the ardeid newsletter, 2005 ~ audubon canyon ranch

8/9/2019 The Ardeid Newsletter, 2005 ~ Audubon Canyon Ranch

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sharing the landscape

with herons and egrets

Common Water

expanding Olema

Marsh restoration

Habitat Connectivity

protecting rare and

uncommon plants

Stewardship Ethic

research & resource

management plan

Beyond Gardening

2 0 0 5

the

Ardeid

Research and

Resource M anagement

at Audubon Canyon Ranch


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3/16

2005 the ARDEID page 1

If you watch herons and egrets care-fully, for a long time, over a wide area,it becomes obvious that their lives are

closely linked to ours. This is not surpris-ing, because the lives of herons and egretsare sensitive to the health of our bays,marshes, beaches, and creeks, and there-fore, how we manage water. Herons andegrets feed in ranch ponds, levee

marshes, flood control channels, seasonalfarmland, recreational parks, city creeks,

water treatment ponds, and wetlandrestoration sites. In addition to buildingnests in tule marshes, on isolated islands,and in forested coastal canyons, theyestablish colonies in suburban neighbor-hoods, in rural patches of introducedeucalyptus, and on dredge-spoil islands.They can be seen almost anywhere.Nonetheless, the delight one experiencesupon noticing the enchanting profile ofan egret, whether along a secluded shore-line or in a roadside ditch, is at leastpartly inspired by the sudden sense ofshared space. This recognition is at theheart of ACRs Heron and Egret Project,

which seeks to understand not only thelives of these beautiful birds but also ourrelationship to the wetland systems theyseem to symbolize.

The popular use of herons and egretsin the iconography of wetland conserva-tion is well substantiated by the ecologi-cally important roles they play. Theirimportance as powerful wetland preda-tors is matched by their sensitivity to sub-tle changes in ecosystem productivity,hydrology, vegetation, and human activ-ity. Ecologists recognize such relation-ships and consider the lives of herons andegrets to be valuable indicators ofprocesses that sustain or threaten healthy

wetlands. Because these birds range overlarge areas, their responses to environ-mental changes may be useful in under-standing processes that affect whole land-scapes, including the effects of wetlandrestoration projects on surrounding areas.This exciting prospect, however, is still a

work in progress (see sidebar on page 3).

An atlas of heronries

Audubon Canyon Ranch is completingan annotated atlas that illustrates anddescribes the distribution, status, andtrends of herons and egrets in the San

Francisco Bay area. The work is based on14 years of observations at more than 100heronries known to exist in the region(Figure 1). Longer periods of monitoringare reported from selected sites such asMallard Slough in the South Bay (19

years), Marin Islands near San Rafael (25years), and ACRs Picher Canyon heronrynear Bolinas Lagoon (37 years). The atlasincludes important contributions by theSan Francisco Bay Bird Observatory,based on long-term monitoring in SouthSan Francisco Bay. The completed reportprovides a regional assessment, detailed

colony-site accounts, asearchable database, andmaps of heron and egretnesting populations. Theresults are presented in for-mats that can be importedby county planners intogeographic informationsystems (GIS), referenced

by policy makers and con-servation groups, and dis-tributed widely to otherinterested individuals andorganizations. Soon, it willbe freely available for down-load from the ACR web site(http//www.egret.org).

The initial section of theatlas provides a detailedlook at the status andtrends of regional heronand egret populations.Overall, numbers have

been fairly stable (Figure 2),but they can reveal regionalphenomena that affectpopulations. For example,the 1999 decline in nestingGreat Blue Herons, GreatEgrets, and Snowy Egrets(Figure 2), which was espe-

cially evident in Suisun Marsh and SouthSan Francisco Bay, was apparently associ-ated with reduced recruitment of first-time breeders born two years earlier.Extremely dry conditions during late win-ter and spring of 1997 (Figure 3) may have

severely limited the extent of water avail-able in levee marshes in the South Bayand Suisun Bay, and nest failure rates that

year were unusually high. In addition,those nestlings that survived the 1997breeding season subsequently faced anintense beating by El Nio storms whilelearning how to feed proficiently enoughto survive their first winter. Based on thisinformation, it seems reasonable thatbreeding season droughts followed byheavy winters might predict declines inregional nesting populations. This, in

Sharing the landscape w ith herons and egrets

Common Water

by John P. Kelly

Figure 1. Heron and egret nesting colony sites included in ACRs

annotated atlas of heronries in the San Francisco Bay area (solid

and open circles). Colony sites within 10 km of the historic tidal

marshes (shaded areas) of San Pablo Bay and Suisun Bay (open cir-

cles) were used to analyze landscape use by herons and egrets in

the northern San Francisco Estuary.


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page 2 the ARDEID 2005

turn, might lead to reduced levels of pre-dation in regional wetlands.

Differences in heron and egret activityat subregional or local scales often revealdistributional shifts that can be traced tolocalized disturbances by predators orhumans. For example, a dramatic influxof Snowy Egrets in Napa County wasassociated with a major decline in nestingSnowies at the Marin Islands, near SanRafael, in 1994 and 1995. This decline wasapparently the result of persistent, mis-

chievous disturbance by a single Red-tailed Hawk (seeArdeid, winter 1995). In2000, Great Egrets colonized a new site inDrakes Estero, in the Point Reyes NationalSeashore. This occurred within a week ofthe abandonment of a colony inInverness Park, which was apparentlycaused by intense disturbance and nestpredation by resident Common Ravens.

If monitoring efforts are limited to par-ticular heronries, the movements of birdsamong sites are likely to mask any under-lying regional trends. Because region-

wide monitoring did not occur until the

1990s, we are just now positioned todetect possible long-term responses ofregional heron and egret populations to

wetland protection and restoration.Shared patterns of activity among

heronries within a subregion can be ofparticular interest. We are currently

watching closely to see if recentincreases in the numbers of nestingherons and egrets in the Petaluma andNapa marshes signal benefits related tonearby wetland restoration projects.Evidence of shared benefits generated bygroups of restoration projects could

inspire new approaches in restorationplanning.

Since the mid-19th century, over 95%of the Bay Areas tidal marshes have beendrained or filled for agriculture or devel-opment, converted to salt ponds, oraltered by levee construction (Atwater etal. 1979, in Conomos, San Francisco Bay:the Urbanized Estuary). Now, afterdecades of Clean Water Act protectionsand restoration of former wetlands,heron and egret numbers seem to be sta-

ble, showing no obvious declines but alsono evidence of continuing recovery inresponse to the mounting numbers of

wetland restoration projects. One possi-ble explanation is that the restoration of

wetland quality comparable to naturalsystems may be largely unrealized. Forherons and egrets, this means that eachrestored marsh must produce more preyor provide better foraging conditions forcatching thema simple but very chal-lenging goal!

Measuring success

Finding enough food is only one of

several requirements for successful nest-ing. Reproductive performance mayinvolve multiple ecological processes,each influencing a different componentof nesting success. For example, the likeli-hood that a heron or egret nest will fledgeat least one young depends primarily onthe combined risks of predation andsevere weathereither of these candestroy an entire clutch or brood. Astrong wind can blow nests, eggs, and

young right out of a tree.In contrast, the number of young pro-

duced by successful nests depends pri-

Figure 2. Annual sum of the peak number of

active heron and egret nests observed at

heronries in the San Francisco Bay area,

19912004.

Figure 4. Mean number of young produced in successful Great Egret and Great Blue Heron nests,

by subregion, in the San Francisco Bay area, 19912004.

Figure 3. Cumulative rainfall during the nesting

season, February through June, 19912004,

recorded in San Francisco (California Data

Exchange Center, Department of Water

Resources).

