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Einar Eberhardt:

Plant life of the Karakorum

The vegetation of the upper Hunza catchment (Northern Areas, Pakistan). Diversity, syntaxonomy, distribution

2004. 223 pages, 32 figures, 21 tables, 1 CD-ROM, 14x23cm, 460 g
Language: English

(Dissertationes Botanicae, Band 387)

ISBN 978-3-443-64300-3, paperback, price: 70.00 €

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Keywords

vegetation diversity syntaxonomie distribution floristic Vegetation Diversität Syntaxonomie Verbreitung floristisch

Contents

Abstract top ↑

Investigations into the floristic inventory, diversity and vegetation ecology were carried out in the upper Hunza catchment, W Karakorum (Northern Areas, Pakistan) over almost the entire altitudinal gradient of vascular plant distribution (2450 - 4900 m). Latitudinal and altitudinal patterns of the distribution of individual plant species, of life-form spectra, species richness and species turnover as well as vegetation patterns are analysed. Altitudinal species turnovers are very high throughout the study area, but do not vary significantly with altitude. Latitudinal patterns reflect the major regional climatic gradient of decreasing precipitation, from the monsoon-influenced Himalayas to the deserts of Central and High Asia. The vegetation formations of the Batura Valley are surveyed on a medium-scale vegetation map (1 : 60 000). They display a clear altitudinal zonation, modified by the substantial effects of ice-masses and cold-air currents. A syntaxonomical system of the vegetation types of the Karakorum includes data from the Central Karakorum (Biafo) and Ladakh. Significance of indicator species is approached statistically. Vegetation units are discussed with regard to their possible indication of climate, substrate and human impact. An annotated checklist of the vascular plants of the study area is included.

Kurzfassung top ↑

Untersuchungen zum Inventar an Gefäßpflanzenarten, ihrer Diversitäts- und Vergesellschaftungsmuster sowie zur Vegetationsökologie wurden im oberen Einzugsgebiet des Hunza River (West-Karakorum, Northern Areas, Pakistan) durchgeführt über nahezu den gesamten Höhenbereich der Gefäßpflanzenverbreitung (2450 - 4900 m). Die horizontalen und vertikalen Muster der Verbreitung von Pflanzenarten, Lebensformenspektren, Artenreichtum und Artenwandel sowie der Vegetation werden untersucht. Der Artenwandel entlang des Höhengradienten ist sehr hoch, aber zeigt keine signifikante Variation mit der Höhe. Die horizontalen Verbreitungsmuster spiegeln den großräumigen Niederschlagsgradienten vom monsun-beeinflußten Himalaya zu den hoch- und zentralasiatischen Wüsten. Die Pflanzenformationen des Batura-Tals wurden im Maßstab 1 : 60 000 kartiert. Sie zeigen eine klare Höhenstufung, die durch große Gletschereismassen und Klatluftströme lokal modifiziert ist. Ein pflanzensoziologisches System des Karakorum bezieht Daten vom Zentralkarakorum und aus Ladakh ein. Die Eignung der Differentialarten wird statistisch abgesichert. Die Pflanzengesellschaften werden hinsichtlich ihrer Zeigereigenschaft für Klima, Substrat und menschliche Beeinflussung untersucht. Eine kommentierte Liste der Gefäßpflanzenarten des Arbeitsgebietes ist beigefügt.

Bespr.: Tuexenia 25, 2005 top ↑

Diese Dissertation stammt aus der Arbeitsgruppe von G. Miehe in Marburg, in der seit langem geobotanische Forschungen in asiatischen Gebirgen durchgeführt werden. Die daraus resultierenden Erwartungen für eine fundierte Bearbeitung werden voll erfüllt. Das Untersuchungsgebiet im nordöstlichen Pakistan liegt im schwer erreichbaren Einzugsgebiet des Flusses Hunza mit mehreren Tälern und erstreckt sich von Tallagen bei 2450 ­ 3700 m bis zu etwa 5000 m Höhe, wo jedes Pflanzenleben aufhört. Es herrscht ein trocken-kaltes Hochgebirgsklima, das vorwiegend steppenartige Vegetation (unter Beweidung) und offene Gehölzbestände zulässt. Im ersten Teil erfolgt eine floristische Analyse aus umfangreichen eigenen Erfassungen, die eine Gesamtliste von 528 Gefäßpflanzensippen ergibt. Sie richtet sich vor allem auf die Verteilung der Sippen, Geoelemente und Lebensformen entlang des Höhengradienten, der zwar eine Höhenstufung der Vegetation, aber keine entsprechenden Artensprünge erkennen lässt. 414 Braun-Blanquet-Vegetationsaufnahmen sind Grundlage für eine detaillierte pflanzensoziologische Bearbeitung mit einer erstmaligen syntaxonomischen Gliederung, die im Zusammenhang mit publizierten Aufnahmen aus Nachbargebieten einen überregionalen Charakter gewinnt. So werden u. a. 35 Assoziationen von Gebirgssteppen, Wacholder- Offenwäldern sowie von Sanddorn- und Weidengebüschen neu beschrieben und ebenfalls neuen Unterverbänden und Verbänden zugeordnet. Die Formationen und Gesellschaften werden in ihrer Verbreitung näher erörtert. Die farbige Vegetationskarte eines Tales zeigt grundlegende Anordnungsprinzipien.

