Introduction

Pangi Valley lies in the north-western extremity of Himachal Pradesh in the Chamba district. This is a cold arid region in the Trans Himalayas where rough terrain, scanty rainfall, harsh weather conditions and heavy snowfall are prominent features. Pangi Valley is a high altitudinal remote and  tribal area. It is bordered by two mountain ranges i.e. the Great Himalayan Range and the Pir Panjal Range and drained by river Chandrabhaga. Geographically the area lies between 32º 12’ 41” to 32º 47’ 59” N latitude and 76º 13’ 56”to 76º 47’ 48” E longitude with an  elevation ranges from 1800 to 6200 m (average elevation 4008 m), spreading over an area of 1600 sq km.

Pangi Valley can be approached by road from Chamba via Sach Pass, from Udaipur and from Jammu & Kashmir. The high altitudinal passes remain close during most of the months of a year (October- June) due to heavy snowfall cutting the Valley from rest of the country. Due to these geographical and climatic barriers Pangi has been remotely developed, culturally isolated and has preserved its biological diversity. Chandrabhaga (Chennab) flows in the south north direction cutting the Valley into two almost equal halves. The river on its due course through the Valley forms deep narrow gorges and Valleys with steep slopes. Number of small streams also called Nullah flow through the entire Valley and some are major tributaries of Chennab (Sechu Nalla, Luj Nalla, Twan Nalla, etc).

Pangi lies in the semi arid zone of inner Himalayas. This is a rain shadow area as high mountain peaks do not allow the heavy monsoon winds to reach the Valley making the climatic conditions harsh. Most of the precipitation here is in the form of snow fall along with avalanches. The temperature shows great fluctuation during the different months of the years. It takes a dip below mercury during the colder months of the year i.e. winters accompanied by strong winds. Summers are warmer with temperature rise of more than 25° C. Pangi Valley comes under cold and dry zone as per agro climatic conditions.

Pangi is sub divided into three major (Hudan, Sural, Saichu) and four minor Valleys. The region is remotely habituated with villages at far distance. The region is habituated mostly by Bhot and Pangwal tribal people. The higher altitudinal sub Valleys are called Bhatoris. Hinduism and Buddhism are the two major religions followed along with worship of local deities. Pangwali and Bhoti are the spoken languages.Saichu Tuan Nala Wild Life Sanctuary has been established in the Valley for the protection and conservation of wildlife. The Wildlife Sanctuary is spread over a wide area 390.29 square kilometres, with an altitudinal range of 2500 to 6000 meters including glaciers and high alpine grasslands. This is home to endangered snow leopards, . Ibex,himalayanthar, brown bear, black bear, musk deer, snow leopard. The birds include the Monal and Cheer pheasants, Himalayan western Tragopan.

Pangi Valley has been least studied for floristic studies (Watt 1881); for cytological studies which remained confined to dicot plants (Kumar et al., 2011; Rana et al., 2012, 2013; Singhal et al., 2009, 2011a, 2011b; Rana, 2015); for ethnobotanical studies (Rana et al. 2014; Dutt et al.2014). Bhattacharya and Uniyal (1980) reported very few species from Pangi locality and more stress was laid on Trilokinath region. Pangi was not included in Flora of Chamba District (Singh and Sharma, 2006) and there is no comprehensive account of vegetation from the study area. The study aims to present a general overview of the vegetation of this geographically isolated  important cold desert region of India.

Intensive field surveys and rapid sampling of vascular plants from different localities of Pangi Valley was done to explore the area from 2015-2016. A precise note was made on common plant species along with relevant details. List of important plants from the Pangi Valley with field number, name of species, family, locality, latitude, longitude, altitude,  and habitat and brief morphology notes is provided in table.  Species identification was done consultingregional floras Flora of British India(Hooker 1872-1897), Flora of Lahaul-Spiti (Aswal andMehrorta 1994), Flora of Cold Deserts of western Himalayas V-1 and V-2 (Murti 2001;  Shrivastava and Shukla 2015), Flora of Kullu (Dhaliwal and Sharma 1999),Flora of Himachal Pradesh (Chowdhery and Wadhwa 1984), Flora of Chamba (Singh and Sharma 2006). Further confirmation of the plant specimens has been done from Herbaria, Botanical Survey of India, Dehra Dun (BSD) and Forest Research Institute, Dehradun (DD). Photographs were taken for important plants.

