Summary of Implementation and Findings for the Green Diamond NSO HCP Since 1992
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Transcript of Summary of Implementation and Findings for the Green Diamond NSO HCP Since 1992
Summary of Implementation and Findings for the Green Diamond
NSO HCP Since 1992
1. Program 2. Status of Surveys 3. Demographic/Density Studies4. Data Available5. Summary of Trends
Signed September 1992
30-year plan with a 10-year major review (amended 2007)
Major Provisions of HCP
• Conservation strategy:– Grow owl habitat– Additional measures:
• Set asides– 39 areas, 13,200 acres (no harvest)
• Special management area– 36,500 acres, no owl “take”
• No direct harm to nesting owls• Research and monitoring• Incidental take permit (58 takes
over 30 years)
Studies and Monitoring
On-going surveys since 1989 and demography study since 1990
Numerous studies on prey base
Largest NSO dataset in existence: 1,824 captures, >4,000 total captures/recaptures
Dusky-footed woodrat
Sonoma tree vole
Residual older structure is important for roosting and nesting
Key NSO Findings
Woodrats are the primary prey and their
density is highest in young forest stands
Den
sity
(#
rats
/ h
a)
Stand age class
Food Habits
Hamm 1995
Telemetry study including night vision work,1998-2000
hunting perches
Development of “Foraging” and Nesting Resource Selection Models
• “Foraging” model based on telemetry data from 24 owls (1998-2000)
• Nesting model based on nests from 1990-2001
– Successful nest (173) with >75% coverage in GIS
– Foraging RS model applicable
Analysis of ‘Habitat Fitness’
• NTA (“Foraging”) model based on telemetry data
• Nesting model based on successful nests from 1990-2001
• Survival analysis– Mark-resight data of 835 individuals
from 1990-03• Fecundity analysis
– 467 nests from 1990-2001
Landscape habitat characteristics within 0.71 km radius circles. Dark areas are NSO habitat; white areas are other vegetation types.
(From Franklin et al., 2000)
Culmination of Ten-Year Review Analysis of Habitat Quality
• The very best habitat will increase by 83% over the life of the Plan
• By 2060, a total of 87% of the ownership is projected to be in the two highest categories of habitat quality
• Roosting and nesting habitat (stable core area) in close proximity to young forests (woodrat habitat) is the key
Fish bearing
Non-Fish bearing (2,531 miles)
Non-Fish bearing
Drivers of future habitat quality:Riparian reserves that will create more older forests adjacent to young forests
(Best)
Projections of Habitat Fitness
Future landscapes:•1st decade based on harvest forecast•Next 40 years based on spatially explicit harvest schedule model
Projections of Habitat Fitness
Future landscapes:•1st 10 years based on planned harvest schedule•Next 40 years based on spatially explicit harvest schedule model
Projections of Habitat Fitness
Future landscapes:•1st 10 years based on planned harvest schedule•Next 40 years based on spatially explicit harvest schedule model
Projections of Habitat Fitness
Future landscapes:•1st 10 years based on planned harvest schedule•Next 40 years based on spatially explicit harvest schedule model
Projections of Habitat Fitness
Future landscapes:•1st 10 years based on planned harvest schedule•Next 40 years based on spatially explicit harvest schedule model
Projections of Habitat Fitness
Future landscapes:•1st 10 years based on planned harvest schedule•Next 40 years based on spatially explicit harvest schedule model
0.0
10.0
20.0
30.0
40.0
50.0
60.0
70.0
YR2010 YR2020 YR2030 YR2040 YR2050 YR2060
YEAR
% O
wn
ersh
ip in
Cat
ego
ry
<0.88
0.88-0.94
0.94-0.98
0.98-1.05
>1.05
Percent Ownership in Different Projected Habitat Lambda Values by Decade
Trends in Apparent SurvivalFrom: Forsman et al. In press. “Demographic Trends of Northern Spotted Owls: A Meta-analysis, 1985-2008.
Trends in FecundityFrom: Forsman et al. In press. “Demographic Trends of Northern Spotted Owls: A Meta-analysis, 1985-2008.
Realized Rate of Population ChangeFrom: Forsman et al. In press. “Demographic Trends of Northern Spotted Owls: A Meta-analysis, 1985-2008.
Response of NSO to Habitat Modification
(Displacement)• Timber harvesting activities may directly harm
or kill owls – not documented in 20+ years• Some habitat modification may indirectly
harm owls through changes in behavior that results in a reduction in site occupancy, survival or reproduction – form of take documented under HCP
Reporting and assessment of take
occurred when habitat triggers exceeded
Direct – harvest within 500’ of owl site
Indirect – harvesting within 0.5 mile radius such that:
<89 acres >45 years old
or
<233 acres >30 years old
Biological Verification of Take
• Assess three years following timber harvest that triggered a take:– Owls nest in 2 years– Continuous occupancy and nesting in 1 year
• Assess for a maximum of five years following timber harvest
Analysis of Biological Impacts of Take
• Used top models from 2008 NSO meta-analysis (Forsman et al. 2011) to analyze impacts of take on survival and fecundity
• Conclusions:– Take as documented in HCP had no
measureable affect on mean annual survival– Take did affect reproduction with a mean annual
reduction of 2.8% in the number of young produced
Enter a New Threat
Northern Spotted Owl (Strix occidentalis caurina)
Northern Barred Owl (Strix varia varia)
Barred Owl Removal Experiment
• Beginning in 2009, barred owls removed (treatment) from half of Green Diamonds spotted owl study area
• Allowed to colonize and increase in the other half (control)
Response variables: NSO occupancy, survival and fecundity
Trend in occupied NSO sites on adjacent treatment and control areas
16 BOs removed from 9 territories
8 BOs removed from 5 territories
“Reference year”
11 BOs removed from 6 territories
Mad River NSO Sites
Sullivan
4107
41284230 #2
Nursery
4230 #1
Lower Quarry
Boundary
Lower Dry
5700
4076
6007
Blue Blossom
Devils Creek
4910
Lower Simpson
6000 CFDry Cr
Occupied in 2009
New in 2010
Scale = 0.5 miles
or = nested
Tentative Conclusions from Removal Case Studies
• At least some resident NSOs apparently remain near their historical activity center for years following displacement by BOs
• High and often rapid re-colonization by both original resident and new NSOs suggests BOs tend to displace NSOs from high quality sites (i.e., BOs are taking sites that are in “high demand” by NSOs)
Model averaged estimates of detection probabilities with 95% confidence limits derived from Green Diamond’s THP
data. Estimates were generated for May 7 of each year.
Date Julian date Survey1-Mar 61 18-Mar 68 2
15-Mar 75 322-Mar 82 429-Mar 89 5
5-Apr 96 6
Detection Probability (P) = 0.947
Rob Nagel Photography
Rob Nagel Photography
Forest HCP Covered Species
Northern Spotted Owl
Pacific fisher
Red and Sonoma tree voles
Courtesy Nick Nichols
Courtesy Nick Nichols
Conservation Program Biological GoalsRetain and Recruit Habitat Elements
Barred Owl Research
Promote Habitat Mosaic
Protection of Covered Species
Compliance, Validation, Monitoring, Adaptation
Photo courtesy Nick Nichols, NGM