Conservation Science and Habitat Protection at

THE Ardeid

◗ Bouverie Preserve

wetlands dynamics

◗ parental wisdom

nesting Great Egrets

◗

heron and egret surveys

◗ growing diversity

seed collection for

ecological restoration 2009 the Ardeid 2009

In this issue Fountain of Fountains: Exploring the dynamics of seasonal wetlands at the Bouverie Preserve ◗ by Sherry Adams and Arthur Dawson page 1 The Ecology of Parental Wisdom: Strategic nest attendance by Great Egrets ◗ by John P. Kelly page 4 Local Values: A fine scale census of herons and egrets on Bolinas Lagoon ◗ by Emiko Condeso page 7 Growing Diversity: How seed collection influences genetic diversity in ecological restoration ◗ by Hillary Sardiñas page 9 Cover: A Snowy Egret “foot stirring” to find prey. The number of foraging Snowies in Bolinas Lagoon increases during fall and winter. ◗ Photo by Philip Loring Greene. Ardeid masthead Great Blue Heron ink wash painting by Claudia Chapline.

Audubon Canyon Ranch Staff The Watch Administration Volunteers for ACR research or habitat restoration projects since The Ardeid 2008. Please call (415) 663-8203 if your name should have been included. Skip Schwartz, Executive Director Project Classifications B—Bouverie Stewards s C—Crayfish Research Projects John Petersen, Associate Director F—Four Canyons Restoration Project s H—Heron and Egret Project s N—Newt Stephen Pozsgai, Controller Monitoring s P—Habitat Protection s S— Shorebird Census s Yvonne Pierce, Administrative Director and V—Vernal Pool Restoration s W—Tomales Bay Waterbird Census Bolinas Lagoon Preserve Manager Jared Abranson (N), Nancy Abreu (H), Ken (F), Stephanie Lennox (H), Robin Leong Bonnie Warren, Administrative Manager, Cypress Grove Ackerman (B,P), Julie Allecta (P), Jason Allen (H), Eileen Libby (H), Joan Lippman (H), Research Center (C,N), Sarah Allen (S,W), Janica Anderson Marcus Lipton (P), Wayne Little (H), Bert Nancy Trbovich, Administrative Manager, Bouverie (H), Jennie Anderson (H), Norah Bain (H,S), Lombino (P), Carolyn Longstreth (H,S,W), Preserve Brian Bartsch (F), Katy Baty (W), Tom Baty John Longstreth (H,S,W), Anthony Lucchesi Suzanna Naramore, Administrative Assistant, Bolinas (W), Cheryl Belitsky (H), David Belitsky (N), David Mac Hamer (H), Pat Macias (H), Jennifer Benham (F), Phyllis Benham (H), Lyn Magill (B), Charlotte Martin (P), Lagoon Preserve (W), Shelly Benson (W), Evelyn Berger (P), Richard Martini (F), Pat McCaffrey (P), Judy Leslie Sproul, Receptionist/Office Assistant, Bolinas Lagoon Louise Bielfelt (B,P), Louise Bielfelt (N), McCarthy (W), Mark McCaustland (H,W), Preserve Sherm Bielfelt (B,P), Gay Bishop (S), Stephanie Dave McConnell (H), Matthew McCrum (F), Bishop (H), Anna Bjorquist (N), Giselle Alexandra McDonald (S), Diane Merrill (H), Development Block (H), Eileen Blossman (F), Len Blumin Jean Miller (H), Sarah Minnick (P,W), Jim Didi Wilson, Director of Development and (F,H,S,W), Patti Blumin (H), Ellen Blustein Moir (C), Corinne Monohan (P), Stephen Communications (H,S), Janet Bosshard (H), Bruce Bowser (F), Moore (H), Ian Morrison (W), Dan Murphy Connie Bradley (F), Anna Marie Bratton (S), Joan Murphy (S), Kim Neal (H), Dexter Cassie Gruenstein, Director of Major Gifts (F), Melissa Brockman (H), Susan Bundschu Nelson (N), Len Nelson (H), Wally Neville Jennifer Newman, Development Manager (P), Phil Burton (H), Denise Cadman (H), (H), Terry Nordbye (S,W), Grace Noyes (P), Britt Henke, Development Assistant Miriam Campos (F), Barbara Carlson (P), Pat O’Brien (N,P), Shiela O’Donnell (H), Paula Maxfield,Publicist Tom Cashman (H), Ann Cassidy (H), Robin Tony Paz (F), Emily Pellish (P), Brittany Chase (N), Mae Chen (F), Dave Chenoweth Penoli (P), Genevieve Perdue (P), Louis Petak Science and Education (F), David Ciardello (N), Careana Clay (F), (W), Kate Peterlein (S), Emma Pierson (N), John Kelly, PhD, Director of Conservation Science and Brian Cluer (H, pilot), George Clyde (H,W), Alison Pimentel (P), Sally Pola (P), Lauren Mary Ann Cobb (F), Hugo Condeso (H,W), Popenoe (N), Grace Pratt (H), Peter Pyle (S), Habitat Protection Judith Corning (W), Patricia Craves (F), Lara Rachowicz (H), Jeff Reichel (H), Linda Daniel Gluesenkamp, PhD, Director of Habitat Protection Sylvia Crawford (P), Brian Cully (F), Sharon Reichel (H), Don Reinberg (S), Margot Reisner and Restoration (HPR) Dankworth (C,N), Karen Davis (H), Melissa (F), Arlene Reiss (F), Maria Rivera (H), Will Sherry Adams, Biologist, Modini Ingalls Ecological Preserve Davis (H), Jaime Della Santina (F), John Robinson (F), Jordon Rosado (N), Glenda Dineen (H), Caroline Dutton (H), Bob Dyer Ross (B), Christine Rothenbach (H,P,S), Ellen Emiko Condeso, Biologist/GIS Specialist, Cypress Grove (H), Joe Eaton (F), Dexter Eichhorst (F), Zach Sabine (H), Stacey Samuels (P), Jack Sandage Research Center English (F), Rick Ernst (H), Jules Evens (S,W), (F), Marilyn Sanders (H), Diana Sanson (N,P), Gwen Heistand, Co-director of Education and Resident Mark Fenn (H), Binny Fischer (H,W), Leslie Sharon Savage (C), Phyllis Schmitt (C,H,N), Biologist, Bolinas Lagoon Preserve Flint (W), Jobina Forder (B,P), Kevin Fritsche Alice Schultz (H), Harold Schulz (H), Theresa (H), Dennis Fujita (B,P), Jennifer Garrison Schulz (P), John Schwonke (B), Lindsey Jeanne Wirka, Co-director of Education and Resident (H), Daniel George (S,W), Rebecca Geronimo Segbers (P), Steve Shaffer (H, pilot), Heather Biologist, Bouverie Preserve (P), James Gibbs (F), Marjorie Gibbs (F), Shannon (F), Richard Shipps (P), Marjorie Bob Baez, Helen Pratt Field Biologist Anthony Gilbert (H,S), Beryl Glitz (H), Dohn Siegel (H,W), Jane Sinclair (P), Paul Skaj (W), Hillary Sardiñas, HPR Projects Leader, Marin Glitz (H), Pedro Gomez (N), Johann Grayson Elliot Smeds (C,N), Austin Smith (N,P), Joe (N), Philip Greene (H), Marty Griffin (W), Smith (W), Joseph Smith (W), Pat Smith (H), Cassandra Lui, HPR Field Technician Daniel Grubb (N,P), Sophia Grubb (C,N,P), Ben Snead (H,W), John Somers (S,W), Nollene Claire Seda, Weekend Program Facilitator, Bolinas Lagoon Brian Gully (V), Alyssa Hall (P), Karlene Hall Sommer (N), Robert Speckels (H), Bob Preserve (P), Madelon Halpern (H), Lauren Hammack Spofford (H), Sue Spofford (H), Jude Stalker (H), Fred Hanson (S), Roger Harshaw (S,W), (W), April Starke Slakey (P), Jean Starkweather Land Stewards Alison Hastings-Pimental (P), Will Haymaker (H), Serena Stoepler (P), Michelle Stone (C), Bill Arthur, Bolinas Lagoon Preserve (P), Guy Henderson (F), Andrea Hernandez Tina Styles (H), Ron Sullivan (F), Lowell Sykes David Greene, Cypress Grove Research Center (C), Earl Herr (B), Diane Hichwa (H), Vicky (H), Judy Temko (H,S), Janet Thiessen (H), Hill (P), Maddy Hobart (N), Joan Hoffman Eric Thistle (P), Gwendolyn Toney (S,W), John Martin, Bouverie Preserve (H), Ingrid Hogle (P), Ken Horner (F), Roger Vicki Trabold (P), Mike Tracy (N,P), Nick Matej Seda, Maintenance Assistant, Bolinas Lagoon Hothem (H), Lisa Hug (H,S), Merle Hunter Tracy (C,N,P), Kayla Trbovich (P), Thomas Preserve (F), Ellie Insley (V), Scott Jarvis (P), Victoria Tucker (H), Gerrit Van Sickle (N), Diane Jarvis (P), Bobbie Jenkins (N), Taylor Jensen Voorhoeve (H), Sue Walker (P), Tanis Walters Research Associates (N), Rick Johnson (H), Linda Judd (N), (S), Wes Weathers (H), Grace Wellington Jules Evens Gail Kabat (W), Guy Kay (H), Audrey King (C), Casey Wells (P), Jim White (H,W), Dave (H), Doug King (H), Emma King (P), Andy Whitridge (F), Adele Wikner (H), Ken Wilson Helen Pratt Kleinhesselink (F), Ellen Krebs (H), Carol (W), Linda Wilson (N), David Wimpfheimer Rich Stallcup Kuelper (F,S), Dawna La Brucherie (P), Joan (F,H,S,W), Dylan Witwicki (C,N), Bill Wolpert Lamphier (H,S,W), Brett Lane (H), Frieda (W), Carol Wood (P), Patrick Woodworth Larson (N), Dakota Lawhorn (N), Scott (H,S,W), Bailey Wyate (N) Lawyer (C), Galen Leeds (S), Lamar Leland 2009 THE ARDEID page 1