Num

bero

fac

tivenes

tsMeannum

bero

fyoung

insuccessfu

lnes

ts(SE)

Year

Year

Great Egret Great Blue Heron

Seasonra

infa

ll(inc

hes

)


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tend to produce more young in all subre-gions, presumably because most or all ofthe associated wetlands are more produc-tive. In other years, lower productivity pre-vails across the region. These patternsprovide good evidence that heron andegret productivity is sensitive to large-scale processes such as weather patterns.

The effects of subregional differencesin habitat quality on heron and egret


marily on food availability and chick pro-visioning rates and, consequently, on wet-land productivity and foraging condi-tions. When more food is available, par-ents can raise larger broods.

To help distinguish between ecologi-cal processes that affect reproduction, wetrack nest survivorship (the proportion ofnests that fledge at least one young) andprefledging brood size (the number of

young produced in successful nests) sep-

arately. Multiplying these two measurestogether gives the number of young likelyto be produced from any nest attemptagood measure of overall reproductiveperformance. We can use this informa-tion, based on subsets of monitorednests, to estimate the productivity ofentire nesting colonies.

Regional trends in the productivity ofsuccessful nests show that subregions vary

together (Figure 4). In some years, nests

How do herons andegrets influence andrespond to ecologicalchanges in the wetlandlandscape? Recently, weidentified potentiallyimportant associationsbetween heronries andthe regional landscape.

As contributors to theIntegrated Regional

Wetland MonitoringProgram for the SanFrancisco Estuary(California Bay-Delta

Authority,http://www.irwm.org),

we worked with land-

scape ecologist DianaStralberg (PRBOConservation Science)to generate informationabout the wetlands sur-rounding each heronrynear the Petaluma,Napa, and Suisunmarshes.

We analyzed land-scape associationsbased on the arealextents of land covertypes (from Landsat

images, 20002002) andon several metricsrelated to wetland patchshape, size, and configu-ration, within 1, 3, 5, 7,and 10 km of eachheronry. Comparisons with randomlyselected, unoccupied sites indicatedthat herons and egrets actively selectnesting areas with more estuarine emer-gent wetland and open water nearbythan normally available in the wetlandlandscape (Figure 5). In contrast, long-term patterns of productivity among

successful nests were significantlyrelated to wetland landscape conditions

at relatively large spatial scales of 510km from heronries (Figure 6).

We also used aircraft to track the for-aging flights of Great Egrets departingfrom heronries. With these data, wemodeled foraging dispersion accordingto (1) the distance from heronries and(2) the extent of available tidal/non-

tidal wetland habitat. Preliminaryresults indicated that most Great Egrets

foraged within a few km ofheronries or within dis-tances that encompassedless than 15 km2 of emer-gent wetland habitat.Further analysis of thisinformation revealed spatialdifferences in potential pre-dation by Great Egrets forag-ing at particular sites in the

wetland landscape.We are excited about this

direction of investigationand hope to find new waysto use information onherons and egrets toimprove the management

and restoration of wetlands. Futureinvestigation will focus on incorporat-ing measurements of foraging habitatquality and validating models of forag-ing dispersion with surveys of particular

wetland sites. Insights into landscapevalues important to herons and egretscould help ensure that these beautiful

birds continue to occupy our marshes.

Herons and egrets as a landscape process

Figure 5. Local influences: herons and egrets establish colonies at sites with

significantly more estuarine-emergent and open-water habitat within 1 km (solid

lines) than available by chance (dashed lines) in the wetland landscape.

Figure 6. Large-scale influences: mean brood sizes over 14 years indicate that Great Egrets produce more young if

heronries are surrounded by more estuarine emergent wetland within 10 km and more wetland edge (relative to

patch area) within 5 km. Great Blue Herons produce more young at heronries with more open water habitat within

10 km. Local habitat conditions have no additional influence on brood size.

continued on page 11

Mean

broo

ds

ize

Proport

ion

ofarea

S

E

Radius of area surrounding the site (km)

Great Egret Great Egret Great Blue Heron

Estuarine emergent wetlandwithin 10 km (km2)

Mean shape indexwithin 5 km

Open waterEstuarineemergent

wetland

Open waterwithin 10 km (km2)


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The dramatic beauty of coastalMarin provides an inspiringpanorama for illustrating some

concepts in conservation biology perti-nent to the future of ACRs Olema Marsh.

When considering management optionsfor Olema Marsh, it is important not tolimit our perspective to the quality oflocal habitats, because populations oforganisms are rarely restricted to a physi-

cally circumscribed place or time andusually need to disperse or migrate inresponse to changing environmental con-ditions. In addition to sea level rise,regional, landscape and local habitatprocesses influence Olema Marsh, whichin turn, affects its contribution to othercoastal systems.

Defining an appropriate region forOlema Marsh and the Tomales Bay water-shed depends upon the species of inter-est. The North American Pacific Flyway isof critical importance for many species ofmigrating birds, which depend upon

numerous wetlands and coastal embay-ments to rest and feed. Unfortunately, themajority of coastal wetlands have beendestroyed, and distances between suit-able habitats are increasing. Thus,improving the condition of Tomales Baymarshes and their watersheds can pro-vide benefits for species whose range ofdistribution extends far beyond the locallandscape that we cherish.

Evolutionary Significant Units (ESU)for Pacific salmon provide regional classi-fications that are particularly relevant tothe future of Olema Marsh. EvolutionarySignificant Units reflect relationshipsbetween geography and biological func-tions that are important in populationgenetics. ESUs also demonstrate theimportance of habitat quality and con-nectivity that can be used to focusrestoration and conservation efforts at thelandscape level to benefit salmonids andother species (see sidebar on page 5).

The Tomales Bay watershed is an

appropriate boundary to describe the

landscape surrounding Olema Marsh.Landscape-level investigations examineinteractions among habitats, such asnutrient transport, predation pressure,and gene flow, that are critical to the sur-vival of populations. Habitat connectiv-ity is particularly important in aquaticsystems. Plants and animals are influ-enced by the condition of surroundinghabitats even if they never occupy these

areas. The characteristics of specifichabitats that support native plants andanimals should be evaluated carefully

when assessing the impacts of distur-bance or designing habitat restorationprojects for the benefit of communitiesof organisms or species of concern.

Olema Marsh: past, present,future

To understand how Olema Marshinteracts with the larger landscape orregion, it is important to review changesin land-use patterns, management, andrestoration efforts. Two hundred years

Expanding restoration opportunities for Olema Marsh

Habitat Connectivity

by Kat ie Etienne

Tidal and freshwater

influences from

Lagunitas Creek

Sir Francis Drake

Boulevard

Olema Creek

Bear Valley Creek

Blocked culvert on

Bear Valley Road

Blocked culvert on

Levee Road

Pulses of sediment

from roads and

creeks in the Bear

Valley w atershed

enter Olema Marsh

during winter floods.

Figure 1. Olema Marsh has been included in the study area for the Giacomini Wetland Restoration Project in the southern end of Tomales Bay. Leveed roadsand blocked culverts impede freshwater and tidal circulation, which alters vegetation patterns and animal distribution.


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ago, Olema Marsh was part of an exten-sive delta salt marsh extending up Bear

Valley and Olema Valley from the mouthof Lagunitas Creek. In the early 1900s, alevee was constructed across these valleysto create Levee Road (a short section ofSir Francis Drake Boulevard; see map).