Mehrere große, übersichtlich gegliederte Vegetationstabellen befinden sich (wie auch die Karte) auf der beiliegenden CD-Rom. Dies ist platz- und kostensparend, allerdings wenig leserfreundlich. Unmittelbar auf dem Bildschirm lassen sich die Tabellen nicht lesen: entweder ist die Schrift zu klein, oder man hat nur zusammenhanglose Teile im Blick. Damit geht der Sinn einer leicht überschaubaren Übersicht vieler Vegetationsdaten verloren. Mit einem normalen Drucker lassen sich die Tabellen auch nicht in lesbarer Größe ausdrucken, was ohnehin dem Nutzer zugemutet wird. Die kleineren Tabellen hätten gut in den Text integriert werden können. Es wäre schade, wenn an derartigen Formalien die Abnahme solcher Bücher in einem etwas größeren Leserkreis scheitern sollte. Diese allgemeinere Feststellung ist aber keine Kritik am Inhalt des Buches (70 EUR). Er liefert erneut einen überzeugenden Beweis, dass die mitteleuropäischen vegetationskundlichen Methoden und Grundlagen auch in ganz anderen Gebieten erfolgreich angewendet werden können.

Hartmut Dierschke

Tuexenia 25, 2005

Review: Phytocoenologia 35(4)/Dec. 2005 top ↑

Our knowledge of flora and vegetation of the Karakorum Mountains is still fragmentary. All the more welcome is the doctoral thesis of Einar Eberhardt that provides a conspectus of the vegetation of the upper Hunza catchment. A wealth of material is compiled and evaluated in this book. It is largely based on fieldwork of three expeditions to upper Hunza valley in 1994, 1998, and 2000, resulting in the completion of 414 relevés and the collection of more than 8.600 herbarium specimens. Additionally, the author evaluated data records of the Flora Karakorumensis project (DICKORÉ, unpubl.; DICKORÉ 1995) so that almost 11.900 species records (a complete floristic inventory) were included in various analyses aiming at a description and classification of spatial and structural patterns in the vegetation of the upper Hunza catchment. In order to broaden the synopsis of plant communities, the relevés were complemented by data from some phytosociological tables published so far for the Central Karakorum (Biafo) and Ladakh.

The tremendous account starts with a substantial landscape-ecological introduction to the study area providing thorough information on geology and tectonics, climate, climate history and glaciation, morphodynamics, landforms and soils, phytogeographical setting and vegetation cover as well as on socio-economic aspects and land use. The following chapter on material and methods indicates that the author felt obliged to combine traditional approaches in phytosociology and phytogeography with modern statistical techniques. E.g., altitudinal species turnovers were assessed with adequate statistical tools, phytosociological classification was cross-checked by detrended correspondence analysis (DCA), and the identification of differential species was supported by indicator species analysis (ISA).

Eberhardt presents the floristic results of his studies in an annotated checklist of vascular plants (App. 1), which is the third modern comprehensive annotated checklist in the region after DICKORÉ (1995) and DICKORÉ & NÜSSER (2000). The checklist contains a total number of 528 species belonging to 244 genera and 62 families, i.e., all vascular plants the author could collect in an area of about 3.500 km2. Each of the species is characterized according to horizontal and altitudinal distribution, life form, and phytogeographical element. The checklist data form the basis for the analyses at the beginning of the results chapter, starting with some impressive figures on phytodiversity, distribution of geo-elements and life form spectra. E.g., the elevational gradient of plant species richness shows an unimodal ('hump-shaped') curve peaking at mid-elevations of 3600-3900 m, thus basically corroborating vertical patterns in other arid temperate and subtropical mountains. Analyses of altitudinal species turnovers, which are very high throughout the study area, yielded the important result that vegetation belts cannot be delimited on the basis of altitudinal ranges of occurring species, i.e., physiognomically conspicuous altitudinal zonation on formation level is not reflected in species distributional limits. The treeline chapter refers almost exclusively to the upper treeline; the reader would expect here some more details on the hygrically controlled lower treeline.

