Beitrag
Phytosociology and ecology of treeline ecotone vegetation in Rolwaling Himal, Nepal
Bürzle, Birgit; Schickhoff, Udo; Schwab, Niels; Oldeland, Jens; Müller, Michael; Böhner, Jürgen; Chaudhary, Ram Prasad; Scholten, Thomas; Dickoré, Wolf Bernhard
Phytocoenologia Band 47 Heft 2 (2017), p. 197 - 220
132 Literaturangaben
veröffentlicht: Jul 20, 2017
Online veröffentlicht: May 30, 2017
Manuskript akzeptiert: Feb 1, 2017
Manuskript-Revision erhalten: Sep 10, 2016
Manuskript-Revision angefordert: Jan 30, 2017
Manuskript erhalten: Apr 21, 2016
ArtNo. ESP024004702004, Preis: 29.00 €
Abstract
Abstract Questions: Species composition and ecology of treeline vegetation types in the Rolwaling Valley is largely unknown to date. The aim of this study is to differentiate plant communities along the elevational gradient in the treeline ecotone, and to identify site factors which cause the differentiation of the treeline ecotone vegetation. Study area: Rolwaling Valley (27°52’ N; 86°25’ E) in the central Himalaya, Nepal. Methods: We included 91 phytosociological relevés along three elevational transects in this analysis, ranging from 3745 to 4300 m a.s.l. Plant communities were differentiated and vegetation-environment relationships analysed using cluster analysis and ordination. For each community and higher ranked unit, we detected diagnostic species according to their fidelity index (phi coefficient). Ecological preferences of each community were examined using one-way analysis of variance (ANOVA). Results and conclusions: We identified five communities, belonging to two different classes: the Synotis alata-Abies spectabilis and Ribes glaciale-Abies spectabilis communities occupy the upper part of the subalpine forest zone, representing the uppermost forest stands below treeline. These communities are primarily comprised of Abies spectabilis and Betula utilis in the tree layer, with varying cover of several tree species and distinct differences within the herb layer. Above treeline, the mixed forest stands are replaced by the species-poor Boschniakia himalaica-Rhododendron campanulatum community, forming a dense krummholz belt. We assigned the forest and krummholz communities to the class Betula utilis-Abies spectabilis forests. In the alpine zone two communities were classified and assigned to the class Dasiphora arbuscula-Rhododendron anthopogon dwarf shrub heaths.The species-poor Pedicularis cf. microcalyx-Rhododendron anthopogon community has a less developed herbaceous layer, whereas the Anaphalis royleana-Rhododendron anthopogon community is characterized by higher cover and higher species richness of herbs and grasses. Species composition of identified communities is mainly differentiated by soil temperature, nitrogen supply and availability, and soil moisture content. Nomenclature: The nomenclature of vascular plants follows Press et al. (2000) and Watson et al. (2011). Abbreviations: ANOVA = One-way analysis of variance; DCA = Detrended Correspondence Analysis; DJF = winter December to February; JJAS = summer/monsoon June to September; MAM = March to May; ON = autumn/post-monsoon October to November. Submitted: 21 April 2016; first decision: 10 September 2016; accepted: 1 February 2017
Schlagworte
Central Himalaya • classification • climate change • ecology • habitat condition • multivariate analysis • Nepal • ordination • phytosociology • Rolwaling Himal • treeline ecotone • vegetation