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<oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd">
  <dc:contributor>Diane L. Larson</dc:contributor>
  <dc:creator>Laura C. Van Riper</dc:creator>
  <dc:date>2009</dc:date>
  <dc:description>This study examines the impact of the exotic nitrogen-fixing legume &lt;i&gt;Melilotus officinalis&lt;/i&gt; (L.) Lam. on native and exotic species cover in two Great Plains ecosystems in Badlands National Park, South Dakota. &lt;i&gt;Melilotus&lt;/i&gt; is still widely planted and its effects on native ecosystems are not well studied. &lt;i&gt;Melilotus&lt;/i&gt; could have direct effects on native plants, such as through competition or facilitation. Alternatively, &lt;i&gt;Melilotus&lt;/i&gt; may have indirect effects on natives, e.g., by favoring exotic species which in turn have a negative effect on native species. This study examined these interactions across a 4-year period in two contrasting vegetation types: Badlands sparse vegetation and western wheatgrass (&lt;i&gt;Pascopyrum smithii&lt;/i&gt;) mixed-grass prairie. Structural equation models were used to analyze the pathways through which &lt;i&gt;Melilotus&lt;/i&gt;, native species, and other exotic species interact over a series of 2-year time steps. &lt;i&gt;Melilotus&lt;/i&gt; can affect native and exotic species both in the current year and in the years after its death (a lag effect). A lag effect is possible because the death of a &lt;i&gt;Melilotus&lt;/i&gt; plant can leave an open, potentially nitrogen-enriched site on the landscape. The results showed that the relationship between &lt;i&gt;Melilotus&lt;/i&gt; and native and exotic species varied depending on the habitat and the year. In Badlands sparse vegetation, there was a consistent, strong, and positive relationship between &lt;i&gt;Melilotus&lt;/i&gt; cover and native and exotic species cover suggesting that &lt;i&gt;Melilotus&lt;/i&gt; is acting as a nurse plant and facilitating the growth of other species. In contrast, in western wheatgrass prairie, &lt;i&gt;Melilotus&lt;/i&gt; was acting as a weak competitor and had no consistent effect on other species. In both habitats, there was little evidence for a direct lag effect of &lt;i&gt;Melilotus&lt;/i&gt; on other species. Together, these results suggest both facilitative and competitive roles for &lt;i&gt;Melilotus&lt;/i&gt;, depending on the vegetation type it invades.</dc:description>
  <dc:format>application/pdf</dc:format>
  <dc:language>en</dc:language>
  <dc:publisher>Springer</dc:publisher>
  <dc:title>Role of invasive &lt;i&gt;Melilotus officinalis&lt;/i&gt; in two native plant communities</dc:title>
  <dc:type>article</dc:type>
</oai_dc:dc>