, New York, to evaluate factors influencing Indiana bat resource selection during night-time foraging. We found that foraging space use decreased 2% for every 100 m increase in distance to water and 6% for every 100 m away from the forest edge. This suggests high use of riparian areas in close proximity to forest and is somewhat consistent with the species’ foraging ecology in the Midwest and upper South. Given the importance of providing access to high-quality foraging areas during the summer maternity season, Indiana bat conservation at the northern extent of the species’ range will be linked to retention of forested habitat in close proximity to riparian zones.

Endangered Species Research↗

USGS2010

Comparisons of watershed sulfur budgets in southeast Canada and northeast US: New approaches and implications

Most of eastern North America receives elevated levels of atmospheric deposition of sulfur (S) that result from anthropogenic SO 2 emissions from fossil fuel combustion. Atmospheric S deposition has acidified sensitive terrestrial and aquatic ecosystems in this region; however, deposition has been declining since the 1970s, resulting in some recovery in previously acidified aquatic ecosystems. Accurate watershed S mass balances help to evaluate the extent to which atmospheric S deposition is retained within ecosystems, and whether internal cycling sources and biogeochemical processes may be affecting the rate of recovery from decreasing S atmospheric loads. This study evaluated S mass balances for 15 sites with watersheds in southeastern Canada and northeastern US for the period 1985 to 2002. These 15 sites included nine in Canada (Turkey Lakes, ON; Harp Lake, ON; Plastic Lake, ON; Hermine, QC; Lake Laflamme, QC; Lake Clair, QC; Lake Tirasse, QC; Mersey, NS; Moosepit, NS) and six in the US (Arbutus Lake, NY; Biscuit Brook, NY; Sleepers River, VT; Hubbard Brook Experimental Forest, NH; Cone Pond, NH; Bear Brook Watershed, ME). Annual S wet deposition inputs were derived from measured bulk or wet-only deposition and stream export was obtained by combining drainage water fluxes with SO 4 2− concentrations. Dry deposition has the greatest uncertainty of any of the mass flux calculations necessary to develop accurate watershed balances, and here we developed a new method to calculate this quantity. We utilized historical information from both the US National Emissions Inventory and the US (CASTNET) and the Canadian (CAPMoN) dry deposition networks to develop a formulation that predicted SO 2 concentrations as a function of SO 2 emissions, latitude and longitude. The SO 2 concentrations were used to predict dry deposition using relationships between concentrations and deposition flux derived from the CASTNET or CAPMoN networks. For the year 2002, we compared the SO 2 concentrations and deposition predictions with the predictions of two continental-scale air quality models, the Community Multiscale Air Quality (CMAQ) model and A Unified Regional Air-quality Modeling System (AURAMS) that utilize complete inventories of emissions and chemical budgets. The results of this comparison indicated that the predictive relationship provides an accurate representation of SO 2 concentrations and S deposition for the region that is generally consistent with these models, and thus provides confidence that our approach could be used to develop accurate watershed S budgets for these 15 sites. Most watersheds showed large net losses of SO 4 2− on an annual basis, and the watershed mass balances were grouped into five categories based on the relative value of mean annual net losses or net gains. The net annual fluxes of SO 4 2− showed a strong relationship with hydrology; the largest net annual negative fluxes were associated with years of greatest precipitation amount and highest discharge. The important role of catchment hydrology on S budgets suggests implications for future predicted climate change as it affects patterns of precipitation and drought. The sensitivity of S budgets is likely to be greatest in watersheds with the greatest wetland area, which are particularly sensitive to drying and wetting cycles. A small number of the watersheds in this analysis were shown to have substantial S sources from mineral weathering, but most showed evidence of an internal source of SO 4 2− , which is likely from the mineralization of organic S stored from decades of increased S deposition. Mobilization of this internal S appears to contribute about 1–6 kg S ha −1 year −1 to stream fluxes at these sites and is affecting the rate and extent of recovery from acidification as S deposition rates have declined in recent years. This internal S source should be considered when developing critical deposition loads that will promote ecosystem recovery from acidification and the depletion of nutrient cations in the northeastern US and southeastern Canada.

