Rogue River Mile 128 Riparian Restoration Annual Monitoring Report

Transcription

1 Rogue River Mile 128 Riparian Restoration Annual Monitoring Report November 2012 December 2013 (Project Year 01) Date Submitted: March 31, 2014 PROJECT INFORMATION Project Name Rogue River Mile 128 ECP Project # 133 SERVICE AREA Watershed (USGS HUC 4) Middle Rogue ( ) Ecoregion Klamath Mountains (Level III Ecoregion) Other Rogue River/Snyder Creek HUC 5 ( ) PROJECT LOCATION Latitude/Longitude / Area (acres/hectares) Linear Feet of Stream 3.40 acres 1,637 ft PROJECT DEVELOPER Organization Contact person Title Phone/ The Freshwater Trust Christy Meyer Ecosystem Services Coordinator /Christy@thefreshwatertrust.org

2 PROJECT OVERVIEW The Freshwater Trust s riparian revegetation project described in this report is located in Jackson County, southwest Oregon, on the south bank of the Rogue River mainstem about 128 miles upstream from its mouth at the Pacific Ocean. The Rogue River supports the largest wild fish population of any of Oregon s coastal rivers, including sensitive salmonids. The Rogue River has been the target of many dam removal campaigns, and fish passage has been improved since most of the dams below Lost Creek Lake (about 30 miles upstream of the project) have been removed or modified. Parts of the river have been designated Wild and Scenic, and Coho, spring and fall Chinook, and summer and winter steelhead all migrate past the project site. Local black bears are known to use the site to forage on salmon carcasses during runs. The goal of The Freshwater Trust s riparian revegetation project along the Rogue River is multifold. The desired future condition is an ecologically functioning riparian forest that will improve structural and species diversity, replace invasive species cover with native cover, provide shade to the stream, stabilize eroding banks and provide a future source for wood recruitment. Riparian plantings will also generate compliance-grade water temperature credits. Using Oregon Department of Environmental Quality s Shade-a-lator model version 8, The Freshwater Trust calculated uplift (shade credits) at the Rogue river mile (RM) 128 site to be 69,073,622 kilocalories per day. This credit calculation was conducted for October 16th, using projected tree heights at maturity. These shade credits were generated upon third party verification of the site and have been sold to the City of Medford to offset the temperature effluent limit requirements of its NPDES permit. Maintaining the shade credits generated by this project, and the ecological value they represent, is dependent on third party verification over a 20-year period (through 2033). To increase long-term riparian ecological functionality and meet performance standards, stewardship of the project s plantings is of primary concern for The Freshwater Trust. This document summarizes monitoring results and site performance at the end of the first year after planting. PERFORMANCE SUMMARY Riparian revegetation efforts at the Rogue RM 128 site have been successful thus far, and the site now supports a very high diversity of native trees and shrubs that will contribute to riparian ecological function and stream health into the future. Much of the establishment success and growth observed at this site can likely be attributed to consistent irrigation, site maintenance and suppression of competitive plant species. The site is well on track to meet native woody plant density requirements, despite the challenges of a very hot and dry summer. Although several invasive weed species are present, frequent maintenance efforts have kept cover at an average of only 6.3%. Maintenance efforts to control invasive species are ongoing. The site sustains many native herbaceous species, which contribute to beneficial ecological functions. 2

