Climate Change and Plant
Phenology in the Southeastern
United States
George R. Kish
U.S. Geological Survey
Tampa, Florida
E-Mail: gkish@usgs.gov
U.S. Department of the Interior
U.S. Geological Survey
Evidence

Key Findings
 Temperature
 Sea level
 Snow cover
© IPCC, 2007
Key Findings – Intergovernmental Panel
on Climate Change (IPCC)




Ecosystems on all continents affected
Globally ~20% to 30% of species will be at
increasingly high risk of extinction by 2100
Conservation practices poorly prepared for
adaptation
Effective adaptation will be costly
Projected climate change effects
for the Southeast by 2090


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Accelerated wildfire frequency – a warmer, longer dry
season
Increased human health risks from exposure to heat
Increased pest epidemics (pine bark beetles)
Sea-level rise in coastal areas
Reduced availability of soil moisture to plants
Changes in ecosystem community dynamics
 Soil drying leading to forest losses and savanna and grassland

increases
Both drought and fire play an important role in the forest breakup
Summer Heat
Heat Index = f (temperature, humidity)
Precipitation
Change
Soil Moisture
Change
Phenology

Phenology - Study of the timing of recurring
biological phases, the causes of their timing with
regard to biotic and abiotic forces, and the
interrelation among phases of same or different
species

Phenophase – Bud break, unfolding of first leaf,
flowering, fruiting, turning of leaves, animal
migration, emergence, growth stages, breeding,
nesting, hibernation, etc.
Syringa vulgaris
(common lilac)
Syringa chinensis
(cloned lilac)
Schwartz and Reiter 2000
International. J. Climatology
First Leaf = widest part of green
leaf past brown winter bud tips)
Spring index - first leaf date for lilacs
Trend
toward
earlier first
leaf date
Schwartz and Reiter, 2000
International. J. Climatology
Hu, Q., Weiss, A., Feng, S., &
Baenziger, P.S. (2006) Early
winter wheat heading dates
and warmer springs in the
U.S. Great Plains. Agricultural
and Forest Meteorology
135:284.
Heading date: when head
(spike) on 50% of the
Kharkof cultivar emerges
from the flag leaf.
Smithonian Natural History Museum



100 plants in D.C. area
89 showed earlier
blooming
Deadnettle
 Bloom 39 days earlier than
in 1970
Issues for Southeastern Phenology
1.
2.
3.
4.
Will heat tolerance of sensitive species cause shifts in
range?
Will water stress along hydrologic gradients cause
long-term shifts in plant community structure?
Are plants blooming or setting fruit earlier because of
climate change?
Will these shifts alter species diversity and the
function of ecosystems?
Species Range Shift
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Many species reach their southernmost range
in the Florida peninsula
Provides opportunity to monitor range shifts
Challenge – to isolate global climate change
from ecological and local weather processes
Liriodendron tulipifera (tulip tree)

Large (>100 ft tall) deciduous
tree typical of the mid-Atlantic
region

Southern limit – mid-peninsular
Florida

Monitoring phenology of key
species will provide evidence of
range shifts
Hydrologic Gradient Shift
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Soil drying may cause species or
community changes
Opportunities for exotic invasive plants
Long-term drying may permanently alter
community structure
A serious issue for protecting wetlands
USF EcoArea
Mesic
Hydric
Xeric
Hydrologic Gradient
Sandhill
(xyric)
Transition
(mesic)
Elevation (in ft above NGVD)
Land and Water Table Elevation
60.00
Land surface
elevation
50.00
Water level
elevation
40.00
30.00
Water level
elevation drought
20.00
10.00
0.00
0
100
200
300
400
500
Distance (in ft from site #1)
(Source: G.Kish, unpublished
data from USF EcoArea)
Cypress
Swamp
(hydric)
Longleaf pine
Scrub live oak
Turkey oak
Saw palmetto
Xeric Site
Laurel oak
Ferns
Mesic Site
Pop ash
High water line
Bald cypress
Hydric Site
 Longleaf pine, turkey
Species Distribution: Site 1
70
60
Dry
50
Percent
Species Distribution
 Xeric site
40
30
20
10
oak, scrub live oak
0
Pinus palustris
Quercus laevis
Quercus geminata
Species
Species Distribution: Site 4
Mesic site
 Laurel oak, slash pine
80
70
60
Percent

90
50
40
30
20
10
0
Quercus laurifolia
Hydric site
Species Distribution: Site 6
 Bald cypress, pop ash
80
70
60
Percent

Pinus elliottii
Species
50
40
30
20
Wet
10
0
Fraxinus caroliniana
Taxodium distichum
Species
Species Abundance
Monitoring Strategies for Change
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Life cycle – timing, vulnerability to heat and
water stress
Range – northward retreat or elimination of
heat-sensitive species; colonization by
opportunistic species
Hydrologic gradient - replacement of hydric
species along hydrologic gradients in
response to drought and hydroperiod
changes
Community structure
Tier 1
Tier 2
Tier 3
Tier 4
Intensive
Sites
AmeriFlux
NWS Coop
Spatially Extensive NPS Inv. & Mon.
State Ag. Exp. Sta.
Science Networks
Nature
Spatially Extensive
Preserves,
Volunteer & Education Networks
Campuses
Remote Sensing and
Synoptic (wall-to-wall) Data
NASA
USGS
NOAA
Increasing Process Knowledge
Data Quality
# of Measurements
Decreasing Spatial Coverage
USA-NPN Monitoring Framework
Southeastern Phenology Network Plans
 Uncover Legacy Data
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Citizen scientists
Biological Research Stations and Nature Preserves
Botanical Gardens and Herbariums
Theses and dissertations
 Southeastern Phenology Workshops
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Implement monitoring protocols for Southeast
Select Tier 1, 2, and 3 sites for Region
Develop remote sensing approach
Design web site
Develop priority research agenda