Integrating microbial ecology into ecosystem models: challenges and priorities

Microbial communities can potentially mediate feedbacks between global change and ecosystem function, owing to their sensitivity to environmental change and their control over critical biogeochemical processes. Numerous ecosystem models have been developed to predict global change effects, but most do not consider microbial mechanisms in detail. In this idea paper, we examine the extent to which incorporation of microbial ecology into ecosystem models improves predictions of carbon (C) dynamics under warming, changes in precipitation regime, and anthropogenic nitrogen (N) enrichment. We focus on three cases in which this approach might be especially valuable: temporal dynamics in microbial responses to environmental change, variation in ecological function within microbial communities, and N effects on microbial activity. Four microbially-based models have addressed these scenarios. In each case, predictions of the microbial-based models differ—sometimes substantially—from comparable conventional models. However, validation and parameterization of model performance is challenging. We recommend that the development of microbial-based models must occur in conjunction with the development of theoretical frameworks that predict the temporal responses of microbial communities, the phylogenetic distribution of microbial functions, and the response of microbes to N enrichment

Review of research to inform California's climate scoping plan: Agriculture and working lands

Agriculture in California contributes 8% of the state's greenhouse gas (GHG) emissions. To inform the state's policy and program strategy to meet climate targets, we review recent research on practices that can reduce emissions, sequester carbon and provide other co-benefits to producers and the environment across agriculture and rangeland systems. Importantly, the research reviewed here was conducted in California and addresses practices in our specific agricultural, socioeconomic and biophysical environment. Farmland conversion and the dairy and intensive livestock sector are the largest contributors to GHG emissions and offer the greatest opportunities for avoided emissions. We also identify a range of other opportunities including soil and nutrient management, integrated and diversified farming systems, rangeland management, and biomass-based energy generation. Additional research to replicate and quantify the emissions reduction or carbon sequestration potential of these practices will strengthen the evidence base for California climate policy

Key ecological principles to guide adaptive management of grassland weeds under variable conditions 

Managing Weeds in Grasslands and Rangelands (2021) online event recording

Animals and fungi can affect goatgrass establishment

The establishment of barb goatgrass is greatly affected by its interactions with other species in California grassland. For example, goatgrass establishment is enhanced by a fungus, Ulocladium atrum. This fungus is visible as black lesions on the surface of the seedhead; it helps break down the tough, woody seedhead surrounding goatgrass seeds. This speeds up germination and leads to a 65% increase in goatgrass bio-mass at the end of the growing season

Plant species provide vital ecosystem functions for sustainable agriculture, rangeland management and restoration

Plants respond to and change their environments, actively altering factors such as soil stability, nutrient and water availability, and the distribution of pests and beneficial organisms. By identifying the functions associated with different species and the effects they have on their ecosystems, managers can use plants as tools in agriculture, range management and restoration, since they will be able to choose plants more effectively and anticipate unintended consequences of vegetation changes. Because cover crops have been used in agricultural settings for years, much is known about their functioning and response to environmental conditions and management practices. Much less is known about plants in natural systems, yet this information can be critical to range management and restoration. We compare what is known about grassland plant functions in California by reviewing the extensive research that has been undertaken at the UC Hopland Research and Extension Center

Plant species provide vital ecosystem functions for sustainable agriculture, rangeland management and restoration

Plants respond to and change their environments, actively altering factors such as soil stability, nutrient and water availability, and the distribution of pests and beneficial organisms. By identifying the functions associated with different species and the effects they have on their ecosystems, managers can use plants as tools in agriculture, range management and restoration, since they will be able to choose plants more effectively and anticipate unintended consequences of vegetation changes. Because cover crops have been used in agricultural settings for years, much is known about their functioning and response to environmental conditions and management practices. Much less is known about plants in natural systems, yet this information can be critical to range management and restoration. We compare what is known about grassland plant functions in California by reviewing the extensive research that has been undertaken at the UC Hopland Research and Extension Center

Animals and fungi can affect goatgrass establishment

The establishment of barb goatgrass is greatly affected by its interactions with other species in California grassland. For example, goatgrass establishment is enhanced by a fungus, Ulocladium atrum. This fungus is visible as black lesions on the surface of the seedhead; it helps break down the tough, woody seedhead surrounding goatgrass seeds. This speeds up germination and leads to a 65% increase in goatgrass bio-mass at the end of the growing season