Oakmead Herbarium: Arrivals, Weeds
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How should we guide management . . . My philosophy has four components
- The first is to manage with the lightest touch possible, respecting the path that nature determines.
- Second, we have the opportunity and the responsibility to learn by doing. In our everyday management decisions, we continuously face the question of whether to remove an invasive species, exclude an animal, or mow here rather than there. Docents and staff have managed to keep up with removal of certain invasive plants (e.g., stinkwort, pampas grass, tree-of-heaven), and are making inroads against others (e.g., French broom, yellow star-thistle). We continue to debate an experimental return to cattle grazing as a management tool.
- Third, we can learn from others, building on the rich diversity of approaches and outcomes that we see in nearby preserves and parks. our mission is unique, but wisdom depends on openness to shared knowledge.
- Fourth, much of the management of Jasper ridge is grounded in expert judgment. in some ways, our philosophy may be a bit eclectic, based more on a sense of what is possible than on systematic pursuit of defined goals, but it is based on many decades of collective experience by leading ecologists. The criteria and objectives may not always have the sharpest focus, but they always have a rich “feel” for the system.
—Chris Field, Preserve What? JRBP Annual Report 2013-14, JRBP Faculty Director
One of those questions, and a current focus of research of the preserve, is how to best go about successfully preserving nature, or what is known as intervention ecology. "When Jasper Ridge was formally designated as a preserve, there was good reason to believe that it was a self-sustaining environment, that natural processes would sustain the natural biodiversity, for example," said Chiariello. "That worked for a while, but it's now clear that with invasive species and other pressures that won't be a sustainable practice for the future."
In 2004, a new strategic plan for Jasper Ridge revised the founding "do-not-interfere" policy and opened a case-by-case discussion on how to strategically tweak an existing ecosystem – either at the preserve or elsewhere – to put it back on a natural path. "We're really interested in restoration now, but to do this effectively we need to first know, for instance, how important it is that you seed an ecosystem with a critical species first so that it can take off on its own," Chiariello said. "We can begin to understand that with the Mimulus system." (http://news.stanford.edu/news/2013/may/jasper-ridge-anniversary-051013.html)
—Nona Chiariello, JRBP staff scientist
Like it or not, all our concepts for evaluating ecological change are based on cultural (and therefore changeable) values. Stephen Jay Gould once wrote that the one and only biological defense he could concoct for native species was the protection they “afforded against our overweening arrogance.” We can know how native flora behaves in its existing habitat, but we can never know the long-term consequences of introductions into new habitat. Only a small percentage of novel species will become nuisances, but we are bad at predicting which ones. Although Gould considered the biological argument to be “no mean thing,” he added an ethical defense: by privileging natives, we discourage “the botanical equivalent of McDonalds’ uniform architecture and cuisine” and promote a “maximal amount of local variety.” . . . No one likes the sound of the Homogocene, the neologism for the current era of human-facilitated species shifting. To flatten the world with sameness seems unethical. It goes against the current of evolution.
—Jared Farmer, Trees in Paradise, p. 213
While the rate of naturalization by exotics at Jasper Ridge may have leveled in recent years, new species capable of moderate to severe impacts continue to arrive. These include over the past three decades Brachypodium distachyon, Brachypodium sylvaticum, Briza maxima, Dittrichia graveolens (Aster Family), and Ehrharta erecta. Lolium multiflorum, long present on the Preserve and recorded in each flora beginning with Springer (1935) invaded the serpentine prairie during the 1960s becoming a dominant plant of that habitat. > = post; < = prior to; CCH = Cosortium of California Herbaria
Documented waifs, agricultural weeds, garden escapes, and eradicated exotics
N = not treated in The Jepson eFlora; SPEC—Specimen, at the Jasper Ridge herbarium (JROH); DOC—Documented, plant observed and/or photographed by herbarium team but not vouchered
Abutilon theophrasti (VELVET-LEAF) — SPEC | eFlora — Collected 2006 from resident ranger's yard
N Acer palmatum (JAPANESE MAPLE) — SPEC — Young plant collected in 2002; not seen since
N Agapanthus (LILY-OF-THE-NILE) — DOC — Red-Hot Poker Meadow. Persistent
Amaranthus retroflexus REDROOT PIGWEED — SPEC | eFlora — Ag weed reported in 1974 and 1975
Avena sativa — SPEC | eFlora — One plant found in dry bed of Searsville Reservoir; 2022
Borago officinalis (BORAGE) — DOC | eFlora — One plant found in the Corte Madera Cr flood plain in 2003; not seen since
N Cannabis sativa (HERB) — SPEC — Extirpated
N Cedrus deodara — SPEC | eFlora — Single small tree near Mapache fenceline. Persistent?
