Limits...
Revealing historic invasion patterns and potential invasion sites for two non-native plant species.

Barney JN, Whitlow TH, Lembo AJ - PLoS ONE (2008)

Bottom Line: In contrast, in locations west of the 90(th) meridian, many populations never spread outside the founding county, probably a result of encountering unfavorable environmental conditions.Results show very few counties with high habitat suitability (>/=80%) remain un-invaded (5 for Japanese knotweed and 6 for mugwort), suggesting these perennials are reaching the limits of large-scale expansion.Despite differences in initial introduction loci and pathways, Japanese knotweed and mugwort demonstrate similar historic patterns of spread and show declining rates of regional expansion.

View Article: PubMed Central - PubMed

Affiliation: Department of Plant Sciences, University of California Davis, Davis, California, USA. jbarney@ucdavis.edu

ABSTRACT
The historical spatio-temporal distribution of invasive species is rarely documented, hampering efforts to understand invasion dynamics, especially at regional scales. Reconstructing historical invasions through use of herbarium records combined with spatial trend analysis and modeling can elucidate spreading patterns and identify susceptible habitats before invasion occurs. Two perennial species were chosen to contrast historic and potential phytogeographies: Japanese knotweed (Polygonum cuspidatum), introduced intentionally across the US; and mugwort (Artemisia vulgaris), introduced largely accidentally to coastal areas. Spatial analysis revealed that early in the invasion, both species have a stochastic distribution across the contiguous US, but east of the 90(th) meridian, which approximates the Mississippi River, quickly spread to adjacent counties in subsequent decades. In contrast, in locations west of the 90(th) meridian, many populations never spread outside the founding county, probably a result of encountering unfavorable environmental conditions. Regression analysis using variables categorized as environmental or anthropogenic accounted for 24% (Japanese knotweed) and 30% (mugwort) of the variation in the current distribution of each species. Results show very few counties with high habitat suitability (>/=80%) remain un-invaded (5 for Japanese knotweed and 6 for mugwort), suggesting these perennials are reaching the limits of large-scale expansion. Despite differences in initial introduction loci and pathways, Japanese knotweed and mugwort demonstrate similar historic patterns of spread and show declining rates of regional expansion. Invasion mitigation efforts should be concentrated on areas identified as highly susceptible that border invaded regions, as both species demonstrate secondary expansion from introduction loci.

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Habitat suitability of Japanese knotweed.Model predictions of habitat suitability based on the environmental and anthropogenic factors in Table 1.
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pone-0001635-g002: Habitat suitability of Japanese knotweed.Model predictions of habitat suitability based on the environmental and anthropogenic factors in Table 1.

Mentions: The spatial distribution of counties with high probabilities of Japanese knotweed is aggregated in the Northeast, Great Lakes region, and Pacific Northwest (Figure 2). Appalachia, from Alabama to Pennsylvania, also has moderately high probabilities of a Japanese knotweed invasion. However, the interior of the contiguous US has a very low (<25%) habitat suitability (Figure 2). Interestingly, despite several dozen counties in the Mid-Atlantic and southeastern Midwest with a Japanese knotweed population, the habitat suitability is very low.


Revealing historic invasion patterns and potential invasion sites for two non-native plant species.

Barney JN, Whitlow TH, Lembo AJ - PLoS ONE (2008)

Habitat suitability of Japanese knotweed.Model predictions of habitat suitability based on the environmental and anthropogenic factors in Table 1.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2238797&req=5

pone-0001635-g002: Habitat suitability of Japanese knotweed.Model predictions of habitat suitability based on the environmental and anthropogenic factors in Table 1.
Mentions: The spatial distribution of counties with high probabilities of Japanese knotweed is aggregated in the Northeast, Great Lakes region, and Pacific Northwest (Figure 2). Appalachia, from Alabama to Pennsylvania, also has moderately high probabilities of a Japanese knotweed invasion. However, the interior of the contiguous US has a very low (<25%) habitat suitability (Figure 2). Interestingly, despite several dozen counties in the Mid-Atlantic and southeastern Midwest with a Japanese knotweed population, the habitat suitability is very low.

Bottom Line: In contrast, in locations west of the 90(th) meridian, many populations never spread outside the founding county, probably a result of encountering unfavorable environmental conditions.Results show very few counties with high habitat suitability (>/=80%) remain un-invaded (5 for Japanese knotweed and 6 for mugwort), suggesting these perennials are reaching the limits of large-scale expansion.Despite differences in initial introduction loci and pathways, Japanese knotweed and mugwort demonstrate similar historic patterns of spread and show declining rates of regional expansion.

View Article: PubMed Central - PubMed

Affiliation: Department of Plant Sciences, University of California Davis, Davis, California, USA. jbarney@ucdavis.edu

ABSTRACT
The historical spatio-temporal distribution of invasive species is rarely documented, hampering efforts to understand invasion dynamics, especially at regional scales. Reconstructing historical invasions through use of herbarium records combined with spatial trend analysis and modeling can elucidate spreading patterns and identify susceptible habitats before invasion occurs. Two perennial species were chosen to contrast historic and potential phytogeographies: Japanese knotweed (Polygonum cuspidatum), introduced intentionally across the US; and mugwort (Artemisia vulgaris), introduced largely accidentally to coastal areas. Spatial analysis revealed that early in the invasion, both species have a stochastic distribution across the contiguous US, but east of the 90(th) meridian, which approximates the Mississippi River, quickly spread to adjacent counties in subsequent decades. In contrast, in locations west of the 90(th) meridian, many populations never spread outside the founding county, probably a result of encountering unfavorable environmental conditions. Regression analysis using variables categorized as environmental or anthropogenic accounted for 24% (Japanese knotweed) and 30% (mugwort) of the variation in the current distribution of each species. Results show very few counties with high habitat suitability (>/=80%) remain un-invaded (5 for Japanese knotweed and 6 for mugwort), suggesting these perennials are reaching the limits of large-scale expansion. Despite differences in initial introduction loci and pathways, Japanese knotweed and mugwort demonstrate similar historic patterns of spread and show declining rates of regional expansion. Invasion mitigation efforts should be concentrated on areas identified as highly susceptible that border invaded regions, as both species demonstrate secondary expansion from introduction loci.

Show MeSH
Related in: MedlinePlus