Vegetation Communities or Land Surface without Rarity Ranking Asphalt: Road segments greater than approximately 4 m2 that were covered in asphalt were included in this category. No other areas outside of the road bed were present. This land cover class is proposed for removal throughout the project area.
Open Sand: Vast unvegetated parabolic dunes, transverse dunes, sand sheets, and deflation plains where vegetation, typically dune matt and EBG, was less than approximately 5% total cover comprised this cover class.
European beach grass swards: Ammophila arenaria (European beach grass swards) Semi-natural Stands
This class includes vegetation where EBGhad the dominant relative cover in herbaceous layer. Few other plant species grew in stands that have not been previously treated with herbicide; however, in previously treated stands, EBGgrew with cudweed (Gnaphalium stramineum, G. palustris), dune sage, yellow sand-verbena, beach bur, and popcorn flower (Plagiobothrys sp.).
European beach grass occurs through the Ten Mile dune system and herbicide treatment is planned for the treatment, with the goal of eventually eradicating it from the Preserve. This nonnative grass stabilizes the dunes and alters the geomorphology of dunes, especially the foredunes where it nearly eliminates nesting habitat for the western snowy plover. The removal of this weed through this project will result in a net gain of dune mat vegetation. (See “Project Description” for more information on treatment of EBG.)
Cudweed(Gnaphalium spp.): This vegetation assemblage did not fall under vegetation alliances described in the MCV, nor did it have a significant component of dune mat to be classified as such. This vegetation was restricted to the dead stands of EBG that were treated with herbicide over the past several years. The vegetation was primarily comprised of dead EBG, everlasting cudweed (Gnaphalium stramineum) and marsh cudweed (Gnaphalium palustre) and occasional Australian fireweed (Erechtites minima) and sow thistle (Sonchus oleraceus).
This vegetation community often colonizes those areas where dead EBG occurs and eventually succeeds to dune mat. No impacts will occur to this community.
Common velvet grass - sweet vernal grass meadows(Holcus lanatus - Anthoxanthum odoratum): Two meadows of velvet grass and sweet vernal grass occur near the project area. These types meadows have usually had some level of grazing in the past and they often succeeding to shrubs and conifers. This vegetation community is not sensitive and no impacts will occur.
Eucalyptus groves (Eucalyptus globulus): A large stand of eucalyptus occurs on the eastern edge of the northernmost dune lobe, mostly on private property. Eucalyptus saplings may be removed on the western edge of the stand but no treatment to the mature trees is proposed. A small patch of EBG occurs adjacent to the stand, but EBG treatment will not occur outside the EBG boundary. No impact to this plant community.
Three-square bulrush marsh(Schoenoplectus pungens): No recognized vegetation association has been assigned to stands of three-square bulrush (Schoenoplectus pungens) in the MCV (XX); however it can be characterized by the Holland classification of “Coastal Brackish Marsh” (CDFG 2010). It forms nearly monodominant stands in small brackish marshes in MacKerricher State Park and likely throughout the coastal region of Mendocino County. Sizes of bulrush stands fluctuate with during drying events and flooding, both tidal and stream. Growing in shallow waters, they help trap and bind mucky sediment in coastal marshes.
Some temporary impacts to this community may occur during the removal of culverts. Transplanting as mitigation is proposed.
Small-fruited bulrush marsh(Scirpus microcarpus): This vegetation is closely associated with the three-square bulrush, but is less tolerant of saltwater and is usually found in freshwater marshes. Only one small stand of this vegetation occurs on north bank of Inglenook Cr. downstream of the culvert. No impacts are anticipated. Culvert removal will allow for greater upstream stormwater surges and potentially increase this plant community.
Slough sedge swards(Carex obnupta): Slough sedge is the dominant plant of the freshwater marsh upstream of the culvert in Fen Cr. A small patch occurs near the culvert outlet where brackish water is probably limited. No impacts are anticipated.
Pacific silverweed marshes (Argentina egedii): Pacific silverweed occurs in the Fen Cr. marsh where it comprises part of the wetland vegetation. It is codominant with slough sedge, Pacific oenanthe, and wild mint in the freshwater marsh upstream of the culvert and codominant with three-square bulrush in the brackish area of the marsh, downstream of the culvert.
