A high-altitude calibration set of modern biotic proxies from the Western Himalaya, India: Pollen–vegetation relation, anthropogenic and palaeoclimatic implications

Kar, Ratan; Mishra, Kriti; Quamar, Md. Firoze; Mohanty, Ruchika Bajpai; Agrawal, Shailesh; Tripathi, Swati; Mishra, Amit Kumar

doi:10.1016/j.catena.2021.106011

Cited by 13 publications

(3 citation statements)

References 93 publications

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“…It has been observed that even if Pinus PLOS ONE is not growing in the immediate vicinity of the sampling locations, its pollen can be predominant to such an extent that it completely overwhelms the other pollen taxa in the palynological records. A bountiful abundance of Pinus pollen has been observed in the surface sediments, from other glacial sites in the Western Himalaya, as well [26,27]. Other conifers (Abies, Picea and Cedrus) constitute about 8.5% and the broad-leaved arboreals account for 6.5% of the pollen assemblage.…”

Section: Comparison Between the Surface And Sub-surface Palynological...mentioning

confidence: 94%

Early onset of aridity in the past millennium: Insights from vegetation dynamics and climate change in the alpine, cold-desert region of Trans Himalaya, India

Mohanty,

Mishra,

Mishra

et al. 2024

PLoS ONE

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Palynological analysis of surface soil and sub-surface sediments from the outwash plain of Hamtah Glacier, Lahaul-Spiti, India, has brought out the vegetation and climatic changes in the area during the last 1580 years. The arboreal and non-arboreal pollen ratio (AP/NAP) has been used to demarcate the different vegetation and climatic zones, complemented by the frequencies of the broad-leaved taxa. Lower values of thermophilous, broad-leaved arboreal taxa, indicate that the region experienced cold-arid conditions between 1580 and 1330 yr BP (AD 370–620); which can be related to the Dark Ages Cold Period (DACP). Thereafter, between 1330 and 950 yr BP (AD 620–1000), a rejuvenation of the broad-leaved elements reflects the initiation of a comparatively warm and moist phase, marking the Medieval Climatic Anomaly (MCA) in the region. The warm-moist phase was, however, short-lived, and from 950 yr BP to the Present (AD 1000 onwards), the region saw a return to cold-arid conditions, as evidenced by a sharp fall in the AP/NAP ratio. This cold-arid phase was, nevertheless, punctuated by a warm-moist period during 790 to 680 yr BP (AD 1160–1270), which marks the terminal phase of the MCA. After the termination of the MCA, the Little Ice Age (LIA) is well-marked in the area. The culmination of the long cold-arid regime is characterized by warmer conditions over the last 160 years, which is the manifestation of the Current Warm Period (CWP). Magnetic susceptibility (χlf) and sediment geochemistry (Weathering Index of Parker) were also attempted to have a multi-proxy approach, and show a general compatibility with the palynological data. The palaeoclimatic evidences suggest shorter warm periods and extended colder phases during the last 1580 years; in this high-altitude, cold-desert, Trans Himalayan region.

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Section: Comparison Between the Surface And Sub-surface Palynological...mentioning

confidence: 94%

Early onset of aridity in the past millennium: Insights from vegetation dynamics and climate change in the alpine, cold-desert region of Trans Himalaya, India

Mohanty,

Mishra,

Mishra

et al. 2024

PLoS ONE

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“…Pollen and spore counts were performed using an Olympus microscope fitted with a camera. Authored reference material (Ali et al, 2020;Kar et al, 2022;Mishra et al, 2022;Nair (1965, Nayar (1990, Quamar, 2019Quamar and Srivastava, 2013;Quamar and Stivrins, 2021) and regional reference collections kept at the BSIP Herbarium, Lucknow aided in the identification of pollen and spores (Figure S3a-d; Figure 6a, b). The Total Pollen Count (TPC) was calculated by counting 100-350 pollen-spores in each sample, depending on the enrichment of pollen-spores in the samples.…”

Section: Pollen Preparation Microscopic Examination and Construction ...mentioning

confidence: 99%

Vegetation diversity in response to monsoonal variability in the Eastern Himalaya, India over the past ~13 000 yrs

