SCIENCE AT TOMKAT RANCH Sept. 2021

Last Updated: Sept 30, 2021 by Chelsea Carey, Point Blue Conservation Science

ECOLOGICAL MONITORING WITH POINT BLUE CONSERVATION SCIENCE

Rangeland Monitoring Network

The ranch is part of Point Blue Conservation Science’s Rangeland Monitoring Network (RMN) measuring ecological function: water infiltration, soil bulk density, soil organic carbon, plant abundance and diversity, and bird abundance and diversity.  RMN includes a monitoring handbook with methods, web-based data entry tools, and online data storage. RMN is in its seventh year and is monitoring approximately 100  ranches across 25 counties in California. 

In addition to the RMN metrics, TomKat Ranch monitors soil nutrients and microbial communities. 

Stream Monitoring and Weather Station Data

With assistance from Trout Unlimited, the ranch maintains a stream gauge on Honsinger Creek to monitor water temperature, streamflow, and stage. Additionally, the ranch maintains a weather station.

All of these monitoring data are available on our interactive Ranch Data Project web page.

Water Quality Monitoring

TomKat Ranch has initiated a water quality monitoring program with Point Blue Conservation Science modeled after protocols used by the San Mateo County Resource Conservation District. Two years of data have been collected on sediment, metal, and bacterial loads detected as Honsinger Creek enters and exits TomKat Ranch. These data are being used to build a more robust water monitoring design.

Bird Banding

In addition to conducting ranch-wide point count surveys, Point Blue monitors bird communities at TomKat Ranch through annual bird banding along Honsinger Creek. 

EXPERIMENTS AND TRIALS
AT TOMKAT RANCH

Bale Grazing Trials

In 2021, Point Blue and TomKat Ranch staff began designing a trial to measure how bale grazing affects pasture plants and soil health.

Soil Health Trials

Objectives

1. Observe the effects of different management approaches on fungal/bacterial ratios, forage quality, and forage production. The trials include Earthfort’s microbial inoculant and humic acid; range planting; and a mixture of soil additives and amendments.

Status

1. We are in the fourth year of sampling for some of the treatments, and the third year of sampling for others. We have written a manuscript on the Earthfort biostimulant project for publication, and are in the process of receiving final reviews prior to submission at the Frontiers of Sustainable Food Systems Journal.

Take-away (subject to change as new data becomes available)

1. We are seeing a boost in plant production and some metrics of forage quality with the application of biostimulants (microbial inoculants and humic acids). Soil microorganisms have not responded in a similar way to these biostimulants,  but we will continue to track this over time. There has been very little response from the system to other soil additives and amendments and the pasture seeding.

Influence of Compost Applications on Soil Microbial Communities and Perennial Grass Success (mesocosm experiment)

Objectives

1. Determine the relative effects of soil origin (type), compost applications, and plant-soil feedbacks on productivity and success of perennial grasses.
2. Identify the mechanisms (microbial community, soil nutrients) by which these effects are generated.
3. Learn about how this system can be explored through experiments.

Status

1. Results have been summarized.

Take-Aways

1. Initial growth of Stipa pulchra did not differ by treatment or soil origin. Compost additions minimized nitrate concentrations in soils from the west side of the ranch, but in general nutrient supply was affected more by soil origin (west versus east side of the ranch) than compost additions in this experiment. For example, calcium supply was much greater in soils from the east side than the west side.

Rangeland Compost Application (Natural Resources Conservation Service and East Stanislaus Resource Conservation District)

Objectives

1. Participate in a statewide program to measure the effects of compost applications to soil carbon sequestration, vegetation diversity/health, and net primary production on a variety of rangelands.

Status

1. Data from this trial contributed to a 2018 report on carbon sequestration and greenhouse gas mitigation potential of composting and soil amendments on California rangelands, which was part of California’s Fourth Climate Change Assessment

Take-away (subject to change as new data becomes available)

1. One year after compost application, the treated and control plots at TomKat Ranch had similar soil organic carbon (%) levels, both around 2.8%. Across all of the 14 participating rangeland sites, soil carbon stocks (Mg C ha-1) were elevated in sites receiving compost, but this appeared to be driven by changes in bulk density not in carbon concentration (% soil organic carbon).

