C. rossicum’s invasion of North America appears to include a very long lag phase (about 100 years) after initial naturalization, followed by an exponentially rapid phase of spread. Researchers believe that the species displays an Allee effect - a reproductive feedback in small plant populations in which population density and reproductive and survival rates are strongly positively correlated (Kricsfalusy & Miller, 2009; Cappuccino, 2004).
There appears to be a physiological dormancy requirement for C. rossicum seeds, as under experimental conditions, high degrees of germination (greater than 90%) are only found in seeds that are subjected to a stratification treatment of three months (Douglass et al, 2009). Tufted seeds are released from follicles and disperse in late summer and fall (Cappuccino, 2004). Observations indicate that a large proportion of seeds remains close to the parent plant, though small, satellite populations are often found downwind of large seed source populations (Lawlor, 2009). A typical C. rossicum stand can produce as many as 54,000 seedlings per m² annually (Smith et al., 2006). Root crown fragments support dormant buds that readily sprout if not destroyed (PCA, 2006).
Principal source: DiTommaso, Antonio; Frances M. Lawlor; Stephen J. Darbyshire, 2005. The biology of invasive alien plants in Canada. 2. Cynanchum rossicum (Kleopow) Borhidi [= Vincetoxicum rossicum (Kleopow) Barbar.] and Cynanchum louiseae (L.) Kartesz & Gandhi [= Vincetoxicum nigrum (L.) Moench]. Canadian Journal of Plant Science. 85(1). JAN 05. 243-263.
Douglass, C. H.; L. A. Weston and A. DiTommaso., 2009. Black and Pale Swallow-Wort (Vincetoxicum nigrum and V. rossicum): The Biology and Ecology of Two Perennial, Exotic and Invasive Vines. Invading Nature – Springer Series In Invasion Ecology Management of Invasive Weeds Volume 5
Averill, K.M., Ditommaso, A., Mohler, C.L., Milbrath, L.R. 2008. The Invasive Swallow-worts: What Do We Know About Their Biology and Management?. International Allelopathy Congress. p. 71-71.
Plant Conservation Alliance (PCA) 2006. Alien Plant Working Group Least Wanted: Pale Swallow-wort Cynanchum rossicum (Kleopov) Barbarich Milkweed family (Asclepiadaceae). Author: Fran Lawlor, Central and Western New York Chapter, The Nature Conservancy, Pulaski, NY
Compiler: National Biological Information Infrastructure (NBII) & IUCN/SSC Invasive Species Specialist Group (ISSG)
Review: Cameron H. Douglass, Department of Bioagricultural Sciences & Pest Management, Colorado State University.
Publication date: 2010-08-04
Recommended citation: Global Invasive Species Database (2024) Species profile: Cynanchum rossicum. Downloaded from http://www.iucngisd.org/gisd/speciesname/Cynanchum+rossicum on 08-12-2024.
C. rossicum possesses various allelopathic abilities. For example, plant roots and fruits contain at least two compounds (including (-)-antofine) that have pronounced anti-fungal and anti-feedant activity (Mogg et al., 2008). Leaves release leachates as they decay that negatively affect germination and growth of indicator species (Douglass et al., in press). These root exudates and tissue leachates may play an important role in altering soil microbial and mycorrhizal communities, changes that appear to facilitate C. rossicum’s invasive ability (DiTommaso et al., 2005; Douglass et al., 2009; Smith et alIn New York state alone, C. rossicum displaces and threatens 23 rare plant species and six rare animal species. It has caused significant reductions in arthropod diversity, especially in old field communities, and thus indirectly affects wildlife that prey on insect communities (Averill et al, 2008b; Ernst & Cappuccino, 2005). C. rossicum serves as a population sink for monarch butterflies by attracting oviposition despite being an unsuitable host for larval development. It also displaces common milkweed (Asclepias syriaca), the primary native host for monarch butterflies (Danaus plexippus) (Averill et al., 2008b; Mattila & Gard, 2003; DiTommaso & Antonio, 2003). Dense stands of C. rossicum deter grassland birds from typical nesting habitats in the summer, and can inhibit predation by raptors of small rodents who can take refuge under the abundant and dense senesced plant material during the winter (Averill et al., 2008b; DiTommaso et al., 2005). \r\n
C. rossicum threatens globally-rare alvar communities in the Great Lakes region - which are composed of a unique mixture of sparsely vegetated rock, grassland, and savanna barrens that develop on thin soils over glaciated limestone or dolostone bedrock. Research indicates that C. rossicum populations modify soil microbial communities, thereby displacing sensitive native plant species whose survival depends on unique microbial associations (Averill et al., 2008b; PCA, 2006; Smith et al., 2008). \r\n
C. rossicum has negative effects in agricultural and horticultural ecosystems as well. Christmas tree growers in central New York state have reported increased problems stemming from invasions of the species in plantations, especially within the last decade. Orchard owners east of Rochester, NY cited C. rossicum as their most problematic weed species, since it rapidly and severely alters abiotic and biotic features of tree understories by: decreasing sunlight penetration; increasing nutrient and water acquisition (swallow-wort species have abnormally high root to shoot biomass ratios); and altering rhizosphere dynamics both through shifts in the mycorrhizal communities and the exudation of allelopathic chemicals. Horticultural nursery owners and Christmas tree producers affected by pale swallow-wort infestations have reported that due to a lack of effective control methods, land abandonment was often the most reasonable option (Douglass et al., 2009). Furthermore, C. rossicum has become problematic in no-till corn and soybean fields in several central and western New York State counties. Finally it serves as a host for various insect pests of crops and as an alternate host of Cronartium rusts that attack Pinus species (DiTommaso et al., 2005).
The noctuid moth Hypena opulenta was discovered feeding on C. rossicum in Ukraine and is being investigated as a potential biological control agent. H. opulenta adults and larvae feed on C. rossicum, and studies have found that releases decreased reproductive output (specifically flower, seedpod, and seed production) in C. rossicum (Weed & Casagrande, 2010). \r\n
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