Some temporary impacts may occur during culvert removal; however the removal will increase habitat for the plant community.
Salt rush swales (Juncus lescurii): This vegetation community is typically located in stabilized dune hollows and swales regularly flooded or close enough to the water table to support hydrophytic vegetation. Where the dune swales are more stabilized, vegetation succession tends towards sparse stands of coyote brush (Baccharis pilularis) and wax-myrtle (Myrica californica) intermixed with salt rush. A comparison of aerial photographs shows that this vegetation community has become increasingly established east of the foredunes over the past 50 years or more.
The rush that comprises this vegetation community was keyed as J. lescurii; however MCV describes its ecology as occupying the upper edge of salt marshes, while J. breweri occupies dune swales. This difference in ecology may be from a misidentification of J. lescurii in other dune and marshes of California or it may reflect a different ecological niche in coastal Mendocino County.
These rush swales are located inland of the haul road and no impacts are anticipated.
Horsetail(Equisetumhyemale ssp. affine): No recognized vegetation association has been assigned to stands E. hyemale ssp. affine. However, for the purposes of assigning a rarity rank, may be considered dune mat with a hydrophytic component. Horsetail is often > 50% relative cover in the herbaceous layer, and codominant with wetland plants like willow and salt rush, and upland plants like dune sage and blue grass. The stands are usually found on the upland edge of willow thickets in watercourses.
Some temporary impacts may occur during the haul road removal, especially near the creeks. However, the removal of the road fill will likely increase habitat.
Sea lyme, or dune grass patches(Leymus mollis): Small stands of dune grass occur on the coastal strand and Ten Mile River estuary. Some of the stands having a greater component of yellow sand verbena and sea rocket were classified as the Leymus mollis - Abronia latifolia - (Cakile sp.) association.
This vegetation community has increased after the removal of EBG. No impact.
Dune mat(Abronia latifolia - Ambrosia chamissonis): Dominant plant species that comprised this vegetation community are dune sage, yellow sand-verbena, beach bur, sand-dune blue grass, and beach morning-glory. This was the most prominent vegetation community throughout the Ten Mile dune system. Dune mat supports several special-status species: Menzies’ wallflower (Erysimum menziesii ssp. m.), Howell’s spineflower (Chorizanthe howellii), round-headed Chinese houses (Collinsia corymbosa), dark-eyed Gilia (Gilia millefoliata), and pink sand-verbena (Abronia umbellata ssp. breviflora). Since EBG has been removed from the foredunes, dune sage, beach bur, and yellow sand-verbena have become established. The removal of EBG has caused sand to become mobile and move landward, where peninsular-like extensions are often colonized by dune sage or beach morning-glory (Figure XX).
Several recognized vegetation alliances were identified and mapped: Ambrosia chamissonis - Abronia latifolia, Abronia latifolia - Ambrosia chamissonis - Cakile maritima, Artemisia pycnocephala - Poa douglasii, and Artemisia pycnocephala - Calystegia soldanella. An assemblage of plants that was part of the dune mat alliance was classified as “Artemisia pycnocephala - roadside weeds.” This assemblage grew on the edge of the haul road in the stabilized soils overlying the rocks used for the railroad ballast. Dominant plants were ripgut brome (Bromus diandrus), burclover (Medicago polymorpha), rattlesnake weed (Daucus carota), stork’s bill (Erodium cicutarium), cat’s ear (Hypochaeris radicata), four-leaved allseed (Polycarpon tetraphyllum), plantain (Plantago lanceolata), six weeks fescue (Vulpia bromoides) and European hairgrass (Aira praecox). This assemblage was mapped separately because it was habitat for spineflower.