Exploring the dynamics of seasonal wetlands at the Bouverie Preserve Fountain of Fountains

by Sherry Adams and Arthur Dawson

Figure 1. A measuring tape is stretched (from center foreground) across wetland 5A to prepare for vegetation monitoring. Meadowfoam (Limnanthes douglasii ssp douglasii), a wetland generalist, is the dominant species.

We know that the wet- lands of Sonoma Valley have gone through major changes in the last 200 years. In the very first written description of Sonoma Valley, Father Jose Altimira remarked on the many springs, ponds, marshes, and creeks on the valley floor. Water was noticeably more abundant here than anywhere else he went, including Petaluma, Napa, and Suisun valleys. Altimira was so impressed by this abundance that he nick- s

am named Sonoma Valley “un d a manantial a manantiales” or “a fountain of fountains.” The sherry abundance of water was one of the reasons he chose to very day, 15,000 cars pass within view of look quite different from one year to the establish his mission here. Ean especially valuable area of habitat at next. For example, in most years the Bouv- The largest wetland was in the upper ACR’s Bouverie Preserve in Sonoma Valley, erie wetlands are home to over 100,000 in- part of the valley. Though it was called yet the area is rarely visited, since no trail dividuals of the rare vernal pool wildflower, the Kenwood Marsh, it was really a chain leads to it. This habitat fluctuates wildly dwarf downingia (Downingia pusilla), but in of marshes and wetlands covering about through the course of the year. During the 2009, due to the unusual winter precipita- 400 acres and stretching five miles from winter rains, plants germinate and insects tion pattern, only about 14,000 were present. the watershed boundary (Pythian Road), and other tiny invertebrates enter into the Like other annual plants, this one has a large through present-day Kenwood, to near aquatic phase of their lives. In spring these seed bank and is expected to thrive again Dunbar School in Glen Ellen. In fact, this spots slowly dry out, wildflowers bloom, when the conditions are supportive. This marsh complex extended all the way to the grasses grow, and frogs hop off on new legs. sort of interannual variation is expected in edge of modern-day Santa Rosa, suggesting This is followed by complete desiccation, the natural world. that a subsurface connection existed—and with a handful of specially adapted plants, Each time we consider changes at a dif- may still exist—between the Sonoma Creek such as the aromatic vinegar weed (Tricho- ferent temporal scale, the patterns we have and Santa Rosa Creek watersheds (Anony- stema lanceolatum), growing and flowering previously focused on may fade from view, mous 1837). Groundwater was exceptionally in the heat of summer. This dynamic habitat and new ones become apparent. If we take high throughout this part of Sonoma Valley. is the wetlands of Lower Field of the Bouv- one more step back, to consider changes Some of the Kenwood Marsh probably held erie Preserve (Figure 1). within a timeframe of decades to centuries, surface water throughout the year (Boggs In addition to the changes this habitat what patterns overshadow these well-known 1861). By catching runoff from winter goes through in the course of a year, it can yearly cycles and year-to-year fluctuations? storms and releasing it over many months, page 2 THE ARDEID 2009

type quickly fills when it is raining, and the water level drops between precipitation events. This is consistent with the expla- nation that these wetlands have a mostly impermeable clay hardpan bottom (as with vernal pools). Rainwater collects in them and then evaporates (Figure 2, dashed lines). The second type of wetland never holds much water (less than 10 cm), and the water level rises only slightly in response to rain events, dropping slowly afterwards (Figure 2, solid lines).

