The Mountain Meadows Restoration Project consists of two (2) projects; Greenville Creek and Upper Goodrich. Both projects are on private lands owned by Shasta Forests, LLC, an industrial timberland owner. The lands are managed by Wm. Beaty & Associates. Beaty's forester contacted Plumas Corporation in 2010 about assistance in developing several restoration projects. Shasta Forests, LLC is interested in restoring their extensive meadow lands. The project(s) data collection, analysis and conceptual design development was been funded by both Intermountain West Joint Venture (IWJV) capacity building grants and National Fish and Wildlife Foundation (NFWF) Sierra Meadows Program. Implementation funding was provided by the California Department of Fish & Wildlife's Wetlands Restoration for Greenhouse Gas Reduction Program, with cost share support from the landowner, Ducks Unlimited, Point Blue, and Plumas Corporation.
The Greenville Creek project encompasses approximately 181 acres. Two discrete stream channels occupy this portion of the Mountain Meadows valley, Greenville Creek on the west with a watershed area of 3.5 mi2 and Stroing Creek on the east with a watershed area of 4.9 mi2. Both creeks flow northwest into Mountain Meadows Reservoir and, ultimately to the North Fork Feather River. Stroing Creek and Greenville Creek have been manipulated significantly for irrigation both within the project area as well as upstream. The south portion of Mountain Meadows valley is dominated by an extensive Holocene-era alluvial fan with the fan crown just west of the project area. Greenville Creek develops distributary channels as is flows off the east flank of the fan. The gradient of Greenville Creek transitions from 1% at the upstream end to less than 0.1% at the downstream end of the project. Stroing Creek occupies the east margin of the fan with gradients ranging from 0.5% at the upstream end to less than 0.1% at the downstream end of the project. There are well defined remnant channels for both Greenville Creek and Stroing Creek for normal high water and expansive floodplain for high flow dispersion.
The Greenville Creek project site was restored in August 2016 utilizing the partial fill technique, often referred to as ‘pond and plug’. Both incised channels were treated, Greenville Creek and Stroing Creek. A total of 24,500 cubic yards of native material was excavated to eliminate the multiple gullies as conduits for flow. Fill material was excavated from 15 borrow areas (ponds) and used to construct 17 plugs, resulting in a total pond water surface area of 7.8 acres, and a total plug surface area of 4.5 acres. Approximately 181 acres of meadow floodplain function was restored at Greenville Creek meadow. Greenville and Stroing creeks did not have perennial streamflow before or after restoration. In addition to the meadow floodplain restoration, three damaged 36” culverts on Stroing Creek where the creek crosses under the road at the upstream end of the project were replaced. The culverts were replaced with new culverts of the same number and diameter, set at an elevation consistent with the restored base level of the project. Nine one- to two-foot high headcuts occurring at the interface of stream flow with Mountain Meadows Reservoir were also treated. The reservoir fluctuates significantly intra-annually based on Pacific Gas & Electric hydroelectric generating operations. These headcuts have developed where overland flow from the meadow becomes concentrated in small swales not associated with the active stream channels. These headcuts activate when normal overland flow occurs and the reservoir is not yet full. The restoration work incorporated 20 cubic yards of 1 foot minus rock into each headcut (totaling 180 cu. yds.), providing a sloping, armored pathway for these flows to enter the reservoir without further cutting into the meadow. Both the culvert replacement and the headcut treatment enabled a seamless transition for flows into, and out of, the Greenville Creek treatment area. The remnant channel(s) are 7,350 feet long with an average floodplain width of >1000 feet. Topsoil was salvaged from borrow areas and stockpiled adjacent to plug areas for top dressing the fill. Existing mature meadow sod and willows were transplanted from the gully bottom prior to excavation or filling. Transplants were used to line the lower margins of the plugs for overland flow protection. Native seed and certified weed free rice straw mulch was spread by hand on finished plugs. All rock, culverts, and fencing for the Greenville Creek project were provided by the landowner. Fencing of the Greenville Creek project site was completed in October 2017.
The Upper Goodrich project is located on an un-named tributary to Goodrich Creek. The project is approximately 4,800’ long and encompasses approximately 73 acres of meadow/floodplain restoration. The project consists of 2 parallel meadows, referred to as Tributary Meadow and Main Meadow, which drain watershed areas of 1.5 mi2 and 4.5 mi2, respectively. The two meadows converge in the lower third of the Tributary Meadow. There is a zone of multiple headcuts in both meadows. The project begins at the zone of headcuts in each meadow and treats the moderately incised gully channels downstream to the beginning of stable, un-incised reach just upstream of its confluence with Goodrich Creek. The principal mechanism for this channel incision appears to have been a system of railroad logging grades constructed up both meadows as well as across the Tributary Meadow. The upper portions of both meadows lack remnant channels and were likely sheet flow systems. This sheet flow character was restored/maintained where indicated. Remnant channels develop where the accretion of streamflow and sediment supply is sufficient to develop and maintain a defined channel. Both meadows have a combination of sheet flow and remnant channels. De-watering of the historic meadow resulting from channel incision initiated conifer encroachment. The gradient of the Tributary Meadow is a relatively consistent 1%. The Main Meadow gradient is 1% at the upstream end, increasing to 3% as it exits toward the Tributary Meadow. This necessitated the construction of a rock-armored plug.
