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Differences in Performance and Herbivory Along a Latitudinal Gradient for Common Burdock (Arctium minus)

Plant populations near the northern limits of their geographic distribution may experience different biotic pressures than southern populations. For instance, if herbivores are scarce in northern populations, performance of their host plants may benefit. In this study, I looked at populations of burdock (Arctium minus) along an 815 km latitudinal gradient from the northern range limit to more southern populations. I found that plant height, stem diameter, and number of seeds all increased on approaching the northern limit. In addition, I also found significant decreases in herbivory by generalist and specialist leaf and seed predators, even though northern plants invested less in physical and possibly chemical defenses. In an experiment in which seeds were planted in different soils, marginal soil initially produced smaller plants, but subsequently larger plants than soil from southern populations. These results indicate northern populations experience relaxed pressure from natural enemies and may benefit as a result.

Identiferoai:union.ndltd.org:TORONTO/oai:tspace.library.utoronto.ca:1807/32471
Date20 July 2012
CreatorsKambo, Dasvinder
ContributorsKotanen, Peter M.
Source SetsUniversity of Toronto
Languageen_ca
Detected LanguageEnglish
TypeThesis

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