Substantial Geographic Variation Research Articles

What drives health-care spending in China? A nationwide decomposition analysis

ABSTRACT In this study, we explore the geographic variation in health-care spending and its driving factors in China, using a nationwide and claim-level sample of inpatients ensured under the urban basic medical insurance schemes in 2010. We show geographic variation in health-care spending is substantial in China and is significantly larger than Medicare spending in the US. The substantial geographic variation is primarily driven by the quantity variation. We also discuss the potential correlates of the quantity of health care at the city level. The findings imply possible allocation inefficiency in China’s current urban health-care system.

Cost-effectiveness of medical migration for chronic kidney disease: a national cross-sectional study in China

BackgroundThe phenomenon of medical migration is common in China. Due to the limited capacity and substantial geographical variation in medical practice, patients with chronic kidney disease (CKD) travel more frequently to seek medical care. We aimed to assess the cost-effectiveness of medical migration for CKD patients in China and provide real-world evidence for the allocation of CKD resources.MethodsRecords of patients with CKD between January 2014 and December 2018 were extracted from a large national database. A patient is defined as a medical migrant if she travelled across the provincial border to a non-residential province to be admitted for inpatient care. The propensity score matching method is used to estimate the effect of medical migration on medical expenditure, length of hospital stay, and in-hospital mortality. The cost-effectiveness is evaluated by comparing the estimated cost per life saved with contemporaneous estimates of the value of a statistical life.ResultsAmong 4,392,650 hospitalizations with CKD, medical migrants accounted for 4.9% in 2018. Migrant patients were estimated to incur a 26.35% increase in total medical expenditure, experience a 0.24-percentage-points reduction in in-hospital mortality rates, and a 0.49-days reduction in length of hospital stay compared to non-migrant patients. Overall, medical migration among CKD patients incurred an average of 1 million yuan per life saved, which accounted for 20–40% of contemporaneous estimates of the value of a statistical life. Compared with migrant patients with self-payment and commercial insurance, migrant patients with public health insurance (urban basic medical insurance and new rural co-operative medical care) incurred lower cost per life saved. Cost per life saved for CKD patients was similar between female and male, lower among older population, and varied substantially across regions.ConclusionsThe medical care seeking behaviors of CKD patients was prominent and medical resources of kidney care were unevenly allocated across regions. Medical migration led to a reduction in mortality, but was associated with higher medical expenditure. It is imperative to reduce the regional disparity of medical resources and improve the clinical capacity. Our study shows that it is imperative to prioritize resource allocation toward improving kidney health and regional health care planning.

And Yet It Moves: Intergenerational Mobility in Italy

We estimate intergenerational income mobility in Italy using administrative data from tax returns. Our estimates of mobility are higher than prior work using survey data and indirect methods. The rankrank slope of parent-child income is 0.22, compared to 0.18 in Denmark and 0.34 in the United States. The probability that a child reaches the top quintile of the national income distribution starting from a family in the bottom quintile is 0.11. We uncover substantial geographical variation: upward mobility is much stronger in northern Italy, where provinces have higher measured school quality, more stable families, and more favorable labor market conditions. (JEL D31, J31, J62, R23)

Transcatheter aortic valve implantation in patients with bicuspid valve morphology: a roadmap towards standardization.

Indications for transcatheter aortic valve implantation (TAVI) have expanded in many countries to include patients with aortic stenosis who are at low surgical risk, and a similar expansion to this cohort is anticipated elsewhere in the world, together with an increase in the proportion of patients with bicuspid aortic valve (BAV) morphology as the age of the patients being treated decreases. To date, patients with BAV have been excluded from major randomized trials of TAVI owing to anatomical considerations. As a consequence, BAV has been a relative contraindication to the use of TAVI in international guidelines. Although clinical experience and observational data are accumulating, BAV presents numerous anatomical challenges for successful TAVI, despite advances in device design. Furthermore, in those with BAV, substantial geographical variation exists in patient characteristics, clinical approach and procedural strategy. Therefore, in this Roadmap article, we summarize the existing evidence and provide consensus recommendations from an international group of experts on the application of TAVI in patients with BAV in advance of the anticipated growth in the use of this procedure in this challenging cohort of patients.

