Positive interactions between the lichen Usnea antarctica (Parmeliaceae) and the native flora in Maritime Antarctica. (25th September 2012)

• Record Type: Journal Article
• Authors: Molina‐Montenegro, Marco A.; Ricote‐Martínez, Natalia; Muñoz‐Ramírez, Carlos; Gómez‐González, Susana; Torres‐Díaz, Cristian; Salgado‐Luarte, Cristian; Gianoli, Ernesto; Woods, Kerry
• Is Part Of: Journal of vegetation science. Volume 24:Number 3(2013:May)
• Page Start: 463
• Page End: 472
• Publication Date: 2012-09-25
• Subjects: Plant ecology -- Periodicals; Plant communities -- Periodicals; Plant populations -- Periodicals; 581.7
• DOI: 10.1111/j.1654-1103.2012.01480.x
• Languages: English
• ISSNs: 1100-9233

Abstract

<abstract abstract-type="main" id="jvs1480-abs-0001"> <title>Abstract</title> <sec id="jvs1480-sec-0001" sec-type="section"> <title>Questions</title> <p>Is the macrolichen <italic>Usnea antarctica</italic> a 'nurse' species to Antarctic flora? Are positive plant–plant interactions more frequent than negative interactions in Antarctic ecosystems? Are microclimatic modifications by cushions of <italic>U. antarctica</italic> responsible for the nurse effect?</p> </sec> <sec id="jvs1480-sec-0002" sec-type="section"> <title>Location</title> <p>Two sites in Antarctica: King George Island, South Shetland (62°11′ S, 58°56′ W; 62°11′ S, 58°59′ W).</p> </sec> <sec id="jvs1480-sec-0003" sec-type="section"> <title>Methods</title> <p>We evaluated the association of plant species with <italic>U. antarctica</italic> cushions by recording species growing – in equivalent areas – within and outside <italic>U. antarctica</italic> cushions. Additionally, we performed transplant experiments with <italic>Deschampsia antarctica</italic> individuals to assess if <italic>U. antarctica</italic> cushions enhance plant survival. In both study sites we monitored temperature, moisture and nutrient status of soil outside and within the cushions to provide insights into potential mechanisms underlying possible interactions between <italic>U. antarctica</italic> and other plant species.</p> </sec> <sec id="jvs1480-sec-0004" sec-type="section"> <title>Results</title> <p>Eight out of 13 species were positively associated with cushions of the widespread lichen <italic>U. antarctica</italic>, while only one species (<italic>U. aurantiaco‐atra</italic>) showed a negative association with <italic>U. antarctica</italic>. Survival of <italic>Deschampsia</italic> was enhanced when growing associated with <italic>U. antarctica</italic> cushions. Our results indicate that cushions ameliorated the extreme conditions of Antarctic islands through increased temperature and soil moisture, decreased radiation and evaporative water loss and increased nutrient availability.</p> </sec> <sec id="jvs1480-sec-0005" sec-type="section"> <title>Conclusions</title> <p>The nurse effect of <italic>U. antarctica</italic> is verified. Cushions of this macrolichen may be a key component in structuring the Antarctic landscape and maintaining local species richness, and their presence might influence range expansion of other species.</p> </sec> </abstract>