The Ardeid Newsletter, 2009 ~ Audubon Canyon Ranch

8/9/2019 The Ardeid Newsletter, 2009 ~ Audubon Canyon Ranch

1/16

Conservation Science and

Habitat Protection at

Audubon Canyon Ranch

2009

Bouverie Preserve

wetlands dynamics

parental wisdom

nesting Great Egrets

Bolinas Lagoon

heron and egret surveys

growing diversity

seed collection for

ecological restoration

THE

Ardeid


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the Ardeid 2009

In this issue

Fountain of Fountains: Exploring the dynamics o seasonal wetlands at the Bouverie Preserve by Sherry Adams and Arthur Dawson page 1The Ecology of Parental Wisdom: Strategic nest attendance by Great Egrets by John P. Kelly page 4Local Values: A ne scale census o herons and egrets on Bolinas Lagoon by Emiko Condeso page 7Growing Diversity: How seed collection infuences genetic diversity in ecological restoration by Hillary Sardias page 9

Cover:A Snowy Egret oot stirring to fnd prey. The number o oraging Snowies in Bolinas Lagoon increases during all

and winter. Photo by Philip Loring Greene.

Ardeid masthead Great Blue Heron ink wash painting by Claudia Chapline.

Audubon Canyon Ranch Staf

AdministrationSkip Schwartz, Executive DirectorJohn Petersen,Associate DirectorStephen Pozsgai, ControllerYvonne Pierce,Administrative Director and

Bolinas Lagoon Preserve ManagerBonnie Warren,Administrative Manager, Cypress Grove

Research CenterNancy rbovich,Administrative Manager, Bouverie

PreserveSuzanna Naramore,Administrative Assistant, Bolinas

Lagoon PreserveLeslie Sproul, Receptionist/Oce Assistant, Bolinas Lagoon

Preserve

Development

Didi Wilson, Director o Development andCommunications

Cassie Gruenstein, Director o Major GifsJennier Newman, Development ManagerBritt Henke, Development AssistantPaula Maxeld, Publicist

Science and EducationJohn Kelly, PhD, Director o Conservation Science and

Habitat ProtectionDaniel Gluesenkamp, PhD, Director o Habitat Protection

and Restoration (HPR)Sherry Adams, Biologist, Modini Ingalls Ecological PreserveEmiko Condeso, Biologist/GIS Specialist, Cypress Grove

Research CenterGwen Heistand, Co-director o Education and Resident

Biologist, Bolinas Lagoon PreserveJeanne Wirka, Co-director o Education and Resident

Biologist, Bouverie PreserveBob Baez, Helen Pratt Field Biologist

Hillary Sardias, HPR Projects Leader, MarinCassandra Lui, HPR Field echnicianClaire Seda, Weekend Program Facilitator, Bolinas Lagoon

Preserve

Land Stewards

Bill Arthur, Bolinas Lagoon PreserveDavid Greene, Cypress Grove ResearchCenterJohn Martin, Bouverie PreserveMatej Seda,Maintenance Assistant, Bolinas Lagoon

Preserve

Research AssociatesJules EvensHelen PrattRich Stallcup

The Watch

Jared Abranson (N), Nancy Abreu (H), KenAckerman (B,P), Julie Allecta (P), Jason Allen(C,N), Sarah Allen (S,W), Janica Anderson(H), Jennie Anderson (H), Norah Bain (H,S),Brian Bartsch (F), Katy Baty (W), om Baty(W), Cheryl Belitsky (H), David Belitsky(H), Jennier Benham (F), Phyllis Benham(W), Shelly Benson (W), Evelyn Berger (P),Louise Bielelt (B,P), Louise Bielelt (N),Sherm Bielelt (B,P), Gay Bishop (S), StephanieBishop (H), Anna Bjorquist (N), GiselleBlock (H), Eileen Blossman (F), Len Blumin(F,H,S,W), Patti Blumin (H), Ellen Blustein(H,S), Janet Bosshard (H), Bruce Bowser (F),Connie Bradley (F), Anna Marie Bratton(F), Melissa Brockman (H), Susan Bundschu(P), Phil Burton (H), Denise Cadman (H),Miriam Campos (F), Barbara Carlson (P),om Cashman (H), Ann Cassidy (H), RobinChase (N), Mae Chen (F), Dave Chenoweth(F), David Ciardello (N), Careana Clay (F),Brian Cluer (H, pilot), George Clyde (H,W),Mary Ann Cobb (F), Hugo Condeso (H,W),Judith Corning (W), Patricia Craves (F),Sylvia Craword (P), Brian Cully (F), SharonDankworth (C,N), Karen Davis (H), MelissaDavis (H), Jaime Della Santina (F), JohnDineen (H), Caroline Dutton (H), Bob Dyer(H), Joe Eaton (F), Dexter Eichhorst (F), ZachEnglish (F), Rick Ernst (H), Jules Evens (S,W),Mark Fenn (H), Binny Fischer (H,W), LeslieFlint (W), Jobina Forder (B,P), Kevin Fritsche(H), Dennis Fujita (B,P), Jennier Garrison(H), Daniel George (S,W), Rebecca Geronimo(P), James Gibbs (F), Marjorie Gibbs (F),Anthony Gilbert (H,S), Beryl Glitz (H), DohnGlitz (H), Pedro Gomez (N), Johann Grayson

(N), Philip Greene (H), Marty Grin (W),Daniel Grubb (N,P), Sophia Grubb (C,N,P),Brian Gully (V), Alyssa Hall (P), Karlene Hall(P), Madelon Halpern (H), Lauren Hammack(H), Fred Hanson (S), Roger Harshaw (S,W),Alison Hastings-Pimental (P), Will Haymaker(P), Guy Henderson (F), Andrea Hernandez(C), Earl Herr (B), Diane Hichwa (H), VickyHill (P), Maddy Hobart (N), Joan Homan(H), Ingrid Hogle (P), Ken Horner (F), RogerHothem (H), Lisa Hug (H,S), Merle Hunter(F), Ellie Insley (V), Scott Jarvis (P), VictoriaJarvis (P), Bobbie Jenkins (N), aylor Jensen(N), Rick Johnson (H), Linda Judd (N),Gail Kabat (W), Guy Kay (H), Audrey King(H), Doug King (H), Emma King (P), AndyKleinhesselink (F), Ellen Krebs (H), CarolKuelper (F,S), Dawna La Brucherie (P), JoanLamphier (H,S,W), Brett Lane (H), FriedaLarson (N), Dakota Lawhorn (N), Scott