Olema Marsh receives water from thesmaller Bear Valley watershed, located

west of the Olema Valley.Before Audubon Canyon Ranch

acquired the property in 1972, the ownersof a duck club regularly burned the marshvegetation to create areas of open waterand improve opportunities for duck hunt-ing. By 1982, cattail and tules coveredmost of the marsh, so Audubon CanyonRanch developed an enhancement planfor Olema Marsh with funds from theCalifornia Coastal Conservancy. The pri-mary objectives were to restore open-

water habitat for birds and improve circu-lation of water in the 40-acre marsh.Circulation channels were constructed,sediment was removed from existingponds, and additional deep-water ponds

were created with steep banks to limitencroachment of vegetation. The ponds

were connected to a main channel toimprove water circulation, and dredgedmaterial was formed into islands.

As predicted, bird and vegetationmonitoring indicated that increased cir-culation and the extent of open water

were beneficial for marsh birds. Analysis

of marsh use by the ten most commonspecies showed upward trends over anine-year period (Evens and Stallcup1985, 1991, 1992, 1993, 1994). Therecruitment of willows along the marginsof the ponds provided additional habitatfor songbirds, including the Salt MarshCommon Yellowthroat, which adapts itsforaging behavior to the seasonaldynamics of wetland habitats (Kelly and

Wood 1996).Although the 1983 marsh enhance-

ment project improved conditions forsome birds, it is clear that habitat values

cannot be sustained without active man-agement. In addition, managementefforts must consider physical processesthat occur at larger scales. For example,sediment from the Bear Valley watershedis deposited in Olema Marsh during win-ters with heavy rainfall and is rapidly col-onized by cattails, bulrushes, and willowsthat impede water circulation. During theEl Nio storms of 19971998, sedimentfrom roads in the Silver Hills residentialarea contributed to the blockage of the

west culvert under Levee Road and aver-age water levels in the marsh increased

approximately two feet. Water circulationdecreased in the riparian portion of themarsh next to Bear Valley Road, creatingnumerous snags, but some healthy aldersand willows survived. Currently, winterrunoff flows across Olema Marsh andenters Lagunitas Creek through the east-

ern culvert under Levee Road. However,additional recruitment of willows alongLevee Road has reduced water velocityand promoted sediment depositionaround both culverts.

In 2003 and 2004, ACR staff met severaltimes with wetland experts and biologistsat the Point Reyes National Seashore toshare information and consider how thealternatives being developed for theGiacomini Wetland Restoration Project(GWRP) might influence Olema Marsh. It

was decided that Olema Marsh should beincluded within the project boundary forthe GWRP, to improve ecological functionat the landscape level. Another reason forincluding Olema Marsh in the GWRP wasthat a large proportion of special-statusspecies relevant to the project occur inOlema Marsh (Avocet Research, 2003)

To evaluate the current condition ofOlema Marsh, ACR Research AssociateRich Stallcup conducted breeding and

winter bird surveys in 2004 and 2005.Gary Fellers conducted a survey of thefederally threatened California red-legged frog(Rana aurora draytonii).Darren Fong, biologist for Golden Gate

National Recreation Area, looked for thefederally endangered tidewater goby(Eucyclogobious newberryi), which hepreviously found in a small creek on theGiacomini Ranch. Lorraine Parsons,Project Manager for the GWRP, conductedthe wetland delineation and will include

results of these and other studies in theEIR/EIS for the Restoration Plan.

The Plan depends primarily on topo-graphic studies by Kamman Hydrology,Inc. The 2004 topographic analysis showsthat Olema Marsh is essentially flat, withmost elevations ranging between six andseven feet well above the mean higher-high tide level (67 ft NGVD29). Thisexplains why there is little, if any, salt-

water intrusion. Therefore, two of the pro-posed alternatives are likely to involvereplacing the east culvert in Levee Road

with a bridge or causeway that wouldimprove physical and biological connec-tions between Olema Marsh and TomalesBay. The undersized culvert under Bear

Valley Road also impedes freshwater flowthrough the marsh and contributes toprolonged flooding upstream from Bear

Valley Road.The big question is whether the

velocity of water from Bear Valley Creekis sufficient to maintain a constructedstream channel through Olema Marsh.Fortunately, the Point Reyes NationalSeashore has received a grant from the

A regional approach to stewardshipis critical for the survival of salmon,

which depend upon the quality andconnectivity of different habitats

throughout their life cycles.Efforts to sustain wild populations

have led to the identification ofEvolutionary Significant Units for man-aging salmonids with similar geneticcharacteristics that evolved in responseto common ecological conditions. TheCentral California Coast EvolutionarySignificant Unit (CCCESU) for cohosalmon (Onchorynchus kisutch)includes coastal tributaries from PuntaGorda, near Cape Mendocino, to theSan Lorenzo River near Santa Cruz. TheCCCESU for steelhead (Onchorynchusmykiss) differs because it includes habi-tat for both anadromous steelhead andresident freshwater rainbow trout thatuse inland tributaries of the RussianRiver, San Francisco Bay, and Monterey

Bay watersheds, as well as coastalstreams.

Despite apparent declines in cohoabundance in the southern portion of

the CCCESU, Lagunitas Creek andsome of its tributaries continue to pro-vide essential spawning and rearinghabitat for both coho and steelhead.The prospects for restoring native fishpopulations in Bear Valley Creek areparticularly promising, because most ofthe watershed is under the protectionof Point Reyes National Seashore and

Audubon Canyon Ranch. Our sharedcommitment to improve hydrologicconnectivity between Bear Valley Creek,Olema Marsh, Lagunitas Creek, andTomales Bay, and the presence of adultsof both species in nearby Lagunitas andOlema Creeks, increase the possibilitythat habitat for native fish populationscan be sustained in the future.

Evolutionary Significant U nits provide models formanagement at a regional scale.

continued on page 12


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Downingia pusilla is a belly plant, aslim centimeter of stem bearing a hope-ful white blossom. This wildfloweroccurs within Sonomas vernal pools, amiraculous California habitat type thatis found only where topography collectsrainwater into small basins and soilcharacteristics prevent drainage. Each

pool is a discrete watershed, fed by rain-water and drained only by evaporation,that supports a beautiful and highlyadapted suite of native plants. In May of1921, when the legendary botanist WillisLinn Jepson collected Downingiapusilla specimens in Sonoma Valley, the

Valley contained hundreds of vernalpools in which the tiny plant couldthrive. Today the valley floor is occupiedby humans and their structures, roadsand vineyards have replaced the tinyflower-filled pools that were once dwarfdowningias home.

Recent botanical surveys atACRs Bouverie Preserve havediscovered a new and unex-pected home for this bittyblossom. While the plant islikely lost from Bouveries ver-nal pools, which are domi-nated by European grasses,Downingia pusilla is abundantin one of Bouveries aban-doned quarries. As with natu-rally occurring vernal pools,the depression left by 19th-century quarrying operations

floods each winter and dries each sum-mer, leaving behind a small mud plainthat is virtually devoid of topsoil,uncolonized by invasive weeds, andrich in short-stature vernal pool plants.Ironically, vernal pool plants find moresuitable habitat conditions in this

human-created refuge than in the adja-cent natural vernal pools.

The absence of these plants fromadjacent vernal pools, their home formillennia, indicates the extent to whichthe system has changed. The naturalpools are currently dominated by inva-sive European grasses and forbs, highlycompetitive plants which easily excludeshort-stature native wildflowers. Theinvasive European plants may also befertilized by the nearby highway; recentstudies have shown that automobilesemit very large quantities of plant avail-

able nitrogen that can alter the com-petitive balance in nutrient-poor sys-tems such as vernal pools. We are cur-rently experimenting with grasslandmanagement to reduce the biomass ofcompetitive European grasses, and wehope to collaborate with scientists andneighboring vernal pool managers toassess the level of highway-generatednitrogen deposition. Results of theseprojects should provide information toplan the restoration of ACRs damagedvernal pools.