3 DATA SYNTHESIS COMPARED TO RIPARIAN REVEGETATION PERFORMANCE STANDARDS Twelve randomly established plots (total area=0.6 acres; see Appendix A for site map) were surveyed to provide the following estimates of each metric for the total planting area (total area=3.4 acres) 1 : METRIC SURVEY ESTIMATES MEETS YEAR 5 PERFORMANCE STANDARD 2 A. native woody stem density 2,617 stems/acre B. proportion native tree stems 48.1% of total stems C. proportion native shrub and vine stems 51.9% of total stems D. number of native woody species 11 trees +14 shrubs +2 vine = 27 total E. percent cover of invasive 3 woody species 5.5% cover F. percent cover of invasive 4 herbaceous species 0.8% cover A. Native woody stem density was estimated from counts of all native tree, shrub and woody vine stems in plots. The average stem density across plots was 2,617 stems/acre (SE = 442). Based on our sample data, we are 80% confident that the project area stem density per acre is between 2,014 and 3,220 (tfactor=1.363). This exceeds the desired year 5 target of 1,600 stems/acre. Nearly half of the stems counted in plots were thought to have pre-existed plantings, including scattered mature trees but also native woody vines and resprouting or naturally recruiting tree or shrub seedlings. B. The average proportion of native stems that were trees was 48.1% (SE = 5.1%). Based on our sample data, we are 80% confident that the project area proportion of tree stems is between 41.1% and 55.0% (t-factor=1.363). This meets the desired year 5 target of minimum 20% native tree stems (or, maximum 80% native shrub and vine stems). C. The average proportion of native stems that were shrubs was 49.8% (SE = 5.2%), and the average proportion that were vines was 2.1% (SE = 2.0%), for a combined proportion of 51.9%. Based on our sample data, we are 80% confident that the project area proportion of shrub and vine stems is between 46.0% and 58.9% (t-factor=1.363). This meets the desired year 5 target of minimum 20% native shrub and vine stems (or, maximum 80% native tree stems). D. The Rogue 128 planting area was quite diverse, and supported 11 native tree species, 14 native shrub species and 2 native vine species. Four of these species appeared to pre-exist plantings (Table 1). This total count of 27 native woody species exceeds the desired year 5 target of minimum five native woody species. Three non-native tree species were also present on site; these are noted in Table 1, below. On average, black cottonwood and sandbar willow stems were the most common, followed by Oregon ash (Table 1). About half of the cottonwood stems and nearly three-quarters of the ash appeared to pre- 1 Detailed sampling design and methods are described in The Freshwater Trust Revegetation Monitoring Protocol for Water Quality Trading Projects. 2 As described in: Willamette Partnership Draft General Crediting Protocol Addendum: Riparian Planting Standards. 3 Invasive species are those defined by the Oregon Department of Agriculture Noxious Weed list, plus those defined as problematic by The Freshwater Trust s riparian plant experts. 3

4 exist plantings; most of these stems were naturally-recruiting seedlings or saplings that were resprouting, probably in response to site mowing to control Himalayan blackberry. All of the sandbar willow stems were from plants on the site prior to revegetation efforts. No single species comprised over 50% of all native woody stems, which meets the desired year 5 target. Table 1. Native woody species diversity and composition in September 2013 (Year 1). Scientific Name Common Name Nativity a Avg % Stems Yr 1 Acer macrophyllum bigleaf maple N 5.9 Alnus rhombifolia white alder N 0.7 Alnus rubra red alder N 1.8 Amelanchier alnifolia Saskatoon serviceberry N 0.9 Calocedrus decurrens incense cedar N 3.7 Cornus sericea redosier dogwood N 3.6 Corylus cornuta California hazelnut N 0.2 Crataegus douglasii black hawthorn N 1.3 Crataegus monogyna b one seed hawthorn I 0.2 Fraxinus latifolia Oregon ash N 7.8 Holodiscus discolor oceanspray N 1.1 Malus fusca Pacific crab apple N 0.9 Philadelphus lewisii mock orange N 2.3 Physocarpus capitatus Pacific ninebark N 2.9 Pinus ponderosa ponderosa pine N 6.7 Platanus occidentalis b American sycamore I 0.2 Populus trichocarpa black cottonwood N 19.9 Prunus virginiana western chokecherry N 3.0 Quercus kelloggii California black oak N 1.0 Ribes divaricatum b spreading gooseberry N 0.2 Ribes sanguineum red flowering current N 0.3 Robinia psuedoacacia b black locust I 0.2 Rosa nutkana Nootka rose N 1.1 Rubus ursinus b trailing blackberry N 1.1 Salix exigua b sandbar willow N 19.6 Salix sp. b willow (sp. unknown) N 0.8 Sambucus mexicana blue elderberry N 0.7 Spiraea douglasii Douglas spirea N 4.2 Symphoricarpos albus common snowberry N 5.4 Unknown unknown woody N 0.2 Vitis californica b California wild grape N 2.2 TOTAL a N = native, I = introduced. b All stems appeared to pre-exist plantings. At the end of the first year after installation, the largest proportion (47.4%) of planted native woody stems was 1 ft to 3 ft tall, although 9.0% had already grown to 5 ft to 7 ft tall and 10 stems of planted 4

