Comprehensive wheat coccinellid detection dataset: Essential resource for digital entomology.

Wheat (Triticum aestivum) is a major cereal crop planted in the Southern Great Plains. This crop faces diverse pests that can affect their development and reduce yield productivity. For example, aphids are a significant pest in wheat, and their management relies on pesticides, which affect the sustainability and biodiversity of natural predators that prey on aphids. Coccinellids, commonly named lady beetles, are the most abundant natural predators of wheat. These natural enemies contribute to the natural predation of aphids, which can reduce the use of excessive pesticides for aphid management. Usually, visual observations of these natural enemies are performed during pest sampling; however, it is time-consuming and requires manual labor, which can be expensive. An automation system or detection models based on machine learning approaches that can detect these insects is needed to reduce unnecessary pesticide applications and manual labor costs. However, developing an automation system or computer vision models that automatically detect these natural enemies requires imagery to train and validate this cutting-edge technology. To solve this research problem, we collected this dataset, which includes images and label annotations to help researchers and students develop this technology that can benefit wheat growers and science to understand the capabilities of automation in Entomology. We collected a dataset using mobile devices, which included a diverse range of coccinellids on wheat images. The dataset consists of 2,133 images with a standard size of 640 × 640 pixels, which can be used to train and develop detection models for machine learning purposes. In addition, the dataset includes annotated labels that can be used for training models within the YOLO family or others, which have been proven to detect small insects in crops. Our dataset will increase the understanding of machine learning capabilities in entomology, precision agriculture, education, and crop pest management decisions.

Developing a brief assessment of social risks for the Veterans Health Administration Survey of Healthcare Experiences of Patients.

OBJECTIVE: To determine whether a 6- or 12-month look-back period affected rates of reported social risks in a social risk survey for use in the Veterans Health Administration and to assess associations of social risks with overall health and mental health. STUDY DESIGN: Cross-sectional survey of respondents randomized to 6- or 12-month look-back period. DATA SOURCES AND STUDY SETTING: Online survey with a convenience sample of Veterans in June and July 2021. DATA COLLECTION/EXTRACTION METHODS: Veteran volunteers were recruited by email to complete a survey assessing social risks, including financial strain, adult caregiving, childcare, food insecurity, housing, transportation, internet access, loneliness/isolation, stress, discrimination, and legal issues. Outcomes included self-reported overall health and mental health. Chi-squared tests compared the prevalence of reported social risks between 6- and 12-month look-back periods. Spearman correlations assessed associations among social risks. Bivariate and multivariable logistic regression models estimated associations between social risks and fair/poor overall and mental health. PRINCIPAL FINDINGS: Of 3418 Veterans contacted, 1063 (31.10%) responded (87.11% male; 85.61% non-Hispanic White; median age = 70, interquartile range [IQR] = 61-74). Prevalence of most reported social risks did not significantly differ by look-back period. Most social risks were weakly intercorrelated (median |r| = 0.24, IQR = 0.16-0.31). Except for legal issues, all social risks were associated with higher odds of fair/poor overall health and mental health in bivariate models. In models containing all significant social risks from bivariate models, adult caregiving and stress remained significant predictors of overall health; food insecurity, housing, loneliness/isolation, and stress remained significant for mental health. CONCLUSIONS: Six- and 12-month look-back periods yielded similar rates of reported social risks. Although most individual social risks are associated with fair/poor overall and mental health, when examined together, only adult caregiving, stress, loneliness/isolation, food, and housing remain significant.

Primary care experiences of veterans with opioid use disorder in the Veterans Health Administration.