The Upper Goodrich site was implemented in July 2016, using a near-complete fill technique, which entailed the excavation of 30,500 cubic yards of native material to eliminate the gully as a conduit for flow. This material came from 17 borrow areas (ponds) and was used to construct 23 plugs. After restoration, the total pond water surface area created was 4.3 acres, and total plug surface area was 6.5 acres. The remnant channels total 6,100 feet in length with an average floodplain width of 200 feet. Topsoil was salvaged from borrow areas and stockpiled adjacent to plug areas for top dressing the fill. Existing mature meadow sod and willows were transplanted from the gully bottom prior to excavation or filling. Transplants were used to line the lower margins of the plugs for overland flow protection. Native seed and certified weed free rice straw mulch was spread by hand on finished plugs. Archaeological sites on the Upper Goodrich project were monitored during construction per mitigation developed during tribal consultations and Army Corps of Engineers permit requirements. Project performance monitoring in April 2017 identified some maintenance needs on the Upper Goodrich site due to high winter/spring flows over the newly constructed plugs. Two small reaches required some repair work that was completed in November 2017 and 2018. Fencing at Goodrich was completed in June 2018. A total of 73 acres of meadow floodplain function was restored at the Upper Goodrich meadow. The Upper Goodrich channels did not have perennial streamflow before or after restoration.
Willow staking was done at both meadows in April 2017 by the California Conservation Corps with funds provided by Ducks Unlimited. A total of approximately 7000 willow stakes were planted, 12 wild rose plants were transplanted, and two willow dams were constructed at the bottom (downstream) outlet of the Greenville project site. An additional 600 willow stakes were planted at the Upper Goodrich project site near the confluence of the main channel and the side channel. Supplemental plantings were done in the fall 2018 by local students from Westwood Jr./Sr. High School in collaboration with Point Blue's Students and Teachers Restoring A Watershed (STRAW) program. The project site was used as a pilot for their STRAW program in the Sierras. Plumas Corp worked with Point Blue staff in October 2018 to mark restoration planting sites in the field, finalize logistics for the planting day, and collect and prep willows for planting. On November 1st, 2018 approximately 25 students from Westwood Jr. and Sr. High School planted over 100 willows on the Greenville project site. As of the end of the 2019 growing season, the success rate of all planted willows on both projects was estimated at 50%.
In 2019, Plumas Corporation staff met with Beaty & Associates land managers and the grazing lessee to recap current grazing strategies and plan future management for the Greenville Creek, Upper Goodrich and East Creek (control meadow) project areas. The lessee’s family has held the lease for over 60 years, and in that time has witnessed much of the degradation that has occurred. As discerned from project data collection and analysis, as well as observed by the lessee, many of the stressors on the landscape have been related to roads and wholesale channel manipulation for water management in addition to insufficient infrastructure to control seasonal livestock movement. Because of the shared history, the lessee is in full support of implementing a more sustainable livestock management strategy for the existing above mentioned and future projects. The plan elements below are also set in the larger context of a grazing strategy being developed in late 2019 collaboratively with Beaty & Associates and Sierra Pacific Industries, the two principal landowners within the Mountain Meadows Basin, along with the Trust for Public Lands (TPL) and several other grazing lessees. Pacific Gas & Electric ownership of adjoining meadow areas encompassed under its maximum reservoir elevation does complicate some infrastructure and management control measures.
The aspects of grazing management for the two projects and control meadow are as follows:
1) Identify and implement pasture fencing.
2) Provide dispersed water and salting locations to avoid severe trailing.
3) Establish sustainable livestock numbers and timing of pasture utilization.
None of the subject project areas have irrigation available, resulting in substantial variability in the moisture regime, presence, and timing, both interannually and year-to-year within each project. Subsequently, this approach is intended to be guided by thresholds rather than hard calendar dates. The threshold for aspect #1 is to provide fencing that segregates meadow areas by timing of appropriate moisture conditions to reduce/eliminate ‘post-holing’ from cattle hooves when excessively wet. Some minor hoof disturbance is desirable to maintain species diversity, particularly for mesic forbs and graminoids. Fencing is typically designed to allow access to more xeric zones as they become suitable for foraging earlier in the season, while protecting more mesic zones until soils can support hoof action from cattle. The threshold for aspect #2 is to reduce/eliminate intensive trailing that exposes bare soil pathways parallel to water flow. The lessee will observe trailing intensity throughout the growing season and adjust salting locations as needed. Aspect #3 is intended to balance livestock numbers with pasture acreage and timing of best forage palatability to ensure balanced forage utilization with cost-effective operator management actions. Future stocking rates will be adjusted based on forage production and timing. Approximately 40 similar meadow restoration projects have used these threshold triggers to successfully re-introduce livestock production while maintaining a robust, functional meadow ecosystem.
The GHG research associated with this project consisted of five parts: 1) Monitoring of soil C stock and GHG flux change associated with restoration in the projects implemented above; 2) Assessing soil C change prior to restoration in thirteen Sierra Nevada meadows; 3) Measuring changes in ecosystem C and N stocks and changes in soil C chemistry across a 20-yr chronosequence of time since restoration; 4) Assessing how soil C stocks change among vegetation communities in meadows; and 5) Performing laboratory-based studies to determine the mechanisms behind soil C stabilization and sequestration.
