Carbon is the energy currency of most biological systems, including agricultural ecosystems. All agricultural production originates from the process of plant photosynthesis, which uses sunshine to combine carbon dioxide (CO2) from the air with water and minerals from the soil to produce plant material, both above and below ground.
Agriculture is the ONE sector that can
transform from a net emitter of CO2
to a net sequestered of CO2
There is no other human-managed realm with this potential. Common agricultural practices, including driving a tractor, tilling the soil, grazing, result in the return of C02 to the air. However, all farming is “carbon farming” because all agricultural production depends upon plant photosynthesis to move carbon dioxide out of the atmosphere and into the plant, where it is transformed into agricultural projects, whether food, flora, fuel or fiber.
Agriculture only contributes 9% of the carbon dioxide emissions in the US.1 Agriculture, particularly grassland/rangelands, have a great potential to function as a sponge for carbon dioxide from our atmosphere. The maximum capacity of soil to store organic carbon is determined by soil type (% clay). However, management practices, implemented to maximize plant growth and minimize losses of organic carbon from soil, will result in greatest organic carbon storage in soil. Keeping working lands “working” can result in carbon stored long term (decades to centuries or more) beneficially in soils in a process called soil carbon sequestration; long-term carbon storage (decades to centuries or more) in soils.
Keeping working lands “working” can result in
carbon stored long term
Rangelands: There are 23 million hectares of rangeland in California alone, and it is the largest land type on our planet today. Management of rangelands, through grazing, can lead to increased forage production, longer growing season and a potential conversion to a perennial system. Implementation of practices can meet both ranch goals while increasing the carbon sequestration on rangelands. Grazing stimulates plant growth through a variety of mechanisms, resulting in increased carbon capture by the grazed ecosystem. The potential to increase the amount of carbon held in rangeland ecosystems or to minimize losses of existing carbon offer landowners an opportunity to manage their lands in ways that contribute to climate change mitigation by encouraging carbon sequestration. This can be done by increasing carbon inputs and uptake, decreasing or preventing carbon releases, or both.
How to increase carbon stored: A practice, known as “Carbon Farming” involves implementing practices that are known to improve the rate at which CO2 is removed from the atmosphere and converted to plant material and/or soil organic matter. Carbon farming is successful when carbon gains resulting from enhanced land management and/or conservation practices exceed carbon losses. Management practices that increase the amount of photosynthetically-captured carbon held, or “sequestered”, in long-term carbon pools on the farm or ranch, include soil organic matter, perennial plant roots and standing woody biomass. This results in a direct reduction in the amount of carbon dioxide in the atmosphere.
Loren Poncia, Stemple Creek Ranch, has implemented a carbon farming plan to not only sequester carbon but enhance the quality and quality of his forage. Loren owns a grass based beef operation, and his animals are born, raised and finished on grass. He needs to supply adequate nutrition for his cattle have proper growth to his meet market goals. As part of his carbon plan, Loren implemented a grazing management plan, to promote perennial grasses growth. Perennials have deeper root systems, and will store more carbon, deeper in the soil. Loren checks the quality of his forage using a spectrometer, measuring sugar levels in the grasses, (Figure 1).
Expanding Carbon Markets: There is a growing body of work suggesting that significant amounts of carbon can be stored in soil. This is particularly true on rangeland, which houses approximately 30 percent of terrestrial carbon stocks in addition to a substantial amount of aboveground carbon in trees, plants and grasses, and can hold carbon over longer periods of time.2 Expanding investment in programs, such as Carbon Farming and the Healthy Soils Program, can support agricultural practices that add to these stocks, creating potential markets to pay ranchers for sequestering carbon.3 Moreover, given the well-established relationship between soil organic matter (of which an average of 50 - 56% is carbon) and the ability of soils to retain water,4 such a market could contribute to watershed function, natural groundwater recharge and overall water provision.
The scientific consensus surrounding the relation between greenhouse gas (GHG) emissions and global climate change has indicated a clear need for the US to find new ways to reduce emissions of these gases and the concentrations in the atmosphere to avoid significant and potentially catastrophic environmental changes. Land management for carbon sequestration is one of many opportunities available to the US, more locally in California, to reduce their net emissions of GHGs, particularly CO2. Carbon-oriented management of rangelands may offer landowners the opportunity to obtain a new source of income while simultaneously helping to mitigate climate change. The payment for ecosystem services, such as carbon sequestration, may be a potential solution to climate change.
