The Ardeid Newsletter, 2001 ~ Audubon Canyon Ranch

8/9/2019 The Ardeid Newsletter, 2001 ~ Audubon Canyon Ranch

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Vernal pools and

swales the

ecosystem

perspective

Fire as a

management tool

a re.examination

Dunlin in winter

energy in the

balance Ravens

and crows a

population

report Tidal marsh

progress watershed

effects Research

project updates

2 0 01

the

Ardeid

Research and

Resource M anagement

at Audubon Canyon Ranch


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Audubon Canyon Ranch

Research and ResourceManagement

Executive Staf f

Skip Schwartz, Executive DirectorJohn Petersen,Associate Director

Staff Biologists

John Kelly, Ph.D., Director, Research & ResourceManagement

Rebecca Anderson-Jones, Bouverie PreserveGreg deNevers, Bolinas Lagoon PreserveKatie Etienne, Research Coordinator

Land Stewards

Bill Arthur, Bolinas Lagoon PreserveDavid Greene, Tomales Bay properties

John Martin, Bouverie PreserveField Biologists

Jill AwkermanAviva BarskyEllen BlusteinRebecca DymzarovLauren HammackMark McCaustlandEric Punkay

Research A ssociates

Jules EvensGrant FletcherRachel KammanFlora MacliseHelen PrattRich Stallcup

Resource M anagement Associates

Len BluminRoberta Downey

Scientific A dvisory Panel

Sarah Allen, Ph.D.Peter Connors, Ph.D.Jules EvensKent Julin, Ph.D.Greg KammanRachel KammanChris Kjeldsen, Ph.D.Doug Oman, Ph.D.Helen PrattW. David ShufordRich Stallcup

Wesley W. Weathers, Ph.D.

the ARDEID 2001

The following list includes ACR field observers and habitatrestoration volunteers since the previousArdeid. Please call(415) 663-8203 if your name should have been included in this list.

PROJECT CLASSIFICATIONS:

B = Breeding Birds at Bouverie Preserve x C = Common Raven Study x

H = Heron/Egret Project x I = Plant Species Inventories x M = Livermore

Marsh Monitoring x N = Newt Survey x P = Photo Points x R = Habitat

Restoration x S = Tomales Bay Shorebird Project x W= Tomales Bay

Waterbird Census

The Watch

Dawn Adams (HS); Sarah Allen (S);Audubon Canyon Ranch Juniper Club(N); Bob Baez (SW); Norah Bain (H);Tom Baty (W); Chaz Benedict (H);Gordon Bennett (S); Peter Bergen (R);

Louise Bielfelt (N); Sherm Bielfelt (N);Gay Bishop (S); Julie Blumenthal (W);Len Blumin (R); Patti Blumin (HR);Ellen Blustein (M); Noelle Bon (HN);Milissa Booker (H); Janet Bosshard(HS); Elaine Boston (H); WoodyBoston (H); Maureen Bourbin (H);Bryan Brandow (R); Emily Brockman(HSW); Ken Burton (SW); DeniseCadman (H); Barbara Carlson (N); BillCarlson (N); Kate Carolan (S); AnnCassidy (H); Catherine Caufield (W);Caeser Chavez Elementary School -two 5th Grade classes from Richmond(R); Hugh Cotter (W); Rig Currie (S);Nick Degenhardt (HR); Carolyn Dixon(H); Roberta Downey (R); Joe Drennan(W); David Easton (H); LewEdmondson (H); Marilyn Edmondson

(H); Ted Elliot (H); Field Etienne (W);Bob Evans (H); Jules Evens (SW);Cathy Evangelista (H); Katie Fehring(SW); David Ferrera (W); BinnyFischer (H); Grant Fletcher (HPSW);Ginny Fletcher (HPS); James Fossum(N); Carol Fraker (H); Kathy Francone(H); Dan Froehlich (SW); Harry Fuller(SW); Tony Gilbert (W); Beryl Glitz(H); Dohn Glitz (H); Ellen Goldstone(N); Philip Greene (H); JudyGruenwald (H); Madelon Halpern (H);Paul Hansen (W); David Hastings (W);Shelly Hatleberg (H); Diane Hichwa(BH); Edna Hickok (H); Jeri Jacobson(H); Gail Kabat (W); Lynnette Kahn(HS); Guy Kay (H); Carol Keiper (HS);Shane Kelly (H); Marion Kirby (N);

Richard Kirschman (SW); Ellen Krebs

(H); Carol Kuelper (SW); Alexis Lee(H); Tom Lee (S); Laura Leek (W); GailLester (W); Keith Lester (W); RobinLeong (H); Eileen Libby (H); EricLichtwardt (H); Dee Dee Long (W);

Flora Maclise (H); Art Magill (R); LynMagill (R); Jo Maillard (H); MichelleManos (H); Roger Marlowe (W); AmyMc Andrews (S); Chris Mc Auliffe (H);Mark Mc Caustland (HS); Coleman McClelland (N); Julie Mc Clelland (N); PatMclorie (N); Nicole Michel (HSW); SitaMulligan (W); Jean Miller (H); IanMorrison (W); Marty Morrow (H); DanMurphy (W); Karen Nagle (BH); WallyNeville (H); Terry Nordbye (SW); HalOber (S); Mathew Ober (S); BeckyOlsen (H); Richard Panzer (H);Patagonia employees (R); Ray Paula(H); Karen Paull (W); Kathy Peterlein(S); Myrlee Potosnak (H); Grace Pratt(N); Jeff Reichel (H); Linda Reichel (H);Rudi Richardson (W); Cheryl Riley (H);Glenda Ross (R); Ellen Sabine (H); Carl

Sanders (HW); Don Sanders (H);Marilyn Sanders (H); Fran Scarlett (H);Becky Scotts 3rd Grade class fromBolinas (R); Craig Scott (W); ClaireShurvinton (H); Sierra Club Outings(R); Ann Smith (H); Duane Smith (H);Joe Smith (HW); Anne Spencer (S);Rich Stallcup (S); Jean Starkweather(H); Michael Stevenson (SW); JamaicaSuk (N); Lowell Sykes (SW); JudyTemko (HS); Paula Terrey (H); JanetThiessen (HW); Gil Thomson (H);Wayne Thompson (W); James Titus(N); Susan Van Der Wal (H); TanisWalters (S); Ralph Webb (H); RosalieWebb (H); Diane Williams (S); BillWilson (S); Ken Wilson (HW); JonWinter (H).

In this issue

Vernal Pools and Swales at the Bouverie Preserve: Developing an ecosystem

perspective for seasonal wetland management by Rebecca Anderson-Jones....................page 1

Balancing Acts: Energy conservation in wintering Dunlin by John P. Kelly ........................page 4

Marsh Revival: Monitoring the return of tidal influence on a coastal wetland

by Katie Etienne ......................................................................................................................page 6

The Birds: Abundance and distribution of Common Raven and American Crow

in the San Francisco Bay area by John P. Kelly ....................................................................page 8

Must We Have Fire? The ecological history and role of fire in ACR management

by Greg deNevers ....................................................................................................................page 10

In Progress: Project updates ................................................................................................page 13

Cover photo: Dunlin flock by T. Fitzharris VIREO


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2001 the ARDEID page 1

Once regarded as littlemore than mudholes or hog wal-

lows, vernal pools andswales are now widely rec-ognized as intrinsicallyvaluable features of thebroader ecological land-scape. Yet these ephemeral

wetlands present manychallenges to the conserva-tion land manager. Foundacross much of California,vernal pools and swaleshold water through the

winter and spring seasons,providing habitat forspecies that occur nowhereelse. Vernal pool topogra-phy is often mounded orrolling, with pools formingin the depressions betweenelevated areas known as

mima mounds. Somemima mounds rise onlyinches above the nearestpool floor, while others may be muchtaller, measuring to a height of six feet.