Native Grass Strip Seeding Trial (University of California, Davis)

Objectives

1. Test the feasibility and effectiveness of planting native grasses in strips to reduce planting costs. 

Status

1. Based on this work, researchers leading the project have written a guide entitled, Native Grassland Restoration for Resilient Coastal Ecosystems, which can be found here. 

Take-away

1. The feasibility of the strip seeding method may be challenged by the limited availability of the appropriate no-till drill in California. 
2. The initial establishment of perennial grasses with this method varied widely across the three participating ranches. For example, Rush Ranch saw good establishment, while Sears Point had poor establishment. So, in some places strip-seeding may be a valuable tool for perennial grassland restoration.

ADDITIONAL PROJECTS

Well Recharge Monitoring (Wellntel)

Using technology from Wellntel, the ranch uses sonar to track real-time levels and recharge rate of wells.  This information helps understand seasonal fluctuations in groundwater availability and plan water usage more effectively.  It may also provide information to help better understand if land management practices are affecting availability and/or recharge of groundwater.

Savory Ecological Verification Program

TomKat Ranch is participating in Savory’s Ecological Outcomes Verification program that is part of their Land to Market certification. EOV is a protocol for monitoring land health that measures and identifies trends in indicators of ecosystem function, including soil health, biodiversity, and water dynamics in order to support holistic management. 

Remote Sensing of Rangeland Condition

The ranch helped to test tools from Ucross High Plains Stewardship Initiative to measure landscape-level changes in biomass production and bare ground. Their Google Earth Engine-based tool, currently called Change Vector Analysis (CVA), uses Landsat imagery to compare changes over time in cumulative annual biomass production and bare ground of a given property.

Quick Carbon

TomKat Ranch and Point Blue helped to test Quick Carbon technology across California’s rangelands. Created and led by scientists from the Yale School of Forestry & Environmental Studies, Quick Carbon is endeavoring to create an open-source technique based on low-cost spectrometers and machine-learning algorithms to rapidly measure soil carbon in the field. 

Total Impact Measurement and Management (TIMM) Analysis

The TIMM study was conducted using a framework developed by PricewaterhouseCoopers (PwC) with the intention quantifying and valuing the net societal value generated by regenerative ranching across a wide range of impact areas including animal welfare, net greenhouse gas emissions, profits, wages, water pollution, water use, soil health, sediment, and habitat.  The study uses primary data from TomKat Ranch and peer-reviewed secondary data from scientific literature and compares the estimated net societal value generated by TomKat Ranch’s beef production to a model of standard beef in California in similar weather and geographic conditions.

Soil Health and Water Infiltration Report (Union of Concerned Scientists)

The TomKat Foundation provided funding for the Union of Concerned Scientists to explore the scientifically-verified ways that key US agricultural sectors can contribute to efforts to sequester carbon and reduce net US climate emissions while improving broader ecosystems and sustainability efforts.  One product of this work has been the report Turning Soils into Sponges: How Farmers Can Fight Floods and Droughts (2017) that explored the ability for agricultural practices to increase the health of soils and their ability to safely and productively absorb and hold water.

The Science and Practice of Soil Organic Carbon Measurement

TomKat supported researchers from the University of Wisconsin to organize two workshops in 2016 and 2017, and subsequently prepare a set of 11 white papers on the topic of soil organic carbon measurement with the purpose of building the needed science for improved management of soil organic carbon for soil health and climate change mitigation. One paper, co-authored by Point Blue’s Libby Porzig and Nat Seavy and 20 other scientists, was recently published in the  journal, Carbon Management (see below).  

Modeling to Promote Climate-Smart Conservation on Working Lands

TomKat supported a Point Blue-led workshop in 2019 to better understand the state of carbon modeling efforts and how empirical data collection projects, like those led by TomKat and Point Blue, can advance these efforts on working lands to more effectively promote climate-smart conservation and regenerative agriculture. The group discussed ways that our data can help support platforms like COMET-Planner and CALAND, which inform California’s 2030 Natural and Working Lands Climate Change Implementation Plan. 