The fortunate reappearance of Downingia pusilla


On December 28, 1973, RichardNixon signed the EndangeredSpecies Act, far-reaching legisla-

tion approved by nearly unanimousvotes in the House and Senate, whichmade protection of endangered species amajor priority of government. While thecommitment of resources entailed in theESA was unprecedented, the underlying

philosophy is simply a modern codifica-tion of an essentially spiritual responsi-bility. This philosophy was present in theearliest of human writings, including thedirective in Genesis to tend and keepthe Gardena phrase that combinesHebrew verbs for slavish work and culti-vation and maintaining, cherishing,observing, and protecting. The ethic ofenvironmental stewardship is reflectedin many traditions: it is a human ethic.

The primary mission of AudubonCanyon Ranch is to preserve and protectour lands as sanctuaries for native plants

and animals, and ACR has saved some ofthe most diverse and beautiful parts ofour region. While protecting wild habi-tats from urbanization and humandevelopment is a critical first step, long-term preservation requires much more.Even on protected lands, ecosystems arealtered by changes in grazing and distur-bance regimes and by the rapidly accel-erating biological invasion crisis.

Without active and ongoing manage-ment, many of the species we cherish arelikely to disappear; this fate is particu-larly likely for species that are already

rare. In this article I review ACR rareplant stewardship, assess challenges, anddiscuss the work required to save theserare botanical treasures.

Rarity is actually a rather commoncondition for plants in California. Ofapproximately 7975 plant taxa that occurin the state ( The Calflora Database,Berkeley, CA. http://www.calflora.org), anestimated 2016 (25%) are classified by theCalifornia Native Plant Society as rareand uncommon (CNPS 2005. Inventoryof Rare and Engangered Plants.http://www.cnps.org/inventory); the

Protecting the rare and uncommon plants of ACR lands

Stewardship Ethic

by Daniel Gluesenkamp


9/16

Kelly and Grant Fletcher (1993, Madroo41: 316-327) on the rare Point Reyesbirds-beak(Cordylanthus maritimussubspecies palustris) provided importantinsights into the dis-tribution and popula-tion dynamics of thisthreatened parasiticmarsh wildflower. InSonoma County,

California NativePlant Society volun-teers recently visitedBouverie Preservepopulations ofAmorpha californicavar. napensis andLilium rubescens,completing rare plantsurvey forms forinclusion in the CNPSInventory of Rare andEndangered Plants.These volunteer

number of rare native plants is evengreater than the overwhelming numberof introduced plants (Figure 1). Inventoryof rare plants at ACR depends strongly on

work conducted by ACR biologists andvolunteers, including scientific studies ofrare plants and species lists that integratedecades of botanical observations.Careful review of these lists has led to thediscovery of two rare species:

Downingia pusilla and Stellaria littoralis.These species were not rare when firstdiscovered on ACR lands but are nowconsidered rare by CNPS. To date, wehave identified 15 rare and uncommonplant species known or likely to occur on

ACR lands (Table 1).Once identified, rare plant popula-

tions must be inventoried and regularlymonitored in order to detect threats andensure long-term protection. Volunteershave long played a critical role in theinventory and monitoring of rare plantson ACR lands. Careful research by John


efforts have joined periodic monitoringby ACR biologists.

While ACR volunteers and staff havemade tremendous contributions to pro-tecting ACRs rare plant populations,effective protection of rare plantsrequires a dedicated program that com-

bines passive monitoring and active pro-tection. This realization came partly as aresult of a worrisome discovery made byCNPS Rare Plant Program Director AnnHowald, volunteering her time to visitBouverie Preserves population ofSonoma ceanothus (Ceanothussonomensis). This population was lastinventoried in 1985 by botanists fromthe environmental consulting firmBiosystems, at which time they located19 individuals of this endangered shrub.Twenty years later, Ann Howald, working

with ACR biologist Rebecca Anderson-

Jones, found only a single individualremaining. While we hope to locate moreindividuals, it is clear that the populationhas declined significantly and may be onthe brink of extirpation.

The dramatic and unseen decline ofthe Sonoma ceanothus spurred renewedefforts to monitor ACRs special statusspecies. In the last year, Rebecca

Anderson-Jones has worked with con-sulting biologists to inventory high prior-ity targets, including comprehensive sur-veys of the Bouverie Preserves vernalpools and amphibian surveys through-

out the preserve. This work has providedreasons for hope and causes for concern.For example, vernal pool rare plant sur-veys found an estimated 136,000 individ-uals of the tiny ephemeral flowerDowningia pusilla, but all of these indi-viduals are found in few square meters ofsoil at a single site (see sidebar, page 6).

Figure 1. Total number of plant taxa in,California, number of taxa that

are non-native, and number of taxa that are classified as rare by the

California Native Plant Society. Data are from the Calflora Project

(2005).

Scientific name Common name Rarity Preserve Inventory(CNPS List Status)

Amorpha californica false indigo 1b Bouverie Confirmedvar. napensis

Blennosperma bakeri Sonoma sunshine 1b Bouverie Extirpated

Brodiaea californica Sonoma brodaiea 1b Bouverie Potentialvar. leptandra

Castilleja ambigua Humboldt Bay 1b Tomales Reportedssp. humboltiensis owl's clover

Ceanothus confusus Rincon Ridge 1b Bouverie Reportedceanothus

Ceanothus sonomensis Sonoma ceanothus 1b Bouverie Confirmed

Chorizanthe cuspidata San Francisco 1b Tomales Confirmedvar. villosa spineflower

Cirsium andrewsii Franciscan thistle 1b Tomales Reported

Cordylanthus maritimus Point Reyes 1b Tomales Confirmedssp. palustris bird's-beak

Downingia pusilla dwarf downingia 2 Bouverie Confirmed

Elymus californicus California bottle 4 Bolinas Confirmedbrush grass

Fritillaria liliacea fragrant fritillary 1b Tomales Confirmed

Gilia capitata dune gilia 1b Tomales Confirmedssp. chamissonis

Lilium rubescens Redwood lily 4 Bouverie Confirmed

Stellaria lit toralis shore chickweed 4 Tomales Confirmed

Table 1. Rare and uncommon plants known or likely to occur on Audubon Canyon Ranch lands. The

dearth of information for ACRs flagship preserve, the Bolinas Lagoon Preserve, emphasizes the need

for a system-wide rare species inventory and monitoring effort.

Num

bero

ftaxa

All plants Non-native Rare


10/16


The same surveys also indicated theabsence of the endangeredBlennosperma bakeri, even though thisbeautiful miniature sunflower is presentin identical pools ten meters west ofBouveries fenceline.

I am conducting exploratory surveysand have visited populations of most of

ACRs rare plants to assess threats to theircontinued persistence. Invasive species

are clearly the most significant threat toACRs rare plant populations. This corre-sponds with global patterns, as biodiver-sity loss worldwide is driven first by habi-tat loss and secondly by invasive species(IUCN 2004, IUCN Red List of ThreatenedSpecies. http://www.iucnredlist.org).

While most of our rare plant populationsappear stable, several populations clearlyrequire active restoration to ensure per-sistence. Details of the threats faced bytwo species are presented in the accom-panying text boxes.