Adjacent pools are sometimes linked by aseries of natural channels or swales. Ahardpan underlying the soil restricts

water percolation, producing saturatedsurface soils and prolonged inundationfor the species that inhabit these depres-sions. Some species that depend on thesehabitats have been assigned special con-servation status, including a host of flow-

ering plants, amphibians, and inverte-brates adapted to the harsh transitionfrom inundation to desiccation thatoccurs as vernal pools and swales fill anddry. As we continue to study the poolsand swales at the Bouverie Preserve, wedo so with the awareness that an effectivemanagement strategy must take intoaccount the characteristics that make thisecosystem unique.

Along the western boundary of theBouverie Preserve, near Glen Ellen in the

Valley of the Moon, seasonal wetlandsencompass three interconnecting swales

and two discrete vernal pools in a land-scape dominated by native and intro-duced grasses and forbs. Subtle changesin elevation characterize the topography,

with low mounds separating the nearlyparallel swales distal from Highway 12.

Adjacent to the highway, these swalesconverge into a broader perpendiculardepression. A well-established oak plant-ing project that also exists in this field,once managed exclusively as pasture,

recreates features of an oak savannah thatmay have occurred on this site beforeagricultural use. In the regional parkacross the highway, yellow rings ofSonoma sunshine (Blennosperma bakeri),an endangered member of the sunflowerfamily, demarcate a few small vernalpools. Similar patterns of color occur inthe vernal wetlands at Bouverie in thespring (see photo). Although the historicrelationship between the vernal wetlandsat Bouverie Preserve and the vernal poolsin the regional park is unclear, both sys-tems lie within an area conservation plan-

ners describe as the Santa Rosa VernalPool Region (Keeler-Wolf et al. 1998.California vernal pool assessment. Prelim.Rpt. Calif. Dept. Fish and Game.).

The Santa Rosa Vernal Pool Regionextends south from the Russian Riverinto northern Marin County and easttoward Sonoma, and it is comprised ofmany vernal wetland systems. Some ofthese pools contain state and federallyrecognized endangered endemics such as

Burkes goldfields (Lasthenbia burkei),Sebastopol meadowfoam (Limnanthesvinculans), and Sonoma sunshine. Manyvernal pools and swales in the regionhave succumbed to, or are threatened by,changes caused primarily by humanactivity, including urban and agriculturalexpansion, the spread of nonnative, inva-sive plants, poor grazing managementpractices, altered hydrology due to irriga-tion, increased foot traffic, discing dam-age, and other disturbances.

Although vernal wetlands share manyphysical characteristics, the species com-

Developing an ecosystem perspective for seasonal wetland management

Vernal Pools and Swales

at the Bouverie Preserveby Rebecca Anderson-Jones

Southernmost vernal pool at Bouverie Preserve, near Highway 12; March, 2001.

Continued on page 2


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position of vernal pools and swales canvary significantly across landscapes andeven between adjacent pools and swalesin the same system. An expanded inven-tory of the plants, invertebrates, andamphibians as well as hydrologic and geo-logic profiles will be developed for thepools and swales at the Bouverie Preserve.This information will be used as we devel-op a new grassland management plan

incorporating wetland conservation goals.Data regarding species composition of

the Bouverie Preserve wetlands are cur-rently limited to a partial flora compiledfrom occasional, informal surveys of thepools, swales and adjacent uplands by

ACR volunteer and staff botanists PhyllisEllman, Grant Fletcher, Greg deNevers,and Rebecca Anderson-Jones. This list(Table 1) includes many wetland indica-tor species such as coyote thistle, iris-leaved rush, meadowfoam, and tiny glueseed, a common relative of the endan-gered composite found across the road. A

few nonnative and potentially invasivewetland weeds also thrive here. Penny-royal is found here and also in ditchesand wet depressions bordering agricultur-al lands elsewhere in Sonoma and Marincounties, in vernal pools and meadows inthe Laguna de Santa Rosa floodplain,along the edges of the Estero Americano,and along the banks of the PetalumaRiver. Velvet grass is an invasive, intro-duced perennial grass that competes withpennyroyal as well as with native wetlandvegetation along the eastern margin ofthe swales here, and it is common in

on the indigenous floraand the hydrology of sea-sonal wetlands and theuplands associated withthem (Barry 1998, in

Witham et al., eds. 1998.Ecology, conservation, and

management of vernalpool ecosystems. Proc.1996 CNPS Conf.).

Ideally, to manage ver-nal wetlands in a grasslanddominated by introducedannuals, one would begina light grazing regime earlyin the year. This wouldprevent the build-up ofexcessive biomass, easethe competitive pressurefor many native plants,and keep some of the most

noxious invasive annualgrasses, such as medusa-head, from setting seed.However, the presence of

grazing animals can adversely affectground-nesting birds in the adjacentuplands, and this has been a concern atthe Bouverie Preserve. Here, Red-wingedBlackbirds typically breed and nest in thetall grasses and forbs near the vernalpools and swales from the end ofFebruary through early May. To avoid dis-rupting the birds at this crucial time, a

moist coastal and inland fields. The intro-duced hyssop-leaved loosestrife is a lessinvasive congener of the infamous purpleloosestrife, a plant that has created signif-icant management problems in theSacramento Delta and other waterwaysthroughout the state.

Managing a unique system

Left unchecked, many nonnative

plants, including grasses such asvelvet grass and medusahead, and

forbs such as those described above canpose significant threats to vernal poolecosystems. These threats include directdisplacement of native plants along pooland swale margins, as well as displace-ment of native vegetation in the centersof pools and swales during dry years. Inaddition, introduced annual grasses drainsoil moisture earlier in the growing sea-son than their perennial native counter-parts, and they produce large quantitiesof thatch that can accumulate, decreasing

runoff. Both of these effects give intro-duced annual grasses the potential to sig-nificantly alter the hydrologic profile ofthe landscape. In addition, the accumula-tion of thatch from annual grasses canlimit light penetration, decreasing thecompetitive success of many nativeplants. Although long-term intensivegrazing has been associated with thedecline of floristic quality in many ver-nal pools across the state (Keeler-Wolf etal. 1998), carefully managed grazing isalso recognized as a valuable strategy forreducing the impacts of nonnative grasses

Vernal swale at Bouverie facing west; March, 2001. In the foreground, the flowering stalks of velvet grass, Holcus lanatus, an

invasive, nonnative grass at the east end of the swale. In the center of the picture, a vernal swale is bordered by light bands offlowering Limnanthes douglasii. In the left background, the entrance driveway across the highway leads to the Sonoma Valley

Regional Park, where the endangered Blennosperma bakerigrows in vernal pools.

Close-up from the east end of the central swale;

March 2001. Three competing species: Limnanthes

douglasii, a native meadowfoam in the foreground,

Mentha pulegium; the creeping, invasive, nonnative

pennyroyal above that; and the invasive, nonnative

velvet grass, Holcus lanatus, in the background.

page 2 the ARDEID 2001

x Vernal pools, continued

PHOTOSBYREBECCAANDERSON-JONES


5/16


long-term grazing regime was imple-mented years ago that began in latespring and continued through the sum-mer months. However, after upland grass-es dried and became significantly lesspalatable, vernal pool and swale plantsremained moist. As a result, certain wet-

land plants were preferentially grazed latein the season, and some areas of theswales were eventually overgrazed.