Fire-driven vegetation type conversion in Southern California.

One consequence of global change causing widespread concern is the possibility of ecosystem conversions from one type to another. A classic example of this is vegetation type conversion (VTC) from native woody shrublands to invasive annual grasslands in the biodiversity hotspot of Southern California. Although the significance of this problem is well recognized, understanding where, how much, and why this change is occurring remains elusive owing to differences in results from studies conducted using different methods, spatial extents, and scales. Disagreement has arisen particularly over the relative importance of short-interval fires in driving these changes. Chronosequence approaches that use space for time to estimate changes have produced different results than studies of changes at a site over time. Here we calculated the percentage woody and herbaceous cover across Southern California using air photos from ~1950 to 2019. We assessed the extent of woody cover change and the relative importance of fire history, topography, soil moisture, and distance to human infrastructure in explaining change across a hierarchy of spatial extents and regions. We found substantial net decline in woody cover and expansion of herbaceous vegetation across all regions, but the most dramatic changes occurred in the northern interior and southern coastal areas. Variables related to frequent, short-interval fire were consistently top ranked as the explanation for shrub to grassland type conversion, but low soil moisture and topographic complexity were also strong correlates. Despite the consistent importance of fire, there was substantial geographical variation in the relative importance of drivers, and these differences resulted in different mapped predictions of VTC. This geographical variation is important to recognize for management decision-making and, in addition to differences in methodological design, may also partly explain differences in previous study results. The overwhelming importance of short-interval fire has management implications. It suggests that actions should be directed away from imposing fires to preventing fires. Prevention can be controlled through management actions that limit ignitions, fire spread, and the damage sustained in areas that do burn. This study also demonstrates significant potential for changing fire regimes to drive large-scale, abrupt ecological change.

Il ruolo della tecnologia nella gestione del bambino e dell’adolescente con diabete di tipo 1

In Italy, it is estimated there are about 25,000 children and adolescents with type 1 diabetes between 0 and 18 years, most of whom using electronic devices for blood glucose control. Among these many have chosen a sensor for measuring blood glucose, often integrated, or combined with an insulin pump, preferably included in (advanced) hybrid closed-loop systems, that increasingly resemble artificial pancreases. This technology has seen an enormous progress in the last two decades, making these tools fundamental for improving glycemic control and the quality of life of patients with diabetes and their families. However, major challenges remain, including cybersecurity vulnerability, cost, and accessibility, with a substantial geographical variation in access to diabetes technologies. The hope is that the very recent guidelines of SID, AMD and SIEDP will help to rationalize and improve access to available technologies.

Charges for Distal Radius Fracture Fixation Are Affected by Fracture Pattern, Location of Service, and Anesthesia Type.

This study sought to characterize charges associated with operative treatment of distal radius fractures and identify sources of variation contributing to overall cost. A retrospective study was performed using the New York Statewide Planning and Research Cooperative System database from 2009-2017. Outpatient claims were identified using the International Classification of Diseases-9/10-Clinical Modification diagnosis codes for distal radius fixation surgery. A multivariable mixed model regression was performed to identify variables contributing to total charges of the claim, including patient demographics, anesthesia method, surgery location (ambulatory surgery center [ASC] versus a hospital outpatient department [HOPD], operation time, insurance type, Charlson Comorbidity Index, and billed procedure codes. A total of 9029 claims were included, finding older age, private primary insurance, surgery performed in a HOPD, and use of local anesthesia (vs general or regional) associated with increased total charges. There was no difference between gender, race, or ethnicity. Additionally, open reduction and internal fixation (ORIF), increased operative time/fracture complexity, and use of perioperative medications contributed significantly to overall costs. Charges for distal radius fracture surgery performed in a HOPD were 28.3% higher than compared to an ASC, and cases with local anesthesia had higher billed claims compared to regional or general anesthesia. Furthermore, charges for percutaneous fixation were 54.6% lower than ORIF of extraarticular fracture, and claims had substantial geographic variation. These findings may be used by providers and payers to help improve value of distal radius fracture care. Level III.

Variation in regional implantation patterns of cardiac implantable electronic device in Switzerland.