Nerd Night

TomKat Ranch and Point Blue collaborate to host an annual event aimed at sharing scientific findings and activities to support regional regenerative stewardship, and to celebrate those who participate in the regenerative journey with us. Themes have included applying ecological data to management, stewarding life belowground, and building resilient rangelands by stewarding California oaks. 

Fire Ecology Virtual Speaker Series

TomKat supported a virtual speaker series in 2021 focused on covering emerging research and programs on wildfire and prescribed burns that are relevant to the ecology and management of California’s rangelands. Topics included wildfire risk mitigation, fire as a tool for ecological stewardship, and biodiversity responses to fire. Recorded talks can be found at this link here.

PEER-REVIEWED PUBLICATIONS

Accepted

Ahlering, M., Kazanski, C., Lendrum, P.E., … Porzig, E., Rizzo, D., Spiegal, S., & C. Wilson. Accepted. A synthesis of ranch-level sustainability indicators for land managers and to communicate across the beef supply chain. Rangeland Ecology & Management. 

Summary: Great clarity on which indicators are most effective for assessing sustainable grazing management will help to support growing interest in monitoring among ranchers and throughout the supply chain. This review synthesized information from existing rangeland monitoring guidance and programs to identify 20 commonly used core indicators that could guide future use and selection by ranchers, companies, or government programs. 

Published

Carey, C.J., Weverka, J., DiGaudio, R., Gardali, T., and E.L. Porzig. 2020. Exploring variability in rangeland soil organic carbon stocks across California (USA) using a voluntary monitoring network. Geoderma Regional 22: ee00304. 

Summary: A necessary step toward appropriately and effectively stewarding soil carbon is understanding baseline variability in carbon stocks and identifying how that variability relates to factors such as climate, soil texture, and topography. We leveraged our Rangeland Monitoring Network to explore how soil carbon varies with geographic distance, climate, vegetation, soil type, and topography within and across three regions of California. As expected based on climate, the Central Coast harbored the largest soil carbon stocks. However, within a region, there was large variability in soil carbon, and much of that variability was unexplained by the predictor variables included. Some of the unexplained variation is likely due to past and current land use, and this suggests that there is potential to rebuild soil carbon through management.

Carey, C.J., Gravuer, K., Osleger, D. et al. 2020. Supporting evidence varies for management practices that seek to improve soil properties and forage production in California. California Agriculture 74: 101-111. 

Summary: There is a growing expectation for rangeland management practices to promote co-benefits throughout California such as forage production, plant diversity, and climate mitigation. In this paper, we leveraged published literature derived exclusively from California to explore how prescribed grazing, silvopasture, compost amendments, and riparian restoration influence a suite of soil and plant-related metrics across the state. Silvopasture (i.e., the presence of oaks) had the largest effects on soil properties of any management practice assessed, with SOC, microbial biomass, and other measures of soil fertility elevated beneath oak canopies. We found varying levels of evidence to support relationships among management practices and response metrics, and use this information derived from our synthesis to highlight priority areas for future research. 

Humple, D.L., Cormier, R.L., Richardson, T.W., et al. 2020. Migration tracking reveals geographic variation in the vulnerability of a Nearctic-Neotropical migrant bird. Scientific Reports 10: 1-7.

Summary: One important step toward identifying and prioritizing management actions to conserve wildlife populations is determining how vulnerable they are to environmental changes. For migratory species, which are affected by conditions in more than one location, assessing vulnerability (amount of risk) also must consider where they travel throughout their annual life cycle. Recent advances in tracking technology now allow us to identify these migratory connections and explore the links between population declines and habitat change in both breeding and non- breeding regions. Point Blue collaborated with the Tahoe Institute for Natural Science to deploy tracking tags on Swainson’s Thrushes in the San Francisco Bay Area (including TomKat Ranch) and the Cascade-Sierra. The populations studied each migrated different distances and predominantly to these different regions: coastal birds to western Mexico, Lassen birds to Central America, and Tahoe birds to northwestern South America. The longer migration distance and greater recent forest loss suggest greater current vulnerability of the rarer Cascade-Sierra birds to environmental change. Our results demonstrate that quantifying migration distances and destinations among neighboring breeding populations can identify dramatically different vulnerabilities that need to be considered in conservation planning, which must also be integrated internationally. Summary adapted from Point Blue’s publication brief.