Grazing can create other managementchallenges as well. Where grazing pres-sures are intense, the least palatable andoften less desirable species, like medusa-head, pennyroyal, or turkey mullein(Eremocarpus setigerus), may becomedominant. For this reason, monitoringcan be an important component of a veg-

etation management project that relies ongrazing. An additional consideration isthe effect of nitrogen enrichment wherelivestock graze. The impact of nutrientenrichment on vernal pool and swalespecies is uncertain, although concernshave been raised that resulting biotic

changes, including algal blooms, couldhave a detrimental effect on some vernalpool plants, including the endangeredContra Costa goldfields (Lasthenia conju-gens; Ornduff 1995, in Dept. of Int. U.S.Fish and Wildlife Final Rule, Endangeredstatus for four plants from vernal poolsand mesic areas in northern California.Fed. Reg. June 18, 1997). Land managersat Jepson Prairie in Solano County, havetested a combination of early season

Table 1. A partial flora of the vernal swales and pools at Bouverie Preserve. OBL = obligate wetland species; almost always occur in wetlands under natural condi-

tions. FACW = usually occur in wetlands but occasionally found in other areas. FACU = usually occur in non-wetlands but occasionally found in wetlands. Where

two categories have been applied, species, ecotypes or subspecies vary in response to wetland habitat requirements. * Indicates introduced species. Indicator cat-egories derived from the U.S. Fish and Wildlife Service, National List of Vascular Plant Species That Occur in Wetlands: 1998.

Family name Binomial name Common name Indicator category

Apiaceae Eryngiumsp. coyote thistle OBL; FACW

Asteraceae Blennosperma nanum tiny glue seed OBL

Campanulaceae Downingia concolor no comm on name OBL

Crassulaceae Crassula aquatica no comm on name OBL

Cyperaceae Eleocharissp. spike rush OBL; FACW

Juncaceae Juncus bufonius toad rush FACW; OBL

Juncaceae Juncus xiphioides iris-leaved rush OBL

Lamiaceae Mentha pulegium* pennyroyal OBLLiliaceae Triteleia hycinthina white hyacinth FACW

Limnanthaceae Limnanthes alba white meadowfoam OBL

Limnanthaceae Limnanthes douglasii meadowfoam OBL

Lythraceae Lythrum hyssopifolia* loosestrife FACW; OBL

Poaceae Deschampsia danthanioides annual hairgrass FACW

Poaceae Glyceria occidentalis western mannagrass OBL

Poaceae Holcus lanatus* velvet grass FACU; FACW

Poaceae Hordeum brachyantherum meadow barley FACW

Poaceae Pleuropogon californicus semaphore grass OBL

Poaceae Polypogon maritimus* Mediterranean OBL

beardgrassPoaceae Taenicum caput-medusae* medusahead FACU1

Polemoniaceae Navarretia intertexta no common name FACW; OBL

Portulacaceae Montia fontana water chickweed OBL

Primulaceae Centunculus minim us chaffweed OBL; FACW

Ranunculaceae Ranunculus muricata* spiny buttercup FACW

Scrophulariaceae Gratiola ebracteata hedge-hyssop OBL

Scrophulariaceae Mimulus guttatus seep-spring OBLmonkeyflower

Scrophulariaceae Veronica peregrina purslane speedwell OBLssp. xalapensis

1

Adapted from Crampton (1974. Grasses in California, U.C. Press).

grazing and late spring burns to controlmedusahead and manage annual grassbiomass. Their results suggest that firealso has a great deal of potential as a toolfor managing vernal wetland and associ-ated grassland vegetation (Pollak and Tan1998, inWitham et al. 1998).

Managing vernal wetland landscapesto favor native biodiversity is a challengethat requires an informed, creative andadaptive approach. We continue gather-ing information about vernal wetlandmanagement efforts and the BouveriePreserve wetland system, and we look for-ward to developing a management planthat will incorporate strategies for pro-tecting the biotic and hydrologic charac-ter of this unique ecosystem. s


6/16


It is a common understanding in theSan Francisco Bay area that there hasnever been an average winter. That is,

winters vary dramatically in both thecumulative extent and pattern of seasonalrainfall. Even without droughts or floods,rainfall needed to invigorate and sustaincoastal watersheds may be delivered byprolonged periods of gentle precipitationor, alternatively, by a few fierce winterstorms. It seems impossible to predict our

winter weather. Nonetheless, winteringshorebirds must contend with this uncer-

tainty, because rainstorms, wind, extremehigh tides, and pulses of freshwater runoffstrongly influence both thermal and for-aging conditions.

Increases in freshwater runoff cancause estuarine invertebrates to recededeeper into the mud, beyond the reach ofprobing sandpipers. During periods ofheavy runoff, prey populations decline.Strong winds may further alter the behav-iors of prey, reducing their detectability toshorebirds. During severe or extendedstorms, birds may use more energy thanthey can obtain by feeding, increasing

risks of starvation and predation. Suchrisks structure complex adaptations thatunderlie the wonder of these wind birds.

To improve their chances of winter sur-vival, shorebirds maintain energy stores inthe form of fat and protein that can bemobilized to provide fasting enduranceduring periods of extreme cold or food

scarcity. The use ofalternative feedingareas during such timesmay be crucial. In areciprocal translocationof color-banded Dunlin(Calidris alpina) be-tween northern andsouthern Tomales Bay,displaced individualsquickly returned to andremained in the vicinityof their sites of capture.

Thus, under normalwintering conditions,they exhibit a relativelysmall range of movement. However,Dunlin also exhibit non-migratory mid-

winter flights to interior wetlands in theCentral Valley (Warnock et al. 1995. WilsonBulletin 107: 131-139). The timing of theseflights coincides with the seasonal devel-opment of wetlands in the interior, as wellas with deteriorating feeding conditionsalong the coast. So Dunlin may depend onactivity expenditure (regional flight capaci-ty) as well as storage of reserve energy to

adaptively respond to changing risk ofwinter starvation. But what adaptive wis-dom guides how these birds choosebetween storing and using energy?

Storing energy in reserve body tissueinvolves a trade-off between the costsand benefits of fattening (Figure 1).

Although storing fat reduces starvationrisk, the associ-ated gain inbody massincreases thecost of flightand reduces a

birds ability toevade predatorattacks. There-fore, birdsshould increaseenergy stores ifpossible when-ever food is like-ly to becomeless availableand reduceenergy stores asforaging condi-tions improve.

Other investigators have provided evi-dence that some shorebird species suchas Black-bellied Plover (Pluvialis squata-rola) and Redshank (Tringa totanus) canrecover body mass lost during periods ofnegative energy balance (Dugan, et al.1981. Ibis 123: 359-363). Similarly, Oyster-catchers (Haematopus ostralegus) forcedto forage for shorter periods of time com-pensate by increasing food intake to alevel that maintains the same mean con-

sumption over a longer period (Swennenet al. 1989. Animal Behaviour 38: 8-22). Amore effective adaptation, however,

would be the ability to increase bodymass reserves in anticipation of periodsof energy shortfall. In recent work onTomales Bay, I found evidence that Dunlinregulate body mass in response to thearrival of winter storms that can signalloss of feeding opportunities. However,shorebirds might manage their energyreserves more effectively by respondingonly to periods of actual food scarcity, asimposed by extended flooding of mud-

flats or by storm-related declines in preypopulations. How do shorebirds respond

when feeding opportunities are severelyrestricted?