BACKGROUND: While patients with substance use disorders (SUDs) are thought to encounter poor primary care experiences, the perspectives of patients with opioid use disorder (OUD), specifically, are unknown. This study compares the primary care experiences of patients with OUD, other SUDs and no SUD in the Veterans Health Administration. METHODS: The sample included Veterans who responded to the national Patient-Centered Medical Home Survey of Healthcare Experiences of Patients, 2013-2015. Respondents included 3554 patients with OUD, 36,175 with other SUDs, and 756,386 with no SUD; 742 OUD-diagnosed patients received buprenorphine. Multivariable multinomial logistic regressions estimated differences in the probability of reporting positive and negative experiences (0-100 scale) for patients with OUD, compared to patients with other SUDs and no SUD, and for OUD-diagnosed patients treated versus not treated with buprenorphine. RESULTS: Of all domains, patients with OUD reported the least positive experiences with access (31%) and medication decision-making (35%), and the most negative experiences with self-management support (35%) and provider communication (23%). Compared to the other groups, patients diagnosed with OUD reported fewer positive and/or more negative experiences with access, communication, office staff, provider ratings, comprehensiveness, care coordination, and self-management support (adjusted risk differences[aRDs] range from |2.9| to |7.0|). Among OUD-diagnosed patients, buprenorphine was associated with more positive experiences with comprehensiveness (aRD = 8.3) and self-management support (aRD = 7.1), and less negative experiences with care coordination (aRD = -4.9) and medication shared decision-making (aRD = -5.4). CONCLUSIONS: In a national sample, patients diagnosed with OUD encounter less positive and more negative experiences than other primary care patients, including those with other SUDs. Buprenorphine treatment relates positively to experiences with care comprehensiveness, medication decisions, and care coordination. As stakeholders encourage more primary care providers to manage OUD, it will be important for healthcare systems to attend to patient access and experiences with care in these settings.

Providing Positive Primary Care Experiences for Homeless Veterans Through Tailored Medical Homes: The Veterans Health Administration's Homeless Patient Aligned Care Teams.

BACKGROUND: In 2012, select Veterans Health Administration (VHA) facilities implemented a homeless-tailored medical home model, called Homeless Patient Aligned Care Teams (H-PACT), to improve care processes and outcomes for homeless Veterans. OBJECTIVE: The main aim of this study was to determine whether H-PACT offers a better patient experience than standard VHA primary care. RESEARCH DESIGN: We used multivariable logistic regressions to estimate differences in the probability of reporting positive primary care experiences on a national survey. SUBJECTS: Homeless-experienced survey respondents enrolled in H-PACT (n=251) or standard primary care in facilities with H-PACT available (n=1527) and facilities without H-PACT (n=10,079). MEASURES: Patient experiences in 8 domains from the Consumer Assessment of Healthcare Provider and Systems surveys. Domain scores were categorized as positive versus nonpositive. RESULTS: H-PACT patients were less likely than standard primary care patients to be female, have 4-year college degrees, or to have served in recent military conflicts; they received more primary care visits and social services. H-PACT patients were more likely than standard primary care patients in the same facilities to report positive experiences with access [adjusted risk difference (RD)=17.4], communication (RD=13.9), office staff (RD=13.1), provider ratings (RD=11.0), and comprehensiveness (RD=9.3). Standard primary care patients in facilities with H-PACT available were more likely than those from facilities without H-PACT to report positive experiences with communication (RD=4.7) and self-management support (RD=4.6). CONCLUSIONS: Patient-centered medical homes designed to address the social determinants of health offer a better care experience for homeless patients, when compared with standard primary care approaches. The lessons learned from H-PACT can be applied throughout VHA and to other health care settings.

The Role of Primary Care Experiences in Obtaining Treatment for Depression.

