Location: Sustainable Agricultural Water Systems Research
2022 Annual Report
Objectives
The USDA California Climate Hub program will enable climate-informed decision-making through the successful development of science-based, region-specific syntheses, information products, decision support tools and technologies for agricultural, forestry and natural resource managers, and where possible provide assistance to enhance adoption and implementation of the same. The aforementioned will be accomplished through investments via three primary pathways: (i) data and information syntheses; (ii) tool and technology development, curation and implementation support; and (iii) convening to support technical assistance, training and information exchange. The work will be conducted as the California USDA Climate Change Hub (CACH) and will be coordinated with ARS, NRCS, USFS broadly and locally, and other USDA and non-USDA organizations in accordance with guidance found in the USDA Climate Change Hubs Charter, and Terms of Reference. The focus of these activities will be the regions natural and working lands, inclusive of all farms, ranches, forests and other production and natural systems however with special attention to agro-climate applications in specialty crop and forestry contexts.
Objective 1: Enable climate-smart decision-making by developing science-based, region-specific information, tools and technologies for agricultural and natural resource managers, and provide assistance where possible to enhance adoption and implementation of the same.
Objective 2: Expand and enhance each Hub’s research and communication capacity and ensure integration of ARS research outcomes from across the region into Hub outreach assets.
Approach
The CACH program will co-develop and produce science-based syntheses to elucidate expected climate impacts, stressors and/or disturbances using largely readily available climate and weather data. These outputs will lead to products to report and communication climate-linked impacts to natural and working land interests and assets that are place- and/or resource-based including climate scenarios (forecasts) and vulnerability assessments. Efforts will also include the translation of climate and weather data to communicate current conditions, extreme events and lookout forecasts. The program will also support and/or co-develop products resulting from novel frameworks, stakeholder need (or barrier) assessments, technologies or techniques leading to the advancement of practices founded in climate adaptation and mitigation science. Products may include but are not limited to peer reviewed, government, trade or technical assistance papers, reports, bulletins or articles.
Investments and products that result from synthesized information sets or tools leading to an improved interpretation of and/or new understanding of changing natural and working land management systems in context of climate change in the form of decision support tools, toolkits, dashboards, factsheets, agriculture or forestry alerts will remain a core program focus. Generally speaking, this can include outputs akin to agro-climate or other climate informed agriculture or forestry decision support systems or web-based applications. These products will provide a better understanding of climate change information (literacy), facilitating improved management practices to both adapt and mitigate the effects associated with climate change.
Designing, developing and organizing opportunities for information exchange, content appropriate/specific conferences, workshops, symposia, dialogs, field days, site demonstrations, trainings through convening of focused groups of managers, practitioners, scientists, technical assistance provider’s etc. Additionally, we will regularly produce, develop and disseminate information products in the form of newsletters, blogs, etc. using a variety of media including social, trade and popular outlets. CACH staff will contribute and serve on advisory and steering committees, give lectures, webinars, presentations to audiences that support the broader mission and function of the USDA Climate Hub program and needs and requests of stakeholders. We will also continually evaluate (assess) and communicate the needs of producers and managers to the science community as well as sharing science-based knowledge and applications to those that can act on that information.
Progress Report
In support of Element I of Objective 1, research was conducted to evaluate a suite of energy-based agroclimate metrics and calculated changes over the two most recent normal periods (1981–2010 and 1991–2020), focusing on specialty crop production regions in California. While most metrics showed small changes between the two periods, during the 1991–2020 period, the last spring freeze occurred approximately five days earlier as compared to the 1981–2010 period, contributing to an over six day longer frost-free period in the Sacramento and Salinas Valleys. Likewise, an additional 6.4 tropical nights (Tn > 20° C) occurred in the Coachella Valley during the 1991–2020 period. A complementary trend analysis of the agroclimate metrics over the 1981–2020 period showed significant increases in growing degree days across all agricultural regions, while significant increases in heat exposure were found for the Salinas and Imperial Valleys and over the Central Coast region. Observed changes in agroclimate metrics were largely consistent with broader global warming trends. Quantifying the shifts in these agroclimate metrics between the two most recent 30-year normal periods and the accompanying 40-year trends provides context for understanding and communicating around changing climatic baselines and underscores the need for adaptation to meet the challenge that climate change poses to agriculture, both in the future and in the present.