The main part of the results' section is devoted to the synopsis of plant communities. 35 associations, 3 subassociations, and 2 variants are formally described and united, together with 7 other communities, into 6 alliances and 7 suballiances. The syntaxa are described with regard to physiognomy, distribution, floristic differentiation, syntaxonomical relationships, and ecology. Descriptions focus on floristic and syntaxonomical aspects, whereas remarks on ecology are sometimes rather brief. Unfortunately, the formal descriptions follow the outdated Code of Phytosociological Nomenclature of BARKMAN et al. (1986), and do not adhere to the presently effective International Code of Phytosociological Nomenclature (ICPN) (WEBER et al. 2000). E.g., nomenclatural types of the new syntaxa are not designated as 'holotypus'. Thus, syntaxa names are not validly published according to the ICPN. However, correct application of the ICPN could easily be realized in subsequent publications.

The author refrained from defining character species on grounds of unknown fidelity of the plant species in the study area. He used diagnostic species groups consisting of differential species to place syntaxa in his phytosociological scheme. Differential species were identified traditionally according to BERGMEIER et al. (1990) as well as by employing indicator species analysis (ISA), an increasingly popular numerical technique developed in zoological context (DUFRÊNE & LEGENDRE 1997). It remains unclear why both approaches were used and how they are related to each other since indicator species listed in the alliance synopsis figures are not identical with differential species listed in the diagnostic species groups. Also, the phytosociological tables (on CD-ROM) lack a clear designation of the status of species. A clear distinction of character and differential species would ease understanding, and would have seemingly been possible since the indicator value index provided by ISA is suitable for the determination of fidelity, the data base is very large and the study area is of considerable extent. So it is not quite comprehensible what the specific advantage if ISA is in the present study. Eberhardt justifies using ISA with replacing subjective elements of the Braun-Blanquet approach with statistical methods. However, selecting differential species according to the scheme of BERGMEIER et al. (1990), which is based on constancy (presence/absence), is a clearly understandable and reproducable procedure, even though it does not measure any statistical significance. A discussion of advantages and disadvantages of both approaches (e.g., CHYTRÝ et al. 2002) in the context of the present study would have been helpful.

Subsequent results chapters deal with the divergence of field layer composition between syntaxa with or without tree and shrub layers, remarks on the vegetation map of Batura valley (the core area of the study area), and distribution patterns of vegetation formations and single species in the wider region. It is very convincing how Eberhardt elaborates, by means of DCA's, the similarity of associations containing Artemisia brevifolia in the field layer, irrespective of the occurrence of junipers in the shrub and tree layers. This leads to the important conclusion that the current open vegetation originated from respective former forest communities due to grazing and wood-cutting. Results concerning regional distribution patterns of vascular plants, presented on dot maps for characteristic species (on CD-ROM), contain further valuable information. Vegetation scientists working in the region will welcome Eberhardt's clarification of the horizontal and vertical distribution of several juniper species (Juniperus semiglobosa, J. turkestanica, J. excelsa ssp. polycarpos), which are commonly confused in the literature, and the presented distribution patterns of several species of the genera Artemisia, Krascheninnikovia, or Kobresia.

In the discussion of his results, Eberhardt addresses structural and functional aspects of diversity, phytogeographical patterns, plant community issues, effects of land use, and includes also methodological considerations. He relates his findings to a whole array of currently discussed concepts in vegetation ecology, and, by doing so, occasionally leaves the frame of the present study, e.g., when discussing effects and functions of species richness. In chapter 5.3 he points out the limited distribution of lower-rank syntaxa and of differential species within the Karakorum. These findings together with the large data base and the large area covered let the reader again assume that a clearer differentiation of diagnostic species would have potentially been possible.

In summary, apart from some open questions this monograph is an impressive and valuable contribution to the knowledge of flora and vegetation of the Karakorum. Moreover, it is an indispensable reference publication for all vegetation scientists interested in flora and vegetation of western High Asia.