Table 1: List of some selected plants from the Pangi Valley with field number, name of species, family, locality, latitude, longitude, altitude,  and habitat and brief morphology notes. 

Pangi is rich in terms of floral diversity and is home to some rare, endemic and endangered plant species. It is thickly forested at lower altitudes. Pinus, Cedrus, Picea, Abies, Taxus, Juniperus, Populus, Salix, Juglans, Betula and Acer are the dominant tree species in the Valley area. The higher altitudes above 4500 meters remain snow bound and are a glacier region. Herbaceous elements are most frequently found in the moist forest slopes near streams or the untouched areas such as subalpine and alpine grass lands or the Valley bottom i.e. deep gorges and river banks. The herbaceous flora is dominated by elements belonging to plant families Fabaceae, Asteraceae, Poaceae,Rosaceae etc.

The vegetational wealth of Pangi Valley can be categorized into the following types:

Himalayan Temperate Vegetation

This type of vegetation occurs in an altitudinal range of 2000–2,800 m. The vegetation comprises of Himalayan temperate type.Abies spectabilis, Acer pentapomicum, Cedrus deodara, Juniperus macropoda, Picea smithiana,Pinusgerardiana, Pinus wallichiana and Taxus wallichiana form the tree canopy. Populus ciliata and Salix viminalis are the broad leaf planted tree species. Herbs and shrubs are constituted by Allium humile, Alliaria officinalis, Arabidopsis thaliana, Berberis lycium, Caltha palustris, Daphne oleoides, Epilobium angustifolium, Geranium nepalense, Lonicera quinquelocularis, Prunus cornuta, Ribes orientale, R. nigrum, Rosa webbiana, Rubus saxatilis, R. foliolosus, R. macilentus, Sisymbrium orientale, Asplenium trichomanes and Sorbus foliosa.Many species of Artemisia such as Artemisia brevifolia, A. maritime and A. parviflora, A. vulgaris form dense scrubby vegetational cover over vast the slopes in the Valley.

Sub Alpine Vegetation

This type of vegetation occurs in an altitudinal range of 2,800–3,800 m. The major floral taxa found are Aconitum ferox, Allium humile, Angelica glauca, Aralia cachemirica, Arnebia benthamii, Aesculus indica, Berberis pseudoumbellata, B. jaeschkeana, Betula utilis, Bupleurum falcatum, Cardmine impatiens, C. macrophylla, Corylus jacquemontii,  Elymusdahuricus,  Ephedra gerardiana, Eritrichium canum, Erysimum melicentae, E. hieraciifolim, Dactylis glomerata, Geranium wallichianum, Impatiens glandulifera, Juglans regia, Malus baccata, Oxyriadigyna,  Pedicularispectinata,  Picrorhiza kurroa, Plantago depressa,  Polygonatum multiflorum, P. verticillatum, Potentilla atrosanguinea, Primula denticulata, P. macrophylla,, Prunus cornuta, Ranunculus laetus, Rhododendron campanulatum, Ribes orientale, Saussurea costus, S. auriculata, Tanacetum gracile, T. tomentosum, Thlapsi alpestreand Verbascum thapsus.

