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Title: Does soil pH influence swallow-wort distribution in its current range?

item Milbrath, Lindsey

Submitted to: Proceedings of Northeastern Weed Science Society
Publication Type: Abstract Only
Publication Acceptance Date: 11/15/2007
Publication Date: 1/7/2008
Citation: Magidow,, L.C., Ditommaso,, A., Ketterings,, Q.M., Milbrath, L.R. 2008. Does soil pH influence swallow-wort distribution in its current range?. In: G. R. Armel (Ed.), Proceedings of 62nd Annual Meeting of the Northeastern Weed Science Society. p. 21.

Interpretive Summary:

Technical Abstract: The perennial non-native vines, pale swallow-wort (Cynanchum rossicum [Kleopow] Borhidi) and black swallow-wort (Cynanchum louiseae [L.] Kartesz & Gandhi), are established invaders in the northeastern United States and southeastern Canada, and are spreading westward. The swallow-worts typically colonize forest-field margins, road edges, tree nurseries, and rare limestone barrens. In open areas they can form dense, monospecific stands, where they out-compete and displace resident vegetation. Previous research and observation indicate that these vines may occupy distinct ranges, with pale swallow-wort associated with basic, limestone-based soils, while black swallow-wort is associated with more acidic soils. To gain a better understanding of the chemical characteristics of soils colonized by these two swallow-wort species, soil samples were collected by volunteers across the distribution range of these plants. Samples were then submitted to the Cornell Nutrient Analysis Laboratory for chemical analysis. As of October 2007, nearly 100 samples were received from over 25 volunteers, with new samples arriving weekly. Preliminary results indicate that pale swallow-wort occurs on soils with an average pH = 6.7, and ranging from 4.7 to 7.9, and black swallow-wort occurs on soils with an average pH = 6.4, and ranging from 5.2 to 8.0. Despite the similar range in pH of soils colonized by these two species, the geographic distributions of pale and black swallow-wort do appear distinct. These preliminary findings suggest that differences in pH of soils colonized by the two swallow-wort species may not be an important factor influencing the current distribution pattern of these two invasive vines.