E X P E R I E N C E Y O U R A M E R I C A
Exotic-Invasive Plants
John Paul SchmitGeorge Wright Society MeetingMarch 2011
National Park ServiceU.S. Department of the InteriorNational Capital Region Network
Exotic Invasive PlantsQuestions
Can we determine what makes some parks more vulnerable?
Can we determine what areas in parks might be more vulnerable?
Are there any species that show up in a certain type of habitat?
Exotic Invasive PlantsData
5 networks (ERMN, MIDN, NCBN,NCRN, NETN) and 2 prototype parks (CACO, SHEN)
List of the 33 worst exotic invasives (commonly found and problematic), plus any woody trees and shrubs
Total of 65 species from 40 parks, 1623 plots, 3094 observations of exotic-invasive plants
Invasives are Common in Forest Plots
E X P E R I E N C E Y O U R A M E R I C A
ALP
OB
LUE
DE
WA
FON
EFR
HI
GA
RI
JOFL
NE
RI
AP
CO
BO
WA
FRS
PG
ETT
GE
WA
HO
FUP
ETE
RIC
HS
HE
NV
AFO
CA
CO
SA
HI
THS
TA
NTI
CA
TOC
HO
HG
WM
PH
AFE
MA
NA
MO
NO
NA
CE
PR
WI
RO
CR
WO
TRA
CA
DM
AB
IM
IMA
MO
RR
RO
VA
SA
GA
SA
RA
WE
FA
% o
f Plo
ts In
vade
d
0.0
0.2
0.4
0.6
0.8
1.0NETNMIDN NCBN NCRNERMN
# of Exotic Species found per Park
E X P E R I E N C E Y O U R A M E R I C A
ALP
OB
LUE
DE
WA
FON
EFR
HI
GA
RI
JOFL
NE
RI
AP
CO
BO
WA
FRS
PG
ETT
GE
WA
HO
FUP
ETE
RIC
HS
HE
NV
AFO
CA
CO
SA
HI
THS
TA
NTI
CA
TOC
HO
HG
WM
PH
AFE
MA
NA
MO
NO
NA
CE
PR
WI
RO
CR
WO
TRA
CA
DM
AB
IM
IMA
MO
RR
RO
VA
SA
GA
SA
RA
WE
FA
# of
Exo
itc In
vasi
ves
Spe
cies
0
5
10
15
20
25
30
35NETNMIDN NCBN NCRNERMN
E X P E R I E N C E Y O U R A M E R I C A
The Worst Plot:Fort Circle Parks –Washington D.C.14 Exotic Species
E X P E R I E N C E Y O U R A M E R I C A
Species Common Name
Growth Habit Parks(n=40)
Plots(n=1623)
Lonicera japonica
Japanese honeysuckle
Vine 35 337
Microstegium vimineum
Japanese stiltgrass
Herb 31 375
Rosa multiflora
Multiflora rose Shrub/Vine 31 316
Berberis thunbergii
Japanese barberry
Shrub 29 222
Alliaria petiolata
Garlic mustard Herb 25 346
Polygonum caespitosum
Oriental lady’s thumb
Herb 25 183
Celastrus orbiculatus
Oriental bittersweet
Vine 24 188
Rubus phoenicolasius
Wine berry Shrub 20 129
What Factors are Related to Differences in Exotic Invasives between Parks?
• Park Area
• Forested Area
• % of Park Forested
• Distance to nearest:• Park Boundary
• Road• River
• Elevation
• 2009 Visitation
• Latitude
E X P E R I E N C E Y O U R A M E R I C A
E X P E R I E N C E Y O U R A M E R I C A
% of Forest Plots Invaded by Park
Forested Area of Park (ha)
10 100 1000 10000 100000
% o
f For
est P
lots
with
Exo
tic In
vasi
ves
0.0
0.2
0.4
0.6
0.8
1.0
Eastern Rivers and MountainsMid-AtlanticNorth Coast and BarrierNational CapitalNorth East Temperate
p<0.0001R2
adj=30.4%
E X P E R I E N C E Y O U R A M E R I C A
Number of Exotic Invasives per Park
Visitors in 2009
10000 100000 1000000 10000000Tota
l Num
ber o
f Exo
tic In
vasi
ves
Foun
d on
all
Plo
ts
0
5
10
15
20
25
30
35Eastern Rivers and MountainsMid-AtlanticNorth Coast and BarrierNational CapitalNorth East Temperate
p<0.001R2
adj=27.6%
E X P E R I E N C E Y O U R A M E R I C A
Exotics per Plot by Park
Visitors in 2009/Forest area (ha)
10 100 1000 10000
Num
ber o
f Exo
tic/In
vasi
ves
per p
lot
0
2
4
6
8Eastern Rivers and MountainsMid-AtlanticNorth Coast and BarrierNational CapitalNorth East Temperate
p=0.007R2
adj=15.3%
Exotic/Invasive Plants within Parks Can we predict which plots are more likely to have exotic
plants?
Examined 5 parks with 100+ plots (DEWA, FRSP, NERI, PRWI, SHEN)
Logistic regression
Predictors:• Distance to nearest:
• Park Boundary• Road• River
• Elevation
E X P E R I E N C E Y O U R A M E R I C A
What Predicts Invaded Plots?
E X P E R I E N C E Y O U R A M E R I C A
Park Road Distance
Boundary Distance
River Distance
Elevation
Delaware Water Gap
n.s. n.s. n.s. Low Elevation
Fredericksburg-Spotsylvania
n.s. n.s. n.s. Low Elevation
New River Gorge
n.s n.s. n.s. Low Elevation
Prince William Forest
n.s. n.s. Close to Rivers
Low Elevation
Shenandoah n.s n.s n.s. n.s.
Predicting the Occurrence of Individual Species- What characterizes the parks where a species
is found?
- Where is the species found within parks?
E X P E R I E N C E Y O U R A M E R I C A
What Predicts Presence in Parks?
E X P E R I E N C E Y O U R A M E R I C A
Species % Forest Elevation Latitude Distance to Road or River
Lonicera japonica Less forest Low elevation Low latitude n.s.
Microstegium vimineum
Less forest n.s. n.s. n.s.
Rosa multiflora
n.s High elevation n.s. Close to rivers and roads
What Predicts Lonicera japonica Invaded Plots?
E X P E R I E N C E Y O U R A M E R I C A
% of Plots Invaded
Distance to Road, River or Edge
Elevation
Delaware Water Gap 4.9% n.s. n.s
Fredericksburg-Spotsylvania
11.4% Close n.s.
New River Gorge 6.0% n.s n.s.Prince William Forest 17.1% Close n.s.
Shenandoah 12.5% n.s. n.s.