As these two examples illustrate, mostof ACRs rare plants are capable of sur-viving in extremely adverse conditionsand can even become very abundantlocally. They are not intrinsically weakspecies that need coddling. Rather, theselineages demonstrate an inspiring will tolive, as demonstrated byDowningia col-onizing an abandoned pit and Chorizantheexpanding into newly reclaimed sand

dunes. Each of these taxa is the productof a singular evolutionary history, eachindividual flower the millionth descen-dant of a unique lineage which devel-oped only once in the history of Earth,and that has been selected to thrive inonly one type of place: Downingia inseasonally flooded vernal pools,Chorizanthe in coastal sand dunes.

When suitable habitat is present thesespecies will thrive, and so the disappear-ance of these taxa from ACR landsreflects not the loss of a poorly adapted

species, but rather the loss of an entirekind of place.

There is inspiration in the ability ofthese lineages to persist in a human-altered landscape, and with each seasonof germination we redouble our efforts tosave the places where these taxa thrive.This ethic of caring for our shared naturallegacy is the passion that founded

Audubon Canyon Ranch, and we remain

committed to sustaining this most nobleof human drives with sound scientificresearch, empowering education, andmindful habitat stewardship.

I recall with painful clarity my first

encounter with Chorizanthe cuspidatavarietyvillosa, the San Francisco spine-flower; a perfectly good shirt was lost toa nap on sand that hid Chorizantheseeds. These spiny seeds are a key ele-ment ofChorizanthes life history, andtheir ability to stick to mobile verte-brates is key to the recovery of ACRspineflower populations.

Chorizanthe cuspidata var. villosa isa sand dune annual, one of a suite ofunusual California plants adapted tothe extreme and dynamic life of livingdunes. Wild coastal dunes are the inter-

face between land and sea, where

oceanic winddrives a con-veyor belt ofscouring sandacross swalesand over dunes.Dunes are sandblasted by year-round winds andmisted withsaline spray, and

when freshwaterrain arrives itrapidly disap-pears throughthe sand. Traits

which conferplant competitive ability in less extreme

conditions are a liability in this extremesystem, and so the dunes provide arefuge for tough, resistant plants suchas Chorizanthe.

Unfortunately, humans have longendeavored to calm the unruly natureof wild dunes. Californias dunes havebeen bound in straightjackets ofEuropean beachgrass (Ammophila are-naria) and South African iceplant(Carpobrotus edulis), species importedfor their ability to spread rapidly andsuppress the active sand that keepsdune systems alive. These introduced

plants have spread widely and now

threaten even the few dune systemsprotected against developers and off-highway vehicles.

Audubon Canyon Ranch protectsseveral acres of coastal sand dunes atToms Point. These dunes support atleast two rare and uncommon planttaxa, San Francisco spineflower(Chorizanthe cuspidata var. villosa) anddune gilia (Gilia capitata ssp. chamisso-nis). Unfortunately, the dunes are domi-nated by European beachgrass, and therare dune plants are essentiallyrestricted to a small section that has not

yet been dominated by the invader. InJune of 2004 I initiated a dune restora-tion project to remove European beach-grass and reclaim the site for the

uncommon dune plants. The strategy isto restore habitat in small segmentsover several years, pacing invasivesremoval such that there is sufficienttime for natives to colonize the freshlyliberated sand.

We are already seeing encouragingresults, and populations ofChorizantheand Gilia have increased dramaticallyafter just a single year. These prelimi-nary results confirm that dune nativescan naturally recolonize restored sites,and we are hopeful that our efforts willsave these fascinating species and the

dynamic system in which they thrive.

Chorizanthe cuspidatavariety villosa:splendor in the sand


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How can Audubon Canyon Ranch

best protect the herons and egretsthat nest at Bolinas LagoonPreserve? The answer to this question isactually rather complicated, involving farmore than owning the site and restrictinghuman visitation. It involves, for example,

the protection of shallow feeding areasand suitable prey species in BolinasLagoon. Other difficult questions of inter-est to ACR include how to protect water-shed processes that sustain our sanctuar-ies, how to distinguish natural fromhuman-caused vegetation change, how tocontrol numerous invasive pests, how to

advance the conservation of shorebirdsthat feed along our shorelines, and evenhow to maintain the periodic flurries ofbutterflies that dance among the wild-flowers at the Bouverie Preserve.

Countless such concerns influence theecological health of ACR sanctuaries andchallenge our approach to stewardship.Such challenges are reflected in a major

revision of ACRs Research and ResourceManagement (RRM) Plan (Table 1).

Although the RRM Plan is filled with pre-scriptions for management, it recognizesthat solutions are often difficult and thatstewardship should be conducted cau-tiously to allow for uncertainties in howthe kaleidoscopic processes of naturerespond and change over time.

Three stewardship themes haveemerged in the RRM Plan. First, thePlan emphasizes the intrinsic naturalvalues of ecosystems over human usevalues, a guiding principle that has

characterized ACR since it began over40 years ago. Although students, volun-teers, and the public benefit greatlyfrom experiences with nature at ACR,our sanctuaries are managed primarilyas natural areas, not parks.

An updated plan for research and resource management at ACR

Beyond Gardening

by John P. Kelly

Figure 1. ACRs Research and Resource Management Program includes projects in conservation

science as well as habitat protection and restoration (HPR) on ACR lands. These areas overlap in

projects that investigate issues in the ecology of restoration or stewardship.

Research and resource management policies

Resource management (natural and human use) zones

Human use impacts

Fire as a management tool

Long-range plan for the Cypress Grove Research Center

Habitat protection and restoration

Herbicide use

Tomales Bay marshes

Toms Point

Bouverie Preserve grasslands

Douglas fir succession

Bolinas Lagoon Preserve outlying properties

Potential scientific investigations of special interest

Potential stewardship projects of special interest

Overview of natural resources at ACR

Key management species

Special status species

Special features

Cultural resources

Guidelines for planting

Table 1. Some topics addressed in the Research and Resource Management Plan of Audubon Canyon Ranch.

ACRresearch

Conservation

science

Natural resources

managementHPR

Ecology ofrestoration and

stewardship


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Second, the RRM Plan indicates thatACR seeks not only to measure how effec-tively we manage natural resources but,

whenever possible, to understand the

underlying ecological effects on nativeplants and animals. This is a serious chal-lenge but one that is inherent in linkingthe long-term protection of our sanctuar-ies with the general conservation crisis.Specifically, the relevance of stewardshipat ACR depends on a scientific approachthat will translate local experience intogeneral guidelines for conservation.

Finally, the stewardship of naturalresources at ACR is strongly influenced byprocesses that operate at scales largerthan our sanctuaries. Great Egrets maytravel far from their natal heronries before

choosing where to nest, and they depend

on prey from surrounding estuariesto feed their young. Invasive weedsexpand across broad ecologicalfronts, invading vulnerable habitatsover whole landscapes and regions.Streams, runoff, and coastal cur-rents transport organisms and

materials, touching everything. Andperhaps as ubiquitous as water arethe effects of humans, which mayimpact our sanctuaries from afar.Its an old epiphanythat every-thing is connectedbut one thatcontinues to inspire responsibleaction. So from this, ACRs RRMPlan recognizes that parallel pro-grams in science, natural areasmanagement, education, and con-servation policy may be necessary to sus-tain the life on our sanctuaries.

Implications of stewardship

Obviously, the themes described abovecan lead to a broad and demandingagenda. Over recent years, natural areashave been swamped by an increasingonslaught of invasive pest species that,like an enormous wildfire, is difficult tocontrol. We take heart in incremental suc-cesses, like the removal of iceplant fromthe beaches of Toms Point on TomalesBay, the restoration of native groundcover along the creek in VolunteerCanyon, and the reestablishment ofnative oaks at Bouverie Preserve.

