The origin of Shola Forest in the Nilgiris, South India

Vishnu-Mittre,; Gupta, H.P.

doi:10.54991/jop.1970.860

Cited by 7 publications

(6 citation statements)

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“…A more proximate explanation for the presence of phylogenetic overdispersion in the study area is the facilitation of frost and cold intolerant evergreen woody shola species by frost and cold tolerant species with temperate or sub-tropical affinities [32,52]. Such facilitative interactions are known to generate phylogenetic overdispersion in arid and semi-arid ecosystems [24,68].…”

Section: Discussionmentioning

confidence: 99%

“…Further studies on plant functional traits linked to cold and frost tolerance, and their relationship with phylogenetic history are required to confirm this hypothesis, both within tropical and subtropical lineages, as well as between the tropical and extra-tropical lineages that constitute these upper montane communities. A more proximate explanation for the presence of phylogenetic overdispersion in the study area is the facilitation of frost and cold intolerant evergreen woody shola species by frost and cold tolerant species with temperate or sub-tropical affinities [32,52]. Such facilitative interactions are known to generate phylogenetic overdispersion in arid and semi-arid ecosystems [24,68].…”

Section: (A) Phylogenetic Overdispersion With Elevation: Niche Conver...mentioning

confidence: 92%

“…See [31] for a detailed description of the vegetation. Studies of soil carbon isotopes and fossil pollen show that sholas have expanded into grasslands during warmer, wetter periods and contracted during cooler, drier ones [32][33][34]. The western side of the plateau receives the highest rainfall (2500-5000 mm), mainly during the southwest monsoon, the southern and eastern portions of the plateau receive 1500-2000 mm annually from both the southwest and northeast monsoon and the central Nilgiris receive 900-1200 mm on average [34].…”

Section: Methods (A) Study Areamentioning

confidence: 99%

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The thermal niche and phylogenetic assembly of evergreen tree metacommunities in a mid-to-upper tropical montane zone

Das

Ratnam

2022

Proc. R. Soc. B.

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Frost and freezing temperatures have posed an obstacle to tropical woody evergreen plants over evolutionary time scales. Thus, along tropical elevation gradients, frost may influence woody plant community structure by filtering out lowland tropical clades and allowing extra-tropical lineages to establish at higher elevations. Here we assess the extent to which frost and freezing temperatures influence the taxonomic and phylogenetic structure of naturally patchy evergreen forests (locally known as shola ) along a mid-upper montane elevation gradient in the Western Ghats, India. Specifically, we examine the role of large-scale macroclimate and factors affecting local microclimates, including shola patch size and distance from shola edge, in driving shola metacommunity structure. We find that the shola metacommunity shows phylogenetic overdispersion with elevation, with greater representation of extra-tropical lineages above 2000 m, and marked turnover in taxonomic composition of shola woody communities near the frost-affected forest edge above 2000 m, from those below 2000 m. Both minimum winter temperature and patch size were equally important in determining metacommunity structure, with plots inside very large sholas dominated by older tropical lineages, with many endemics. Phylogenetic overdispersion in the upper montane shola metacommunity thus resulted from tropical lineages persisting in the interiors of large closed frost-free sholas, where their regeneration niche has been preserved over time.

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Section: Discussionmentioning

confidence: 99%

Section: (A) Phylogenetic Overdispersion With Elevation: Niche Conver...mentioning

confidence: 92%

Section: Methods (A) Study Areamentioning

confidence: 99%

See 1 more Smart Citation

The thermal niche and phylogenetic assembly of evergreen tree metacommunities in a mid-to-upper tropical montane zone

Das

Ratnam

2022

Proc. R. Soc. B.

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“…Although, several marine and continental records from eastern Arabian Sea and NW India respectively reveal a dry climatic spell during the mid-late Holocene (Caratini et al, 1991(Caratini et al, , 1994Sukumar et al, 1993;Sarkar et al, 2000), however, it could not be precisely decoded as there is spatial and temporal variability due to wider geographical locations and physiographical set ups of the different basins investigated so far (Kale & Singhvi, 2003). The pollen records from the sediment deposits from the tropical regions in India comprising south Indian mountains (Vishnu-Mittre & Gupta, 1968, 1971Vasanthy, 1988;Gupta & Bera, 1996), Rajasthan Desert (Singh et al, 1974), coastal region (Van Campo et al, 1982;Van Campo, 1986;Tissot, 1986Tissot, , 1990Farooqui & Sekar, 2002;Farooqui & Achyuthan, 2006) and Central Ganga Plain (Chauhan et al, 2009(Chauhan et al, , 2015Trivedi et al, 2013) have provided comprehensive insight into the terrestrial and coastal vegetation succession in relation to monsoon fluctuations.…”

Section: Introductionmentioning

confidence: 99%

Pollen evidence of vegetation succession, climatic changes and human impact in southern Madhya Pradesh during last ca 6,700 years