Vegetation In the first type of wetland, the one with a flashier hydrograph, or greater up- and-down swings in charted water level, characteristic vernal pool species were present. In the second type of wetland, the one with lower, more stable water levels, characteristic vernal pool species were not found. Instead, these areas were dominated Figure 2. Maximum water depths at several wetlands during winter, 2007–2008. Wetlands with a dashed by grasses and grass-like species (sedges and line have greater swings (flashier hydrograph) than those with a solid line. rushes). After mowing or grazing, we saw some native wildflowers in this second type the Kenwood Marsh acted as a sponge, look for evidence of silt accumulation, we of wetland, but these were not vernal pool reducing downstream flooding and increas- asked Dr. Steve Talley, a soil scientist with specialists. Rather, they were wetland gen- ing the flow of Sonoma Creek during the extensive vernal pool experience, to investi- eralists such as meadowfoam (Limnanthes summer dry season. gate the wetland soil conditions. Finally, we douglasii ssp douglasii; Figure 1) and marsh inspected modern and historic aerial photos monkeyflower(Mimulus guttatus). Investigating Bouverie Preserve for evidence of wetland modification. Wetland 9 (Figure 3) is shallow, no wetlands deeper than our second group of wetlands, At the Bouverie Preserve we wanted to Hydrology the wet meadows (Figure 2). Yet after we know more about our wetlands, including We found two types of wetlands in the used prescribed fire in 2007 to minimize the how they may have changed over time. We Lower Field of the Bouverie Preserve. One growth of grasses in this area, the rare vernal knew there were some seasonal wetlands in the grassland that borders the highway, but we had no detailed information about the Table 1. Characteristic vernal pool species and generalist wetland species of the Bouverie Preserve, and the wetlands in which they are found. See Figure 3 for the locations of numbered wetlands. hydrology. We suspected that the wetlands were all vernal pools in various states of deg- radation. We hypothesized that the shallow- Wetland er wetlands may once have been deeper and 2 4 9 7 1 5A then suffered from silt accumulation caused Vernal pool species by management practices in a former era. The majority of vernal pools in Califor- water pygmyweed (Crassula aquatica) √ nia have been destroyed (Holland 1978), calicoflower(Downingia concolor) √ √ and the remaining ones are home to rare species. Because degraded vernal pools are dwarf downingia (Downingia pusilla) √ √ √ an area of great conservation concern, we coyote thistle (Eryngium aristulatum) √ √ were able to secure funding to investigate quillwort (Isoetes howellii) √ √ the nature of the wetlands of the Lower Field. The investigation involved four activi- popcorn flower(Plagiobothrys stipitatus) √ √ ties. First, we marked the deepest part of wolly marbles (Psilocarphus brevissimus) √ √ √ each wetland and then, during the rainy season, revisited that location each week to pacific foxtail(Alopecurus saccatus) √ measure water depth. Second, we conducted Generalist wetland species springtime vegetation surveys and used meadowfoam (Limnanthes douglasii) √ √ √ √ √ √ grazing, prescribed fire, and mowing to con- trol introduced European grasses in the dif- marsh monkeyflower(Mimulus guttatus) √ √ √ ferent portions of the Lower Field. Third, to iris-leaved rush (Juncus xiphioides) √ √ √ √ 2009 THE ARDEID page 3

role in draining the land. Gutters, ditches, and hard surfaces shunt winter rains quickly through 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 since 1823, Sonoma Valley has lost more than 95% of its freshwater wetland area (Dawson et al. 2008). Based on our field observations, the patterns evident on the aerial photograph, and documented historical trends in the wetlands of the Sonoma Creek watershed, we think that the main ways our wetlands have changed are in the reduction of their extent, the loss of hydrologic connectivity, and, possibly, a reduction in the number of days of inundation each year. They may have once been one small part of a large complex of wetlands in Sonoma Valley. The Bouv- erie Preserve provides a home for this relict habitat and its resident species, now rare in Sonoma County. For every answer suggested by an eco- Figure 3. Wetlands of Bouverie Preserve’s Lower Field and adjoining lands. Numbers indicate individual wetlands. logical mystery, new questions arise. Did our Highway 12 crosses from the upper left to lower right of the aerial photo. seasonally wet meadows previously remain wet for a greater part of the year? The wet pool specialist dwarf downingia was present. of War indicates this pattern was already meadows are currently dominated by intro- We did not introduce this species, so its evident in 1942. duced invasive species. What plant species presence in wetland 9 suggests that the seed previously dominated our wet meadows, bank of these wetlands is long-lived and can Putting together all the pieces and what animal species called them home? provide clues to the history of these sites. We found no evidence to suggest that the In general, wetlands provide important hydrology of the Bouverie wetlands has been ecosystem services, by filtering nutrients Soil investigations affected by silt accumulation. The hydro- and pollutants, providing flood control, and We found no evidence that the wetlands logical, biotic, and edaphic (soils) evidence sustaining natural environmental conditions were once deeper and have been filling revealed two distinct types of wetlands in that humans value. What ecosystem services in, though it is impossible to rule this out the Lower Field of the Bouverie Preserve. do our wet meadows provide? completely, based on the soil investigations. The wetlands with flashier hydrographs are In some wetland areas of the Lower Field, appropriately called vernal pools because of We are grateful to the US Fish and Wildlife including wetland 1, Dr. Steve Talley (2008) their characteristic vegetation and the likely Service Private Stewardship Grant Program, observed soil mottling, indicating a long presence of a clay hardpan associated with The Community Foundation of Sonoma history of wetting and drying (Figure 3). highly variable water depths (dashed lines County, and the Rockey Family Foundation During the course of excavating soil pits, he in Figure 2). In our system, these vernal for funding grassland restoration work at the discovered that wetlands 7 and 5a, which pools are primarily fed by overland flow of Bouverie Preserve. Conversations with soil have water levels that fluctuate less than the rainwater. The other type of wetland we have scientist Steve Talley informed this article. typical vernal pool’s, are fed by subsurface is wet meadow. Their hydrographs suggest seeps. He also found no mottling in the that our wet meadows are fed primarily by References cited swale that parallels the highway, suggesting the subsurface flow of ground water (solid Anonymous. c. 1837. Tereno Nombrado Guilucos Solicitado por Juan Wilson. Bancroft Library, University of Califor- this swale may not be natural and was cre- lines in Figure 2). nia, Berkeley. Map. ated as a byproduct of highway construction The basic sources of water for these two Boggs, W. 1861. Land Court Transcript, Los Guilucos Rancho. July 31. Bancroft Library, University of (Figure 3). types of wetlands, precipitation and subsur- California, Berkeley. face flow, have probably not changed over Dawson, A., M. Salomon, A. Whipple, and R. Grossinger. 2008. An introduction to the historical ecology of the Photographic investigations time, since they are dictated by the soil and Sonoma Creek watershed. Sonoma Ecology Center. Modern aerial photos of the area show subsurface water patterns. However, about Holland, R. F. 1978. The geographic and edaphic distribu- tion of vernal pools in the Great Central Valley, Califor- swales that end abruptly at roads and five years ago the preserve had to deepen nia. California Native Plant Society, Special Publication property boundaries. Other swales dead-end its well, so we know that there have been 4:1-12. Talley, S. 2008. Bouverie soils investigation. A report to after short stretches where they run exactly significant local changes to the ground Audubon Canyon Ranch. parallel to constructed features like the high- water level. What has happened to Altimira’s way and an apartment complex (Figure 3). “fountain of fountains?” Agricultural and An historic photo from the U.S. Department residential development has played a large page 4 THE ARDEID 2009

