Using the California Waterfowl Tracker to Assess Proximity of Waterfowl to Commercial Poultry in the Central Valley of California.

Migratory waterfowl are the primary reservoir of avian influenza viruses (AIV), which can be spread to commercial poultry. Surveillance efforts that track the location and abundance of wild waterfowl and link those data to inform assessments of risk and sampling for AIV currently do not exist. To assist surveillance and minimize poultry exposure to AIV, here we explored the utility of Remotely Sensed Moderate Resolution Imaging Spectroradiometer (MODIS) satellite imagery in combination with land-based climate measurements (e.g., temperature and precipitation) to predict waterfowl location and abundance in near real-time in the California Central Valley (CCV), where both wild waterfowl and domestic poultry are densely located. Specifically, remotely collected MODIS and climate data were integrated into a previously developed boosted regression tree (BRT) model to predict and visualize waterfowl distributions across the CCV. Daily model-based predictions are publicly available during the winter as part of the dynamic California Waterfowl Tracker (CWT) web app hosted on the University of California's Cooperative Extension webpage. In this study, we analyzed 52 days of model predictions and produced daily spatiotemporal maps of waterfowl concentrations near the 605 commercial poultry farms in the CCV during January and February of 2019. Exposure of each poultry farm to waterfowl during each day was classified as high, medium, low, or none, depending on the density of waterfowl within 4 km of a farm. Results indicated that farms were at substantially greater risk of exposure in January, when CCV waterfowl populations peak, than in February. For example, during January, 33% (199/605) of the farms were exposed for ≥1 day to high waterfowl density vs. 19% (115/605) of the farms in February. In addition to demonstrating the overall variability of waterfowl location and density, these data demonstrate how remote sensing can be used to better triage AIV surveillance and biosecurity efforts via the utilization of a functional web app-based tool. The ability to leverage remote sensing is an integral advancement toward improving AIV surveillance in waterfowl in close proximity to commercial poultry. Expansion of these types of remote sensing methods, linked to a user-friendly web tool, could be further developed across the continental United States. The BRT model incorporated into the CWT reflects a first attempt to give an accurate representation of waterfowl distribution and density relative to commercial poultry.

Las aves acuáticas migratorias son el principal reservorio de los virus de la influenza aviar (con las siglas en inglés AIV), que pueden transmitirse a la avicultura comercial. Actualmente no existen esfuerzos de vigilancia que rastrean la ubicación y densidad de poblaciones de aves acuáticas silvestres y que vinculen esos datos para informar evaluaciones de riesgo y muestreo para influenza aviar. Para ayudar a la vigilancia y minimizar la exposición de la avicultura comercial a influenza aviar se exploró la utilidad de las imágenes satelitales por espectrorradiómetro de imágenes con resolución moderada (con las siglas en inglés MODIS) y de detección remota en combinación con mediciones climáticas terrestres (por ejemplo, temperatura y precipitación) para predecir la ubicación y densidad de aves acuáticas prácticamente en tiempo real en el Valle Central de California (CCV), donde tanto las aves acuáticas silvestres como las aves domésticas están densamente ubicadas. Específicamente, los datos MODIS y climáticos recopilados de forma remota se integraron en un modelo de árbol de regresión reforzado (BRT) desarrollado previamente para predecir y visualizar la distribución de las aves acuáticas en el Valle Central de California. Las predicciones diarias basadas en modelos están disponibles públicamente durante el invierno como parte de la aplicación dinámica en el del rastreador de aves acuáticas de California (California Waterfowl Tracker, CWT) ubicada en la página de internet de Extensión Cooperativa de la Universidad de California. En este estudio, se analizaron 52 días de predicciones del modelo y se produjeron mapas espaciotemporales diarios con densidades de aves acuáticas cerca de las 605 granjas avícolas comerciales en el Valle Central de California durante enero y febrero de 2019. La exposición de cada granja avícola a las aves acuáticas durante cada día se clasificó como alta, media, baja o nula, dependiendo de la densidad de aves acuáticas dentro de los cuatro kilómetros de una granja. Los resultados indicaron que las granjas tenían un riesgo sustancialmente mayor de exposición en enero, cuando las poblaciones de aves acuáticas en el Valle Central de California alcanzan su punto máximo, en comparación con febrero. Por ejemplo, durante enero, el 33% (199/605) de las granjas estuvieron expuestas durante más de un día a una alta densidad de aves acuáticas frente a un 19% (115/605) de las granjas en febrero. Además de demostrar la variabilidad general de la ubicación y densidad de las aves acuáticas, estos datos demuestran cómo se puede utilizar la teledetección para clasificar mejor los esfuerzos de bioseguridad y vigilancia para la influenza aviar mediante la utilización de una herramienta funcional basada en una aplicación en el internet. La capacidad de aprovechar la teledetección es un avance integral hacia la mejora de la vigilancia para influenza aviar en aves acuáticas en las proximidades de la avicultura comercial. La expansión de estos tipos de métodos de teledetección, vinculados a una herramienta en el internet que es fácil de usar, podría desarrollarse aún más en los Estados Unidos continentales. El modelo de árbol de regresión reforzado incorporado en el sistema de rastreo de aves acuáticas de California refleja un primer intento de brindar una representación precisa de la distribución y densidad de las aves acuáticas en relación con las aves comerciales.

Modeling future climate suitability for the western blacklegged tick, Ixodes pacificus, in California with an emphasis on land access and ownership.