This project was part of a larger partnership research effort of the Sierra Meadow Restoration Research Partnership (SMRRP), using GHG research protocols for the “focus” meadows (i.e. more intensive data collection). Protocols developed and utilized by the SMRRP research meadows (including Upper Goodrich and Greenville Creek) can be found in the project report on Plumas Corp's website. The two treatment meadows, Greenville Creek and Upper Goodrich, were sampled in the un-restored condition in 2015 and 2016 and in the restored condition in 2017, 2018, and 2019. Two additional meadows that were previously restored, Red Clover McReynolds (2006), and upper Clarks Creek (2001), were each concurrently sampled in 2016 and 2017 to determine longer term potential for GHG reduction. An un-restored meadow, East Creek, was sampled as a control for the Upper Goodrich and Greenville Creek project sites. The treatment and restored meadows were paired, based on flow regime, parent material, and elevation. The Red Clover / Greenville pair has similar parent material and elevations, and the Goodrich/ upper Clarks pair is intermittent.
For soil GHG sampling, static chamber collars were installed in the soil at each site, within an approximate 1.4 hectare grid (130m x 180m) placed every 30 meters (i.e. 24 chambers per meadow) in June 2015, using the static chambers described by Reed et al. 2018. Soil GHG flux samples were collected approximately every three weeks during the growing season, and monthly in the non-growing season, along with soil pore water and soil temperature. During snow-covered months, sites were sampled two to three times to establish low rates of subnivean soil GHG flux. Samples were analyzed at the University Nevada Reno Soil Ecology Laboratory using a gas chromatograph (Shimadzu GC-2014; Reed et al. 2018). A 100- year molar atmospheric forcing ratio of 25 and 298 for CH4 and N2O, respectively, was used to convert CH4 and N2O to CO2 equivalents (CO2e’s).
Soil carbon (C) stocks, soil bulk density, soil C content, and belowground and aboveground plant biomass was collected prior to restoration (2015/2016) and in the second year after restoration (2018). Soil C, bulk density, and roots were collected with a slide hammer (AMS Samplers, American Falls, ID) or a diamond-bitted power auger (Rau et al. 2011) in 15 cm increments to 60 cm. From 60-100 cm, soil C content was collected with a slide hammer, power auger, or a bucket auger and bulk density was assumed to be constant. Soil C and root sampling occurred within 1 m of the GHG collars. Sampling was stratified by depth, such that more samples (12) were collected in the 0-15 cm than in the 75-100 cm depth (3-4) to account for expected higher variability and soil C concentrations in the surface samples than at depth. Soil bulk density was measured using dry sieving pre-restoration, reflecting common soil sampling protocol. These sites were among the first samples to be collected as part of the SMRRP project. However, the Soil Ecology Lab switched to wet sieving as other samples from the SMRRP project were processed and it was discovered that dry sieving did not provide reliable bulk densities in high organic matter soils. Therefore, post-restoration soils were wet sieved from these sites, and post-restoration bulk density estimates were used for both pre- and post-restoration soil C stock estimates. The restoration is not expected to have had a substantial impact on bulk density. Soil C and N content were measured by combustion in an elemental analyzer (Costech 4010, Valencia, CA) in the Soil Ecology Lab. While soil C stocks from all depths are presented, the statistical analysis was focused on the shallow depths (0-45 cm) where the greatest change due to restoration was expected. Plant biomass was clipped at peak productivity (aboveground net primary productivity) and at senescence (to determine the quantity of litter produced). Plant community composition was visually estimated.
Co-benefit monitoring objectives for the project were:
• A three-foot elevation increase in spring and early summer groundwater elevations within one year.
• A 102 acre-feet increase in shallow floodplain aquifer volume (a 3’ increase in shallow floodplain aquifer depth, divided by a shape factor to account for alluvial basin boundary, multiplied by acreage and soil porosity.
• A 100% increase in vegetative meadow productivity within two years.
• A 100% increase in the ratio of wet meadow plant species to dry meadow species within two years.
• Enhancement of 253 acres of mountain meadow floodplain with 12.1 acres of surface water in ponds, and improved riparian habitat vegetative vigor for waterfowl and sandhill cranes.
