Phytodiversity and growth form in relation to altitudinal gradient in the Central Himalayan (Kumaun) region of India (original) (raw)
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Plant richness pattern in an elevation gradient in the Eastern Himalaya
Biodiversity and Conservation, 2019
In spite of many theoretical explanations, the plant richness pattern along the mountain elevation gradient is still debatable. Here we considered East district of Sikkim state in the Eastern Himalaya to study plant richness pattern of vascular plants along an elevation gradient of 500–3300 m at 100, 200 and 300 m elevation steps. The study evaluates species area relationships along the elevation gradient, spread over four major forest types i.e., low (tropical to sub-tropical, up to 900 m), middle (subtropical, 750–1500 m), upper (wet temperate, 1500–2700 m) and Rhododendron-Conifer Zone (cold temperate/sub-alpine, 2700– 3600 m) with 664 species from 367 genera and 131 families. Pteridium aquilinum was found to be the most diverse species occurring in all 28-elevation steps along 500–3300 m, followed by Polystichum lentum, Polygonum runcinatum and Nephrolepis cordifolia those occured in 23 elevation steps. In general, a hump shaped pattern was observed for plant richness of all life forms along the elevation gradient. The peaks became prominent, with the increase in scale of extent from 100 m (R2=50%) to 300 m (R2=78%) through 200 m (R2=55%) elevation steps, using 2nd order polynomial ftting. The reduction in tree height and richness was noticed beyond 2300 m allowing dominance of herbs owing to climatic constraints. Using generalized additive model, temperature could explain the maximum deviance of>47%. Soil explained 36.4% deviance, followed by precipitation (21.6% deviance) in the plant richness. However, the ecotone efect of diferent forest types explained the mid-elevation peaks in plant richness more prominently than the geographic area availability. Further, inclusion of disturbance and biotic interactions may improve ecological understandings on the plant richness pattern along the elevation gradient.
Influence of altitude on the distribution pattern of flora in a protected area of Western Himalaya
Acta Ecologica Sinica, 2020
Introduction: Distribution pattern and diversity of flora was compared along an altitudinal gradient using the stratified random sampling design for identifying major plant communities of Kedarnath Wildlife Sanctuary of Garhwal Himalaya, India. The reconnaissance of flora is presented, along with the analysis of the distribution of species, genera, and families within five (5) altitudinal zones. Kedarnath Wildlife Sanctuary which is situated in the Indian Himalayas harbours a rich variety of flora and fauna. The Himalayas are recognized for diverse vegetation distributed over a wide range of topographical conditions. Results: The analysis of diversity within five (5) altitudinal zones was carried out and a total of 324 plant species, representing 219 genera belonging to 92 families, were found. The dominant family was Asteraceae; the codominant family was Rosaceae, followed by Lamiaceae and Ranunculaceae. Eight (8) families were observed in all the altitudinal zones, while forty (40) families were observed in a single altitudinal zone, and the remaining forty-four (44) families were found in more than one (1) altitudinal zone. Most of the tree species were contagiously distributed, but a few of them were randomly distributed in all the altitudinal zones. The shrubs and herbs were contagiously distributed in all the altitudinal zones. The correlation analysis (P b 0.05) between altitude and number of species showed that altitude is negatively correlated with tree (r = −0.96), shrub (r = −0.61), and herb species (r = −0.20). As per the cluster analysis of tree layer, altitudinal zone-III (2450-2650 m) and altitudinal zone-IV (2900-3100 m) were found most similar. Altitudinal zone-V (3350-3550 m) was found to be dissimilar from the other zones for herbs. Conclusions: Although species composition varies with altitude, but there is a complex relationship between species richness and altitudinal gradient. A decreasing pattern in both species richness and family richness for trees, shrubs and herbs, was recorded with increasing altitude. The predominant factors underlying this variability in plant species and biogeography appear to be climatic and specific to each taxonomic group.
Paistan Journal of Botany, 2013
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.
Does Altitude Effect on Species Composition and Diversity on Himalayan Rangeland?
Himalayan Journal of Science and Technology
Himalayan rangelands have diverse floristic composition and important ecological services. The floristic diversity and composition play an important role in grassland ecosystem regulation. It is different in altitudinal gradient due to grazing intensity, climatic condition and topography. To reveal the vegetation composition values, this work was conducted on August and September 2011 in Tinjure-Milke mountain ridge, Guphapokhari, Nepal. In the present study we have described the impact of altitude on the species richness, species diversity and dispersion behavior of different plants (grasses) in Himalayan rangeland. The values of community indices were observed to be: RD (0.09 to 49.57), RF (3.57 to 14.71), RA (0.23 to 47.59), IVI (3.89 to 111.87), Shannan-Wiener diversity index (1.09 to 2.23) and species diversity evenness (0.12 to 0.19) at the study area, MilkeJaljale, eastern Nepal. Similarly, Species richness (R) value of 8.87 to 11.86 and Simpson dominant index value of 0.12 t...