Bradford, M.A., Carey, C.J., Gennet, S., et al. 2019. Soil carbon science for policy and practice. Nature Sustainability. 

Summary: Soil-based initiatives to mitigate climate change and restore soil fertility both rely on rebuilding soil organic carbon. In this paper, we argue that there is scientific consensus on the need to rebuild soil carbon for sustainable agricultural land stewardship, and suggest that controversy about the role soils might play in climate change mitigation is eroding scientific credibility in the related but distinct effort to protect and restore soils more generally by rebuilding soil carbon. We synthesize the science supporting actions to rebuild soil carbon for improved ecosystem functioning (e.g., fertility, water capture), highlight areas of uncertainty, and suggest how to move forward to promote confidence in the scientific credibility of carbon-centric soil health initiatives.

Paustian, K. Collier, S., Baldock, J., et al. 2019. Quantifying carbon for agricultural management: from the current status toward a global soil information system. Carbon Management 1758-3012.

Summary:  Any effort to value improvements in the performance of agricultural soils through enhanced levels of SOC will require feasible, credible and creditable assessment of SOC, which are governed by dynamic and complex soil processes and properties. This paper evaluates currently accepted methods of quantifying and forecasting SOC that, when augmented and pulled together, could provide the basis for a new global soil information system. 

Porzig, E.L., Seavy, N.E., Owens, B.E., and T. Gardali. 2018. Field evaluation of a simple infiltration test and its relationship with bulk density and soil organic carbon in California rangelands. Journal of Soil and Water Conservation 73: 200-206.

Summary: Water infiltration is commonly recommended as an indicator of soil health and water cycling on rangelands. This paper investigates the utility of a two-trial single-ring infiltration test to act as an indicator of bulk density and carbon concentration using Rangeland Monitoring Network data.  We found that, yes, water infiltration is a useful, but imprecise, indicator of soil bulk density and carbon concentration and so may be useful to land managers who are interested in, but unable to measure, these other important but harder-to-measure properties. 

De Longe, M. and A. Basche. 2018. Managing grazing lands to improve soils and promote climate change adaptation and mitigation: a global synthesis. Renewable Agriculture and Food Systems 33: 267-278.

Summary: Leveraging grasslands for climate change mitigation and adaptation requires a better understanding of how ranchers can improve management and related outcomes. This paper quantitatively synthesizes the literature to determine how soil water infiltration rates and carbon concentrations vary with grazing strategies. Results suggest that grazing management can be altered to improve soil water infiltration rates, with possible benefits for soil carbon as well. This paper also highlights a shortage of well-replicated and detailed experiments comparing grazing management systems, spotlighting the need for additional research in this area. 

Henneman, C., Seavy, N.E., Porzig, E.L., Reiter, M.E., and T. Gardali. 2014. Restoring native perennial grasses by changing grazing practices in Central Coastal California.  Ecological Restoration 32: 352-354.

Summary: In 2011, TomKat Ranch switched from continuous to planned grazing. After just three years,  perennial grass occurrence increased by 72%. This increase in perennial grass occurrence means that the ranch’s grazing management allowed the opportunity for these desirable plants to spread. 

In Preparation

Carey, C.J., Strohm, H., Smith, F., and M. Biaggi. In prep. Applying biostimulants boosts forage productivity without affecting soil biotic and abiotic parameters on a Central Coast California rangeland. Frontiers in Sustainable Food Systems.

DiGaudio, R., Preston, M., Eyestone, B., Allen, H., and E.L. Porzig. In prep. Comparing bird densities in California oak woodlands and grasslands to known population targets for conservation.

OTHER PRODUCTS

Guides

Carey, C.J., and M. Preston. 2019. Life belowground on the range: An introduction to the soil communities that support our rangelands. 

Preston, M. 2017. Guide to the Pasture Plants of San Mateo County.

Henneman, C. Seavy, N., Gardali, T., et al. 2013. Common species of the working lands of Coastal San Mateo County: A Wildlife Checklist. 

White Papers and Reports

Foster, E. and C.J. Carey. 2021. A Scoping Paper for Developing Rangeland Carbon Monitoring Protocols. 

