Ecosystem Outcomes
Monitoring Results Highlights
As always, we are deeply grateful for the exceptional work of Jim Coleman and Kate Sindt in conducting, organizing, and synthesizing our ecological monitoring data. Their efforts make it possible for us to engage in analysis and reflection, as we manage our properties across diverse landscapes and evolving conditions.
With so many different management strategies—from compost and seeding to differing grazing pulses, fencing, and fire—it remains challenging to attribute specific ecological changes to individual interventions. However, a consistent insight from nearly a decade of work is that our grazing generally correlates with increased vegetation biodiversity.
This growth pattern has held true across treatments, controls, exclosures, and across the range of properties under SMI management. And while we recognize the natural variability of ecosystems and annual weather impacts, our long-term data continues to reinforce this broad trend.
Sonoma Mountain Institute (Home Ranch)
● Biodiversity increased by 6.5% in grazed treatment plots, compared to a 3.5% increase in exclosures. While this is within the range of annual variation, it mirrors a broader trend we’ve seen over time.
● Historically, grazed areas have shown 120% relatively more vegetation biodiversity than ungrazed controls at SMI.
● Native species cover has increased by 4.5% year-over-year, although this could also be influenced by favorable weather conditions, standard deviation of the data, or a wide range of other factors.
● Perennial species cover is up 10% from 2024, although still below the peak levels observed in 2017.
Triangle G
● Biodiversity saw a 4% increase—a modest change, but directionally positive.
● Native species cover rose by 24%, and perennial cover by 9% in 2025, both promising signs, especially in areas where grazing has been paired with infrastructure upgrades and resting riparian corridors.
● Native species cover rose by 130% and perennial cover by 162% relatively since 2022.
Cayetana
● Perennial species cover rose by 17.5% year over year, and by 40% since 2023. Other Properties
● Across several other properties, we’ve noted encouraging increases in native species cover, although in some areas this is accompanied by declines in perennials. This type of variation underscores the importance of continually analyzing data across time, treatment, and ecological context.
To deepen our analytical and observational processes, the team convened in July for a field-based review of grazing impacts and the year’s star thistle experiments. These collaborative monitoring days in the field are an invaluable tool for interpreting trends, refining our management strategies, and strengthening the shared understanding and trust that sustain our regional grazing community.
TG Star Thistle Treatment Review and Analysis
As we all know, Triangle G has been characterized by a nearly ubiquitous presence of Yellow Star Thistle (YST) since the start of our management efforts. Over the past three years, SMI has implemented a wide range of treatments to determine whether a shift in species composition could be encouraged, particularly in the most infested area—Benny’s Ranch (ACC1). Initial site-level monitoring suggested that star thistle cover in these areas ranged from 70% to 85%. In early 2023, we launched a series of experimental treatments involving high-density cattle grazing combined with alfalfa feeding, followed by a cross-sectional vegetation assessment of 13 monitoring points in summer 2025 to try to compare as best as we could the effectiveness of treatments.
Treatments Overview
Cattle/Feeding Treatments: Conducted in February 2023, spring 2023, and again in June 2024, with between 1–3 tons of feed per acre. Some plots were also seeded with rye, Festulium, and livestock mixes in November 2024.
Goat Grazing Treatments: Took place in late summer across 2023, 2024, and 2025. Control Plots: Maintained without intervention for baseline comparison.
Key Findings
In plots treated with cattle and hay, YST cover decreased from ~75% to 45%, representing a relative reduction of ~30%. Repeating the grazing treatments two or three times did not always produce marginally greater reductions in YST cover. Seeding appeared to correlate with an additional 15–20% reduction in YST compared to adjacent non-seeded areas with similar treatment history—an encouraging trend, though causality cannot be confirmed.
The goat grazing plots showed the strongest effect. One goat-treated plot dropped from an estimated 75% to 35% YST cover. A second goat-grazed plot inside Benny’s camp dropped all the way to 3% YST cover, though it lacked a formal control and had other treatments involved historically in addition to the goat grazing.
Conclusions
● Cattle + hay feeding treatments were effective, reducing YST cover by approximately 32%.
● Seeding in conjunction with feeding may amplify impact, though more data is needed.
● Goat grazing emerged as the most impactful strategy, both in terms of consistency and scale of suppression.