Invasive plants show more plasticity than native plants Irene Weber University of Washington HHMI...
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Transcript of Invasive plants show more plasticity than native plants Irene Weber University of Washington HHMI...
Invasive plants show more plasticity than
native plantsIrene Weber
University of Washington HHMI Integrative Research Internship
What is an invasive plant?
Invasive plants are introduced species that can thrive in areas beyond their natural range of dispersal. These plants are characteristically adaptable, aggressive, and have a high reproductive capacity.
USDA National Invasive Species Information Center
Why do we care about invasive plants?
Why do some plants invade?• Ability to reproduce sexually and
asexually• Rapid growth• High tolerance of heterogeneity• Predator release• Phenotypic plasticity in changing
environments
Baker 1965 Sakeital 2001
Full sun conditions
Shade conditions
Poor plasticity
Plant showing plasticity
What is Plasticity?
Plasticity in Invasive Species Rumex acetosella vs. Rumex venosus
Invasive Species Non Invasive Species
SI=((number of stomata)/(total cells: stomata + epidermal)) x 100
((6)/(6+34))x100 = 15
Stomatal Index
Methods
Hypotheses
Pre-industrial stomatal index Stomatal index today
Invasive
Native
5
7
9
11
13
15
17
19
21
1880 1900 1920 1940 1960 1980 2000
Year plant collected
Sto
mat
al In
dex
Results
Rumex acetosella y = -
0.0264x + 63.985 R2 = 0.2013
Rumex venosus y = -0.0208x + 55.504 R2 = 0.1351
0
20
40
60
80
100
Invasive SpeciesRumex acetosella
22% SI decrease
Native SpeciesRumex venosus
14% SI decrease
Stomatal Index% Decrease
Conclusions
• The invasive plant shows a greater overall change in stomatal index than the native
• The invasive plant had a greater rate of change than the native plant
Discussion
• This shows a difference in the way that these two species respond in correlation with CO2 increases in the atmosphere
• This is evidence for the plasticity theory of invasive species
Future Directions
• Does this trend hold up for other plants?
• Is this purely due to plasticity or is there a microevolution effect?
Acknowledgements
University of Washington HHMI Integrative Research Internship
Janneke Hille Ris Lambers, UW Department of Biology
Soo-Hyung Kim and Nicole Hackman, UW College of Forest Resources
UW Herbarium and the OSU Herbarium
Questions?