BACKGROUND: Managing depression in primary care settings has increased with the rise of integrated models of care, such as patient-centered medical homes (PCMHs). The relationship between patient experience in PCMH settings and receipt of depression treatment is unknown. OBJECTIVE: In a large sample of Veterans diagnosed with depression, we examined whether positive PCMH experiences predicted subsequent initiation or continuation of treatment for depression. DESIGN AND PARTICIPANTS: We conducted a lagged cross-sectional study of depression treatment among Veterans with depression diagnoses (n = 27,362) in the years before (Y1) and after (Y2) they completed the Veterans Health Administration's national 2013 PCMH Survey of Healthcare Experiences of Patients. MAIN MEASURES: We assessed patient experiences in four domains, each categorized as positive/moderate/negative. Depression treatment, determined from administrative records, was defined annually as 90 days of antidepressant medications or six psychotherapy visits. Multivariable logistic regressions measured associations between PCMH experiences and receipt of depression treatment in Y2, accounting for treatment in Y1. KEY RESULTS: Among those who did not receive depression treatment in Y1 (n = 4613), positive experiences in three domains (comprehensiveness, shared decision-making, self-management support) predicted greater initiation of treatment in Y2. Among those who received depression treatment in Y1 (n = 22,749), positive or moderate experiences in four domains (comprehensiveness, care coordination, medication decision-making, self-management support) predicted greater continuation of treatment in Y2. CONCLUSIONS: In a national PCMH setting, patient experiences with integrated care, including care coordination, comprehensiveness, involvement in shared decision-making, and self-management support predicted patients' subsequent initiation and continuation of depression treatment over time-a relationship that could affect physical and mental health outcomes.

Differences in Experiences With Care Between Homeless and Nonhomeless Patients in Veterans Affairs Facilities With Tailored and Nontailored Primary Care Teams.

BACKGROUND: Homeless patients describe poor experiences with primary care. In 2012, the Veterans Health Administration (VHA) implemented homeless-tailored primary care teams (Homeless Patient Aligned Care Team, HPACTs) that could improve the primary care experience for homeless patients. OBJECTIVE: To assess differences in primary care experiences between homeless and nonhomeless Veterans receiving care in VHA facilities that had HPACTs available (HPACT facilities) and in VHA facilities lacking HPACTs (non-HPACT facilities). RESEARCH DESIGN: We used multivariable multinomial regressions to estimate homeless versus nonhomeless patient differences in primary care experiences (categorized as negative/moderate/positive) reported on a national VHA survey. We compared the homeless versus nonhomeless risk differences (RDs) in reporting negative or positive experiences in 25 HPACT facilities versus 485 non-HPACT facilities. SUBJECTS: Survey respondents from non-HPACT facilities (homeless: n=10,148; nonhomeless: n=309,779) and HPACT facilities (homeless: n=2022; nonhomeless: n=20,941). MEASURES: Negative and positive experiences with access, communication, office staff, provider rating, comprehensiveness, coordination, shared decision-making, and self-management support. RESULTS: In non-HPACT facilities, homeless patients reported more negative and fewer positive experiences than nonhomeless patients. However, these patterns of homeless versus nonhomeless differences were reversed in HPACT facilities for the domains of communication (positive experience RDs in non-HPACT versus HPACT facilities=-2.0 and 2.0, respectively); comprehensiveness (negative RDs=2.1 and -2.3), shared decision-making (negative RDs=1.2 and -1.8), and self-management support (negative RDs=0.1 and -4.5; positive RDs=0.5 and 8.0). CONCLUSIONS: VHA facilities with HPACT programs appear to offer a better primary care experience for homeless versus nonhomeless Veterans, reversing the pattern of relatively poor primary care experiences often associated with homelessness.

Climate change can alter predator-prey dynamics and population viability of prey.

For many organisms, climate change can directly drive population declines, but it is less clear how such variation may influence populations indirectly through modified biotic interactions. For instance, how will climate change alter complex, multi-species relationships that are modulated by climatic variation and that underlie ecosystem-level processes? Caribou (Rangifer tarandus), a keystone species in Newfoundland, Canada, provides a useful model for unravelling potential and complex long-term implications of climate change on biotic interactions and population change. We measured cause-specific caribou calf predation (1990-2013) in Newfoundland relative to seasonal weather patterns. We show that black bear (Ursus americanus) predation is facilitated by time-lagged higher summer growing degree days, whereas coyote (Canis latrans) predation increases with current precipitation and winter temperature. Based on future climate forecasts for the region, we illustrate that, through time, coyote predation on caribou calves could become increasingly important, whereas the influence of black bear would remain unchanged. From these predictions, demographic projections for caribou suggest long-term population limitation specifically through indirect effects of climate change on calf predation rates by coyotes. While our work assumes limited impact of climate change on other processes, it illustrates the range of impact that climate change can have on predator-prey interactions. We conclude that future efforts to predict potential effects of climate change on populations and ecosystems should include assessment of both direct and indirect effects, including climate-predator interactions.