Alpine Vegetation

This type of vegetation starts from 3,800monwards, the vegetation is mainly dominated by speciesof Aconitum heterophyllum, A. rotundifolium, Agrostis vinealis,  Arnebia euchroma, Aquilegia pubiflora, Capparis himalayensis, Cassiope fastigiata, Cortia depressa, Delphinium cashmerianum, D. vestitum, Dracocephalum heterophyllum, Elymus nutans, E. dahuricus,  Fritillaria roylei, Heracleum wallichii, Myricaria squamosa, Corydalis meifolia, Geranium wallichianum, Impatiens brachycentra, Inula royleana,  Iris kumaonensis, Jurinea macrocephela, Meconopsis aculeata, Picrorhiza kurroa, Polygonum affine,  Primula macrophylla, Ranunculus hyperboreus, Rheum australe, R. moorcroftianum, R. spiciforme, Rhodiola imbricata, Rhododendron anthopogon, R. campanulatum, Saussurea graminifolia, S. obvallata, S. gossypiphora, Selinium tenuifolium and Trollius acaulis.

Figure 1a.k: A view of snow covered Sach Pass, 4,420 m a.sl.; b) Alpine slopes showing the vegetation in Harbi Dhar in the Sechu Tuan Wildlife sanctuary; c)   Click here to View figure

A view of Pine forest; c) Snow clad peaks and Betula (Bhojpatra) forest of slopes; d) A branch of Pinus gerardiana with female cone; e) Aconitum heterophyllum; f) Sinopodophyllum hexaandrum(Ban Kakri); g) Asplenium trichomanes; h) Vicia tenuifolia; i) Oxyria digyna; j) Verbascum thapsus

The entire Himalayan belt is known as treasure house for manymedicinal, aromatic, edible and aesthetic plants from time immemorial. Tribal people of Pangi Valley mostly depend on the wild plants as medicines for various ailments. Rana et al. (2014) documented 67 ethnomedicinally important plant species from the Valley whereas Dutt et al. (2014) have documented 45 species as ethno medicinally important. Some important medicinal plantsfound in the Valley like Aconitum heterophyllum (Patis, Ativisa), is a highly traded ayurvedic plant used as an anthelmintic, antiinflammatory, analgesic, astringent, antipyretic and febrifuge. The tubers are used in trade as a result the whole plant is uprooted.  As per ICUN it is a critically endangered species with decreasing population proposed to be included under CITES. This species is found growing both wild and cultivated in the Valley. Jurinea macrocephala (Dhup) is a commercially exploited plant used as incense. Picrorrhiza kurrooa locally called Karu or Kouris an endangered, ayurvedic plant used to cure asthma, diarrhea, jaundice and also used in stomach diseases (trade prohibited under CITES). Sinopodophyllum hexandrum (Ban Kakri) critically endangered plant found growing in the sub alpine and alpine region of Valley. The rhizome is of the plant yields a neurotoxin called podophyllin used in medicinal treatments. It is illegal to trade the plant in India under CITES (2014). Meconopsis aculeata(CR) another endangered medicinal plant used in tradition Tibetan medicine.

Pinus gerardiana, (chilgoza pine, noosa, neoza)is native to the north-western Himalayas, found in eastern Afghanistan, Pakistan, and northwest India (Kinnaur, Himachal Pradesh  and Luj area in Pangi Valley), is a an economically important species growing at elevations between 1800 and 3350 metres along with blue pine (Pinus wallichiana) and deodar (Cedrus deodara). The species is cultivated for its nutritious nuts. According to ICUN it is near endangered species with restricted naturaldistribution. The seeds of the plant are expensive and are a source of income to the local people here. Corylus jacquemontii is a Himalayan endemic taxa and its seed are eaten in the Valley. There is popular proverb in this context “Pangiki Thangi” highlighting the importance of the plant in the region.

