Vegetation dynamics in response to climate change from the wetlands of Western Himalaya,India: Holocene Indian summer monsoon variability

Abstract

India’s agricultural output, economy and societal well-being are strappingly dependent on the stability of the southwest summer monsoon precipitation, its variability and extremes. Deviations in the Indian summer monsoon (ISM) precipitation may profoundly impact the agricultural productivity and gross domestic product (GDP) of the country. Understanding the spatiotemporal dynamics of the ISM precipitation during the Holocene is significant in many respects, particularly in terms of human development and establishment of centres of civilisations. Here, pollen records of the variability in ISM precipitation and their interpretation in terms of vegetation and climate change from two wetlands (Gharana and Nanga; Ramsar sites) of the Western Himalaya (India) is presented. The results suggest that between ~8536 and 5296 cal yr BP, mixed conifer/broad-leaved forests occurred in the Jammu region (Gharana Wetland sediment profile) under a cool and dry climate, probably indicating decreased monsoon precipitation. Subsequently, they were succeeded by mixed broad-leaved/conifer forests between ~5296 and 2776 cal yr BP under a warm and humid climate with increased monsoon precipitation, partly corresponding to the Holocene Climate Optimum (HCO). Between ~2776 and 1376 cal yr BP, with more expansion of broad-leaved forest elements in response to a warm and more humid climate the dense mixed broad-leaved/conifer forests came into existence in the region, indicating a further increase in monsoon precipitation. From ~1376 cal yr BP to present, the climate deteriorated, as manifested by the replacement of dense mixed broad-leaved/conifer forests by mixed conifer/broad-leaved forests in the region. The palaeoclimatic inferences drawn from the Nanga Wetland sediment profile of Samba District match with the Gharana Wetland sediment profile of Jammu District for the late-Holocene. This study provides insights into the vegetation dynamics, associated climate change and the ISM variability from the poorly understood wetland ecosystems of Southeast Asia during the Holocene.

Keywords

HCO India Jammu and Kashmir palaeoclimate palaeovegetation south-west monsoon

Introduction

Wetlands, known as ‘Kidney of the Earth’ (Mitsch and Gosselink, 1993), play a significant role in the hydrological cycle and are also a potential source of carbon sequestration (Panigrahy et al., 2012; Prigent et al., 2001; Sarkar, 2011), although they account only for about 4% of the Earth’s ice-free land surface. Wetlands are among the most productive ecosystems and include rivers, lakes, reservoirs and so on (Panigrahy et al., 2012). Wetlands broadly comprise areas of marsh, fen, peat land or water, whether natural or artificial, permanent or temporary, with water that is static or flowing, fresh, brackish or salt, including areas of marine water, the depth of which at low tide does not exceed 6 m (www.ramsar.org). Understanding the mechanisms underlying wetlands’ responses to past climate change could provide important insights into the projection of the future of these ecosystems. Also, understanding of the past climate change in response to the variability of the Indian summer monsoon (ISM) precipitation is important both to understand the present climatic conditions and for future climatic predictions (Cai et al., 2010).

ISM provides ~80% of the annual precipitation over India during the months of June–September (Gadgil and Gadgil, 2006). India, being an agricultural country, is largely dependent on the stability, variability and extremes of the summer monsoon precipitation for its agricultural output, economy and societal well-being (Gadgil, 2003; Gadgil and Gadgil, 2006; Webster et al., 1998). Furthermore, two-thirds of the population of India depends on farm income, and >40% of the cropped area is irrigated by rains. Simultaneously, more than one-half of the country’s farm yield comes from summer crops, which depend on ISM precipitation (Liang et al., 2015). Any variation in the ISM precipitation from the long-term mean may greatly affect the agricultural productivity and gross domestic product (GDP) of the country. Understanding the climate change influenced by the ISM precipitation and its spatiotemporal patterns poses a key research challenge (Turner and Annamalai, 2012) with significant implications on the rise and fall of ancient human civilisations (Buckley et al., 2010; Cook et al., 2010; Dixit et al., 2014, 2018; Dutt et al., 2018; Leipe and Tarasov, 2014; Staubwasser et al., 2003; Wasson et al., 2013; Zhang et al., 2008 and references therein). Keeping in view the paramount significance of ISM, which influences the agriculture-based socio-economic development of the country, this study was undertaken from the Western Himalaya, India.

Western disturbances (WDs), which are actually cyclonic storms associated with the mid-latitude subtropical westerly jet (SWJ), however, produce extreme precipitation over northern India and are further enhanced over the Himalayas because of orographic land–atmosphere interactions. During December, January and February, WDs snowfall is the dominant precipitation input to establish and sustain regional snowpack, replenishing regional water resources (Dimri et al., 2015). During winter, the Himalayan region is prone to severe weather because of large amounts of snowfall produced by WDs. Topographic heterogeneity, land-use variability and varying snow cover extent, nonetheless, are important climate controls of the ISM (Boos and Kuang, 2010).

The effects of the monsoon are preserved in various proxies such as lacustrine sediments, peat deposits, soil, tree rings, ice, cave deposits and marine sediments (Singhvi et al., 2010). Pollen grains recovered from the wetland ecosystems, which comprise lakes, reservoirs and so on, serve as an important proxy for palaeovegetation and palaeoclimate reconstructions (Chen et al., 2006; Faegri and Iversen, 1964; Gasse et al., 1991; Sun and Wu, 1987). Variations in monsoon (ISM) precipitation, its frequency and magnitude could be reflected by pollen-derived vegetation records from the wetland ecosystems (Bonnefille et al., 1999; Gaussen et al., 1965; Ghosh et al., 2015; Gunnell, 1997; Kar et al., 2002; Kar and Quamar, 2018; Prasad et al., 2014; Quamar, in preparation; Quamar et al., 2017; Rawat et al., 2015 and references therein). A considerable body of research has been carried out on palaeovegetation and palaeoclimatic reconstruction from the temperate areas of the Kashmir valley, based on megafloral remains (Puri, 1947, 1948; Vishnu-Mittre and Robert, 1973) as well as on lacustrine sedimentary pollen records (Dodia, 1988; Gupta, 1991; Gupta et al., 1984, 1988; Gupta and Sharma, 1989; Sharma et al., 1985; Sharma and Vishnu-Mittre, 1969; Singh, 1964; Vishnu-Mittre and Sharma, 1966). Bhattacharyya (1989) and Sekhar (2000), on the basis of pollen and geochemical records, conducted studies from the alpine lakes of Ladakh region and provided insights into vegetation dynamics and associated climate change. Das et al. (2006) using petrography, major, trace and rare-earth elements, revealed that the geochemical signatures of Mansar sediments can be used as a proxy to delineate the provenance, source area weathering and tectonic setting of the Siwalik basin. However, there has been little reconstruction on the palaeovegetation and contemporary palaeoclimate from Jammu region (but see Trivedi and Chauhan, 2008, 2009; Quamar, in preparation, who conducted pollen-based studies from Mansar and Surinsar Lakes as well as from Bajalta Lake, respectively, of Jammu region and provided evidence for early- to late-Holocene vegetation dynamics and contemporary climate in the region). This study has been carried out with the principal objective of providing a record of pollen-based vegetation dynamics and contemporary climate change in response to the variations in ISM precipitation during the Holocene (~10.7 k cal yr BP) from the Jammu and Samba Districts of Jammu and Kashmir (Western Himalaya), India. The reason behind the selection of present sites in the Western Himalaya for such studies is that most of the precipitation (~80–90%) takes place because of ISM in these regions. The inferences drawn here have also been correlated with the results of other relevant studies. The opportunity is also taken to examine the human impact, agricultural practices and its subsequent rates, as well as the status of water levels in wetlands during different temporal phases, which were also possibly influenced by variations in the ISM precipitation.

Regional setting

Geographical setting

Gharana Wetland (GW) is located about 45 km southwest of Jammu Township near the Indo-Pak International Border in the Ranbir Singh (RS) Pura Tehsil of Jammu District (32 º 36’ 51.52’’ N: 74º 38’ 58.15’’ E; 281 m a.s.l.), Jammu and Kashmir (J&K), India. However, Nanga Wetland (NW) is situated about 47 km southeast of Jammu Township at Samba District (32 º 33’ 15.44’’ N: 75º 06’ 55.70’’ E; 384 m a.s.l.), J&K, India (Figure 1a–c). The physiography of Jammu region is characterised by the presence of a plain area to the south of the Siwalik hills and Lesser Himalayan Mountains northwards up to the Pir Panjal range and is represented by an intricate mosaic of mountain ranges and hills characterised with river terraces, valleys and gorges (Mir, 2003). Geologically, silt deposits dominate in the Jammu foothills, both in the northeast (Ravi basin) and the northwest (Chenab basin), suggesting transportation by siltation process (Wiggs, 1997) in the channel/bank of rivers under reduced flow conditions (Chakrapani, 2005). The fluctuations in the water budget because of seasonality act as a factor in sporadic high sediment load in rivers. The fine silt deposits of Jammu suggest that high sediment influx is coupled with higher precipitation that corresponds to increase in the averaged basin-erosion rates during the late Pleistocene and Holocene (Ganjoo and Kumar, 2012). Alluvial soils having little clay content, poor in lime and nitrogenous content but rich in phosphates, potash and magnesia as well as stony and sandy soils are the chief soil types in the study area (Mir, 2003), which supports the cultivation of crops around the study area.

Figure 1.

(a) Map of India showing the site of investigation (red circles) in Jammu and Kashmir, India. (b) Map of Jammu and Kashmir showing the district boundaries and the location of wetlands under investigation. (c) Shuttle radar topographic mission (SRTM) digital elevation map (DEM) of Jammu, Jammu and Kashmir, India, showing the location of the study areas at Jammu and Samba Districts (the red circles show the sampling site at GW and NW), Western Himalaya, India.

Climate

The climate of Jammu region on account of its topography and location is diverse (Mir, 2003). The summer season starts in March and ends in June. The average summer temperature is 29.6°C with June being the hottest month. The winter season ranges from December to February. Average winter temperature is 17.7°C with January being the coldest month. The rainy season commences in July and the foothill plains and the Siwalik region of Jammu receive rains caused by the southwest monsoon (June–September; SWM/ISM). The average annual precipitation is 710 mm. The retreating monsoon starts in mid-September. According to the climate classification system proposed by Köppen (1918), Jammu region has a monsoon-influenced humid subtropical climate (Cwa). Nearest CRU TS 4.01, 0.5 × 0.5 gridded climate data points, 1901–2016, showing mean monthly precipitation and temperature around GW and NW, Jammu and Samba Districts (Harris et al., 2014) is shown in Figure 2 (Supplementary File 1, available online). The area receives some winter precipitation during the winter months (December, January and February) because of the WDs.

Figure 2.

Nearest CRU TS 4.01, 0.5 × 0.5 gridded climate data point, 1901–2016, showing mean monthly precipitation and temperature around GW and NW, Western Himalaya, India.