IntroductionThere is a substantial geographical variation in the rates of pacemaker (PM), implantable cardioverter defibrillator (ICD), and cardiac resynchronization therapy (CRT) device implantation across European countries. We assessed the extent of regional variation and potential determinants of such variation.MethodsWe conducted a population-based analysis using discharge data for PM/ICD/CRT implantations from all Swiss acute care hospitals during 2013–2016. We derived hospital service areas (HSA) by analyzing patient flows. We calculated age- and sex-standardized rates and quantified variation using the extremal quotient (EQ) and the systemic component of variation (SCV). We estimated the reduction in variance of crude implantation rates across HSAs using multilevel regression models, with incremental adjustment for age and sex, language, socioeconomic factors, population health, diabetes mellitus, and the density of cardiologists on the HSA level.ResultsWe analyzed implantations of 8129 PM, 1461 ICD, and 1411 CRT from 25 Swiss HSAs. The mean age- and sex-standardized implantation rate was 29 (range 8–57) per 100,000 persons for PM, 5 (1–9) for ICD, and 5 (2–8) for CRT. There was a very high variation in PM (EQ 7.0; SCV 12.6) and ICD (EQ 7.2; SCV 11.3) and a high variation in CRT implantation rates (EQ 3.9; SCV 7.1) across HSAs. Adjustments for age and sex, language, socioeconomic factors, population health, diabetes mellitus, and density of cardiologists explained 94% of the variance in ICD and 87.5% of the variance in CRT implantation rates, but only 36.3% of the variance in PM implantation rates. Women had substantially lower PM/ICD/CRT implantation rates than men.ConclusionSwitzerland has a very high regional variation in PM/ICD implantation and a high variation in CRT implantation rates. Women had substantially lower implantation rates than men. A large share of the variation in PM procedure rates remained unexplained which might reflect variations in physicians’ preferences and practices.

Blood Donation in Lebanon: A Six-Year Retrospective Study of a Decentralized Fragmented Blood Management System.

IntroductionIn developing countries, the lack of a sufficient and safe blood supply is a significant impediment to providing health care. Lebanon is notable for its absence of a Donor Management System to ensure continuous donor recruitment and scheduling. Herein, we report the findings of Lebanon's first large retrospective population-based study to investigate blood types and donation that is critical for managing community blood supply.MethodsThe non-remunerated voluntary blood donors were recruited by the non-profit organization “Donner Sang Compter”. The study spanned six years, from August 2015 to May 2021, and included 36,002 people from 18 districts throughout Lebanon's nine governorates.ResultsThe most prevalent blood type was A (42%), followed by O (37.48%), B (13.86%), and the AB group (6.84%). RhD+ groups were predominant (88.45%), with A+ being the most (37.84%) and AB- being the least prevalent (1.05%). Furthermore, blood type and donation profiling revealed a substantial geographical variation in the frequency of blood groups, despite the relatively small country’s area. As for blood donation, when gender and age were considered, young male donors dominated the pool across the country.ConclusionThis study on blood type prevalence and blood donor demographics may pave the way for the development of a more coherent and integrated blood management system in Lebanon, as opposed to the fragmented and decentralized system now in existence. These findings also provide crucial clinical information for the country's future transfusion medicine policies and practices, which is vital in such a precarious part of the world.

Municipal Characteristics of In-Home Death Among Care-Dependent Older Japanese Adults

The provision of in-home and community end-of-life care has emerged as an important policy issue for aging populations around the world. Despite most patients expressing the wish to die at home (as opposed to in the hospital), substantial geographic variation persists in the prevalence of in-home death at the end of life. To assess the association of municipal characteristics with variation in the place of death among care-dependent older people in Japan. In this cross-sectional study using multilevel logistic regression, analyses were performed using national claims data under Japan's long-term care insurance system. The study population included long-term care insurance beneficiaries 65 years and older who died in 2015, excluding those who died from external causes, such as unintentional injuries. Data analyses were conducted from January 1 to April 31, 2021. Predisposing, enabling, and need factors at the individual and municipal levels according to a behavioral model. The outcome was whether individuals died at home or not. This cross-sectional study analyzed 544 836 decedents (median [IQR] age, 87 [81-91] years; 300 142 [55.1%] female). The proportion of in-home deaths was 10.3%. In the multilevel null model, 7.2% of the variance in the place of death was associated with municipal-level characteristics. Municipal characteristics were associated with more of the variance than were prefectural characteristics (2.7%). The largest proportional change (7.3%) in variance at the municipality level was observed when enabling factors (ie, medical and long-term care resources) were added to the model. Municipalities with a high proportion of in-home death were more likely to have a higher supply of clinics, physicians, and care workers providing in-home services per population, as well as a lower number of hospital beds and long-term care facility workers per population. In this cross-sectional study, municipal characteristics explained a substantial proportion of the geographic variance in in-home death in Japan. These results suggest that municipal policy makers need to ensure an adequate supply of clinics, physicians, and care workers providing in-home services to meet the preferences of care-dependent older people who wish to spend their final days at home.