Chauhan

Bhandari²,

Sharma³

2021

JPS

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Pollen records of a 2.0 m deep sediment profile from Barehata Tal portray the vegetation scenarios and contemporaneous climatic events of southern Madhya Pradesh prior to Mid–Holocene. Between 6,700 and 6,015 cal yr BP, the region supported open mixed tropical deciduous forests comprising sparingly distributed trees, viz. Moringa oleifera, Acacia, Trewia nudiflora, Madhuca indica, Terminalia and Aegle marmelos under a warm and less–humid climate than today. The record of Cerealia pollen from the beginning of the pollen sequence denotes the cereal–based arable crop economy in the region. The lake did exist, but it was of small expanse as depicted by the deficient aquatic element, Potamogeton. Around 6,015 to 4,848 cal yr BP, the enhancement in Acacia, Moringa oleifera, Trewia nudiflora, Madhuca indica coupled with moderate increase in Terminalia, Aegle marmelos, Holoptelea, etc. suggest the proliferation of mixed deciduous forests with the arrival of a warm very humid climate attributed to active SW monsoon. The agrarian activities also intensified with the initiation of favourable climatic condition as testified by the increase in Cerealia and cropland weeds. The lake turned bigger in stretch as documented by the improvement in Potamogeton and Typha along with sporadic appearance of Zygnema. The abrupt decline in the number as well as frequencies of the trees existing earlier implies that the forest became sparse around 4,848 to 3,671 cal yr BP with the onset of a warm and dry climate, most likely due to weak SW monsoon. Between 3,671 and 2,450 cal yr BP, the expansion forests took place with the substantial rise of Acacia, Madhuca indica and Holoptelea and re–incursion of Tectona grandis, Buchanania lanzan, Schleichera oleosa, Schrebera, Aegle marmelos, Grewia, etc. This diversification of the forests signifies the advent of a warm and moderately–humid climate. There was augmentation in the agricultural practice and other human activities as evidenced from the consistent encounter of Cerealia and culture pollen. The lake attained a wider spread as a result of increased monsoon precipitation. Around 2,450 to 1,230 cal yr BP, the forests declined, which is manifested by the depletion in the prominent ingredients, excepting Grewia, Schleichera oleosa, Tectona grandis and Aegle marmelos. This change in the vegetation scenario reflects the prevalence of a warm and less–humid climate again. However, from 1,230 cal yr BP onwards, the enrichment of forests elucidates that a warm and humid climate prevailed in response to increased monsoon precipitation.

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“…I N south India though extensive works have been carried out by many workers (Menon, 1968;Vishnu-Mittre & Gupta, 1970;Gupta, 1973;Caratini et al, 1973Caratini et al, , 1991Gupta & Prasad, 1985;Vasanthy, 1988;Bera & Gupta, 1992;Bera et al, 1996Bera et al, , 1997Bera, 1999;Bonnefille et al, 1999;Bera & Farooqui, 2000;Anupama et al, 2000;Barboni & Bonnefille, 2001;Barboni et al, 2003;Farooqui et al, 2010), but no work has been recorded on modern pollen rain in Chamrajnagar District of Karnataka. However, earlier a palynological study on honey sample has been carried out from the Gundal Dam and Biligirirangaswamy area from the Chamrajnagar District (Chauhan & Murthy, 2010).…”

Section: Introductionmentioning

confidence: 99%

Modern pollen spectra from Chamrajnagar District of Karnataka, India

Basumatary¹,

Murthy²,

Bera³

2014

JPS

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A study on modern pollen rain from the Chamrajnagar District of Karnataka has been documented. The pollen study revealed the dominance of nonarboreals over arboreals. Among the arboreals, Syzygium, Eucalyptus, Meliaceae and Rutaceae are commonly represented taxa in the area. However, among nonarboreals grasses are predominant along with other typical associates namely, Tubuliflorae, Liguliflorae, Mimosa and Euphorbiaceae. The abundance of marshy taxa, viz. Cyperaceae, Polygonaceae and Onagraceae are indicative of the water logged condition in and around the area. The steady presence of cereals along with other cultural pollen, like Chenopodiaceae and Lamiaceae is strongly suggestive of the arable activity in the area. The occurrence of degraded pollen–spore along with adequate fungal elements especially Meliola, Microthyriaceae and Glomus is suggestive of aerobic microbial digenesis of rich organic debris during sedimentation. The studied palynodata will be helpful for the precise palaeoecological study in and around the study area.

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The origin of Shola Forest in the Nilgiris, South India

Cited by 7 publications

References 1 publication

The thermal niche and phylogenetic assembly of evergreen tree metacommunities in a mid-to-upper tropical montane zone

The thermal niche and phylogenetic assembly of evergreen tree metacommunities in a mid-to-upper tropical montane zone

Pollen evidence of vegetation succession, climatic changes and human impact in southern Madhya Pradesh during last ca 6,700 years

Modern pollen spectra from Chamrajnagar District of Karnataka, India

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