Lawyer (C), Galen Leeds (S), Lamar Leland

(F), Stephanie Lennox (H), Robin Leong(H), Eileen Libby (H), Joan Lippman (H),Marcus Lipton (P), Wayne Little (H), BertLombino (P), Carolyn Longstreth (H,S,W),John Longstreth (H,S,W), Anthony Lucchesi(N), David Mac Hamer (H), Pat Macias(H), Lyn Magill (B), Charlotte Martin (P),Richard Martini (F), Pat McCarey (P), JudyMcCarthy (W), Mark McCaustland (H,W),Dave McConnell (H), Matthew McCrum (F),Alexandra McDonald (S), Diane Merrill (H),Jean Miller (H), Sarah Minnick (P,W), JimMoir (C), Corinne Monohan (P), StephenMoore (H), Ian Morrison (W), Dan Murphy(S), Joan Murphy (S), Kim Neal (H), DexterNelson (N), Len Nelson (H), Wally Neville(H), erry Nordbye (S,W), Grace Noyes (P),Pat OBrien (N,P), Shiela ODonnell (H),ony Paz (F), Emily Pellish (P), BrittanyPenoli (P), Genevieve Perdue (P), Louis Petak(W), Kate Peterlein (S), Emma Pierson (N),Alison Pimentel (P), Sally Pola (P), LaurenPopenoe (N), Grace Pratt (H), Peter Pyle (S),Lara Rachowicz (H), Je Reichel (H), LindaReichel (H), Don Reinberg (S), Margot Reisner(F), Arlene Reiss (F), Maria Rivera (H), WillRobinson (F), Jordon Rosado (N), GlendaRoss (B), Christine Rothenbach (H,P,S), EllenSabine (H), Stacey Samuels (P), Jack Sandage(F), Marilyn Sanders (H), Diana Sanson (N,P),Sharon Savage (C), Phyllis Schmitt (C,H,N),Alice Schultz (H), Harold Schulz (H), TeresaSchulz (P), John Schwonke (B), LindseySegbers (P), Steve Shaer (H, pilot), HeatherShannon (F), Richard Shipps (P), MarjorieSiegel (H,W), Jane Sinclair (P), Paul Skaj (W),Elliot Smeds (C,N), Austin Smith (N,P), Joe

Smith (W), Joseph Smith (W), Pat Smith (H),Ben Snead (H,W), John Somers (S,W), NolleneSommer (N), Robert Speckels (H), BobSpoord (H), Sue Spoord (H), Jude Stalker(W), April Starke Slakey (P), Jean Starkweather(H), Serena Stoepler (P), Michelle Stone (C),ina Styles (H), Ron Sullivan (F), Lowell Sykes(H), Judy emko (H,S), Janet Tiessen (H),Eric Tistle (P), Gwendolyn oney (S,W),Vicki rabold (P), Mike racy (N,P), Nickracy (C,N,P), Kayla rbovich (P), Tomasucker (H), Gerrit Van Sickle (N), DianeVoorhoeve (H), Sue Walker (P), anis Walters(S), Wes Weathers (H), Grace Wellington(C), Casey Wells (P), Jim White (H,W), DaveWhitridge (F), Adele Wikner (H), Ken Wilson(W), Linda Wilson (N), David Wimpfeimer(F,H,S,W), Dylan Witwicki (C,N), Bill Wolpert(W), Carol Wood (P), Patrick Woodworth(H,S,W), Bailey Wyate (N)

Volunteers or ACR research or habitat restoration projects since Te Ardeid2008. Please call (415) 663-8203 i your name should have been included.

Project Classifcations BBouverie Stewards sCCraysh Research Project s

FFour Canyons Restoration ProjectsHHeron and Egret Project

sNNewtMonitoring sPHabitat Protection sSomales Bay Shorebird Census s

VVernal Pool Restoration sWomales Bay Waterbird Census


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Every day, 15,000 cars pass within view oan especially valuable area o habitat atACRs Bouverie Preserve in Sonoma Valley,yet the area is rarely visited, since no trailleads to it. Tis habitat uctuates wildlythrough the course o the year. During the

winter rains, plants germinate and insectsand other tiny invertebrates enter into theaquatic phase o their lives. In spring thesespots slowly dry out, wildowers bloom,grasses grow, and rogs hop o on new legs.Tis is ollowed by complete desiccation,with a handul o specially adapted plants,such as the aromatic vinegar weed (richo-stema lanceolatum), growing and oweringin the heat o summer. Tis dynamic habitatis the wetlands o Lower Field o the Bouv-erie Preserve (Figure 1).

In addition to the changes this habitatgoes through in the course o a year, it can

look quite dierent rom one year to thenext. For example, in most years the Bouv-erie wetlands are home to over 100,000 in-dividuals o the rare vernal pool wildower,dwar downingia (Downingia pusilla), but in2009, due to the unusual winter precipita-

tion pattern, only about 14,000 were present.Like other annual plants, this one has a largeseed bank and is expected to thrive againwhen the conditions are supportive. Tissort o interannual variation is expected inthe natural world.

Each time we consider changes at a di-erent temporal scale, the patterns we havepreviously ocused on may ade rom view,and new ones become apparent. I we takeone more step back, to consider changeswithin a timerame o decades to centuries,what patterns overshadow these well-knownyearly cycles and year-to-year uctuations?

We know that the wet-lands o Sonoma Valley havegone through major changesin the last 200 years. In the

very rst written descriptiono Sonoma Valley, FatherJose Altimira remarked onthe many springs, ponds,marshes, and creeks onthe valley oor. Water wasnoticeably more abundanthere than anywhere else hewent, including Petaluma,Napa, and Suisun valleys.

Altimira was so impressed bythis abundance that he nick-named Sonoma Valley unmanantial a manantiales ora ountain o ountains. Teabundance o water was oneo the reasons he chose to

establish his mission here.Te largest wetland was in the upper

part o the valley. Tough it was calledthe Kenwood Marsh, it was really a chaino marshes and wetlands covering about400 acres and stretching ve miles rom

the watershed boundary (Pythian Road),through present-day Kenwood, to nearDunbar School in Glen Ellen. In act, thismarsh complex extended all the way to theedge o modern-day Santa Rosa, suggestingthat a subsurace connection existedandmay still existbetween the Sonoma Creekand Santa Rosa Creek watersheds (Anony-mous 1837). Groundwater was exceptionallyhigh throughout this part o Sonoma Valley.Some o the Kenwood Marsh probably heldsurace water throughout the year (Boggs1861). By catching runo rom winterstorms and releasing it over many months,

Exploring the dynamics o seasonal wetlands at the Bouverie Preserve

Fountain of Fountains

by Sherry Adams and Arthur Dawson

2009 THE ARDEID page 1

Figure 1. A mang tap

ttc (m cnt gn)

ac wtlan 5A t ppa

vgtatn mntng.

Mawam (Limnanthes douglasii

p douglasii), a wtlan gnalt,

t mnant pc.

sherryAdAMs


4/16

the Kenwood Marsh acted as a sponge,reducing downstream ooding and increas-ing the ow o Sonoma Creek during thesummer dry season.

Investigating Bouverie Preservewetlands

At the Bouverie Preserve we wanted to

know more about our wetlands, includinghow they may have changed over time. Weknew there were some seasonal wetlands inthe grassland that borders the highway, butwe had no detailed inormation about thehydrology. We suspected that the wetlandswere all vernal pools in various states o deg-radation. We hypothesized that the shallow-er wetlands may once have been deeper andthen suered rom silt accumulation causedby management practices in a ormer era.

Te majority o vernal pools in Calior-nia have been destroyed (Holland 1978),and the remaining ones are home to rare

species. Because degraded vernal pools arean area o great conservation concern, wewere able to secure unding to investigatethe nature o the wetlands o the LowerField. Te investigation involved our activi-ties. First, we marked the deepest part oeach wetland and then, during the rainyseason, revisited that location each week tomeasure water depth. Second, we conductedspringtime vegetation surveys and usedgrazing, prescribed re, and mowing to con-trol introduced European grasses in the di-erent portions o the Lower Field. Tird, to

look or evidence o silt accumulation, weasked Dr. Steve alley, a soil scientist withextensive vernal pool experience, to investi-gate the wetland soil conditions. Finally, weinspected modern and historic aerial photosor evidence o wetland modication.

Hydrology

We ound two types o wetlands in theLower Field o the Bouverie Preserve. One

type quickly lls when it is raining, andthe water level drops between precipitationevents. Tis is consistent with the expla-nation that these wetlands have a mostlyimpermeable clay hardpan bottom (as with

vernal pools). Rainwater collects in themand then evaporates (Figure 2, dashed lines).