Variation in early diffusion of sacubitril/valsartan and implications for understanding novel drug diffusion.

In the PARADIGM-HF trial, sacubitril/valsartan demonstrated a 20% reduction in mortality and heart failure hospitalization compared with standard angiotensin-converting enzyme inhibitor therapy. Despite this and a class I indication, drug diffusion has been much slower than anticipated. This study aims to examine the variation in early diffusion of sacubitril/valsartan and describe the factors associated with high and low rates of early use. Annual, cross-sectional analyses between January 2016 and December 2018. We created a nationally representative cohort of Medicare fee-for-service beneficiaries with heart failure with reduced ejection fraction fully enrolled in parts A, B, and D for at least 1 year between 2016 and 2018. Sacubitril/valsartan use was determined using National Drug Codes. We generated age, sex, and race-adjusted rates of sacubitril/valsartan prescribing by hospital referral region from 2016 to 2018. We also examined the factors associated with high and low rates of early use. Early use rates of sacubitril/valsartan were low: 1.9% in 2016, 3.3% in 2017, and 4.0% in 2018. Even after controlling for out-of-pocket co-payments, there was substantial geographic variation in early use, with most early use concentrated in the Northeast and South. There has been substantial variation in the early diffusion of sacubitril/valsartan. In addition to drug cost, geographic prescribing patterns appear to play a major role in early drug diffusion.

The potential impact of country-level migration networks on HIV epidemics in sub-Saharan Africa: the case of Botswana.

Generalised HIV epidemics in sub-Saharan Africa show substantial geographical variation in prevalence, which is considered when designing epidemic control strategies. We hypothesise that the migratory behaviour of the general population of countries in sub-Saharan Africa could have a substantial effect on HIV epidemics and challenge the elimination effort. To test this hypothesis, we used census data from 2017 to identify, construct, and visualise the migration network of the population of Botswana, which has one of the most severe HIV epidemics worldwide. We found that, over 12 months, approximately 14% of the population moved their residency from one district to another. Four types of migration occurred: urban-to-urban, rural-to-urban, urban-to-rural, and rural-to-rural. Migration is leading to a marked geographical redistribution of the population, causing high rates of population turnover in some areas, and further concentrating the population in urban areas. The migration network could potentially be having a substantial effect on the HIV epidemic of Botswana: changing the location of high-transmission areas, generating cross-country transmission corridors, creating source-sink dynamics, and undermining control strategies. Large-scale migration networks could present a considerable challenge to eliminating HIV in Botswana and in other countries in sub-Saharan Africa, and should be considered when designing epidemic control strategies.

Geographic Pattern of Typhoid Fever in India: A Model-Based Estimate of Cohort and Surveillance Data.

BackgroundTyphoid fever remains a major public health problem in India. Recently, the Surveillance for Enteric Fever in India program completed a multisite surveillance study. However, data on subnational variation in typhoid fever are needed to guide the introduction of the new typhoid conjugate vaccine in India.MethodsWe applied a geospatial statistical model to estimate typhoid fever incidence across India, using data from 4 cohort studies and 6 hybrid surveillance sites from October 2017 to March 2020. We collected geocoded data from the Demographic and Health Survey in India as predictors of typhoid fever incidence. We used a log linear regression model to predict a primary outcome of typhoid incidence.ResultsWe estimated a national incidence of typhoid fever in India of 360 cases (95% confidence interval [CI], 297–494) per 100 000 person-years, with an annual estimate of 4.5 million cases (95% CI, 3.7–6.1 million) and 8930 deaths (95% CI, 7360–12 260), assuming a 0.2% case-fatality rate. We found substantial geographic variation of typhoid incidence across the country, with higher incidence in southwestern states and urban centers in the north.ConclusionsThere is a large burden of typhoid fever in India with substantial heterogeneity across the country, with higher burden in urban centers.

