2009 Noxious Weed Survey
Middle Rosewood Creek Implementation Area A
Incline Village, Nevada
A noxious weed survey was conducted June 23, 2009 by a Wood Rodgers botanist for Middle Rosewood Creek Area “A” SEZ Restoration Project in Incline Village, Nevada.
This area was resurveyed subsequent to a preliminary noxious weed survey conducted in December 2008 to ensure an adequate level of survey as the December 2008 survey may have missed some weedy species due to winter dormancy. The project area was traversed in a series of meandering, pedestrian transects on each side of the creek, with particular attention paid to areas with fill, and disturbed areas exhibiting bare soil, including road shoulders, creek banks, and trail crossings. Conditions during the survey consisted of clear, sunny weather, with plant species identifiable to the species level.
The project area is characterized by a riparian corridor adjacent to Rosewood Creek within a Sierra mixed conifer forest dominated by Jeffrey pine (Pinus jeffreyi) and white
fir (Abies concolor). Dominant overstory riparian vegetation is provided by mountain alder (Alnus incana ssp. tenuifolia), Scouler’s willow (Salix scouleriana) and Pacific
willow (S. lucida ssp. lasiandra). A shrub layer is typically noncontiguous along the
stream bank, except for discrete occurrences of red osier dogwood (Cornus sericea),
Wood’s rose (Rosa woodsii) and Lemmon’s willow (S. lemonnii). The herbaceous
understory varies from dense cover of mesic gramionoids like small-fruit bulrush (Scirpus microcarpus) and sedges (Carex spp.), and dry graminoids like blue wildrye
(Elymus glaucus) to that composed of forbs including western brackenfern (Pteridium
aquilinum), stinging nettle (Urtica dioica), and Anderson’s thistle (Cirsium andersonii).
Most of the survey area exhibited a thick litter layer composed of pine needle duff/bracken fern in the uplands and decomposing, deciduous herbaceous material at the ordinary high water mark, precluding the establishment of weedy species. Additionally, considerable clearing of dead and dying woody material and undergrowth has been accomplished over the last year between the established homes/condominiums and the creek, with some pathways more well-defined and wood chips put down as cover. Some willows appeared to be regenerating from the cut stumps. Erosion control species have been seeded adjacent to SR28 and include the grasses bottlebrush squirreltail (Elymus
elymoides), California brome (Bromus carinatus) bluegrass species (Poa secunda,
P.ampla), and wheatgrasses (Agropyron cristatum, Elytrigia intermedia). Additionally,
mountain big sagebrush (Artemisia tridentata ssp. vaseyana), blue flax (Linum lewisii)
and beardtongue (Penstemon sp.) were evident.
Disturbed habitat that might support weedy species was observed adjacent to SR28 and Northwood Boulevard, and the real estate office parking lot/boat storage near the northwest start of the project area. In a few places creek banks, and trails crossing the creek also exhibited bare ground, but did not support any herbaceous vegetation in those cases. Common weedy species observed included yard knotweed (Polygonum avicualre),
curlycup gumweed (Grindelia squarrosa), prickly lettuce (Lactuca serriola), tumble
mustard (Sisymbrium altissimum), bulbous bluegrass (Poa bulbosa) and filaree (Erodium
The Nevada Department of Agriculture Noxious Weed List (2005) and the Priority Invasive Weeds of the Tahoe Basin list (LTBWCG 2007) were reviewed to ascertain the status of potentially weedy species found within the project area. No Nevada noxious weeds were identified as occurring within the project area. Two Priority Invasive Weed species of the Tahoe Basin were identified as occurring within the survey area, teasel (Dipsacus fullonum -Group 1: Watch for, Report, Eradicate Immediately, present as only small, eradicable populations) and bull thistle (Cirsium vulgare - Group 2: Manage
Infestations with a Goal of Eradication, isolated populations will be targeted for eradication). Teasel clumps identified in December 2008 on the west side of the creek and north of SR28 are still present: two clumps are present adjacent to the parking area for the real estate office, and one clump just below this on the west bank of Rosewood Creek. Last year’s flowering stalks were present and 10+ basal rosettes evident. Near the teasel clumps located by the parking area, one bull thistle plant was also found. Additionally, two other locations of bull thistle plants were located between this parking lot, west and south of the creek and north of SR28, for a total of seven additional bull thistle plants in both the flowering stalk and basal rosette stages.
It is recommended that prior to any construction or other ground disturbance associated with any riparian enhancement/restoration project, that the teasel and bull thistle are removed. Additionally, the entire project area should be monitored for these and other noxious and priority weed species post-project implementation.
Lake Tahoe Basin Weeds Coordinating Group (LTWCG). 2007. Priority Invasive weeds of the Lake Tahoe Basin, revised December 2007. Accessed June 25, 2009 @ http://tahoeinvasiveweeds.org/weeds/pdf/PriorityWeedList_12_2007.pdf
Nevada Department of Agriculture. 2005. Noxious Weed List updated 11/06/08. Accessed June 25, 2009 @ http://agri.nv.gov/nwac/PLANT_NoxWeedList.htm