A national evaluation of homeless and nonhomeless veterans' experiences with primary care.

Persons who are homeless, particularly those with mental health and/or substance use disorders (MHSUDs), often do not access or receive continuous primary care services. In addition, negative experiences with primary care might contribute to homeless persons' avoidance and early termination of MHSUD treatment. The patient-centered medical home (PCMH) model aims to address care fragmentation and improve patient experiences. How homeless persons with MHSUDs experience care within PCMHs is unknown. This study compared the primary care experiences of homeless and nonhomeless veterans with MHSUDs receiving care in the Veterans Health Administration's medical home environment, called Patient Aligned Care Teams. The sample included VHA outpatients who responded to the national 2013 PCMH-Survey of Health Care Experiences of Patients (PCMH-SHEP) and had a past-year MSHUD diagnosis. Veterans with evidence of homelessness (henceforth "homeless") were identified through VHA administrative records. PCMH-SHEP survey respondents included 67,666 veterans with MHSUDs (9.2% homeless). Compared with their nonhomeless counterparts, homeless veterans were younger, more likely to be non-Hispanic Black and nonmarried, had less education, and were more likely to live in urban areas. Homeless veterans had elevated rates of most MHSUDs assessed, indicating significant co-occurrence. After controlling for these differences, homeless veterans reported more negative and fewer positive experiences with communication; more negative provider ratings; and more negative experiences with comprehensiveness, care coordination, medication decision-making, and self-management support than nonhomeless veterans. Homeless persons with MHSUDs may need specific services that mitigate negative care experiences and encourage their continuation in longitudinal primary care services. (PsycINFO Database Record

Loss of connectivity among island-dwelling Peary caribou following sea ice decline.

Global warming threatens to reduce population connectivity for terrestrial wildlife through significant and rapid changes to sea ice. Using genetic fingerprinting, we contrasted extant connectivity in island-dwelling Peary caribou in northern Canada with continental-migratory caribou. We next examined if sea-ice contractions in the last decades modulated population connectivity and explored the possible impact of future climate change on long-term connectivity among island caribou. We found a strong correlation between genetic and geodesic distances for both continental and Peary caribou, even after accounting for the possible effect of sea surface. Sea ice has thus been an effective corridor for Peary caribou, promoting inter-island connectivity and population mixing. Using a time series of remote sensing sea-ice data, we show that landscape resistance in the Canadian Arctic Archipelago has increased by approximately 15% since 1979 and may further increase by 20-77% by 2086 under a high-emission scenario (RCP8.5). Under the persistent increase in greenhouse gas concentrations, reduced connectivity may isolate island-dwelling caribou with potentially significant consequences for population viability.

Racial/Ethnic Differences in Primary Care Experiences in Patient-Centered Medical Homes among Veterans with Mental Health and Substance Use Disorders.

