Handel, Steven , Clemants, Steven , Toth, Edward , Parag, Hadas , Chambers, Timothy .
Seed source specificity is not tightly associated with plant performance in a 3-year urban common garden experiment.
We tested the hypothesis that native plants growing in human-disturbed and polluted sites have genetically adapted to these conditions. We studied five species, all native to the New York City region: Asclepias syriaca, Eupatorium rugosum, Euthamia graminifolia, Panicum virgatum and Solidago canadensis. Seeds were collected for each species from five representative urban stressed microsites and one rural population within a 25 by 30km area. Plants grown from these seeds were planted in a random grid pattern at four urban test gardens (sanitary capped landfill, industrial fill, edge of highway, brownfield) and one rural test garden (post-agricultural). In each test garden, there were fifteen individuals of each species from each population (90 plants). Test gardens were watered and weeded only in the first year. Survivorship, plant volume and seed production were measured at the end of three years. Asclepias syriaca and Eupatorium rugosum showed high mortality at all sites and were not analyzed further. Euthamia graminifolia, Panicum virgatum and Solidago canadensis showed high survivorship. Plant volume and seed production were highly correlated for these three species. Plant size after three years was significantly related to test garden site for all three species. Seed source was not significantly related to plant performance except for Panicum virgatum; this may be because its rural seed source was much more distant (80km) from the urban seed sources than for the other species in the study. These data do not support a conclusion that there is genetic adaptation for the urban environment. Growth of plants within species was quite plastic, with wide variation in size of plants from a single source in different test garden conditions. These data also show that there was much greater growth on the post-agricultural site, followed by the sanitary landfill, than the other three test garden sites.
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1 - Rutgers University, Ecol Evol & Nat Res, 1 College Farm Rd, New Brunswick, New Jersey, 08901-1582, USA
2 - Brooklyn Botanic Garden, Science Department, 1000 Washington Avenue, Brooklyn, New York, 11225-1099, USA
3 - Greenbelt Native Plant Center, City of New York, Department of Parks & Recreation, 3808 Victory Blvd., Staten Island, NY, 10314, USA
4 - Rutgers University, 1 College Farm Road, New Brunswick, NJ, 08901-1582, USA
Presentation Type: Oral Paper:Papers for Sections
Date: Tuesday, July 29th, 2008
Time: 4:00 PM