Ecological resistance to Acer negundo invasion in a European riparian forest: relative importance of environmental and biotic drivers. Issue 2 (10th August 2012)

• Record Type: Journal Article
• Authors: Saccone, Patrick; Girel, Jacky; Pages, Jean‐Philippe; Brun, Jean‐Jacques; Michalet, Richard; Prober, Suzanne
• Is Part Of: Applied vegetation science. Volume 16:Issue 2(2013:Apr.)
• Page Start: 184
• Page End: 192
• Publication Date: 2012-08-10
• Subjects: Plant ecology -- Periodicals; Plant communities -- Periodicals; Plant populations -- Periodicals; Nature -- Effect of human beings on -- Periodicals; 581.705
• DOI: 10.1111/j.1654-109X.2012.01227.x
• Languages: English
• ISSNs: 1402-2001

Abstract

<abstract abstract-type="main" id="avsc1227-abs-0001"> <title>Abstract</title> <sec id="avsc1227-sec-0001" sec-type="section"> <title>Question</title> <p>The relative importance of environmental vs. biotic resistance of recipient ecological communities remains poorly understood in invasion ecology. <italic>Acer negundo</italic>, a North American tree, has widely invaded riparian forests throughout Europe at the ecotone between early‐ (<italic>Salix</italic> spp. and <italic>Populus</italic> spp.) and late‐successional (<italic>Fraxinus</italic> spp.) species. However, it is not present in the upper part of the Rhône River, where native <italic>Alnus incana</italic> occurs at an intermediate position along the successional riparian gradient. Is this absence of the invasive tree due to environmental or biotic resistance of the recipient communities, and in particular due to the presence of <italic>Alnus</italic>?</p> </sec> <sec id="avsc1227-sec-0002" sec-type="section"> <title>Location</title> <p>Upper Rhône River, France.</p> </sec> <sec id="avsc1227-sec-0003" sec-type="section"> <title>Methods</title> <p>We undertook a transplant experiment in an <italic>Alnus</italic>‐dominated community along the Upper Rhône River, where we compared <italic>Acer negundo</italic> survival and growth, with and without biotic interactions (tree and herb layer effects), to those of four native tree species from differing successional positions in the Upper Rhône communities (<italic>P. alba</italic>, <italic> S. alba</italic>, <italic> F. excelsior</italic> and <italic>Alnus incana</italic>).</p> </sec> <sec id="avsc1227-sec-0004" sec-type="section"> <title>Results</title> <p>Without biotic interactions <italic>Acer negundo</italic> performed similarly to native species, suggesting that the Upper Rhône floodplain is not protected from <italic>Acer</italic> invasion by a simple abiotic barrier. In contrast, this species performed less well than <italic>F. excelsior</italic> and <italic>Alnus incana</italic> in environments with intact tree and/or herb layers. <italic>Alnus</italic> showed the best growth rate in these conditions, indicating biotic resistance of the native plant community.</p> </sec> <sec id="avsc1227-sec-0005" sec-type="section"> <title>Conclusions</title> <p>We did not find evidence for an abiotic barrier to <italic>Acer negundo</italic> invasion of the Upper Rhône River floodplain communities, but our results suggest a biotic resistance. In particular, we demonstrated that (i) additive competitive effects of the tree and herb layer led to <italic>Acer negundo</italic> suppression and (ii) <italic>Alnus incana</italic> grew more rapidly than <italic>Acer negundo</italic> in this intermediate successional niche.</p> </sec> </abstract>