5 black cottonwood and blue elderberry had already achieved heights over 7 ft. Some blue elderberry had already flowered and fruited, providing important resources for pollinators and other wildlife. Photo point monitoring within the site also illustrated excellent tree and shrub growth (see Appendix B, Photo Point Monitoring). Both deer and jackrabbit scat was common within the planting area, and several jackrabbits were seen during monitoring. Browse was observed on 8.6% of live native woody stems in plots, but browse impact was generally minor. Browse most often targeted red flowering current and red alder, though many stems of serviceberry, chokecherry, Pacific ninebark, and bigleaf maple were also browsed (Table 2). Only 3.8% of stems were seen to be unhealthy or dying from browse or any other cause, although vigor varied by species (Table 2). Table 2. Browse and vigor by species. % Unhealthy % Browsed Scientific Name Common Name or Dying Acer macrophyllum bigleaf maple Alnus rhombifolia white alder Alnus rubra red alder Amelanchier alnifolia Saskatoon serviceberry Calocedrus decurrens incense cedar Cornus sericea redosier dogwood Corylus cornuta California hazelnut Crataegus douglasii black hawthorn Crataegus monogyna one seed hawthorn Fraxinus latifolia Oregon ash Holodiscus discolor oceanspray Malus fusca Pacific crab apple Philadelphus lewisii mock orange Physocarpus capitatus Pacific ninebark Pinus ponderosa ponderosa pine Platanus occidentalis American sycamore Populus trichocarpa black cottonwood Prunus virginiana western chokecherry Quercus kelloggii California black oak Ribes divaricatum spreading gooseberry Ribes sanguineum red flowering current Robinia psuedoacacia black locust Rosa nutkana Nootka rose Rubus ursinus trailing blackberry Salix exigua sandbar willow Sambucus mexicana blue elderberry Spiraea douglasii Douglas spirea Symphoricarpos albus common snowberry Vitis californica California wild grape

6 E. Herbaceous species cover and invasive woody species cover were estimated from two subplots placed randomly within each hydrological zone of each plot. The average cover of invasive woody species across plots was 5.5% (SE = 1.9%). Himalayan blackberry (Rubus bifrons) was the only invasive woody species observed in plots (Table 3). Based on our sample data, we are 80% confident that the project area invasive woody species cover is between 2.9% and 8.1% (t-factor=1.363). This meets the desired year 5 target of less than 10% invasive woody cover. Although not a listed noxious weed, the black locust trees on site are of concern because they were found to be recruiting. One seed hawthorn was another non-native tree present on site that is known to be weedy. Trees, saplings and seedlings of these and the non-native American sycamore trees should be closely monitored and possibly removed from the site. F. The cover of invasive herbaceous species across plots was variable (range 0.0% to 4.3%), but averaged 0.8% (SE = 0.3%). The most common observed invasive species at the end of Year 1 was poison hemlock (Conium maculatum; Table 2); this species was germinating occasionally under overhead irrigation sprinklers. Other noxious weeds including St. John s wort (Hypericum perforatum), bull thistle (Cirsium vulgare), puncturevine (Tribulus terrestris) and reed canary grass (Phalaris arundinacea) were also present in trace amounts but were not captured in plots. Based on our sample data, we are 80% confident that the project area invasive herbaceous species cover is between 0.3% and 1.2% (tfactor=1.363). This meets the desired year 5 target of less than 20% invasive herbaceous cover. Table 3. Mean percent cover of invasive woody and herbaceous species. Scientific Name Common Name Avg % Cover Yr 1 Rubus bifrons a Himalayan blackberry 5.5 TOTAL INVASIVE WOODY COVER 5.5 Centaurea solstitialis a yellow starthistle 0.2 Conium maculatum a poison hemlock 0.5 Phalaris arundinacea reed canarygrass 0.02 Taeniatherum caput-medusae a medusahead 0.04 TOTAL INVASIVE HERBACEOUS COVER 0.8 a ODA-listed noxious species. At the end of the first year after planting, much of the ground was unvegetated, and a mulch of Himalayan blackberry canes resulting from initial site treatment was prevalent. Nonnative, noninvasive herbaceous cover averaged only 2.6% (SE = 1.3%); non-native bladder campion (Silene latifolia) and soapwort (Saponaria officinalis) were fairly frequent. In plots, native herbaceous cover was only 0.3% (SE = 0.1%) at the end of the first growing season. Although native herb cover was generally low, the site supported many native forb species that pre-existed the planting project or were naturally recruiting, including mugwort (Artemisia douglasiana), showy tarweed (Madia elegans), lotus (Lotus sp.), California poppy (Eschscholzia californica), stream orchid (Epipactis gigantea), willowherb (Epilobium sp.) and blue wildrye (Elymus glaucus). These natives greatly increase site biodiversity and provide native pollinator and other habitat. Site management will be designed to encourage them. 6