In the western United States, Ixodes pacificus Cooley & Kohls (Acari: Ixodidae) is the primary vector of the agents causing Lyme disease and granulocytic anaplasmosis in humans. The geographic distribution of the tick is associated with climatic variables that include temperature, precipitation, and humidity, and biotic factors such as the spatial distribution of its primary vertebrate hosts. Here, we explore (1) how climate change may alter the geographic distribution of I. pacificus in California, USA, during the 21st century, and (2) the spatial overlap among predicted changes in tick habitat suitability, land access, and ownership. Maps of potential future suitability for I. pacificus were generated by applying climate-based species distribution models to a multi-model ensemble of climate change projections for the Representative Concentration Pathway (RCP) 4.5 (moderate emission) and 8.5 (high emission) scenarios for two future periods: mid-century (2026-2045) and end-of-century (2086-2099). Areas climatically-suitable for I. pacificus are projected to expand by 23% (mid-century RCP 4.5) to 86% (end-of-century RCP 8.5) across California, compared to the historical period (1980-2014), with future estimates of total suitable land area ranging from about 88 to 133 thousand km2, or up to about a third of California. Regions projected to have the largest area increases in suitability by end-of-century are in northwestern California and the south central and southern coastal ranges. Over a third of the future suitable habitat is on lands currently designated as open access (i.e. publicly available), and by 2100, the amount of these lands that are suitable habitat for I. pacificus is projected to more than double under the most extreme emissions scenario (from ~23,000 to >51,000 km2). Of this area, most is federally-owned (>45,000 km2). By the end of the century, 26% of all federal land in the state is predicted to be suitable habitat for I. pacificus. The resulting maps may facilitate regional planning and preparedness by informing public health and vector control decision-makers.

Increases in soil and woody biomass carbon stocks as a result of rangeland riparian restoration.

BACKGROUND: Globally, vegetation in riparian zones is frequently the target of restoration efforts because of its importance in reducing the input of eroded sediment and agricultural nutrient runoff to surface waters. Here we examine the potential of riparian zone restoration to enhance carbon sequestration. We measured soil and woody biomass carbon stocks, as well as soil carbon properties, in a long-term chronosequence of 42 streambank revegetation projects in northern California rangelands, varying in restoration age from 1 to 45 years old. RESULTS: Where revegetation was successful, we found that soil carbon measured to 50 cm depth increased at a rate of 0.87 Mg C ha-1 year-1 on the floodplain and 1.12 Mg C ha-1 year-1 on the upper bank landform. Restored sites also exhibited trends toward increased soil carbon permanence, including an increased C:N ratio and lower fulvic acid: humic acid ratio. Tree and shrub carbon in restored sites was modeled to achieve a 50-year maximum of 187.5 Mg C ha-1 in the channel, 279.3 Mg ha-1 in the floodplain, and 238.66 Mg ha-1 on the upper bank. After 20 years of restoration, the value of this carbon at current per-ton C prices would amount to $US 15,000 per km of restored stream. CONCLUSION: We conclude that revegetating rangeland streambanks for erosion control has a substantial additional benefit of mitigating global climate change, and should be considered in carbon accounting and any associated financial compensation mechanisms.

Cumulative impacts of residential rainwater harvesting on stormwater discharge through a peri-urban drainage network.

Green infrastructure and techniques such as rainwater harvesting have been proposed as a means to reduce stormwater discharge in developed areas prone to floods. We examined the effects of rainwater harvesting on discharge cumulatively through the Perdido River drainage network in the US state of Florida, an area prone to routine rainfall-driven nuisance flooding. We considered scenarios where rainwater is stored in parcels with structures that use septic tanks (where tanks are retired and used as cisterns, volume approximately 5.7 cubic meters); and where a similar volume of water is stored at all developed parcels. To evaluate flow reduction through the drainage network, we modeled effects relative to a flow event with a 1.5-year recurrence interval using a spatial GIS-based cumulative-effects model. Our model predicted that retired septic tanks would reduce discharge by more than 10 percent in only a few areas in the study region, almost exclusively in headwater regions and where density of houses using septic tanks is high. Analysis of all developed parcels storing rainwater indicated that discharge in several areas would be reduced by more than 20 percent. Results indicate a spatially variable potential for rainwater harvesting to reduce routine storm discharge. Spatially continuous hydrologic tools such as the one we use here may be especially useful for managers seeking to prioritize limited resources at locations for maximum benefit.

Modeling Climate Suitability of the Western Blacklegged Tick in California.

Ixodes pacificus Cooley & Kohls (Acari: Ixodidae), the primary vector of Lyme disease spirochetes to humans in the far-western United States, is broadly distributed across Pacific Coast states, but its distribution is not uniform within this large, ecologically diverse region. To identify areas of suitable habitat, we assembled records of locations throughout California where two or more I. pacificus were collected from vegetation from 1980 to 2014. We then employed ensemble species distribution modeling to identify suitable climatic conditions for the tick and restricted the results to land cover classes where these ticks are typically encountered (i.e., forest, grass, scrub-shrub, riparian). Cold-season temperature and rainfall are particularly important abiotic drivers of suitability, explaining between 50 and 99% of the spatial variability across California among models. The likelihood of an area being classified as suitable increases steadily with increasing temperatures >0°C during the coldest quarter of the year, and further increases when precipitation amounts range from 400 to 800 mm during the coldest quarter, indicating that areas in California with relatively warm and wet winters typically are most suitable for I. pacificus. Other consistent predictors of suitability include increasing autumn humidity, temperatures in the warmest month between 23 and 33°C, and low-temperature variability throughout the year. The resultant climatic suitability maps indicate that coastal California, especially the northern coast, and the western Sierra Nevada foothills have the highest probability of I. pacificus presence.