Abstract 13000: Quality of Care and In-Hospital Outcomes of Patients Hospitalized for Heart Failure With Reduced Ejection Fraction During the COVID-19 Pandemic: Findings From the Get With the Guidelines-Heart Failure Registry

Introduction: COVID-19’s impact on in-hospital care quality and outcomes of patients hospitalized with acute heart failure (HF) has not been systematically evaluated nationally. Methods: Patients hospitalized with HF with ejection fraction (EF) <40% in the AHA GWTG-HF registry during the pandemic (3/1/2020 - 4/1/ 2021) and pre-pandemic (2/1/2019 - 2/29/2020) periods were included. Adherence to HF process of care measures, in-hospital mortality, and length of stay (LOS) were compared in the pre-pandemic vs pandemic period and among hospitalized HF patients with vs without COVID-19 across both periods. Results: 40,005 pre-pandemic and 35,561 pandemic period patients admitted across 346 centers (median age 68, 33% women, 58% White) were included. There were no differences in clinical characteristics, comorbidities, presentation vital signs, or EF during the pandemic vs pre-pandemic periods. Among process of care measures, utilization of guideline-directed medical therapy at discharge was comparable across both periods. In contrast, rates of ICD placement or prescription and blood pressure control at discharge were lower during the pandemic (vs pre-pandemic period) ( Table ). In-hospital death (2.5% vs. 3.0%, p<0.001) and LOS (mean 5.4 vs. 5.7 days, p=0.008) were higher during the pandemic vs pre-pandemic. Substantial geographic variation was seen in the in-hospital death rates during the pandemic, with highest rates among patients hospitalized in the Northeast region (3.36%). Among HF patients hospitalized during the pandemic with COVID-19 (N = 527 [1.5%]), adherence to ICD placement or prescription at discharge and prescription of aldosterone antagonist or ACE/ARB/ARNi were lower, and risk of in-hospital death and length of stay were significantly higher than those without COVID-19. Conclusion: In-hospital mortality and adherence to certain quality measures worsened during COVID-19 pandemic among patients admitted for acute decompensated HFrEF.

Human density is associated with the increased prevalence of a generalist zoonotic parasite in mammalian wildlife.

Macroecological approaches can provide valuable insight into the epidemiology of globally distributed, multi-host pathogens. Toxoplasma gondii is a zoonotic protozoan that infects any warm-blooded animal, including humans, in almost every ecosystem worldwide. There is substantial geographical variation in T. gondii prevalence in wildlife populations and the mechanisms driving this variation are poorly understood. We implemented Bayesian phylogenetic mixed models to determine the association between species’ ecology, phylogeny and climatic and anthropogenic factors on T. gondii prevalence. Toxoplasma gondii prevalence data were compiled for free-ranging wild mammal species from 202 published studies, encompassing 45 079 individuals from 54 taxonomic families and 238 species. We found that T. gondii prevalence was positively associated with human population density and warmer temperatures at the sampling location. Terrestrial species had a lower overall prevalence, but there were no consistent patterns between trophic level and prevalence. The relationship between human density and T. gondii prevalence is probably mediated by higher domestic cat abundance and landscape degradation leading to increased environmental oocyst contamination. Landscape restoration and limiting free-roaming in domestic cats could synergistically increase the resiliency of wildlife populations and reduce wildlife and human infection risks from one of the world's most common parasitic infections.

The social determinants of depressive disorders in China

Depressive disorders are the second most prevalent disorder globally after cardiovascular disease, affecting more than 300 million people worldwide.1 Notably, the estimated prevalence of depressive disorders has substantial geographical variation, making a thorough assessment in each country necessary.2 As it is the most populous country in the world, nationally representative epidemiological data for depressive disorders in China are particularly important.