Strategic nest attendance by Great Egrets The Ecology of Parental Wisdom

by John P. Kelly and Christine A. Rothenbach

young unattended ity gives fledglings a valuable head start. But at the nest. We are how much time should parents devote to currently working to finding food vs. guarding their young? understand this para- The care of parents for their young is dox, by investigating common throughout nature, sometimes just how Great Egrets revealing impressive or even heroic efforts. (Ardea alba) nesting at What interests ecologists is that such care ACR’s Bolinas Lagoon is generally adaptive and often strategic. In Preserve schedule their birds, patterns of nest attendance are strong- nest attendance duties ly influenced by the developmental needs of to maximize their abil- their eggs and nestlings, by the challenges ity to fledge healthy of finding enough food to support a family, young (Rothenbach and by the complex and dynamic behaviors and Kelly, in prepara- of nest predators. A complete commitment tion). to any one of these concerns, however, can Midway through result in the neglect of other needs. So how the nesting cycle, do egrets determine the best way to manage herons and egrets shift family responsibilities? As in humans, the from “guardian” to best egret parenting is ad hoc and depends “post-guardian” nest on an ability to make wise decisions in attendance behavior. response to changing conditions. During the guardian period, parents share How parents make decisions incubation duties by To examine nest attendance choices, alternating their time we addressed two hypotheses based on at the nest so that, numerous observations of Great Egret nests together, they attend subject to the risk of predation by resident the nest continuously. Common Ravens (Corvus corax). First, we o

am After the eggs hatch, considered the “Trade-off Hypothesis”—that e K adults continue to egrets guard their nests continuously, to ann

jo take turns attending reduce predation risk, until increasing food When young egrets reach three to four weeks of age, parents must weigh compet- the nest and forag- demand of the developing nestlings forces ing challenges of guarding the nest against predators and gathering food from ing. When one parent both parents to forage for food simultane- surrounding wetlands. arrives at the nest with ously. This idea proposes that the increasing food for the nestlings, risk of nestling starvation forces parents to once watched a pair of ravens land next the other takes off to search for more food. leave their nests unguarded. To test this hy- Ito a Great Egret nest that was occupied When Great Egret nestlings reach three to pothesis, we evaluated how the age of chicks by two unguarded chicks. Immediately, the four weeks of age, both parents begin to for- at the onset of the post-guardian period ravens proceeded to harass the young birds. age for food simultaneously. This combined affects reproductive performance. After dodging several bill-thrusts from the feeding effort provides young with more Under the Trade-off Hypothesis, we defensive egret chicks, one of the ravens food but leaves them unguarded except predicted that egrets would guard their grabbed a nestling by its bill, pulled it down, during brief, frenzied feeding episodes. As nests as long as possible and that fewer nests and killed it. Although events like this seem nestlings grow, they become more defen- therefore would be taken by predators. We gruesome, they are not unusual in heron- sive and the likelihood of nest predation expected that the associated sacrifice of ries. Chicks guarded by adults are virtually declines, but younger, smaller nestlings can foraging time might reduce the number of immune to attack by ravens, but, surpris- be easily taken by predators. Presumably, chicks produced in successful nests, because ingly, herons and egrets typically leave their the intensified, post-guardian feeding activ- some of the young might starve. Among 2009 THE ARDEID page 5

to leave their nests Measuring parental behavior unguarded, to reduce The nesting performance of all breed- the per capita risk of ing pairs of egrets in the heronry has been predation by spread- monitored annually since 1967 (Pratt and ing risk across a larger Winkler 1985, Kelly et al 2007). For this pool of vulnerable study, we used nesting data from 19 years nests. Nestlings are (1984,1987–1997, and 2002–2008), exclud- more likely to be taken ing years when there was no observed nest by predators when predation or when the timing of the post- they are smaller, so the guardian period was not precisely measured. most dangerous time To focus on the parents’ competing of the season is when challenges of finding food for nestlings e n the developing young and protecting them from predators, we ree g are first left unat- included nests only if they met the follow- ng tended. To test Dilu- ing criteria: (1) at least one egg was hatched; ori l p i

l tion Hypothesis, we (2) nest failure, if it occurred, was caused by hi p counted the number predation; (3) the length of the guardian pe- As nesting egrets grow large, both parents work to meet the increased food de- of other post-guard- riod was precisely determined; and (4) the mand, returning to the nest only for frenzied feeding visits. ian nests in the colony nest was the first of the season at that nest on the day when each site and likely to have been the parents’ first nests that successfully avoid predation, how- nest was first left unattended. attempt that season (initiated before colony ever, those with shorter guardian periods Under the Dilution Hypothesis, we size began to decline). If an entire brood dis- should be able to raise more young. We also predicted that, in each successful nest, more appeared between observations, we assumed expected a narrow range of chick ages at the chicks would be fledged: if reduced per that it was taken by a predator. onset of the post-guardian period, because capita risk of nest predation allows parents To account for differences in parental parents might guard their nests until their to focus more time on foraging for food, behavior between successful and unsuc- young reach some critical age when food they may be able to support larger families. cessful nests, and among successful nests demand forces both parents to search for We also expected that greater synchrony in that fledged one, two, or three young, food. Finally, under the Trade-off Hypothe- leaving nestlings unattended might lead to we compared several statistical models sis, we expected relatively little synchrony in more nest failures, because any late broods, (explanations of egret behavior) based on the onset of post-guardian behavior in the with relatively small chicks, might be easily observations of nesting egrets. The models colony, because nests initiated at different taken by predators. Finally, under the Dilu- included controls to account for annual times should reach the critical nestling age tion Hypothesis, we expected a wider range differences in colony productivity, intra- at different times. of chick ages at the onset of the post-guard- seasonal timing, and environmental factors Second, we tested the “Dilution Hypoth- ian period, a necessary result of synchroniz- such as rainfall or temperature. The analysis esis”—that adult egrets in a colony synchro- ing parental behavior among nests initiated also distinguished egret parental behavior nize the time of the season when they begin at different times. between years with and without resident

Figure 1. Average percent of Great Egret nests that escape predation in relation Figure 2. Great Egret parents with successful nests (not taken by predators) are to the length of the nest guardian period (days after first hatch). likely to fledge more young if they reduce the length of the nest guardian period. page 6 THE ARDEID 2009

Figure 3. Great Egrets fledge more young, on average, if parents begin the post- Figure 4. Predicted number of Great Egrets fledged per nest attempt at Bolinas guardian period of nest attendance at a time when more nests in the colony are Lagoon, plotted against the length of the nest guardian period (at average unattended. values of other variables). Dashed line = ravens present; dotted line = ravens ab- sent; solid line = 50% chance of raven presence. Vertical reference lines indicate the predicted length of the guardian period.