In the present study, primarily we aim to check the prediction of species richness pattern with elevation gradient and compare the empirical study with regional pattern and regressed it with different environmental parameter as well. The sampling method was designed to include all the habitat types and vegetation. Latitude, longitude, altitude, and aspect were recorded for each plot. The total vascular plants along with the life forms were regressed against the altitude. The regression was also done between species richness and different environmental parameters. A Generalized Linear Model (GLM) with a quasi-poisson error of distribution was used to elucidate the pattern of species richness. A total of 199 vascular plant species were recorded of which 145 species were herbs, 21 trees and 33 shrubs. Species richness of total vascular plants and all life forms showed a unimodal pattern with altitude. An empirical study coincides with the regional study forming a peak at mid altitude but no plateau was observed in our study. Despite the pattern, regional studies showed a mid altitude peak at 1500 m asl but our study had a peak at an altitude of 3500 m asl. This study clearly shows the differences in pattern of species richness between the regional scale and local scale which is due to the differences in sampling strategy and data gathering methods.
Community structure and composition are important factors affecting diversity patterns in plant communities. Pertinently, species diversity along altitudinal and latitudinal gradient differs in different layers at different scales. Thirteen community groups characterized by different dominants in the tree layer were distinguished. These include Himalayan subtropical scrub (580-850 m asl), Northern dry mixed deciduous forest (600-1100 m asl), Himalayan subtropical pine forest (780-1450 m asl), Lyonia / Alnus / Rhododendron forest (1250-1500 m asl), Mixed Oak forest (1300-2150 m asl), Rhododendron - Oak mixed forest (1600-2200 m asl), Pine / Oak mixed forest (1400-1750 m asl), Pure Cedrus deodara forest (1450-1700 m asl), Taxus wallichiana forest (2000-2580 masl), Deodar / blue pine mixed forest (1900-2600 m asl), Fir / Spruce mixed forest (2700-3250 m asl), pure Betula forest (3100-3500 m asl), and alpine scrub (above 3500 m asl). Distribution of importance values of dominants explicitly indicated a vertical pattern of these forest types. The sub-tropical and temperate elements of vegetation reveal predominance of closed canopy forests, wherein the sub-tropical tree species outnumber the temperate tree flora. The community analysis was performed using stratified random sampling involving 0.01 % of the total area for each community. The pattern of plant diversity as observed by the values of species richness and diversity indices show a decreasing trend from lower to higher altitudes. The study suggests that distribution and species richness are largely regulated by physiography (altitude, latitude, slope, aspect etc.) and climatic factors.
SPECIES DIVERSITY AND PHYTO-CLIMATIC GRADIENT OF A MONTANE ECOSYSTEM IN THE KARAKORUM RANGE
Analyzing species diversity and understanding phyto-climatic gradient is crucial for proper management of montane ecosystem. The study site is located in the Karakoram Mountains, Baltistan (Northern Pakistan), covering an area of 2750 Km². It is situated on the right bank of the River Indus in the Central Karakorum Mountains at an elevation range of 2000 to 6000 m at sea level. On the basis of change in topography, elevation and climate study area was classified into four Vegetation Zones viz. dry zone, agro-forestry zone, Sub-alpine zone and Alpine zone. A total of 180 species of vascular plants representing 139 genera and 53 families were collected with generic index of 1.2. Twenty four families were represented by single species. and family Asteraceae was dominant family including 36 species followed by families Papilionaceae, Polygonaceae, Rosaceaeand Chenopodiaceae representative of 11, 10, 10 and 8 species respectively. Artemisia (7 species), Chenopodium (4), Astragalus (4) and Geranium (3) were identified as leading genera. Habit wise perennial herbs prevailed with 113 species followed by annuals (41 species), shrubs (18), biennials (3) and trees (3).In biological spectrum, the area is dominated by 46% of Hemicryptophytes (84 species) followed by 21% therophytes (39), 11% Chamaephytes (21), 10% Nanophanerophytes (18),10% Geophytes (14) and 2% Mega-phanerophytes (3). The altitudinal gradient of species showed that the species richness declines with increase in elevation from sea level. Most of the species found in the middle elevations (2700-3300m) and a sharp decrease were observed at high elevation (above 3900m). Agricultural encroachment, grazing, blasts for gemstones; rock drifting and land sliding were common and severe natural and anthropogenic threats. These and many other threats to the available vegetation urge for more precise botanical explorations and prompt conservatory management in the scenario of national and global interest in these fragile ecosystems.
Journal of Tropical Ecology
Tropical montane systems are characterized by a high plant species diversity and complex environmental gradients. Climate warming may force species to track suitable climatic conditions and shift their distribution upward, which may be particularly problematic for species with narrow elevational ranges. To better understand the fate of montane plant species in the face of climate change, we evaluated a) which environmental factors best predict the distribution of 277 plant species along the Himalayan elevational gradient in Nepal, and b) whether species elevational ranges increase with increasing elevation. To this end, we developed ecological niche models using MaxEnt by combining species survey and presence data with 19 environmental predictors. Key environmental factors that best predicted the distribution of Himalayan plant species were mean annual temperature (for 54.5% of the species) followed by soil clay content (10.2%) and slope (9.4%). Although temperature is the best pred...