Wintering shorebirds cannot saveenergy by temporarily reducing their rest-ing metabolism, as in the nightly torpor ofhummingbirds, because it would interfere

with their need to actively forage andevade predators both day and night. Toconserve or enhance energy stores, shore-birds might increase in their food intake,decrease the amount of energy spent onactivities, or reduce heat loss. Most shore-

Figure 1. Theoretical effects of body mass on mortality risk. As birds

increase body mass by storing more energy (primarily as fat), starvation

risk declines, but predation risk increases if birds become overweight

(bold line). Optimum body mass occurs when mortality risk is minimized,

at intermediate levels of energy storage. If feeding conditions deteriorate

(thin line), optimum body mass increases (shifts right); if predation pres-

sure increases (dashed line), optimum body mass declines (shifts left).

Proportiona

lchange

inbodymass

Test day

Figure 2. Daily body mass change in food-restricted Dunlin relative to controls pro-

vided with continuously available food (ad libitum). Boxes indicate test periods of

restricted 24 hour:24 hour (fasting:ad libitum) feeding. Treatment group was

switched between test periods. Box 1: bold line = restricted birds (n=7); thin line =

controls (n=7). Box 2: bold line = controls; thin line = restricted. All birds were pro-

vided with continuously available food outside of test periods.

Mortalityrisk

Body mass

1

0

Energy conservation in wintering Dunlin

Balancing Actsby John P. Kelly


7/16


bird species expend over half of theirdaily energy requirement just generatingenough heat to maintain internal bodyfunctions. Birds may conserve body heatby tucking bills or legs into their plumage,seeking sheltered habitats, or standing inthe lee of other individuals to avoid wind

chill. But because such thermoregulatorybehaviors are important in shorebirds atall times, there is little opportunity toincrease energy savings through addition-al behavioral thermoregulation during

winter storms. To adjust and readjusttheir energy stores to fluctuating risks ofstarvation and predation, shorebirds aremost likely to alter the amount of energyused for activities and/or the amount offood consumed.

Effects of f ood scarcity

Shorebirds in coastal habitats normal-

ly depend on feeding areas that aresuitable only during intermittent lowtides. Available foraging time is furtherreduced when winter storms, flooding, orsedimentation prevent successful foragingor access to feeding areas. By observingthe responses of aviary Dunlin to periodicfeeding constraints such as those imposedby winter storms, I tested the predictionthat Dunlin regulate body mass byincreasing energy stores when availablefeeding time is reduced and decreasingenergy stores when feeding time isextended (Figure 2). I used fixed schedules

of fasting and unrestricted (ad libitum)feeding to simulate food restriction expe-rienced by wintering shorebirds duringunusually high tides or heavy storms. TheDunlin were captured on Tomales Bay andheld temporarily in aviaries at ACRsCypress Grove Research Center. They wereprovided with freely available food (troutchow) and water. Except during periods ofenforced fasting, they maintained body

weights that were slightly greater thanweights maintained in the field. The aviarybirds never experienced even the earlystages of starvation, because fat reserves

were never depleted. The birds werereleased after measurements were com-pleted, prior to spring migration.

When aviary birds were allowed tofeed only on alternate days, they signifi-cantly increased their body mass relativeto controls (Figure 2). Increases in mini-mum body mass on successive fastingdays indicated that true fatteningoccurred in spite of temporary periods of

weight loss. When daily feeding wasrestored, body mass in food-restrictedindividuals continued to increase for twoor three days, then declined toward con-

trol levels. So whenfaced with possiblefood shortage, birdsgained weight.

In additional tests,more severely restrict-ed birds increased their

energy stores at evengreater rates. This sug-gests, not surprisingly,that birds perceive agreater risk of starva-tion under greater foodrestriction, such asmight occur duringmore severe winterstorms. Differences inregulated levels ofreserve energy furtherindicated that individ-ual birds differ in their

perceptions of optimalbody mass (Figure 1)a dimension of variation upon whichnatural selection might act.

Dunlin under a restricted feedingregime consumed more food than birdsallowed to feed continuously, but theadditional amount of energy consumed

was insufficient to account for theirincreased body mass. Increased energystorage was therefore partly achieved byreducing activity costs.

Because energy intake and use mustbalance, I was able to estimate the energy

birds used for activities by deduction,from measurements of food intake, ther-mal and resting metabolism, and energyretained or lost in stored body tissues. Iused taxidermic Dunlin mounts with hol-low copper bodies as thermometers tomeasure the temperatures (adjusted for

wind speed and solar radiation) that birdswould experience if they produced nometabolic heat, and from these I calculat-ed the amount of energy birds need tostay warm.

The results suggested that, when feed-ing opportunities are restricted, Dunlin try

to increase food intake and energy stores(Figure 2) and also become less active(Figure 3). When feeding is not possible,however, they become more active thanbirds accustomed to more suitable feed-ing conditions (see Figure 3 at Gross ener-gy intake=0). This enhanced activity isconsistent with regional midwinter flightsto new wintering areas during periods ofheavy rainfall, as well as with broader useof local foraging alternatives during winterstorms (See The Ardeid, Spring 1999). Incontrast, birds accustomed to unrestrictedfeeding opportunities may choose to ride

out an unusual winter storm by reducingactivity costs while fasting until normalconditions return (see Figure 3 at Grossenergy intake=0).

Birds are known to respond to a widerange of environmental stressors byincreasing plasma levels of corticosterone,an adrenal hormone involved in emer-gency use of energy stores as well as in

winter fattening. The secretion of stresshormones can be stimulated by inclement

weather or disruption of normal feeding

patterns. This raises an interesting possi-bilitythat endocrine-mediated respons-es to changing energy stores, weather, andforaging conditions might enable shore-birds to maintain appropriate amounts ofstored energy or might stimulate move-ments of shorebirds to alternative feedingareas. However, the relative importance ofphysiological cues is not clear.

More work is necessary to determinethe extent to which these patterns occurin free-living shorebirds. The relationshipbetween the regulation of energy storesand activity levels may be crucial in

understanding midwinter shorebirdmovements and the thresholds of shore-bird use in estuaries like Tomales Bay. s

Figure 3. Food-restricted Dunlin reduced their activity and increased their

energy intake when allowed to feed, relative to controls, but increased

their activity when forced to fast (at Gross energy intake=0). Solid circles

= ad libitum fed birds; open circles = 24 hr:24 hr (fasting:ad libitum)

restricted birds; open triangles = 24 hr:6 hr:12 hr:6 hr (fasting:ad

libitum:fasting:ad libitum) restricted birds.

Activitycosts

(kJgday)-1)

Gross energy intake (kJ (g day)-1)


8/16

have moved andreworked sedi-ment in themarsh and filledthe large scourhole in the tidalinlet. Fourdefining charac-teristics of thetidal marsh atCGP have beenanalyzed fromsequential topo-graphic surveys:tidal inlet area,tidal channellength, tidalchannel vol-ume, and tidalprism volume(Table 1).

To documentseasonal changesin the cross-sectional area ofthe tidal inlet, Iconduct month-

ly measurements from the bridge duringthe ebb flow of a median tide. A carpen-ters laser level and a bicycle reflectormounted at the north and south ends ofthe bridge provide a standard horizontalreference for measuring channel depth

with a telescoping measuring rod. As ofFebruary 2001 the area of the tidal inlet is80 ft2, which represents a 72% decrease inarea since May 1998 (Table 1). To evaluate


Since the dramatic breach of the oldNorth Pacific Coast Railroad levee atCypress Grove Preserve (CGP) in

1998, a research project has been underway to study the transformation ofLivermore Marsh. With financial assis-tance from the Marin CommunityFoundation, Audubon Canyon Ranchdeveloped a five-year research project tomonitor several physical and biologicalparameters associated with the reintro-duction of tidal circulation into theperched freshwater marsh.

