Forrest Melton

Human risk of infection with Borrelia burgdorferi, the Lyme disease agent, in eastern United States.

The geographic pattern of human risk for infection with Borrelia burgdorferi sensu stricto, the tick-borne pathogen that causes Lyme disease, was mapped for the eastern United States. The map is based on standardized field sampling in 304 sites of the density of Ixodes scapularis host-seeking nymphs infected with B. burgdorferi, which is closely associated with human infection risk. Risk factors for the presence and density of infected nymphs were used to model a continuous 8 km×8 km resolution predictive surface of human risk, including confidence intervals for each pixel. Discontinuous Lyme disease risk foci were identified in the Northeast and upper Midwest, with a transitional zone including sites with uninfected I. scapularis populations. Given frequent under- and over-diagnoses of Lyme disease, this map could act as a tool to guide surveillance, control, and prevention efforts and act as a baseline for studies tracking the spread of infection.

The impacts of climate change on ecosystem structure and function

Recent climate-change research largely confirms the impacts on US ecosystems identified in the 2009 National Climate Assessment and provides greater mechanistic understanding and geographic specificity for those impacts. Pervasive climate-change impacts on ecosystems are those that affect productivity of ecosystems or their ability to process chemical elements. Loss of sea ice, rapid warming, and higher organic inputs affect marine and lake productivity, while combined impacts of wildfire and insect outbreaks decrease forest productivity, mostly in the arid and semi-arid West. Forests in wetter regions are more productive owing to warming. Shifts in species ranges are so extensive that by 2100 they may alter biome composition across 5–20% of US land area. Accelerated losses of nutrients from terrestrial ecosystems to receiving waters are caused by both winter warming and intensification of the hydrologic cycle. Ecosystem feedbacks, especially those associated with release of carbon dioxide and methane rel...

Climate and tick seasonality are predictors of Borrelia burgdorferi genotype distribution.

ABSTRACT The blacklegged tick, Ixodes scapularis, is of significant public health importance as a vector of Borrelia burgdorferi, the agent of Lyme borreliosis. The timing of seasonal activity of each immature I. scapularis life stage relative to the next is critical for the maintenance of B. burgdorferi because larvae must feed after an infected nymph to efficiently acquire the infection from reservoir hosts. Recent studies have shown that some strains of B. burgdorferi do not persist in the primary reservoir host for more than a few weeks, thereby shortening the window of opportunity between nymphal and larval feeding that sustains their enzootic maintenance. We tested the hypothesis that climate is predictive of geographic variation in the seasonal activity of I. scapularis, which in turn differentially influences the distribution of B. burgdorferi genotypes within the geographic range of I. scapularis. We analyzed the relationships between climate, seasonal activity of I. scapularis, and B. burgdorferi genotype frequency in 30 geographically diverse sites in the northeastern and midwestern United States. We found that the magnitude of the difference between summer and winter daily temperature maximums was positively correlated with the degree of seasonal synchrony of the two immature stages of I. scapularis. Genotyping revealed an enrichment of 16S-23S rRNA intergenic spacer restriction fragment length polymorphism sequence type 1 strains relative to others at sites with lower seasonal synchrony. We conclude that climate-associated variability in the timing of I. scapularis host seeking contributes to geographic heterogeneities in the frequencies of B. burgdorferi genotypes, with potential consequences for Lyme borreliosis morbidity.

Downscaled Climate Projections Suitable for Resource Management

The general circulation model (GCM) experiments conducted under the Coupled Model Intercomparison Project Phase 5 (CMIP5) [Taylor et al., 2012], which is being conducted in preparation for the Intergovernmental Panel on Climate Changes Fifth Assessment Report, provide fundamental data sets for assessing the effects of global climate change. However, efforts to assess regional or local effects of the projected changes in climate are often impeded by the coarse spatial resolution of the GCM outputs, as well as potential local or regional biases in GCM outputs [Fowler et al., 2007].

Looking forward: Applying an ecological model web to assess impacts of climate change

Abstract Climate change is a major threat to the worlds protected areas, yet the difficulty of making good predictions of the impacts of change constrains management, planning, and policy making. An important factor limiting development of these predictions is the inability of existing computer models, which simulate ecosystem and related processes, to easily exchange information. The ecological Model Web, now in the early stages of development, addresses this limitation. The Model Web will be an open-ended network of interoperable computer models and databases that use web services to communicate with one another and with end-users. Analogous to the World Wide Web, it will grow organically and opportunistically within a framework of broad goals and high-level standards. Making it easier for models to communicate will increase their collective power and the breadth of questions they can address, while providing web access to their results will facilitate greater extraction of societal benefits by managers, policy makers, and the public.

