Studies on Subalpine Forests of Hamta Pass Area in Himachal Pradesh, India with a Focus on Betula Utilis Populations

SPECIAL SECTION: Studies on subalpine forests of Hamta Pass area in Himachal Pradesh, India with a focus on Betula utilis populations Khashti Dasila1, S. S. Samant2,* and Anita Pandey3 1Centre for Environmental Assessment and Climate Change, G.B. Pant National Institute of Himalayan Environment, Kosi-Katarmal, Almora 263 643, India 2Himalayan Forest Research Institute, Conifer Campus, Panthaghati, Shimla 171 013, India 3Department of Biotechnology, Graphic Era (Deemed to be University), Bell Road, Clement Town, Dehradun 248 002, India biodiversity in the Himalayan ecosystems, which are rec- The present study was conducted in Hamta Pass area of Kullu district, Himachal Pradesh, India with a ognized for their provisioning, cultural, regulating and supporting services to both upland and lowland inhabi- focus on Betula utilis populations. Totally 16 popula- 4 tions of B. utilis representing four habitats and three tants . However, due to various anthropogenic and chang- aspects were studied. The maximum sites were ing climate scenarios, these ecosystems and the services represented by moist and moist, shaded habitats with provided by them are being severely affected, causing northwestern aspect. Totally 188 plant species loss of biodiversity and reduction in ecosystem services. representing trees, shrubs and herbs were recorded. Subalpine forests share the elements of high alpine and Acer acuminatum, Abies pindrow, Prunus cornuta and low temperate zones in the Himalaya, as they form a tran- Quercus semecarpifolia were the major associated spe- sition zone between temperate forest and alpine mea- cies of B. utilis in the subalpine zone of Hamta Pass. dows5. The biodiversity components (i.e. vegetation Based on importance value index five tree communi- structure, composition and function) of the subalpine and ties, namely A. acuminatum, A. pindrow, B. utilis, Q. semecarpifolia and B. utilis–P. cornuta mixed were alpine ecosystems are severely affected by heavy grazing, identified. Among the communities, total density of overexploitation of woody species for fuel by herdsmen trees, shrubs and herbs was recorded from 160 to 270, and non-timber forest products (NTFPs), including medi- 6 300 to 515 and 21 to 33 individuals m–2 respectively. cinal plants . The total basal area recorded was 6.94–42.10 m2 ha–1, The rapid geo-climatic variations are the basis of dif- species richness 15–127, and species diversity for trees ferent environmental gradients and result in vegetation 0.4–0.9, shrubs 0.0–2.1 and herbs 1.7–4.2. The density and diverse plant community types7. Habitat loss, frag- and regeneration (i.e. seedlings and saplings) of B. uti- mentation, overexploitation, alien species invasion and lis in most of the populations revealed that this species global climate change are the threats to biodiversity and will continue to grow in the area. However, continued the ecosystem8. These threats are also responsible for anthropogenic activities, climate change and other the decreasing trend of native species, upward shifting of factors may cause population depletion in the study area. species and the opportunity for proliferation of invasive and exotic species with low economic value9. Other than anthropogenic and climatic impacts, topographical factors Keywords: Betula utilis, regeneration, species diversity, (i.e. altitude, habitat and aspect) control the distribution species richness, subalpine forests, total basal area. patterns of vegetation in the Himalayan ecosystems10. In the current scenario, subalpine forests are the subject of Introduction interest for many researchers and are being studied for the impact of global climate change worldwide. THE unique topography, climatic conditions, diverse Betula utilis D. Don (bhojpatra or Himalayan silver habitats and large altitudinal range of the Indian Hima- birch) is a broadleaved, deciduous, ecologically and eco- laya Region (IHR) constitute an important part in global nomically important tree. It represents one of the domi- biodiversity hotspots1. The mountain ecosystem harbours nant species of the Himalayan treeline. The high freezing diverse biological communities and a high level of tolerance features enables this species to form a treeline 11 endemism2. The Northwestern Himalaya is irregular and in the Himalaya . This species is found in major associa- disturbed by valleys and plateaus with great floristic tion with Abies pindrow, Abies spectabilis, Quercus se- diversity due to altitudinal variations3. There is exorbitant mecarpifolia, Prunus cornuta, Acer acuminatum, Sorbus foliolosa, Pinus wallichiana and Rhododendron campa- *For correspondence. (e-mail: [email protected]) nulatum. The bark is the characteristic feature of B. utilis 872 CURRENT SCIENCE, VOL. 120, NO. 5, 10 MARCH 2021 NATIONAL MISSION ON HIMALAYAN STUDIES Figure 1. Map showing the sites of Betula utilis populations in Himachal Pradesh, India. due to its