Te second type o wetland never holdsmuch water (less than 10 cm), and the waterlevel rises only slightly in response to rainevents, dropping slowly aerwards (Figure2, solid lines).

VegetationIn the rst type o wetland, the one

with a ashier hydrograph, or greater up-and-down swings in charted water level,characteristic vernal pool species werepresent. In the second type o wetland, theone with lower, more stable water levels,

characteristic vernal pool species were notound. Instead, these areas were dominatedby grasses and grass-like species (sedges andrushes). Aer mowing or grazing, we sawsome native wildowers in this second typeo wetland, but these were not vernal poolspecialists. Rather, they were wetland gen-eralists such as meadowoam (Limnanthesdouglasii ssp douglasii; Figure 1) and marshmonkeyower (Mimulus guttatus).

Wetland 9 (Figure 3) is shallow, nodeeper than our second group o wetlands,the wet meadows (Figure 2). Yet aer weused prescribed re in 2007 to minimize thegrowth o grasses in this area, the rare vernal

page 2 THE ARDEID 2009

Figure 2. Maxmm wat pt at val wtlan ng wnt, 20072008. Wtlan wt a a

ln av gat wng (a ygap) tan t wt a l ln.

Table 1. Caacttc vnal pl pc an gnalt wtlan pc t Bv Pv, an t wtlan

n wc ty a n. s Fg 3 t lcatn nmb wtlan.

Wetland2 4 9 7 1 5A

Vernal pool species

water pygmyweed (Crassula aquatica)

calicoower (Downingia concolor)

dwar downingia (Downingia pusilla) coyote thistle (Eryngium aristulatum)

quillwort (Isoetes howellii)

popcorn ower (Plagiobothrys stipitatus)

wolly marbles (Psilocarphus brevissimus)

pacic oxtail (Alopecurus saccatus)

Generalist wetland species

meadowoam (Limnanthes douglasii)

marsh monkeyower (Mimulus guttatus)

iris-leaved rush (Juncus xiphioides)


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pool specialist dwar downingia was present.We did not introduce this species, so itspresence in wetland 9 suggests that the seedbank o these wetlands is long-lived and canprovide clues to the history o these sites.

Soil investigationsWe ound no evidence that the wetlandswere once deeper and have been llingin, though it is impossible to rule this outcompletely, based on the soil investigations.In some wetland areas o the Lower Field,including wetland 1, Dr. Steve alley (2008)observed soil mottling, indicating a longhistory o wetting and drying (Figure 3).During the course o excavating soil pits, hediscovered that wetlands 7 and 5a, whichhave water levels that uctuate less than thetypical vernal pools, are ed by subsuraceseeps. He also ound no mottling in the

swale that parallels the highway, suggestingthis swale may not be natural and was cre-ated as a byproduct o highway construction(Figure 3).

Photographic investigationsModern aerial photos o the area show

swales that end abruptly at roads andproperty boundaries. Other swales dead-endaer short stretches where they run exactlyparallel to constructed eatures like the high-way and an apartment complex (Figure 3).An historic photo rom the U.S. Department

o War indicates this pattern was alreadyevident in 1942.

Putting together all the piecesWe ound no evidence to suggest that the

hydrology o the Bouverie wetlands has been

aected by silt accumulation. Te hydro-logical, biotic, and edaphic (soils) evidencerevealed two distinct types o wetlands inthe Lower Field o the Bouverie Preserve.Te wetlands with ashier hydrographs areappropriately called vernal pools because otheir characteristic vegetation and the likelypresence o a clay hardpan associated withhighly variable water depths (dashed linesin Figure 2). In our system, these vernalpools are primarily ed by overland ow orainwater. Te other type o wetland we haveis wet meadow. Teir hydrographs suggestthat our wet meadows are ed primarily by

the subsurace ow o ground water (solidlines in Figure 2).

Te basic sources o water or these twotypes o wetlands, precipitation and subsur-ace ow, have probably not changed overtime, since they are dictated by the soil andsubsurace water patterns. However, aboutve years ago the preserve had to deepenits well, so we know that there have beensignicant local changes to the groundwater level. What has happened to Altimirasountain o ountains? Agricultural andresidential development has played a large

2009 THE ARDEID page 3role in draining the land. Gutters, ditches,and hard suraces shunt winter rains quicklythrough the watershed to the bay and ocean.Flooding is reduced, but so is the ground-water that sustains our creeks and wetlands.Historical investigations suggest that since1823, Sonoma Valley has lost more than 95%o its reshwater wetland area (Dawson et al.2008).

Based on our eld observations, thepatterns evident on the aerial photograph,and documented historical trends in thewetlands o the Sonoma Creek watershed,we think that the main ways our wetlandshave changed are in the reduction o theirextent, the loss o hydrologic connectivity,and, possibly, a reduction in the number odays o inundation each year. Tey may haveonce been one small part o a large complexo wetlands in Sonoma Valley. Te Bouv-

erie Preserve provides a home or this relicthabitat and its resident species, now rare inSonoma County.

For every answer suggested by an eco-logical mystery, new questions arise. Did ourseasonally wet meadows previously remainwet or a greater part o the year? Te wetmeadows are currently dominated by intro-duced invasive species. What plant speciespreviously dominated our wet meadows,and what animal species called them home?In general, wetlands provide importantecosystem services, by ltering nutrients

and pollutants, providing ood control, andsustaining natural environmental conditionsthat humans value. What ecosystem servicesdo our wet meadows provide?

We are grateful to the US Fish and WildlifeService Private Stewardship Grant Program,Te Community Foundation of SonomaCounty, and the Rockey Family Foundationfor funding grassland restoration work at theBouverie Preserve. Conversations with soilscientist Steve alley informed this article.

Reerences cited

Anonymous. c. 1837. ereno Nombrado Guilucos Solicitadopor Juan Wilson. Bancro Library, University o Calior-nia, Berkeley. Map.

Boggs, W. 1861. Caliornia Land Court ranscript, LosGuilucos Rancho. July 31. Bancro Library, University oCaliornia, Berkeley.

Dawson, A., M. Salomon, A. Whipple, and R . Grossinger.2008. An introduction to the historical ecology o theSonoma Creek watershed. Sonoma Ecology Center.

Holland, R. F. 1978. Te geographic and edaphic distribu-tion o vernal pools in the Great Central Valley, Calior-nia. Caliornia Native Plant Society, Special Publication4:1-12.

alley, S. 2008. Bouverie soils investigation. A report toAudubon Canyon Ranch.

Figure 3. Wtlan Bv Pv Lw Fl an anng lan. Nmb ncat nval wtlan.

hgway 12 c m t pp lt t lw gt t aal pt.


6/16

Ionce watched a pair o ravens land nextto a Great Egret nest that was occupiedby two unguarded chicks. Immediately, theravens proceeded to harass the young birds.Aer dodging several bill-thrusts rom thedeensive egret chicks, one o the ravensgrabbed a nestling by its bill, pulled it down,and killed it. Although events like this seemgruesome, they are not unusual in heron-ries. Chicks guarded by adults are virtuallyimmune to attack by ravens, but, surpris-ingly, herons and egrets typically leave their

young unattendedat the nest. We arecurrently working tounderstand this para-dox, by investigating

just how Great Egrets(Ardea alba) nesting at

ACRs Bolinas LagoonPreserve schedule theirnest attendance dutiesto maximize their abil-ity to edge healthyyoung (Rothenbachand Kelly, in prepara-tion).

Midway throughthe nesting cycle,herons and egrets shirom guardian topost-guardian nestattendance behavior.

