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Testing community assembly theory in vernal pool restoration.
Collinge, Sharon*,1, 1 University of Colorado-Boulder, Boulder, Colorado
ABSTRACT- Ecological restoration projects present valuable opportunities to test basic ecological theory. I designed a field experiment with vernal pool plant communities in northern California to test hypotheses posed by community assembly theory. A key prediction from this theory is that the frequency of colonization attempts by a particular species significantly affects subsequent community composition. This ongoing field experiment involves construction and seeding of 256 vernal pools at Travis AFB, California. Two of the five seed addition treatments were used to compare plant species composition in pools seeded once (1x) with the endangered plant species, Lasthenia conjugens (Asteraceae) versus pools seeded three times (3x) with this species. After three years of study, L. conjugens was twice as abundant in 3x pools than in 1x pools (ANOVA p<0.01). This suggests that successful establishment by this species may require repeated colonization events. Additionally, the frequency of L. conjugens seeding significantly affected composition of the entire vascular plant community in sample plots. Ordination analyses revealed that plots seeded once with L. conjugens were clearly distinct from those seeded three times with L. conjugens. These data support the hypothesis that the frequency of colonization attempts by a particular species significantly influences performance of that species as well as the composition of the plant community. These results contribute to our understanding of community assembly processes and also provide guidelines for restoration of vernal pool plant communities.
KEY WORDS: assembly theory, restoration, Lasthenia conjugens, plant community ecology