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RESTORING VERNAL POOLS IN THESAN FRANCISCO BAY REGION

Michael Josselyn, PhD PWS

Lessons from long-term monitoring: 1997-2010

WRA, Inc, San Rafael, CA

VERNAL POOLS

• Seasonally ponded habitats that support a succession of aquatic plants and wildlife that are uniquely adapted to q y pbrief periods of ponding and/or soil saturation

• Common in Mediterranean climates; but also found in eastern states

California vernal pool distribution

Vernal Pool Tadpole ShrimpCalifornia Tiger Salamander

Contra Costa goldfields Burrowing Owl

alkali milk-vetchSan Joaquin spearscale

prostrate navarretia Congdon’s tarplant

Hoover’s button celery

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Site History—Long Term Disturbance

Pre-Project Site Conditions

Pre-Project Site Conditions

Limited Evidence of Past Conditions

1953

1985

Jurisdictional Wetlands--1995

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Vernal Pool Tadpole Shrimp

Contra Costa Goldfields

Corps Permit

• 46 acres of fill• 444 acre Preserve

– 59 ac existing wetland– 77 ac created wetland

• Create habitat for:– Vernal pool tadpole shrimp– Contra Costa gold fields– California tiger salamander– Burrowing owl

• Performance standards relative to reference sites

Vernal pool ecosystem restoration

• Understanding regional conditions• Investigation of site history and soil

conditionsconditions• Establishment of natural geomorphic variation• Creating habitat elements• Patience

Conceptual to Detailed Plan

• Excavate soil pits• Establish water budgets—

15% coverage– Seasonal wetlands– Vernal pools– VPTS/CTS pools

• Pool gradient and linkages• Avoid existing wetlands• Soil management to

reduce off haul

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Construction

Pacific Commons Preserve

Long Term Monitoring

• 10 year program• Hydrology• Vegetationg• Wildlife

– VPTS– CTS– Burrowing owls

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Wetland Hydrology Monitoring

Rainfall—Deviation from 12.8 in normal annual rainfall

• VPTS Habitat: Standing water greater than 0.20 feet deep for at least 60 consecutive days for years when the total rainfall is at least 75 percent of normal.

Hydrologic Classification

• Vernal Pools: Mean period of inundation does not deviate outside of the range of means of the reference vernal pools over the same period.

• Seasonal Wetlands: Mean number of consecutive days over which the upper 0.5 feet of soil is saturated or inundated exceeds 30 days.

Reference Pools

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Acres meeting hydrology criteria2005

3035404550

05

1015202530

Acr

es

VPTS Vernal Pool Seasonalwetland

Successful Wetland Area (acres) by Hydrologic Classification

Wetland Type Preserve Stevenson Total

VPTS Pools 45.64 8.72 54.36

Vernal Pool 41.34 0.10 41.44

Seasonal Wetlands 2.53 0.00 2.53

Totals = 89.51 8.82 98.33

Vegetation Monitoring

• Vernal pools– Similarity to reference in number, cover,

and species (5 criteria)• VPTS habitat

– Cover less than 30 percent (2 criteria)• Seasonal wetlands

– Dominance and cover by hydrophytes (5 criteria)

Vernal Pool Criteria

1. Dominated by native vernal pool spp.2. Number ssp = 80% of average ref

sppspp.3. Total cover > 50% avg cover ref pools4. % cover of native = % cover ref pools5. Total cover does not decline over time

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VPTS Criterion was not correct—VPTS only weakly associated with vegetative cover. Less than 60% cover was generally preferred

Seasonal wetlands

• Dominated by hydrophytic veg• # wetland ssp > 80% avg ssp in ref

poolspools• Wetland ssp cover > 50% avg ref pool• Percent native cover = ref native cover• Total cover showing no significant

declines

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Rare Plants Established

L th i jNavarretia prostrata Lasthenia conjugens

Astragalus tener v tenerDownwingia pulchella

Rare Plant Survey Annual Monitoring

Contra Costa goldfields (Lasthenia conjugens): Federal Endangered, List 1B alkali milk-vetch (Astragalus tener var. tener): CNPS List 1BSan Joaquin spearscale (Atriplex joaquiniana): CNPS List 1B

prostrate navarretia (Navarretia prostrata): CNPS List 1BCongdon’s tarplant (Centromadia parryi ssp. congdonii): CNPS List 1B