Time trends, geographic variation and risk factors for gastroschisis in Canada: A population-based cohort study 2006-2017.

BackgroundPrevious studies showed increases in rates of gastroschisis in Canada in the first decade of the 21st century.ObjectiveWe sought to examine the epidemiologic characteristics of gastroschisis in Canada in recent years.MethodsWe conducted a retrospective population‐based cohort study of all livebirths and stillbirths delivered in Canada (excluding Quebec) from 2006 to 2017, with information obtained from the Canadian Institute for Health Information. Gastroschisis rates by maternal age, region of residence, and maternal and infant characteristics were quantified using prevalence rate ratios (RR) and 95% confidence intervals (CI). Log‐binomial regression was used to quantify the associations between risk factors and gastroschisis.ResultsThere were 1314 gastroschisis cases among 3 364 116 births. The prevalence rate was 3.7 per 10 000 total births in 2006 and 3.4 per 10 000 total births in 2017, with substantial annual variation in rates. The proportion of mothers aged 20–24 years decreased from 16.5% in 2006 to 11.3% in 2017, while the proportion of mothers aged <20 years halved from 4.8% to 2.3%. The prevalence of gastroschisis at birth remained unchanged among mothers aged <20, 20–24 and 30–49 years but increased among mothers aged 25–29 years. The age‐adjusted prevalence rate of gastroschisis increased across the period (for 2016–2017 versus 2006–2007 rate ratio [RR] 1.28, 95% CI 1.05, 1.56), and there was substantial regional variation. Risk factors included problematic use of substances (RR 2.61, 95% CI 2.01, 3.39) and hypothyroidism (RR 2.76, 95% CI 1.56, 4.88). There was a North‐to‐South difference in gastroschisis prevalence (adjusted RR Far North compared with South 1.54, 95% CI 1.11, 2.15).ConclusionGastroschisis birth prevalence rates in Canada have stabilised in recent years compared with the increase documented previously. The substantial geographic variation and North‐to‐South difference in gastroschisis prevalence may indicate variation in socio‐economic status, lifestyle and nutritional patterns.

Seroprevalence of Cytomegalovirus and Associated Factors Among Preconception Women: A Cross-Sectional Nationwide Study in China.

Background: Cytomegalovirus seroconversion during pregnancy is common and has a substantial risk of congenital infection with longterm sequale. Screening during pregnancy or vaccination have not been shown to be effective for eliminating congenital infections. Preconception screening policy has not been evaluated adequately in a large scale. This nationwide study aimed to investigate epidemiological features of cytomegalovirus seropositivity and its geographic variation among Chinese women planning a pregnancy to gather epidemiological evidence as an essential for developing novel prevention strategies.Method: This cross-sectional sero-epidemiological survey enrolled women intending to become pregnant within 6 months in mainland China during 2010–2012. The primary outcomes in this study were cytomegalovirus Immunoglobulin G and M seropositivity. Secondary outcomes were the associations between Immunoglobulin G and Immunoglobulin M, with socio-demographic characteristics, including age, occupation, education level, place of residence, and ethnicity. The overall seropositivity and regional disparity was analyzed on the individual and regional level, respectively.Results: This study included data from 1,564,649 women from 31 provinces in mainland China. Among participants, 38.6% (n = 603,511) were cytomegalovirus immunoglobulin G+, 0.4% (n = 6,747) were immunoglobulin M+, and 0.2% (n = 2,879) were immunoglobulin M+ and immunoglobulin G+. On individual level, participant's age, ethnicity, and residing region were significantly associated with IgG+, IgM+, and IgM+IgG+ (P < 0.001), while occupation, education level, and place of residence were not statistically significant (P > 0.05). On regional level, cytomegalovirus immunoglobulin G and immunoglobulin M seropositivity was highest in the eastern region (49.5 and 0.5%, respectively), and lowest in the western region (26.9 and 0.4%, respectively). This geographic variation was also noted at the provincial level, characterized by higher provincial immunoglobulin M+ and immunoglobulin G+ rates associated with higher immunoglobulin G seropositivity. In the subgroup analysis of immunoglobulin G seropositivity, areas of higher immunoglobulin G positivity had a higher rate of immunoglobulin M+, indicating an expected increased risk of reinfection and primary infection.Conclusions: A substantial proportion of women (>60%) were susceptible to cytomegalovirus in preconception period in China, and immunoglobulin G seropositivity was seen at a low-medium level with substantial geographic variation. Integration of cytomegalovirus antibody testing in preconception screening program based on regional immunoglobulin G seropositivity, should be considered to promote strategies directed toward preventing sero-conversion during pregnancy to reduce the risk of this congenital infection.