In support of Element II of Objective 1, advancements were made that have resulted in a final draft synthesis of climate adaptation strategies, approaches, and practices for specialty production systems in California. A handbook for small parcel forest landowners in the Sierra Nevada/Cascade region has been published by the United States Forest Service to assist private forest landowners develop a site assessment and determine appropriate management strategy for forest parcel owners to increase fire resilience or adaptive capacity for climate change. Additional research is being conducted using climate models and projected plant water stress to assess which California counties are expected to be most impacted by future climate change impacts. The counties that have the most land area classified as rangelands and also counties that have the highest beef production are highlighted to evaluate impacts to both rangeland-based ecosystem services, like biodiversity and the beef production industry. Approaches for land and range managers to adapt to a changing future to buffer potential effects are also considered. Advancements have been made toward the web-based compendium of climate-based decision support tools for agricultural production called CalAgroClimate. A prototype tool is in beta testing phase for predicting pests and disease by crop type x location and growing degree days by crop type x location.
In support of Element III of Objective 1, eight roundtable dialog (listening/exchange) sessions were conducted focused on assessing opportunities and barriers leading to the advancement of regionally appropriate nature-based solutions on natural and working lands for California. The information gained from those events has been synthesized in a draft summary report. We developed and conducted two workshops for the United States Forest Service (USFS) focused on advancing climate science literacy and climate adaptation science understanding for mid-level leadership. Two climate adaptation planning workshops were co-led for two individual USFS districts in Region 5 and one such workshop for curators and managers of national and international public gardens. A workshop was co-hosted focused on reforestation in context of large fires and climate change in the Southern Sierra Nevada ecosystem.
Accomplishments
1. Observed changes in agroclimate metrics relevant for specialty crop production in California. Climate normals are calculated every 10 years, and the most recent normals were calculated in 2021 and cover the years 1991-2020. For agricultural producers there are additional measures of climate, known as agroclimate metrics, that give a more meaningful picture of climate as it relates to growing crops. Understanding how these agroclimate normals change over time can be important for farm management decisions. ARS researchers in Davis, California, calculated 12 agroclimate metrics for the two most recent normal periods (1981-2010 and 1991-2020) and determined the change between these two periods. The results showed that heat exposure is more frequent and that growing seasons are longer in the new normal period (1991-2020) as compared to the previous normal period (1981-2010). Similarly, the 40-year trends in agroclimate metrics were consistent with what are expected given global warming. The changes in agroclimate normals and the 40-year trends provide observational evidence of a changing climate. These changes underscore the need for adaptation in order to maintain agricultural production.
2. Forest management handbook for small-parcel landowners in the Sierra Nevada and Southern Cascade Range. Contemporary forests in the Sierra Nevada and southern Cascades are stressed by a number of factors that put them at risk. High severity wildfire, drought stress, insect outbreaks, disease, and a backdrop of changing climate all pose a threat to the persistence of these forests. A significant portion of these forests are owned and managed by nonindustrial private landowners who typically own small parcels (e.g., 10 to 50 acres). ARS scientists at Davis, California, prepared a guidebook structured in a step-by-step manor that walks the small parcel forest landowner through the process of objective-setting for their property, site inventory, a basic risk assessment, potential management options and an outline of available resources. The user-friendly guidebook, which is informed by scientific information, enables decision-making for private forest landowners.
Review Publications
Parker, L.E., Zhang, N., Abatzoglou, J.T., Ostoja, S.M., Pathak, T.B. 2022. Observed changes in agroclimate metrics relevant for specialty crop production in California. Agronomy. 12(1). Article 205. https://doi.org/10.3390/agronomy12010205.
Maier, P.A., Vandergast, A.G., Ostoja, S.M., Aguilar, A., Bohonak, A.J. 2022. Gene pool boundaries for the Yosemite Toad (Anaxyrus canorus) reveal asymmetrical migration within meadow neighborhoods. Frontiers in Conservation Science. 3. Article 851676. https://doi.org/10.3389/fcosc.2022.851676.
