Title: Multi-year survival, growth and maturation of invasive swallow-wort juveniles (Vincetoxicum spp.) across a habitat gradient Authors
Submitted to: Weed Science Society of America Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: February 1, 2011
Publication Date: February 7, 2011
Citation: Milbrath, L.R., Ditommaso, A., Biazzo, J., Morris, S.H. 2011. Multi-year survival, growth and maturation of invasive swallow-wort juveniles (Vincetoxicum spp.) across a habitat gradient [abstract]. Weed Science Society of America Meeting Abstracts. 66 Available: http://wssaabstracts.com/public/4/abstract-66.html). Technical Abstract: Vincetoxicum rossicum, pale swallow-wort [PSW], and V. nigrum, black swallow-wort [BSW] are two non-native perennial vines that are increasingly problematic in many regions of the northeastern US and southern Canada. The two species can grow in full sun or shaded forest understories, and infest a variety of habitats from agricultural to natural areas. Seedling establishment and growth may be an especially critical phase in the life cycle of plants and may be targeted for control of invasive species if this stage is important for population growth. We established a long-term field experiment in fall of 2007 to assess survival and growth of early-stage swallow-worts in three different habitat types: an old field [high light], a forest edge [transition zone] and forest understory [low light] at a central New York State location where both species are present in the region although not at the experimental site. The two swallow-wort species were established from seed in a split plot design with habitat type as the whole plot treatment, swallow-wort species as the subplot treatment, and 10 blocks for a total of 60 subplots. From an initial cohort of 40 seedlings per subplot, survival and growth (i.e. height, time to first flower, seed production) of these seedlings have been monitored annually. After the third season of growth (2010), survival of black swallow-wort (31+/-4%) was greater than pale swallow-wort (6+/-2%). Survival of juvenile BSW plants was greater in the forest edge habitat (77+/-5%) than forest understory (49+/-6%) but not the old field (58+/-6%). Survival of PSW plants was similar among the forest edge (42+/-6%), old field (34+/-6%) and forest understory habitats (37+/-6%). Juvenile BSW plants remained 2.5-3.5 times taller than PSW in all habitats with the greatest differences in height between the species observed in the old field habitat. Since the start of the field study, only four BSW plants have flowered (one in 2009 and three in 2010), but none of the plants produced seed. The relatively low seedling establishment levels observed in this study especially for PSW are surprising given that this species typically thrives in high light, open habitats in the region. However, the dense cover of resident vegetation in the old field may have suppressed PSW establishment and growth more than the larger seeded BSW. Also, this research confirms the suitability of forest-old field transition zones (ecotone) for establishment and growth of these two swallow-wort species and suggests that management tactics be especially targeted in this habitat.