Understanding the future of big sagebrush regeneration: challenges of projecting complex ecological processes

AbstractRegeneration is an essential demographic step that affects plant population persistence, recovery after disturbances, and potential migration to track suitable climate conditions. Challenges of restoring big sagebrush (Artemisia tridentata) after disturbances including fire‐invasive annual grass interactions exemplify the need to understand the complex regeneration processes of this long‐lived, woody species that is widespread across the semiarid western U.S. Projected 21st century climate change is expected to increase drought risks and intensify restoration challenges. A detailed understanding of regeneration will be crucial for developing management frameworks for the big sagebrush region in the 21st century. Here, we used two complementary models to explore spatial and temporal relationships in the potential of big sagebrush regeneration representing (1) range‐wide big sagebrush regeneration responses in natural vegetation (process‐based model) and (2) big sagebrush restoration seeding outcomes following fire in the Great Basin and the Snake River Plains (regression‐based model). The process‐based model suggested substantial geographic variation in long‐term regeneration trajectories with central and northern areas of the big sagebrush region remaining climatically suitable, whereas marginal and southern areas are becoming less suitable. The regression‐based model suggested, however, that restoration seeding may become increasingly more difficult, illustrating the particularly difficult challenge of promoting sagebrush establishment after wildfire in invaded landscapes. These results suggest that sustaining big sagebrush on the landscape throughout the 21st century may climatically be feasible for many areas and that uncertainty about the long‐term sustainability of big sagebrush may be driven more by dynamics of biological invasions and wildfire than by uncertainty in climate change projections. Divergent projections of the two models under 21st century climate conditions encourage further study to evaluate potential benefits of re‐creating conditions of uninvaded, unburned natural big sagebrush vegetation for post‐fire restoration seeding, such as seeding in multiple years and, for at least much of the northern Great Basin and Snake River Plains, the control of the fire‐invasive annual grass cycle.

Conservation planning for pollinators in the U.S. Great Plains: considerations of context, treatments, and scale

AbstractPopulations of many species of grassland‐associated butterflies, moths, and bumblebees in the Great Plains of North America are experiencing steep declines due to habitat loss and degradation—primarily conversion of grasslands to row‐crop agriculture and invasion of woody plants and exotic cool‐season grasses—and insecticide use. These declines are exacerbated by the generally limited dispersal ability of insects, which make local populations susceptible to extirpation following habitat fragmentation. Interest in pollinator conservation has grown substantially in recent years, but information to guide pollinator conservation across the region is limited. We used pollinator biology along with principles of landscape ecology and metapopulation dynamics to develop a simple decision matrix based on patch size and inter‐patch distances to guide landscape‐scale grassland conservation efforts in the U.S. northern Great Plains. When applied to spatial land cover data depicting potential pollinator habitat, the matrix uses landscape characteristics to guide placement of conservation treatments to help ensure persistence of target pollinator populations. Patch size and connectivity thresholds can be set to match characteristics of target species, but in all cases, local management will be necessary to ensure that fine‐grained features such as nectar sources and host plants are present. Applying the matrix to habitat layers for a nine‐state analysis region showed substantial geographic variation in conservation needs, opportunities, and potential treatments. We also demonstrate that non‐native planted cover such as alfalfa and certain grasslands enrolled in the Conservation Reserve Program can substantially enhance landscape structure by increasing grassland patch size and core area while decreasing distance between patches. Pollinators dependent on native prairie will also benefit from planted cover that provides nectar sources and serves as a buffer from pesticides associated with croplands. Consistent with the principles of strategic habitat conservation, targeted monitoring and research will be necessary to validate and adapt the model to meet local conditions.