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