Modern Pollen Record on Bat Guano Deposit from Siju Cave and its Implication to Palaeoecological Study in South Garo Hills of Meghalaya, India

Abstract

Meghalaya is well known for its rich tropical biodiversity and numerous natural caves. The Siju Cave of Meghalaya, also known as cave of the bat, is among the longest caves on the Indian subcontinent. The palynological study of fifty bat-guano samples from Siju Cave and of thirty surface soil and moss cushion from the area immediate surrounding the cave reflects the close similarity between the modern pollen and vegetation in the region in the two areas sampled. The resulting palynodata comprise mainly the native flora, dominated by riparian taxa like Duabanga, Syzygium, Careya, and Ficus, along with evergreen and deciduous elements in the region. The evergreen taxa Mesua, Elaeocarpus, and Garcinia, along with Impatiens, reflect the high precipitation in the region. The climate of the region and the vegetation are strongly influenced by the Simsang River, and the heavy rainfall results in the dominance of riparian taxa and other high-rainfall indicator taxa. The occurrence of pollen from Nepenthes khasiana, an endemic and endangered plant of Meghalaya, in bat guano is significant and may be due to its insectivorous and entomophilous nature. However, medicinal plants like Swertia chirata, Cinchona, and Rauvolfia are not encountered in the bat-guano sediments, despite their luxuriant growth around the cave, and these species could be avoided by the insects due to their alkaloid contain and bitter taste. The presence of highland taxa such as Pinus, Abies, Picea, and Larix in the bat guano deposit is significant and suggestive of high winds from higher altitudes, or the pollen may be introduced by the return of migratory Siberian birds during winter to the nearby Siju wildlife and bird sanctuary. The recovery of cerealia along with Areca catechu and Citrus pollen indicate the human activity in the region. The abundance of fungal remains, namely Meliola, Glomus, and Microthyriaceae along with degraded palynomorphs are suggestive of strong microbial activity under warm and humid conditions during sedimentation in the region. The main objective of this study is to identify the potential of bat guano for palaeoecological research and as supportive data for surface and sedimentary soil profiles in the South Garo Hills of Meghalaya. The palynodata from the bat guano of the Siju Cave provides a useful source for palaeoecological information for the South Garo Hills, where intensive natural and human-caused forest fires, heavy rainfall, and soil erosion occur every year and there is a relative scarcity of the lake, wetland, and swamp habitats that normally preserve pollen.

A comprehensive procedure for pollen extraction from bat guano deposits in organic and detrital matrices

“…A growing number of studies on bat guano deposits is leading to successful environmental reconstructions [5 , 6] , as well as unique information about archeological sites [3] and shifts in bat diets [45] . Paleoecological data from guano deposits have been reported by previous studies in North America [9 , 10] and Asia [32 , 35] . They provide valuable records of climate changes in the geological past [5] , and bat ecology [4] , among other environmental parameters throughout the last several millennium [6 , 35] .…”

“…1 Locations of caves around the world where guano deposits have been studied. Red circle: our study site in Carajás, Brazil; Yellow circles: 1- Grand Canyon, Arizona, USA [5 , 6] ; 2- Eagle Creek Cave, Arizona, USA [7 , 8] ; 3- Tumbling Creek Cave, Missouri, USA [4] ; 4- Round Spring Cavern, Missouri, USA [9] ; 5- Mammoth Cave, Kentucky, USA [10] ; 6- Spring Cave, Alabama, USA [11] ; 7- Fern Cave, Alabama, USA [3] ; 8- Jackson Bay Cave Complex, Jamaica [12 , 13] ; 9- Schwallenburgh Cave, Jamaica [14] ; 10- Home Away from Home Cave, Jamaica [14] , [15] , [16] ; 11- Blanchard Cave, Eastern Caribbean [17] ; 12,13- Southeastern Spain [18 , 19] ; 14- Grotte XVI, France [20] ; 15- Măgurici Cave, Romania [21] , [22] , [23] ; 16- Ziditǎ Cave, Romania [24 , 25] ; 17- Gaura cu Muscǎ Cave, Romania [26 , 27] ; 18- Gura Ponicovei Cave, Romania [28] ; 19- Topolnița Cave, Romania [29] ; 20- Arnhem Cave, Namibia [30] ; 21- China [31] ; 22- Siju cave, India [32] ; 23- Eraaning Cave, India [33] ; 24- Batu Cave, Malaysia [34] ; 25- Niah Cave, Borneo [34] ; 26- Gangub Cave, Philippines [33] ; 27- Makangit Cave, Philippines [34 , 35] ; 28- Tabon Cave, Philippines [36] ; 29- Gomantong Cave, Indonesia [37] ; 30- Bau Cave, Indonesia [36] ; 31- New Zealand [38] ; 32- New Zealand [39] . …”

Untitled

“…Mean population size of P. giganteus in various roosting locations of the study area during 2013-2015 was calculated as 1 44.77±1.72 (mean ± SE, n=44), 122.79±1.79 (mean ± SE, n=44), and 114.38±1.85 (mean ± SE, n=44) ( Table 1). Maximum individuals (482) of Pteropus giganteus were observed in Dulalgram in the year 2013 while the minimum was in Hawaithang and Charmail (24). In the year 2014, the maximum number of the individual was recorded in Raninagar (560) and the minimum was recorded in Algapur (12).…”

“…Lakshadweep archipelago, 21 Manipur, 22 Masinagudi village, eastern part of Mudumalai Tiger Reserve, 23 Meghalaya, 24 Mizoram, 25 Mysore city, 26 Nagaland, 27 Rajasthan, 28 Sikkim, 29 Sundergarh district of Odisha, 30 Tamilnadu, 31 Tripura. 32 Northeast India harbours 65 bats species out of which 28 bat species have been reported from Assam.…”

Assessment of Plants Biodiversity in Innerline Reserve Forest, Hailakandi, Assam, India

“…It is not unexpected that up to 80% of the world's human population relies on plants (or plant products) for their primary healthcare, according to estimates from the World Health Organization (WHO) (Bodeker et al, 2003). The diversity of living beings and the ecological systems in which they coexist make up biodiversity [7][8][9][10][11][12]. A measure of diversity can be considered to represent the number of unique things and their relative frequency.…”