Modern pollen assemblages from Hamtah and Chhatru glaciers, Lahaul-Spiti, India: Implications for pollen–vegetation relationship in an alpine arid region of western Himalaya

Kar, Ratan; Bajpai, Ruchika; Singh, Ayushi

doi:10.1016/j.quaint.2015.02.047

Cited by 26 publications

(6 citation statements)

References 27 publications

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“…The comprehensive effect of these factors is an important reason for the change in vegetation cover in this basin. Previous studies of the influence of climate factors on the FVC have shown that precipitation is the primary influence on the FVC and that significant changes occur around glaciers, snow cover and lakes in mountainous regions [ 67 , 68 , 69 , 70 ]. We found that the higher the annual precipitation, the higher the vegetation coverage in the Urumqi River basin.…”

Section: Discussionmentioning

confidence: 99%

Spatiotemporal Evolution and Driving Forces of Vegetation Cover in the Urumqi River Basin

Mamattursun

Han

Ablikim

et al. 2022

IJERPH

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It is important to determine long-term changes in vegetation cover, and the associated driving forces, to better understand the natural and human-induced factors affecting vegetation growth. We calculated the fractional vegetation coverage (FVC) of the Urumqi River basin and selected seven natural factors (the clay and sand contents of surface soils, elevation, aspect, slope, precipitation and temperature) and one human factor (land use type). We then used the Sen–Man–Kendall method to calculate the changing trend of the FVC from 2000 to 2020. We used the optimal parameters-based geographical detector (OPGD) model to quantitatively analyze the influence of each factor on the change in vegetation coverage in the basin. The FVC of the Urumqi River basin fluctuated from 2000 to 2020, with average values between 0.22 and 0.33. The areas with no and low vegetation coverage accounted for two-thirds of the total area, whereas the areas with a medium, medium–high and high FVC accounted for one-third of the total area. The upper reaches of the river basin are glacial and forest areas with no vegetation coverage and a high FVC. The middle reaches are concentrated in areas of urban construction with a medium FVC. The lower reaches are in unstable farmland with a medium and high FVC and deserts with a low FVC and no vegetation. From the perspective of the change trend, the areas with an improved FVC accounted for 62.54% of the basin, stable areas accounted for 5.66% and degraded areas accounted for 31.8%. The FVC showed an increasing trend in the study area. The improvement was mainly in the areas of urban construction and desert. Degradation occurred in the high-elevation areas, whereas the transitional zone was unchanged. The analysis of driving forces showed that the human factor explained more of the changes in the FVC than the natural factors in the order: land use type (0.244) > temperature (0.216) > elevation (0.205) > soil clay content (0.172) > precipitation (0.163) > soil sand content (0.138) > slope (0.059) > aspect (0.014). Apart from aspect, the explanatory power (Q value) of the interaction of each factor was higher than that of the single factor. Risk detection showed that each factor had an interval in which the change in the FVC was inhibited or promoted. The optimum elevation interval of the study area was 1300–2700 m and the greatest inhibition of the FVC was seen above 3540 m. Too much or too little precipitation inhibited vegetation coverage.

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Section: Discussionmentioning

confidence: 99%

Spatiotemporal Evolution and Driving Forces of Vegetation Cover in the Urumqi River Basin

Mamattursun

Han

Ablikim

et al. 2022

IJERPH

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“…The palynological data show that Pinus is the major element of the pollen-rain and the pollen assemblages of all the three vegetation zones show an overwhelming dominance of Pinus pollen over all the other arboreal and non-arboreal taxa. The primary reason for the abundance of Pinus is its bountiful pollen production, excellent pollen dispersal efficiency and good preservation potential in the sediments (Andersen, 1970; Bajpai and Kar, 2018; Ertl et al, 2012; Kar et al, 2015; Pidek et al, 2010; Quamar et al, 2018). The high concentration of sporopollenin, the most chemically inert biological polymer, in the outer wall (exine) of Pinus pollen, makes it resistant towards oxidation and degradation (Havinga, 1984), facilitating the good preservation of Pinus pollen in the sediments.…”

Section: Discussionmentioning

confidence: 99%

Modern pollen–vegetation relationships along an altitudinal transect in the Western Higher Himalaya, India: Palaeoclimatic and anthropogenic implications

