PJB-2013-348
PHYTO-CLIMATIC GRADIENT OF VEGETATION AND HABITAT SPECIFICITY IN THE HIGH ELEVATION WESTERN HIMALAYAS
SHUJAUL MULK KHAN1, 4, *, SUE PAGE2, HABIB AHMAD3, ZAHIDULLAH5, HAMAYUN SHAHEEN5, MUSHTAQ AHAMD5AND DAVID HARPER4, *
Abstract
Phyto-climatic gradient and ecological indicators can be used to understand the requirements, long term management and conservation strategies of natural habitats and species. For this purpose phytosociological attributes were measured using quadrats along transects on different slope aspects across an elevation range of 2450-4400 m. The 198 recorded plant species were placed in five Raunkiaer life form classes among which the Hemicryptophytes (51%) dominate the flora of the study area followed by Phanerophytes and Cryptophytes (Geophytes) with 15 and 13% dominance respectively. Therophytes and Chamaephytes are represented by smaller numbers (12 & 10% each). The phyto-climatic gradient of the vegetation was evaluated using Detrended Correspondence Analysis (DCA) and Canonical Correspondence Analysis (CCA). Phyto-climatic relationships show that Phanerophytes especially tree species are widely distributed on northern aspect slopes whilst shrubs are more dominant on southern aspect slopes. Woody plants are dominant at lower altitudes (2450-2800 m), with a much smaller proportion occurring at middle elevations (2800-3300 m) whilst higher (3300-3900 m) and highest elevations (3900-4400 m) are dominated mainly by hemi-cryptophytes and cryptophytes. Our findings further elucidate that vegetation changes gradually from moist-cool temperate Phanerophytic and Chamaephytic elements to dry-cold subalpine and alpine herbaceous Cryptophytic and Hemi-cryptophytic vegetation in the upper elevations. Assessment of life forms and ecological gradient provide a basis for more extensive conservation studies on biodiversity in mountain ecosystems. Our findings further advocate that the Naran Valley appears to be at a transitional floristic position bridging the contrasting moist and dry temperate zones of the Sino-Japanese and Irano-Turanian floristic regions.
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