The haul road is now covered with sand and dune mat in some areas; few areas of asphalt area are exposed (Fig. XX). Approximately 0.12 acre (300’ x 18’ road) of dune mat covers the road at the bend in the road near the Ten Mile River; approximately 1.2 acres (3000’ x 18’ road) of dune mat covers the road north of Inglenook Creek; and approximately 0.66 acres (1600’ x 18’ road) covers the haul road south of Fen Creek. Approximately XX acres of dune matt will be impacted by the project when sand is removed to allow for heavy equipment and vehicle access to the southern portions of the project area. However, the removal of the asphalt and road base will directly benefit this vegetation community by opening up new habitat in approximately XX acres. Mitigation for impacts, primarily an ongoing plan of invasive weed removal, is included in Appendix XX.
Figure XX. As sand moves on to the haul road, dune plants such as dune sage become established shortly after.
Figure XX. Few areas of asphalt are exposed where sand drifts onto the road and dune mat is subsequently becoming established.
Coastal silk tassel scrub(Garrya elliptica): A large stand of silk tassel mixed with pink-flowering current grows on the dune ridges above a dune swale dominated by bishop pine at the southern end of the Preserve. EBG is proposed for treatment adjacent to the silk tassel; however, no impacts to the silk tassel shrubs would occur following avoidance measures.
Wax myrtle scrub (Morella californica): Wax myrtle often grows among the willow thickets, sometimes as a codominant species, but it grows as a dominant species in rush swales in the southern portion of the Preserve. EBG is proposed for treatment adjacent to the wax myrtle; however, no impacts to the silk tassel shrubs would occur following avoidance measures.
Coastal dune willow thickets (Salix hookeriana): Dune willow stands occur throughout the project area in dune swales and along Fen and Inglenook Creeks. EBG is proposed for treatment adjacent to the dune willow; however, no impacts would occur following avoidance measures. Some dune willow growing up- and downstream of the culverts proposed for removal would be impacted by the removal of the road fill. However, the road berm removal would create new habitat. Revegetation is proposed to mitigate the temporary impacts to the willow.
Sitka willow thickets (Salix sitchensis): Sitka willow, red alder and dune willow are dominant species that comprise the Sitka willow thickets. In the project area, they are found in Inglenook Creek in the swampy vegetation inland from the foredunes. EBG is proposed for treatment adjacent to the dune willow; however, no impacts would occur following avoidance measures.
Beach pine forest (Pinus muricata): A small stand of beach pine occurs on private property more than 100’ from the project area. No impacts to the vegetation will occur.
Bishop pine forest (Pinus muricata): A small stand of bishop pine mixed with tan oak, grand fir, and red-flowering currant grows in a dune swale surrounded by steep dunes. EBG treatment will occur approximately 70’ from the stand; however no impacts to the stand are anticipated because the stand will not be entered.
Wetlands A wetland survey was conducted to locate wetlands that may be under the US Army Corps of Engineer jurisdiction and the California Coastal Commission jurisdiction (Appendix XX). The most common type of wetland in the project area was salt rush swales. These occur on the east side of the haul road and will not be affected by the proposed project. The remaining wetlands were those associated with the two creeks: Inglenook Creek and Fen Creek.
Some short term impacts will occur during the removal of the culverts, but after project completion, there will be a net gain of wetlands. Planting of appropriate native wetland vegetation is proposed as mitigation.
Potential impacts to sensitive species are discussed below.
Invertebrates Globose dune beetle (Coelus globosus) – This flightless burrowing beetle, a nocturnal detritivore, was once common in low beach foredunes from central to southern California as well as Baja California, Mexico. Globose dune beetles and their larvae are associated with Sand Verbena (Abronia maritima), Beach Burr (Ambrosia chamissonis) and Sea Rocket (Cakile maritima) and are typically found within 5-10 cm beneath these plants. The globose dune beetle has been detected on Ten Mile beach. In 1978 the USFWS proposed listing this species and identified the narrow strip of dune habitat on the west side of the haul road between the Ten Mile River and the mouth of Mill Creek as potential critical habitat.
