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Wanying Zhao, Charles Goebel, Andy Michel, and John Cardina
The Ohio State University
GENETIC AND AGE DISTRIBUTION PATTERN TO RECONSTRUCT THE INVASION HISTORY.
How to control invasive plant?
Sensitive habitat
1km
Sensitive habitat
What do we need for invasive plant control? • How long is the invasion history in a natural area?
• How fast is the invasion?
1950?
1960?
1970? 1970 1980 1990 2000
What do we need for invasive plant control? • How long is the invasion history in a natural area?
• How fast is the invasion?
• What is the spatial distribution pattern?
• How invasive plant spread over time?
Common privet (Ligustrum vulgare)
• Semi-evergreen shrub
• Oleaceae (olive family)
• 3-5m tall
• Produces many berries
• Spread by birds,
other animals
• Regenerates from root
and stump sprouts.
• Forms dense thickets
• Can displace native species
http://www.dreviny-okrasne.cz
Objectives
• To study the invasion history and spatial distribution pattern of Ligustrum vulgare over time and space in Wooster Memorial Park (WMP).
• Using chloroplast DNA markers to characterize spatial genetic structure in large scale and to describe how haplotypes spread in WMP.
Sample collection in Wooster Memorial Park
Sample collection in WMP • 345 samples
• ArcGIS version 10
Age determination
• Stem was sanded and scanned to image.
• Ages of 331 samples in Wooster Memorial Park were determined by tree ring counting in WinDendro.
• Age of each sample was put in ArcGIS-10.
Invasion history of L. vulgare in WMP
0
50
100
150
200
250
300
350
1970 1975 1980 1985 1990 1995 2000 2005 2010
Nu
mb
er
of
tota
l pat
che
s
Year
19 years
310 patches
19/year
12 patches
1972
Habitat preferences of initial patches
Age (No. of samples) Locations
39 (1), 28 (1), 21(1) Farm-upland forest
29 (1) Trail-stream-slope forest
28 (1), 22(1) Upland-slope forest
27 (1) Grassland-evergreen forest
25 (1), 23(1) Upland forest
22 (1) Bottomland forest (open area)
21 (1) Stream-bottomland forest
21 (1) Edge of the park (upland forest)
Spatial distribution pattern over time • Average Nearest Neighbor
• Spatial autocorrelation (Global Moran’s I)
• Hot spot analysis (Getis-Ord Gi*)
To describe how the samples distributed with respect to whether they were Geographically clustered, random or dispersed. To evaluation spatial distribution pattern of age with respect to if older or younger patches tend to be more closed to each other. To identify statistically significant spatial clusters of high values (old) and low values (young).
Average Nearest Neighbor
-3
-2
-1
0
1
2
3
4
5
1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010
Z s
core
Year
clustered
dispersed
random
Spatial Autocorrelation (Moran’s I)
-2
-1
0
1
2
3
4
5
6
1994 1996 1998 2000 2002 2004 2006 2008 2010
Z s
core
Year
dispersed
clustered
random
Hot spot analysis
Spatial genetic structure - Sampling
14
24
23 24
24
24 24 24
Wooster Memorial Park
Chloroplast DNA markers • cpDNA has been used as molecular marker in landscape genetics,
phylogeography and population genetics.
• Two cpDNA markers were characterized from Demesure et al. 1995.
• trnH and trnS
• Identified haplotypes of all the samples and calculated haplotype frequencies in each site.
Haplotype distribution map - trnH
Haplotype distribution map - trnS
Haplotype at trnH distribution in WMP
Haplotype at trnS distribution in WMP
Conclusions: Implications for management
• Early detection – Where?
• Target edge habitats.
• Spatially dispersed pattern.
• Control effort – When?
• About 20 years lag phase.
• Average 19 new patches per year after lag phase.
• Spatially spread – Random.
• There is no pattern related to landscape features.
• Hot spots and cold spots formation.
Acknowledgement • Committee members:
Dr. John Cardina, Dr. Andy Michel, Dr. Charles Goebel
• Lab members:
Cathy, Jenny, Sarahi, Lourdes
• Field group:
Peter, Nick, Heather
• Park managers
• Funding is supported by OARDC SEEDS interdisciplinary grant.