Veloz, S. Elliot, N., Carey, C.J., and E.L. Porzig. 2021. Pescadero Soil Carbon Mapping Technical Report. Point Blue Report. 

Carey, C.J., and N.E. Seavy. 2018. Methane Emission from Livestock. Point Blue Issue Brief, Ver 1.

Carey, C.J. 2018. Soil Health on Rangelands. Point Blue Report.

Odom, L., Carey, C.J., et al. 2018. Assessing and Managing Soil Health on Rangelands and Pasture Lands. Product of workshop at Noble Institute in Ardmore, Oklahoma.

Media

In-field soil health assessment YouTube videos to support Regenerative Organic Certification.

Planning Documents

San Mateo RCD. October 2017. TomKat Ranch Carbon Farm Plan. San Mateo Resource Conservation District, Half Moon Bay, California.

Point Blue Conservation Science and TomKat Ranch Educational Foundation. 2014. Scenario Planning for Climate Change at TomKat Ranch: Final Report. Point Blue Conservation Science and TomKat Ranch Educational Foundation, Petaluma, California. 

Henneman, C., T. Gardali and N. E. Seavy. 2012. A landscape conservation plan for TomKat Ranch. Version 1.1. Report to the TomKat Ranch. PRBO Conservation Science, Petaluma, California. 

SELECT PRESENTATIONS FROM WORKSHOPS AND CONFERENCES (NOT AN EXHAUSTIVE LIST)

Carey, C.J. Soil health stewardship of California’s rangelands: Conducting science to inform action. Ecological Society of America, GroundBreaking Women in Soil Ecology Panel. July 2021.

Carey, C.J. The science underpinning regenerative agriculture. Regenerative Agriculture Groundwork Group. July 2020. 

Carey, C.J. Life belowground: An introduction to the soil communities that support California’s rangelands. Elkhorn Slough Healthy Soils Demonstration Day. January 2020. 

Carey, C.J. Using science to inform stewardship of California’s rangelands. University of California Merced, December 2019. 

Porzig, E.L., Carey, C.J., and W. Gilgert. The Rangeland Monitoring Network: Connecting Soil Health to Biodiversity and Stewardship on California’s Rangelands. Soil Health Institute Annual Meeting, Sacramento, CA, July 2019.

Carey, C.J., Strohm, H., Smith, F., and M. Biaggi. Assessing the effects of a microbial inoculant and biostimulant on rangeland soil microbial and plant community dynamics in California. Soil Health Institute Annual Meeting, Sacramento, CA, July 2019.

Carey, C.J., Gravuer, K., Osleger, D., Gennet, S., and S.A. Wood. Using meta-analysis to understand the effects of rangeland management practices on soil properties and plant-related outcomes in California. Soil Ecology Society Meeting, Toledo, OH, June 2019.

Preston, M., Allen, H., DiGaudio, R., Eyestone, B., and E.L. Porzig. California’s rangelands matter for birds. Western Section of TWS, Tenaya Lodge, Yosemite, February 2019.

Carey, C.J., Porzig, E.L., et al. The connection between grazing and soil health: what do we know and what are we learning? Central Coast Rangeland Coalition Meeting, Swanton Pacific Ranch, November 2018. 

Porzig, E.L., Carey, C.J., Seavy, N.E., et al. Plant community composition and variation in soil organic carbon in California rangelands. Society for Range Management Meeting, Sparks, NV, January 2018.

Carey, C.J. State of the Science Panel: Assessing and managing soil health on rangelands and pasturelands meeting. Noble Research Institute, Ardmore, OK, November 2017.

Carey, C.J., D. Millar, M. Preston, et al. Monitoring biotic and abiotic soil parameters to inform regenerative grazing practices across California’s rangelands. Soil Ecological Society Meeting, Fort Collins, CO. June 2017.

Porzig, E., Carey, C.J., and N.E. Seavy. Plant community composition and variation in soil organic carbon in California rangelands. Soil Ecological Society Meeting, Fort Collins, CO, June 2017.

Garbach, K,  and EL Porzig Rangeland Watershed Initiative: Exploring Partnerships to Enhance Ecosystem Services for Rural and Urban Communities. CARCD Conference, November 2016.