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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