The future of evapotranspiration: Global requirements for ecosystem functioning, carbon and climate feedbacks, agricultural management, and water resources

The fate of the terrestrial biosphere is highly uncertain given recent and projected changes in climate. This is especially acute for impacts associated with changes in drought frequency and intensity on the distribution and timing of water availability. The development of effective adaptation strategies for these emerging threats to food and water security are compromised by limitations in our understanding of how natural and managed ecosystems are responding to changing hydrological and climatological regimes. This information gap is exacerbated by insufficient monitoring capabilities from local to global scales. Here, we describe how evapotranspiration (ET) represents the key variable in linking ecosystem functioning, carbon and climate feedbacks, agricultural management, and water resources, and highlight both the outstanding science and applications questions and the actions, especially from a space-based perspective, necessary to advance them.

Satellite Irrigation Management Support With the Terrestrial Observation and Prediction System: A Framework for Integration of Satellite and Surface Observations to Support Improvements in Agricultural Water Resource Management

In California and other regions vulnerable to water shortages, satellite-derived estimates of key hydrologic fluxes can support agricultural producers and water managers in maximizing the benefits of available water supplies. The Satellite Irrigation Management Support (SIMS) project combines NASAs Terrestrial Observation and Prediction System (TOPS), Landsat and MODIS satellite imagery, and surface sensor networks to map indicators of crop irrigation demand and develop information products to support irrigation management and other water use decisions. TOPS-SIMS provides the computing and data processing systems required to support automated, near real-time integration of observations from satellite and surface sensor networks, and generates data and information in formats that are convenient for agricultural producers, water managers, and other end users. Using the TOPS modeling framework to integrate data from multiple sensor networks in near real-time, SIMS currently maps crop fractional cover, basal crop coefficients, and basal crop evapotranspiration. Map products are generated at 30 m resolution on a daily basis over approximately 4 million ha of California farmland. TOPS-SIMS is a fully operational prototype, and a publicly available beta-version of the web interface is being pilot tested by farmers, irrigation consultants, and water managers in California. Data products are distributed via dynamic web services, which support both visual mapping and time-series queries, to allow users to obtain information on spatial and temporal patterns in crop canopy development and water requirements. TOPS-SIMS is an application framework that demonstrates the value of integrating multi-disciplinary Earth observation systems to provide benefits for water resource management.

Hydro-economic analysis of groundwater pumping for irrigated agriculture in California’s Central Valley, USA