Connecticut, Maine, New Hampshire, New Jersey, New↗

USGS2011

Hydrological mobilization of mercury and dissolved organic carbon in a snow-dominated, forested watershed: Conceptualization and modeling

The mobilization of mercury and dissolved organic carbon (DOC) during snowmelt often accounts for a major fraction of the annual loads. We studied the role of hydrological connectivity of riparian wetlands and upland/wetland transition zones to surface waters on the mobilization of Hg and DOC in Fishing Brook, a headwater of the Adirondack Mountains, New York. Stream water total mercury (THg) concentrations varied strongly (mean = 2.25 ± 0.5 ng L −1 ), and the two snowmelt seasons contributed 40% (2007) and 48% (2008) of the annual load. Methyl mercury (MeHg) concentrations ranged up to 0.26 ng L −1 , and showed an inverse log relationship with discharge. TOPMODEL‐simulated saturated area corresponded well with wetland areas, and the application of a flow algorithm based elevation‐above‐creek approach suggests that most wetlands become well connected during high flow. The dynamics of simulated saturated area and soil storage deficit were able to explain a large part of the variation of THg concentrations (r 2 = 0.53 to 0.72). In contrast, the simulations were not able to explain DOC variations and DOC and THg concentrations were not correlated. These results indicate that all three constituents, THg, MeHg, and DOC, follow different patterns at the outlet: (1) the mobilization of THg is primarily controlled by the saturation state of the catchment, (2) the dilution of MeHg suggests flushing from a supply limited pool, and (3) DOC dynamics follow a pattern different from THg dynamics, which likely results from differing gain and/or loss processes for THg and/or DOC within the Fishing Brook catchment.

New York↗

USGS2008

Nitrogen immobilization by wood-chip application: Protecting water quality in a northern hardwood forest

Forest harvesting disrupts the nitrogen cycle, which may affect stream water quality by increasing nitrate concentrations, reducing pH and acid neutralizing capacity, and mobilizing aluminum and base cations. We tested the application of wood chips derived from logging slash to increase immobilization of N after harvesting, which should reduce nitrate flux to streams. In August 2004, a stand of northern hardwoods was patch-clearcut in the Catskill Mountains, NY, and four replicates of three treatments were implemented in five 0.2-ha cut patches. Wood chips were applied to the soil surface at a rate equivalent to the amount of slash smaller than eight inches in diameter (1?? treatment). A second treatment doubled that rate (2??), and a third treatment received no chips (0??). Additionally, three uncut reference plots were established in nearby forested areas. Ion exchange resin bags and soil KCl-extractions were used to monitor nitrate availability in the upper 5-10 cm of soil approximately every seven weeks, except in winter. Resin bags indicated that the wood chips retained 30% or 42% of the nitrate pulse, while for KCl extracts, the retention rate was 78% or 100% of the difference between 0?? and uncut plots. During the fall following harvest, wood-chip treated plots had resin bag soil nitrate concentrations about 25% of those in 0?? plots (p = 0.0001). In the first growing season after the cut, nitrate concentrations in wood-chip treated plots for KCl extracts were 13% of those in 0?? treatments (p = 0.03) in May and about half those in 0?? treatments (p = 0.01) in July for resin bags. During spring snowmelt, however, nitrate concentrations were high and indistinguishable among treatments, including the uncut reference plots for resin bags and below detection limit for KCl extracts. Wood chips incubated in litterbags had an initial C:N of 125:1, which then decreased to 70:1 after one year of field incubation. These changes in C:N values indicate that the wood-chip application can potentially immobilize between 19 and 38 kg N ha-1 in the first year after harvesting, depending on the rate of wood-chip application. Our results suggest that the application of wood chips following harvesting operations can contribute to the protection of water quality and warrant additional research as a new Best Management Practice following cutting in regions that receive elevated levels of atmospheric N deposition. ?? 2008 Elsevier B.V. All rights reserved.

Forest Ecology and Management↗

USGS1993

Evaluation of three elevated mist-net systems for sampling birds

Three light-weight, low-canopy mist-net systems were developed and tested in dry tropical scrub, mangrove and forest habitats. One plastic (polyvinyl chloride) and two aluminum pole systems (with and without pulleys) were used to support mist nets to heights of up to 7.3 m. Although the aluminum telescoping-pole system (without pulleys) was expensive initially ( 79-141/unit (US)), its use reduced capture of nontarget species and may have increased capture of target species when compared with ground-level netting. In one year, its use also reduced labor costs by 756, which completely offset the higher cost of the aluminum telescoping-pole system when compared to the plastic-pole system ( 19/unit). Unlike the plastic-pole system, the aluminum telescoping-pole system was adjustable to any height within its range of 1.8 to 7.3 m, was 1.5 m higher, was more efficient to operate in the field, and was easily moved to new locations. For capture of psittacines, the pulleys of the aluminum telescoping-pole system were not necessary, but their use may assist in efficiently retrieving large numbers of birds from the nets. The aluminum telescoping-pole system was efficient in capturing psittacines, columbids, passerines and possibly chiropterans in habitats with canopies lt 10 m or in the forest subcanopy.

