Pine-grassland Birds and the Effects of Fire Frequency, Seasonality, and Scale Jim Cox Tall Timbers...
-
Upload
mauricio-dain -
Category
Documents
-
view
214 -
download
0
Transcript of Pine-grassland Birds and the Effects of Fire Frequency, Seasonality, and Scale Jim Cox Tall Timbers...
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