Hoover’s button celery (Eryngium aristulatum ssp. hooveri): CNPS List 1B

Contra Costa Goldfields Population Counts 1999-2010

19402400 2646 2705

2177

53534893

1485

7234

38843550

3000

4000

5000

6000

7000

8000

ed P

opul

atio

n Si

ze Observed Contra Costa Goldfields

135

1485

0

1000

2000

98-99

99-00

00-01

01-02

02-03

03-04

04-05

05-06

06-07

07-08

08-09

09-10

Monitoring Year (September-August)

Obs

erve

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Observed Alkali Milk-Vetch Individuals in the Preserve Areas1999-2010

264244

182 179149

150

200

250

300

pula

tion

Siz

e

Observed Alkali Milk-Vetch

35

3

49

8 0

117

65

0

50

100

150

98-9999-00

00-0101-02

02-0303-04

04-0505-06

06-0707-08

08-0909-10

Monitoring Year (September-August)

Obs

erve

d Po

p

Vernal Pool Tadpole ShrimpMonitoring

Photo: David Munn

2010 Monitoring Results for Egg-carrying (Gravid) VPTS Females

• Number of days to gravid detection via weekly sampling (max. values), beginning with dry pool :• Minimum: 37

Photo: Bill Stagnaro

• Minimum: 37• Average: 46 (± 8 SD)

• Literature: 41 days of inundation minimum; average 54 (Helm 1998)

60

80

100

t

Phase IPhase II

Percent of sampled pools containing VPTS by Phase, 2003-2010.

0

20

40

2003 2004 2005 2006 2007 2008 2009 2010

Perc

ent Phase II

Phase IIIPhase IVReference

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Summary of VPTS Occurrences at Pacific Commons, 1999-2010

Burrowing Owl

CTS Monitoring

Photo by Rhonda

15

20

25

30

35

s m

onito

red

# with CTS# without CTS

CTS Breeding Presence within Preserve, 2003 - 2010

0

5

10

15

2003 2004 2005 2006 2007 2008 2009 2010

# po

ol

+ - + + - -+ Above-average precipitation; - Below-average precipitation

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Summary of CTS Monitoring 2003-2010Long term management

• Weed management• Grazing managementg g• Feral animal control• Public access control

Grazing Management

• Reduce thatch and canopy cover of invasive grasses

• Increase pool hydro-• Increase pool hydroperiod

• Reduce reproductive success of invasive weeds

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Estimated grazing carrying capacity for the Refuge (WS) and Pacific Commons Preserves (PCP)

with a target residual dry matter of 800lbs/acre

PastureForage Production Y

WS 1

WS 2

PCP 3

PCP 4

PCP 5

PCP 6

PCP 7

PCP 8

PCP 9

Year

Average 19 19 8 3 8 6 9 3 3

Favorable 30 30 13 5 14 11 16 4 4

Total Estimated grazing carrying capacity (AU/Year) for an Average Year

78

Total Estimated grazing carrying capacity (AU/Year) for a Favorable Year

127

Grazing increases native species cover in uplands

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Years of Grazing and IntensityGrazing Lessons Learned

• Recognizing the effects of grazing in wetlands is difficult due to the stronger effects of rainfall, temperature, and ground water variation.

• It appears that wet season grazing provides the greatest benefit to wetland species.

• Still learning how to juggle plant needs,rancher needs, cow needs, and weather patterns.

PACIFIC COMMONS PRESERVECUSHING PARKWAY OVERCROSSING

The greatest danger for most of us is notthat our aim is too high and we miss it, but

that it is too low and we reach it." - Michelangelo