shining, reddish-white appearance having both Vegetation assessment in B. utilis forests ethnobotanical12,13 and phytochemical properties like anti-cancerous, anti-HIV, antioxidant, antimicrobial and Extensive and intensive field surveys were conducted anti-fertility activities14–16. during July and August 2018. For the sampling of floris- In general, systematic studies, i.e. qualitative and quan- tic diversity of B. utilis forests, each accessible habitat titative assessment of subalpine forests, including B. uti- and aspect was selected and assessed. Based on physical lis have been carried out by various workers17–33 in the characters and dominance of the vegetation, habitats were IHR. However, focused studies on B. utilis populations identified. Site characteristics, i.e. latitude, longitude, have not been carried out so far. Therefore, in view of the altitude, slope and aspect of each site representing B. uti- various anthropogenic pressures and changing climate lis populations were recorded with the help of global scenario, assessment of floristic diversity of the subalpine positioning system (GPS), Abney level and compass. For forests, including B. utilis populations becomes utmost quantitative assessment, a plot of 50 m × 50 m was laid important. randomly. Within this plot, trees, saplings and seedlings were sampled by laying ten quadrats of 10 m × 10 m; Materials and methods shrubs, 20 quadrats of 5 m × 5 m; and herbs, 20 quadrats of 1 m × 1 m (refs 33–35). Circumference at breast height Study area (cbh), i.e. 1.37 m and diameter at 10 cm from the base for each tree and seedling were recorded for considering The present study was conducted in Hamta Pass area of individuals as trees (cbh ≥ 31.5 cm), saplings (cbh 10.5– Northwestern Himalaya of Kullu district, Himachal Pra- 31.4 cm) and seedlings (cbh < 10.5 cm). Shrubs were desh, India (Figure 1). The subalpine zone in the present considered as woody species having several branches study area is dominated by broadleaved deciduous species arising from their base, and herbs were considered as (i.e. Q. semecarpifolia, P. cornuta, A. Acuminatum, S. fo- those species having aerial parts surviving for one season, liolosa, Corylus jacquemontii and B. utilis) and evergreen though their underground parts, i.e. roots/rhizomes/bulbs, coniferous species (i.e. A. pindrow, A. spectabilis and P. etc. may remain alive during other seasons. From each wallichiana). The dominant shrub species are Rhododen- site, samples of each species were collected and identi- dron campanulatum, Rhododendron anthopogon, Salix fied with the help of local and regional flora17–21. denticulata, Rosa macrophylla, Rosa sericea, Smilax vagi- The data collected during field surveys were analysed nata, Spiraea bella, Juniperus indica and Lonicera spp. in MS-Excel following standard ecological methods36–38. CURRENT SCIENCE, VOL. 120, NO. 5, 10 MARCH 2021 873 SPECIAL SECTION: Table 1. Site/habitat characteristics of Betula utilis populations in Hamta Pass area, Himachal Pradesh, India Site Altitude (m) Latitude (N) Longitude (E) Habitat Slope (°) Aspect Community 1 3057 32°12′52.32″ 77°14′18.42″ Moist 50 NW BU 2 3109 32°13′42.54″ 77°14′08.82″ Bouldery 65 NW AP 3 3150 32°14′56.94″ 77°14′41.16″ Shady moist 55 SW AP 4 3155 32°15′03.60″ 77°14′44.22″ Moist 55 NW BU 5 3171 32°12′55.14″ 77°14′30.72″ Moist 60 NW BU 6 3173 32°15′46.44″ 77°15′05.94″ Shady moist 40 W BU 7 3190 32°15′41.46″ 77°14′59.40″ Moist 30 NW QS 8 3230 32°14′58.92″ 77°14′45.84″ Moist 60 W AA 9 3258 32°15′52.02″ 77°15′13.50″ Moist 40 NW BU 10 3310 32°13′45.00″ 77°14′20.94″ Shady moist 50 W QS 11 3317 32°13′02.58″ 77°14′54.78″ Moist 35 NW BU 12 3364 32°13′18.60″ 77°14′55.74″ Shady moist 40 SW BU 13 3411 32°15′46.26″ 77°15′25.08″ Rocky 50 W BU 14 3505 32°13′45.78″ 77°14′35.34″ Bouldery 60 W BU 15 3753 32°16′01.50″ 77°15′06.54″ Rocky 40 NW BU 16 3760 32°15′57.06″ 77°15′01.92″ Rocky 30 SW BU–PC BU, Betula utilis; AP, Abies pindrow; QS, Quercus semecarpifolia; AA, Acer acuminatum; PC, Prunus cornuta. On the basis of importance value index (IVI), different among altitude and ecological parameters. Pearson corre- communities were identified. Thereafter, data from dif- lation coefficient was calculated between various ecological ferent populations were pooled to calculate community parameters and soil parameters using STATISTICA-8. averages in terms of density, total basal area (TBA) and Shannon–Wiener information index of species diversity Results and discussion (H′)39. The total count of species was considered as species richness. The diameter size class was employed to Site and habitat characteristics develop the population structure of tree species. Ten ran- dom size classes (<10.5 cm for seedlings, 10.5–31.4 cm Totally 16 populations of B. utilis were assessed from for saplings, 31.5–41.5, 41.6–51.5, 51.6–61.5, 61.6–71.5, different accessible aspects and habitats in the subalpine 71.6–81.5, 91.6–100.5 and >100 cm) of individuals tree zone for status and distribution pattern.

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