The primary objectives of this studyare to document the rate and timing ofgeomorphic changes during the develop-ment of this tidal marsh and to compareLivermore Marsh to mature coastal marshsystems. Four topographic surveys of themarsh and its developing features havebeen completed to date. In May 1998,Kamman Hydrology and Engineering(KHE) volunteered to survey the 86-footlevee breach and the new tidal channel.Pacific Land Surveys (PLS) delineated thegeneral topography and physical featuresof the marsh plain in May 1999. The PLS

survey includes more than 5,000 point

elevations along ten north-south transectsthat are used to identify one-foot con-tours. Additional points indicate the loca-tion and shape of the primary tide chan-nels, some of the secondary channels, andmajor stands of marsh and riparian vege-tation. The points were reported in threestandardized coordinate systems(NAVD88; NOS and NGVD29) that allowus to compare the changing topographyof LivermoreMarsh with othercoastal marsh

systems. The PLSsurvey alsoestablished con-trol points forfuture surveys, todocument theevolution of thetidal marsh.

The area ofthe tidal inlet hasgradually de-creased since1998. Subse-quent tides and

winter runoff

Monitoring the return of tidal influence on a coastal wetland

Marsh Revivalby Katie Etienne

Tidal influence

Freshwater inflow

Tidal prism in March 2001(below 3' NGVD)

Evolving tidal channel

Perched ponds

Contour line (1.5 ft interval)

Approx. Scale

Tomales Bay

Livermore M arsh

Frank A. Campini

Bridge

Trail to

upper

freshwater

marsh

N

Figure 1. Features of evolving tidal marsh at Audubon Canyon RanchCypress Grove Preserve.

Table 1. Geomorphic characteristics of Livermore Marsh at Cypress Grove Preserve.

100 ft0

SurveyDate

May1998

Nov.1999

283

176

230

470

0.321 1.4

1.6

2.0

0.39

0.4858080Mar.2001

Tidal InletArea below3 ft NGVD

(sq. ft.)

TideChannelLength

estimated(ft.)

TideChannelVolume

below 1.5ft. (acre-ft.)

Tidal PrismVolume

below 3 ftNGVD

(acre-ft.)

1Tide channel volume in 1998 was probably slightly larger than could be determined during

this preliminary survey.

GRAPHICBYLAUREN

HAMMACK


9/16


the effect of extreme tides on channelinlet geometry, I also measure the inletduring extreme tidal events (spring andneap tidal cycles). These measurementsare conducted three times during each

year: before the rainy season begins, dur-ing the winter after eight inches of cumu-lative rainfall, and at the end of the rainyseason. So far, extreme tides have not hada significant influence on inlet geometry.

While the length of the primary tidechannel continues to increase in Liver-more Marsh, the tide channel volume hasnot increased at a comparable rate,because the tide channels are becomingshallower. Tidal prism volume hasincreased by 0.6 acre-ft since 1998. Thisvalue reflects the increased volume of theprimary channel and the capture of apond that was previously isolated fromthe channel. The geomorphic characteris-tics of the tidal marsh at Cypress Groveare controlled by the sediment supply inthe marsh, by runoff and sediment inflowfrom the watershed, and by the exchangeof tidal flow within the tidal prism (seesidebar). As the system develops weexpect to see: (1) continued infilling of thetidal inlet; (2) yearly growth of the tidalchannel in both length and width; and (3)increased tidal prism volume. However,exactly when Livermore Marsh will reachdynamic equilibrium, and what the rangeof values for each of these marsh features

will be, depends on the unique combina-tion of physical and biotic factors operat-ing within the marsh. Two possible per-turbations of the system that we cannot

predict, earthquakes and changes in sea

level, could dramatically alter theshape and volume of tide channelsand the tidal prism.

Understanding the relationshipbetween tidal prism and inlet geom-etry is an important tool for engi-neers and restoration biologists

planning to breach man-made ornatural obstructions to tidal circula-tion and freshwater runoff. To pre-dict the future topography ofLivermore Marsh, we surveyed thetide channel inlets and marsh plainelevations at older levee marshes onTomales Bay. We compared thesedata with results from eight SanFrancisco Bay marshes in Napa andSonoma counties (Coates et al.1995. Philip Williams Assoc. ReportNo. 934) to predict relationshipsbetween cross-sectional area of tidal

inlets and tidal prism.Although the inlet area of Liver-

more Marsh was larger in 1999 thanpredicted, by February 2001 it was

80 ft2significantly smaller than the 112ft2 predicted from regressions based ontidal marshes in San Francisco Bay(Coates et al. 1995). There were alsomajor differences between the size of thetidal inlets at reference marshes inTomales Bay and predicted values fromthe regressions for eight San FranciscoBay marshes. These differences appear tobe most pronounced for the Tomales Bay

marshes with the smallest watersheds.For example, at a small marsh adjacent to

Walker Creek delta (watershed 1.24 km2),the inlet area is 20% of the size predictedfrom Coates et al. (1995). The inlet of aslightly larger marsh located north ofBivalve (watershed 2.41 km2) is 23% of

the predicted size. Comparison of themarsh at Millerton Gulch (watershed 9.63km2) reveals an inlet area that is 51% ofthe predicted size.

Discharge incorporates the effect ofwatershed size, slope, permeability andlocal precipitation patterns. I compared

discharge data for the Tomales Bay refer-ence marshes with the tidal inlet area(calculated below 3 ft NGVD; Figure 2).

Although this regression should be inter-preted cautiously, because it is based ononly four marshes, the data suggest thatthe inlet area increases 78 ft2 for each 100ft3 per second of discharge (Figure 2; R2=0.98; P


10/16


Recent local increases in the abun-dances of Common Ravens (Corvuscorax) and American Crows

(Corvus brachyrhynchos) have caught theattention of birders in many parts of theSan Francisco Bay area. Occasionally,general impressions of corvid populationgrowth and fears of increasing nest preda-tion on other native species have temptedHitchcock-like fears about the future sta-tus and ecological roles of these species.

Of particular concern to AudubonCanyon Ranch is whether increases in thenumbers of ravens and crows might sig-nal severe increases in nest predation ordisturbance of colonially nesting water-birds such as herons and egrets. Inresponse to these concerns, we began astudy of local raven populations. Thestudy involves radio telemetry to track themovements of nesting ravens in MarinCounty and substantial efforts to observenest predatory behaviors of CommonRavens at heronries. As part of this study,

we conducted a series of road surveys todetermine the status of ravens and crows

in our region (Figure 1).From March through June 1999, werecorded the occurrences of CommonRavens and American Crows on 18 surveyroutes, averaging 49 km in length, estab-lished along roads. Routes were selectedto represent open/rural or urban/subur-ban habitat, and interior, outer coast, orSan Francisco Bay shore locationsthroughout the region, maximizing thedistances among routes. To keep survey

speed down, weavoided free-

ways and majorhighways.

Forty quali-fied volunteerobservers con-ducted mid-morning roadsurveys twicemonthly alongeach route.Survey teamsconsisting ofone driver andone observertraveled atspeeds of 3545mph. For eachCommonRaven or

American Crowobserved, werecorded thelocation (dis-tance) alongsurvey route,the perpendi-cular distanceand directionfrom road,species name,group size,flight direction,and behavior(flying, perch-ing, walking/

standing). We used the num-ber of birds observed perkilometer of survey route to

index corvid densities. Wethen examined differencesbetween rural and urban/suburban habitats, andamong coastal, interior andbay shore locations.

On average, 89% 2.3(std. error) of ravens and 92% 1.8 of crows were observed

within 200 m of surveyroutes. Most ravens (69% 4.4) and crows (70% 7.1)

were observed within 100 mof survey roads. Ravens and

crows observed at greater

Abundance and distribution of Common Raven and American Crow in theSan Francisco Bay area

The Birdsby John P. Kelly

Figure 1. Routes used in Audubon Canyon Ranch road surveys of Common Ravens

and American Crows in the San Francisco Bay area. Labels are route identification

numbers.