Journal of Field Ornithology↗

USGS2013

Controls on variations in MODIS fire radiative power in Alaskan boreal forests: implications for fire severity conditions

Fire activity in the Alaskan boreal forest, though episodic at annual and intra-annual time scales, has experienced an increase over the last several decades. Increases in burned area and fire severity are not only releasing more carbon to the atmosphere, but likely shifting vegetation composition in the region towards greater deciduous dominance and a reduction in coniferous stands. While some recent studies have addressed qualitative differences between large and small fire years in the Alaskan boreal forest, the ecological effects of a greater proportion of burning occurring during large fire years and during late season fires have not yet been examined. Some characteristics of wildfires that can be detected remotely are related to fire severity and can provide new information on spatial and temporal patterns of burning. This analysis focused on boreal wildfire intensity (fire radiative power, or FRP) contained in the Moderate Resolution Imaging Spectroradiometer (MODIS) daily active fire product from 2003 to 2010. We found that differences in FRP resulted from seasonality and intra-annual variability in fire activity levels, vegetation composition, latitudinal variation, and fire spread behavior. Our studies determined two general categories of active fire detections: new detections associated with the spread of the fire front and residual pixels in areas that had already experienced front burning. Residual pixels had a lower average FRP than front pixels, but represented a high percentage of all pixels during periods of high fire activity (large fire years, late season burning, and seasonal periods of high fire activity). As a result, the FRP from periods of high fire activity was less intense than those from periods of low fire activity. Differences related to latitude were greater than expected, with higher latitudes burning later in the season and at a higher intensity than lower latitudes. Differences in vegetation type indicate that coniferous vegetation is the most fire prone, but deciduous vegetation is not particularly fire resistant, as the proportion of active fire detections in deciduous stands is roughly the same as the fraction of deciduous vegetation in the region. Qualitative differences between periods of high and low fire activity are likely to reflect important differences in fire severity. Large fire years are likely to be more severe, characterized by more late season fires and a greater proportion of residual burning. Given the potential for severe fires to effect changes in vegetation cover, the shift toward a greater proportion of area burning during large fire years may influence vegetation patterns in the region over the medium to long term.

Alaska↗

USGS2020

A global biophysical typology of mangroves and its relevance for ecosystem structure and deforestation

Mangrove forests provide many ecosystem services but are among the world’s most threatened ecosystems. Mangroves vary substantially according to their geomorphic and sedimentary setting; while several conceptual frameworks describe these settings, their spatial distribution has not been quantified. Here, we present a new global mangrove biophysical typology and show that, based on their 2016 extent, 40.5% (54,972 km 2 ) of mangrove systems were deltaic, 27.5% (37,411 km 2 ) were estuarine and 21.0% (28,493 km 2 ) were open coast, with lagoonal mangroves the least abundant (11.0%, 14,993 km 2 ). Mangroves were also classified based on their sedimentary setting, with carbonate mangroves being less abundant than terrigenous, representing just 9.6% of global coverage. Our typology provides a basis for future research to incorporate geomorphic and sedimentary setting in analyses. We present two examples of such applications. Firstly, based on change in extent between 1996 and 2016, we show while all types exhibited considerable declines in area, losses of lagoonal mangroves (− 6.9%) were nearly twice that of other types. Secondly, we quantify differences in aboveground biomass between mangroves of different types, with it being significantly lower in lagoonal mangroves. Overall, our biophysical typology provides a baseline for assessing restoration potential and for quantifying mangrove ecosystem service provision.

Scientific Reports↗

USGS2024

Integrating presence-only and detection/non-detection data to estimate distributions and expected abundance of difficult-to-monitor species on a landscape-scale