References

Barkman, J.J., Moravec, J. & Rauschert, S. (1986): Code of phytosociological nomenclature. 2nd edition. - Vegetatio 67: 145-195. Bergmeier, E., Härdtle, W., Mierwald, U., Nowak, B. & Peppler, C. (1990): Vorschläge zur syntaxonomischen Arbeitsweise in der Pflanzensoziologie. - Kieler Not. Pflanzenkde. Schleswig-Holst. Hamb. 20: 92-103. Chytrý, M., Tichý, L., Holt, J. & Botta-Dukát, Z. (2002): Determination of diagnostic species with statistical fidelity measures. - J. Veg. Sci. 13: 79-90. Dickoré, W.B. (1995): Systematische Revision und chorologische Analyse der Monocotyledoneae des Karakorum (Zentralasien, West-Tibet). - Stapfia 39, Linz. Dickoré, W.B. & Nüsser, M. (2000): Flora of Nanga Parbat (NW Himalaya, Pakistan). An annotated inventory of vascular plants with remarks on vegetation dynamics. - Englera 19, Berlin. Dufrêne, M. & Legendre, P. (1997): Species assemblages and indicator species: the need for a flexible asymmetrical approach. - Ecol. Monogr. 67: 345-366. Weber, H.E., Moravec, J. & Theurillat, J.P. (2000): International Code of Phytosociological Nomenclature. 3rd edition. - J. Veg. Sci. 11: 739-768.