Ten Mile shoulder band snail (Noyo intersessa) – Likely endemic to the Ten Mile dunes, coastal dunes and coastal scrub areas of vegetation provide habitat for this species. Growth, copulation, and egg-laying most likely occur during the rainy season, based on the biology of related snail species. There is documented occurrence of the Ten Mile Shoulder band snail at the south end of Ten Mile beach
Removal of the haul road, redistribution of rock and sand during the project, and establishment of materials storage and equipment staging areas would temporarily alter the habitat of the globose dune beetle and the Ten Mile shoulder band snail in the immediate project area. Upon completion the project has potential to improve habitat for both species by restoring the dunes to a more natural state and encouraging the growth of native vegetation. With the implementation of mitigation measures the Project would have a less than significant impact on the Globose dune beetle and the Ten Mile shoulder band snail.
Vertebrates Fish Chinook Salmon (Onchorhynchus tshawytscha) – California coastal Evolutionarily Significant Unit (ESU) Chinook salmon are listed as a threatened species by the US Fish and Wildlife Service due to habitat loss and modification resulting from logging, dams, water diversions, gravel mining, urbanization, stream channelization, wetland loss, and poor watershed management. Habitat requirements include cool, clear streams with gravel substrate for spawning and shaded pools with large woody debris for resting and hiding. Chinook salmon migrate upstream from June through December with a peak in September and October. While the Ten Mile River watershed to the north of the project area has been designated critical habitat for Chinook salmon and has documented presence, Fen Creek and Inglenook Creek within the Dune Preserve do not provide suitable habitat for Chinook salmon and have not been designated critical habitat by the USFWS. The MacKerricher State Park Dune Rehabilitation Project will have no negative impacts on California coastal ESU Chinook salmon.
Coho Salmon (Oncorhynchus kisutch) – The Central California Coast ESU Coho salmon are designated endangered by the USFWS under the Endangered Species Act and a Species of Special Concern by California Department of Fish and Game due to habitat loss and modifications resulting from logging, dams, water diversions, gravel mining, urbanization, stream channelization, wetland loss, and poor watershed management. The Central California Coast ESU includes all naturally spawned populations from Punta Gorda south to San Lorenzo River and all reaches, including estuaries and tributaries, are designated as critical habitat. The ESU population also includes Coho from four artificial propagation programs, one of which is located south of the project area on the Noyo River. The anadromous Coho often practice natal stream fidelity and return inland to clear-running streams with woody debris and gravel substrate, their required habitat, following heavy late autumn or winter rains to spawn. Coho salmon occur in the Ten Mile River and its tributaries to the north of the project area. Fen Creek and Inglenook Creek, perennial coastal streams located in the project area, do not currently provide suitable habitat for Coho salmon. The MacKerricher State Park Dune Rehabilitation Project will have no negative impacts on Central California Coastal ESU Coho salmon.
Steelhead (Oncorhynchus mykiss irideus) – The Northern California Coastal Steelhead ESU Steelhead, ananadromous form of rainbow trout which may spawn more than once are designated as endangered by the USFWS under the Endangered Species Act due to habitat loss, poor watershed management, overharvest and poaching, disturbance due to human activities, and hatchery practices. The Steelhead ESU includes populations from Redwood Creek in Humboldt County to the Gualala River in Sonoma County. Steelhead return inland between December and April when they seek out holding pools deeper than 3 meters with stream bank cover during migration and require cool, clear, well-oxygenated perennial streams with woody debris and gravel substrate for spawning. Fen Creek and Inglenook Creek, perennial coastal streams located in the project area, do not currently provide suitable habitat for Steelhead Trout. . The MacKerricher State Park Dune Rehabilitation Project will have no negative impacts on Northern California Coastal Steelhead ESU Steelhead.
Tidewater Goby (Eucyclogobius newberryi).
The Tidewater goby is listed as endangered by the USFWS under the Endangered Species Act and as a California Species of Special Concern by DFG due to habitat loss and modification resulting from coastal development, channelization of habitat, diversions of water flows, groundwater over-drafting, and alteration of water flows. The small and benthic Tidewater goby, endemic to California, inhabit brackish coastal waters including lagoons, estuaries, marshes and lower stream reaches where the water is fairly still but not stagnant. Tidewater gobies occur in the Ten Mile River, at the northern boundary of the Dune Preserve, Virgin Creek within MacKerricher State Park, and Pudding Creek on the southern boundary of MacKerricher.