Vegetation

The vegetation of Jammu region is mainly characterised by the presence of sub-tropical pine forests, lower Siwalik Chirpine (Pinus roxburghii), pine forests, sub-tropical dry evergreen forests, Himalayan moist temperature forests, Himalayan dry temperature forests, and sub-alpine and moist-alpine forests. However, the vegetation of Jammu plains is of dry mixed deciduous type. The scrub-forest dominates the sub-mountain and semi-mountainous zones. In the outer hill, the flora is totally different from the middle mountains, sub-mountainous and semi-mountainous zones with Deodar (Cedrus libani) as the dominant tree species. Chirpine and Deodar, however, are the important tree species in the middle mountain zone (Mir, 2003; Sharma and Kachroo, 1981; Singh et al., 2002). Owing to the variation in altitude, topography, climate and edaphic conditions and influence of the biotic setting and human interaction with nature, diverse forest types exist in the Jammu region. The common associates of the forests in and around the study areas are shown in Table 1.

Table 1.

Common associates of the forests in the study areas.

Name of taxa	Habits	Name of families
Pinus roxburghii Sarg.	Tree	Pinaceae
Cedrus libani A.Rich.	Tree	Pinaceae
Quercus dilatataTenore	Tree	Fagaceae
Q. ilex L.	Tree	Fagaceae
Mallotus philippinensis (Lam.) Muell. Arg.	Tree	Euphorbiaceae
Acacia catechu (L. f.) P.J.H. Hurter & Mabb.	Tree	Fabaceae
A. modesta Wall.	Tree	Fabaceae
Syzygium cumini (L.) Skeels.	Tree	Myrtaceae
Flacourtia indica (Burm. f.) Merr.	Tree	Salicaceae
Butea monosperma Taub.	Tree	Fabaceae
Lannea coromandelica (Houtt.) Merr.	Tree	Anacardiaceae
Mangifera indica L.	Tree	Anacardiaceae
Ficus benghalensis L.	Tree	Moraceae
Dalbergia sissoo Roxb.	Tree	Fabaceae
Rubus fruticosus G.N. Jones	Tree	Rosaceae
Elaeodendrum roxburghii W & A.	Tree	Celasteraceae
Rhododendron arboretum Sm.	Tree	Ericaceae
Prinsepia utilis Royle	Tree	Rosaceae
Woodlandia heynei Sant & Merch	Tree	Rubiaceae
Dodonea viscosa Jacq.	Shrub	Sapindaceae
Nyctanthes arbour-tristis Linn.	Shrub	Oleaceae
Adhatoda vasica (L.) Nees	Shrub	Acanthaceae
Woodfordia fruticosa (L.) Kurtz	Shrub	Lythraceae
Zizyphus jujuba Mill.	Shrub	Rhamnaceae
Indigofera heterantha Wall.	Shrub	Fabaceae
Colebrookea oppositifolia Sm.	Shrub	Lamiaceae
Nerium sp. L.	Shrub	Apocynaceae
Daphne cannabina Wall. ex W.W.Sm. & Cave	Shrub	Thymelaeceae
Adhatoda vasica Nees	Shrub	Acanthaceae
Argyrolobium flaccidum (Royle) Jaub. & Spach	Shrub	Fabaceae
Berberis sp. L.	Shrub	Berberidaceae
Daphne sp. L.	Shrub	Thymelaeaceae
Mimosa rubicaulis Lamk	Shrub	Fabaceae
Gymnosporia royleana Wall. ex M.A. Laws	Shrub	Celastraceae
Myrsine Africana L.	Shrub	Primulaceae
Punica granatum L.	Shrub	Lythraceae
Zanthoxylum alatum Mill.	Shrub	Rutaceae
Ziziphus vulgaris Lam.	Shrub	Rhamnaceae
Pittosporum nepalense Rheder & Wils	Shrub	Pittosporaceae
Indigofera cassioides Rott. ex. DC.	Shrub	Fabaceae
Colebrookia oppositifolia Sm.	Shrub	Lamiaceae
Nerium indicum Mill.	Shrub	Apocynaceae
Reinwardtia indica Dumont.	Shrub	Linaceae
Emblica tsjarian Cottam. DC.	Shrub	Phyllanthaceae
Antidesma diandrum Roth	Shrub	Phyllanthaceae
Eranthemum pluchellum Andr.	Shrub	Acanthaceae
Caessalpinia decapetata Alston.	Shrub	Fabaceae
Acalypha Hassk.	Herb	Euphorbiaceae
Ajuga bracteosa Wall. ex. Benth	Herb	Lamiaceae
Andrpsace rotundifolia Hook. f.	Herb	Primulaceae
Apluda mutica L.	Herb	Poaceae
Arisaema wallichianum Hook.f.	Herb	Araceae
Brassica sp. L.	Herb	Brassicaceae
Artemisia L.	Herb	Asteraceae
Bupleurum falcatum L.	Herb	Apiaceae
B. setaceum Fenzl	Herb	Apiaceae
Calamintha clinopodium Mill.	Herb	Lamiaceae
Malva rotundifolia L.	Herb	Malvaceae
Pilea umbrosa Wall. ex Benth	Herb	Urticaceae
Themeda anathera Hack.	Herb	Poaceae
Cymbogon martini Wats.	Herb	Poaceae
Paspalum commersoni Lamk.	Herb	Poaceae
Thysanolaena maxima Kuntze	Herb	Poaceae
Polygonum L.	Herb	Polygonaceae
Members of Poaceae	Herb	Poaceae
Members of Brassicaceae	Herb	Brassicaceae
Members of Amaranthaceae	Herb	Amaranthaceae
Members of Boraginaceae	Herb	Boraginaceae
Members of Ranunculaceae	Herb	Ranunculaceae
Members of Rosaceae	Herb	Rosaceae
Members of Cyperaceae	Herb	Cyperaceae
Phaera vahlii Benth.	Climber	Fabaceae
Hiptage benghalensis Kurz.	Climber	Malpighiaceae
Shuteria densifolia Benth.	Climber	Fabaceae
Clematis brandis L.	Climber	Ranunculaceae
Pueraria tuberose D.C.	Climber	Fabaceae
Argyeria thomsonii Craib ex. Bahu	Climber	Convolvulaceae
Dregea volubilis Benth.	Climber	Apocynaceae

Materials and methods

Fieldwork and sediment sampling

For this study, two sedimentary pollen profiles were collected, encompassing a distance of ~80 km: one (GW) from RS Pura sector of the Jammu District (Figure 4a and b) and the other (NW) from the Samba District of Jammu and Kashmir (Western Himalaya), India (Figure 5a and b). A 1.5-m deep sediment profile was dug out with the help of spade, mattock and other related apparatus from GW. A total of 25 profile samples were collected: 20 samples at 5-cm intervals (0–100 cm depth) and 5 samples at 10-cm intervals (100–150 cm depth) from this profile for palaeoclimatic studies. In addition, six bulk samples were also collected for getting the radiocarbon (¹⁴C) date of the profile at different intervals. On the basis of the variation in sediment texture at different depths, three prominent lithozones are apparent from top to bottom in the profile. The topmost lithozone is composed of blackish clay soil with rootlets followed by blackish clayey soil. The bottommost stratum is made up of brownish clayey soil with some sand particles (Figure 4c and d). Another 1.6-m deep sedimentary profile was collected by adopting the above said approach from NW. In totality, 19 samples were collected from this profile: 6 samples at 5-cm intervals (0–30 cm depth) and 13 samples at 10-cm intervals (30–160 cm) for pollen analysis. Besides, five bulk samples were also taken at different intervals for radiocarbon (¹⁴C) dating. Three prominent lithozones are apparent from top to bottom in this profile, also on the basis of dissimilarity in sediment texture at various depths. The topmost lithozone is composed of blackish clayey soil with rootlets followed by brownish clayey soil. The bottommost stratum is made up of brownish clayey soil with sand and small pebbles (Figure 5c and d).

All the samples of both the sedimentary profiles from two different wetland areas were separately put in different polythene bags and taken to the Birbal Sahni Institute of Palaeosciences (BSIP), Lucknow, for maceration and further analysis. Proper care was, furthermore, taken to avoid mixing of samples (profile as well as radiocarbon (¹⁴C) dating samples from both the sedimentary profiles) during their collection and sample processing/maceration.

Radiocarbon (¹⁴C) dating of GW sedimentary pollen profile

Out of the six bulk samples, two samples rich in carbon content have been radiocarbon dated (7170 ± 70 yr BP at 112.5 cm depth and 800 ± 80 yr BP at 12.5 cm depth) at BSIP, Lucknow, through conventional radiocarbon dating technique, considering the organic carbon fraction. The organic rich sediment sample (>500 g; after manually removing the rootlets and unknown woods as well as further cleaning and sieving) was subjected to 10% HCl (hydrochloric acid) to remove carbonate content, if any. After repeated rinsing for pH stabilisation, the sediment sample dried at 95°C was combusted in the continuous flow of oxygen to obtain carbon dioxide. This resulting carbon dioxide was collected and converted to acetylene and then benzene using standard catalyst and procedures. The counting was carried out on a liquid scintillation counter (Quantulus 1220). IntCal 13 calibration curve (Reimer et al., 2013) was used to calibrate these conventional ¹⁴C dates in the OxCal software Version 4.3 (Bronk Ramsey, 2001; Table 2). To establish the age–depth relationship, a Poisson process deposition model (Bayesian age-depth modelling; Bronk Ramsey, 2008) was followed. The model showed all agreement indices and convergence indices higher than the critical values, thus, both the ¹⁴C samples were kept in the model. The final age–depth model is shown in Figure 6, with a 95% probability for the age of every depth.

Table 2.

Calibration of ¹⁴C dates as well as extrapolation and interpolation of the dates at different depths of the pollen zones of Gharana Wetland (GW) sediment pollen profile.

Depth (cm)	Lab code	¹⁴C age (yr BP)	Calibrated median age (cal yr BP; 95% confidence level)	Dates of different pollen zones (cal yr BP)
112.5	BS-4019	7170 ± 70	7996	Pollen Zone I: 150–120 cm = ~10,696–8536 Pollen Zone II: 120–75 cm = ~8536–5296 Pollen Zone III: 75–40 cm = ~5296–2776 Pollen Zone IV: 40–20 cm = ~2776–1336 Pollen Zone IV: 20–0 cm = ~1336–present
12.5	BS-4021	800 ± 80	747

These calibrated dates were interpolated and extrapolated to decipher the vegetation dynamics and coeval climatic changes in the region in a definite time frame. The two calibrated dates, that is, 7996 cal yr BP at 112.5 cm depth and 747 cal yr BP at 12.5 cm depth were used to calibrate the sedimentation rate, which is 72 years/cm. Assuming the sedimentation rate to be constant, four more dates were calibrated after interpolation and extrapolation of the dates at the point of zone boundaries made in the pollen diagram, that is, 10,696 cal yr BP at 150 cm depth, 8536 cal yr BP at 120 cm depth, 5296 cal yr BP at 40 cm depth and 1336 cal yr BP at 20 cm depth to describe the temporal changes in the sequential pattern of vegetation and coeval climate in the region.