During the guardianperiod, parents shareincubation duties byalternating their timeat the nest so that,together, they attendthe nest continuously.Aer the eggs hatch,adults continue totake turns attendingthe nest and orag-ing. When one parentarrives at the nest with

ood or the nestlings,the other takes o to search or more ood.When Great Egret nestlings reach three toour weeks o age, both parents begin to or-age or ood simultaneously. Tis combinedeeding eort provides young with moreood but leaves them unguarded exceptduring brie, renzied eeding episodes. Asnestlings grow, they become more deen-sive and the likelihood o nest predationdeclines, but younger, smaller nestlings canbe easily taken by predators. Presumably,the intensied, post-guardian eeding activ-

ity gives edglings a valuable head start. Buthow much time should parents devote tonding ood vs. guarding their young?

Te care o parents or their young iscommon throughout nature, sometimesrevealing impressive or even heroic eorts.What interests ecologists is that such care

is generally adaptive and oen strategic. Inbirds, patterns o nest attendance are strong-ly inuenced by the developmental needs otheir eggs and nestlings, by the challengeso nding enough ood to support a amily,and by the complex and dynamic behaviorso nest predators. A complete commitmentto any one o these concerns, however, canresult in the neglect o other needs. So howdo egrets determine the best way to manageamily responsibilities? As in humans, thebest egret parenting is ad hoc and dependson an ability to make wise decisions inresponse to changing conditions.

How parents make decisionso examine nest attendance choices,

we addressed two hypotheses based onnumerous observations o Great Egret nestssubject to the risk o predation by residentCommon Ravens (Corvus corax). First, weconsidered the rade-o Hypothesisthategrets guard their nests continuously, toreduce predation risk, until increasing ooddemand o the developing nestlings orcesboth parents to orage or ood simultane-ously. Tis idea proposes that the increasing

risk o nestling starvation orces parents toleave their nests unguarded. o test this hy-pothesis, we evaluated how the age o chicksat the onset o the post-guardian periodaects reproductive perormance.

Under the rade-o Hypothesis, wepredicted that egrets would guard theirnests as long as possible and that ewer neststhereore would be taken by predators. Weexpected that the associated sacrice ooraging time might reduce the number ochicks produced in successul nests, becausesome o the young might starve. Among


Strategic nest attendance by Great Egrets

The Ecology of Parental Wisdom

by John P. Kelly and Christine A. Rothenbach

joANNeKAMo

Wn yng gt ac t t wk ag, pant mt wg cmpt-

ng callng gang t nt agant pat an gatng m

nng wtlan.


7/16


nests that successully avoid predation, how-ever, those with shorter guardian periodsshould be able to raise more young. We alsoexpected a narrow range o chick ages at theonset o the post-guardian period, becauseparents might guard their nests until theiryoung reach some critical age when ooddemand orces both parents to search orood. Finally, under the rade-o Hypothe-sis, we expected relatively little synchrony inthe onset o post-guardian behavior in thecolony, because nests initiated at dierenttimes should reach the critical nestling ageat dierent times.

Second, we tested the Dilution Hypoth-esisthat adult egrets in a colony synchro-nize the time o the season when they begin

to leave their nestsunguarded, to reducethe per capita risk opredation by spread-ing risk across a largerpool o vulnerablenests. Nestlings are

more likely to be takenby predators whenthey are smaller, so themost dangerous timeo the season is whenthe developing youngare rst le unat-tended. o test Dilu-tion Hypothesis, wecounted the numbero other post-guard-ian nests in the colonyon the day when each

nest was rst le unattended.Under the Dilution Hypothesis, wepredicted that, in each successul nest, morechicks would be edged: i reduced percapita risk o nest predation allows parentsto ocus more time on oraging or ood,they may be able to support larger amilies.We also expected that greater synchrony inleaving nestlings unattended might lead tomore nest ailures, because any late broods,with relatively small chicks, might be easilytaken by predators. Finally, under the Dilu-tion Hypothesis, we expected a wider rangeo chick ages at the onset o the post-guard-ian period, a necessary result o synchroniz-ing parental behavior among nests initiatedat dierent times.

Measuring parental behaviorTe nesting perormance o all breed-

ing pairs o egrets in the heronry has beenmonitored annually since 1967 (Pratt andWinkler 1985, Kelly et al 2007). For thisstudy, we used nesting data rom 19 years(1984,19871997, and 20022008), exclud-ing years when there was no observed nestpredation or when the timing o the post-guardian period was not precisely measured.

o ocus on the parents competingchallenges o nding ood or nestlingsand protecting them rom predators, weincluded nests only i they met the ollow-ing criteria: (1) at least one egg was hatched;(2) nest ailure, i it occurred, was caused bypredation; (3) the length o the guardian pe-riod was precisely determined; and (4) thenest was the rst o the season at that nestsite and likely to have been the parents rst

attempt that season (initiated beore colonysize began to decline). I an entire brood dis-appeared between observations, we assumedthat it was taken by a predator.

o account or dierences in parentalbehavior between successul and unsuc-cessul nests, and among successul neststhat edged one, two, or three young,we compared several statistical models(explanations o egret behavior) based onobservations o nesting egrets. Te modelsincluded controls to account or annualdierences in colony productivity, intra-seasonal timing, and environmental actorssuch as rainall or temperature. Te analysisalso distinguished egret parental behaviorbetween years with and without resident

Figure 2. Gat egt pant wt ccl nt (nt takn by pat) a

lkly t g m yng ty c t lngt t nt gaan p.

Figure 1. Avag pcnt Gat egt nt tat cap patn n latn

t t lngt t nt gaan p (ay at t atc).

PhiLiPLoriNGGreeNe

A ntng gt gw lag, bt pant wk t mt t nca -

man, tnng t t nt nly nz ng vt.


8/16


ravens. We then examined the extent towhich the consequences o parental behav-ior explained by the models were consistentwith the predicted outcomes o the Dilutionand rade-o hypotheses.

Patterns o parental careOur results were consistent with the

predictions o the rade-o Hypothesis.When egrets guarded their nests or a longerperiod o time, they decreased the chanceo nest predation (Figure 1). However,parents that successully avoided nestpredation were likely to edge more youngi they reduced the length o the guardianperiod (Figure 2)presumably because oincreased time or oraging. We also oundsupport or the Dilution Hypothesis. GreatEgrets edged more young, on average, ithey began the post-guardian period whenmore unattended (post-guardian) nests werepresent in the colony (Figure 3).

Egrets that made complex decisions tooptimize trade-os in reproductive peror-mance related to the combined risks o nestpredation and nestling starvationdecisionsinuenced by the age o nestlings, energydemand, ood supply, oraging opportuni-ties, and predation pressureachieved thehighest reproductive success (Figure 4).How sensitive are nesting egrets to changesin predation risk and opportunities ororaging? Simulations based on our resultssuggested that egrets are likely respondto increases in the presence o ravens by

extending the length o the guardian period,which reduces available oraging time(Figure 4). Under simulated decreases inthe presence o ravens, egrets reduced thelength o the guardian period, increasingoraging time.

Conservation trade-ofs

Successul parenting involves complexchoices based on continual assessmentso multiple concerns. Te most successulGreat Egret parents balance the costs andbenets o guarding the nest continuously,leaving to gather ood or their young, andaligning the peak period o nest vulner-ability with other nests in the colony. Tesecosts and benets have potentially impor-tant implications or conservation.