2 FAO, 2009; Flynn, A., et al., 2009; White, R., et al., 2000.
3 De Gryze, S., et al., 2009.
4 Huntington, 2007; Pribyl, 2010; Rawls et al., 2003.
- Author: Van Bustic, UCCE and UC Berkeley
- Author: Matthew Shapero, UC Berkeley
- Author: Diana Moanga, UC Berkeley
- Author: Stephanie Larson
From UCANR California Agriculture magazine
The purchase of conservation easements on agricultural land is one approach to preventing residential development on working landscapes. The authors present a low-cost tool for assessing ecosystem service values across large areas, a step toward quantifying the benefits of land conservation.
Purchases of private land for conservation are common in California and represent an alternative to regulatory land-use policies for constraining land use. The retention or enhancement of ecosystem services may be a benefit of land conservation, but that has been difficult to document. The InVEST toolset provides a practical, low-cost approach to quantifying ecosystem services.
Using the toolset, we investigated the provision of ecosystem services in Sonoma County, California, and addressed three related questions. First, do lands protected by the Sonoma County Agricultural Preservation and Open Space District (a publicly funded land conservation program) have higher values for four ecosystem services — carbon storage, sediment retention, nutrient retention and water yield — than other properties? Second, how do the correlations among these services differ across protected versus non-protected properties? Third, what are the strengths and weaknesses of using the InVEST toolset to quantify ecosystem services at the county scale?
We found that District lands have higher service values for carbon storage, sediment retention and water yield than adjacent properties and properties that have been developed to more intensive uses in the last 10 years. Correlations among the ecosystem services differed greatly across land-use categories, and these differences were driven by a combination of soil, slope and land use. While InVEST provided a low-cost, clearly documented way to evaluate ecosystem services at the county scale, there is no ready way to validate the results.
Vernal pools exist in areas of a grassland where there is an isolated area of compacted clay or bedrock. This is because the water cannot penetrate it and therefore, stays on the surface instead of absorbing into the soil. Depending on their size and amount of rainfall, they may fill and dry up many times within a season, or may not fill at all in a drought. Many species of wildlife, including birds and amphibians, depend on these pools. They are a cache of fresh water and food and, for some, a good place to lay their eggs because they are safe from predation by fish.
For the first time in four years, US Fish and Wildlife Service (FWS) opened grazing permits for several properties in the Santa Rosa plains, allowing grazing. Grazing was returned to these properties because its removal caused vegetation to over grow, reducing habitat for the endangered species present. Not having this grazing “disturbance” resulted in a species loss; the very species that were to be protected. Two examples of grazing benefits are listed below.
California Tiger Salamander
Managed livestock grazing is thought to benefit the habitat for California tiger salamander (Ambystoma californiense) (Fig 1). Some Bay Area populations of these salamanders depend on ground squirrel burrows for refuge sites. Livestock grazing keeps vegetation low, making the grasslands more suitable for California ground squirrels (USFWS 2003). Salamanders that inhabit vernal pools may also benefit from grazing. These ephemeral pools are wet only during the winter/spring rainy season, and too much vegetation in and around their edges can cause drying pools to lose depth too quickly. Because it reduces this vegetation, grazing can keep the pools wet longer, giving salamander larvae more time to grow up (USFWS 2004).
Opportunities for Native Plants
Grazing of non-native vegetation is essential to create opportunities for many native grassland plants. For example, there is only a single remaining natural population of the federally-endangered Sonoma spineflower (Chorizanthe valida) (Fig 2) and it declined dramatically after livestock was removed from its habitat area (Davis and Sherman 1992). Similarly, populations of the federally-endangered Contra Costa goldfields (Lasthenia conjugans) and Santa Cruz tarplant (Holocarpha macradenia) plummeted and died out when grazing was removed from their habitats (USFWS 2005; Hayes 1998).
Nowadays, 90% of the US's vernal pools have disappeared due to human encroachment and land conversion. Like the rangelands they exist on, they can be beautiful and vital places if properly managed! With the arrival of the Spanish missionaries, Sonoma County's grasslands changed dramatically. They became dominated by non-native annual plants, mostly from the grasslands of the Mediterranean Basin. Despite the general replacement of native plants by these non-natives, enough native species have survived to prompt global recognition of our grasslands as hot spots of biodiversity.
Because livestock grazing (primarily by cattle) can effectively reduce the biomass, height, and thatch accumulation produced by non-native annual plants, it has become an essential tool for managing our local grasslands. Grazing has been shown to be a benefit by
reducing the risk of a catastrophic wildfire, maintaining and enhancing habitat for many native grassland plants and animals,
and maintaining the open character of our iconic grasslands and oak savannas.