Groundwater elevation monitoring began with the installation of nine groundwater wells, three at Upper Goodrich on June 19, 2014, four at Greenville Creek on June 25, 2014, and two at East Creek (control meadow) on July 2, 2015. Wells at Goodrich and Greenville were installed and measured in 2014 and early 2015 with planning funds from National Fish & Wildlife Foundation, prior to the CDFW grant award. Groundwater levels within the wells were measured monthly when the project areas were accessible, from June 2014 (Goodrich and Greenville) and July 2015 (East), through three years after restoration construction into early 2020. Vegetative meadow productivity was monitored using the SMRRP protocol, as summarized for the GHG research. Samples were co-located with gas sample plots. Species were grouped into wetland status following the Army Corps of Engineers State of California 2014 Wetland Plant List (Lichvar et al 2014), with the percentage of wetland plants compared before and after treatment. Drying methods were standardized across all meadows in the SMRRP. Wildlife habitat value was measured with bird point counts conducted by Point Blue. Birds were surveyed at nine locations within the Greenville Creek project area, and eight locations within the Upper Goodrich project area. Survey locations were established along the two main flow channels at Greenville Creek and down the center of the meadow at Upper Goodrich. All survey stations were spaced at least 250 meters apart to avoid counting the same individuals from adjacent survey stations. Sample locations were visited twice during the peak of the bird breeding season (late May-June) in pre-project (2015 and 2016) and post-project (2017 and 2018) conditions. Surveyors conducted standardized five-minute exact-distance point counts at each sample location (Ralph et al. 1995). With the aid of rangefinders, surveyors estimated the exact distance to individual birds at the time of initial detection. Surveyors counted from sunrise to four hours after sunrise, and did not count in inclement weather (i.e., precipitation, fog, or high wind) that would reduce detection probability. Photo points entered into a Global Positioning System and co-located with the groundwater wells were used to document overall changes in the vegetation and landscape. Photos were taken annually in mid-summer, as well as monthly when groundwater wells were measured. Flow duration was initially planned for measurement at the bottom of each project area with a HOBO data logger placed in the channel within a stilling well. Dataloggers would have been installed as early as the project area was accessible in 2015, and downloaded monthly through the summer months on an annual basis until the channel was dry. However, the prolonged drought and delays in contract award and execution resulted in no pre-project data collection of stream flow duration, and on June 1, 2015 the channels were already dry, with the actual date of the cessation of flow in 2015, and all other pre-project years, unknown. Without pre-project data on the cessation of flow, post-project data collection would be moot. Therefore, we did not pursue flow duration as a co-benefit parameter to be monitored. However, in April 2017 we were awarded funding to monitor the hydrology of Sierra meadows through the Wildlife Conservation Board’s Stream Flow Enhancement Program. The monitoring project supported the installation of a stream flow monitoring station on Goodrich Creek at Hwy 36 (approximately 3 miles downstream of the Upper Goodrich project) in June 2017. The station measures the co-benefits of surface water flows and water temperatures in the watershed, which contributes additional co-benefit monitoring data to these projects.
Restoration of the ecological function of 254 acres of degraded mountain meadow habitat was accomplished through restoring the meadow channel/floodplain connection in Greenville Creek Meadow (181 acres) and Upper Goodrich Meadow (74 acres). The project description above provides more detail on the how the objective was met through the restoration activities that were implemented at each meadow.
Co-Benefit Objective Outcomes
1) A three-foot elevation increase in spring and early summer groundwater elevations within one year.
Groundwater wells were installed in June of 2014. Figures 2 and 3 show the groundwater well and greenhouse gas sample plot locations for each project. The Greenville Creek and Upper Goodrich meadow restoration projects were implemented in August and July of 2016, respectively.
The climatic regime during the project period encompassed drought (2014-2015 & 2017-2018), normal (2015-2016), and wet years (2016-2017 & 2018-2019). Through the five-year period of record nearby local automated weather stations contained data gaps. To apply a consistent precipitation reference, the Northern Sierra 8-Station Index was used to characterize the Water Year (WY) precipitation. The Northern Sierra 8-Station Index (8SI) Water Year average is 51.8” (inches). To illustrate the precipitation variability, the 8SI water year index values for 2014-15 and 2015-16 were 37.2” and 57.9”, respectively. The 8SI value for water year 2016-17 was 94.7”. The subsequent 2017-18 water year had an 8SI index of 41.0”.
Prior to restoration, the groundwater elevation seldom reached the ground surface in early spring and summer. Two years of pre-project data collected April through June 2015 and 2016 were compared to post-project groundwater levels during the same period one year after project construction. The average elevation increase from April through June in the first year post-project on Greenville Creek was approximately one foot, and on the Upper Goodrich it was approximately two feet. While groundwater elevation increases did not quite meet the three foot rise in the first year as projected, a rise in groundwater elevations did occur. Groundwater levels during the early spring and summer in 2018 and 2019 were sustained at or near the ground surface much longer than in pre-project or the first year post-project. The objective’s intent to demonstrate the increase in groundwater elevations as a result of the restoration was met. As mentioned previously, neither project area had perennial streamflow before or after restoration. Seasonal drawdown of shallow groundwater was not expected to change, only the seasonality of the occurrence.
2) A 102 acre-feet increase in shallow floodplain aquifer volume (a 3’ increase in shallow floodplain aquifer depth, multiplied by the respective shape factors, multiplied by acreage and soil porosity.
There are several approaches to quantifying groundwater benefits related to project-induced change. These are Absolute Net, Environmental Net and Gross groundwater changes. To quantify the change in shallow floodplain aquifer volume we evaluated groundwater level changes using both “Absolute Net” and “Environmental Net”. Absolute Net is the change from the lowest annual pre-project groundwater level to the lowest annual groundwater level post-project. This would represent that portion of the meadow alluvium that has changed to permanently saturated. Typically, this is water that is more than 4 feet below the meadow surface. This groundwater can provide downstream recharge during extended drought periods but, being disconnected from the surface, has little local annual ecosystem benefits. Increases in the deeper saturated zones does allow for quicker annual recharge of the near-surface groundwater. Environmental Net is the change from the lowest annual high groundwater level pre-project to the highest annual groundwater level post-project. This represents the change in groundwater that most affects the meadow ecosystem by saturating the soil to the surface for extended periods of time annually, then discharging groundwater to streamflow in low flow periods. It is this annual flooding/draining that drives changes in the physical processes that sustain healthy vegetative communities, aquatic and terrestrial habitats, and carbon sequestration.