Radiocarbon (¹⁴C) dating of NW sedimentary pollen profile

For NW sedimentary pollen profile, three samples, out of the five samples collected, were ¹⁴C dated (3080 ± 200 yr BP at 140 cm depth; 2520 ± 140 yr BP at 110 cm depth and 690 ± 70 yr BP at 80 cm depth) at the BSIP, Lucknow. IntCal 13 calibration curve (Reimer et al., 2013) was used to calibrate these conventional ¹⁴C dates in the OxCal software version 4.3 (Bronk Ramsey, 2001; Table 3). To establish the age–depth relationship, a Poisson process deposition model (Bayesian age-depth modelling; Bronk Ramsey, 2008) was followed. The model showed all agreement indices and convergence indices higher than the critical values, thus, all the three ¹⁴C samples were kept in the model. The final age–depth model is shown in Figure 7, with a 95% probability for the age of every depth.

Table 3.

Calibration of ¹⁴C dates as well as extrapolation and interpolation of the dates at different depths of the pollen zones of Nanga Wetland (NW) sediment pollen profile.

Depth (cm)	Lab code	¹⁴C age (yr BP)	Calibrated median age (cal yr BP; 95% confidence level)	Dates of different pollen zones (cal yr BP)
140	BS-4011	3080 ± 30	3384	Pollen Zone I: 160–120 cm = ~3984–2784 Pollen Zone II: 120–80 cm = ~2784–1584 Pollen Zone III:80–40 cm = ~1584–320 Pollen Zone IV: 40–0 cm = ~320–present
110	BS-4010	2520 ± 20	2481
80	BS-4009	690 ± 70	643

These calibrated dates were interpolated and extrapolated to decipher the vegetation dynamics and contemporary climatic changes in the region in a definite time frame. The three calibrated dates, that is, 3384 cal yr BP at 140 cm depth, 2481 cal yr BP at 110 cm depth and 643 cal yr BP at 80 cm depth were used to calibrate the sedimentation rate, which were not uniform (in this case) because of the variation in sediment composition throughout the profile. The sedimentation rate between 140 cm and 110 cm depths was calibrated to 30 years/cm, using the two cal yr BP dates, that is, 3384 cal yr BP at 140 cm depth and 2481 cal yr BP at 110 cm depth. For the upper part of the profile, the sedimentation rate has been calibrated at 8 years/cm, taking into account the cal yr BP date 643 (cal yr BP) at 80 cm depth and assuming the surface to be modern. These two sedimentation rates have facilitated to interpolate and extrapolate the dates at the point of zone boundaries made in the pollen diagram, that is, 3984 cal yr BP at 160 cm depth, 2784 cal yr BP at 120 cm depth, 1584 cal yr BP at 80 cm depth and 320 cal yr BP at 40 cm depth to describe the vegetation dynamics and contemporary climate in the region during the specified time frame.

Pollen preparation, microscopic examination and construction of pollen diagram

Laboratory preparations for the extraction of pollen and spores from sediment samples followed the Erdtman (1943) method. Chemical treatments successfully removed humus (and also deflocuulate the pollen and spores from the sediment samples), silica and cellulose using 10% KOH, 40% HF and an acetolysis mixture consisting of concentrated sulphuric acid (H₂SO₄) and acetic anhydride (C₄H₆O₃) in a 1:9 ratio, respectively. For microscopic examination, the samples were finally prepared in 50% glycerine solution to make the solution homogeneous. A few drops of phenol were also added in the solution to avoid any microbial contamination.

Pollen and spore counts were made under a transmitted light optical microscope (Olympus BX50) with attached DP 26 software for photography. The identification of pollen and spores (Pollen plate 1, see Figure 3) was assisted by authored reference material (Gupta and Sharma, 1987; Nair, 1965; Nayar, 1990; Quamar and Srivastava, 2013) and the regional reference collections held at the BSIP Herbarium, Lucknow. More than 300 terrestrial pollen grains were counted per sample. Pollen percentages were calculated using the total pollen sum (TPS) of terrestrial plant pollen only. Pollen of aquatic plants, marshy taxa as well as spores of algae, ferns and fungi were excluded from the TPS, however, their percentages were calculated using the TPS. The pollen diagrams (Figures 8 and 9 for GW sediment pollen profile; Supplementary File 2, available online and Figures 10 and 11 for NW sediment pollen profile; Supplementary File 3, available online) were constructed using TILIA and TG View software (Grimm, 1990). Taxa were grouped according to their life form and ecology (CONISS; Grimm, 1987) and arranged in the pollen diagrams as trees, shrubs, herbs, marshy taxa, aquatics, algal remains, ferns and fungal spores.

Pollen plate 1.

Pollen grains and spores recovered from the study areas.

Explanation of pollen plate 1:
1 . Pinu
2. Cedrus
3. Abies
4. Picea
5. Alnu
6. Quercus
7. Betula
8. Carpinus
9. Corylus
10. Ulmus
11. Juglans
12. Juniperus
13. Mallotus
14. Poaceae
15. Malvaceae
16. Ephedra
17. Cheno/Am (Amaranthaceae)
18. Caryophyllaceae
19. Tubuliflorae
20. Liguliflorae
21. Artemisia
22. Cerealia
23. Lemna
24. Potamogeton
25. Spirogyra
26. Zygnema
27. Monolete
28. Trilete I
29. Trilete II
30. Glomus
31. Diplodia
32. Curvularia
33. Tetraploa
34. Nigrospora
35. Helminthosporium
36. Alternaria

Figure 3.

Pollen plate 1.

Figure 4.

(a) and (b) General view of Gharana Wetland. (c) and (d) Trench profile with the lithological details as well as samples for pollen analysis and radiocarbon dating.

Figure 5.

(a) and (b) General view of Nanga Wetland. (c) and (d) Trench profile with the lithological details as well as samples for pollen analysis and radiocarbon dating.

Figure 6.

Bayesian age–depth model of the GW sediment pollen profile, Jammu District.

Figure 7.

Bayesian age–depth model of the NW sediment pollen profile, Samba District.

Figure 8.

Pollen diagram of conifers and broad-leaved tree taxa from GW, Jammu District.

Figure 9.

Pollen diagram of shrubs, terrestrial herbs, marshy, aquatics, algal remains, ferns and fungal spores from GW, Jammu District.

Figure 10.

Pollen diagram of conifers and broad-leaved tree taxa from NW, Samba District.

Figure 11.

Pollen diagram of shrubs, terrestrial herbs, marshy, aquatics, algal remains, ferns and fungal spores from NW, Samba District.

Results

Description of pollen diagrams from GW sediment pollen profile

The pollen diagram (Figures 8 and 9) has been divided into five distinct pollen zones (GW–I, GW–II, GW–III, GW–IV and GW–V), based on changes in the frequencies of prominent arboreals and non-arboreal taxa to interpret the temporal vegetation dynamics and contemporary climate in the region. These pollen zones are made on the basis of the recovered plant pollen taxa, especially arboreals from sub-tropical, temperate and alpine areas (Table 4) and are designated with the initials ‘GW’ after the name of the site of investigation, Gharana Wetland. The pollen zones numbering from bottom to top are described in the following.

Table 4.

Plant pollen (and spore) taxa from sub-tropical, temperate and alpine areas, recovered in this study.

Arboreal taxa (trees and shrubs)		Non-arboreal taxa (herbaceous taxa)	Ferns and other pteridophytic spores	Algal and fungal spores
Subtropical forest elements (regional tree taxa)	Temperate forest and alpine elements (extra-regional tree and shrubby taxa)	Terrestrial herbs: Poaceae (grasses) Cultural pollen taxa: Cerealia, Cheno/Am (Amaranthaceae), Caryophyllaceae, Artemisia sp., Alternanthera sp., Plantago sp., Brassicaceae, Urticaceae, Cannabis sativa Heathland taxa: Tubuliflorae (Asteraceae), Aconitum sp. (Ranunculaceae), Oldenlandia sp. (Rubiaceae), Malvaceae, Xanthium sp. (Asteraceae), Mimosaceae, Liguliflorae (Asteraceae), Boraginaceae, Potentilla sp. (Rosaceae) Marshy taxa: Cyperaceae (Sedges), Solanum sp., Polygonum plebeium, P. serrulatum, Pimpinella sp., Polygala sp. Aquatic taxa: Typha sp., Potamogeton sp., Lemna sp., Nymphoides sp.	Monolete fern spores, Trilete fern spores, Lycopods, Ceratopteris sp.	Algal spores: Zygospores of Zygnema sp., Spirogyra sp., Botryococcus sp., Pseudoschizaea sp. Fungal spores: Glomus sp., Diplodia sp., Curvularia sp., Nigrospora sp., Helminthosporium sp., Tertraploa sp., Cookeina sp., Alternaria sp., and so on
Conifers: Pinus sp. Broad-leaved taxa: Ulmus sp., Juglans sp., Quercus sp., Mallotus sp., Fraxinus sp., Bombax sp., Syzygium sp.	Conifers: Cedrus sp., Abies sp., Picea sp., Larix sp., Podocarpus sp., Juniperus sp. Broad-leaved taxa: Alnus sp., Betula sp., Carpinus sp., Corylus sp., Acer sp., Ilex sp., Salix sp., Aesculus sp., Celtis sp., Skimmia sp., Alpine scrub: Ephedra sp. Tropical, sub-tropical and warm temperate: Dodonea sp., Croton sp.

Pollen Zone GW–I (150–120 cm; ~10,696–8536 cal yr BP)

This pollen zone covering a time bracket of ~10,696–8536 cal yr BP is palynologically barren except for the presence of a few pollen grains of Pinus sp. and grasses (Poaceae).

Pollen Zone GW–II (120–75 cm; ~8536–5296 cal yr BP)

This pollen zone with a solitary radiocarbon date of 7170 ± 70 cal yr BP (120–75 cm depth) and encompassing a time interval of ~8536 and 5296 cal yr BP is characterised by the presence of higher frequencies of arboreals, especially conifers over the non-arboreal taxa, constituting the mixed conifer/broad-leaved forests. Among the conifers (average ~60% pollen), Pinus sp. (average ~33% pollen) is recorded in very high frequencies, followed by Cedrus sp. (average ~15% pollen). The broad-leaved taxa contribute with an average value of ~12% pollen in this pollen zone. Poaceae have high frequencies with an average of ~37% pollen, whereas Cerealia and other cultural pollen taxa contribute with an average value of 17% pollen to the TPS. Tubuliflorae and other heathland taxa have an average of ~10% pollen in the TPS. Marshy (average ~1% pollen) and aquatic taxa (average ~20%) are recorded in low to high values, respectively. Algal spores are represented in low values (<1%). Pteridophytic spores comprising trilete and monolete fern spores, lycopods and Ceratopteris sp. have an average value of ~3.5% to the total pollen and spore count. The fungal spores are also recorded in moderate values in this pollen zone (average ~9%).