Estimating species distribution and abundance is foundational to effective management and conservation. Using an integrated species distribution model that combines presence-only data from various sources with detection/non-detection data from structured surveys, we estimated the distribution and expected abundance of three difficult-to-monitor mammals of management concern across New York State, namely, coyotes ( Canis latrans ), bobcats ( Lynx rufus ) and black bears ( Ursus americanus ). Three distinct landscape-scale camera trap surveys provided detection/non-detection data over 9 years between 2013 and 2021, and we augmented those data with incidental records of our focal species from public repositories. We used an inhomogeneous Poisson point process to construct an integrated model that fit both data types simultaneously. We demonstrate a simple application of spatial point density of all species records in the accessed public databases to inform the thinning process to account for unknown spatial sampling in the presence-only data, often referred to as the ‘magic covariate’. Using this approach, we examine habitat associations and provide spatially explicit estimates in expected abundance across the entirety of New York State for all three focal species. As expected, coyotes were the most widely distributed and abundant species, with a strong positive association with agricultural land uses. Bobcats exhibited low expected abundance throughout the state and showed positive associations with deciduous forest and forest edge, and a negative association with road density. Finally, we observed considerable spatial variation in abundance of black bears with expected abundance increasing in association with various forest cover and composition covariates and decreasing with crop cover. We present insights into habitat associations and spatial variation in abundance, and provide management implications for each of the species of interest. Synthesis and applications . Our integrated modelling method allows for managers to use citizen sightings combined with detection/non-detection surveys to estimate robust indices of abundance for both high- and low-density, and wide-spread versus patchily distributed species. Through comparison with previous studies, we highlight how broad-scale programmes, such as the statewide efforts to estimate species distributions undertaken here, can benefit substantively from integrated models that leverage additional data (here, incidental records) from a larger region of space, and thus capture more landscape heterogeneity than is plausible within formalized surveys alone.

New York↗

USGS2013

Estimating the extent of impervious surfaces and turf grass across large regions

The ability of researchers to accurately assess the extent of impervious and pervious developed surfaces, e.g., turf grass, using land-cover data derived from Landsat satellite imagery in the Chesapeake Bay watershed is limited due to the resolution of the data and systematic discrepancies between developed land-cover classes, surface mines, forests, and farmlands. Estimates of impervious surface and turf grass area in the Mid-Atlantic, United States that were based on 2006 Landsat-derived land-cover data were substantially lower than estimates based on more authoritative and independent sources. New estimates of impervious surfaces and turf grass area derived using land-cover data combined with ancillary information on roads, housing units, surface mines, and sampled estimates of road width and residential impervious area were up to 57 and 45% higher than estimates based strictly on land-cover data. These new estimates closely approximate estimates derived from authoritative and independent sources in developed counties.

Delaware;Maryl;New York;Pennsylvania↗

USGS2018

Southeast

The Southeast includes vast expanses of coastal and inland low-lying areas, the southern portion of the Appalachian Mountains, numerous high-growth metropolitan areas, and large rural expanses. These beaches and bayous, fields and forests, and cities and small towns are all at risk from a changing climate. While some climate change impacts, such as sea level rise and extreme downpours, are being acutely felt now, others, like increasing exposure to dangerous high temperatures, humidity, and new local diseases, are expected to become more significant in the coming decades. While all regional residents and communities are potentially at risk for some impacts, some communities or populations are at greater risk due to their locations, services available to them, and economic situations. Observed warming since the mid-20th century has been uneven in the Southeast region, with average daily minimum temperatures increasing three times faster than average daily maximum temperatures. The number of extreme rainfall events is increasing. Climate model simulations of future conditions project increases in both temperature and extreme precipitation. Trends towards a more urbanized and denser Southeast are expected to continue, creating new climate vulnerabilities. Cities across the Southeast are experiencing more and longer summer heat waves. Vector-borne diseases pose a greater risk in cities than in rural areas because of higher population densities and other human factors, and the major urban centers in the Southeast are already impacted by poor air quality during warmer months. Increasing precipitation and extreme weather events will likely impact roads, freight rail, and passenger rail, which will likely have cascading effects across the region. Infrastructure related to drinking water and wastewater treatment also has the potential to be compromised by climate-related events. Increases in extreme rainfall events and high tide coastal floods due to future climate change will impact the quality of life of permanent residents as well as tourists visiting the low-lying and coastal regions of the Southeast. Sea level rise is contributing to increased coastal flooding in the Southeast, and high tide flooding already poses daily risks to businesses, neighborhoods, infrastructure, transportation, and ecosystems in the region. There have been numerous instances of intense rainfall events that have had devastating impacts on inland communities in recent years. The ecological resources that people depend on for livelihoods, protection, and well-being are increasingly at risk from the impacts of climate change. Sea level rise will result in the rapid conversion of coastal, terrestrial, and freshwater ecosystems to tidal saline habitats. Reductions in the frequency and intensity of cold winter temperature extremes are already allowing tropical and subtropical species to move northward and replace more temperate species. Warmer winter temperatures are also expected to facilitate the northward movement of problematic invasive species, which could transform natural systems north of their current distribution. In the future, rising temperatures and increases in the duration and intensity of drought are expected to increase wildfire occurrence and also reduce the effectiveness of prescribed fire practices. Many in rural communities are maintaining connections to traditional livelihoods and relying on natural resources that are inherently vulnerable to climate changes. Climate trends and possible climate futures show patterns that are already impacting—and are projected to further impact—rural sectors, from agriculture and forestry to human health and labor productivity. Future temperature increases are projected to pose challenges to human health. Increases in temperatures, water stress , freeze-free days, drought, and wildfire risks, together with changing conditions for invasive species and the movement of diseases, create a number of potential risks for existing agricultural systems. Rural communities tend to be more vulnerable to these changes due to factors such as demography, occupations, earnings, literacy, and poverty incidence. In fact, a recent economic study using a higher scenario (RCP8.5) suggests that the southern and midwestern populations are likely to suffer the largest losses from future climate changes in the United States. Climate change tends to compound existing vulnerabilities and exacerbate existing inequities. Already poor regions, including those found in the Southeast, are expected to continue incurring greater losses than elsewhere in the United States.