Final Acre-foot quantification formula: (Average water level change in feet) x (total acres of restored water table) x (designated shape factor) x (.32 effective porosity factor) – (17% evapotranspiration factor in top 2’ of soil profile). The below quantification's compare Absolute Net and Environmental Net analyses of meadow groundwater change.
Greenville Creek (.68 X 181 ac. X 1.0 X 0.32) -17% = 42 AF
Upper Goodrich (1.89 x 73 ac. X 0.75 X 0.32) -17% = 27 AF
Absolute Net Total = 69 AF
Greenville Creek (4.01 X 181 ac. X 1.0 X 0.32) -17% = 192 AF
Upper Goodrich (4.73 x 73 ac. X 0.75 X 0.32) -17% = 69 AF
Environmental Net Total = 261 AF
The soil porosity value of 0.32 was estimated from typical porosity values for different Unified Soil Classification System (USCS) soil types at normally consolidated conditions. The USCS soil type description used for the Greenville and Goodrich project soils is inorganic clays, silty clays, and sandy clays of low plasticity. The soil porosity range for these soil types is 0.21 to 0.41 (https://www.geotechdata.info/parameter/soil-porosity.html). Over time as root biomass increases due to greater productivity, the soil porosity will increase. The 0.32 soil porosity value is a mid-range conservative estimate for these projects. A meadow shape factor of 1.0 is used for the un-confined Greenville Creek meadow. A meadow shape factor of 0.75 is used for the trapezoidal-shaped Upper Goodrich Creek meadow, a conservative estimate based on the bounded alluvial shape of affected groundwater.
Concurrently with post-restoration groundwater monitoring at Upper Goodrich, in 2017-2019, total groundwater storage potential was determined using seismic data collected by Kevin Cornwell (California State University, Sacramento), and funded through Plumas Corporation’s Sierra Meadows Hydrology Monitoring Project (Wildlife Conservation Board, grant #WC-1651 MM). The seismic model study area included only the south finger (Tributary Meadow) of the meadow (43 acres) and conservatively estimates 27 AF of total groundwater storage potential. The estimated 27 AF calculated from this method, while not directly comparable to the “Absolute Net” calculation above (the seismic approach estimates total groundwater storage while the “Absolute Net” calculates change in groundwater storage pre- and post-restoration), does help support some of the calculation assumptions used for the GHG study. Several more Sierra Meadows scheduled for restoration in 2020 are currently monitored by Plumas Corporation and have had seismic surveys completed and groundwater data collected pre-restoration which will allow for further comparisons in calculating groundwater storage potential in montane meadows. A detailed discussion of the seismic survey approach for determining groundwater storage potential and the specifics for Upper Goodrich can be found in the “2018 Sierra Meadows Hydrology Annual Report”
3) A 100% increase in vegetative meadow productivity within two years.
Overall, vegetative meadow productivity increased by greater than 100% at the Greenville and Upper Goodrich sites. In the unrestored control site, aboveground plant biomass increased significantly between 2015 (38 g m-2) and 2018 (61 g m-2), a 60% increase that reflects differences in weather between the years. However, restoration increased aboveground plant biomass at the treatment sites beyond the increase attributed to interannual variation: aboveground plant biomass at Upper Goodrich increased 176% (25 to 69 g m-2) and at Greenville Creek increased 429% (34 to 180 g m-2).
The cover data also support the observed changes in productivity at the restored meadow. The percent cover of bare ground decreased slightly, but not significantly, in the unrestored control site (from 57% in 2015 to 44% in 2018). Restoration significantly decreased the percent cover of bare ground relative to the interannual variability; percent bare ground at Goodrich significantly decreased from 57% pre-restoration to 40% post-restoration and percent bare ground at Greenville significantly decreased from 43% pre-restoration to 7% post-restoration.
4) A 100% increase in the ratio of wet meadow plant species to dry meadow species within two years.
Restoration had a notable impact on the percentage of plants that were obligate or facultative wetland-rated species. The overall percentage of wet meadow species increased between approximately three-fold and five-fold. At Upper Goodrich, the percentage of wet meadow species (obligate and facultative wetland species) increased between pre- and post-restoration from 5% to 17%. At Greenville Creek the percentage of wet meadow species increased between pre-and post-restoration from 8.5% to 44%. There was essentially no change in the percentage of wet meadow species at the unrestored control site, which had a non-significant decline from 15% (2015) to 13% (2018). Species composition changed due to restoration as well; interannual variability accounted for changes in species composition on axis 1 of our ordination at the unrestored control (East Creek), but restoration impacts accounted for variation in species composition at Greenville and Goodrich.
5) Enhancement of 253 acres of mountain meadow floodplain with 12.1 acres of surface water in ponds, and improved riparian habitat vegetative vigor for waterfowl and sandhill cranes.
