Pbv12n1 73.Pdf

A PRELIMINARY SURVEY OF THE POST-GLACIAL VEGETATIONAL HISTORY OF THE KASHMIR VALLEY GURDIP SINGH Birbnl Sahni Institute of Palaeobotany, LucknolV ABSTRACT course of the main river Jhelum. The latter, along with its large number of tributaries, Pollen-analytical investigations of Post-glacial has shaped the presen t relief of this area, deposits from four sites (Toshmaidan, Braman, Walanwar and Damamsar) distributed over the resulting in the extensive dissection of the Kashmir Valley slopes of the Pirpanjal Range Karewa beds and causing the formation of constitute the subject matter of this paper. The terraces and lowland swampy areas and study reveals for the first time the Post-glacial lakes such as Wular, Manasbal, Anchar, vegetatio'lal history of the Kashmir Valley especially with regard to Post-glacial climatic alterations, Dal, etc. biotic influences on vegetational development and The Pir Panjal Range - a sub-Himalayan' the phytogeography of the region. mountain - rises abruptly from the plains The sequence is divisible into eight stages. The and forms'a major barrier between the forest history began with an open vegetation with conifer woods consisting of blue pine (P.inus w(,lli Panjab and the Kashmir Valley proper. r.hiana) and cedar (C.dn,s deod(l1'a). During the It rises to an average altitude of ca. 3,750 m. ensuing period a set of warmtb and moisture de above sea level with peaks touching as high manding broad-leaved elements such as oaks, alder, as ca. 4,660 m. The region a50ve ca. birch (Betula alnoides). elm, walnut, maple and Rhus immigrated indicating a climatic trend towards 3,600 m. in particular has the characteristic increasing warmth. Later, forests comprised domi appearance of a once glaciated area with a nantlv of broacl-Ieaved elements estahlished them large number of high altitude lakes filling selves marking thereby a phase of optimum warmth the old glacially scoured bowls and cirques. which in turn was followed by the re-establishment of conifers, a fact pointing towards the return of Climate. - The present-day climate of the colder conditions. The conifer woods were mainly Kashmir Valley is considerably influenced comprised of Pinus walliehia'lla and Abies webbiana. by the position of the Pir Panjal Range. Some of the cha.nges in the vegetational sequence This is shqwn by the fact that although the are also believed to have been induced by man's direct or indirect influence on vegetation. Evidence region south of this range enjoys a sub of maize cultivation in the past has also been tropical climate, the corresponding area at brought out. The bearing of this work on the similar altitude to the north (the Kashmir history of some of the mesophytic elements such Valley) has a temperate climate. However, as Que·reus spp., Ahms and Betula alnoides, which in the summit region of the Pir Panjal Range, are today absent from the Kashmir Valley, is also discussed. the climate, leaving aside the rainfall, is more or less of the same (cold arctic' type on either side, though the snow melts much INTRODUCTION earlier on the southern slopes than on the corresponding northern side during the EOGRAPHY - The Kashmir valley summer months. The full impact of the (approximately 73" 55' to 75° 35' E monsoon in the entire Kashmir region occurs G and 33° 25' to 34° 40' N; TEXT-FIG. 1) in July when stations such as Jammu, record lies towards the north-west of peninsular rainfall as high as 305. mm. whereas Gulmarg India. It is bounded on the north and east on the lee side of the Pir Panjal Range, by the high mountains of the main Hima records barely 101 mm. and Srinagar even layan Range, whereas, towards the south less (58 mm.) for the same period (TEXT and southwest, the Pir Panjal Range divides FIG. 2). These facts reflect markedly the it from the plains of Jammu and Poonch. effectiveness of the Pir Panjal Range as a The valley is boat-shaped, with its floor barrier between the two sides of the range. lying at an altitude of about 1,560 m. and The humidity reaches its climax in the extends over an area of about 5,200 sq. km. winter months in the Kashmir Valley, a fact Its deepest part lies along the foot of the which is caused by the fall of mild winter Main Himalayas and is marked by the showers in the area. The temperature rises n 74 THE P\L\EOBOL\~IST 36°N 73 7S 76 36°N 3S ).....~. ,0 ~ ..<)/..0 <'..iO ~..A ~". (C' ~ 'Yc. 'Y 33 l' ~. Chitto- C h cznab "9 ~~NGt. ..... SCALE :1=32rniks Gujrat • , , 74 ... ,75 76 TEXT-FIG. 1 - :Vlap showing Jammu & l<ashrnir (Based on Sahni, 1936, Fig. 1). as high as 38°C during summer in the plains NELLI, 1913; DE TERRA, 1938 and W ADIA, south of the Pir Panjal Range while it 1938). 