Pollen Zone GW–III (75–40 cm; ~5296–2776 cal yr BP)

This pollen zone with a time interval of ~5296 and 2776 cal yr BP has shown the presence of mixed broad-leaved/conifer forests in the region. Among the broad-leaved taxa (average ~54% pollen), Alnus sp., Betula sp., Carpinus sp. and Quercus sp. are dominant (with average ~14%, 13%, 8% and 6% pollen, respectively) over the conifers (average ~45% pollen). Among the conifers, the values of Pinus sp. (average ~25% pollen) decreased comparatively as the values of Cedrus sp. (average ~14.5% pollen). Poaceae has an average of ~36% pollen and are recorded in comparatively low values compared with the preceding pollen zone, whereas Cerealia and other cultural plant pollen taxa increased a bit and contributed with an average value of ~20% pollen to the TPS. Tubuliflorae and other heathland taxa increased comparatively and contributed with an average of ~19% pollen to the TPS. Marshy taxa increased a bit and recorded with average ~3% pollen, whereas aquatic taxa are recorded with average ~4% pollen with decreased value. Algal spores are represented in low values (average ~2%) and have increased comparatively. Pteridophytic spores such as trilete and monolete fern spores as well as lycopods and Ceratopteris sp. are recorded in comparatively good values. The fungal spores decreased a bit compared with the preceding pollen zone and are recorded with an average of ~7.4%.

Pollen Zone GW–IV (40–20 cm; ~2776–1336 cal yr BP)

This pollen zone with a temporal range of ~2776–1336 cal yr BP has shown the presence of mixed broad-leaved/conifer forests in the region. A conspicuous reduction in Pinus sp. and Cedrus sp. (average ~8.3% and ~4% pollen, respectively) among the conifers (average ~16% pollen) has been recorded in this pollen zone compared with the preceding pollen zones. Simultaneously, broad-leaved taxa (average ~84% pollen) expanded comprising increase in the values of Alnus sp. and Betula sp. (average 21% pollen each), Quercus sp. (average 16%), Ulmus sp. (average 10%), Carpinus sp. (average 9%) and Corylus sp. (average ~7%) compared with the preceding two pollen zones. Poaceae has an average of ~33% pollen and decreased compared with the preceding two pollen zones. Cerealia and other cultural pollen taxa also decreased comparatively and contributed with an average value of 18% pollen to the TPS. Tubuliflorae and other heathland taxa increased comparatively and contributed with an average of ~26% pollen to the TPS. Marshy taxa decreased comparatively, whereas aquatic taxa remained somewhat the same as in the preceding pollen zone. Algal spores are represented in moderate values (average 3.5% ) and have increased values comparatively. Pteridophytic spores such as trilete and monolete fern spores are recorded in high values in this pollen zone (average ~7%). The fungal spores decreased compared with the preceding two pollen zones and are recorded in moderate values comparatively (average ~5%).

Pollen Zone GW–V (20–0 cm; ~1336 cal yr BP to present)

This topmost pollen zone with a single radiocarbon date of 800 ± 80 cal yr BP (5–20 cm depth) and covering a time bracket of ~1336 cal yr BP to present has shown the presence of mixed conifer/broad-leaved forests in the region. Pinus sp. (average ~26% pollen), Cedrus sp. (average ~15%) and Abies sp. (average ~8%) among the conifers (average ~54%) have been recorded in high frequencies compared with the preceding pollen zone. However, the broad-leaved taxa (average ~45%) have decreased comparatively, which comprise Alnus sp. (average 11%), Betula sp. (average ~8%), Quercus sp. (average 9.4%), Corylus sp. and Ulmus sp. (average ~6% each) and are encountered in comparatively low frequencies as in the preceding two pollen zones. Poaceae has an average of ~41% pollen and are recorded in very high frequencies compared with the preceding pollen zones. Cerealia and other cultural pollen taxa decreased a bit comparatively and contributed with an average value of 14.3% pollen to the TPS. Tubuliflorae and other heathland taxa also decreased comparatively and contributed with an average of ~23% pollen to the TPS. Marshy and aquatic taxa remained somewhat the same as in the preceding pollen zone. Algal spores are represented in low values (average 1.2%) and have decreased values comparatively. Pteridophytic spores which include trilete and monolete fern spores as well as lycopods are recorded in comparatively low values in this pollen zone (average ~5%). The fungal spores increased compared with the preceding two pollen zones and are recorded in high values comparatively (average ~8.5%).

NW sediment pollen profile

The pollen diagram (Figures 10 and 11) has been divided into four diverse pollen zones (NW–I, NW–II, NW–III and NW–IV) on the basis of the varying frequencies of the prominent arboreals and non-arboreal taxa to interpret the temporal vegetation dynamics and associated climate in the region. These pollen zones are also made on the basis of the recovered plant pollen taxa, especially arboreals from sub-tropical, temperate and alpine areas (Table 4) and are designated with the initials ‘NW’ after the name of the site of investigation, Nanga Wetland. The pollen zones numbering from bottom to top are described in the following.

Pollen Zone NW–I (160–120 cm; ~3984–2784 cal yr BP)

This pollen zone with a solitary radiocarbon date of 3080±200 cal yr BP (130–150 cm depth) and covering a time bracket of ~3984–2784 cal yr BP is palynologically unproductive and is characterised by the presence of a few pollen of Pinus sp. and members of the family Poaceae.

Pollen Zone NW–II (120–80 cm; ~2784–1584 cal yr BP)

This pollen zone with a single radiocarbon date of 2520 ± 140 cal yr BP (100–120 cm depth) and encompassing a time span of ~2784 and 1584 cal yr BP is characterised by the presence of mixed broad-leaved/conifer forests. Among the broad-leaved taxa (average ~52% pollen), the pollen of Alnus sp. (average ~16%), Betula sp. (average 16.5%), Ulmus sp. (average ~8%), Carpinus sp. (average ~5%), Corylus sp. (average ~3%) and Quercus sp. (average ~2%) are encountered in moderately high frequencies and dominate over the conifers (average ~20%). Pinus sp. (average ~9%) is recorded in high frequencies followed by Cedrus sp. (average ~5%) and Abies sp. (average ~3%) among the conifers. Poaceae is highly recorded with an average of ~37% pollen, whereas Cerealia and other cultural plant pollen taxa contribute with an average value of 11% pollen to the TPS. Tubuliflorae and other heathland taxa contributed with an average of 18% pollen to the TPS. Marshy (average ~2%) and aquatic taxa (average ~4% pollen) are moderately recorded. Algal spores are represented in low values (average <1%). Trilete and monolete fern spores have good values (~7%). The fungal spores are recorded in high values (average ~17%).

Pollen Zone NW–III (80–40 cm; ~1584–320 cal yr BP)

This pollen zone covering a time interval of ~1585 and 320 cal yr BP has shown the presence of mixed conifer/broad-leaved forests in the region. The values of Pinus sp. (average ~22% pollen) increased comparatively as the values of Cedrus sp. (average ~15% pollen) and Abies sp. (average ~6%) in this pollen zone. Among the broad-leaved taxa (average 48% pollen), Alnus sp. (average ~13%), Betula sp. (average 13%), Carpinus sp. (average ~8%), Ulmus sp. (average ~6%), Corylus sp. (average 4%) and Quercus sp. (average ~2%) are encountered in low frequencies compared with the preceding pollen zone. Poaceae have decreased values (average ~33% pollen) compared with the preceding pollen zone, whereas Cerealia and other cultural plant pollen taxa increased and contributed with an average value of 21% pollen to the TPS. Tubuliflorae and other heathland taxa also increased comparatively and contributed with an average of ~22% pollen to the TPS. Marshy taxa increased slightly and recorded an average of ~2% pollen, whereas aquatic taxa are recorded with an average of ~3.4% pollen with a slightly decreased value. Algal spores are represented in comparatively low values (average ~4%). Trilete and monolete fern spores have an average value of ~5%. The fungal spores decreased compared with the preceding pollen zone and are recorded in moderate values comparatively (average ~7%).

Pollen Zone NW–IV (40–0 cm; ~320 cal yr BP to present)

This topmost pollen zone with a temporal range of ~320 cal yr BP to present has shown the presence of mixed broad-leaved/conifer forests in the region. Among the broad-leaved taxa (average ~61% pollen), Alnus sp. (average 15%), Betula sp. (average ~16%), Carpinus sp. Ulmus sp. (average 9% each), Quercus sp. (average 5%) and Corylus sp. (average ~4%) are encountered in high frequencies compared with the preceding two pollen zones. Simultaneously, a conspicuous reduction in the values of conifers (average ~34%) is noticed. Pinus sp. (average ~16% pollen), Cedrus sp. (average ~9% pollen), Abies sp. (average ~4%), Picea sp. (average ~2.2% pollen) and Larix sp. (average ~1%) are recorded in moderate to low values compared with the preceding pollen zone. Poaceae has an average of ~29% pollen and decreased compared with the preceding two pollen zones. Cerealia and other cultural pollen taxa also decreased comparatively and contributed with an average value of 17% pollen to TPS. Tubuliflorae and other heathland taxa also decreased comparatively and contributed with an average of ~17% pollen to TPS. Marshy taxa (average ~2%) and aquatic taxa (average 4%) have moderate representation in the pollen diagram. Algal spores are represented in low values (average 2%) and have decreased values comparatively. Trilete and monolete fern spores are recorded moderately (average ~5%). The fungal spores increased compared with the preceding two pollen zones and are recorded in high values comparatively (average ~20%).

Discussion

Inferred palaeoclimate from GW, Jammu District with correlation of relevant studies

Palynological studies conducted on a 1.5-m deep sediment profile from GW unfolded the vegetation succession and contemporary climate in the region during the Holocene. Five phases of vegetation dynamics and associated climate change as well as human activities, agricultural practice and its subsequent state and lake-level changes have been demarcated from the Western Himalaya, India. The available very poor pollen record has revealed that between ~10,696 and 8536 cal yr BP (Pollen Zone GW–I), pluvial environment could be inferred as envisaged by the presence of sandy deposits between 100–150 cm depths in the lithocolumn. Simultaneously, no palaeovegetational inferences could be made for this phase as no significant pollen was encountered except for a few stray pollen of Pinus sp. and members of the grass family (Poaceae). This phase is partly correlatable with the inferences drawn from Surinsar Lake (~9500–7700 cal yr BP), Jammu, where similar palaeovegetation and palaeoenvironment were suggested (Trivedi and Chauhan, 2009).