The analyses of meadow birds in the Sierra-Cascades region are generally limited to a subset of focal species selected a priori. A focal species group is likely to provide a better measure of the health of meadow habitat than using all species combined (Chase & Geupel 2005). These 13 focal species identified by Campos et al. (2014) are: Wilson’s Snipe (Gallinago delicata), Red-breasted Sapsucker (Sphyrapicus ruber), Calliope Hummingbird (Selasphorus calliope), Willow Flycatcher (Empidonax traillii), Swainson’s Thrush (Catharus ustulatus), Warbling Vireo (Vireo gilvus), Wilson’s Warbler (Cardellina pusilla), Yellow Warbler (Setophaga petechia), MacGillivray’s Warbler (Geothlypis tolmiei), Song Sparrow (Melospiza melodia), Lincoln’s Sparrow (Melospiza lincolnii), Mountain West White-crowned Sparrow (Zonotrichia leucophrys oriantha), and Black-headed Grosbeak (Pheucticus melanocephalus). This suite of focal species reach their greatest breeding density in montane meadow and riparian habitat in the study area, are appropriately sampled by passive point count methods, and are expected to respond positively to habitat conditions created by the restoration of meadow form and function, specifically: (a) floodplain inundates at a
Since only three focal species were detected (1 in Upper Goodrich, and 2 in Greenville), we calculated the richness of all species detected. The total number of each species detected by year within 100 m from observers (the point count center) is also presented. For the analyses naïve point count detections within 100 m of the observer were used, uncorrected for detection probability, thus abundance metrics herein represent indices rather than true densities (Johnson 2008).
A total of 34 species in and surrounding the Upper Goodrich Creek restoration project within 100 m of the center of survey stations were detected across the four years of surveys. A single Red-breasted Sapsucker was the only meadow focal species detected and that was from 2015. The most frequently detected species were: Dark-eyed Junco, Red-breasted Nuthatch, Chipping Sparrow, Western Wood-Pewee, and Brown-headed Cowbird. Overall there were relatively few birds detected within the meadow itself with far more species and individuals in the forest on the meadow edge. There was a strong decline in total species richness across years at Upper Goodrich at the 100 m distance. One of the species that was more prevalent pre-restoration that declined post was Mountain Bluebird, with 10 detections pre-restoration and only 1 post. They may prefer drier meadows with more bare ground, and thus restoration may have reduced habitat suitability for them. The other species that declined from pre- to post-restoration were almost exclusively conifer forest associates. As such, it is unlikely the restoration was the cause of this decline. To evaluate this further, the 100 m data was compared to 50 m data to reduce the amount of the sampled area that was conifer forest. In doing so, the 50 m data showed there was no change in richness from pre- to post-restoration, supporting the hypothesis that declines in the 100 m data were driven by changes in the surrounding forest bird community. Due to the narrowness of the Upper Goodrich meadow the 50 m data is likely more appropriate for assessing birds actually in the meadow. As a headwater meadow, in a relatively dry watershed with little catchment area above it is unlikely to ever support a riparian meadow bird community, thus its potential to support the wet meadow focal species is likely limited. Thus, it is suggested that other meadow targets such as soil health, hydrology, and vegetation as high priorities than meadow birds at this site.
A total of 17 species within 100 meters of the point count center were detected within the Greenville Creek project area. Wet meadow focal species detected included: 8 Wilson’s Snipe, and 12 Sandhill Crane – all post-restoration implementation. The most frequently detected species were: Horned Lark, Savannah Sparrow, Killdeer, Sandhill Crane, and Wilson’s Snipe. Due to the distance to the nearest forest edge (170 m), all detections within 100 meters at Greenville Creek were birds using the meadow. We found a strong increase in overall bird richness in the project area from pre- to post-restoration. The changes in the avian community from pre- to post-restoration are indicative of a change from a dry grassland condition to a wet meadow. Species that increased the most post-restoration include Sandhill Crane, Wilson’s Snipe, Killdeer, and Red-winged Blackbird – all wetland associates. The species that increased the most, though, was Savannah Sparrow. The increase in soil moisture and reduction in grazing has increased herbaceous understory cover which this species is strongly associated with. In, wetter settings, Savannah Sparrow have been found to decline dramatically as sedges proliferate and standing water on the floodplain surface holds into late spring. But, with the drier overall site condition at Greenville, it is likely that it will never become too wet for Savanah Sparrow. While, the increase in avian richness is impressive, it still is below average for healthy riparian meadows in the area and lacks many of the meadow focal species, which is to be expected 3 years post-restoration. Planted willows at the site have reached 2-3 feet in height and in the next 5 years it is expected more willow associated meadow birds will colonize the site, if this trend in willow growth and cover continues. Management actions that continue to promote a recovery of the vegetative community (herbaceous and woody) will be important to realizing its full potential as meadow bird habitat. It is recommend that avian monitoring of the site be continued every few years to fully evaluate restoration benefits for meadow birds at the Greenville Creek site, and help guide a data driven adaptive management approach.
Greenhouse Gas Research Results
Net greenhouse gas emissions and sequestration were quantitatively investigated in five meadows for this project, including the two restored meadows, Greenville Creek and Upper Goodrich, the un-restored control meadow, East Creek, and two prior restored meadows, Red Clover McReynolds (2006) and upper Clarks Creek (2001). The hypothesis that re-establishing the hydrologic channel/floodplain connectivity increases net carbon sequestration was not consistent among the meadows investigated. Significant increases in soil C stocks were detected at the Greenville Creek project site, but not at the Upper Goodrich project site. Based on the research results more fully described below, it is surmised that increases in soil C stocks are driven by increases in belowground inputs from vegetation. This correlates with the significant increases in soil C stocks found at Greenville, but not Goodrich, in the top 45 cm soil. Greenville had a substantial increase in vegetation biomass (400%), while response to restoration relative to the increase in biomass at the unrestored control site was not as significant (175% for Goodrich, 60% for the control).