Based on our results, restoring thequality or quantity o surrounding wetlandeeding areas might not only allow nestingegrets to reduce their oraging range, spendless time oraging, or increase the amounto ood they bring back to their youngitmay also allow parents to increase thelength o the nest guardian period. Tis, inturn, might allow them to compensate orincreases in predation pressure related tointroduced nest predators or human subsi-dies o ravens or other predators. Similarly,reducing the threats o introduced or subsi-dized nest predators in heronries might al-low egret parents to reduce the length o thenest guardian period, increasing the amounto time they can spend gathering ood or

their young. Tis, in turn, would reduce therisk o nestling starvation and help parentscompensate or reduced wetland quality orquantity, including wetland losses related toclimate-induced sea level rise.

I conservation eorts can protect orimprove heron and egret oraging oppor-tunities in surrounding wetlands and can

limit or reduce threats caused by introducedor subsidized nest predators, then heronsand egrets might be able to sustain eec-tive levels o reproduction through adaptiveparentingin spite o dramatic changes tothe environment. Alternatively, the expectedresult o spiraling demands on egret parentsis declining colony size or abandonment othe colony site. As in other areas o conser-

vation, the ecological implications o nestingbehavior suggest benets and concerns orthe protection o heronries.

Reerences cited

Kelly, J. P., K. Etienne, C. Strong, M. McCaustland, and M.L. Parkes. 2007. Status, trends, and implications or theconservation o heron and egret nesting colonies in theSan Francisco Bay area. Waterbirds 30: 455-478.

Pratt, H. M., and D. W. Winkler. 1985. Clutch size, timing olaying, and reproductive success in a colony o Great BlueHerons and Great Egrets. Auk 102: 49-63.

Figure 4. Pct nmb Gat egt g p nt attmpt at Blna

Lagn, pltt agant t lngt t nt gaan p (at avag

val t vaabl). da ln = avn pnt; tt ln = avn ab-

nt; l ln = 50% canc avn pnc. Vtcal nc ln ncat

t pct lngt t gaan p.

Figure 3. Gat egt g m yng, n avag, pant bgn t pt-

gaan p nt attnanc at a tm wn m nt n t clny a

nattn.


9/16

In the aernoon light, the expanse oBolinas Lagoon is a mirror whose suraceis broken by exposed mudats and ras ooating waterbirds. Te water ranges romshallow, to deep and salty, to brackish, pro-

viding a wide variety o habitats or wildlie.More oen than not, herons and egrets canbe seen in the shallows, oraging singly or in

groups. During the breeding season, one othe largest and longest-lived heron and egretnest sites in the Bay Area can be ound onthe northeast shore o the lagoon at PicherCanyon, Audubon Canyon Ranch (Figure 1).

For more than 40 years, researchers atACR have monitored the Picher Canyonheronry, using a meticulous, twice-weeklyeld protocol to obtain measures o colonysize and reproductive success. Tese andother data have contributed to the recog-nition o Bolinas Lagoon as a wetland ointernational importance by the RamsarConvention (see Ardeid 2006). Although

the heronry is intensively studied, we haveonly just begun to examine how these birdsutilize the lagoon itsel. Because nesting her-ons and egrets tend to restrict their oragingto wetlands close to their nest sites (Kellyet al. 2008), Bolinas Lagoon is more thansimply a beautiul sightit is critical habitatupon which the reproductive success o the

heronry depends.Understanding the patterns o wadingbird use o the Bolinas Lagoon will greatlyenhance our ability to address local manage-ment concerns and also help to develop amore general understanding o how heronsand egrets use the wetland landscape. Previ-ous work by PRBO Conservation Scienceshows that numbers o herons and egretson the lagoon have uctuated over time(Shuord et al 1989). However, we do notyet understand the extent to which heronand egret abundance and distribution inthe lagoon varies in relation to ne-scale

characteristics o habitat. o address thisquestion, and to augment a separate investi-gation o heron and egret oraging behavior,researchers at ACR conducted standardizedcensuses o Great Egrets, Great Blue Herons,and Snowy Egrets on the lagoon. Fromspecied locations along the shore, theyused binoculars and telescopes to identiy

the species and locations o all wading birdson the lagoon. Each one-hour census tookplace on a medium tide (2.53.5 abovemean lower low water). We noted whetherobserved birds were solitary or in groups,whether they were in a oraging or non-oraging posture, what type o habitat theywere in (emergent vegetation, upland, mud-at, etc.), and the depth o the water relativeto the birds legs. Te specic location oeach individual or group was recorded onan aerial photo. Tese data were then en-tered into a Geographic Inormation System(GIS) or analysis.

Figure 1. Blna Lagn an vcnty.


A ne scale census o herons and egrets on Bolinas Lagoon

Local Values

by Emiko Condeso


10/16

Figure 2. dtbtn n an gt n Blna Lagn n t nn-bng (tangl) an bng (ccl) an (Agt 2005 t Fbay 2006 an Macjly

2006, pctvly). T z ymbl pnt t nmb nval n a gp agng b (gp amt 100 m). T g pnt cmlatv t

lagn by t pc v n calna ya an nt pnt t nmb b bv at any n pnt n tm.



11/16

Great Egrets are a constant presenceon the lagoon during the non-breedingseason, typically numbering less than tenindividuals at any given time (Figure 2).During the breeding season, however, thenumber o Great Egrets observed on thelagoon increases dramatically. Tis increaseis consistent with the number o active nestsat Picher Canyon. Great Blue Herons are notas abundant as either Great Egrets or SnowyEgrets on Bolinas Lagoon, nor do they nestin great numbers at Picher Canyon (Figure2). Colonies o Great Blue Herons are typi-cally small throughout the Bay Area (Kellyet al. 2006). Snowy Egrets have thus ar beenonly occasional nesters at Picher Canyon;however, they make great use o the lagoonduring the non-breeding season. During ourcensus periods as many as 60 Snowy Egrets

were observed on the lagoon at once (Figure2). Snowy Egret use o the lagoon dropso sharply aer the onset o the breedingseason, when they are presumably tied tooraging areas closer to their breeding sites(Figure 2; Kelly, 2008).

During both the breeding and non-breeding seasons, all species tended to con-gregate at creek deltas and slough margins.Great Egrets are more widely distributedthroughout the lagoon than the other spe-cies observed, which may be related to theirabundance and oraging behavior (Figure3). We recorded Great Egrets in the center othe lagoon and the area south o the moutho Pine Gulch Creek (Figure 1), placesboth Great Blue Herons and Snowy Egretstended to avoid. During our study period,Great Egrets oraged individually or in small

groups. Great Blue Herons were seldomound in groups, and they avored the PineGulch Creek delta, the area around KentIsland, and the east shore o the lagoon nearthe channel (Figure 3). Tis is consistentwith their solitary nature and a ew studiessuggesting that Great Blues tend to return to

specic eeding areas (e.g., Dowd and Flake,1985). During the non-breeding season,large groups o Snowy Egrets also concen-trated in areas o the lagoon where reshwater drains into the estuary, such as themouth o Pine Gulch Creek. Individuals andsmall groups o Snowy Egrets were ound inmost o the shallower parts o the lagoon.During the breeding season, Snowy Egretsoraged in smaller groups or alone, thoughgroups o 510 birds could still be ound.

Tough extensive use o Bolinas Lagoonby herons and egrets is well known, un-

derstanding and quantiying what makeshabitat in this estuary preerable is actuallyquite difcult. Te inormation presentedhere is part o a work in progress, and areaso the lagoon with relatively little observeduse may still be very important to the birdsat times when they were not observed.Precisely what is needed to support healthypopulations o herons and egrets is a ques-tion oen asked o conservation biologists,yet supportive data are usually lacking. ACRhas begun to address this question or Bo-linas Lagoon, and it is our hope that uturework will allow us to develop a more generalunderstanding o these species habitatneeds. Ultimately, such inormation maybe important in evaluating and protectingwetland quality wherever herons and egretsoccur.