0 rarely exceeds 3l 0 and 21 C at Srinagar and Palaeoecological studies in this region Gulmarg respectively. The winds in the have so far been confined to early Quater Kashmir Valley blow from the northwest, nary deposits (GODWIN AUSTEN, 1864; west or southeast and storm or cyclonic MIDDLEMISS, 1911; VV ADlt\, 1919; DE TERRA, conditions arise at the height of the monsoon 1932; WODEHOUSE, 1935; SAHNI, 1936; in July.. IYENGAR and SUBRAMANAYAN (.1943); PURl, Previous War!? - The Kashmir Valley is 1943-53; N Am., 1960), while Post-glacial one of the fev" areas in the Indian subconti deposits have remained untouched. Never nent where unmistakable records of the theless, from the geophysical and historical Pleistocene' Glacial Age' have been located records in Northwest India, De Terra and and studied in detail. Four main oscilla Hutchinson (1936) inferred the first probable tions of climate have been detected (DAI- Post-glacial sequence of climate, in the alter- GlJRDIP ST:-iGH - POST-GL.-\CIAL VEGET:\TIO~:\L HISTORY OF KASHMIR VALLEY 7S so 0 +1----.-:J=-------.:..F_-:.-M----.-:-----.:..A_--:-M~~J _ ___=_..J_--:-A...:.-.-----=S:._--=--O I\J D 400 f' ~- JOO // -" / " 200 ,'" 1001 . _. omm --=-=-=---- -- __ :------.c r-------" ~-:""'''', . - ' --- -- -- - - --- - -- --- -- RAINFALL ;00 -------::::-::;-:==:::~~::-=:---------- 801 . --- _--:-. .:-::.----:.- ~_. 60 -' " ...... --- 40 ~-- - 20 0 ...'--------- · _ 1. HUMIDITY 45° J5~ ------------ ... ----- --- ... -"'-- ... 25° ------ 1S° S° -S° _15°.....1 . CO TEMPERATURE SRINAGAR (18'11-1'140) JAMMU (1'101-1'140) CULMARG (1'111- \'140) TEXT-FIG. 2 -- Normal monthlv values of rainfall, reI. humidity and temperature in Kashmir (data by courtsey of I ndia Meteorological Department). nation of wet and dry periods and also re sides these, very little information is avail corded the existence of two Post-glacial able on the large number of Post-glacial 'Ice Advances', i.e., the Fifth and Sixth. deposits in lakes, swamps and mires occuring The moraines of the latter have been shown in the Kashmir Valley. Detailed study of to lie in an intermediate position between these sites comprising their ecology, floris the terminal moraines of the Fourth Glacia tics, nature of their sediments and other tion and the recen t moraines of the existing aspects in relation to pollen-analytical glaciers. investigations have yet to be carried out. De Terra and Hutchinson (1936) and De Mukerji (1921, 1925), in a preliminary Terra and Paterson (1939) have mentioned account has provided some information of the occurrence of Post-glacial deposits in the the hydrarch succession at Dal lake (ca. Kashmir Valley in the form of river terraces, 1,560 m.). He maintained that the plant yellow loess and morainic deposits but be- communities of this lake culminate in diffe- 76 THE PAL.<\EOBOTANIST rent' climax' of vegetation in different loca as described by' Mukerji (1921,1925). The lities but that in general the plant succession aquatic plants are regularly harvested by is as follows: In the ' Aquatic Formation' the inhabitants for the purpose of building plants such as species of Potamogeton, Hydl·il floating arable plots within the lakes. la, Myriophyllum etc. dominate and consti Post-glacial peat is formed in the Kashmir tute 'Deep water Association: with Chara Valley in places which can best be termed forming a dense mat on the bed. The mires1 They are formed on the valley , Floating-leaf' or 'Shallow water Associa slopes of the Pir Panjal Range and the Main tion' is dominated by Trapa, Nelumbium, Himalayas at heights between ca. 1,600 m. Nymphaea, Eurale ferox etc. Further the and 3,500 m. The mires, which are distri , Reed-swamp Association' is dominated by buted within the forest belts, an! generally TYPha, Sparganium, Carex etc. and these small and usually measure between 10 and plants along with 'Floating-leaf Associa 30 m. in length and breadth. They are tion " form various Consocies. In the generally formed on gentle slopes, either 'Marsh Formation', Ranunculus aquatilis, singly or in successions of two or three Callitriche, Hippuris, Ceratophyllum, Juncus situated one above the other on more or less etc. constitute the' Herbaceous Marsh Asso flat terraces. On the valley slopes of the ciation ' and willows, sometimes poplars etc. Pir Panjal Range which are covered over by along with an undergrowth of perennial a thick sequence of Pleistocene Karewa clay herbs form 'Salicetum Association' and beds, the mires sometimes assume a quag , demp' land. The 'Meadow Formation' mire type of developmeht and peat is rarely is dominated by grasses and perennial herbs. developed. Both the ' demp land' and meadow stage' The mires occurring in the large number are converted into arable land by man. of glacially scoured basins occupying open The meadow stage on the eastern and patches within the forest or above the tree southern shores of .the Dal Lake is succeeded line have been occasionally found to accumu by' Gravel-slide' Formation or ' Xerophytic late fairly thick deposits of peat or organic Bushland' Formation - constituted by mud.

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