Some of the important plants collected from the area in present study are Aconitum heterophyllum Wall. ex Royle, Artemisia maritima L.,  Aralia cachemirica Decne., Arceuthobium minutissimum Hook.f., Betula utilis D. Don, Bistorta affinis (D. Don) Greene, Cirsium wallichii DC., Dipsacus inermis Wall., Epilobium angustifolium L., Epilobium cylindricum D. Don, Euonymus fimbriatus Wall ex Roxb., Geranium nepalense Sweet, G. pratense L.,  Hyssopus officinalis L., Impatiens brachycentra Kar. & Kir., I. glandulifera Royle, Inula orientalis Lam., Juniperus communis L. J. semiglobosa Regel, J. indica Bertol., Juglans regia L., Prunus sp., Lespedeza juncea (L. f.) Pers., Lotus corniculatus L., Leptorhabdos parviflora (Benth.) Benth., Malus baccata (L.) Borkh. Meconopsis aculeata Royle, Medicago falcata L., Mentha longifolia Huds., Nepeta discolor Royle ex Benth., Oxytropis lapponica (Wahlenb.) Gay., Origanum vulgare L., Pedicularis punctata Decne., Picea smithiana (Wall.) Boiss. Plantago depressa Willd., Polygonatum verticillatum (L.) All. Polygonum plebeium R. Br., Polygonum polystachyum Wall. ex Meisn., Potentilla argyrophylla Wall. ex Lehm., P. cuneifolia Bertol., Pyrus lanata D. Don, Rosa webbiana Wall. ex Royle., Rosularia alpestris (Kar. & Kir.) Boriss., Salvia nubicola Wall. ex Sw., Sedum ewersii Ledeb., Senecio laetus Edgew., Sinopodophyllum hexandrum (Royle) T.S. Ying, Sorbaria tomentosa (Lindl.) Rehder, Spiraea canescens D. Don, Syringia emodi Wall. ex Royle, Taraxacum officinale L., Thymus linearis Benth., Trifolium repens L., Verbascum thapsus L. and Viburnum cotinifolium D. Don, etc. Some high alpine plants such as Delphinium sp., Juniperus sp., Meconopsis sp., Saussurea sp., and Rosa sp., have aesthetic value, used in religious placesand on other important occasions.

The grasslands are major source of feeding to the livestock here acting as very efficient soil binder and help prevent soil erosion in the region. Grasses like Bromus, Brachypodium, Phleum, Poa, Festuca, Digitaria, Stetaria, Elymus, Alopecurus, Phacelurus, Triticum, Avena, Hordeum and Arundo etc form a major soil cover in the region. These are very important component of the ecosystem in the Valley.However, activities such as entry of large livestock for grazing in summer to Valley from adjoining areas and dependence of people on wood as a fuel are the activities noted down during collection trip which may pose threat to local flora in a long term if not checked on time. Man and nature conflict is evident. There is a need of more efforts to study the fragile ecosystem of this region of North Western Himalaya. However, there are a few threats to note. i) unchecked deforestation and use of forest wood as a fuel, ii) grazing by the livestock from surrounding areas is goes unchecked, iii) ever increasing agriculture on slopes where ever possible and replacement of native forest by Salix and other broad leaf species poses a serious threat to local flora and fauna of the Valley.

The plants of the high altitudinal cold desert Valley have gone under a number of morphological, ecological and physiological adaptations to survive in the harsh climatic conditions prevailing in Valley. These are, development of a deep and strong extensive root system, underground modified stem i.e. rhizomes and bulbs, stunted growth with shrubby appearance, frost resistance, accumulation of starch grains in chloroplasts, vegetative reproduction with reduced sexual  life cycle and an efficient seed dispersal mechanism.

Pangi Valley is now set on path of development in terms of Infrastructure, economy, education, communication etc. However as the region is tribal and most of the local economy is directly or indirectly dependent on the natural resources, there is a near threat to the biological wealth of the region. There is need to put in more efforts for conservation and protection of biological resources in this magnificent Valley of inner Himalayas so that its cultural and biological heritage is conserved for the future generation.

Acknowledgement

Authors are greatly thankful to SERB-DST-Start up Research Grant (Young Scientists) (vide SERB sanction No. SB/YS/LS-182/2014 dated 08 September, 2015) for funding the study and to Director, Botanical Survey of India for providing necessary facilities.

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