Coreopsis tinctoria (CALLIOPSIS) — SPEC | eFlora— Collected in 1997 at Low Flow Crossing; not reported since
N Crataegus laevigata (SMOOTH HAWTHORN) — SPEC — Single plant removed
Cyperis difformis — spec | eFlora— Collected in 1980; not reported since
Dichondra sp. — DOC — Herbarium 7/27/2005 Bear Cr. crossing; not seen since
Geranium core-core (ALDERNEY CRANE'S-BILL) — SPEC | eFlora
N Hyacinthoides hispanica (SPANISH BLUEBELL) — SPEC— Near Douglas Iris site. Persistent
Iberis umbellata (CANDYTUFF) — SPEC | eFlora — Persistent
Impatiens balfourii (POOR MAN'S ORCHID) — SPEC | eFlora— SF Creek bed; collected once and not seen since
Ipomoea purpurea (COMMON MORNING-GLORY) — DOC | eFlora
Lepidium campestre ( FIELD PEPPERWORT) — SPEC | eFlora — Collected in 1976 in the Searsville Lake–Corte Madera Cr delta; not seen since
Leucanthemum vulgare — SPEC | eFlora
Leucojum aestivum (SNOWFLAKE) — DOC | eFlora, Flickr, Calflora
Ligustrum vulgare (COMMON PRIVET) — SPEC — Persistent
Linaria bipartita — SPEC | eFlora — Two plants in May, 1982 along Sand Hill Road
Lobelia erinus (GARDEN LOBELIA) — SPEC | eFlora
Lycopersicon esculentum (TOMATO)— SPEC | eFlora
Medicago sativa (ALFALFA) — DOC — Springer 1935 “infrequent”; Herbarium report 2000, Rd C bridge
Myrtus communis (COMMON MYRTLE) — SPEC | eFlora— Hermit'a Cabin Site. Persistent, spreading by rhizomes
Panicum miliaceum ssp. miliaceum (BROOMCORN MILLET) — SPEC | eFlora — Collected once 9/2002 in dry bed of Corte Madera Cr; not reported since
N Parthenocissus quinquefolia (VIRGINIA CREEPER) — SPEC | Calflora — Scattered plants in Bear and SF creeks; persisting at least from 2011
Pelargonium grossularioides — DOC | eFlora — 2020
Phleum pratense (TIMOTHY) — SPEC | eFlora — Collected 7/1/2009 in Bear Creek; not reported since
Pisum sativum (COMMON PEA) — SPEC | eFlora — Collected in 1967 along Rd D; not reported since
N Pinus sylvestris (SCOTCH PINE) — SPEC — Persistent; a few survivors of Xmas tree farm
Rhamnus alaternus (ITALIAN BUCKTHORN)— SPEC — One plant persistent since 2016
N Rosa banksiae (LADY BANK'S ROSE) — DOC — Single plant at Hermit Cabin site. Persistent?
N Rosa laevigata (CHEROKEE CLIMBING ROSE) — SPEC — Planted along the Sand Hill Rd. fence between 1975-1980; persistent. Prickles like R. californica
N Rosmarinus officinalis (ROSEMARY) — SPEC — Occasional plant found and removed. Persistent?
Sisymbrium officinale (HEDGE MUSTARD) — SPEC (1935) | eFlora; Dengler 1975; not reported since
Vicia disperma (EUROPEAN VETCH) — SPEC | eFlora — Persistent?