ravens. We then examined the extent to extending the length of the guardian period, their young. This, in turn, would reduce the which the consequences of parental behav- which reduces available foraging time risk of nestling starvation and help parents ior explained by the models were consistent (Figure 4). Under simulated decreases in compensate for reduced wetland quality or with the predicted outcomes of the Dilution the presence of ravens, egrets reduced the quantity, including wetland losses related to and Trade-off hypotheses. length of the guardian period, increasing climate-induced sea level rise. foraging time. If conservation efforts can protect or Patterns of parental care improve heron and egret foraging oppor- Our results were consistent with the Conservation trade-offs tunities in surrounding wetlands and can predictions of the Trade-off Hypothesis. Successful parenting involves complex limit or reduce threats caused by introduced When egrets guarded their nests for a longer choices based on continual assessments or subsidized nest predators, then herons period of time, they decreased the chance of multiple concerns. The most successful and egrets might be able to sustain effec- of nest predation (Figure 1). However, Great Egret parents balance the costs and tive levels of reproduction through adaptive parents that successfully avoided nest benefits of guarding the nest continuously, parenting—in spite of dramatic changes to predation were likely to fledge more young leaving to gather food for their young, and the environment. Alternatively, the expected if they reduced the length of the guardian aligning the peak period of nest vulner- result of spiraling demands on egret parents period (Figure 2)—presumably because of ability with other nests in the colony. These is declining colony size or abandonment of increased time for foraging. We also found costs and benefits have potentially impor- the colony site. As in other areas of conser- support for the Dilution Hypothesis. Great tant implications for conservation. vation, the ecological implications of nesting Egrets fledged more young, on average, if Based on our results, restoring the behavior suggest benefits and concerns for they began the post-guardian period when quality or quantity of surrounding wetland the protection of heronries. more unattended (post-guardian) nests were feeding areas might not only allow nesting present in the colony (Figure 3). egrets to reduce their foraging range, spend References cited Egrets that made complex decisions to less time foraging, or increase the amount Kelly, J. P., K. Etienne, C. Strong, M. McCaustland, and M. L. Parkes. 2007. Status, trends, and implications for the optimize trade-offs in reproductive perfor- of food they bring back to their young—it conservation of heron and egret nesting colonies in the mance related to the combined risks of nest may also allow parents to increase the San Francisco Bay area. Waterbirds 30: 455-478. Pratt, H. M., and D. W. Winkler. 1985. Clutch size, timing of predation and nestling starvation—decisions length of the nest guardian period. This, in laying, and reproductive success in a colony of Great Blue influenced by the age of nestlings, energy turn, might allow them to compensate for Herons and Great Egrets. Auk 102: 49-63. demand, food supply, foraging opportuni- increases in predation pressure related to ties, and predation pressure—achieved the introduced nest predators or human subsi- highest reproductive success (Figure 4). dies of ravens or other predators. Similarly, How sensitive are nesting egrets to changes reducing the threats of introduced or subsi- in predation risk and opportunities for dized nest predators in heronries might al- foraging? Simulations based on our results low egret parents to reduce the length of the suggested that egrets are likely respond nest guardian period, increasing the amount to increases in the presence of ravens by of time they can spend gathering food for 2009 THE ARDEID page 7

A fine scale census of herons and egrets on Bolinas Lagoon Local Values

by Emiko Condeso

Figure 1. Bolinas Lagoon and vicinity.

n the afternoon light, the expanse of the heronry is intensively studied, we have characteristics of habitat. To address this IBolinas Lagoon is a mirror whose surface only just begun to examine how these birds question, and to augment a separate investi- is broken by exposed mudflats and rafts of utilize the lagoon itself. Because nesting her- gation of heron and egret foraging behavior, floating waterbirds. The water ranges from ons and egrets tend to restrict their foraging researchers at ACR conducted standardized shallow, to deep and salty, to brackish, pro- to wetlands close to their nest sites (Kelly censuses of Great Egrets, Great Blue Herons, viding a wide variety of habitats for wildlife. et al. 2008), Bolinas Lagoon is more than and Snowy Egrets on the lagoon. From More often than not, herons and egrets can simply a beautiful sight—it is critical habitat specified locations along the shore, they be seen in the shallows, foraging singly or in upon which the reproductive success of the used binoculars and telescopes to identify groups. During the breeding season, one of heronry depends. the species and locations of all wading birds the largest and longest-lived heron and egret Understanding the patterns of wading on the lagoon. Each one-hour census took nest sites in the Bay Area can be found on bird use of the Bolinas Lagoon will greatly place on a medium tide (2.5–3.5´ above the northeast shore of the lagoon at Picher enhance our ability to address local manage- mean lower low water). We noted whether Canyon, Audubon Canyon Ranch (Figure 1). ment concerns and also help to develop a observed birds were solitary or in groups, For more than 40 years, researchers at more general understanding of how herons whether they were in a foraging or non- ACR have monitored the Picher Canyon and egrets use the wetland landscape. Previ- foraging posture, what type of habitat they heronry, using a meticulous, twice-weekly ous work by PRBO Conservation Science were in (emergent vegetation, upland, mud- field protocol to obtain measures of colony shows that numbers of herons and egrets flat, etc.), and the depth of the water relative size and reproductive success. These and on the lagoon have fluctuated over time to the birds’ legs. The specific location of other data have contributed to the recog- (Shuford et al 1989). However, we do not each individual or group was recorded on nition of Bolinas Lagoon as a wetland of yet understand the extent to which heron an aerial photo. These data were then en- international importance by the Ramsar and egret abundance and distribution in tered into a Geographic Information System Convention (see Ardeid 2006). Although the lagoon varies in relation to fine-scale (GIS) for analysis. page 8 THE ARDEID 2009

Figure 2. Distribution of herons and egrets on Bolinas Lagoon in the non-breeding (triangles) and breeding (circles) seasons (August 2005 to February 2006 and March–July 2006, respectively). The sizes of symbols represent the number of individuals in a group of foraging birds (group diameter ≤ 100 m). This figure represents cumulative use of the lagoon by these species over one calendar year and does not represent the number of birds observed at any one point in time. 2009 THE ARDEID page 9

groups. Great Blue Herons were seldom found in groups, and they favored the Pine Gulch Creek delta, the area around , and the east shore of the lagoon near the channel (Figure 3). This is consistent with their solitary nature and a few studies suggesting that Great Blues tend to return to specific feeding areas (e.g., Dowd and Flake, 1985). During the non-breeding season, large groups of Snowy Egrets also concen- trated in areas of the lagoon where fresh water drains into the estuary, such as the mouth of Pine Gulch Creek. Individuals and small groups of Snowy Egrets were found in most of the shallower parts of the lagoon. During the breeding season, Snowy Egrets foraged in smaller groups or alone, though groups of 5–10 birds could still be found. Though extensive use of Bolinas Lagoon by herons and egrets is well known, un- derstanding and quantifying what makes habitat in this estuary preferable is actually quite difficult. The information presented here is part of a work in progress, and areas of the lagoon with relatively little observed use may still be very important to the birds at times when they were not observed. Precisely what is needed to support healthy populations of herons and egrets is a ques- tion often asked of conservation biologists, yet supportive data are usually lacking. ACR has begun to address this question for Bo- linas Lagoon, and it is our hope that future work will allow us to develop a more general understanding of these species’ habitat needs. Ultimately, such information may be important in evaluating and protecting Figure 3. Abundance (open symbols) of Great Egrets, Great Blue Herons, and Snowy Egrets on Bolinas Lagoon wetland quality wherever herons and egrets and the number of nests (filled symbols) of each species observed at the Picher Canyon heronry, Audubon Canyon occur. Ranch, by census date (August 2005–July 2006). References cited Great Egrets are a constant presence were observed on the lagoon at once (Figure Dowd, E. M. and L. D. Flake. 1985. Foraging habits and movements of nesting Great Blue Herons in a prairie river on the lagoon during the non-breeding 2). Snowy Egret use of the lagoon drops ecosystem, South Dakota. Journal of Field Ornithology 56(4):379-387. season, typically numbering less than ten off sharply after the onset of the breeding Kelly, J. P., K. Etienne, C. Strong, M. McCaustland, and M. individuals at any given time (Figure 2). season, when they are presumably tied to L. Parkes. 2006. Annotated atlas and implications for conservation of heron and egret nesting colonies in the During the breeding season, however, the foraging areas closer to their breeding sites San Francisco Bay area. ACR Technical Report 90-3-17, number of Great Egrets observed on the (Figure 2; Kelly, 2008). Audubon Canyon Ranch, P.O. Box 808, Marshall, CA 94940. 236 pp. lagoon increases dramatically. This increase During both the breeding and non- Kelly, J. P., Stralberg, D., Etienne, K., and M. McCaustland. is consistent with the number of active nests breeding seasons, all species tended to con- 2008. Landscape influence on the quality of heron and egret colony sites. Wetlands 28:257-275. at Picher Canyon. Great Blue Herons are not gregate at creek deltas and slough margins. Shuford, W. D., Page, G. W., Evens, J. G., and L. E. Stenzel. as abundant as either Great Egrets or Snowy Great Egrets are more widely distributed 1989. Seasonal abundance of waterbirds at : a Egrets on Bolinas Lagoon, nor do they nest throughout the lagoon than the other spe- coastal perspective. Western Birds 20:137-265. in great numbers at Picher Canyon (Figure cies observed, which may be related to their 2). Colonies of Great Blue Herons are typi- abundance and foraging behavior (Figure cally small throughout the Bay Area (Kelly 3). We recorded Great Egrets in the center of et al. 2006). Snowy Egrets have thus far been the lagoon and the area south of the mouth only occasional nesters at Picher Canyon; of Pine Gulch Creek (Figure 1), places however, they make great use of the lagoon both Great Blue Herons and Snowy Egrets during the non-breeding season. During our tended to avoid. During our study period, census periods as many as 60 Snowy Egrets Great Egrets foraged individually or in small page #10 THE ARDEID 20082009