Common Raven

American Crow

Urban/SuburbanRural

Birdsperkm

Figure 2. Mean number of Common Ravens and American

Crows observed per km of survey route in rural and

urban/suburban land use areas in the San Francisco Bay

area. Values for American Crow exclude Route 11 (see

text). Error bars = standard errors.

Figure 3. Mean number of Common Ravens and American

Crows observed per km of survey route in the San Francisco

Bay Area. Error bars = standard errors. See Figure 1 for route

locations.

Common Raven

American Crow

Survey route

Birdsperkm


11/16


distances seemed to beas conspicuous as thosecloser to the road, sug-gesting that bothspecies concentratedalong roads. Concentra-tions of corvids along

highways may reflecttheir habits of foragingon highway-generatedcarrion.

Hot spots, coldspots

Corvid numbersdiffered moregreatly among

survey routes thanamong surveys withineach route, indicatingsignificant regional

variability in abun-dances of both ravensand crows. However,differences amongcoastal, interior, andbay shore locationtypes were often nogreater than amongindividual routes, indi-cating that more localized habitat fea-tures might determine the general patternin the region. If so, corvid distributionmay reflect an underlying array of localconditions that determine suitability for

foraging or breeding. If not, these pat-terns may reveal localized opportunitiesfor further population growth. The pro-portion of crows or ravens that occurredin pairs, suggesting possible breeding sta-tus, did not differ significantly amonggeneral land use types, subregional loca-tions, or routes.

Densities of Common Ravens were sig-nificantly greater along urban/suburbansurvey routes than along rural surveyroutes (Figure 2). However, the highestnumbers of ravens occurred near dairyranches in the pastoral zone of the Point

Reyes National Seashore (Figure 3).Because ravens are widely known to spe-cialize on carcasses found on ranches,this is not surprising. The road surveysalso indicated that Common Ravensoccur in significantly greater densitiesalong the outer coast than in either theinterior of the region or along the bayshore (Figure 4). Interestingly, ravens wererelatively abundant in San Francisco.Concentrated raven use of coastal andagricultural areas is matched by theirability to also exploit the most urbanizedhabitats surrounding San Francisco Bay.

American Crows were significantlymore abundant along urban/ suburbansurvey routes than along rural surveyroutes (Figure 2), with a striking exceptionin the open agricultural area south of

Fairfield, where unusually high numbersoccurred (Route 11, Figure 3). Densities ofcrows were significantly lower along theouter coast than in other subregions. Withthe exception of Route 11, densities ofcrows did not differ between bay shoreand interior routes (Figure 4). Accordingto survey results, crows seem to thrive inurbanized habitats throughoutour region.

Consistent patterns andtrends

We are examining otherexisting data to deter-mine regional trends

in the numbers of ravens andcrows and to compare with pat-terns suggested by the road sur-vey data. The North AmericanBreeding Bird Survey (BBS) is anextensive roadside survey,based on 50 three-minute pointcounts conducted along each ofthousands of 24.5-mile routesover much of North America.Because BBS surveys date backas far as 1966, they provide a

perspective on changes in

regional abundance. The BBS is managedby the U. S. Geological Survey andCanadian Wildlife Service (see the website at www.mbr-pwrc.usgs.gov/bbs).

Numbers of ravens and crows observed

along 15 BBS routes in the San FranciscoBay area reveal distributional patternssimilar to those described by the ACR roadsurvey (Figure 5). Both survey sets indi-cate dramatic variation among routes(Table 1, Figure 3). Preliminary analysesindicate overall regional increases in bothravens and crows, but local trends vary

Continued on page 10

Table 1. Breeding Bird Survey trends and mean number of birds per survey route for Common Raven and American Crow in the

San Francisco Bay area. See Figure 5 for route locations. Significant linear trends are indicated by * P


12/16


greatly across the region, suggestingsmaller-scale effects (Table 1). We are alsoexamining long-term trends in winterabundances using Audubon ChristmasBird Count (CBC) data. Preliminary looksat several decades of CBC data reveal sig-nificant overall increases in both ravens

and crows, with the strongest increasesduring the 1980s and 1990s.

We are evaluating regional breedingdistributions by compiling breeding birdatlas (BBA) data from the San FranciscoBay area. BBAs are organized and devel-oped separately by county, and they usestandardized criteria to determine thelikelihood of breeding for each birdspecies within 5-km blocks. The com-posite atlas reflects patterns that areconsistent with BBS and ACR road sur-veys (Figure 6).

The growing numbers of ravens and

crows is certainly no surprise, especiallyfor species that benefit from agriculture,road kills, and garbage in human-alteredlandscapes. But patchy distributions andvariable rates of change across the regionsuggest that explanations for their in-creasing numbers may not be so simple,and that associated increases in nest pre-dation on other species may stronglydepend on local conditions. Informationfrom ACRs corvid road survey will help usto understand the implications of other

ACR researchon raven home ranges,foraging behaviors, and nest predation at

waterbird colonies.s

This project received financial supportfrom the Marin Community Foundationand the Marin and Sequoia chapters of theNational Audubon Society.

Figure 5. Breeding Bird Survey routes in the San Francisco Bay area. Labels are route identification

numbers. See Table 1 for details on each route.

Figure 6. Composite breeding bird atlas for

Common Raven in the San Francisco Bay

area, compiled and mapped by Katie

Etienne. Filled circles indicate likelihood of

breeding in each 5-km block: large

circle=confirmed; medium

circle=probable; small circle=possible; no

circle=no ravens observed. Field data were

collected in the years indicated under each

county name (Shuford 1993, Marin County

Breeding Bird Atlas; Burridge 1995,

Sonoma County Breeding Bird Atlas; R.

Leong and B. Grummer, unpubl. Napa

County; S. Glover, unpubl. Contra Costa

County; B. Richmond, unpubl. Alameda

County; Santa Clara Atlas Comm., unpubl.

Santa Clara County; R. Johnson, unpubl.

San Mateo County; M. Eaton, unpubl. San

Francisco County).

x Ravens and crows, continued


13/16


Fire is a topic sure to arouse passionsfrom various points of view. People

who have experienced the powerand fury of a fire personally are especiallyprone to emotional responses. In thisarticle I would like to explore the role fireplays in natural ecosystems, both in thepresence and in the absence of peopleand our myriad interventions and manip-ulations, in the hope of stimulating a dis-cussion of the various roles fire couldplay on the preserves managed by ACR.

Before people arrived in the New

World, the only ignition sources werelightning, volcanoes, rock slides, andspontaneous combustion. The predomi-nant source of ignitions was lightning. Incoastal Central California, lightning firesmay have recurred on 20- to 40-yearcycles (Biswell 1989). Lightning is rela-tively rare in Central California compared

with the Midwest or the Southeast, butlightning ignitions are recorded (Sugnet1984). In his 25 years at ACRs BolinasLagoon Preserve (BLP), Skip Schwartz hasseen one fire started by lightning. Itoccurred on the ridge south of Volunteer

Canyon in the middle of the night andwas quickly suppressed.

Fire return times of 20 to 40 years areshort enough that most plant and manyanimal species were forced to adapt tothis factor. Many of the species in ourarea exhibit multiple adaptations to thecyclically recurrent disturbance causedby fire. A classic example is the redwood.Redwoods have thick barkto protect the trunk fromfire. Additionally, the smallseeds of redwoods needflood, fire, or a landslide to

remove duff in order tosurvive their first year oflife. Fire is one of the pri-mary ingredients in red-

wood reproduction byseed. Chaparral plants arecharacterized by the needfor and the ability to sur-vive intense fires. In theabsence of fire, forest treesmay replace chaparral.Recurrent fires canexclude invading trees andrenew the chaparral.