Subsequently, between the time interval of ~8536 and 5296 cal yr BP (Pollen Zone GW–II), the mixed conifer/broad-leaved forests consisting of the dominance of Pinus sp., Cedrus sp., Abies sp., Picea sp. and Larix sp. and presence of comparatively less number of broad-leaved taxa such as Betula sp., Alnus sp., Ulmus sp., Quercus sp., Carpinus sp. and Corylus sp. occurred in the region under a cool and dry climate with reduced monsoon precipitation. This phase is partially correlated with the second phase of the Surinsar Lake (SL–II, ~ 7700 – 6125 cal yr BP), Jammu, wherein similar palaeovegetation and palaeoclimate were reconstructed (Trivedi and Chauhan, 2009). The herbaceous vegetation was chiefly composed of grasses (Poaceae) and Tubuliflorae, however, the record of Cerealia and other cultural plant pollen taxa such as Cheno/Am (Amaranthaceae), Caryophyllaceae, Brassicaceae, Artemisia sp., Cannabis sativa and Urticaceae indicate that agriculture was practised around the study area. Also, it is indicative of some other human activities. The presence of aquatic taxa, such as Typha, Lemna and Potamogeton, as well as freshwater algae, Botryococcus and Pseudoschizaea sp., and sedges (Cyperaceae), Polygonum plebeium, Pimpinella sp., and Polygala sp., is suggestive of the existence of a water body (lake) with marshy margin during this phase.

Between ~5296 and 2776 cal yr BP (Pollen Zone GW–III), the broad-leaved taxa such as Alnus sp., Betula sp., Carpinus sp., Corylus sp., Ulmus sp. and Quercus sp. increased compared with the preceding pollen zone. Also, Juglans sp. appeared for the first time. Simultaneously, conifers such as Pinus sp., Cedrus sp., Abies sp., Picea sp. and Larix sp. decreased. The changing vegetation assemblages with respect to the preceding pollen zone suggests that the mixed conifer/broad-leaved forests was transformed into mixed broad-leaved/conifer forests owing to the amelioration of climate, which became warm and humid under the influence of increased monsoon precipitation. This phase partly matches with the first phase of Bajalta Lake (BL–I, ~3205–2485 cal yr BP), Jammu (Quamar, in preparation); with the third phase of Surinsar Lake (SL–III, ~6125–4330 cal yr BP), Jammu (Trivedi and Chauhan, 2009), Western Himalaya; with the first phase of Deoria Tal (DT–I, ~4000 yr BP), Garhwal Himalaya (Sharma et al., 2000), India. This event of amelioration in climatic condition, in global perspective, corresponds to a certain extent with the Holocene Climate Optimum (HCO), which falls broadly within the time interval of 7000–4000 cal yr BP (Benarde, 1992). HCO has also been recorded from the bogs in the temperate belt of Kashmir (Dodia et al., 1985), the alpine belt of Marhi in Himachal Pradesh (~8000–3500 yr BP; Bhattacharyya, 1988), Dhakuri peat bog (~6000–4500 cal yr BP; Phadtare, 2000), Tso Kar lake in Ladakh (~6.9–4.8 ka BP; Demske et al., 2009) and Chandra peat bog, Lahaul, Northwestern Himalaya (~6732–3337 cal yr BP; Rawat et al., 2015). From Central India also, this HCO was recorded from Hoshangabad District, Madhya Pradesh (Chauhan and Quamar, 2012; Quamar and Chauhan, 2012), Anuppur District, Madhya Pradesh (Chauhan, 2015) and Koriya District, Chhattisgarh (Quamar and Bera, 2017). In this study, however, the effects of HCO have been found between a time frame of ~ 5297 and 2776 cal yr BP. Grasses and Tubuliflorae constitute the herbaceous vegetation in this zone. The pace of agricultural practice and other anthropogenic activities increased as Cerealia and other cultural plant pollen taxa showed an increasing trend. The water level in the wetland also increased slightly as algal spores and marshy taxa increased comparatively, though aquatics show a declining trend. Pteridophytic spores such as monolete and trilete fern spores as well as lycopods and Ceratopteris thrived well in the moist and shady places in the region.

Between ~2776 and 1336 cal yr BP (Pollen Zone GW–IV), with the comparative much expansion of the existing broad-leaved elements and a simultaneous extreme reduction in the number and frequencies of coniferous taxa suggest a further increase in monsoon precipitation. The dense mixed broad-leaved/conifer forests came into existence in the region under a warm and more humid climate during this phase. This phase partially matches with the third phase of Bajalta Lake (BL, ~1585–865 cal yr BP), Jammu, Western Himalaya (Quamar, in preparation); with the first phase of a lacustrine sediment profile from Darjeeling (Jore-Pokhari; JP–I, ~2500–1600 yr BP), Eastern Himalaya (Chauhan and Sharma, 1996), India. Human activity and the pace of cereal-based agricultural activity, though, slightly decreased comparatively in this pollen zone as Cerealia and other cultural pollen taxa showed a declining trend, however, the water level in the wetland remained almost static in this phase too as aquatic taxa maintained the status quo, algal spores increased and marshy taxa decreased comparatively.

Since ~1336 cal yr BP to present (Pollen Zone GW–V), the deterioration of climate took place as is manifested by a shift in the vegetation pattern in the region. The mixed conifer/broad-leaved forests came into being and replaced the dense mixed broad-leaved/conifer forests with the improvement and dominance of conifers such as Pinus sp., Cedrus sp., Abies sp., Picea sp. and Larix sp. and a simultaneous reduction in the broad-leaved taxa such as Alnus sp., Betula sp., Ulmus sp., Carpinus sp., Corylus sp. and Quercus sp. under a cool and dry climate possibly indicating the reduced monsoon precipitation. The findings of this phase partly coincide with the inferences drawn from the Surinsar Lake (SL–VII, ~ 800 cal yr BP to present), Jammu District (Trivedi and Chauhan, 2009), Jammu and Kashmir; with the second phase of the Naini Tal (SRT.C–II, ~ 1200–124 cal yr BP), Nainital District (Gupta, 2002), Kumaun Himalaya; with the fifth phase of the Dewar Tal area (DT–V, ~ 400 yr BP), Lesser Garhwal Himalaya (Chauhan and Sharma, 2000); with the third phase of Chharaka Tal (Sat Tal, ~1200 yr BP to present), Garhwal Himalaya (Chauhan et al., 1997); and with the second phase of a lacustrine sediment profile from Darjeeling (Jore-Pokhari; JP–II, ~1600–1000 yr BP), eastern Himalaya (Chauhan and Sharma, 1996), India. The pace of agricultural practice and other human activities showed a declining trend as Cerealia and other cultural pollen taxa decreased. The water level in the wetland also decreased and the wetland assumed a smaller dimension as is indicated by the decreased values of aquatic taxa and algal remains.

Inferred palaeoclimate from NW, Samba District with correlation of relevant studies

Pollen analysis of a 1.6-m deep sediment profile from NW has provided a late-Holocene vegetation dynamics and associated climate change in the region. Four distinct phases of vegetation dynamics and coeval climate as well as human activities, agricultural practice and its subsequent pace and lake-level changes have been inferred from the NW of Samba District, Western Himalaya, India. The available insufficient pollen assemblage has suggested that between ~3984 and 2784 cal yr BP (Pollen Zone NW–I), no definite inferences with regard to palaeovegetation could be made as no significant pollen was encountered except for a few stray pollen of Pinus sp. and members of the grass family (Poaceae). Pluvial environment could be inferred as sandy deposits between 120 and 160 cm depths in the lithocolumn are present, which might have been deposited in the said environment.

Subsequently, between ~2784 and 1584 cal yr BP (Pollen Zone NW–II), the mixed broad-leaved/conifer forests comprising the dominance of broad-leaved taxa such as Alnus sp., Betula sp., Ulmus sp., Carpinus sp., Corylus sp., Mallotus sp. and Quercus sp., and comparatively lesser conifers such as Pinus sp., Cedrus sp., Abies sp., Picea sp., Larix sp. and Juniperus sp. appeared in the region under a warm and humid climate with increased monsoon precipitation. This phase is partially correlated with the fourth phase of the Mansar Lake (ML–IV, ~ 3000–750 cal yr BP), Jammu, wherein similar palaeovegetation and palaeoclimate were reconstructed (Trivedi and Chauhan, 2008). The herbaceous vegetation was chiefly composed of grasses (Poaceae), Tubuliflorae, Aconitum sp. and Oldenlandia sp. The record of Cerealia and other cultural plant pollen taxa indicate the incipient agricultural practice and other human activities around the area of investigation. The presence of aquatic taxa, such as Typha, Lemna and Potamogeton, as well as sedges (Cyperaceae), Polygonum plebeium, Pimpinella sp. and Polygala sp., is suggestive of the existence of a water body (lake) with marshy margin during this phase. Pteridophytic fern spores, especially trilete and monolete fern spores, in moderate to high frequencies are indicative of moist and damp conditions around the study area.

Between ~1584 and 320 cal yr BP (Pollen Zone NW–III), the climate turned cool and dry as is marked by the steady improvement in coniferous taxa such as Pinus sp., Cedrus sp., Abies sp., Picea sp. and Larix sp. and a comparative substantial decrease in broad-leaved taxa such as Alnus sp., Betula sp., Ulmus sp., Carpinus sp., Corylus sp. and Quercus sp. The change in the vegetation assemblage suggests the replacement of mixed broad-leaved/conifer forests by mixed conifer/broad-leaved forests under a cool and dry climate attributable to decreased monsoon precipitation. This phase partly matches with the third phase of Bajalta Lake (BL–III, ~1585–865 cal yr BP), Jammu (Quamar, in preparation); with the seventh phase of Surinsar Lake (SL–VII, ~800 cal yr BP), Jammu (Trivedi and Chauhan, 2009), Western Himalaya, India. Grasses, Tubuliflorae, Aconitum sp. and Oldenlandia sp. also constitute the herbaceous vegetation in this zone. The pace of agricultural practice and other anthropogenic activities contrarily increased as Cerealia and other cultural plant pollen taxa showed an increasing trend. The water level in the wetland, however, decreased comparatively as aquatic taxa and algal spores showed a declining trend.

Since ~320 cal yr BP to present (Pollen Zone NW–IV), the mixed conifer/broad-leaved forests were succeeded by the mixed broad-leaved/conifer forests as can be seen with the comparative much enhancement in the number and frequencies of the existing broad-leaved elements such as Alnus sp., Betula sp., Ulmus sp., Carpinus sp., Corylus sp., Mallotus sp. and Quercus sp. A concurrent and comparative tremendous reduction in the coniferous taxa such as Pinus sp., Cedrus sp., Abies sp., Picea sp. and Larix sp. suggests an increase in monsoon precipitation. The mixed broad-leaved/conifer forests again came into existence in the region under a warm and humid climate. This phase partially matches with the fourth phase of Bajalta Lake (BL–IV, ~865 cal yr BP to present), Jammu, Western Himalaya (Quamar, in preparation), with the third phase of the Naini Tal (SRT.C–III, ~ 124 cal yr BP), Nainital District (Gupta, 2002), Kumaun Himalaya, India. Human activity and the pace of cereal-based agriculture activity, though, slightly decreased comparatively in this pollen zone as Cerealia and other cultural pollen taxa has shown a declining trend, however, the water level in the wetland increased in this phase as aquatic taxa, algal spores increased and marshy taxa showed an increasing trend comparatively. Pteridophytic spores such as monolete and trilete fern spores flourished in moist and shady places during this phase.