Arrival dates of some naturalized grasses
- Avena spp. (WILD OAT) — <1920 (Cooper, 1922)
- Brachypodium distachyon (PURPLE FALSE-BROME) — 1977 (Dengler, 1984) 1, 6
- Brachypodium sylvaticum (SLENDER FALSE-BROME) — 2007 (CCH) 2
- Briza maxima (BIG RATTLESNAKE GRASS) — 1976 (Dengler, 1984) 3
- Briza minor (SMALL QUAKING GRASS) — <1935 (Springer, 1935)
- Bromus diandrus (RIPGUT) — <1935 (Springer, 1935) “abundant”
- Bromus hordeaceus (SOFT CHESS) — <1935 (Springer, 1935) “abundant”
- Bromus hordeaceus in serpentine (SOFT CHESS) — <1962 (Dengler, 1962-63) 4, 6
- Bromus madritensis rubens (RED BROME) — <1935 (Springer, 1935) “frequent”
- Bromus madritensis madritensis (SPANISH BROME) — <1971 (JH Thomas Suppl. to Porter, 1962)
- Bromus sterilis (POVERTY BROME) — <1990 (CCH)
- Cortaderia selloana (PAMPAS GRASS) — <1969 (MacDonald, 1988). Dengler, 1975: "destroyed Oct. 26, 1969"
- Cynosurus echinatus (BRISTLY DOGTAIL GRASS) — >1962 & <1973 (Grundmann, 1983)
- Dactylis glomerata (ORCHARD GRASS) — <1973 (Grundmann, 1983)
- Ehrharta erecta (VELDT GRASS) — 2003 (CCH) 5
- Festuca myuros (RATTAIL FESCUE) — <1935 (Springer, 1935)
- Gastridium phleoides (NIT GRASS) — <1935 (Springer, 1935)
- Holcus lanatus (VELVET GRASS) — <1900 (CCH)
- Hordeum murinum (FARMER'S FOXTAIL) — <1935 (Springer, 1935)
- Lolium multiflorum (ITALIAN WILD RYE) — <1935 (Springer, 1935) “frequent”
- Lolium multiflorum in serpentine (ITALIAN WILD RYE) — 1962 (Dengler. 1962-63) 6
- Phalaris aquatica (HARDING GRASS) — <1962 (CCH) — earliest report JH Thomas 1962.
- Phalaris paradoxa (HOOD CABARYGRASS) — ~1980 (Dengler, 1984)
- Phleum pratense (TIMOTHY) — Collected 7/1/2009 in Bear Creek; not reported since
- Poa bulbosa (BULBOUS BLUEGRASS) — 2014 (CCH) plants removed
- Polypogon viridis (WATER BEARD GRASS) — <1945 (Moeur)
Some non-graminoid arrivals
- Acacia dealbata (Silver wattle) — earliest report JH Thomas 1971 "Adventive"; aggressively speading in Bear and San Francisquito creeks including serpentinite zones by 2000.
- Ailanthus altissima (Tree of heaven) — <1973 Dengler.
- Carduus pycnocephalus (Italian thistle) — <1973 Dengler.
- Centaurea calcitrapa (Purple star-thistle) — earliest report Springer 1935 “rare”; widespread by 2000.
- Centaurea melitensis (Tocalote) — earliest report Springer 1935 “very abundant.”
- Centaurea solstitialis (Yellow star-thistle) — earliest report Springer 1935 “Rare, one plant found along road in August”; abundant in non-serpentine grassland by the 1970s.
- Cirsium vulgare (Bull thistle) — earliest report Springer 1935 “infrequent.”
- Delairea odorata (Cape ivy) — earliest report 1902 Abrams "Searsville."
- Dipsacus sativus (Fuller’s teasel) — <1945 Moeur.
- Dittrichia graveolens (Stinkwort) — ongoing weeding. First appeared in 2005 in an area that was mowed to create a fire break and in a fire-staging area near the boundary of Portola Valley's Westridge neighborhood
- Genista monspessulana (French broom) — earliest report JH Thomas 1960; spreading in creeks and mesic oak woodland.
- Medicago polymorpha (Burclover) — earliest report Springer 1935“abundant.”
- Parthenocissus quinquefolia — earliest report 9/12/2017 in Bear Creek, by Herbarium Group
- Oxalis pes-caprae (Bermuda buttercup) — earliest reports in 1970s.
- Phallaris aquatica (Harding grass) — earliest report JH Thomas 1962.
- Sonchus asper (Prickly sow-thistle) — earliest report Springer 1935 “frequent.”
- Sonchus oleraceus (Common sow-thistle) — earliest report Springer 1935 “frequent.”
- Silybum marianum (Milk thistle) — earliest report Springer 1935 “frequent.”
- Torilis arvensis (Hedge parsley) — earliest report <1973 Dengler.
- Vinca major (Periwinckle) — earliest report <1945 Moeur “rare.”