Scientific projects at ACR targetselected issues in conservation biology,such as Dan Gluesenkamps investigationinto the effects of foraging by non-native

Wild Turkeys on forest-floor organisms(Ardeid 2003). Other projects have investi-gated the regional status, home ranges,and predatory behaviors of ravens (Ardeid20012004); the hydro-geomorphology ofdeveloping tidal marshes (Ardeid 2001,2004); and the influence of freshwaterinflow and tidal circulation on shorebirduse of estuaries (Ardeid 2001).

Natural resources agencies often use

the results of ACR research to assess andmanage heronries, coastal lagoons andmarshes, recreation areas, and other nat-ural areas beyond our boundaries. In fact,the protection (or loss) of naturalresources in other parts of the landscapeprobably influences the life in our sanctu-aries more dramatically than many of ouron-site stewardship activities do. Becauseof such influences, ACR biologists addressregional conservation issues and main-tain active roles in watershed manage-ment councils, conservation planningteams, and technical advisory groups.

Natures laboratories

One increasingly valuable use of pro-tected lands is to provide natural labora-

tories for conservation research.Advanced students and visiting scientistsare showing a growing interest in theundisturbed natural areas of ACR (Ardeid2003). We generally host 10-30 active fieldstudies, addressing topics ranging fromcoastal prairie restoration ecology, toindicators of estuarine health, to theeffects of vineyards on habitat values forbirds. By providing places to investigateundisturbed natural systems, ACR landshave become important resources in con-servation science. However, to protectthese natural values we carefully limit the

number of and types of investigations.

HPR

Habitat Protection and Restoration(HPR) has become a rallying call foractive stewardship at ACR. The HPRProgram, led by Dan Gluesenkamp, tar-gets problems that directly threaten oursanctuaries, by implementing projectsdesigned to understand as well as treatproblems in ecological management(Table 2). With this approach, HPR is anessential part of ACRs overall scientificprogram (Figure 1).

The results of HPR investigations, suchas the evaluation of methods for control-ling invasions of aggressive, non-nativeErharta erecta grass (seeArdeid 2004),contribute to general solutions in restora-tion ecology. HPR activities bring individ-uals and organizations together on proj-ects that combine science, restoration,and educational outreach. Because well-understood solutions for practical prob-lems are often not available, HPR projectsfrequently use adaptive designs, withexperimental methods and incrementalassessments that can be used to redirect

management strategies.

Table 2. Habitat protection and restoration

goals at Audubon Canyon Ranch.

Identify, inventory, map, and monitorspecies populations of concern onACR lands, including rare or special-status species, species ofmanagement concern, and invasivepest species.

Assess the impacts of non-nativespecies on ACR lands.

Organize hands-on volunteeractivities and administer activeconservation efforts and hands-onvolunteer activities to protect andrestore natural resources on ACRlands, including the removal of non-native species and the restoration ofnative species populations.

Conduct applied conservationresearch and publish scientific resultsthat directly promote the protectionor restoration of natural resources onACR lands and surroundinglandscapes.

Contribute to regional conservationefforts and collaborate with naturalresource agencies and landmanagers to mit igate for thenegative effects of invasive species.Of particular importance arewatersheds of Sonoma and Stuart

creeks, Tomales Bay, and BolinasLagoon.

Provide scientific leadership ininteragency research andconservation programs at local,regional, and state levels.

Volunteers pull iceplant to help ACR restore salt marsh

vegetation at Toms Point.


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able to regenerate and persist in theabsence of disturbance. Regional firesuppression as well as catastrophic wild-land fires will continue to influence thepatterns of life on ACR sanctuaries andsurrounding lands. The RRM Planaddresses the role of natural fire in struc-

turing California landscapes and detailsthe potential benefits of using controlledfire to manage natural areas.

The prescribed use of fire can pro-mote natural fire cycles and maintainnatural landscape patterns. Fire can alsobe used to meet specific managementobjectivesto restore habitat patches,enhance local diversity, or control inva-sive weeds. The RRM Plan provides atemplate for the complicated process ofplanning and preparing for a controlledburn. Although ACR has no current plansfor using prescribed fire, the potential

benefits for restoring some areas, such asthe native coastal prairie borderingTomales Bay, are considerable.

Cypress Grove Research Cent er

The diverse challenges set forth in theRRM Plan create great hope for theexpanding role of ACR as a conservationorganization. The long-range strategy for

ACRs Research and Resource Manage-ment Program, headquartered at theCypress Grove Research Center (CGRC)on Tomales Bay, focuses on four programareas: (1) wetlands ecology; (2) restora-

tion and stewardship ecology; (3) ecol-ogy of bird populations, habitats, andbehavior; and (4) conservation ecologyof herons and egrets. The first two areasrepresent appropriate unifying themesfor future work, based on the dominanceof wetland issues in regional conserva-tion and the importance of remnantnative habitats in surrounding (urban-ized) landscapes. ACR plans to developadditional staff expertise in wetlands andlandscape ecology and to enhance officespace, guest housing, and laboratoryfacilities at CGRC.

It takes more than a good barn and awell-equipped tool shed to care for thenatural character of the land. The depthof local knowledge, extent of hands-onactivity, and level of scientific expertiseneeded for such work can be consider-ableespecially if responsible steward-ship is viewed as a practice embeddedin the surrounding ecological andsocial/ political landscape. Such a per-spective presents a huge challenge, butone that ACRs RRM Plan considers to beessential.

reproduction are also evident. For exam-ple, Great Egrets produce slightly (but sig-nificantly) more young per nest, on aver-age( standard error), in the Suisun Marsh

area (2.2 0.02 young per nest) than in thePetaluma/Napa marshes (1.9 0.03), theOuter Marin/Sonoma Coast (2.0 0.02), orthe Russian River/ Laguna de Santa Rosa(2.0 0.02).

On a local scale, particular colonies ofGreat Blue Herons consistently outper-form other colonies. Such a pattern is evi-dent at the DeSilva Island heronry inMarin County where successful nests pro-duce an average of 2.4 0.10 young com-pared to only 2.05 0.03 young elsewherein the region. Understanding such differ-ences may provide insights into the eco-

logical processes affecting feeding andnesting areas.

Regional patterns in nest survival(chance of successfully fledging at leastone young) are less evident. This isbecause the geography of nest failureseems to vary among years. Nest failurerates are normally low for Great BlueHerons (21 1.4%, n = 342) and GreatEgrets (22 2.2%, n = 143), but cata-strophic colony failures of more than 90percent occur at one or more heronriesin most (75%) survey years. These eventsare usually the result of human distur-

bance or intense predation by eagles,ravens, or other nest predators, and canapparently occur anywhere in the region.So, like earthquakes and fires, cata-strophic losses to predators or distur-bance are difficult to predict. At one sitein Suisun Marsh, a tree full of nests withdeveloping young simply toppled into aslough.

The regional heron and egret atlasmarks a new beginning for ACR research.Plans are now underway to enhance theunderlying database to help in under-standing how herons and egrets respond

to changes in wetland quality. We aredeveloping additional studies on forag-ing activities, flight patterns, and habitatpreferences. By viewing the activities ofnesting herons and egrets as an ecosys-tem process, we hope to find new waysto understand their wetland habitats. Weare inspired by this approach because, ofcourse, their wetlands are also ours.