This study provides pollen records of the variability in ISM precipitation during the Holocene from the Western Himalaya, India. Ghosh et al. (1978) were of the opinion that the monsoons are caused by movement of the Inter tropical Convergence Zone (ITCZ) over the equatorial region. More specifically, the summer rains associated with the South-west monsoon (SWM) are initiated by the seasonal northward movement of the ITCZ because of warming of the Asian continents during summer (Wright et al., 2008). A significant change in vegetation succession pattern was observed with the changing monsoonal (SWM/ISM) behaviour during the Holocene from the Western Himalaya, India. Palynological investigations with low chronology and sampling resolutions, nevertheless, have created hindrance in generating high-resolution ISM reconstructions. So, multi-proxy studies are, further, required with more radiocarbon (¹⁴C) and/or AMS ¹⁴C dates and pollen samples from the Western Himalaya to gather more detailed information on the late Quaternary vegetational and climatic variations. Furthermore, the study provides insights into the variability of ISM precipitation during the Holocene, which could be helpful in future climatic predictions and also for a scientifically sound policy planning for the welfare of society.

A note on the abundance of extra-local (high-altitude) pollen

The encounter of taxa from high-altitude temperate and alpine regions (Table 4) such as Cedrus sp., Abies sp., Picea sp., Podocarpus sp., Juniperus sp. and Larix sp. (coniferous tree taxa) as well as Alnus sp., Betula sp., Carpinus sp., Corylus sp., Juglans sp., Ulmus sp., Salix sp., Fraxinus sp., Ilex sp., Celtis sp. and Acer sp., (broad-leaved tree taxa) as well as Ephedra sp., Skimmia sp., Croton sp. and Dodonea sp. (shrubby taxa) from the study areas indicate long-distance transport of their pollen. These elements might also be growing possibly at lower altitudes than at present, which facilitated their good representation of the above said taxa around the sampling sites and probably the treeline shifted towards higher elevation because of change in climate.

Correlation of the inferred palaeoclimate with the two studied wetlands

The correlation of the pollen diagrams constructed from GW and NW, Western Himalaya (India), allows to suggest that the palaeoclimatic inferences of the two sites match for the late-Holocene (~2.8 ka; Figure 12). The warm and more humid climate ~2776–1336 cal yr BP of GW matches with the temporal phase of ~2784–1584 cal yr BP of NW pollen diagram, wherein almost similar palaeovegetation and palaeoclimate was inferred. Similarly, the cool and dry climate ~1336 cal yr BP to present of GW is correlatable with the time slash of ~1584–320 cal yr BP of NW pollen diagram. The correlation of the vegetation succession patterns and their contemporary climate of the two wetlands of Western Himalaya, India, during the Holocene are subject to the influence of altitude, topography, microclimate and so on, as well as human impacts.

Figure 12.

Correlation diagram of inferred palaeoclimates from Gharana and Nanga wetlands, Western Himalaya, India, showing the two wetland areas with similar climatic conditions during the late-Holocene.

Conservation of wetlands: A detailed account

Wetlands harbour a large number of threatened birds, in addition to a variety of wildlife which are vital for their conservation (Kumar et al., 2005). Wetlands are essential for maintaining biodiversity, water harvesting and water availability. Also, wetlands play an important and pivotal role in increasing the economy of the local populace as well as the concerned State exchequer.

Gharana Wetland (Literal meaning: Welcome Home (Ghar aana in Hindi)) is a semi-arid wetland of approximately 1 km² surface area adjacent to agricultural areas on the Indo-Pakistan border near Gharana village in RS Pura Tehsil of Jammu District. It is irregular in shape and is the abode and/or paradise of migratory birds (Jamwal et al., 2017; Pandotra and Sahi, 2014; Sharma and Minakshi, 2012). The notified area of Gharana, barring a small patch of marshy pond and adjoining area, comprises agricultural fields. It is a naturally maintained, rain-fed swamp with bottom-surface of loamy clay with decaying vegetation, especially macrophytes such as Eichhornia spp., and Hydrilla spp. and Typha spp. (the common reed). The additional sources of water are spillover from the Ranbir canal and surface runoff from the agricultural areas. It serves as feeding, roosting and wintering grounds for large numbers of migratory water birds during their palaeartic to oriental migration (Pandotra and Sahi, 2014). GW Conservation Reserve (GWCR) provides a unique habitat not only for birds (nine globally threatened species), but also for many meso-predators and small carnivores, herbivores, primates and reptiles. The primary threats to this wetland are human encroachment and its corollaries such as cattle grazing, bathing, stray dogs and military shelling across the Indo-Pakistan border (Jamwal et al., 2017). Variations in habitat condition may cause changes in the relative abundance of bird species composition (Caziani and Derlindati, 2000; Gracía and Yorio, 2007). It is declared as an Important Bird Area (IBA) by Birdlife International (Butchart et al., 2012) and comes under the Jammu and Kashmir (J&K) Wildlife Protection Act (1978). To identify focal areas for implementation of conservation, IBA arises from a global network (Heath et al., 2000). On the other hand, NW, spreading over an area of 1.28 km² near Ramgarh area of Samba District, has vanished without a trace. This wetland reserve (Nanga Wetland Conservation Reserve; NWCR), though, existed about 25–30 years ago in the form of a vast pond which has now been completely dried out. Flocks of migratory birds used to arrive in winters, but with the passage of time inhabitants started using the land for cultivation and birds started ignoring this wetland because of the increased human activity.

Nature as well as man-made activities influences the wetlands, which demands frequent monitoring. Developmental activities and population pressure cause damage to the wetlands and the very existence of these natural resources is being witnessed currently. So, in view of the accelerating pressure, regular updation regarding the status of the wetlands is all the more significant. Moreover, concerted efforts are required on a war footing to conserve and preserve these natural resources as wetlands are the first among the victims of modern development and degrading with the passage of time, irrespective of their obvious positive contributions (Panigrahy et al., 2012; Sarkar, 2011). The impact of climate change on the wetlands may be seen in the form of drying up as well as disappearance of small wetlands and transformation of permanent wetlands into seasonal ones, subject to greater variation in the water levels, resulting in the loss of carbon sinks. Dramatic fluctuations in the water levels, furthermore, will possibly enhance the release of greenhouse gases (GHGs) from these systems and biodiversity within affected wetlands will decrease. The combination of wetlands disappearing and water levels fluctuating greatly in the wetlands will lead to a feedback cycle that will perpetuate the loss of wetlands by reducing carbon sinks, increasing GHG fluxes to the atmosphere and further enhancing the greenhouse effect (Sarkar, 2011). National Wetland Inventory and Assessment (NWIA) Information Brochure, a satellite-based wetland atlas of India, released by the Ministry of Environment and Forests (MoEF), Government of India on 9 June 2011, will form the basis of a comprehensive wetland conservation strategy.

Meanwhile, public awareness programmes regarding the hazards caused by the destruction of wetlands as well as on their conservational benefits should be initiated not only by the concerned government organisation (s), but also by non-government organisations (NGOs) at different levels, including villages, districts and the likes to conserve the wetlands in view of their tremendous role being played in the hydrological cycle and carbon sequestration. Bombay Natural History Society (BNHS), Wildlife Preservation Society of India-WLPSI (Dehradun), World Wild Life Fund (WWF), India (now renamed as World Wide Fund for Nature – WWFN) and the Central Board of Wild Life – CBWL (now renamed as Indian Board of Wild Life – IBWL) should take cognisance of the vanishing and/or vanished wetlands for their conservation, wise use as well as resurrection, keeping in view the benefits for the biodiversity, wildlife and society as well. The conservation of wetlands should be incorporated in the curricula of various schools, colleges and universities to spread awareness among the students as well. It is also high time to strictly implement the existing J&K Wildlife Protection Act (1978) to conserve the wetlands.

Conclusion

The following conclusions can be presented:

Four phases of variations in the ISM precipitation were mainly observed: (1) decreased monsoon precipitation during ~8536–5296 cal yr BP, (2) increased monsoon precipitation during ~5296–2776 cal yr BP, (3) further increase in monsoon precipitation during ~2776–1336 cal yr BP and (4) decrease in monsoon precipitation during ~1336 cal yr BP to present.

Pluvial environment, however, was suggested between ~10,696 and 8536 cal yr BP around GW, Jammu District and between ~3984 and 2784 cal yr BP around NW, Samba District on the basis of acute scarcity of pollen grains and simultaneous prevalence of sandy deposits in the respective litho-columns of the two sedimentary pollen profiles.

This study suggests the time slice for the period of the HCO as ~5296–2776 cal yr BP.

The palaeoclimatic inferences drawn from the NW sedimentary pollen profile of Samba District matches with the latter phases of the GW sedimentary pollen profile.

Agricultural practice, its subsequent pace and human activity as well as the changes in water level of the wetlands are in agreement with the variations in SW monsoonal precipitation.

Local and regional correlations of this study reveal that the vegetation succession patterns during the Holocene are certainly comparable, but each site has its own characteristics because of the influence of altitude, topography, microclimate and so on, as well as human impacts.