GHG Research Objective Outcomes
1) 50% increase in sequestered soil carbon within two years.
Soil C stocks: The unrestored control site (East Creek) showed no significant change between 2015/2016 and 2018 in soil C stocks from 0-15 cm, 15-30 cm or 30-45 cm depths (P > 0.1). After accounting for interannual variability, soil C stocks in the restored site Goodrich increased significantly from the 15-30 cm depth (P = 0.04), but not at the 0-15 or 30-45 cm depths (P > 0.1). Soil C stocks in Greenville were significantly higher at all three depths following restoration, when accounting for interannual variability (P
2) Net GHG fluxes either contribute to, or reduce, the carbon sink strength of restored meadows, depending on methane and nitrous oxide production or consumption. GHG fluxes: Prior to restoration, soil GHG fluxes were dominated by soil CO2 efflux, which accounted for 99% of the annual GHG forcing of the three gases. Cumulative annual pre-restoration soil CO2 efflux was 28-32 Mg CO2 ha-1 y-1. Soil CH4 fluxes were negative (-0.3 - -2 kg ha-1 y-1), indicating net consumption of CH4 by methanotrophic soil bacteria. There was low net N2O soil efflux. After restoration, soil GHG fluxes were still dominated by soil CO2 efflux (~99%) and cumulative annual soil CO2 efflux varied from 26-48 Mg CO2 ha-1 y-1. Post-restoration cumulative annual soil CH4 fluxes were negative at East Creek and Goodrich meadows, but became slightly positive at Greenville (8 kg CH4 ha-1 y-1) yet still only accounted for
Assessing soil C change prior to restoration in thirteen Sierra Nevada meadows.
As part of the SMRRP research, the UNR Soil Ecology Lab identified a need to determine what annual net soil C fluxes were prior to restoration. Therefore, we performed a 13C pulse-chase experiment, in conjunction with the data collected as part of the project partnership, designed to address this knowledge gap. This study has been written as a peer-reviewed manuscript and has been in review at the journal Ecosystems since November 2019. The study demonstrated that 10 of the 13 meadows were strong net C sources to the atmosphere, but three were strong net C sinks. The study highlights the need to maintain meadows that are net C sinks in the Sierra Nevada and the potential for soil C sequestration.
Measuring changes in ecosystem C and N stocks and changes in soil C chemistry across a 20-year chronosequence of time since restoration.
Plumas Corporation has been restoring meadows in the Plumas and Lassen county areas for over 20 years. We took advantage of the fact that several of these sites occur in the same region to develop a space-for-time substation in which we measured C and N stocks and soil chemistry in sites that have been restored at different times. In addition, we identified unrestored “control” sites near the restored meadows to understand how relative changes occur through time. This chronosequence approach allowed us to quantify both permanence of C sequestration due to meadow restoration and the net C sequestration over decadal time scales. This study is being developed for submission to the peer-reviewed journal Ecological Applications in Spring 2020.
Assessing how soil C stocks change among vegetation communities in meadows.
The three projects above focused on the area of the meadow most likely to be influenced by restoration, but we recognized that the C stocks in a meadow are likely to vary in association with plant community composition. We expected that plant community composition would reflect hydrological, geomorphic, and biogeochemical characteristics of the ecosystem that would also influence the net C balance of these sites, with impacts on C stocks. We assessed C stocks in a series of vegetation communities from the meadow center to the surrounding forest edge in seven meadows in the Sierra Nevada. This study is in draft form and we plan to submit it to the peer reviewed journal Plant & Soil in Spring 2020.
Performing laboratory-based studies to determine the mechanisms behind soil C stabilization and sequestration.
We performed two laboratory-based studies to better understand the stability of meadow soil C: A study in which soils were exposed to different temperatures, and a study designed to understand if meadow parent material influenced the mineralization of carbon while soils were wet. The first study was motivated by a desire to understand if soil temperature would influence meadow C sequestration, and in particular, to understand if temperature sensitivity would change as a function of time since restoration. We expected that soil C chemistry would change as a result of restoration, and that in sites that have been restored longer the soil C would be more sensitive to changes in temperature. We performed a lab incubation study in which meadow soils from 1 to 15 years post-restoration were exposed to a range of temperatures between 5 and 40 C. The incubation lasted 145 h, and we measured changes in temperature sensitivity over the course of the incubation. This study is in development for submission to the peer-reviewed journal Soil Science Society of America Journal. Meadow soils were sensitive to temperature, but there was no consistent linear pattern in temperature sensitivity (as expressed by a Q10 value) among sites with increasing age since restoration. This study demonstrates that while meadow soils are sensitive to temperature, the temperature sensitivity of meadow soil does not change with time since restoration. Therefore, we can expect that meadow soil C that has been exposed to restoration for a long period of time is not any more vulnerable to increases in soil temperature than meadow soil C that has only recently been restored. Temperature changes are unlikely to influence the permanence of soil C.