How seed collection influences genetic diversity in ecological restoration Growing Diversity

by Hillary Sardiñas

umerous creeks carve the flanks of creating paths for gene flow in wind-pol- Reference sites and species selection NMount Tamalpais, in Marin County, linated species. However, this watershed In 2006, Audubon Canyon Ranch started as they snake toward the Pacific Ocean. model of gene flow does not hold true for work on the Four Canyons Restoration Proj- The area’s topography causes some of these all species. For example, fruits and berries ect—the restoration of former human-use streams to flow into San Francisco Bay and are consumed by birds and mammals that areas to wild habitat at BLP. Our restoration some directly into the Pacific Ocean, while are able to disperse seeds across watersheds sites are primarily located in canyon bot- others enter Bolinas Lagoon before reaching and regions. Because of the diversity of tomlands and riparian floodplains, which the sea. Although all of the creeks, including mechanisms for pollination and dispersal, have been affected by use as parking lots, those that carved the canyons of the Bolinas the concept of a “geneshed” is a useful way building areas, and storage sites for equip- Lagoon Preserve (BLP), are part of the to view the genetic range of a plant species. ment and materials used on the preserve. greater Mount Tamalpais watershed, they Unique for every species, a geneshed can These previous disturbances made the land form distinctive sub-watersheds that have be conceptualized as the area over which susceptible to invasion by weeds that com- different stewardship needs (Figure 1). a species’ genetic material can successfully pete with native plants for space, sunlight, Each of the four canyons that comprise travel. A coconut may be able to traverse the and nutrients. BLP is drained by a separate creek flowing entire Pacific Ocean, whereas a buckeye in To select our planting palette, we identi- into Bolinas Lagoon. The north- and south- Volunteer Canyon may only roll a few feet fied reference sites with similar character- facing slopes of each canyon host different from its source tree. ACR’s Habitat Protec- istics to our restoration site and used their species, due to numerous factors including tion and Restoration staff use the concept of species diversity to inform our project their exposure, slope, and soil type. The genesheds to think beyond sub-watersheds design (Figure 2). One of our goals is for our north-facing slope of Volunteer Canyon is when considering how far afield to roam sites to re-establish habitat capable of pro- dominated by coniferous forest, whereas when collecting seed for our restoration viding abundant resources to native insect, the canyon’s south-facing slope is mostly a projects. bird, amphibian and mammal species pres- mixture of oak woodland and ent at BLP. By including ground chaparral. Between canyons, cover, grasses, shrubs, and trees, these differences become even we can ensure that there will be more pronounced. For example, multiple layers of vegetation that the California sagebrush-domi- create a variety of habitats. Incor- nated south-facing slope in Gar- porating plants that set seeds or den Club Canyon is a dramatic produce berries enhances avail- contrast to the redwood forest able food resources for wildlife. just over the ridge in the north- Planting insect-pollinated plants facing Pike County Gulch. This provides valuable resources for varied topography is part of pollinators. Additionally, by us- what allows for the incredible ing plants that vary in the timing floristic diversity within the of their seasonal reproductive preserve. Yet it also provides a cycles, from early spring annuals challenge: which plant popula- to woody perennials that flower tions ought to be the source for in late autumn, our restoration plants used in ACR’s revegeta- sites will be able offer diverse tion efforts? resources throughout the year. Ecologists presume that, Once we have determined for most species, gene flow what species to grow for each generally follows the pathways site, seed collection can begin. Figure 1. The creeks that created the four canyons of the Bolinas Lagoon Preserve created by water, with seeds originate on the flanks of Mt. Tamalpais and terminate in the Bolinas Lagoon. They Most seeds do not mature until from upland populations carried are separated by steep ridges that isolate them from one another. For restoration mid-summer; they cannot be downstream by gravity or rain- purposes, we treat each canyon as its own distinct sub-watershed of Bolinas Lagoon planted in the same year they fall events. Additionally, winds and maintain its genetic integrity by using plants grown from seeds collected within are collected, because they need sweep up or down the canyons, the destination canyon. more time to grow to a stage 20082009 THE ARDEID page #11

where they have adequate resources to sur- discriminate against plants that do vive outplanting. In order to properly time a not appear to be as robust as other plant’s readiness, collection must occur one- individuals. Natural populations of and-a-half years prior to the planned project, plants consist of a mixture of indi- with seeds sown in pots during the spring viduals that vary in size, height, and preceding the winter planting season. Excep- so on, due to both genetic and envi- tions include annuals, early-maturing native ronmental effects. Therefore, the grasses, and seeds that are directly sown into appearance of a plant at a particular sites; these can be collected the spring before time or place may not be a good planting, or in the case of a late-bloom- measure of its genetic value. ing species, sown directly into sites as they The Law of Space and Time is mature in the late fall/early winter. a guideline that encourages seed collecting at several locations of Principles of seed collection the geneshed and at different times A major concern that conservation proj- throughout a species’ seed ripening ects confront is how to collect sufficient seed season. By following this practice, to achieve restoration goals without over- collectors have a better chance of harvesting from native plant populations. encountering early- and late-flower- To address this issue, native plant nurseries ing varieties. Because natural popu- have created the following three guidelines lations contain plants that bloom for seed collection (adapted from Young at different intervals, this measure 2007, Proposed Seed Collection Guidelines, helps ensure that a seed sample re-

Golden Gate National Recreation Area): flects the natural variability present Liu a