Vegetation Cover Estimate Diagrams
French broom removal in oak-California fescue woodland between trails 4 and 5
Broom control requires continuous removal until the seed bank is depleted. Caifornia fescue thrives in open oak (blue, black, coast live) woodland on a section of the north-facing slope from the ridgeline downhill to the broadleaf evergreen forest below. Soil appears to be derived from Franciscan rock-types. There are two French broom infestation in this habitat. The upper infestation is about 50 yards long and 5 yards wide and is on the edge of a small drainage. It begins 100 yards or so downhill from trail 4 at 0568073, 4140254. California fescue is growing among the broom. The lower infestation is of similar extent.
This site has excellent floristic value providing habitat for a number of native forbs and grasses, and its understory is dominated by California fescue, which can form a high percentage of cover. This is one of the few terrestrial habitats on the Preserve were the herbaceous phytomass is largely native. A student project used this site in 2008 (Tom, M. 2008. Ecological impacts of French broom invasion management. Senior honors thesis. Department of Biology, Stanford University).
Extensive California fescue woodland is also found on north-facing serpentine slopes on Mount Tamalpais, where it grows in association with oaks, douglas fir, and serpentine chaparral. The Tamalpais habitats can be extensive. As at Jasper Ridge, the California fescue can locally form a dense cover. On Tamalpais as the slope aspect changes from northeast to northwest, widely spaced serpentine reedgrass replaces California fescue as the dominant graminoid. On Jasper Ridge as one follows trail 4 south, the fescue is replaced by annual grasses and a suite of natives characteristic of drier habitats (Nassella lepida, Nasella pulchra, Koeleria macrantha, Elymus glaucus, Poa secunda secunda).
Dec 28, 2006 was the first broom pull. Removed 2,500 plants from the upper infestation, including most of the seed-producing plants. There is a good deal of clean-up required of small plants; most of this work could be done by hand-pulling. We plan to return over the next several weeks or months to complete work on the upper infestation.
- February 7, 2007. Removed 500+ plants from upper broom population.
- February 21, 2007. All seed-bearing plants removed from upper population, about 1000 plants. Started removal of lower population. 4 hours. Hartweg's tauschia leafing out in the area.
- February 23, 2007. Lower population, 1,000+ plants removed, mostly woody. 4 hours.
- March 4, 2007. 1,500 plants removed lower population. 4.5 hours.
- March 8, 2007. 1,500 plants removed lower population. All flowering plants removed from both populations. Also 1 cotoneaster and olive removed from upper, and 1 cotoneaster from lower.
- March 23, 2007. Removed a few hundred seedlings and larger plants previously overlooked, downslope toward small drainage, some in bloom, hand pulling and weed wrench. California King snake in grass.
- Nov, 2008.
- Nov 2, 2008. Removed a few hundred seedlings, hand pulling
- Nov 5, 2008. Removed a few hundred seedlings, hand pulling
- Jan 21, 2008. Removed a few hundred seedlings and some older plants in zone downslope nearest Trail 5, hand pulling
- 2009-2016. Site clean-up of seedlings, hand pulling
Other French broom removal and clean-up
- Douglas iris site at confluence of Bear/SF creeks, 2005 to present; (many mature plants and seedlings). This small area is one of the finest native plant habitats on the Preserve. Douglas iris site vicinity: 100 mature and seedling plants removed in November 2010 and 1/21/2011 on slope leading down to Bear Creek on the uphill side of road-end where the Plectritis spp. and Collinsia heterophylla populations were threatened.
- Trail b near Rd F (50 young plants removed by hand-pulling in 2005, new invasion). Occasional cleanup including 5 small plants 4/4/2013.
- Semaphore grass vernal pond, many mature plants removed (originally a ranger project). More recently broom removed in general area (Trail 18) by work crews.
- Trail 7 just south of Hillside Lab 100 plants in 2011-2016 near Festua elmeri site.
- Bear and SF creeks: Acacia dealbata mapping (partial), 2021
- French broom stand north bank of SF Creek
Chia site Trail b
Ongoing weeding of tocalote, Italian thistle, and scarlet pimpernel in loose scree resulting in a vigorous recovery of native species: Salvia columbariae, Phacelia rattanii, Cryptantha microstachys, Rafinesquia californica, and Pellaea mucronata.
Field Station area
The herbarium group sponsored weeding sessions Sunday 9/21/2014 and Monday 9/22: 9:00-11:00 AM each day. The site is down slope from the field station toward the lake where grows the Preserve's only population of Goldenaster. The rare wooly-headed Lessingia was also blooming nearby as well as hayfield tarweed, hairy birdbeak, and naked buckwheat.