Chaparral shrubs generally exhibit twostrategies to survive fire. They mayresprout from underground root masses,or they may respond to fire with abun-dant seed germination. The seeds ofchaparral shrubs and annuals may liedormant in the soil seed bank fordecades, awaiting the signal from a fire toinitiate growth. My personal favorite fireadaptation is that of the California newt,

which exudes a viscous liquid from skinglands (Stromberg 1997). This liquidexpands into bubbles of foam, which

insulate the delicate amphibian andallow it to walk through a line of flames!These few examples indicate the broaderpattern: that fire has been a natural com-ponent of California ecosystems for ages,and that the plants and animals livinghere have had to adapt to this intenseselective pressure.

The human component

Native Americans were probablyresident in villages in our areabeginning about 4,000 years ago

(Broughton 1994). They greatly increasedthe number of ignitions and the length of

the fire season. A study of redwood treerings on Bolinas Ridge indicates that dur-ing the last 500 years there was a firesomewhere on Bolinas Ridge every two tofive years (Finney 1990). A similar studyat Annadel State Park (Sonoma County)found a similarly short return time, andthis was attributed to native burning(Finney & Martin 1992). We have a woe-

fully inadequate understanding of thebreadth of reasons Native Americansburned vegetation. They may have beensophisticated in their understanding offire and its multiple impacts. Their moti-vations may have been multiple andcomplex (Lewis 1973). A few of the rea-sons for native burning may have been:to open the forest understory for traveland hunting; to open lanes through chap-arral (strip burning); to encourage thegrowth of plants suitable for food harvest;to protect villages from fire and/or ene-

mies; to capture animals; to encouragethe growth of plants to attract animals byproviding food; or to improve habitat toincrease the populations of favored preyspecies. Even with our limited under-standing of the world view of Native

Americans and their reasons for burning,it is clear that fire was one of the mostpowerful and favored tools available tothem for altering the landscape in whichthey lived.

During the historic Euroamericanperiod in California (1861present), therehave been four major fires in the vicinity

of BLP (Van Kirk 2001). These firesoccurred in the years 1890, 1904, 1923,and 1945. They were probably much likethe 1995 Vision Fire at Point Reyes (PointReyes National Seashore 1995), with

which many readers will be familiar. Eachfire burned between 4,000 and 20,000acres. All occurred during September orOctober, the driest time of year and thetime we are most likely to get winds out

of the desert, knownas Santa Ana Winds.Under these condi-tions, which are

referred to technicallyas fire-storm condi-tions, there is little ornothing people cando to control a fire.The Vision Fire is agood example. Itburned relativelyunimpeded until the

winds reversed andcool, moist air fromthe ocean made thefire controllable. It ishumbling, and criti-

The ecological history and role of fire in ACR management

Must We Have Fire?by Greg deNevers

Continued on page 12

Table 1. Fire frequencies for west Marin sites, calculated using mean fire intervals in years

( standard deviation) between all fire dates at each site for the period of analysis. Table

recast from Brown et al. 1999.

Period of Number Mean fire Range of

Site analysis of intervals interval intervals

Pine Gulch 1 1841-1906 8 8.12.7 4 to 12

Pine Gulch 2 1906-1945 3 13.04.6 8 to 17

Pine Gulch 3 1841-1945 11 9.53.8 4 to 17

Five Brooks 1820-1905 11 7.75.0 1 to 17

Limantour 1825-1918 11 8.55.5 3 to 18


14/16


cally important, to recognize that thereare conditions under which we cannotcontrol, stop, or direct the course of a fire.

It is important to recognize that themain problem with fires occurs whenthey meet human developments. Whenfires destroy our buildings, it is a clear

loss. When forests burn, it is generally agood thing. The negative prejudice aboutfires, based on the association with struc-tures, often obscures our ability to makethis critical distinction. The MarinJournal account of the 1890 fire wouldhave the reader believe that all of thetimber on the Wilkins and Bourneranches, which later became BLP, wasdestroyed (Van Kirk 2001). But the MarinJournal account of the 1904 fire againrefers to giant oaks and redwoods andheavy woods being destroyed (Van Kirk2001). Surely 14 years is not long enough

to regrow a destroyed forest! In theaccount of the 1890 fire, the MarinJournal reported a fierce fire is raging inBourne Canyon and we can see no way toprevent its going to his buildings. In factit did not. In 1904, a group of men rushedover from Bolinas and by their effortsalone the property was saved (that is, thehouse). In the 1923 fire Arthur Bourneshouse was ignited by flying embers, butthe fire was extinguished.

Fire suppression

Two years ago many of us watched

in awe as flames approached oneof our national icons, the nuclear

laboratories at Los Alamos, New Mexico.The Los Alamos fire was, in part, a resultof our national policy of fire suppression,the Smokey-the-Bear policy. This policyimplicitly assumes that people can per-manently exclude fire from fire-proneecosystems. Actually, the only two likelyscenarios are many small, frequent fires,or few large, infrequent fires. Completeprevention is impossible. One responsein New Mexico has been to declare astate of fire emergency and to pass a law,

which the governor has signed, thatdirects state and local authorities toenter National Forests and take whatev-er measures they deem necessary toreduce the threat of wildfire to localcommunities (New Mexico 2000). Apartfrom the federal authority/states rightsissues, the New Mexico situation illus-trates another nuance in our relationship

with fire. Many Americans, especially inthe West, want to live in fire-prone habi-tats, in flammable structures, with tinderfuels surrounding our buildings. This isan esthetically pleasing approach, until

the day of the fire. Private property own-ers may be insensitive to admonitionsregarding the wisdom of this approach.

Although California State law requiresthe removal of flammable vegetationaround structures (Public Resource Code4291), compliance with this measure is

uneven and enforcement scant. Oneundesirable consequence of this situa-tion is that public land managers maycut forest or chaparral on public lands tocreate fuel breaks to protect adjacentprivate property from fire.

A Forest Service study after the LosAlamos fire demonstrated that the fireburned most intensely in and aroundhuman communities, not in the sur-rounding National Forest (ForestMagazine 2000). Fuel loading is often nothighest in the forest but rather in towns,

where horticultural plantings magnify the

fuel load. In any case, a forest with low orhigh fuel loads would carry a fire to town.

Yet the New Mexico Legislature looks tosurrounding public lands for protectionfrom fire. The policy of creating fuelbreaks on public lands to protect neigh-boring private lands is followed by theMarin Municipal Water District and theMarin County Open Space District(Charles 1993). The fuel break onPanoramic Highway near the MountainHome Inn (above BLP) provides a clearexample. Here a 200-foot wide fuel breakhas been created by removing all woody

vegetation on public land, in the hope ofpreventing a fire in the Redwood Creekdrainage from reaching private homesalong Panoramic Highway. The practicali-ty of creating fuel breaks is currentlybeing questioned. The eight-lane, asphaltfuel break in Oakland that we callHighway 24 was jumped by fire brandsmultiple times during the 1989 OaklandHills fire. The growing conventional wis-dom seems to be that protecting struc-tures through fire-safe construction (non-flammable roofs and siding) is moreeffective than creating fuel breaks.

The answer to the question rhetorical-ly posed in the title of this article is yes.

