Wildlife and Terestrial Ecosystems Program

Fire Effects on Populations and Habitats of Sensitive Species of Wildlife in Ponderosa Pine Forests of the Interior West PRELIMINARY RESULTS *Joint Fire Final Report (# 01-1-3-25) Prescribed fire strategies to restore wildlife habitat in ponderosa pine forests of the Intermountain West *Nesting Birds *Vegetation *Point Counts

Nesting Birds

Both wildfire and prescribed fire are necessary for the long-term persistence of birds, which suggests that managers must strive to maintain a mosaic of conditions across the landscape. For example, white-headed woodpeckers and pygmy nuthatches favor habitat conditions created by understory fire; pileated woodpeckers favor forests with fire exclusion; Lewis's, three-toed, and black-backed woodpeckers are strongly associated with stand-replacing conditions; whereas hairy woodpeckers do not clearly favor one habitat condition

Download Preliminary Results - Vegetation and Bird Densities

OVERSTORY

Birds and Burns Prescribed Fire Vegetation Analysis (through 2002) -Overstory Summary

SNAGS & TREES

Birds and Burns Prescribed Fire Vegetation Analysis (through 2002) Snags & Trees BandB_snag_trees2005_May8.pdf

GROUNDCOVER and SHRUBS

Birds and Burns Prescribed Fire Vegetation Analysis (through 2002) Groundcover and Shrubs

LOGS and OTHER FUELS

Birds and Burns Prescribed Fire Vegetation Analysis (through 2002) Wildlife Logs & Downed Woody Fuels

SONGBIRD POINT COUNTS

Birds and Burns Pre-Treatment Estimates of Bird Densities

Birds and Burns Pre and Post Treatment Comparison of Bird Densities (Preliminary)

Preliminary Results - Bird Point Counts

Role of prescribed fire in maintaining breeding bird diversity in ponderosa pine forests of the western United States

this web page was adapted from a poster presented at the Ecological Society of America (90th Annual Meeting) and the IX International Congress of Ecology, 7-12 August 2005, Montreal, Quebec, Canada.

R.E. Russell^1,2,*, V.A. Saab², W.M. Block³, J.F.Lemkuhl⁴, S.Story¹, B.G. Dickson⁵, and S. Jentsch^6
1Montana State University, Bozeman, MT, ²USDA Forest Service, RMRS, Bozeman, MT, ³USDA Forest Service, RMRS, Flagstaff, AZ, ⁴USDA Forest Service, PNW, Wenatchee, WA, ⁵Colorado State University, Ft. Collins, CO, ⁶University of Arizona, Tucson AZ, ^*contact author for R code used in analysis (RRussell@mt.gov)

Introduction

Fire suppression, livestock grazing, logging and climate change have contributed to the increased likelihood of large and severe wildfires in ponderosa pine (Pinus ponderosa) forests of the Rocky Mountain region (Schoennagel et al. 2004).

The U.S. government passed the Healthy Forest Initiative in 2003 to reduce the risk of severe wildfire. A commonly used management practice to reduce forest fuel loads is low-severity prescribed burning. Little is known, however, regarding the role of prescribed burning in shaping forest bird communities.

The Birds and Burns network (http://www.rmrs.nau.edu/birdsandburns/) was developed to examine the effects of fire management practices on forest characteristics and wildlife populations (primarily birds) in ponderosa pine forests across the Interior Western United States (Figure 1).

Objective

One objective of the Birds and Burns network is to determine the effects of prescribed fire on songbird and squirrel densities in ponderosa pine forests and to determine if those effects differ by region, foraging guild, nesting guild, or nest type.

Study Design

Before-After-Control-Impact (Osenberg et al. 1994).

Data collection began at least 1 year prior to prescribed burning on each pair of control and treatment plots and will continue for a least 1 year after burning at eight locations across the Interior Western U.S.

2-3 pairs per location
1 pair=2 paired units each 250-400 ha

10-30 random point count stations per unit. Each station is a 100-m radius circular plot at least 250 m apart and 200 m from an edge.00

Point counts (Distance Sampling)

• May 22nd-July 3rd (2-4 visits per station)
• Dawn- 5 hours post dawn
• Observer stands in center of station and records all species heard or seen and distance from observer
• Observations are grouped into four distance categories (0-10 m, >10-25 m, >25-50 m, >50-75 m, and 75-100 m)

Prescribed Burning

• Burn Treatments were implemented in the Fall 2003 and Spring 2004 at units in the SW region, 1 unit in Idaho, and 2 units in Washington.
• Only prescribe burned units were used in the following analysis and data were collected within one year of fire.

Statistical Analysis

Density Estimation:

Program Distance (Thomas et al. 2005). Density estimates were generated using treatment (burned/not burned) as a covariate in the detection function for each species.

Detection functions and density estimates were obtained separately for the NW and the SW regions.

Density estimates were obtained for each unit (2 units per pair) pre- and post- burn.

Bootstrapping. Small sample sizes and a lack of independence between density estimates made bootstrapping necessary. Units were resampled with replacement 1000 times to obtain density estimates for each plot.

Figure 1. Study locations for the Birds and Burns Network.