Reerences cited

Dowd, E. M. and L. D. Flake. 1985. Foraging habits andmovements o nesting Great Blue Herons in a prairie riverecosystem, South Dakota. Journal o Field Ornithology56(4):379-387.

Kelly, J. P., K. Etienne, C. Strong, M. McCaustland, and M.L. Parkes. 2006. Annotated atlas and implications orconservation o heron and egret nesting colonies in theSan Francisco Bay area. ACR echnical Report 90-3-17,Audubon Canyon Ranch, P.O. Box 808, Marshall, CA

94940. 236 pp.Kelly, J. P., Stralberg, D., Etienne, K., and M. McCaustland.

2008. Landscape inuence on the quality o heron andegret colony sites. Wetlands 28:257-275.

Shuord, W. D., Page, G. W., Evens, J. G., and L. E. Stenzel.1989. Seasonal abundance o waterbirds at Point Reyes: acoastal perspective. Western Birds 20:137-265.


Figure 3. Abnanc (pn ymbl) Gat egt, Gat Bl hn, an snwy egt n Blna Lagn

an t nmb nt (ll ymbl) ac pc bv at t Pc Canyn ny, Abn Canyn

ranc, by cn at (Agt 2005jly 2006).


12/16

page # THE ARDEID 2008page 10 THE ARDEID 2009

Numerous creeks carve the anks oMount amalpais, in Marin County,as they snake toward the Pacic Ocean.Te areas topography causes some o thesestreams to ow into San Francisco Bay andsome directly into the Pacic Ocean, whileothers enter Bolinas Lagoon beore reachingthe sea. Although all o the creeks, includingthose that carved the canyons o the BolinasLagoon Preserve (BLP), are part o thegreater Mount amalpais watershed, theyorm distinctive sub-watersheds that havedierent stewardship needs (Figure 1).

Each o the our canyons that compriseBLP is drained by a separate creek owinginto Bolinas Lagoon. Te north- and south-acing slopes o each canyon host dierentspecies, due to numerous actors includingtheir exposure, slope, and soil type. Tenorth-acing slope o Volunteer Canyon isdominated by conierous orest, whereas

the canyons south-acing slope is mostly amixture o oak woodland andchaparral. Between canyons,these dierences become evenmore pronounced. For example,the Caliornia sagebrush-domi-nated south-acing slope in Gar-den Club Canyon is a dramaticcontrast to the redwood orest

just over the ridge in the north-acing Pike County Gulch. Tis

varied topography is part owhat allows or the incredible

oristic diversity within thepreserve. Yet it also provides achallenge: which plant popula-tions ought to be the source orplants used in ACRs revegeta-tion eorts?

Ecologists presume that,or most species, gene owgenerally ollows the pathwayscreated by water, with seedsrom upland populations carrieddownstream by gravity or rain-all events. Additionally, windssweep up or down the canyons,

creating paths or gene ow in wind-pol-linated species. However, this watershedmodel o gene ow does not hold true orall species. For example, ruits and berriesare consumed by birds and mammals thatare able to disperse seeds across watershedsand regions. Because o the diversity omechanisms or pollination and dispersal,the concept o a geneshed is a useul wayto view the genetic range o a plant species.Unique or every species, a geneshed canbe conceptualized as the area over whicha species genetic material can successullytravel. A coconut may be able to traverse theentire Pacic Ocean, whereas a buckeye inVolunteer Canyon may only roll a ew eetrom its source tree. ACRs Habitat Protec-tion and Restoration sta use the concept ogenesheds to think beyond sub-watershedswhen considering how ar aeld to roamwhen collecting seed or our restoration

projects.

Reerence sites and species selectionIn 2006, Audubon Canyon Ranch started

work on the Four Canyons Restoration Proj-ectthe restoration o ormer human-useareas to wild habitat at BLP. Our restorationsites are primarily located in canyon bot-tomlands and riparian oodplains, which

have been aected by use as parking lots,building areas, and storage sites or equip-ment and materials used on the preserve.Tese previous disturbances made the landsusceptible to invasion by weeds that com-pete with native plants or space, sunlight,and nutrients.

o select our planting palette, we identi-ed reerence sites with similar character-istics to our restoration site and used theirspecies diversity to inorm our projectdesign (Figure 2). One o our goals is or oursites to re-establish habitat capable o pro-

viding abundant resources to native insect,

bird, amphibian and mammal species pres-ent at BLP. By including groundcover, grasses, shrubs, and trees,we can ensure that there will bemultiple layers o vegetation thatcreate a variety o habitats. Incor-porating plants that set seeds orproduce berries enhances avail-able ood resources or wildlie.Planting insect-pollinated plantsprovides valuable resources orpollinators. Additionally, by us-ing plants that vary in the timing

o their seasonal reproductivecycles, rom early spring annualsto woody perennials that owerin late autumn, our restorationsites will be able oer diverseresources throughout the year.

Once we have determinedwhat species to grow or eachsite, seed collection can begin.Most seeds do not mature untilmid-summer; they cannot beplanted in the same year theyare collected, because they needmore time to grow to a stage

How seed collection infuences genetic diversity in ecological restoration

Growing Diversity

by Hillary Sardias

Figure 1. T ck tat cat t canyn t Blna Lagn Pv

gnat n t ank Mt. Tamalpa an tmnat n t Blna Lagn. Ty

a paat by tp g tat lat tm m n ant. F tatn

pp, w tat ac canyn a t wn tnct b-wat Blna Lagn

an mantan t gntc ntgty by ng plant gwn m cllct wtn

t tnatn canyn.


13/16

2008 THE ARDEID page #where they have adequate resources to sur-

vive outplanting. In order to properly time aplants readiness, collection must occur one-and-a-hal years prior to the planned project,with seeds sown in pots during the springpreceding the winter planting season. Excep-tions include annuals, early-maturing native

grasses, and seeds that are directly sown intosites; these can be collected the spring beoreplanting, or in the case o a late-bloom-ing species, sown directly into sites as theymature in the late all/early winter.

Principles o seed collectionA major concern that conservation proj-

ects conront is how to collect sufcient seedto achieve restoration goals without over-harvesting rom native plant populations.o address this issue, native plant nurserieshave created the ollowing three guidelines

or seed collection (adapted rom Young2007, Proposed Seed Collection Guidelines,Golden Gate National Recreation Area):

1. Te Five Percent Rule: Collect no morethan 5% o the available seed rom any spe-cies in a specic area or rom any particularindividual.

2. Te Rule o en: Collect rom as manyplants o each species as possible throughouta collection area, and never rom ewer thanten plants.

3. Te Law o Space and ime: Collectthroughout the species geneshed; collectseveral times throughout the seed ripeningperiod.

Te Five Percent Rule is based upon nd-ings by Menges and others at the ArchboldBiological Station, Lake Placid, Florida, whostated that less intense, requent harvests aresaer than more intense, inrequent harvests.Tey ound that high rates o seed removal(over 50%) signicantly reduced populationgrowth rate and increased probabilities oextinction in some species. By collectingonly a small portion o the seeds available,we can help wild populations to persist,prosper, and provide genetic material or

uture projects. Additionally, at BLP we col-lect seeds rom populations over a series oyears, making sure that our eorts in a givenyear do not cause major demographic shisin native plant populations.