As in many places, groundwater in California (USA) is the major alternative water source for agriculture during drought, so groundwater’s availability will drive some inevitable changes in the state’s water management. Currently, agricultural, environmental, and urban uses compete for groundwater, resulting in substantial overdraft in dry years with lowering of water tables, which in turn increases pumping costs and reduces groundwater pumping capacity. In this study, SWAP (an economic model of agricultural production and water use in California) and C2VISim (the California Department of Water Resources groundwater model for California’s Central Valley) are connected. This paper examines the economic costs of pumping replacement groundwater during drought and the potential loss of pumping capacity as groundwater levels drop. A scenario of three additional drought years continuing from 2014 show lower water tables in California’s Central Valley and loss of pumping capacity. Places without access to groundwater and with uncertain surface-water deliveries during drought are the most economically vulnerable in terms of crop revenues, employment and household income. This is particularly true for Tulare Lake Basin, which relies heavily on water imported from the Sacramento-San Joaquin Delta. Remote-sensing estimates of idle agricultural land between 2012 and 2014 confirm this finding. Results also point to the potential of a portfolio approach for agriculture, in which crop mixing and conservation practices have substantial roles.ZusammefassungWie in vielen anderen Regionen is Grundwasser auch in Kalifornien (USA) die wichtigste alternative Wasserresource fuer die Landwirtschaft waehrend anhaltender Duerre. Daher wird die Verfuegbarkeit des Grundwassers unvermeidlich die landesweite Wasserversorgung beeinflussen. Derzeit stehen landwirtschaftlicher, oekologischer, und urbaner Wasserbedarf in strengem Wettbewerb zueinander. Dies fuehrt zu langfristiger Leerung der Grundwasserleiter, hoeheren Pumpkosten, und geringer Pumpkapazitaet. Hier verwenden wir SWAP (ein agrar-oekonomisches Model der Landwirtschaft und derer Wassernutzung in Kalifornien) in Kombination mit C2VSim (das Grundwassermodell des kalifornischen Landeswasseramts fuer das kalifornische Grosse Zentraltal). In diesem Artikel werden die zusaetzlichen Pumpkosten und Brunnenneubaukosten abgeschaetzt die aufgrund der Grundwasserabsenkung waehrend einer Duerre eintreten. Ein Fortsetzung der derzeitigen Duerre fuer weiter drei Jahre zeigt die zusaetzliche Grundwasserabsenkung und die daraus entstehende Verringerung der Foerderkapazitaeten auf. Wo Grundwasser nicht verfuegbar ist und Oberflaehenwasserversorgung waehrend Duerreperioden unsicher sind, ergeben sich besonders verwundbare landwirtschaftliche Bereiche, vor allem in Bezug auf wirtschaftliche Leistung, Arbeitsplaetze, und Haushaltseinkommen. Das trifft vor allem fuer das Tulare Lake Basin zu, welches stark von importiertem Wasser des Sacramento-San Joquin Delta abhaengig ist. Diese Ergebnisse werden durch Fernerkundungsdaten brachgelegter landwirtschaftlicher Flaechen bestaetigt. Die Ergebnisse deuten auch an, dass ein breites Band an landwirtschaftlichen Verfahren angewendet werden muss, einschliesslich gemischter Kulturen und Sparmassnahmen.RésuméComme dans de nombreux endroits, les eaux souterraines en Californie (Etats-Unis d’Amérique) constituent la principale ressource d’eau utilisée pour l’agriculture en période de sécheresse; ainsi, la disponibilité en eau souterraine va guider certains changements inévitables dans la gestion de l’eau de l’Etat. Actuellement, les usages agricoles, environnementaux et urbains sont en compétition vis-à-vis de la ressource en eaux souterraines, entraînant de substantiels sur-prélèvements lors des années sèches provoquant des abaissements des niveaux piézométriques avec pour conséquence une augmentation des coûts de pompage et une réduction de la capacité des pompages d’eau souterraine. Dans cette étude, les modèles SWAP (un modèle économique pour la production agricole et l’utilisation de l’eau en Californie) et CV2VISim (le modèle de simulation des eaux souterraines utilisé par le département des ressources en eau de la Californie pour la Vallée Centrale en Californie) sont connectés. Cet article examine les coûts économiques de remplacement des pompages d’eaux souterraines pendant les sécheresses et la perte potentielle de la capacité de pompage lorsque les niveaux piézométriques chutent. Un scénario basé sur la succession de trois années de sécheresse à partir de 2014 montre des niveaux piézométriques bas dans la Vallée Centrale de Californie et une perte de capacité de pompage. Les lieux sans accès à l’eau souterraine et avec une alimentation incertaine par des eaux de surface en période de sécheresse sont les plus vulnérables du point de vue économique en termes de recettes provenant des cultures, de l’emploi et des revenus des ménages. Ceci est particulièrement vrai pour le bassin du Lac de Tulare, qui dépend largement d’une ressource en eau importée du Delta de Sacramento-San Joaquin. Des estimations par télédétection du recul des surfaces agricoles entre 2012 et 2014 confirment ces résultats. Les résultats soulignent également la potentialité d’une approche de gestion de portefeuilles pour l’agriculture, pour laquelle des cultures variées et des pratiques de conservation jouent des rôles essentiels.ResumenEl agua subterránea en California (EE.UU.), como en muchos lugares, es la principal fuente alternativa de agua para la agricultura durante las sequías, por lo que la disponibilidad de agua subterránea impulsa algunos cambios inevitables en la gestión del agua en el estado. Actualmente, los usos agrícolas, ambientales y urbanos compiten por el agua subterránea, lo que resulta en una significativa sobreexplotación en los años secos con la profundización de la capas freática, lo que a su vez aumenta los costos y reduce la capacidad de bombeo del agua subterránea. En este estudio, se vinculan el SWAP (modelo económico para la producción agrícola y el uso del agua en California) y el C2VISim (modelo de agua subterránea del Departamento de Recursos Hídricos para el Valle Central de California). Este artículo analiza los costos económicos del reemplazo del bombeo de agua subterránea durante la sequía y la posible pérdida de la capacidad de bombeo ya que se profundizan los niveles de agua subterránea. Un escenario adicional de tres años continuos de sequía a partir de 2014 muestra los niveles freáticos más profundos en el Valle Central de California y la pérdida de la capacidad de bombeo. Los lugares sin acceso a las aguas subterráneas y con la incertidumbre de la provisión de agua superficial durante la sequía son los más vulnerables económicamente en términos de los ingresos por las cosechas, el empleo y los ingresos familiares. Esto es particularmente cierto para la cuenca del lago Tulare, que depende en gran medida del agua importada del delta Sacramento – San Joaquin. Este hallazgo se confirma con las estimaciones de tierras agrícolas inactivas entre 2012 y 2014 realizadas a través de la teledetección. Los resultados también apuntan a la posibilidad de un enfoque del portfolio para la agricultura, en el cual las prácticas de mezcla de los cultivos y de la conservación tienen papeles importantes.摘要如同在许多地方那样,(美国)加利佛尼亚州的地下水是干旱期间农业主要的可代替的水源,因此,地下水的可用性致使州水管理发生一些必然的变化。目前,农业、环境和城市竞相争用地下水,导致干旱年份大量超采,水位降低,反过来又造成抽水费用增加,地下水抽水能力降低。在本研究中,SWAP(加利佛尼亚州农业生产和水利用经济模型)和C2VISIM(加利佛尼亚州中央谷地水资源地下水模型加利佛尼亚部)连在一起。本文检验了干旱期间抽取替代地下水的经济成本及随着地下水位下降抽水能力的潜在损失。从2014年开始三个另外干旱年的抽水方案显示了加利佛尼亚州中央谷地较低的水位和抽水能力的损失。干旱期间使用不上地下水及地表水供水不确定的地方在作物税收、就业和家庭收入方面最容易受到伤害。这在图莱里湖盆地尤其如此,这个地区主要依赖从Sacramento-San Joaquin三角洲引来的水。2012至2014年闲置农业土地的遥感估算结果确认了这个发现。结果也指明了农业组合方法的潜力,在这个组合方法中农作物搭配种植和保持措施具有重要作用。ResumoComo em muitos lugares, a águas subterrânea na Califórnia (EUA) é a principal alternativa em recursos hídricos para agricultura durante períodos de seca, portanto a disponibilidade de águas subterrâneas trará inevitáveis mudanças na gestão das águas subterrâneas atual. Atualmente, usos agrícolas, ambientais e urbanos, competem por águas subterrâneas, resultando em substancial déficit em anos secos com a redução dos lençóis freáticos, o que aumenta os custos de bombeamento e reduz a capacidade de bombeamento de águas subterrâneas. Neste estudo, SWAP (um modelo econômico de produção agrícola e uso da água na Califórnia) e C2VISim (o modelo de águas subterrâneas do Departamento de Recursos Hídricos da Califórnia para o Vale Central da Califórnia) estão conectados. Este artigo analisa os custos económicos do bombeamento de águas subterrâneas substituição durante a seca e a perdas potenciais de capacidade de bombeamento com a quedo os níveis das águas subterrâneas. Um cenário de três anos adicionais de seca continuada a partir de 2014 mostram lençóis freáticos mais baixos no Vale Central da Califórnia e perda da capacidade de bombeamento. Locais sem acesso à água subterrânea e com fornecimento de água de superfície incerto durante a seca são as mais vulneráveis economicamente em termos de receitas de culturas agrícolas, emprego e renda familiar. Isto é particularmente verdadeiro para a Bacia do Lago Tulare, que depende fortemente de água importados do Delta Sacramento-São Joaquim. Estimativas por sensoriamento remoto de terras agrícolas ociosas entre 2012 e 2014 confirmam esta conclusão. Os resultados também apontam para o potencial de uma abordagem de portfólio para a agricultura, em que as práticas de consórcio de culturas e de conservação têm papéis importantes.