1. The Five Percent Rule: Collect no more in the wild population. By collecting dr an

than 5% of the available seed from any spe- from throughout a plant’s geneshed, ss a y C

cies in a specific area or from any particular we can increase the chances of b os

individual. encountering that species in differ- t ho 2. The Rule of Ten: Collect from as many ent environmental conditions and p plants of each species as possible throughout of capturing adaptations associated Figure 2. Restoration site (top) and associated reference site a collection area, and never from fewer than with such variation. (botom) in Garden Club Canyon. ten plants. All these measures help ensure 3. The Law of Space and Time: Collect that our seed inventory reflects the diversity enhance survival in certain conditions. By throughout the species’ geneshed; collect contained within wild populations, without crossing populations that have not tradi- several times throughout the seed ripening harming these populations. However, all tionally interbred, new alleles introduced period. these conditions beg the question: Why is from a different environment might result in The Five Percent Rule is based upon find- diversity important? traits that decrease a plant’s ability to survive ings by Menges and others at the Archbold or reproduce (Figure 3). Biological Station, Lake Placid, Florida, who Diversity sustains local adaptations By including seeds from different loca- stated that less intense, frequent harvests are Genetic variation is essential because it tions within a local population’s geneshed, safer than more intense, infrequent harvests. allows populations to adapt and evolve to seed collectors attempt to decrease the They found that high rates of seed removal changing conditions. If there is not suf- potential for inbreeding or outbreeding, (over 50%) significantly reduced population ficient genetic variation, populations may while optimizing localized genetic variation. growth rate and increased probabilities of be unable to withstand changing conditions Local adaptations are important, because extinction in some species. By collecting that limit their survival or reproduction, they may confer traits that could contribute only a small portion of the seeds available, potentially leading to extinction. Limited to the resilience of native plants in restora- we can help wild populations to persist, resources within a gene pool can lead to a tion sites. For example, “competitive traits,” prosper, and provide genetic material for condition known as inbreeding depression. such as early germination, may actually future projects. Additionally, at BLP we col- Inbreeding depression can make a popula- enhance growth during the seedling phase, lect seeds from populations over a series of tion vulnerable to deleterious recessive when competition with non-native species years, making sure that our efforts in a given alleles—gene forms that are normally hid- is typically most pronounced (Leger 2008; year do not cause major demographic shifts den or neutral in large populations but can Ecological Applications, 18:1226–1235). in native plant populations. produce dangerous traits in small popula- Because of the widespread abundance of The Rule of Ten ensures that particular tions if there is a strong likelihood of mating non-native and invasive species in coastal versions of genes (alleles) from only a few between genetically similar individuals California ecosystems, competitive traits plants do not dominate the population in (Figure 3). These traits may lower a plant’s could prove essential for the continued restored sites (Knapp and Rice 1994; Resto- ability to survive or reproduce and can cause survival of some plants. By collecting seeds ration and Management Notes 12:40–45). a small population to become extinct. directly from a site slated to be restored and Harvesting seed from a variety of different The opposite of inbreeding depression from other sites within a species’ geneshed, individuals helps to balance their genetic is outbreeding depression. Outbreeding we can ensure that localized adaptations are contributions to the population. It is for depression occurs when foreign traits dilute present. this reason that seed collectors try not to or overwhelm local traits that evolved to page #12 THE ARDEID 20082009

Climate change Toward balance Although there are numerous predic- Taking all of the aforementioned factors tions concerning the effects of climate into consideration is tricky, because we change, none of the models reliably describe do not want to risk incorporating native how global warming patterns will actually plants that are not capable of surviving in manifest. Collecting seeds from plants that our restoration sites, causing gaps that may inhabit the local extent of their geneshed allow invasive species to re-colonize. In (such as at different altitudes and aspects) order to prevent such a scenario, we moni- could help protect species from climate tor the survivorship of each plant species. change. For example, suppose a certain If particular species do not survive in a site, Figure 3. A represents a normal dominant version plant typically grows in shade but occa- we can replace them with different species. of a gene (allele), a represents a deleterious recessive sionally is found in sunny, exposed areas: allele, and A represents a dominant allele from a foreign The information we gather enables us to by using seed from individuals growing in population. Dominant alleles typically suppress recessive measure our progress and alter any methods sunnier areas, we might be able to enhance alleles, however inbreeding increases the probability that are not working. This flexible and com- the population’s likelihood of surviving a that recessive alleles will be expressed more frequently, prehensive approach favors the long-term climate shift toward drier conditions. Such which could harm the population. On the other hand, success of our restoration sites. crosses are risky, however, because they outbreeding could introduce alleles that could have Through thoughtful seed collection, beneficialor harmful effects, depending upon the might lead to outbreeding depression, so a careful project design that incorporates a evolutionary history of the original population. cautious approach may be critical. There- regard for genetic diversity, and a strategy fore, the three guidelines for seed collection for adaptively improving our work, the (above) should result in plants with varied early winters in a row could thwart the Habitat Protection and Restoration team at genetic stock that are capable of establishing maturation of seeds and prevent a rare plant Audubon Canyon Ranch is restoring the de- in the short-term and adapting to uncertain from replenishing its seed bank. If random, graded areas at the Bolinas Lagoon Preserve. future conditions. harmful events continue, the plant popula- Applying the principles of diversity to our Even if the effects of climate change tion could be threatened with extinction. By projects helps ensure that plant communi- are not significant, weather and rainfall maintaining genetic diversity within restora- ties we conserve are resilient, healthy, and can be extremely erratic. Random natural tion sites, we may promote the presence of capable of adapting to the multiplicity of events can have damaging effects on small, resilient individuals to insulate the popula- conditions the future may bring. susceptible populations. For example, two tion against unpredictable weather patterns.

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

Effects of invasive species on nitrogen retention Black Brant counts at , Tomales A camera trap survey of mammals and birds and other issues in the ecology and restoration Bay and Bodega Bay. Rod Hug, Santa Rosa, at Audubon Canyon Ranch, Rich Tenaza, of coastal prairie. Jeff Corbin,U nion College. California. University of the Pacific, and Chris Wemmer, Carbon addition and mowing as restoration Strophariaceae of California. Peter Werner, California Academy of Sciences. measures in a coastal California Grassland. Dennis Desjardin, San Francisco State Non-fire and non-soil controls of the chaparral/ Brody Sandel, UC Berkeley. University. grass boundary in California. Marc Coudel, UC Ecological indicators in West Coast estuaries. Effects of landscape context and recreational Davis. Steven Morgan, Susan Anderson, and use on carnivores in northern California. Sara Field verification of habitat connectivity models others, PacificE stuarine Ecosystem Indicator Reed, UC Berkeley. for the Mayacamas Mountains ecosystem. Research (PEEIR) Consortium [www-bml. Impact of an introduced plant pathogen on Justin Kitzes, Sarah Reed, and Adina ucdavis.edu/peeir]. Lyme disease ecology. Cheryl Briggs and Merenlender, UC Berkeley. Long-term monitoring of the Giacomini Andrew Swei, UC Berkeley. Initial Suyrvey of vegetation used for questing wetland. Lorraine Parsons, Point Reyes Impacts of Wild Turkey (Maleagris galpavo) on by Ixodes pacificus (Acri:I xodidae). Martin National Seashore. native avifauna in northern California. Angela Castro, California Department of Health Analysis of sedimentation in natural and Gillingham, Duke University/California State Services, Vector-borne Disease Section. restored marshes. Lorraine Parsons, Point Parks. Tidewater goby assessment and protection Reyes National Seashore. Effects of planktivorous fish predation on activities associated with the Giacomini Ranch Factors causing summer mortality in Pacific larvae release patterns of estuarine crabs. Leif Restoration Project. Darren Fong, Golden Gate oysters. Fred Griffin,U C Davis Bodega Marine Rasmuson, University of Puget Sound. National Recreation Areas. Lab. Investigtion of fossil Olivella (a marine snail) A comparison of carbon cycling and material from the Millerton Formation at Toms Point, exchange in grasslands dominated by native Tomales Bay. Daniel Muhs, U.S. Geological and exotic grasses in northern California. Laurie Survey. Koteen, UC Berkeley. 2008 the Ardeid page 13

