Pine-grassland Birds and the Effects of Fire

Frequency, Seasonality, and Scale

Jim Cox

Tall Timbers Research Station

Pine-grassland forests in Florida support more species

of breeding birds per acre than hardwood-dominated

forests

Frequency

Season

Scale

Frequency

Season

Scale

Water oak, sweetgum, pine

1966

1981

2001

Loblolly-shortleaf

NB-66Fire suppression for 40 years

Bird Counts on NB66: 1966-1983

1960 1970 1980 1990 2000 2010YEAR

20

25

30

35

40

SPEC

IES

RIC

HN

ESS

Breeding birds on NB66 (1965-2010)

1966

1981

Fire Frequency and Bachman’s Sparrow

Trend -2.3%

43 nests in areas burned <10 months

4 nests in areas burned >18 months

Nest Site Selection

-4 0 4 8 12 16 20 24Months Since Burn

0

5

10

15

Perc

ent B

a re

G ro u

nd

Bar

e G

roun

dB

are

Gro

un

d %

Changes in % bare ground with time since burn

-4 0 4 8 12 16 20 24Months Since Burn

0

5

10

15

Perc

ent B

a re

G ro u

nd

Nests

Bar

e G

rou

nd

%

Changes in % bare ground with time since burn

6 Months Post-burn 18 Months Post-burn

Burn frequencies optimal for some species may seem extreme

Florida BBS trend: -5.45% per yearEastern Meadowlark

1985 1990 1995 2000 2005YEAR

0

1

2

3

4

5

6

7

EAM

L Te

r rito

ri es

Meadowlark Trends on Wade Tract

RED-COCKADED WOODPECKER

Cavities excavated only in living pine trees

Requires large areas of mature (>90 yrs) pine forests (BA 40-80+)

Requires frequent (≤ 3 year) burning.

Greater diversity of

arboreal ants on sites burned

≤3 year

Red-cockaded Woodpecker

n

Average percent decrease in woody/palmetto per 10 years

1. Dormant season burn every three years

19 -2

2. Growing season burn every other year

18 -17

3. Both dormant and growing season burns

17 -24

Higher frequency burning puts more calcium into food cycle.

Larger clutches laid in first year after a fire regardless of season.

Higher Frequency Improves Nest Productivity

Henslow’s Sparrow

Global Population <95,000

Winters throughout southeastern pinelands (Oct – Apr)

Florida Grasshopper Sparrow and Migratory Grasshopper Sparrow

FGSP GRSP HESP BACS0

10

20

30

40

50

60

70

Wet-mesic prairie

Burn 1

Burn 2

Burn 3

Burn 4

No.

indi

vidu

als

flus

hed

FGSP GRSP HESP BACS0

10

20

30

40

50

60

70

Dry-mesic prairie

Burn 1

Burn 2

Burn 3

Burn 4

No.

indi

vidu

als

flus

hed

Burn class = number of growing seasons post-burn

M. Korosy , UCF dissertation

Frequency:

<3 year return intervals best meet needs of declining

pine-grassland birds

Frequency

Season

Scale

Summer Burns Help to Control Thickets on Apalachicola National Forest

Thickets 1992

Thickets 2008

-4 0 4 8 12 16 20 24Months Since Burn

0

5

10

15

Perc

ent B

a re

G ro u

nd

Nests

Bar

e G

rou

nd

%

Two-year return interval

12 ha study area

70 ha burn block burned 5/28/2003

Return of Breeding Birds Following a Late May Burn

4 surveys prior to burn

9 surveys conducted after burn (1 visit every 5-7 days )

Least Squares Means

Pre Wk13 Wk46 Wk6pTIME

0

2

4

6

8

10AD

JABU

ND

Pre Week1-3 Week4-6 Week6+

Ab

un

dan

ce

Northern Bobwhite

Effect Coefficient Std ErrorCONSTANT 0.400 1.418 REG 1.368 0.638

ANOVA Source SS df MS F-ratio PRegression 35.4 1 35.4 3.3 0.06Residual 118.8 11 10.8

Winter Bachman’s Sparrow Abundance

Wade Tract Wade Tract

Burns

1 Year Interval 2 Year Interval

3 Year Interval 40 Years No Fire

Tall Timbers Fire Plots Established in 1958Can Early Season Burns Get the Job Done?

Productivity 1 yr post-fire

Fire Interval (yr)

Live

Abo

ve-g

roun

d B

iom

ass

(ton

ne/h

a)

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1 2 3 40

hardwood resproutsherbs

…where nearly everyone nests on the ground

Nesting season

Effects of burn season on breeding birds may be different…

Winter burns

Growing season burns

Don’t rush to mimic Mother Nature

Frequency

Season

Scale

“…burn at the smallest scalepossible to improve bobwhite survival and productivity.”

Wellendorf and Palmer 2006

Autumn Bobwhite Densities on Large- & Small-scale Burn Plots

25 acre 50 acre

100 acreGrowing season

Dormant season

Quail Productivity

Quail Abundance

Burn Scale and Bachman’s Sparrow

Summary

Male home range size

Male site fidelity

Maximum displacement

Monthly survival rates

Male densities

Tendency

Statistically significant

Larger on small-scale

Lower on small-scale

Greater on small-scale

No difference

Lower on small-scale

“Because of concerns about potential scale effects, it took us 5 days to burn the acreage we’d normally burn in a day…..”

Chuck Hess, ANF

Frequency

Season

Scale

Frequency

Season

Scale

Higher Importance

Lower Importance

Lack of fire is the disturbance!

0 1 2 3 4 5 6Maximum Burns

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

Occu

rre

nc e

Pro

ba

bili

ty

Burns conducted since 2001

Bachman’s Sparrows on Carolina Sandhill National Wildlife Refuge