An effective HPR program must con-duct ongoing reconnaissance, as well asdesign and implement projects thatreduce threats to local resources. With somany potential problems, this is nevereasy. However, standardizing stewardshipprocedures can reduce the likelihood of

new threats. For example, the RRM Planincludes guidelines for planting that facil-itate appropriate revegetation of dam-aged sites. Such standards protect nativesystems by guarding against the introduc-tion of invasive plant species, avoidingadverse impacts to pollination systems,and preserving the genetic integrity ofnative plants on ACR lands. Routine pro-cedures for cleaning the cutting blades ofhand tools and washing down truck ortractor tires when returning from otherlocations help limit the introduction ofinvasive weeds as well as environmental

pathogens such as Sudden Oak Death.

Rapid response

One objective of the RRM Plan is todevelop a rapid-response procedure that

will allow more effective management ofecological emergencies. What constitutesan ecological emergency? Consider thescattered colonization over a large area byan aggressive non-native pest plant (suchas yellow star thistle), the discovery of anextremely rare species, or the catastrophicimpacts of an oil or chemical spill. Rapidresponse may involve hiring specialists or

laborers, conducting ad-hoc surveys, orusing unusual means to avoid cata-strophic habitat loss or debilitating man-agement problems.

ACR strongly avoids the use of herbi-cides, preferring more expensive, manualmethods to fight invasions of non-nativeSpartina (cord grass) in western MarinCounty marshes (Ardeid 2002) or toremove Elytrigia pontia, an invasive non-native perennial grass that smothers sea-sonal wetlands at Bouverie Preserve.However, under unusual circumstances,the careful, stitch-in-time use of herbi-

cide may provide the only feasible way toprevent an ecological disaster.

Natural fire

Most ecosystems in California haveevolved under periodic disturbance byfire (seeArdeid 2001). Other natural dis-turbances include windstorms, land-slides, and floods. Natural levels of dis-turbance contribute to biological diver-sity by creating conditions suitable forspecies that thrive under various stagesof post-disturbance recovery, while otherareas maintain more stable conditions

suitable for species that are long-lived or

Heron Atlas, from page 3


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California Coastal Conservancy to con-duct a watershed assessment of Bear

Valley Creek that will address this ques-tion. The primary purpose of the study

is to increase spawning and rearinghabitat for salmonids in the CentralCalifornia Coast Evolutionary SignificantUnit. The study will identify actions toimprove landscape connectivitybetween Bear Valley Creek, OlemaMarsh and Tomales Bay and will proba-bly recommend repairing culverts andstream crossings that limit fish passagebetween Tomales Bay and the Bear

Valley watershed.

ACRs Plan for Olema Marsh

ACRs primary goal for Olema Marsh

is to promote natural wetland processesthat will improve and maintain habitat

Olema Marsh, from page 5


for breeding and wintering marsh birds,particularly passerines, rails, and shore-birds. Special consideration is given tothe requirements of the California BlackRail, Virginia Rail, Sora, migrant fresh-

water shorebirds, Marsh Wren, Red-winged Blackbird, Tri-colored Blackbird,

and Salt Marsh Common Yellowthroat.To accomplish these objectives, man-agement efforts will focus on restoringhydrologic circulation that will sustain avariety of riparian and marsh vegeta-tion. ACR also recognizes the impor-tance of enhancing wetland habitat val-ues that benefit a variety of other nativeand special-status species, includingsalmonids, tidewater goby, Californiared-legged frog, northwestern pond tur-tle, San Francisco forktail damselfly,California freshwater shrimp, andsouthwestern river otter.

ACR will continue to take an activerole in the restoration and protection of

our sanctuaries and looks forward tosuccessful collaboration with managersof adjacent land. Such collaboration isessential to protect natural ecologicalprocesses throughout the local land-scape. Through these and other efforts,

we can set a good example for improv-

ing stewardship at larger scalesrequired to sustain native plant andanimal populations.

References cited:Avocet Research Associates. 2003. Giacomini

Marsh Restoration Site special status animalspecies: Reconnaissance and compliance.Report to the National Park Service.

Evens, J. G. and R.W. Stallcup. 1985. The 1984monitoring season at Olema Marsh, MarinCounty, CA.; ACR. Technical Report #85-1-1.

Evens, J. G. and R.W Stallcup. 1991-1994. Annualbreeding bird censuses: Journal of FieldOrnithology. 62-65 (Suppl).

Kelly, J.P. and C. Wood. 1996. Diurnal, intrasea-

sonal, and intersexual variation in foragingbehavior of the Common Yellowthroat. TheCondor 98: 491-500.

Effects of invasive species on nitrogenretention and other issues in the ecologyand restoration of coastal prairie. JeffCorbin and Carla dAntonio, UC Berkeley.

Species diversity, rare plant persistence,and parasitism in mid-Pacific coast saltmarshes: functional significance ofinterplant parasitism. Brenda Grewell, UCDavis.

Effects of dispersal on insect populationdynamics and parasitoid diversity in gallsofRhopalomyia californica onBaccharispilularis. Martha Hoopes and CherylBriggs, UC Berkeley.

Multi-scaled vegetation data to predictwildlife species distributions using awildlife habitat relationship model.Jennifer Shulzitski, USGS Golden Gate

Field Station.Impact of butterfly gardens on pipevineswallowtail populations. Jacqueline Levy,San Francisco State University.

The effect of landscape changes on nativebee fauna and pollination of native plantsin Napa and Sonoma counties. GretchenLeBuhn, San Francisco State University.

Ecological indicators in West Coastestuaries. Steven Morgan, SusanAnderson, and others, UC Davis BodegaMarine Lab, UC Santa Barbara.

Consequences of species invasion underglobal climate change. Elizabeth Brusati,UC Davis.

Long-term monitoring of the Giacominiwetland. Lorraine Parsons, Point ReyesNational Seashore.

Factors causing summer mortality inPacific oysters. Fred Griffin, UC DavisBodega Marine Lab.

Effects of Sudden Oak Death onwoodland vegetation structure. LettyBrown, UC Berkeley.

Effects of SOD-induced habitat change onvertebrate communities. Kyle Apigian andDon Dahlson, UC Berkeley.

The different ial ability of annual andperennial grasslands in California by a non-

indigenous invader, Foeniculum vulgare.Joel Abraham and Jeff Corbin, UBBerkeley.

Differences in arthropod communitycomposition in native and exoticdominated grasslands. Natalie Robinson,UC Berkeley.

A comparison of carbon cycling andmaterial exchange in grasslandsdominated by native and exotic grasses innorthern California. Laurie Koteen, UCBerkeley.

Black Brant counts at Drakes Estero,Tomales Bay and Bodega Bay. Rod Hug,Santa Rosa, CA.

Monitoring avian productivity andsurvivorship (MAPS) station at LivermoreMarsh. Denise Jones, Institute for BirdPopulations.

Strophariaceae of California. Peter Werner,Dennis Desjardin, San Francisco StateUniversity.

Reintroduction ofStellaria littoralis to thePresidio. Lewis Stringer, Golden GateNational Recreation Area.

Bouverie Preserve amphibian study. DavidCook, Santa Rosa, CA.

Surface water ambient monitoringprogram: south coastal Marin and San

Francisco surface water quality study.Karen Taberski, San Francisco RegionalWater Quality Control Board.

Tomales Bay harbor seal monitoring. MaryEllen King, Santa Rosa, CA.

Effects of landscape context andrecreational use on carnivores in northernCalifornia. Sara Reed, UC Berkeley.

Effects of macroalgal bloom on seagrassbed product ivity in Tomales Bay. BrittanyHuffington, San Francisco StateUniversity.

Visiting investigators


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Picher Canyon Heron andEgret Project The fates ofall nesting attempts at ACRsPicher Canyon heronry have

been monitored annually 1967to track long-term variation innesting behavior andreproduction.