Supplemental Material

Supplementary_file_1_GW_and_NW_Preciptn_Temp_Xl_sheet_Grapg – Supplemental material for Vegetation dynamics in response to climate change from the wetlands of Western Himalaya, India: Holocene Indian summer monsoon variability

Supplemental material, Supplementary_file_1_GW_and_NW_Preciptn_Temp_Xl_sheet_Grapg for Vegetation dynamics in response to climate change from the wetlands of Western Himalaya, India: Holocene Indian summer monsoon variability by M Firoze Quamar in The Holocene

Supplemental Material

Supplementary_file_2_GW – Supplemental material for Vegetation dynamics in response to climate change from the wetlands of Western Himalaya, India: Holocene Indian summer monsoon variability

Supplemental material, Supplementary_file_2_GW for Vegetation dynamics in response to climate change from the wetlands of Western Himalaya, India: Holocene Indian summer monsoon variability by M Firoze Quamar in The Holocene

Supplemental Material

Supplementary_file_3_NW – Supplemental material for Vegetation dynamics in response to climate change from the wetlands of Western Himalaya, India: Holocene Indian summer monsoon variability

Supplemental material, Supplementary_file_3_NW for Vegetation dynamics in response to climate change from the wetlands of Western Himalaya, India: Holocene Indian summer monsoon variability by M Firoze Quamar in The Holocene

Footnotes

Acknowledgements

I am grateful to Professor (Dr) Sunil Bajpai, Director, Birbal Sahni Institute of Palaeosciences (BSIP), Lucknow (Uttar Pradesh), India, for providing the infrastructure facilities to complete this research work and also for permission to publish. The Department of Science & Technology (DST), Ministry of Science & Technology, Government of India, New Delhi, India, is thankfully acknowledged for financial assistance in the form of DST Fast Track Young Scientist Project (SR/FTP/ES-81/2013, dated 20 January 2014) to conduct the study and Mr Deepak Khanna, Principal Chief Conservator of Forest (PCCF) Wildlife (WL), Jammu and Kashmir, India, for his kind permission to conduct the fieldwork. Dr Samina Amin Charu, Research Officer at the office of PCCF (WL) is acknowledged for discussion and also for very kindly cooperating with me during the entire process of taking permission for conducting the fieldwork. Thanks are also due to Dr (Mrs) Anjum Farooqui, Scientist–F, BSIP for critically going through the manuscript and also for her kind suggestions; to Dr Biswajeet Thakur, Scientist-D, BSIP for very kindly creating ; to Dr Ruby Ghosh, Scientist-C, BSIP and Dr Mayank Shekhar, Young Scientist of DST, tenable at BSIP for their kind help. I am also thankful to the reviewers for their insightful comments on an earlier version of the manuscript. Professor Frank Chambers, Associate Editor, The Holocene is thanked for encouragement and cooperation.

Funding

The research work was carried out with the financial assistance received from the Department of Science & Technology (DST), Ministry of Science & Technology, Government of India, New Delhi, India under the DST Fast Track Young Scientist Project (SR/FTP/ES-81/2013, dated 20 January 2014).

References

Benarde

(1992) Global Warming. New York: John Wiley and Sons.

Bhattacharyya

(1988) Vegetation and climate during postglacial period in the vicinity of Rohtang Pass, Great Himalayan Range. Pollen Spores 30(3–4): 417–427.

Bhattacharyya

(1989) Vegetation and climate during the last 30,000 years in Ladakh. Palaeogeography, Palaeoclimatology, Palaeoecology 73: 25–38.

Bonnefille

Anupama

Barboni

et al . (1999) Modern pollen spectra from tropical South India and Sri Lanka: Altitudinal distribution. Journal of Biogeography 26: 1255–1280.

Boos

Kuang

(2010) Dominant control of the South Asian Monsoon by orographic insulation versus plateau heating. Nature 463: 218–222.

Bronk

Ramsey C

(2001) Development of radiocarbon calibration program. Radiocarbon 43 (2A): 355–363.

Bronk

Ramsey C

(2008) Deposition models for chronological records. Quaternary Science Reviews 27: 42–60.

Buckley

Anchukaitis

Penny

et al . (2010) Climate as a contributing factor in the demise of Angkor, Cambodia. Proceedings of the National Academy of Sciences 107: 6748–6752.

Butchart

Scharlemann

Evans

et al . (2012) Protecting important sites for biodiversity contributes to meeting global conservation targets. PLoS ONE 7(3): e32529.

10.

Cai

Tan

Cheng

et al . (2010) The variation of summer monsoon precipitation in central China since the last deglaciation. Earth and Planetary Science Letters 291: 21–31.

11.

Caziani

Derlindati

(2000) Abundance and habitat of high Andean flamingos in Northwestern Argentina. Waterbirds 23(Special Publication 1): 121–133.

12.

Chakrapani

(2005) Factors controlling variations in river sediment loads. Current Science 88(4): 569–575.

13.

Chauhan

(2015) Vegetation and climatic variability in southeastern Madhya Pradesh, India since mid-Holocene, based on pollen records. Current Science 109(5): 956–965.

14.

Chauhan

Quamar

(2012) Mid-Holocene vegetation vis-à-vis climate change in southwestern Madhya Pradesh, India. Current Science 103(12): 1455–1461.

15.

Chauhan

Sharma

(1996) Late Holocene vegetation of Darjeeling (Jore-Pokhari), eastern Himalaya. Palaeobotanist 45: 125–129.

16.

Chauhan

Sharma

(2000) Late Holocene vegetation and climate in Dewar Tal area, Inner Lesser Garhwal Himalaya. Palaeobotanist 49(3): 509–514.

17.

Chauhan

Sharma

Rajagopalan

(1997) Vegetation and climate during Late Holocene in Garhwal Himalaya. Palaeobotanist 46(1): 211–216.

18.

Chen

Huang

Zhang

et al . (2006) Humid little ice age in arid central Asia documented by Bosten Lake, Xinjiang, China. Science in China Series D: Earth Sciences 49(12): 1280–1290.

19.

Cook

Anchukaitis

Buckley

et al . (2010) Asian monsoon failure and mega drought during the last millennium. Science 328: 486–489.

20.

Das

Al-Mikhlafi

Kaur

(2006) Geochemistry of Mansar Lake sediments, Jammu, India: Implication for source-area weathering, provenance, and tectonic setting. Journal of Asian Earth Sciences 26(6): 649–668.

21.

Demske

Tarasov

Wünnemann

et al . (2009) Late glacial and Holocene vegetation, Indian monsoon and westerly circulation dynamics in the Trans-Himalaya recorded in the pollen profile from high-altitude Tso Kar Lake, Ladakh, NW India. Palaeogeography, Palaeoclimatology, Palaeoecology 279(3): 172–185.

22.

Dimri

Niyogi

Barros

et al . (2015) Western disturbances: A review. Review of Geophysics 53: 225–246.

23.

Dixit

Hodell

Giesche

et al . (2018) Intensified summer monsoon and urbanization of Indus Civilization in northwest India. Scientific Reports 8: 4225.

24.

Dixit

Hodell

Sinha

et al . (2014) Abrupt weakening of the Indian summer monsoon at 8.2 kyr BP. Earth and Planetary Science Letters 391: 16–23.

25.

Dodia

(1988) Climate of Kashmir during the last 700,000 years: The Baltal pollen profile. Proceedings of the National Academy of Sciences 54(3): 481–489.

26.

Dodia

Agrawal

Vora

(1985) New pollen data from the kashmir bogs: A summary. In: Current Trends in Geology: Climate and Geology of Kashmir, 6. New Delhi: Today and Tomorrow’s Printers and Publishers, pp. 101–108.

27.

Dutt

Gupta

Wünnemann

et al . (2018) A long arid interlude in the Indian summer monsoon during ~4350 to3450 cal yr BP contemporaneous to displacement of the Indus valley civilization. Quaternary International 482: 83–92.

28.

Erdtman

(1943) An Introduction to Pollen Analysis. Waltham, MA: Chronica Botanica Co.

29.

Faegri

Iversen

(1964) Text Book of Pollen Analysis. Waltham, MA: Chronica Botanica Co.

30.

Gadgil

(2003) The Indian monsoon and its variability. American Review of Earth and Planetary Sciences 31: 429–467.

31.

Gadgil

(2006) The Indian monsoon, GDP and agriculture. Economic and Political Weekly 41(47): 4887–4895.

32.

Ganjoo

Kumar

(2012) Late Quaternary fine silt deposits of Jammu, NW Himalaya: Genesis and climatic significance. Journal of Earth System Sciences 121(1): 165–182.

33.

Gasse

Arnold

Frontes

et al . (1991) A 13,000-year climate record from western Tibet. Nature 353: 742–745.

34.

Ghosh

Bera

Sarkar

et al . (2015) A ~50 ka record of monsoonal variability in the Darjeeling foothill region, eastern Himalayas. Quaternary Science Reviews 114: 100–115.

35.

Ghosh

Pant

Dewan

(1978) Influence of the Arabian Sea on the Indian summer monsoon. Tellus 30: 117–125.

36.

Gracía

Yorio

(2007) Breeding habitat requirements and selection by Orlog’s Gull (Larus atlanticus), a threatened species. Auk 124: 1201–1212.

37.

Grimm

(1987) CONISS: A FORTRAN 77 program for stratigraphically constrained cluster analysis by the method of incremental sum of squares. Computers and Geosciences 13: 13–35.

38.

Grimm

(1990) TILIA and TILIA.GRAPH, PC spreadsheet and graphics software for pollen data, INQUA. Working Group on Data-handling Methods Newsletter 4: 5–7.

39.

Gunnell

(1997) Relief and climate in South Asia: The influence of the Western Ghats on the current climate pattern of Peninsular India. International Journal of Climatology 17: 1169–1182.

40.

Gupta

(2002) Palaeovegetation and past climate of Late Holocene from temperate zone of Naini Tal District, Kumaun Himalaya. Acta Palaeontologica Sinica 41(4): 517–523.

41.

Gupta

(1991) Changing pattern of vegetation in the intermontane basin of Kashmir since 4 Ma: A palynological approach. Palaeobotanist 40: 354–373.

42.

Gupta

Sharma

(1987) Pollen Flora of North-West Himalaya. Lucknow: Indian Association of Palynostratigraphers.

43.

Gupta

Sharma

(1989) Vegetational history and palaeoenvironment of Hirpur Loc. I, Lower Karewa. Palaeobotanist 37(2): 155–158.

44.

Gupta

Sharma

Dodia

et al . (1984) A palynological interpretation of climate changes in Kashmir (India) during the past three million years. In: Whyte

(ed.) Proceedings of Palaeoenvironment of East Asia from Mid-Tertiary II. Hong Kong: Centre of Asian Studies, University of Hong Kong, pp. 553–568.

45.

Gupta

Sharma

Dodia

et al . (1988) Palynostratigraphy and palaeoenvironment of Kashmir, Hirpur Loc. III. In: Current Trends in Geology, Vol. VI (Climate and Geology of Kashmir). New Delhi: Today & Tomorrow’s Printers and Publishers, pp. 75–90.

46.

Harris

Jones

Osborn

et al . (2014) Updated high-resolution grids of monthly climatic observations – the CRU TS3.10. International Journal of Climatology 34: 623–642.

47.

Heath

Evans

Haccom

et al . (2000) Important Bird Areas in Europe Priority Sites for Conservation. Vol. 1: Northern Europe. Vol. 2: Southern Europe. Cambridge: Birdlife International.

48.

Jamwal

Chandan

Rattan

et al . (2017) Survey of avifauna of the Gharana wetland reserve: Implications for conservation in a semi-arid agricultural setting on the Indo-Pakistan border. BMC Zoology 2: 7.

49.

Kar

Quamar

(2018) Pollen-based Quaternary palaeoclimatic studies in India: An overview of recent advances. Palynology. Epub ahead of print 14 March. DOI: 10.1080/01916122.2017.1410502.

50.

Kar

Ranhotra

Bhattacharyya

et al . (2002) Vegetation vis-à-vis climate and glacial fluctuations of the Gangotri glacier since last 2000 years. Current Science 82: 347–351.

51.