Te Rule o en ensures that particularversions o genes (alleles) rom only a ewplants do not dominate the population inrestored sites (Knapp and Rice 1994; Resto-ration and Management Notes 12:4045).Harvesting seed rom a variety o dierentindividuals helps to balance their geneticcontributions to the population. It is or

this reason that seed collectors try not to

discriminate against plants that donot appear to be as robust as otherindividuals. Natural populations oplants consist o a mixture o indi-

viduals that vary in size, height, andso on, due to both genetic and envi-ronmental eects. Tereore, the

appearance o a plant at a particulartime or place may not be a goodmeasure o its genetic value.

Te Law o Space and ime isa guideline that encourages seedcollecting at several locations othe geneshed and at dierent timesthroughout a species seed ripeningseason. By ollowing this practice,collectors have a better chance oencountering early- and late-ower-ing varieties. Because natural popu-lations contain plants that bloom

at dierent intervals, this measurehelps ensure that a seed sample re-ects the natural variability presentin the wild population. By collectingrom throughout a plants geneshed,we can increase the chances oencountering that species in dier-ent environmental conditions ando capturing adaptations associatedwith such variation.

All these measures help ensurethat our seed inventory reects the diversitycontained within wild populations, withoutharming these populations. However, allthese conditions beg the question: Why isdiversity important?

Diversity sustains local adaptationsGenetic variation is essential because it

allows populations to adapt and evolve tochanging conditions. I there is not su-cient genetic variation, populations maybe unable to withstand changing conditionsthat limit their survival or reproduction,potentially leading to extinction. Limitedresources within a gene pool can lead to acondition known as inbreeding depression.

Inbreeding depression can make a popula-tion vulnerable to deleterious recessiveallelesgene orms that are normally hid-den or neutral in large populations but canproduce dangerous traits in small popula-tions i there is a strong likelihood o matingbetween genetically similar individuals(Figure 3). Tese traits may lower a plantsability to survive or reproduce and can causea small population to become extinct.

Te opposite o inbreeding depressionis outbreeding depression. Outbreedingdepression occurs when oreign traits dilute

or overwhelm local traits that evolved to

enhance survival in certain conditions. Bycrossing populations that have not tradi-tionally interbred, new alleles introducedrom a dierent environment might result intraits that decrease a plants ability to surviveor reproduce (Figure 3).

By including seeds rom dierent loca-tions within a local populations geneshed,seed collectors attempt to decrease thepotential or inbreeding or outbreeding,while optimizing localized genetic variation.Local adaptations are important, becausethey may coner traits that could contributeto the resilience o native plants in restora-tion sites. For example, competitive traits,such as early germination, may actually

enhance growth during the seedling phase,when competition with non-native speciesis typically most pronounced (Leger 2008;Ecological Applications, 18:12261235).Because o the widespread abundance onon-native and invasive species in coastalCaliornia ecosystems, competitive traitscould prove essential or the continuedsurvival o some plants. By collecting seedsdirectly rom a site slated to be restored androm other sites within a species geneshed,we can ensure that localized adaptations arepresent.


Figure 2. rtatn t (tp) an acat nc t

(btm) n Gan Clb Canyn.


14/16

page # THE ARDEID 2008Climate change

Although there are numerous predic-tions concerning the eects o climatechange, none o the models reliably describehow global warming patterns will actuallymaniest. Collecting seeds rom plants thatinhabit the local extent o their geneshed(such as at dierent altitudes and aspects)could help protect species rom climatechange. For example, suppose a certainplant typically grows in shade but occa-sionally is ound in sunny, exposed areas:by using seed rom individuals growing insunnier areas, we might be able to enhancethe populations likelihood o surviving aclimate shi toward drier conditions. Suchcrosses are risky, however, because theymight lead to outbreeding depression, so acautious approach may be critical. Tere-ore, the three guidelines or seed collection

(above) should result in plants with variedgenetic stock that are capable o establishingin the short-term and adapting to uncertainuture conditions.

Even i the eects o climate changeare not signicant, weather and rainallcan be extremely erratic. Random naturalevents can have damaging eects on small,susceptible populations. For example, two

early winters in a row could thwart thematuration o seeds and prevent a rare plantrom replenishing its seed bank. I random,harmul events continue, the plant popula-tion could be threatened with extinction. Bymaintaining genetic diversity within restora-tion sites, we may promote the presence oresilient individuals to insulate the popula-tion against unpredictable weather patterns.

Toward balanceaking all o the aorementioned actors

into consideration is tricky, because wedo not want to risk incorporating nativeplants that are not capable o surviving inour restoration sites, causing gaps that mayallow invasive species to re-colonize. Inorder to prevent such a scenario, we moni-tor the survivorship o each plant species.I particular species do not survive in a site,we can replace them with dierent species.Te inormation we gather enables us tomeasure our progress and alter any methodsthat are not working. Tis exible and com-prehensive approach avors the long-termsuccess o our restoration sites.

Trough thoughtul seed collection,careul project design that incorporates aregard or genetic diversity, and a strategyor adaptively improving our work, the

Habitat Protection and Restoration team atAudubon Canyon Ranch is restoring the de-graded areas at the Bolinas Lagoon Preserve.Applying the principles o diversity to ourprojects helps ensure that plant communi-ties we conserve are resilient, healthy, andcapable o adapting to the multiplicity oconditions the uture may bring.


Figure 3.A pnt a nmal mnant vn

a gn (alll), a pnt a lt cv

alll, anApnt a mnant alll m a gn

pplatn. dmnant alll typcally pp cv

alll, wv nbng nca t pbablty

tat cv alll wll b xp m qntly,

wc cl am t pplatn. on t t an,

tbng cl ntc alll tat cl av

bncal oraml ct, pnng pn t

vltnay ty t gnal pplatn.

Eects o invasive species on nitrogen retentionand other issues in the ecology and restorationo coastal prairie. j Cbn, unn Cllg.

Carbon addition and mowing as restorationmeasures in a coastal Caliornia Grassland.By sanl, uC Bkly.

Ecological indicators in West Coast estuaries.stvn Mgan, san Ann, ant, Pacc etan ecytm incatrac (Peeir) Cntm [www-bml.

cav./p].Long-term monitoring o the Giacominiwetland. Lan Pan, Pnt ryNatnal sa.

Analysis o sedimentation in natural andrestored marshes. Lan Pan, Pntry Natnal sa.

Factors causing summer mortality in Pacifcoysters. F Gfn, uC dav Bga ManLab.

A comparison o carbon cycling and materialexchange in grasslands dominated by nativeand exotic grasses in northern Caliornia. La

Ktn, uC Bkly.

Black Brant counts at Drakes Estero, TomalesBay and Bodega Bay. r hg, santa ra,Calna.

Strophariaceae o Caliornia. Pt Wn,dnn dan, san Fancc statunvty.

Eects o landscape context and recreationaluse on carnivores in northern Caliornia. saar, uC Bkly.

Impact o an introduced plant pathogen on

Lyme disease ecology. Cyl Bgg anAnw sw, uC Bkly.

Impacts o Wild Turkey(Malag galpav) onnative aviauna in northern Caliornia. AnglaGllngam, dk unvty/Calna statPak.

Eects o planktivorous fsh predation onlarvae release patterns o estuarine crabs. Lramn, unvty Pgt sn.

Investigtion o ossil Olivella (a marine snail)rom the Millerton Formation at Toms Point,

Tmal Bay. danl M, u.s. Glgcalsvy.

A camera trap survey o mammals and birdsat Audubon Canyon Ranch, rc Tnaza,unvty t Pacc, an C Wmm,Calna Acamy scnc.

Non-fre and non-soil controls o the chaparral/grass boundary in Caliornia. Mac Cl, uCdav.

