Modern pollen–vegetation relationship from the Mahasamund District (Chhattisgarh), central India: implications for palaeoecological reconstruction

The study of modern pollen–vegetation relationship is crucial for the proper interpretation of fossil pollen records. In the present study, a total of 29 surface samples, collected from the edge of the forested areas of the Mahasamund District, Chhattisgarh State, central India, were palynologically analysed with the principal aims of evaluating the modern pollen assemblages and understanding the modern pollen and extant vegetation relationship. The study reveals the dominance of non-arboreal pollen (NAP) taxa over the arboreal pollen (AP) taxa, suggesting open mixed tropical deciduous forest type vegetation in and around the study area. The tree taxa, on the whole, constitute an average sum of 19.78% pollen of the total pollen sum, whereas the contribution of herbs is 43.58% pollen (average sum). The major non-arboreal taxa are Cerealia/Cereal Poaceae (average value; 5.45% pollen) and Poaceae (average value; 4.34%), whereas the cultural plant pollen taxa, such as Amaranthaceae, Caryophyllaceae, Brassicaceae, <i>Cannabis sativa</i>, <i>Alternanthera</i>, and <i>Borreria</i> contribute with an average sum of 11.69% pollen to the total pollen sum. Most of the common forest elements are not recorded because they are insect-pollinated or have low pollen preservation potential, and, hence, the modern pollen assemblages do not directly reflect the actual extant vegetation occupying the landscape of the study area. This bias would also be expected in late Quaternary pollen records of central India and, hence, can provide information of the actual vegetation when analysing fossil pollen samples.

现代花粉-植被关系研究对于正确解读化石花粉记录至关重要。本研究共计采集了印度中部恰蒂斯加尔邦马休萨姆德县林区边缘的29个地表样品，开展孢粉学分析，核心目的为解析现代花粉组合特征，厘清现代花粉与现存植被的关联。研究结果显示，非乔木花粉（non-arboreal pollen, NAP）类群的丰度高于乔木花粉（arboreal pollen, AP）类群，表明研究区及周边区域的植被类型为开阔型热带落叶混交林。总体而言，乔木类群的花粉占花粉总计数的平均比例为19.78%，草本植物的花粉贡献占比平均为43.58%。主要非乔木花粉类群为栽培禾谷类/禾本科栽培作物（平均占比5.45%）与禾本科（平均占比4.34%）；而苋科、石竹科、十字花科、大麻（*Cannabis sativa*）、莲子草属（*Alternanthera*）以及丰花草属（*Borreria*）等栽培植物花粉类群的总平均占比为11.69%。多数常见森林植被类群未被检出，这是因为其为虫媒授粉植物或花粉保存潜力较低，因此现代花粉组合无法直接反映研究区景观中实际存在的现存植被。这种偏差在印度中部晚第四纪花粉记录中同样存在，因此在分析化石花粉样品时，可借助该偏差反推实际植被状况。