Report↗

USGS2007

Relation of macroinvertebrate community impairment to catchment characteristics in New Jersey streams

ABSTRACT: The level of macroinvertebrate community impairment was statistically related to selected basin and water-quality characteristics in New Jersey streams. More than 700 ambient biomonitoring stations were chosen to evaluate potential and known anthropogenic effects. Macroinvertebrate communities were assessed with a modified rapid-bioassessment approach using three impairment ratings (nonimpaired, moderately impaired, and severely impaired). Maximum-likelihood multiple logistic-regression analysis was used to develop equations defining the probability of community impairment above predetermined impairment levels. Seven of the original 140 explanatory variables were highly related to the level of community impairment. Explanatory variables found to be most useful for predicting severe macroinvertebrate community impairment were the amount of urban land and total flow of municipal effluent. Area underlain by the Reading Prong physiographic region and amount of forested land were inversely related to severe impairment. Nonparametric analysis of variance on rank-transformed bioassessment scores was used to evaluate differences in level of impairment among physiographic regions and major drainage areas simultaneously. Rejection of the null hypothesis indicated that the levels of impairment among all six physiographic regions and five major drainage areas were not equal. Physiographic regions located in the less urbanized northwest portion of New Jersey were not significantly different from each other and had the lowest occurrence of severely impaired macroinvertebrate communities. Physiographic regions containing urban centers had a higher probability of exhibiting a severely impaired macroinvertebrate community. Analysis of major drainage areas indicates that levels of impairment in the Atlantic Coastal Rivers drainage area differed significantly from those in the Lower Delaware River drainage area.

Journal of the American Water Resources Associatio↗

USGS2023

Estimating fat content in barred owls (Strix varia) with predictive models developed from direct measures of proximate body composition

Body condition indices and related metrics can help assess habitat quality and other ecological processes, and ideally, these metrics are based on measures of lipids directly extracted from the species of interest. In recent decades, barred owls ( Strix varia ) have become a species of conservation concern as they invaded older forests of the US Pacific Northwest, and caused population declines of the closely related and federally threatened northern spotted owl ( Strix occidentalis caurina ). A simple and effective measure of barred owl body condition could help to understand how habitat quality varies within their new range, which in turn can inform their management and other aspects of their ecology. Using 77 barred owl carcasses collected during experimental removals in Washington and Oregon, USA, we measured the amount of lipid in each specimen with proximate body composition analysis. We then fit and compared (with adjusted R 2 values) alternative linear regression models to estimate the percent lipids in dry mass of the owls based on morphometric body condition indices, a qualitative fat score of subcutaneous breast fat, sex and the time of year females were collected (relative to egg production). Adjusted R 2 values for all models ranged from 0.49 to 0.87, with the best model including mass divided by foot-pad length, fat score, sex and the time of year a female was collected. Most models generated comparable estimates of percent lipids at a population level and we provided correction factors to apply these models when used with live barred owls, allowing for site-specific comparisons of body condition among individuals inhabiting a diversity of environmental conditions.