In Progress: developing a comprehensive Four Canyons Project ª ACR’s methods to remove and monitor plan for long-term stewardship, Bolinas Lagoon Preserve contains the first known infestations in project updates including field surveys to assess four canyons that drain the Tomales Bay and, hopefully, biological values, cultural history, western slope of . prevent further invasion. Current projects by Audubon and management needs. The We are restoring the natural Saltmarsh Ice Plant Removal Canyon Ranch focus on the work is being made possible complexity of native vegetation ª We have eradicated non- stewardship of sanctuaries, through generous support in the lower reaches of these native ice plant from marshes ecological restoration, and provided by Jim and Shirley canyons, repairing disturbed sites, and upland edges at Toms issues in conservation science. Modini. The completed plan will and eradicating or controlling Point on Tomales Bay, although include implications for regional invasive plant species. Native management to remove conservation in the central plant propagation facilities in Picher Canyon Heron and resprouts and new patches Mayacamas Mountains (see Volunteer Canyon are being used Egret Project ªThe fates of continues. Native vegetation has photo on back cover). to grow locally collected plant all nesting attempts at ACR’s recruited into areas where ice materials for restoration. Picher Canyon heronry have Tomales Bay Waterbird plant was once dominant. been monitored annually Survey ªSince the winter of Monitoring and Control Eradication of Elytrigia since 1967, to track long-term 1989–90, teams of observers of Non-Native Crayfishª pontica ssp. pontica ªElytrigia variation in nesting behavior and have conducted winter waterbird Jeanne Wirka and others are is an invasive, non-native reproduction. censuses from survey boats on studying the distribution of perennial grass that forms dense Tomales Bay. The results provide non-native signal crayfish Tomales Bay Shorebird populations in seasonal wetlands. information on habitat values (Pacifastucus lenisculus) in Stuart Project ªSince 1989, we have At Bouverie Preserve, we are and conservation needs of more Creek at Bouverie Preserve and conducted annual shorebird eliminating a patch of Elytrigia than 50 species. We are currently investigating the use of barriers censuses on Tomales Bay. Each using manual removal, light investigating trends in species and traps to control the potential census involves six baywide starvation/solarization (black abundances and relationships impacts of crayfish on native winter counts and one baywide plastic tarps), and herbicide spot count each in August and April with Pacific herring roe as amphibians and other species. important food for wintering treatments of outlier patches. migration periods. A team of Highway-Generated Nitrogen waterbirds in Tomales Bay. Nest Boxes ªTony Gilbert 15–20 volunteer field observers is Deposition in Vernal Wetlands maintains Western Bluebird needed to conduct each count. North Bay Counties Heron ªEnhanced availability of nest boxes in the Cypress The data are used to investigate and Egret Project ª Annual nitrogen near highways might Grove grasslands. Rich Stallcup winter population patterns, local monitoring of reproductive facilitate invasion by non-native maintains several Wood Duck habitat values, and implications activities at all known heron plant species in sensitive vernal nest boxes along Bear Valley for shorebird conservation. and egret nesting colonies in wetlands. Dan Gluesenkamp, Creek in ACR’s Olema Marsh. five northern Bay Area counties Stuart Weiss, and Jeanne Wirka began in 1990. We are currently are quantifying the potential Restoration of Coastal Dunes investigating the effects of effects of highway-generated by Removal of Ammophila landscape habitat patterns on nitrogen deposition on Sonoma arenaria ªAmmophila arenaria nesting herons and egrets. ACR’s Valley vernal pools. is a highly invasive, non-native 250-page Annotated Atlas and plant that alters the topography Plant Species Inventory ª Implications for the Conservation and function of coastal dunes. Resident biologists maintain of Heron and Egret Nesting Removal of Ammophila at inventories of plant species Colonies in the San Francisco Bay Toms Point, on Tomales Bay, is known to occur on ACR’s Tomales Area includes an analysis of the helping to protect native species Bay properties and at Bouverie regional status and trends of that depend on mobile dune and Bolinas Lagoon preserves. herons and egrets and provides ecosystems. individual accounts of all known Annual Surveys and Removal Vernal Pool Restoration and heronries in the area (www. of Non-Native Spartina and Reintroduction of Imperiled egret.org/atlas.html). We have Hybrids ªIn collaboration with A Natural Resources Plants ªDan Gluesenkamp, also developed a reference that the San Francisco Estuary Invasive Management Plan for Modini Jeanne Wirka, and Sherry uses Google Earth to show the Spartina Project, Emiko Condeso Ingalls Ecological Preserve Adams are restoring habitat ª locations and status of northern and Gwen Heistand coordinate Audubon Canyon Ranch has conditions in the vernal pools at Bay Area heronries (www.egret. and conduct comprehensive field signed a collaborative, planned Bouverie Preserve. The project org/googleearth2.html). surveys for invasive, non-native giving agreement with Jim includes the removal of invasive Spartina in the shoreline marshes and Shirley Modini to acquire Impacts of Wild Turkeys on plants and re-establishment of Tomales Bay and Bolinas 1,725 acres in northern Sonoma Forest Ecosystems ª Dan of the federally listed Sonoma Lagoon. County. The property, to be Gluesenkamp is conducting a sunshine (Blennosperma known as the Modini Ingalls study to experimentally measure Monitoring and Eradication bakeri) and California species Ecological Preserve, has been in the effects of ground foraging by of Perennial Pepperweed in of conservation concern dwarf the Modini Ingalls family since invasive, non-native Wild Turkeys Tomales Bay ªInvasive, non- downingia (Downingia pusilla). 1867. This remote, undisturbed on vegetation and invertebrates native pepperweed (Lepidium The work involves manual effort landscape is a rich blend of in the forest ecosystem of latifolium) is known to quickly by volunteers, propagation and oak woodlands, pine forests, Bouverie Preserve. cover floodplains and estuarine planting of native plants, use of perennial grasslands, chaparral, wetlands, compete with native prescribed fire, cattle grazing, and serpentine outcrops, and species, and alter habitat monitoring of vegetation and wild streams. Sherry Adams is values. We are using a variety of hydrology. Ardeid (Ar-DEE-id), N., refers to the any member of the family Ardeidae, which includes herons, Ardeid egrets, and bitterns.

The Ardeid is published annually by Audubon Canyon Ranch as an offering to Conservation Science and Habitat Protection field 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 ACR’s 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

Conservation Science audubon Canyon Ranch—a system of wildlife sanctuaries and Habitat Protection and centers for nature education. at Audubon Canyon Ranch Bolinas Lagoon Preserve • Cypress Grove Research Center • Bouverie Preserve

Southward view across the Modini Ranch in the Mayacamas Mountains of northern Sonoma County. C R

Long-term stewardship plan see page 13 Wirka / A Jeanne

Audubon Canyon Ranch Non-profit 4900 Shoreline Highway Organization Stinson Beach, CA 94970 U.S. Postage PAID Cypress Grove Research Center MailCom P.O. Box 808 Marshall, CA 94940 (415) 663-8203