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

Abstract

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.

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

“…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.…”

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

“…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).…”