Udo SCHICKHOFF, Hamburg

Phytocoenologia 35(4)/Dec. 2005

Contents top ↑


1 Introduction 11
1.1 Scope and aims of the study 12
1.2 The Karakorum Mountains: delimitation and division 14
1.3 History of exploration 15
2 The study area 19
2.1 Geology and tectonics 21
2.2 Present climate, climate history and glaciation 25
2.2.1 Present Climate 25
2.2.2 Climate and glaciation history 26
2.3 Morphodynamics, landforms and soils 31
2.4 Phytogeographical setting and vegetation cover 33
2.5 Socio-economic framework and land use 35
3 Material and Methods 40
3.1 Floristic sampling and additional data sources 40
3.2 Classification of phytogeographic elements and life forms 40
3.3 Measures for the assessment of altitudinal and latitudinal species
turnovers 42
3.4 Phytosociological sampling and table arrangement 44
3.5 Numerical techniques 47
3.5.1 Indicator Species Analysis (ISA) 47
3.5.2 Gradient analysis 48
3.6 Vegetation mapping 48
3.7 Soil parameters 49
3.8 Interviews on land use 49
4 Results 50
4.1 Flora and phytodiversity 50
4.1.1 Species numbers 50
4.1.2 Phytogeographic composition of the flora 52
4.1.2.1 Altitudinal distribution of phytogeographic elements 52
4.1.2.2 Latitudinal variation of the phytogeographical composition 55
4.1.3 Distribution of life form spectra 55
4.1.4 Three-dimensional species turnovers 58
4.2 Vegetation, belts and gradients 59
4.2.1 Species based delineation of vegetation belts 59
4.2.2 Delimitation of vegetation belts by species turnover rates 59
4.2.3 The treeline 61
4.2.4 Shift of species' upper and lower limits in the Batura Valley 63
4.2.5 Aspect divergences 64
4.3 Phytosociological synopsis 64
4.3.1 Alliance Piptathero gracile-Artemision brevifoliae all. nov. 66
4.3.1.1 Association Stipo orientalis-Krascheninnikovietum pungentis ass.
nov. 67
4.3.1.2 Suballiance Stipo himalaicae-Artemisienion brevifoliae suball.
nov. 70
4.3.1.3 Suballiance Koelerio cristatae-Artemisienion brevifoliae suball.
nov. 73
4.3.2 Alliance Poo attenuatae-Bistortion affinis all. nov. 83
4.3.2.1 Suballiance Carici nivalis-Bistortenion affinis suball. nov. 83
4.3.2.2 Suballiance Oxytropido humifusae-Bistortenion affinis suball. nov. 86
4.3.3 Alliance Juniperion semiglobosae all. nov. 91
4.3.3.1 Suballiance Hedysaro falconeri-Juniperenion semiglobosae suball.
nov. 93
4.3.3.2 Suballiance Ephedro gerardianae-Juniperenion semiglobosae suball.
nov. 95
4.3.4 Alliance Hippophaion rhamnoides all. nov. 99
4.3.4.1 Association Salici pycnostachyae-Hippophaetum rhamnoides ass. prov. 99
4.3.4.2 Association Calamagrostio pseudophragmites-Hippophaetum rhamnoides
ass. prov. 100
4.3.5 Alliance Salicion karelinii all. nov. 101
4.3.5.1 Association Carici nivalis-Salicetum karelinii ass. nov. 101
4.3.5.2 Suballiance Astragalo tecti-mundi-Salicenion karelinii suball. nov. 103
4.3.5.3 Gradient analysis of the alliance Salicion karelinii 105
4.3.6 Alliance Aconogonion tortuosi all. nov. 106
4.3.6.1 Association Linario odorae-Aconogonetum tortuosi ass. nov. 107
4.3.6.2 Association Elymo-Aconogonetum tortuosi ass. nov. 108
4.3.7 Associations of undefined alliances 109
4.3.7.1 Association Artemisio brevifoliae-Haloxyletum thomsonii ass. nov. 109
4.3.7.2 Betula jacquemontii communities 110
4.3.8 Communities with low abundance 112
4.3.8.1 Tamarix ramosissima scrub 112
4.3.8.2 Blysmus compressus flushes and wetland communities 113
4.3.8.3 Village pastures with Potentilla bifurca subsp. orientalis 115
4.4 Divergence of field layer composition between syntaxa with or
without tree and shrub layers 115
4.5 Vegetation Map of the Batura Valley 119
4.5.1 Settlements and place names 119
4.5.2 Mapping Units 122
4.5.3 Depiction guidelines of vegetation types 123
4.5.4 Explanation of the legend 123
4.5.4.1 Submontane desert and semi-desert dwarf scrub 123
4.5.4.2 Montane steppe, dwarf scrub and open forest 124
4.5.4.3 Subalpine steppe, mesophilous scrub and treeline forest 125
4.5.4.4 Alpine steppe and dwarf scrub 128
4.5.4.5 Upper alpine and subnival small turf spots and very scattered
herbs 128
4.5.4.6 Water surplus communities 129
4.5.4.7 Very sparsely vegetated to non-vegetated areas 131
4.6 Distribution of vegetation formations - the link to the climatic
gradient 131
4.7 The wider spatial scope: species distribution patterns in the
Karakorum 136
4.7.1 Desert species of lower altitudes 137
4.7.2 Species of montane and subalpine steppe, dwarf shrublands and
juniper forests 138
4.7.3 Species of riverside habitats, scree and rocks at medium altitudes 141
4.7.4 Species of moist treeline habitats 141
4.7.5 Species of high altitudes 143
4.7.6 Tibetan elements 143
4.7.7 Pamirian elements and high altitude Karakorum endemics 144
4.7.8 Vegetation belts: Sequence types and humidity regimes 144
4.8 Observations on land use effects 144
5 Discussion 147
5.1 Structural and functional aspects of diversity on various scales 147
5.1.1 Altitudinal limits and gradients reconsidered 147
5.1.2 Effects and functions of species richness 150
5.1.3 Are high mountain areas hotspots of biodiversity? 150
5.2 Phytogeographical patterns 153
5.3 Conclusions on the plant community level 154
5.3.1 Evaluation and scope of the syntaxonomic system 154
5.3.2 Vegetation and climate 157
5.3.3 Aspect and mesoclimate-related patterns 157
5.4 Effects of land use and the socio-economic transformation
processes 159
5.4.1 Effects of animal husbandry on vegetation cover 159
5.4.2 Livestock keeping on the decline? 160
5.4.3 Juniper forest and scrub and human impact 161
5.4.4 Anthropo-zoogenous versus climate change effects 162
5.5 Methodological considerations 162
5.5.1 Indicator Species Analysis (ISA) as a tool in phytosociology 162
5.5.2 The phytosociological system and gradient analyses 163
5.5.3 Do plant communities exist? 163
5.5.4 Species turnover along the altitudinal gradient - suitability of
ß-indices 164
6 Summary 166
7 Zusammenfassung 167
8 References 169
Abbreviations 185
Appendix 1 - An annotated checklist of vascular plants of the upper
Hunza catchment, N Pakistan 186
Appendix 2 - Species names used in relevés of Hartmann 206
Appendix 3 - Results of Shipley-Keddy analyses 210
Appendix 4 - Livestock census and grazing cycles 212
Appendix 5 - Phytosociological tables CD-ROM
Appendix 6 - Synoptic tables CD-ROM
Appendix 7 - Life-form spectra 217
Appendix 8 - Species distribution maps CD-ROM
Appendix 9 - Distribution of selected syntaxa with regard to altitude
and aspect 220