Ranchers should be encouraged to continue their sustainable livestock production practices and their long history of good stewardship. In addition, they should be compensated for implementing other conservation services on rangelands./h2>/h2>/table>
Rangeland owners in the Bay Area face substantial pressure to develop their land. The short term financial gains from developing rangeland for vineyards or residential construction can be very large. In Sonoma and Marin Counties several conservation groups, including the Marin Agricultural Land Trust and the Sonoma County Agricultural Preservation and Open Space District, are dedicated to preserving rangeland and the cultural and environmental amenities that only open space can provide. The most common instrument for rangeland preservation is a conservation easement. The University of California Cooperative Extension (UCCE), in partnership with UC Berkeley researchers, is currently engaged in a project that explores the
possibility of simultaneously expanding rangeland conservation and
increasing rancher welfare through the use of
novel conservation easement payment structures,
including annuities and variable
Payments for Ecosystems Services (PES).
A conservation easement is an agreement between a landowner and a conservation group that ensures that a parcel of land is not further developed. Conservation easements are permanent—even if the original owner decides to sell the parcel, the easement remains in force. Conservation groups typically compensate landowners by paying them a substantial one-time lump sum. Since an easement decreases the resale value of the parcel, the landowner's property tax liability is often decreased as well. Another important motivation for landowners is securing financial stability for future generations (Rilla and Solokow 2000). Conservation groups are motivated by a range of social, environmental, and ecological goals, including preservation of public goods: open space, biodiversity, soil health, and rural lifestyles (Cross et al 2010).
Under PES systems landowners are monetarily compensated for
making changes to their land management practices.
For example, the owner of a parcel of forest land might receive an annual payment in return for abstaining from logging on the parcel. Depending on the terms of the agreement, the land owner could receive the same payment amount every year, called an annuity, or a variable payment based on the level of ecosystems services that the parcel provides. A conservation group would regularly monitor the parcel to ensure that the terms of the PES agreement had not been violated. PES systems have been successfully implemented in France, Costa Rica, Honduras, and Brazil, but are relatively rare in the United States.
Many families in Sonoma and Marin Counties have been ranching on their parcels for several generations, developing deep and personal connections to their land. As a result, those landowners may have a greater interest in whether or not subsequent generations continue to ranch on their parcels. These landowners could potentially find an annuity more attractive than a lump sum, and a PES based on the amount of residual dry matter (RDM) on the parcel, which would reward ranching and active land management, might be more attractive still.
PES and annuity payment structures would expand the menu of land conservation options available in Sonoma and Marin Counties,
without restricting conservation groups' ability to continue to offer traditional lump sums. With more options comes the possibility of more land conservation, more money in the hands of ranchers, and better alignment between rancher and conservation group motivations.
The class learned about the direct link between urban consumers and local food producers, providing a powerful conduit for educating the public about the importance of local food production and rangeland management. Sonoma and Marin Counties are perfect models for demonstrating how
preserving family farms contribute to
social, economic and ecological sustainability at
local, regional and even national levels.
Ranching PRNS, albeit smaller scale, remains a local industry, which provides job creation, training and business succession, and market expansion for many other ranchers and farmers.
Through the 1980s and 1990s and into the early 2000s, efforts to conserve threatened and endangered (special status) species on western rangelands often meant removing livestock ranching. Research findings, demonstration results, and failed conservation efforts in recent years involving endangered species has supported the continuation of livestock ranching and the reintroduction of grazing to some rangelands that were “protected” through grazing removal. At the landscape level,
research has demonstrated that livestock ranching
maintains extensive, open spaces by
reducing land use conversion, fragmentation of habitat,
and vegetation type conversion from invasion of brush.
Threats to native biodiversity, including special-status species, are likely to increase with removal or decrease of grazing. Research and experience have shown that grazing is strongly linked to maintaining habitat for some special-status species on PRNS lands, while they have been inconclusive for others. Sonoma alopecurus (Alopecurus aequalis var. sonomensis) is found in eight naturally occurring populations in Sonoma and Marin Counties; the four sites in Marin County all occur at PRNS and are all grazed by cattle; Sonoma spineflower found solely in a grazed pasture at PRNS. Tiburon paintbrush and Marin dwarf flax occur on serpentine grasslands, with six occurrences of Marin dwarf flax on Golden Gate National Recreation Area (GGNRA) grazing lands. PRNS staff concluded, “Marin dwarf flax may benefit from a moderate level of cattle grazing through the reduction of taller competing vegetation as the flax is subject to shading by competing grasses or may be suppressed by build-up of thatch from previous year's herbage if left ungrazed.” (USNPS 2001).
Documented research, along with good stewardship provided by generational ranchers, has demonstrated the benefits provided to the ecosystems at Point Reyes National Seashore.
U.S. National Park Service. 2001. Biological Assessment on the Renewal of Livestock Grazing Permits in Point Reyes National Seashore and the North District of Golden Gate National Recreation Area Marin County, California. 65 pp.