We must have fire in natural lands. TheACR scientific staff is currently preparinga fire management plan for all three pre-serves. The plan intends to be forwardlooking and proactive in its approach tofire management. We hope to incorporatethe use of controlled fire into the tool kit

we use to manage our preserves. We alsointend to prepare as much as possible for

wildfire events we cannot control, so thatthe preserves will not be negativelyimpacted. s

References

Biswell, H. H. 1989. Prescribed burning inCalifornia wildlands vegetation man-agement. UC Press, CA.

Broughton, J. M. 1994. Declines in mam-

malian foraging efficiency during thelate Holocene, San Francisco Bay, CA.J. Anthropological Archaeology 13:371-401.

Charles, L., and Associates. 1993. MountTamalpais Area vegetation manage-ment plan. Report on file, MMWD &MCOSD.

Finney, M. A. 1990. Fire history from thecoast redwood forests of Bolinas Ridgeand Kent Lake Basin, Marin Co., CA.Report on file, MMWD.

Finney, M. A., and R. E. Martin. 1992.

Short fire intervals recorded by red-wood at Annadel State Park. Madrono39: 251-262.

Forest Magazine. 2000. Experts say over-grown yards caused Los Alamos homesto burn. 2000: 10-11.

Lewis, H. T. 1973. Patterns of Indian burn-ing in California, ecology and ethnolo-gy. Ballena Press.

New Mexico. 2000. On-line at //legis.state.nm.us/sessions/01%20Regular/bills/senate/SB0001.pdf

Point Reyes National Seashore. 1995.Mount Vision Fire Incident burned areaemergency rehabilitation plan. Dept.Interior, NPS.

Stromberg, M. 1997. Caudata: Tarichatorosa (California newt). Response tofire. Herpetological Review 28: 82-84.

Sugnet, P. W. 1984. Fire history and post-fire stand dynamics of the Invernessbishop pine population at Point ReyesNational Seashore. M.S. Thesis. Univ.California, Berkeley.

Van Kirk, S. 2001. Historical perspective of

Bolinas Lagoon. Tetra Tech, Inc., SF, CA.


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In progress:project updates

North Bay counties heronand egret project We arecompleting the 11th year oftracking nesting activities inheron and egret coloniesacross five Bay Area counties.The data are used to examineregional patterns of reproduc-tive performance, disturbance,habitat use, and spatial relation-ships among heronries.

Cape ivy control LenBlumin continues to removenonnative cape ivy from theriparian vegetation in ACRsVolunteer Canyon. The use ofgoats to consume the invasiveweed was unsuccessful in

clearing out small stems andsprouts in the leaf litter. How-ever, hand weeding has beenvery successful. With most ofthe work completed along thecreek above the buildings, Lenand others are now focused onrestoring the alder grove at thebottom of the Canyon. Contin-ued vigilance in weeded areashas been important, to combatresprouts of black nightshade,Vinca, and Japanese hedgeparsely.

Common Raven study

ACR biologists, along with col-leagues at the Point ReyesBird Observatory, are radio-tracking nesting ravens inMarin County and observingraven predatory behaviors atheron and egret nestingcolonies. We also attempted toestablish conditioned tasteaversion at ACRs PicherCanyon heronry, to reduceraven predation on egretnestlings, but it is to soon toknow if the behaviors of theresident ravens have been

altered. ACRs regional roadsurvey in the San FranciscoBay area revealed concentra-tions of ravens in someurban/suburban areas andalong the outer coast.

Livermore Marsh AsACRs Livermore Marsh trans-forms from a freshwater sys-tem into a tidal salt marsh,Katie Etienne, Rachel Kamman,and Lauren Hammack arestudying the relationshipbetween increasing tidal prismand marsh channel topography.Ellen Blustein is monitoringchanges in bird use. Thesedata will be combined withmeasurements of vegetationchange to reveal fundamentalpatterns that characterizedeveloping tidal marshes, andwill contribute to futurerestoration designs.

Newt population study Thirteen years of newt surveyshave been conducted alongthe Stuart Creek trail at ACRsBouverie Preserve. The resultstrack annual and intraseasonalabundance and size/age andspatial distributions along thecreek. Last year, 61 days ofobservation yielded a count of2,246 newts, of which 96%were red-bellied newts and4% were California or rough-skinned newts.

Vernal swales Rebecca

Anderson-Jones is developingan ecological inventory andassessment of vernal swales inthe seasonal wetlands of thelower grassland at BouveriePreserve.

Shorebirds ACR fieldobservers completed the 12thyear of shorebird censuses onTomales Bay. Six baywidecounts are conducted annually.Based on these data, JohnKelly is investigating local habi-tat values and winter popula-tion patterns of shorebirds. Heis also studying the effects ofwinter storms on energy bal-ance and habitat use byDunlins.

Tomales Bay plant speciesdatabase Grant Fletcher istracking populations ofCastilleja ambiguassp. hum-boldtiensisand Cordylanthusmaritimusssp. palustris, raresalt marsh annuals at TomalesBay and in Mendocino County.

Tomales Bay waterbirds Since 1989-90, teams of fieldobservers have conducted win-ter w aterbird censuses fromsurvey boats on Tomales Bay.The results provide informationon habitat values and conserva-tion needs of 51 species, total-ing up to 25,000 birds.

Sudden oak death Rebecca Anderson-Jones istracking the threat of the fungal pathogen Phytoph-thera(a watermold, Oomycota)associated with Sudden OakDeath (SOD), which may occurat Bouverie Preserve. SOD cankill coast live oaks, black oaks,and tan oaks. We expect to beincluded in a regional mappingproject by investigators atSonoma State University andU.C. Berkeley, which will usehigh-resolution aerial photo-graphy and ground truthing to

track the progress of SOD.

Visiting investigators atACR

Yvonne Chan and Peter Arcese(Univ. Wisconsin), Subspecif-ic differentiation and geneticpopulation structure of songsparrows in the San Francis-co Bay area.

Jeff Corbin and Carla DAnto-nio (UC Berkeley), Effects ofinvasive species on nitrogenretention in coastal prairie.

Christopher DiVittorio (UCBerkeley), Dispersal and dis-turbance colonization in aCalifornia coastal grassland.

Peggy Fong (UCLA), Algal indi-cators of nutrient enrichmentin estuaries.

Brenda Grewell (UC Davis),Species diversity, rare plantpersistence, and parasitismin mid-Pacific Coast saltmarshes.

Jodi Hilty (UC Berkeley), Carni-vore use of riparian corridorsin vineyards.

Martha Hoopes and CherylBriggs (UC Davis), Effects ofdispersal on insect popula-tion dynamics and parasitoiddiversity in galls ofRhopalomyia californica on

Baccharis pilularis.Gretchen LeBuhn (CSU San

Francisco), The effect oflandscape changes on nativebee fauna and pollination ofnative plants in Napa andSonoma counties

Jacqueline Levy (CSU SanFrancisco), The impact ofbutterfly gardens on pipevineswallowtail populations.

Steven Morgan, Susan Ander-son, and others (UC BodegaMarine Lab), Western Center

for Estuarine Ecosystem Indi-cator Research (ecologicalindicators in West Coastestuaries).

Jennifer Shulzitski (USGS Gold-en Gate Field Station), Multi-scaled vegetation data topredict wildlife species distri-butions using a Wildlife Habi-tat Relationship model.

Bibit Traut (UC Davis), Struc-ture and function of coastalhigh salt marsh ecotone. s



16/16

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

any member of the family

Ardeidae, which includes herons,

egrets, and bitterns.

The Ardeid is published twice yearly 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. 2001 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 PRESERVE 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 CenterP.O. Box 808Marshall,CA 94940

(415) 663-8203

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Permit No. 2

Stinson Beach, CA

Verna l pool at B ouverie Preser ve see page 1

Documents

The Ardeid Newsletter, 2001 ~ Audubon Canyon Ranch