Investigating potential determinants of the distribution limits of a savanna woody plant: Colophospermum mopane. (13th June 2013)

• Record Type: Journal Article
• Authors: Stevens, Nicola; Swemmer, Anthony M.; Ezzy, Leanne; Erasmus, Barend F.N.; Ward, David
• Is Part Of: Journal of vegetation science. Volume 25:Number 2(2014)
• Page Start: 363
• Page End: 373
• Publication Date: 2013-06-13
• Subjects: Plant ecology -- Periodicals; Plant communities -- Periodicals; Plant populations -- Periodicals; 581.7
• DOI: 10.1111/jvs.12098
• Languages: English
• ISSNs: 1100-9233

Abstract

<abstract abstract-type="main" id="jvs12098-abs-0001"> <title>Abstract</title> <sec id="jvs12098-sec-0001" sec-type="section"> <title>Questions</title> <p>Early bioclimatic models predict that climate change in southern African savannas will cause a huge southward and westward range shift of the savanna tree <italic>Colophospermum mopane</italic> (Kirk ex Benth.) Kirk ex J.Léon. <italic>C. mopane</italic> is an economically and ecologically important subtropical savanna tree that forms mono‐dominant stands across 30% of southern African savannas. We investigate the validity of these initial range expansion predictions to answer the following questions: what are the regional‐scale drivers of the distribution of <italic>C. mopane</italic> in southern African savannas; and what are the landscape‐scale distribution patterns of this species?</p> </sec> <sec id="jvs12098-sec-0002" sec-type="section"> <title>Location</title> <p>Central Lowveld, Kruger National Park, South Africa.</p> </sec> <sec id="jvs12098-sec-0003" sec-type="section"> <title>Methods</title> <p>We investigate the validity of very early range expansion modelling predictions using a regional‐scale, climate envelope niche model, and fine‐scale field mapping of the current boundary, to understand which environmental variables may determine the distribution limit of this signature species.</p> </sec> <sec id="jvs12098-sec-0004" sec-type="section"> <title>Results</title> <p>Our findings indicate that both non‐climatic (dry season day length) and climatic (minimum temperatures) variables limit the regional distribution of <italic>C. mopane</italic>. At the landscape scale, the distribution of this species is restricted to the warmer parts of the landscape, suggesting minimum temperature appears to be the primary factor determining its landscape‐scale distribution.</p> </sec> <sec id="jvs12098-sec-0005" sec-type="section"> <title>Conclusions</title> <p>This study provides the first detailed model of environmental factors that may limit the regional distribution of <italic>C. mopane</italic>, and allows us to formulate testable hypotheses regarding the determinants of the range of a keystone species.</p> </sec> </abstract>