BACKGROUND: Patient-Centered Medical Homes (PCMH) may be effective in managing care for racial/ethnic minorities with mental health and/or substance use disorders (MHSUDs). How such patients experience care in PCMH settings is relatively unknown. OBJECTIVE: We aimed to examine racial/ethnic differences in experiences with primary care in PCMH settings among Veterans with MHSUDs. DESIGN: We used multinomial regression methods to estimate racial/ethnic differences in PCMH experiences reported on a 2013 national survey of Veterans Affairs patients. PARTICPANTS: Veterans with past-year MHSUD diagnoses (n = 65,930; 67 % White, 20 % Black, 11 % Hispanic, 1 % American Indian/Alaska Native[AI/AN], and 1 % Asian/Pacific Island[A/PI]). MAIN MEASURES: Positive and negative experiences from the Consumer Assessment of Healthcare Providers and Systems (CAHPS) PCMH Survey. RESULTS: Veterans with MHSUDs reported the lowest frequency of positive experiences with access (22 %) and the highest frequency of negative experiences with self-management support (30 %) and comprehensiveness (16 %). Racial/ethnic differences (as compared to Whites) were observed in all seven healthcare domains (p values < 0.05). With access, Blacks and Hispanics reported more negative (Risk Differences [RDs] = 2 .0;3.6) and fewer positive (RDs = -2 .3;-2.3) experiences, while AI/ANs reported more negative experiences (RD = 5.7). In communication, Blacks reported fewer negative experiences (RD = -1.3); AI/ANs reported more negative (RD = 3.6) experiences; and AI/ANs and APIs reported fewer positive (RD = -6.5, -6.7) experiences. With office staff, Hispanics reported fewer positive experiences (RDs = -3.0); AI/ANs and A/PIs reported more negative experiences (RDs = 3.4; 3.7). For comprehensiveness, Blacks reported more positive experiences (RD = 3.6), and Hispanics reported more negative experiences (RD = 2.7). Both Blacks and Hispanics reported more positive (RDs = 2.3; 4.2) and fewer negative (RDs = -1.8; -1.9) provider ratings, and more positive experiences with decision making (RDs = 2.4; 3.0). Blacks reported more positive (RD = 3.9) and fewer negative (RD = -5.1) experiences with self-management support. CONCLUSIONS: In a national sample of Veterans with MHSUDs, potential deficiencies were observed in access, self-management support, and comprehensiveness. Racial/ethnic minorities reported worse experiences than Whites with access, comprehensiveness, communication, and office staff helpfulness/courtesy.

Phase-dependent climate-predator interactions explain three decades of variation in neonatal caribou survival.

Climate can have direct and indirect effects on population dynamics via changes in resource competition or predation risk, but this influence may be modulated by density- or phase-dependent processes. We hypothesized that for ungulates, climatic conditions close to parturition have a greater influence on the predation risk of neonates during population declines, when females are already under nutritional stress triggered by food limitation. We examined the presence of phase-dependent climate-predator (PDCP) interactions on neonatal ungulate survival by comparing spatial and temporal fluctuations in climatic conditions, cause-specific mortality and per capita resource limitation. We determined cause-specific fates of 1384 caribou (Rangifer tarandus) from 10 herds in Newfoundland, spanning more than 30 years during periods of numerical increase and decline, while exposed to predation from black bears (Ursus americanus) and coyotes (Canis latrans). We conducted Cox proportional hazards analysis for competing risks, fit as a function of weather metrics, to assess pre- and post-partum climatic influences on survival on herds in population increase and decline phases. We used cumulative incidence functions to compare temporal changes in risk from predators. Our results support our main hypothesis; when caribou populations increased, weather conditions preceding calving were the main determinants of cause-specific mortality, but when populations declined, weather conditions during calving also influenced predator-driven mortality. Cause-specific analysis showed that weather conditions can differentially affect predation risk between black bears and coyotes with specific variables increasing the risk from one species and decreasing the risk from the other. For caribou, nutritional stress appears to increase predation risk on neonates, an interaction which is exacerbated by susceptibility to climatic events. These findings support the PDCP interactions framework, where maternal body condition influences susceptibility to climate-related events and, subsequently, risk from predation.

Patterns of sex and racial/ethnic differences in patient health care experiences in US Veterans Affairs hospitals.

BACKGROUND: Few studies have assessed sex or racial/ethnic differences in inpatient experiences in the Veterans Affairs (VA) Healthcare System. OBJECTIVES: This study aimed to compare inpatient experiences by sex and race/ethnicity within and between VA hospitals. RESEARCH DESIGN: We used mixed-effects multinomial regression to assess within-facility and between-facility sex and racial/ethnic differences in the 2010 VA Survey of Healthcare Experiences of Patients. SUBJECTS: 50,471 respondents from 144 VA hospitals (4.5% female; 75.4% non-Hispanic white, 14.7% non-Hispanic black, 5.4% Hispanic, and 4.4% other race/ethnicity). MEASURES: Negative and positive patient-reported experiences in 13 health care domains were included. RESULTS: Adjusted within-facility sex differences indicated that women reported more negative and less positive experiences than men in 4 domains, and less negative and more positive experiences on domains related to noise and privacy. Patients at facilities with more female patients reported more negative and less positive experiences in 4 domains. Blacks and Hispanics reported less negative and/or more positive experiences than whites within the same facility, although patients at facilities with more black and Hispanic patients reported more negative and less positive experiences overall. There were few and inconsistent within-facility differences between other racial/ethnic patients and whites. Patients at facilities with more other racial/ethnic patients reported slightly less negative and more positive experiences. CONCLUSIONS: Male, black, and Hispanic patients treated in VA hospitals tend to report more positive experiences than female and white patients treated at the same facilities. However, less positive experiences are reported by patients overall in hospitals that serve larger populations of women and racial/ethnic minorities.

