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John A. Litvaitis - Case Study From Our Neighbors in the Eastern U.S.
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Do natural disturbance
regimes provide realistic guidelines for
managing early-successional
habitats in New England
forests?
Major forest types in northern U.S.
Lull (1968)
~1880
~1930
>50% of forest vertebrates utilizeearly-successional stands
Obligate users
RELA
TIV
E
US
E
0
1.0
10 20 30 40 50 60 70 80 90 100
AGE OF STAND
0.5
Golden-wingedwarbler
USGS
FOREST CLEARING
FARMABANDONMENT
FORESTMATURATION
Rela
tive a
bu
nd
an
ce o
fearl
y-s
ucc
ess
ion
al h
ab
itats
RETURN TO PRE-COLUMBIAN CONDITIONS ?
How much was there?
source: Harvard Forest
Methods to Estimate Natural Disturbance Regimes
Lorimer and White (2003)
• Sedimentary pollen and charcoal• Presettlement land surveys• Descriptions by early naturalists• Reconstruction of disturbance history in
old-growth stands• Modern records and aerial photos• Computer models
Large-scale fires infrequent in New England, ~800-1,200 years 1790 survey in NY found that 1% of landscape burned or open.
Small-scale wind storms: kill one to several trees. In eastern U. S., 0.2- 2%/year of all forests are affected by wind throw. At any time, 5-50% of a forest may be affected.
Large-scale wind storms: hurricanes or tornadoes at irregular intervals (1635, 1788, 1815, 1938, and 1944).
1938 hurricane affected >240,000 ha
in New England
Boose et al. (2001)
85 yr
150 yr
380 yr
>380 yr
Approximate returninterval of damaging(F2) hurricanes in New England.
Boose et al. (2001)
Wilson 2005
Lumber Exports (Wilson 2005) vs Witness Trees Projections (Lorimer 1977): very different estimates of the prominence of white pine (>10x), indicating a large difference in the frequency and scale of disturbance in these forests.
Northern Hardwoods
seedling/sapling (1-15 yrs): 1-3%young pole (15-30 yrs): 1-3%
2-6%
Pitch Pine- Scrub Oakseedling/sapling: 10-30%young pole: 10-30%
20-60%
(Lorimer and White 2003)
Trani et al. (2001)
9%
4%
Early-successional forests in the eastern U.S.
What AboutBiotic Disturbances?
Contemporary Herbivores
flooded forest pond wet meadow shrubs forest
Open water areas created by beaver dams on the Kabetogama Peninsula, northern MN.
1940: 1% of area
1986: 13% of area
Johnston and Naiman (1990)
How large an area affected?
Northern Hardwoods
seedling/sapling 1-3%young pole 1-3%
beaver flowages ~3.5% (Gotie and Jenks 1982) 5-11%
(Lorimer and White 2003)
Even if we can accurately estimate HRNV,are these values relevant
in contemporary landscapes?
40/mi2
1100/mi2
POPULATION DENSITY
Hoving (2001)
Road Density in the Northeast
0
20
40
60
80
100C
OM
PO
SIT
ION
(%
)
0
20
40
60
80
100
120
140 RA
CC
OO
N/C
AN
ID T
RA
CK
S
CANIDS
RACCOONS
LA
ND
SC
AP
E
FO
R
DE
VAG
R
2.5 ha 5 haWinter
mortality: 69% 35%
Patches
OCT NOV DEC JAN FEB MAR APR MAY
FO
OD
QU
ALI
TY LARGE
PATCHESSMALL PATCHES
THRESHOLD?
CONDITION-SENSITIVE PREDATION
9 JA
N
16 J
AN
23 J
AN
30 J
AN
6 F
EB
13 F
EB
20 F
EB
27 F
EB
6 M
AR
13 M
AR
20 M
AR
27 M
AR
3 A
PR
10 A
PR
0
2
4
6
8
10
12
UN
:C R
AT
IO
4
3 3
34 5
6
3
2
5
13
11
13
13
12
6
2
9 7 7 8 5
5
5
8
544
New approaches needed to provide habitat
Parcelization or Fragmentation
potential to mimic natural
disturbances
restoration of shrublands/modified disturbance regime
(“sliding scale”)
modified disturbances (large and
clustered/connected)
limited extreme
Fore
st A
ge
you
ng
old
MANAGING INDUCED METAPOPULATIONS:may require deviating from HRNV
ME
NHVT
NYMA
CT
RI
DESCRIBING HABITAT DISTURBANCES
Size FrequencyIntensity
Do natural disturbance regimes provide realistic guidelines for
managing early-successional habitats in New England forests?
Human-generated disturbances
Pisgah Forest in southwestern New Hampshire three years after 1938 hurricane.