Conservation Physiology↗

USGS2023

Gene expression reveals immune response strategies of naïve Hawaiian honeycreepers experimentally infected with introduced avian malaria

The unprecedented rise in the number of new and emerging infectious diseases in the last quarter century poses direct threats to human and wildlife health. The introduction to the Hawaiian archipelago of Plasmodium relictum and the mosquito vector that transmits the parasite has led to dramatic losses in endemic Hawaiian forest bird species. Understanding how mechanisms of disease immunity to avian malaria may evolve is critical as climate change facilitates increased disease transmission to high elevation habitats where malaria transmission has historically been low and the majority of the remaining extant Hawaiian forest bird species now reside. Here, we compare the transcriptomic profiles of highly susceptible Hawai‘i ‘amakihi ( Chlorodrepanis virens ) experimentally infected with P. relictum to those of uninfected control birds from a naïve high elevation population. We examined changes in gene expression profiles at different stages of infection to provide an in-depth characterization of the molecular pathways contributing to survival or mortality in these birds. We show that the timing and magnitude of the innate and adaptive immune response differed substantially between individuals that survived and those that succumbed to infection, and likely contributed to the observed variation in survival. These results lay the foundation for developing gene-based conservation strategies for Hawaiian honeycreepers by identifying candidate genes and cellular pathways involved in the pathogen response that correlate with a bird’s ability to recover from malaria infection.

Hawaii↗

USGS2024

Climate, food and humans predict communities of mammals in the United States

Aim The assembly of species into communities and ecoregions is the result of interacting factors that affect plant and animal distribution and abundance at biogeographic scales. Here, we empirically derive ecoregions for mammals to test whether human disturbance has become more important than climate and habitat resources in structuring communities. Location Conterminous United States. Time Period 2010–2021. Major Taxa Studied Twenty-five species of mammals. Methods We analysed data from 25 mammal species recorded by camera traps at 6645 locations across the conterminous United States in a joint modelling framework to estimate relative abundance of each species. We then used a clustering analysis to describe 8 broad and 16 narrow mammal communities. Results Climate was the most important predictor of mammal abundance overall, while human population density and agriculture were less important, with mixed effects across species. Seed production by forests also predicted mammal abundance, especially hard-mast tree species. The mammal community maps are similar to those of plants, with an east–west split driven by different dominant species of deer and squirrels. Communities vary along gradients of temperature in the east and precipitation in the west. Most fine-scale mammal community boundaries aligned with established plant ecoregions and were distinguished by the presence of regional specialists or shifts in relative abundance of widespread species. Maps of potential ecosystem services provided by these communities suggest high herbivory in the Rocky Mountains and eastern forests, high invertebrate predation in the subtropical south and greater predation pressure on large vertebrates in the west. Main Conclusions Our results highlight the importance of climate to modern mammals and suggest that climate change will have strong impacts on these communities. Our new empirical approach to recognizing ecoregions has potential to be applied to expanded communities of mammals or other taxa.

Conterminous United States↗

USGS2013

Diet of the eastern mudminnow (Umbra pygmaea DeKay) from two geographically distinct populations within the North American native range

Umbra pygmaea (Eastern Mudminnow) is a freshwater species common in Atlantic slope coastal lowlands from southern New York to northern Florida and is typical of slow-moving, mud-bottomed, and highly vegetated streams, swamps, and small ponds. We examined its seasonal food habits at the Great Swamp National Wildlife Refuge (NWR), NJ and at the Croatan National Forest, NC. A total of 147 Eastern Mudminnow from 35–112 mm TL and 190 Eastern Mudminnow from 22–89 mm TL were examined from these sites, respectively. At both locations, we found it to be a bottom-feeding generalist that consumes cladocerans, ostracods, chironomid larvae, coleopteran larvae, and other insects and crustaceans. Ostracods were most common in the diet at the Great Swamp NWR and occurred in 62% ± 2.5% of the stomachs with food. At Croatan National Forest, chironomid larvae were most common and occurred in 66.7% ± 15.8% of the stomachs. There were no statistically significant differences in diet composition between the sites during the winter, summer, and fall. However, when compared on an annual basis, Jaccard’s Index (θ J = 0.636, P = 0.05) suggested that the diet at the two study sites was significantly different. While we identified the same major food groups at both locations, the utilization of these food groups varied seasonally. Detritus was a major stomach content at both locations throughout the year. We also documented cannibalism during the summer season at both locations. The seasonal diet of the Eastern Mudminnow was similar to that of Umbra limi (Central Mudminnow) and Umbra krameri (European Mudminnow). Our findings here are the first quantitative examinations of seasonal differences in the diet of the Eastern Mudminnow within its native North American range.

Northeastern Naturalist↗