7 SITE HISTORY AND MAINTENANCE ACTIONS The Rogue RM 128 site currently supports one residence, but was previously mined for gravel; gravel mining is now restricted to areas above the 100-year floodplain. Both the residence and the gravel mining are well inland of the planting area. The project site consists mainly of a flat flood terrace (overbank hydrological zone) bordered on the inland side by a manmade slope or levee (transition and upland hydrological zones) designed to separate the active river channel from the historical gravel mining pit/pond. An unpaved access road runs along the top of the levee. Small portions of the flood terrace in the upstream project section (Appendix A) support a low-lying, seasonally inundated swale or wetland and alcove. Site conditions prior to the implementation of the revegetation project were mainly the result of high water events in combination with the landowner s modifications to mitigate risk from overbank flows. Modifications to the river s channel in the several miles above and below the project site, as well as increased urbanization and land clearing within the greater watershed above this project, have resulted in the potential for high volume pulses of water associated with storm systems. In 1997, a year flood event caused significant changes to the river s course and banks in this reach. After 1997, actions taken by the landowner substantially reduced the risks associated with high water events. Some of these actions included installing rock fins along some vulnerable bank areas to deflect scouring flows, grading and stepping back the banks to resist erosion and provide a more natural spreading of high flows, and placing durable fill in the upper end of the project site to prevent under cutting of bank areas that receive high velocity flow. These management activities have stabilized the site, but the vegetation community on site reverted to mostly invasive species following the disturbance caused by the 1997 flood. Prior to site preparation, much of the planting area was dominated by dense cover of Himalayan blackberry, and lacked substantial native vegetation as a result of historic land use, disturbance from past floods and suppression by well-established invasive species. Noxious weeds including yellow star thistle, puncturevine, and medusahead were occasional along the roadway running along the levee, and poison hemlock was found in portions of the flood terrace area with particularly wet soils. Some areas of the site nearest the river, however, supported some mature black cottonwoods, white alder and Oregon ash trees, along with sandbar willow immediately adjacent to the river and occasional shrubs of common snowberry and spreading gooseberry on the floodplain, with some native trailing blackberry and California wild grape vines. Along with these native species, a few non-native, mature trees were present on the site prior to the project, including American sycamore, black locust and one seed hawthorn. The landowner planted a few Oregon ash several years prior to the The Feshwater Trust s project in areas inland of our planting site. The revegetation project was implemented in two phases, as a way of avoiding the fall clearing of areas expected to be subjected to annual inundation and erosion from high winter flows. The first phase (downstream portion of the project; Appendix A) was cleared of Himalayan blackberry with an excavator, and planted in November of The second phase (upstream portion) was cleared and planted in June of 2013, after the threat of high water events had passed. To discourage river users from coming onto the property, a buffer strip approximately 5-30 ft wide of sandbar willow and Himalayan blackberry was retained alongside the river. In the immediate future, Himalayan blackberry will be controlled within this strip as needed to prevent expansion into the planting area, but blackberry will eventually be replaced by native willow and alder once a visual screen has been achieved through growth of the plantings. 7