Predicting local and non-local effects of resources on animal space use using a mechanistic step selection model.

Predicting space use patterns of animals from their interactions with the environment is fundamental for understanding the effect of habitat changes on ecosystem functioning. Recent attempts to address this problem have sought to unify resource selection analysis, where animal space use is derived from available habitat quality, and mechanistic movement models, where detailed movement processes of an animal are used to predict its emergent utilization distribution. Such models bias the animal's movement towards patches that are easily available and resource-rich, and the result is a predicted probability density at a given position being a function of the habitat quality at that position. However, in reality, the probability that an animal will use a patch of the terrain tends to be a function of the resource quality in both that patch and the surrounding habitat.We propose a mechanistic model where this non-local effect of resources naturally emerges from the local movement processes, by taking into account the relative utility of both the habitat where the animal currently resides and that of where it is moving. We give statistical techniques to parametrize the model from location data and demonstrate application of these techniques to GPS location data of caribou (Rangifer tarandus) in Newfoundland.Steady-state animal probability distributions arising from the model have complex patterns that cannot be expressed simply as a function of the local quality of the habitat. In particular, large areas of good habitat are used more intensively than smaller patches of equal quality habitat, whereas isolated patches are used less frequently. Both of these are real aspects of animal space use missing from previous mechanistic resource selection models.Whilst we focus on habitats in this study, our modelling framework can be readily used with any environmental covariates and therefore represents a unification of mechanistic modelling and step selection approaches to understanding animal space use.

Understanding racial and ethnic differences in patient experiences with outpatient health care in Veterans Affairs Medical Centers.

BACKGROUND: Racial and ethnic differences in patient health care experiences have not been well examined in the Veterans Affairs (VA) Healthcare System. OBJECTIVES: To examine racial/ethnic differences in outpatient health care experiences within and between VA medical facilities. RESEARCH DESIGN: We assessed within-facility and between-facility racial/ethnic differences in responses to the 2010 VA Survey of Healthcare Experiences of Patients using mixed-effects multinomial regression. SUBJECTS: A total of 211,459 respondents (53.2%) to a random survey of outpatients from 910 VA medical facilities (71.9% non-Hispanic white, 15.1% non-Hispanic black, 6.4% Hispanic, and 6.7% Other race/ethnicity). MEASURES: Negative and positive patient-reported experiences in 8 domains of health care. RESULTS: Between-facility effects for black race were higher for 7 domains of negative experiences [risk differences (RDs): 0.37% to 1.64%] and lower for 6 domains of positive experiences (RDs: -0.69% to -2.54%). Between-facility effects for Hispanic ethnicity were higher for 5 domains of negative experiences (RDs: 0.60%-1.34%) and lower for 5 domains of positive experiences (RDs: -1.00% to -1.88%). Hispanic ethnicity was also associated with higher within-facility rates of positive experiences for 5 domains of care (RDs: 2.97%-4.08%). Other race/ethnicity was associated with significantly higher within-facility rates of negative experiences (RDs: 2.04%-3.95%) and lower rates of positive experiences for all 8 domains (RDs: -2.05% to -4.70%). CONCLUSIONS: In a national random sample of Veterans managed in the VA Healthcare System, we demonstrated significant within-facility and between-facility racial and ethnic differences in outpatient health care experiences, with differing patterns for each minority group.

Phylogeography and post-glacial recolonization in wolverines (Gulo gulo) from across their circumpolar distribution.