Bear Creek (Parthenocissus)
9/20/2017 "We walked Bear Cr from Sand Hill to the confluence with Corte Madera and removed Parthenocissus from 6 locations, including two on the South side of the creek (one was climbing in a willow). We got all the roots we could from all patches." -- Nona Chiariello
Sources: references relevant to the floristics of Jasper Ridge Biological Preserve.
1 Brachypodium distachyon was first noted on the Preserve June 4, 1977 by Herb Dengler “west of the lake above the beach (second year of drought).” (Specimen: Dengler s.n. ) This grass was not recorded in John Thomas (1961) Flora of the Santa Cruz Mountains of California.
2 A single plant was found in 2007 inside the Preserve’s Sandhill Rd fence south of the main gate; the plant was removed. A single plant was discovered along Rd G in 2014 and removed. In Fall 2015 1,000s plants were found south of Middle lake in a discontinuous band under willow canopy and replacing native understory of Scirpus microcarpus, Cyperus eragrostis, and Persicaria punctata. False brome may eventually spread along San Francisquito Creek where it will join veldt grass (Ehrharta erecta), native to South Africa, in the forest understory of the Preserve’s broadleaf evergreen forest and redwood groves. MROSD. 2016. Ten-year Status Report and Recommended Continuation of a Slender False Brome [Brachypodium sylvaticum] Integrated Pest Management.
3 Briza maxima was first reported June, 1976 by Herb Dengler from the vicinity of Bear Creek.
4 Bromus hordeaceus in serpentine: Bromus hordeaceus was present in serpentine earlier than Spring 1962 [see Lolium note below] but evidently uncommon. Dengler writes in his fieldnotes of 21 May 1974, that soft chess “. . . seems taller than I recall it ever before, reaching better than 2ft on occasion. During grazing days [prior to April, 1960] B.m. [Bromus mollis] was rare on serpentine. Now it is abundant. Consequently wild flowers are fewer and sometimes stems necessarily longer.” In 1966 MacNaughton (1968) measured species rank by above-ground biomass in four serpentine plots on different slopes and aspects. Cumulative totals for two most abundant plants were Stipa pulchra 30% and Bromus hordeaceus 24.4%.
5 The Herbarium team removed a single plant from the Low Flow Crossing area of San Francisquito Creek in 2003. In 2005 ten or so Ehrharta erecta plants were observed fruiting in early December along Bear Creek and Sand Hill Rd at the Preserve boundary fence. Ehrharta can now be found downstream in and along Bear Creek and San Francisquito Creek and is also well-established away from the San Francisquito Creek around the Indian grinding rock near the beginning of Trail a and The Cave Trail.
6 Lolium multiflorum appears in all JRBP floras. With the transcription of the 1962/63 volume of Herb Dengler's field notes the earliest record to date has come to light. On May 19, 1962 Dengler wrote, evidently with reference to both Bromus hordeaceus and Loliu, "Mediterranian grass has successfully invaded the serp this year." (Brachypodium distachyon probably invaded serpentine post-1977.) Prior to the Dengler record we knew that Springer (1935) found Italian rye grass to be "frequent along roadsides and in open fields and on openly wooded slopes near roads." Thomas (1961) did not report Italian rye grass growing on serpentine in the Santa Cruz Mountains. McNaughton (1968), whose sampling was done in 1966, did not find Italian rye grass in his serpentine plots. In 1990 the third revised edition of the Jasper Ridge Docent Handbook still identified only soft chess from among the Preserve's naturalized grasses growing on serpentine. Armstrong and Huenneke (1993) documented Lolium to be common in serpentine in 1985-86 -- and that it was negatively effected by drought. In 2001 and 2002 Lolium accounted for 32% and 20%, respectively, cover of Stuart Weiss' JRBP serpentine transects (Weiss, 2002). In Spring 2006 the herbarium crew assisted in a repeat of the Armstrong and Huenneke transect and the vegetation component of a small mammal inventory. It is our impression that Lolium was dominant in many of the serpentine quadrats. Hobbs et al. (2007, p.554-45) data shows lower coverage and frequency of Lolium for 1983-2003 in his quadrats. The herbarium crew has not examined Hobbs' 50 x 50 m quadrats. Also see CNPS Vegetation Rapid Assessment Field Form JASP0001 3/25/2008.
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