Livermore M arsh AsACRs Livermore Marsh, onTomales Bay, transforms froma freshwater system into atidal salt marsh, we arecompleting a study of therelationship between increas-ing tidal prism and marsh channeldevelopment. M onitoring ofwinter and breeding bird usebegan in 1985. The data will be

linked to measurements ofvegetation to reveal changesassociated with the developingtidal marsh. We also monitorthe depth and duration ofground water which stronglyinfluences biological conditionsin the upper marsh.

Tomales Bay ShorebirdProject Since 1989, wehave conducted annualshorebird censuses onTomales Bay. Each censusinvolves six baywide w intercounts and one baywide counteach in August and Aprilmigration periods. A team of15-20 volunteer field observersis needed to conduct eachcount. The data are used toinvestigate winter populationpatterns of shorebirds, localhabitat values, andconservation implications.

Tomales Bay WaterbirdSurvey Since 198990,teams of 1215 observershave conducted w interwaterbird censuses fromsurvey boats on Tomales Bay.The results provide informationon habitat values andconservation needs of 51species, totaling up to 25,000birds. Future work will focuson trends and determinants ofwaterbird variation on TomalesBay.

North Bay Counties Heronand Egret Project Annualmonitoring of reproductiveactivities at all known heronand egret nesting colonies infive northern Bay Area

counties began in 1990. The

In progress:project updates

data are used to examineregional patterns of repro-ductive performance, distur-bance, habitat use, seasonaltiming and spatial relationshipsamong heronries. The projecthas been incorporated into theIntegrated Regional Wetland

Monitoring (IRWM) program, aCALFED project to developregional monitoring for SanFrancisco Bay. An annotatedregional atlas of heronries is inpreparation. Based on thiswork, we are collaborating w ithother scientists and wetlandmanagers on the developmentof the California WaterbirdConservation Plan.

Common Ravens inheronries We have beenobserving and radio-trackingnesting ravens in Marin Countyand measuring their predatorybehaviors in heron and egretnesting colonies. We haveproduced scientific papers onthe status of ravens and crowsin the San Francisco Bay area,on home range use, and onraven predatory behaviors.Future work will addressdiurnal movements of ravens,methods in radio telemetry,and techniques for managingraven predation.

Impacts of Wild Turkeys

on forest ecosystems

Invasive, non-native WildTurkeys are common atBouverie Preserve andthroughout most of SonomaCounty. The goal of this studyis to experimentally measurethe effects of ground foragingby Wild Turkeys on vegetation,invertebrates, and herpeto-fauna in the forest ecosystemof Bouverie Preserve. Theresults will provide informationthat can be used by agenciesto improve management andcontrol of turkey populations.

Ehrharta erectamanagement andresearch Ehrharta erectaisa highly invasive perennialgrass native to South Africa. Itis currently invading westMarin County and is abundantin ACRs Pike County Gulch.The goals of this project are tounderstand the effects ofEhrharta invasion, developtools for control of Ehrharta,and restore habitat invaded byEhrhartaat Bolinas LagoonPreserve.

Plant species inventory Resident biologists maintaininventories of plant speciesknown to occur on ACRsTomales Bay properties and atBouverie and Bolinas Lagoonpreserves.

Cape ivy control,Volunteer Canyon Manualremoval has proven to be verysuccessful in reducingnonnative cape ivy from theriparian vegetation in ACRsVolunteer Canyon. Continuedvigilance in weeded areas hasbeen important, to combatresprouts of black nightshade,Vinca, and Japanese hedgeparsley.

Annual surveys andremoval of non-nativeSpartinaand hybrids

Protection of ACRs shorelineproperties from invasion bynonnative Spartinais critical tothe protection of ACR landsand provides a critical contri-bution to the overall monitoringand management of TomalesBay and Bolinas Lagoon. Inaddition to conducting surveyson ACR lands, Katie Etienne iscollaborating on surveys ofother shoreline properties inthese estuaries.

Influence of terrestrialinvertebrates on

grasslands This project willdetermine whether thedominance of European plantspecies in grasslands at theBouverie Preserve is caused byherbivory by two types ofground-dwelling invertebrates:African earwigs (Emborelliacincticollis) and European slugs(Deroceriussp.).

Vernal wetland botanicalsurveys at BouveriePreserve As part of ACRseffort to determine theecological values of vernal

wetlands at Bouverie Preserve,Ramona Robison conducted afloristic survey designed totarget rare plants. The surveysprovided plant species lists,vegetation cover values, andGPS delineation of wetlandhabitats and locations of rareplants.

Salt m arsh ice plantremoval Non-native iceplant is being removed frommarshes and upland edges atToms Point on Tomales Bay,using manual removal, shadingwith black plastic, andglyphosate.

Eradication of Elytrigiaponticaspp. ponticaElytrigiais an invasive, non-native perennial grass thatforms dense populations inseasonal wetland sites. AtBouverie Preserve, we areusing manual removal bygroups of volunteers, lightstarvation and solarizationusing black plastic tarps), andglyphosate spot treatments toremove outlier and moderatesize patches of Elytrigia.

Nest boxes Rich Stallcuphas installed and maintainsseveral Wood Duck nest boxesalong Bear Valley Creek inACRs Olema Marsh. TonyGilbert has installed andmaintains Western Bluebirdnest boxes in the CypressGrove grasslands.

Eucalyptus removal Eucalyptus t rees are beingremoved with incrementalannual cutting from BouveriePreserve.

Restoration of coastaldunes by removal ofAmmophila arenariaAmmophila arenariais a highlyinvasive, non-native plant thatalters the topography andfunction of coastal dunes. Thisproject is restoring importantdune habitat at ACRs TomsPoint and protecting manynative species that depend onthe dynamic conditions foundin mobile dunes.

Douglas fir control in oakwoodland We are

removing seedling and saplingDouglas fir trees at BouveriePreserve to protect existingoak woodland habitat fromencroachment and conversionto Douglas fir forest.

Grazing of Bouveriegrasslands A prescribedgrazing program has beenimplemented to maintain orincrease the abundance ofnative grassland plant speciesand to protect the vernalwetlands at Bouverie Preserve



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Ardeid (Ar-DEE-id), n., refers to

any member of the family

Ardeidae, which includes herons,

egrets, and bitterns.

The Ardeid is published annually by Audubon Canyon Ranch as an offering to field

observers, volunteers, and supporters of ACR Research and Resource Management.

To receive The Ardeid, please call or write to the Cypress Grove Research Center.

Subscriptions are available free of charge; however, contributions are gratefully

accepted. 2005 Audubon Canyon Ranch. Printed on recycled paper.

Managing Editor, John Kelly. Layout design by Claire Peaslee.

AUDUBON CANYON RANCH IS A SYSTEM OF WILDLIFE SANCTUARIES

AND CENTERS FOR NATURE EDUCATION

BOLINAS LAGOON PRESERVE CYPRESS GROVE RESEARCH CENTER BOUVERIE PRESERVE

the

Ardeid

Research

and Resource

Management at

Audubon Canyon Ranch

Audubon Canyon Ranch

4900 Shoreline Hwy., Stinson Beach, CA 94970

Cypress Grove Research Center

P.O. Box 808

Marshall,CA 94940(415) 663-8203

Nonprofit Org.

U.S. Postage

PAID

Permit No. 2

Stinson Beach, CA

Protecting Rarities see page 6

ACR stewardship encompasses such rare plant

species as dune gilia at Toms Point.

DANIELGLU

ESENKAMP

the ardeid newsletter, 2005 ~ audubon canyon ranch

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