Interglacial-glacial cycles of the Quaternary are widely recognized in shaping phylogeographic structure. Patterns from cold adapted species can be especially informative - in particular, uncovering additional glacial refugia, identifying likely recolonization patterns, and increasing our understanding of species' responses to climate change. We investigated phylogenetic structure of the wolverine, a wide-ranging cold adapted carnivore, using a 318 bp of the mitochondrial DNA control region for 983 wolverines (n=209 this study, n=774 from GenBank) from across their full Holarctic distribution. Bayesian phylogenetic tree reconstruction and the distribution of observed pairwise haplotype differences (mismatch distribution) provided evidence of a single rapid population expansion across the wolverine's Holarctic range. Even though molecular evidence corroborated a single refugium, significant subdivisions of population genetic structure (0.01< ΦST <0.99, P<0.05) were detected. Pairwise ΦST estimates separated Scandinavia from Russia and Mongolia, and identified five main divisions within North America - the Central Arctic, a western region, an eastern region consisting of Ontario and Quebec/Labrador, Manitoba, and California. These data are in contrast to the nearly panmictic structure observed in northwestern North America using nuclear microsatellites, but largely support the nuclear DNA separation of contemporary Manitoba and Ontario wolverines from northern populations. Historic samples (c. 1900) from the functionally extirpated eastern population of Quebec/Labrador displayed genetic similarities to contemporary Ontario wolverines. To understand these divergence patterns, four hypotheses were tested using Approximate Bayesian Computation (ABC). The most supported hypothesis was a single Beringia incursion during the last glacial maximum that established the northwestern population, followed by a west-to-east colonization during the Holocene. This pattern is suggestive of colonization occurring in accordance with glacial retreat, and supports expansion from a single refugium. These data are significant relative to current discussions on the conservation status of this species across its range.

The many faces of population density.

Population density, one of the most fundamental demographic attributes, may vary systematically with spatial scale, but this scale-sensitivity is incompletely understood. We used a novel approach-based on fully censused and mapped distributions of eastern grey squirrel (Sciurus carolinensis) dreys, beaver (Castor canadensis) lodges, and moose (Alces alces)--to explore the scale-dependence of population density and its relationship to landscape features. We identified population units at several scales, both objectively, using cluster analysis, and arbitrarily, using artificial bounds centred on high-abundance sites. Densities declined with census area. For dreys, this relationship was stronger in objective versus arbitrary population units. Drey density was inconsistently related to patch area, a relationship that was positive for all patches but negative when non-occupied patches were excluded. Drey density was negatively related to the proportion of green-space and positively related to the density of buildings or roads, relationships that were accentuated at coarser scales. Mean drey densities were more sensitive to scale when calculated as organism-weighted versus area-weighted averages. Greater understanding of these scaling effects is required to facilitate comparisons of population density across studies.

Fuzzy structure and spatial dynamics of a declining woodland caribou population.

Examining both spatial and temporal variation can provide insights into population limiting factors. We investigated the relative spatial and temporal changes in range use and mortality within the Red Wine Mountains caribou herd, a population that declined by approximately 75% from the 1980s to the 1990s. To extract the spatial structure of the population, we applied fuzzy cluster analysis, a method which assigns graded group membership, to space use of radio-tracked adult females, and compared these results to a hard classification based on sums-of-squares agglomerative clustering. Both approaches revealed four subpopulations. Based on the subpopulation assignments, we apportioned the number of animals, radio-days, calving events and mortalities across subpopulations before and after the decline. The results indicated that, as the herd declined, subpopulations were disproportionately affected. In general, subpopulations with the greatest range overlap with migratory caribou from the George River herd experienced comparative reductions in activity and increased mortality. The subpopulation with the least overlap exhibited the converse pattern. The infra-population imbalances were more pronounced when hard clustering was employed. Our results reiterate that refugia from other ungulates may be important in the persistence of taiga-dwelling caribou. We propose that changes across time and space are valuable assays of localised demographic change, especially where individuals exhibit spatial hyperdispersion and site fidelity.