The USFWS conducted surveys at the Inglenook Fen in 2003 but did not detect or capture any Tidewater gobies. Surveys conducted in 2011 failed to detect Tidewater gobies in the estuarine waters of either Inglenook or Fen Creek but did successfully capture individuals in Ten Mile River. While both Inglenook Creek and Fen Creek contain marginally suitable habitat near and downstream of the project area gobies presence is improbable due to the low quality of the habitat. Since it is unlikely that the Tidewater Goby is present and multiple surveys have produced no detections, the Project would have no impact on this species.
Under the direction of USFWS permit holders, trained park staff will survey for Tidewater Goby presence in both Fen and Inglenook Creek at and below the project area 30 days prior to project activity. In the event gobies are detected appropriate mitigation measures would occur under the recommendations of the USFWS. In this case the MacKerricher Dune Rehabilitation Project would have a less than significant impact on Tidewater goby populations after mitigation measures if appropriate.
Amphibians Foothill yellow-legged frog (Rana boylii) – The Foothill yellow-legged frog, a highly aquatic species rarely encountered far from permanent, shallow, flowing water, is considered a California Species of Special Concern by the DFG due threats within their range such as water diversion, water-quality issues associated with logging and livestock grazing, and the introduction of exotic predatory aquatic fauna. It occurs in or near rocky streams in habitats of coastal scrub, wet meadow and valley-foothill riparian. Breeding and egg-laying occur after spring flooding from mid-March to May for approximately two weeks. Eggs hatch after 5 days with tadpoles reaching up to 2.2 inches and metamorphosing in 3 to 4 months. Foothill yellow-legged frogs are highly aquatic and prefer shorelines with extensive vegetation. Habitat used by adult frogs includes patches of dense grassy or shrubby vegetation that maintain substrate moisture, such as willow thickets and dense sedge swales.
The Foothill yellow –legged frog is known to occur within the Coastal Redwood Forest habitat within the Inglenook Fen – Tenmile Dune Nature Preserve historically. Survey for rana boylii prior to project initiation will occur by trained park staff. In the event Foothill yellow-legged frogs are detected within the project area mitigation will be implemented. The MacKerricher Dune Rehabilitation Project will have no negative impact on Foothill yellow-legged frog populations following mitigation measures.
Northern red-legged frog (Rana aurora aurora) – The Northern red-legged frog is considered a California Species of Special Concern by the DFG due to habitat degradation from coastal development, timber harvesting and grazing as well as exotic predatory fishes in many coastal watersheds. The northern red-legged frog inhabits quiet pools of streams, marshes, and occasionally ponds throughout its California range in the Coast Ranges from Del Norte County to Mendocino County, usually below 4000 feet.
Historical references place the Northern red-legged frog in the Inglenook Fen – Tenmile Dune Nature Preserve and they are likely to occur in the project area. Survey for rana aurora aurorai prior to project initiation will occur by trained park staff. In the event Northern red-legged frogs are detected within the project area mitigation will be implemented. The MacKerricher Dune Rehabilitation Project would have a less than significant impact on Northern red-legged frog populations following mitigation measures.
Western (Pacific, Coastal) tailed frog (Ascaphus truei) – The Western tailed frog is considered a California Species of Special Concern by the California Department of Fish and Game due to threats from timber harvest and poor water quality during vulnerable life stages. The western tailed frog aquatic larvae require 2 to 3 years to transform in permanent streams of low temperatures occurring in conifer-dominated habitats including redwood, Douglas fir, mixed-conifer and ponderosa pine. Presently populations are known only from Del Norte, Siskiyou, Humboldt, Trinity, Shasta, Tehama, and Mendocino counties.
Removal of the haul road and culverts will temporarily alter Fen Creek and Inglenook Creek at the mouth of both drainages. Habitats about the project area at the creeks include riparian consisting of Wax Myrtle and willow shrub and coastal dune; but do not include any conifer dominated habitats. Due to the habitat requirements of the tailed frog it is unlikely to be present in the project area. Therefore, the project will have no negative impact on Western tailed frog populations.