Köppen

(1918) Klassifikation der Klimate nach Temperatur, Niederschlag und Jahreslauf. Petermanns Geographische Mitteilungen 64: 193–203, 243–248.

52.

Kumar

Sati

Tak

et al . (2005) Handbook on Indian Wetland Birds and Their Conservation. Kolkata: Zoological Survey of India.

53.

Leipe

Tarasov

(2014) A Holocene pollen record from the northwestern Himalayan lake Tso Moriri: Implications for palaeoclimatic and archaeological research. Quaternary International 348: 93–112.

54.

Liang

Brook

Kotlia

et al . (2015) Panigarh cave stalagmite evidence of climate change in the Indian Central Himalaya since AD 1256: Monsoon breaks and winter southern jet depressions. Quaternary Science Reviews 124: 145–161.

55.

Mir

(2003) Geography of Jammu: A Regional Analysis. New Delhi: Dilpreet Publishing House.

56.

Mitsch

Gosselink

(1993) Wetland. 2nd Edition. New York: Van Nostrand Reinhold Press.

57.

Nair

PKK

(1965) Pollen Grains of Western Himalayan Plants. Mumbai: Asia Publishing House.

58.

Nayar

(1990) Pollen Flora of Maharashtra State, India. New Delhi: Today & Tomorrow Printers & Publishers.

59.

Pandotra

Sahi

(2014) Feeding guilds of avifauna of Gharana Wetland Reserve-Jammu (J&K), India. International Research Journal of Environmental Sciences 3(4): 27–33.

60.

Panigrahy

Murthy

TVR

Patel

et al . (2012) Wetlands of India: Inventory and assessment at 1: 50,000 scale using geospatial techniques. Current Science 102(6): 852–856.

61.

Phadtare

(2000) Sharp decrease in summer monsoon strength 4000–3500 cal yr BP in the Central Higher Himalaya of India based on pollen evidence from alpine peat. Quaternary Research 53: 122–129.

62.

Prigent

Matthews

Aires

et al . (2001) Remote sensing of global wetland dynamics with multiple satellite datasets. Geophysical Research Letters 28: 4631–4634.

63.

Puri

(1947) The occurrence of tropical fig (Ficus cunia Buch-Ham.) in the Karewa beds at Liddarmarg, Pir Panjal Range, Kashmir with remarks on the sub-tropical forests of the Kashmir Valley during the Pleistocene. Journal Indian Botanical Society 26(3): 131–135.

64.

Puri

(1948) The flora of the Karewa series of Kashmir and its phytogeographical affinities with chapter on the method used in identification. Indian Forester 74(3): 105–122.

65.

Quamar

(2018) Late Holocene vegetation vis-á-vis climate change influenced by the ISM variability from the Western Himalaya Himalaya, India. Grana.

66.

Quamar

Bera

(2017) Pollen records related to vegetation and climate change from northern Chhattisgarh, central India during the Late Quaternary. Palynology 41(1): 17–23.

67.

Quamar

Chauhan

(2012) Late Quaternary vegetation, climate as well as lake-level changes and human occupation from Nitaya area in Hoshangabad District, southwestern Madhya Pradesh (India), based on pollen evidence. Quaternary International 263: 104–113.

68.

Quamar

Nawaz Ali

Nautiyal

et al . (2017) Vegetation and climate reconstruction based on a ~4 ka pollen record from north Chhattisgarh, central India. Palynology 41(4): 504–515.

69.

Quamar

Srivastava

(2013) Modern pollen rain in relation to vegetation in Jammu, Jammu and Kashmir, India. Journal of Palynology 49: 19–30.

70.

Rawat

Gupta

Sangode

et al . (2015) Late Pleistocene– Holocene vegetation and Indian summer monsoon record from the Lahaul, Northwest Himalaya, India. Quaternary Science Reviews 114: 167–181.

71.

Reimer

Bard

Bayliss

et al . (2013) IntCal 13 and MARINE13 radiocarbon age calibration curves 0-50,000 years cal BP. Radiocarbon 55(4): 1869–1887.

72.

Sarkar

(2011) Ramsar Convention of India. Current Science 101(10): 1266–1268.

73.

Sekhar

(2000) Interpretation of past climatic changes around Tsokar Lake, Ladakh for the last 33 ka on the basis of chemical data. Palaeobotanist 49: 519–527.

74.

Sharma

Vishnu-Mittre (1969) Studies of Postglacial vegetational history from the Kashmir Valley-2. Babarishi and Yusmaidan. Palaeobotanist 17: 231–243.

75.

Sharma

Kachroo

(1981) Flora of Jammu & Plants of Neighbourhood. Dehra Dun: Bishen Singh Mahendra Pal Singh.

76.

Sharma

Chauhan

Rajagopalan

(2000) Vegetation and climate in Garhwal Himalaya during last 4,000 years. Palaeobotanist 49: 501–507.

77.

Sharma

Gupta

Dodia

et al . (1985) Palynostratigraphy and palaeoenvironment, Dubjan, Lower Karewa, Kashmir. In: Current Trends in Geology, Vol. VI (Climate and Geology of Kashmir). New Delhi: Today & Tomorrows Printers and Publishers, pp. 69–73.

78.

Sharma

Minakshi

(2012) Impact of anthropogenic pressure on habitat utilization by the waterbirds in Gharana Wetland (reserve), Jammu (J&K, India). International Journal of Environmental Science 2(4): 2050–2062.

79.

Singh

(1964) A preliminary survey of the Postglacial vegetational history of the Kashmir Valley. Palaeobotanist 12(1): 73–108.

80.

Singh

Uniyal

(2002) Flora of Jammu and Kashmir. Vol. 1. Pteridophytes, Gymnosperms and Angiosperms (Ranunculaceae-Moringaceae). Kolkata: Botanical Survey of India.

81.

Singhvi

Bhattacharyya

Kale

et al . (2010) Instrumental, terrestrial and marine records of the climate of south Asia during the Holocene: Present status, unresolved problems and societal aspects. In: Mitra

Sharma

(eds) Global Environmental Changes in South Asia. Dordrecht: Springer, pp. 54–124.

82.

Staubwasser

Sirocko

Grootes

et al . (2003) Climate change at the 4.2 ka BP termination of the Indus Valley civilization and Holocene Asian monsoon variability. Geophysical Research Letters 30: 1425.

83.

Sun

(1987) Distribution and quantity of sporopollen and algae in surface sediments of the Dianchi Lake, Yunnan province. Marine Geology & Quaternary Geology 7(4): 81–92 (in Chinese with English abstract).

84.

Trivedi

Chauhan

(2008) Pollen proxy records of Holocene vegetation and climate change from Mansar Lake, Jammu region, India. Current Science 95(9): 1347–1354.

85.

Trivedi

Chauhan

(2009) Holocene Vegetation and Climate Fluctuations in Northwest Himalaya, Based on Pollen Evidence from Surinsar Lake, Jammu Region, India. Journal of Geological Society of India 74: 402–412.

86.

Turner

Annamalai

(2012) Climate change and the South Asian summer monsoon. Nature Climate Change 2(8): 587–595.

87.

Vishnu-Mittre Robert

(1973) Pollen analysis and palaeobotany of impressions bearing sediments in the Lower Karewa. Palaeobotanist 20(3): 344–355.

88.

Vishnu-Mittre Sharma

(1966) Studies of Post glacial vegetational history from the Kashmir Valley-1, Haigam Lake. Palaeobotanist 15(12): 185–212.

89.

Wasson

Sundriyal

Chaudhary

et al . (2013) A 1000-year history of large floods in the Upper Ganga catchment, central Himalaya, India. Quaternary Science Reviews 77: 156–166.

90.

Webster

Magaña

Palmer

et al . (1998) Monsoons: Processes, predictability, and the prospects for prediction. Journal of Geophysical Research 103: 14451–14510.

91.

Wiggs

GFS

(1997) Sediment mobilization by the wind. In: Thomas

David

(eds) Arid Zone Geomorphology. New York: John Wiley and Sons, pp. 351–371.

92.

Wright

Bryson

Schuldenrein

(2008) Water supply and history: Harappa and the Beas regional survey. Antiquity 82: 37–48.

93.

Zhang

Cheng

Edwards

et al . (2008) A test of climate, sun, and culture relationships from an 1810-year Chinese cave record. Science 322: 940–942.

Supplementary Material

Please find the following supplemental material available below.

For Open Access articles published under a Creative Commons License, all supplemental material carries the same license as the article it is associated with.

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Vegetation dynamics in response to climate change from the wetlands of Western Himalaya,India: Holocene Indian summer monsoon variability

Abstract

Keywords

Introduction

Regional setting

Geographical setting

Climate

Vegetation

Materials and methods

Fieldwork and sediment sampling

Radiocarbon (14C) dating of GW sedimentary pollen profile

Radiocarbon (14C) dating of NW sedimentary pollen profile

Pollen preparation, microscopic examination and construction of pollen diagram

Results

Description of pollen diagrams from GW sediment pollen profile

Pollen Zone GW–I (150–120 cm; ~10,696–8536 cal yr BP)

Pollen Zone GW–II (120–75 cm; ~8536–5296 cal yr BP)

Pollen Zone GW–III (75–40 cm; ~5296–2776 cal yr BP)

Pollen Zone GW–IV (40–20 cm; ~2776–1336 cal yr BP)

Pollen Zone GW–V (20–0 cm; ~1336 cal yr BP to present)

NW sediment pollen profile

Pollen Zone NW–I (160–120 cm; ~3984–2784 cal yr BP)

Pollen Zone NW–II (120–80 cm; ~2784–1584 cal yr BP)

Pollen Zone NW–III (80–40 cm; ~1584–320 cal yr BP)

Pollen Zone NW–IV (40–0 cm; ~320 cal yr BP to present)

Discussion

Inferred palaeoclimate from GW, Jammu District with correlation of relevant studies

Inferred palaeoclimate from NW, Samba District with correlation of relevant studies

A note on the abundance of extra-local (high-altitude) pollen

Correlation of the inferred palaeoclimate with the two studied wetlands

Conservation of wetlands: A detailed account

Conclusion

Supplemental Material

Supplementary_file_1_GW_and_NW_Preciptn_Temp_Xl_sheet_Grapg – Supplemental material for Vegetation dynamics in response to climate change from the wetlands of Western Himalaya, India: Holocene Indian summer monsoon variability

Supplemental Material

Supplementary_file_2_GW – Supplemental material for Vegetation dynamics in response to climate change from the wetlands of Western Himalaya, India: Holocene Indian summer monsoon variability

Supplemental Material

Supplementary_file_3_NW – Supplemental material for Vegetation dynamics in response to climate change from the wetlands of Western Himalaya, India: Holocene Indian summer monsoon variability

Footnotes

Acknowledgements

Funding

References

Supplementary Material

Radiocarbon (¹⁴C) dating of GW sedimentary pollen profile

Radiocarbon (¹⁴C) dating of NW sedimentary pollen profile