Field verifcation o habitat connectivity modelsor the Mayacamas Mountains ecosystem.jtn Ktz, saa r, an Ana

Mnln, uC Bkly.Initial Suyrvey o vegetation used or questingbyix pacc (Ac: ixa). MatnCat, Calna dpatmnt haltsvc, Vct-bn da sctn.

Tidewater goby assessment and protectionactivities associated with the Giacomini RanchRestoration Project. dan Fng, Gln GatNatnal rcatn Aa.

Visiting Investigators

Audubon Canyon Ranch hosts graduate students and visiting scientists who rely on the undisturbed, natural conditions of our sanctuariesto conduct investigations in conservation science.

AAA


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2008 the Ardeid page 13

Picher Canyon Heron andEgret Project The ates oall nesting attempts at ACRsPicher Canyon heronry havebeen monitored annuallysince 1967, to track long-termvariation in nesting behavior andreproduction.

Tomales Bay ShorebirdProject Since 1989, we haveconducted annual shorebird

censuses on Tomales Bay. Eachcensus involves six baywidewinter counts and one baywidecount each in August and Aprilmigration periods. A team o1520 volunteer eld observers isneeded to conduct each count.The data are used to investigatewinter population patterns, localhabitat values, and implicationsor shorebird conservation.

A Natural ResourcesManagement Plan or ModiniIngalls Ecological PreserveAudubon Canyon Ranch hassigned a collaborative, plannedgiving agreement with Jimand Shirley Modini to acquire1,725 acres in northern SonomaCounty. The property, to beknown as the Modini IngallsEcological Preserve, has been inthe Modini Ingalls amily since1867. This remote, undisturbedlandscape is a rich blend ooak woodlands, pine orests,perennial grasslands, chaparral,serpentine outcrops, andwild streams. Sherry Adams is

developing a comprehensiveplan or long-term stewardship,including eld surveys to assessbiological values, cultural history,and management needs. Thework is being made possiblethrough generous support

provided by Jim and ShirleyModini. The completed plan willinclude implications or regionalconservation in the centralMayacamas Mountains (seephoto on back cover).

Tomales Bay WaterbirdSurvey Since the winter o198990, teams o observershave conducted winter waterbirdcensuses rom survey boats onTomales Bay. The results provideinormation on habitat valuesand conservation needs o more

than 50 species. We are currentlyinvestigating trends in speciesabundances and relationshipswith Pacic herring roe asimportant ood or winteringwaterbirds in Tomales Bay.

North Bay Counties Heronand Egret Project Annualmonitoring o reproductiveactivities at all known heronand egret nesting colonies inve northern Bay Area countiesbegan in 1990. We are currentlyinvestigating the efects o

landscape habitat patterns onnesting herons and egrets. ACRs250-pageAnnotated Atlas andImplications for the Conservationof Heron and Egret NestingColonies in the San Francisco BayArea includes an analysis o theregional status and trends oherons and egrets and providesindividual accounts o all knownheronries in the area (www.egret.org/atlas.html). We havealso developed a reerence thatuses Google Earth to show thelocations and status o northern

Bay Area heronries (www.egret.org/googleearth2.html).

Impacts o Wild Turkeys onForest Ecosystems DanGluesenkamp is conducting astudy to experimentally measurethe efects o ground oraging byinvasive, non-native Wild Turkeyson vegetation and invertebratesin the orest ecosystem oBouverie Preserve.

Four Canyons Project ACRsBolinas Lagoon Preserve containsour canyons that drain thewestern slope o Bolinas Ridge.We are restoring the naturalcomplexity o native vegetationin the lower reaches o these

canyons, repairing disturbed sites,and eradicating or controllinginvasive plant species. Nativeplant propagation acilities inVolunteer Canyon are being usedto grow locally collected plantmaterials or restoration.

Monitoring and Controlo Non-Native Crayfsh Jeanne Wirka and others arestudying the distribution onon-native signal craysh(Pacifastucus lenisculus) in StuartCreek at Bouverie Preserve and

investigating the use o barriersand traps to control the potentialimpacts o craysh on nativeamphibians and other species.

Highway-Generated NitrogenDeposition in Vernal WetlandsEnhanced availability onitrogen near highways mightacilitate invasion by non-nativeplant species in sensitive vernalwetlands. Dan Gluesenkamp,Stuart Weiss, and Jeanne Wirkaare quantiying the potentialefects o highway-generated

nitrogen deposition on SonomaValley vernal pools.

Plant Species Inventory Resident biologists maintaininventories o plant speciesknown to occur on ACRs TomalesBay properties and at Bouverieand Bolinas Lagoon preserves.

Annual Surveys and Removalo Non-Native Spartina andHybrids In collaboration withthe San Francisco Estuary InvasiveSpartina Project, Emiko Condesoand Gwen Heistand coordinateand conduct comprehensive eldsurveys or invasive, non-nativeSpartina in the shoreline marsheso Tomales Bay and BolinasLagoon.

Monitoring and Eradicationo Perennial Pepperweed inTomales Bay Invasive, non-native pepperweed (Lepidiumlatifolium) is known to quicklycover oodplains and estuarinewetlands, compete with nativespecies, and alter habitatvalues. We are using a variety o

methods to remove and monitorthe rst known inestations inTomales Bay and, hopeully,prevent urther invasion.

Saltmarsh Ice Plant RemovalWe have eradicated non-native ice plant rom marshes

and upland edges at TomsPoint on Tomales Bay, althoughmanagement to removeresprouts and new patchescontinues. Native vegetation hasrecruited into areas where iceplant was once dominant.

Eradication oElytrigiapontica ssp.ponticaElytrigiais an invasive, non-nativeperennial grass that orms densepopulations in seasonal wetlands.At Bouverie Preserve, we areeliminating a patch oElytrigia

using manual removal, lightstarvation/solarization (blackplastic tarps), and herbicide spottreatments o outlier patches.

Nest Boxes Tony Gilbertmaintains Western Bluebirdnest boxes in the CypressGrove grasslands. Rich Stallcupmaintains several Wood Ducknest boxes along Bear ValleyCreek in ACRs Olema Marsh.

Restoration o Coastal Dunesby Removal oAmmophila

arenariaAmmophila arenariais a highly invasive, non-nativeplant that alters the topographyand unction o coastal dunes.Removal oAmmophila atToms Point, on Tomales Bay, ishelping to protect native speciesthat depend on mobile duneecosystems.

Vernal Pool Restoration andReintroduction o ImperiledPlants Dan Gluesenkamp,Jeanne Wirka, and SherryAdams are restoring habitat

conditions in the vernal pools atBouverie Preserve. The projectincludes the removal o invasiveplants and re-establishmento the ederally listed Sonomasunshine (Blennospermabakeri) and Caliornia specieso conservation concern dwardowningia (Downingia pusilla).The work involves manual efortby volunteers, propagation andplanting o native plants, use oprescribed re, cattle grazing, andmonitoring o vegetation andhydrology.

In Progress:

project updatesCurrent projects by AudubonCanyon Ranch focus on thestewardship of sanctuaries,

ecological restoration, andissues in conservation science.


16/16

Te Ardeidis published annually by Audubon Canyon Ranch as an oering to Conservation Science

and Habitat Protection feld observers, volunteers, and supporters. To learn more about this program

and how to support Audubon Canyon Ranch, please contact the Cypress Grove Research Center

([email protected] or 415.663.8203) or ACRs headquarters ([email protected] or 415.868.9244).

2009 Audubon Canyon Ranch. Printed on recycled paper.

Managing Editor, John Kelly. Layout design by Claire Peaslee. www.egret.org

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Documents

The Ardeid Newsletter, 2009 ~ Audubon Canyon Ranch