The second study was motivated by observations that meadow soil CO2 efflux rates remained extremely high (>10 umols m-2 s-1) despite fully saturated, standing water conditions early in the growing season. It surprised us that an oxidative process like respiration could continue in the presence of reducing conditions. Other research has suggested that CO2 can be produced in reducing conditions when iron (Fe)-oxidizing bacteria utilize Fe as an alternative electron acceptor and dissolved organic C as their C source. However, Fe concentrations in soil often vary as a function of parent material. Knowing that the Sierra Nevada have both basaltic and granitic meadows, we decided to test if CO2 production in saturated soils varied as a function of basaltic and granitic meadows. We identified two basalt and two granite-derived meadows, sampled soil from each, and wetted the soil between 50% and 200% of water holding capacity. Interestingly, we did not find clear evidence that Fe was more abundant or available in basalt than granitic soils. In three of the four sites, increasing water holding capacity was coupled with an increase in the microbial reduction of Fe(III) to Fe(II). One granitic site had no increase in Fe(II) as a fraction of soil total Fe. However, the two basalt-derived soils, which both had high rates of Fe(II) reduction at high water holding capacity, had both the highest and the lowest rate of soil CO2 efflux at 200% water holding capacity, showing that the production of Fe(II) is not necessarily coupled to the mineralization of C at high soil water contents. We considered if this difference was caused by differences in the abundance or activity of Fe-reducing bacteria in the soil. We blasted 16S sequences from our soils against known Fe-reducers, and demonstrated that we had roughly 20% of known Fe-reducers in our soils. Oddly, the number of known Fe-reducers at our sites was highest in the granitic meadows, rather than the basaltic meadows. The basalt meadows had similar size and composition of and the composition of the Fe-reducing microbial community. Then, we swapped the microbial community between the two basalt-derived soils, and measured rates of CO2 production at 200% water holding capacity. We filtered the microbial community out of the soil, autoclaved soil, then added back the filtered microbial communities such that “home” microbial communities were added to their “home” soil and to “away” soil. Importantly, the microbial community itself did not alter soil CO2 efflux. Rather, the soil itself controlled soil CO2 efflux whether “home” or “away” microbes were added to the soil. This research suggests that the effect of Fe(III) reduction on C mineralization at high water contents alone cannot explain the pattern of high C mineralization we observed in situ in meadow soils. Other soil chemical characteristics may be important to C mineralization, and the composition and size of the microbial community has less of a role in ecosystem function than we expected. This study is in development for submission to a peer reviewed journal.
Additions to the body of knowledge for GHG reduction in mountain meadows, new questions that have arisen, and further work that would naturally progress.
Prior to this work, the state of knowledge of C in mountain meadows was that there was substantial soil C in meadows (Norton et al. 2011, 2014), and that soil GHG fluxes could be high (Blankinship et al. 2014). This project has substantially advanced the state of the science surrounding meadow C cycling by quantifying the impacts of restoration on soil C cycling in two meadows (Greenville and Goodrich), by estimating pre-restoration annual C fluxes in montane meadows, by estimating C sequestration during the first 20 y of meadow restoration, by estimating C stocks in different meadow vegetation communities, and by exploring the mechanisms associated with C stabilization and sequestration in meadows.
We have identified several important knowledge gaps that remain to be answered. We are actively addressing these knowledge gaps. The UNR Soil Ecology Lab is developing a biogeochemical model that is coupled with high resolution remotely sensed imagery and a proprietary map of actual and potential meadow area in the Sierra Nevada to determine how meadow C fluxes have changed over thirty years. This product will allow a land manager to look up the net C balance of a meadow over the last thirty years to determine where to prioritize restoration. This product is in development with funding from NASA via the Nevada EPSCoR funding stream, and we expect the initial products of this model development to be available by the end of 2020. We anticipate validating this model using measurements of net C flux across a new meadow restoration chronosequence we are establishing in the Upper Truckee Watershed in the Tahoe Basin in collaboration with the California Tahoe Conservancy. Our collaboration with the Tahoe Conservancy is funded by the Department of Fish and Wildlife, but this work is part of their match contribution to the project.
Ecosystem C is not sequestered in isolation from other elements. In order for plants and soil to sequester substantial C, other nutrients, such as nitrogen and phosphorus, are required to sustain vegetative productivity and soil microbial activity. One result of the chronosequence research from this study demonstrates that C sequestration appears to increase commensurately with increases in soil N, suggesting that N may limit soil C accumulation. The Soil Ecology Lab has funding from the US Department of Agriculture to understand how N is cycled in meadow soils and how this may limit C sequestration. This work is being carried out in the Sagehen Creek Field Station meadow, where there is a long-term meadow fertilization plot and eddy covariance towers that we can couple our measurements with.
Not all meadow restoration converts the ecosystem from dry soil conditions to wet soil conditions. In many places, meadows have been dammed which caused a change in the soil C cycling. In collaboration with the South Yuba River Citizens League, and with funding from the Department of Fish and Wildlife, the UNR Soil Ecology Lab will begin measuring the impact of dam removal on meadow C cycling in 2020. This work will inform how a different mode of meadow restoration impacts C sequestration.
We hope to better understand the microbial controls on C cycling in meadow ecosystems in the future. Sullivan, the PI of the UNR Soil Ecology Lab, anticipates leading a proposal to the National Science Foundation in 2020 or 2021 to seek funding to explore microbial controls on soil C cycling.