The Variation of Land Surface Phenology From 1982 to 2006 Along the Appalachian Trail

The gradients of the Appalachian Trail (A.T.) in elevations and latitudes provide a megatransect to study environmental variations in the eastern United States. This paper reveals patterns and trends of land surface phenology (LSP) in association with climatic variables within a corridor area along the A.T. We employed time-series data from Global Inventory Modeling and Mapping Studies and the Surface Observation and Gridding System between 1982 and 2006 to extract spatial and temporal variation patterns of LSP metrics and the correlations with meteorological parameters. The derived trends in LSP metrics indicate that the extended length of season mainly resulted from delayed end of season (EOS) across the study area. More significant change occurred in the northern segment than in the southern segment, which reflects latitudinal effects. We analyzed the relationship between LSP and longitude, latitude, elevation, local climatic variables, and large-scale climate oscillations. Delayed start of season in 1989 and advanced EOS in 1988 were observed responding to the La Niña episode during 1988-1989. This paper provides information about the effects of climate and topography on LSP along the Appalachian Mountain ridges.

Relationship between community prevalence of obesity and associated behavioral factors and community rates of influenza-related hospitalizations in the United States

Please cite this paper as: Charland et al.(2012) Relationship between community prevalence of obesity and associated behavioral factors and community rates of influenza‐related hospitalizations in the United States. Influenza and Other Respiratory Viruses DOI: 10.1111/irv.12019.