Mishra¹,

Mohanty

Ghosh³

et al. 2022

The Holocene

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Palynology is one of the most reliable tools for the reconstruction of past vegetation and climate and modern pollen analogues are important for the calibration of fossil pollen assemblages. The present study analyses the pollen–vegetation relationships along a steep altitudinal gradient (2700–3680 m), in the western Higher Himalayan region. On the basis of altitude, three vegetation zones were demarcated: Zone I (2700–3100 m) is composed of mixed-temperate forest vegetation, dominated by Quercus semecarpifolia and Rhododendron arboreum; Zone II (3100–3250 m) is marked by sub-alpine forest vegetation, characterised by R. campanulatum and R. barbatum, along with Abies spectabilis and Q. semecarpifolia; Zone III (3250–3680 m) is above the tree-line (3250 m) and represented by alpine-scrub and meadows. Thirty-five surface soil samples (twenty, seven and eight from each zone, respectively) were analysed along the altitudinal transect to decode the representation of the extant vegetation in the pollen-rain. The pollen–vegetation relationship is non-linear due to the over-representation of extra-local Pinus pollen in each zone. Nonetheless, the modern pollen assemblages show a general correlation with the local broad-leaved taxa and the herbaceous elements; with the exception of Rhododendron pollen, which is under-represented. Among the non-pollen palynomorphs (NPPs), the presence of coprophilous fungal spores is compatible with the grazing activities in the area. Multivariate statistical analyses performed on the surface pollen data indicate that the dataset can efficiently distinguish the different vegetation zones across the altitudinal gradient. This work provides the modern analogues for pollen-based palaeoclimatic reconstructions for the Western-Higher Himalayan region, and would also help to decipher the inception and intensification of anthropogenic activities in the region.

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“…Among the conifers, Pinus (saccate grain, regional taxon) showed high frequency in the pollen assemblages. This can be attributed to its high pollen productivity and pollen dispersal (Andersen, 1970;Bhattacharayya, 1989;Traverse, 2007;Pidek et al, 2010;Ertl et al 2012;Kar et al, 2015Kar et al, , 2016Quamar et al, 2018a, b;Bajpai and Kar, 2018;Quamar, 2020; Polygonum plebeium, the sole representative of marshy/wetland taxa (mean < 0.05%), aquatic taxa (mean < 0.5%). algal remains (mean < 0.5%), rare.…”

Section: Discussion Inferences On the Modern Pollen Rain-vegetation Relationshipmentioning

confidence: 99%

“…The other coniferous temperate forest elements (extra-regional taxa), such as Cedrus sp., Abies sp., Picea sp., Larix sp., and Juniperus sp., have much lower values in the pollen spectra and are barely recorded. This behaviour of their pollen can be attributed to lower pollen productivity and pollen dispersal efficiency (Kar et al, 2015(Kar et al, , 2016Quamar et al, 2018a, b;Bajpai and Kar, 20018) and preservation potential (Quamar, 2020). The record of pollen of Cedrus sp., Abies sp.,and Picea sp.…”

Section: Discussion Inferences On the Modern Pollen Rain-vegetation Relationshipmentioning

confidence: 99%

The modern pollen–vegetation relationship in Jammu, India: a comparative appraisal

Quamar¹,

Tiwari²,

Thakur³

2021

Acta Palaeobotanica

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An understanding of the relationship between modern pollen and vegetation is a prerequisite for reconstruction of vegetation and climate change from fossil pollen records. We conducted palynological studies of thirty-five surface soil samples from the Jammu region of India, which revealed that Pinus, among the conifers (regional needle-leaved taxa), is over-represented in the pollen assemblage due to its high production and effective dispersal of pollen. Other coniferous and broadleaved (regional and/or extra-regional) taxa have comparatively lower values in the pollen assemblages, similar to the representation of subtropical deciduous forest elements (regional), as well as shrubby (regional and/or extra-regional) taxa. This inconsistency in the pollen assemblage could be due to long-distance transport of the former by wind and/or water from the higher reaches of the Himalayas, and also because the latter have an entomogamous pollination syndrome and are not high pollen producers. The recovered pollen assemblage presents a distorted picture of the extant vegetation; hence, caution should be exercised in interpreting fossil pollen records from the study area. Principal component analysis (PCA) shows variability in the distribution of pollen from different sites in the Jammu region, perhaps the result of transport (by wind and/ or water), altitude and/or edaphic factors of the Himalayan terrain. The study should improve our understanding of the modern pollen-vegetation relationship and aid further calibration and interpretation of fossil pollen records.

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Modern pollen assemblages from Hamtah and Chhatru glaciers, Lahaul-Spiti, India: Implications for pollen–vegetation relationship in an alpine arid region of western Himalaya

Cited by 26 publications

References 27 publications

Spatiotemporal Evolution and Driving Forces of Vegetation Cover in the Urumqi River Basin

Spatiotemporal Evolution and Driving Forces of Vegetation Cover in the Urumqi River Basin

Modern pollen–vegetation relationships along an altitudinal transect in the Western Higher Himalaya, India: Palaeoclimatic and anthropogenic implications

The modern pollen–vegetation relationship in Jammu, India: a comparative appraisal

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