Differences in population densities attributable to burn = After treatment (treatment density - control density) - Before treatment (treatment density - control density) averaged across all units in a region and across all resampled data sets (empirical 95% C.I. calculated from frequency distribution of the bootstrapped samples). That is, population density differences are calculated by taking density differences between treatments and controls before burning and comparing to the differences between treatments and controls after burning.

The following eight bird and squirrel species were selected for analysis.

Common name	Scientific name	Region	Foraging guild	Nest Layer	Nest type
Hairy Woodpecker	Picoides villosus	NW,SW	wood	canopy	cavity
Chipping Sparrow	Spizella passerina	NW,SW	omnivore	ground/shrub	open
Dark-eyed Junco	Junco hyemalis	NW,SW	omnivore	ground	open
Mountain Chickadee	Poecile gambeli	NW,SW	foliage	canopy	cavity
Western Tanager	Piranga ludoviciana	NW,SW	foliage	canopy	open
Western Bluebird	Sialia mexicana	SW	aerial	canopy	cavity
Pygmy Nuthatch	Sitta pygmaea	SW	omnivore/wood	canopy	cavity
Townsend's Solitare	Myadestes townsendi	NW	aerial	ground/shrub	open
Red Squirrel/Douglas Squirrel	Tamiasciurus hudsonicus/douglasii	NW	predator/omnivore	canopy	open

Expectations (based on Saab and Powell 2005)

Squirrels: decline immediately postfire due to direct mortality and rebound over time.
Omnivores: neutral response.
Foliage gleaner: decline due to leaf biomass reductions.
Aerial insectivores: increase due to more open canopy and increased insect abundance.
Ground nesters: decline immediately postfire due to lack of ground cover, increase quickly after fire with regrowth of ground vegetation.
Shrub nesters: decline immediately postfire due to lack of ground cover, increase more slowly after fire with regrowth of taller shrubs.
Canopy/cavity nesters: increase postfire due to the increased availability of dead/dying trees & associated insects.
Canopy/open nesters: increase due to lower predation rates.

Results

Figure 2. Change in songbird densities attributable to prescribed burning in Northwest and Southwest ponderosa pine forests. Diamonds denote average of 1000 bootstrapped data sets. Lines represent the empirical upper and lower confidence limits as derived from the frequency distribution. *Indicates 95% C.I. that does not include zero.

Discussion

Responses to prescribed fire within 1 year of treatment

Regional

No obvious differences observed in regional responses of a species to prescribed burning. Trends for species observed in both regions were only significant for Hairy Woodpeckers in the SW and Western Tanagers in the NW.

Squirrels

Exhibited no clear response to prescribed burning. Low severity burning probably prevented mortality.

Foraging guild

Omnivore: Chipping Sparrow and Dark-eyed Junco showed no clear response, while Pygmy Nuthatch populations declined after burning.
Foliage Gleaners: Western Tanager generally responded positively, however, this difference was significant only in the NW. Mountain Chickadee populations showed no clear response.
Aerial insectivores: Western bluebirds exhibited positive responses as expected, while Townsend’s Solitaire exhibited negative responses.

Nest Layer

Ground: Chipping Sparrow and Dark-Eyed Junco showed no statistically significant responses, although a positive trend was observed.
Shrub: Townsend’s Solitaire declined as expected.
Canopy/Cavity: Hairy Woodpecker and Western Bluebird responded positively as expected; however, Pygmy Nuthatches declined postfire and Mountain Chickadees showed no response.
Canopy/Open: Western Tanager responded positively in the NW & Chipping Sparrow showed no response.

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Acknowledgements: Funding is provided primarily by the National fire Plan (02.RMS.C.2), Joint Fire Sciences Program (01-1-3-25), and Rocky Mountain Research Station (4251). Matching funds provided by participating National Forests. Primary collaborators are Pacific Northwest Research Station, the Nature Conservancy, and Montana State University. Site managers are Craig Beinz and Amy Markus (Oregon), Lisa Bate (Montana), Kent Woodruff (Washington), Gary Vos (Colorado). We thank Len Thomas for assistance with statistical analysis and developing R code along with Tiago Marques, and Ingrid.

Citations:
Osenberg, C.W., R. J. Schmitt, S. J. Holbrook, K. E. Abu-Saba, and A. R. Flegel. 1994. Detection of environmental impacts: natural variability, effect size, and power analysis. Ecological Applications 4:16-30.
Saab, V., and H. Powell. 2005. Fire and avian ecology in North America: process influencing pattern. Studies in Avian Biology 30: 1-13.
Schoennagel, T., T. T. Veblen, and W. H. Romme. 2004. The interaction of fire, fuels, and climate across Rocky Mountain forests. BioScience 54:661–676.
Thomas, L., Laake, J.L., Strindberg, S., Marques, F.F.C., Buckland, S.T., Borchers, D.L., Anderson, D.R., Burnham, K.P., Hedley, S.L., Pollard, J.H., Bishop, J.R.B. and Marques, T.A. 2005. Distance 5.0. Release (Beta 3). Research Unit for Wildlife Population Assessment, University of St. Andrews, UK. http://www.ruwpa.st-and.ac.uk/distance/

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