Dubey,

Ali,

Quamar

et al. 2024

The Holocene

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Monsoon precipitation plays a crucial role in shaping the diversity of vegetation in the Himalayas, both in terms of temporal and spatial distribution. While palynology has traditionally been employed to reconstruct the past climate of the Himalaya, there has been limited understanding of how monsoon-related changes affect the structure and distribution of vegetation. To address this, we analysed pollen data from a 3 m deep sedimentary profile in the higher Sikkim Himalaya to reconstruct monsoon driven changes in vegetation diversity. Our results show a highly fluctuating trend of pollen and diversity parameters at late-Pleistocene-Holocene transition for which fluctuating hydroclimatic conditions and differential pollen preservation in coarser sediments is attributed. During the Early Holocene (10,438–7934 cal yrs BP) favourable hydroclimatic conditions led to a rapid expansion of mixed broad-leaved forests, marked by higher values of richness and alpha diversity. Between 7934 and 5481 cal yrs BP, the region experienced moderate hydroclimatic conditions that facilitated expansion and diversification of woody taxa, and correlated with the global Holocene Climate Optimum (HCO). Conversely, from 5481 to3949 cal yrs BP, declining total pollen count (TPC), species richness, and alpha diversity indicates significant shifts in vegetation composition under deteriorating climatic conditions, which corresponds with the 4.2 ka event worldwide. From 3949 to 2049 cal yrs BP, an increasing yet variable trend in TPC and diversity indices, suggests warm-humid conditions prevailed in the region. During the last 1086 cal yrs, an increasing trend is recorded in the palyno assemblage and diversity parameters suggesting ameliorating climate, matches well with the Mediaeval Climate Anomaly (MCA). Our inferences suggest that the palyno assemblage and diversity parameters are quiet sensitive to warm and humid conditions.

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“…Vegetation is an integral and basic composition of the ecosystem of an area, which is sensitive to and governed by climatic changes. The distribution pattern of vegetation is strongly dependent on the climatic conditions (precipitation, temperature), soil characteristic and altitude, as well as on human impact (Chen et al, 2006; Faegri & Iversen, 1964; Gasse et al, 1991; Ivanov et al, 2007; Kar et al, 2022; Kar & Quamar, 2019; Mishra et al, 2022; Quamar & Kar, 2020b; Sun & Wu, 1987 and references cited therein). Moreover, characterising pollen, which is produced by the vegetation itself, and its spatial distribution in a geological past regarding the existing vegetation structure of an area is crucial for understanding past climatic changes (Birks & Birks, 1980, 2005; Gaillard et al, 1992; Gosling et al, 2005; Jackson & Williams, 2004; Kar & Quamar, 2019; Mohanty et al, 2024; Quamar, 2020; Quamar & Kar, 2020a; Quamar et al, 2023, 2024; Traverse, 1988 and references cited therein).…”

Section: Introductionmentioning

confidence: 99%

Multiproxy studies on the spatially distinct surface samples to reconstruct palaeoecology and palaeoclimate from the Core Monsoon Zone of India

Quamar,

Thakur,

Sharma

et al. 2024

Journal of the Palaeontological Society of India

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Palaeoclimatic reconstructions necessitate an understanding of the various biotic and abiotic responses to develop a modern analogue. The interpretation and calibration of the modern data allow us to check the lead-lag effect in different proxy parameters, which could be applied for robust palaeoclimatic reconstructions. We, in the present study, analysed pollen and diatom (biotic proxies), as well as grain size, magnetic susceptibility and geochemistry (abiotic components) of the modern soil samples, collected from the states of Madhya Pradesh and Chhattisgarh, the Core of the Monsoon Zone (CMZ) in central India. The weathered materials of the Palaeocene Cretaceous extrusive rocks and sedimentary rocks of the Late Triassic to the Upper Carboniferous are underlying the soil cover in these areas, respectively. The study revealed that the overall pollen and diatom preservation is comparatively good in the areas where the Palaeocene Cretaceous extrusive rocks are found except for the areas of human settlements, whereas the preservation of pollen and diatom was comparatively poor in areas where sedimentary rocks of the Late Triassic to Upper Carboniferous are found. The most plausible reason for this difference is the availability of nutrients which are supplied more abundantly by the easily weatherable Deccan basalt rocks compared to their sedimentary counterparts. The present study will serve as baseline information about biotic-abiotic interactions operating in the central Indian Core Monsoon Zone (CMZ). Since the intensity and duration of the rainfall in the CMZ are largely governed by the annual Indian summer monsoon rainfall (AISMR), therefore, the present study could help trace the weak or intense monsoon periods (break and active spells, respectively) of the past hundreds to thousands of years by studying the sediment profiles/cores.

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A high-altitude calibration set of modern biotic proxies from the Western Himalaya, India: Pollen–vegetation relation, anthropogenic and palaeoclimatic implications

Cited by 13 publications

References 93 publications

Early onset of aridity in the past millennium: Insights from vegetation dynamics and climate change in the alpine, cold-desert region of Trans Himalaya, India

Early onset of aridity in the past millennium: Insights from vegetation dynamics and climate change in the alpine, cold-desert region of Trans Himalaya, India

Vegetation diversity in response to monsoonal variability in the Eastern Himalaya, India over the past ~13 000 yrs

Multiproxy studies on the spatially distinct surface samples to reconstruct palaeoecology and palaeoclimate from the Core Monsoon Zone of India

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