8 A diverse mix of native trees and shrubs were installed at a high density (2,000 stems per acre) with the goal of achieving 100% ground shading by project year three to help retard invasive plant species recolonization of the site. The plantings were extended beyond the area the 60-ft buffer that generally generates most of the shade credits as a measure to suppress invasive species recolonization, and because the hydrology and land form of the site suggested that a riparian forest would have likely occupied a wider area historically. Regrowth of invasive species will be controlled with spray and hand methods for a minimum of three years, or until plantings reach a free to grow state. The greatest threat to this project s success, however, is expected to come from high water events. In the upstream portion of the planting area, overhead irrigation was installed on the flood terrace, but drip irrigation was used on the levee slope. Drip irrigation was installed in all parts of the downstream portion of the planting area. All plants with drip irrigation were also mulched with squares of black plastic, and plants with overhead irrigation were mulched with bark. Vexar tree tubes were installed around nearly all plants in the open (i.e., those with drip irrigation) for browse protection, except plants in areas likely to be inundated by high flows. Since plantings, site maintenance has been guided by frequent visits by the project manager and The Freshwater Trust s contractor. Site maintenance needs are expected to be greatest in years 1 and 2 and should taper off to a bi-weekly or monthly visit by year 3. The summer of 2013 was particularly hot and dry. Irrigation began in early May and lasted through mid October. Scattered mature trees provided some cover to plants on the floodplain, but plants on the slope were in full sun and far from the water table. In general, contractors were scheduled to water the site every other day when temperatures exceeded 90 degrees F, and watered at longer intervals in cooler weather. Watering averaged once per week over the summer, but twice per week during hotter periods. Each plant generally received 2 gallons per hour for 3-4 hours, for an average of 6-8 gallons per week during the irrigation season, as consistent with The Freshwater Trust s approved limited use license. Although crucial for plant survival, irrigation may increase maintenance needs. Overhead irrigation appeared to be contributing to poison hemlock seed germination in the lower sections of the project closer to the water. In portions of the site where drip irrigation was installed, expansion and contraction of irrigation lines sometimes moved emitters away from plant bases, misdirecting water. Placing emitters under plastic mulch mats may be preferable for future installations. Small amounts of peletized chicken manure was applied once at planting, and once in July, to improve growth and vigor of plantings. No fertilization is expected to occur beyond year 3. Herbicide applied with a backpack sprayer targeted Himalayan blackberry throughout the site, and reed canary grass and other competitive grasses and poison hemlock in the floodplain terrace. Aquaneat (glyphosate) herbicide with no spreader/surfactant/adjuvant was applied twice, once in the spring and then once in the summer or fall, depending on which portion of the site was targeted. Weed whacking and hand pulling occurred as needed, usually once a week, concurrent with irrigation. Dead plants were replaced in fall of 2013, and new plantings will be included in next year s monitoring results. 8

9 Appendix A Site Map with Monitoring Locations 9

10 Rogue RM128 Revegetation and Photo Point Monitoring Locations RogCPT RogCPT08 RogCPT RogCPT10 Flow RogCPT05_2 RogCPT04_ RogCPT02_2 RogCPT03_ P2_P1 RogCPT06_2 RogCPT01_2 Photo Point Monitoring Locations Phase I As Built Phase II As Built Revegetation Macroplot Origins: Phase I Points Phase II Points Feet 1 inch equals 250 feet Date: 3/11/2014 K Coordinate System: NAD 1983 Oregon Statewide Lambert Projection: Lambert Conformal ConicNorth American 1983

11 Appendix B - Selected Photo Point Monitoring Results Images depict conditions prior to planting and at the end of year 1 after planting. 11