Vascular plant diversity of Sonaimuri Upazila, Noakhali, Bangladesh

A survey of vascular plant diversity in Sonaimuri Upazila, Noakhali, Bangladesh , was conducted from August 2019 to October 2022. This study recorded 360 species under 248 genera in 87 families, including those cultivated and planted. Based on habit distribution, there are 47% herbs, 15% shrubs, 28% trees, 9% climbers, and 1% epiphytes. The families Fabaceae, Asteraceae, Poaceae, and Euphorbiaceae were the most numerous in terms of species. Ficus and Solanum , with six species each, are the largest of the ten dominant genera found in the Sonaimuri, followed by Polygonum (5 species). For each species, a scientific name, vernacular name, family, plant group, and habit character have been presented. Many anthropogenic activities, the most prevalent of which are land grabs, agricultural expansion following vegetation clearance, infrastructure development, settlement, the gathering of fuel wood and leaf litter, significant visits, and other anthropogenic activities, are endangering the biodiversity of the study area.


INTRODUCTION
To enhance and manage biological resources responsibly, as well as to address and alleviate environmental issues, a nation must have an essential awareness of its biodiversity.Taxonomic research employing diverse data sets the foundation for comprehending and evaluating multiple facets of plant biodiversity.To confirm plant species' identities, descriptions, distributions, origins, evolutions, relationships, classifications, management, and sustainable uses, taxonomic studies provide highly relevant and vital knowledge and expertise.Three thousand eight hundred eighty-six species of vascular plants have been identified in Bangladesh as a result of numerous taxonomic investigations (Hossain et al., 2022).
Since 1814, these investigations have been carried out in multiple forests, regions, small to large administrative territories, and small to moderate-sized The specific distribution and voucher specimens of the reported plant species are not included in nearly all large-scale Ahmed et al., (2009), Ahmed et al., (2008), Ahmed et al., (2008a), Ahmed et al., (2009), Ahmed et al., (2009c), Prain, (1903), Siddiqui et al., (2007a), Siddiqui et al., (2007b) or many small-scale Ara et al., (2007), Rashid et al., (2018), Rahman, (2013), Rahman, (2018), Uddin and Hassan, (2010), taxonomic publications on the flora of this country (Haque et & Rahman, 2023).Thus, it is imperative that more thorough floristic surveys be conducted, collecting data on the distribution patterns and voucher specimens of the plant taxa in the uncharted regions of this nation.Consequently, a thorough floristic study of the entire Sonaimuri upazila is urgently needed.The current study intends to explore and catalog the vascular flora of the Sonaimuri region.An inventory of the vascular flora of the Sonaimuri upazila, Noakhali district, has been made available for the first time in Bangladesh.

MATERIALS AND METHODS
The Sonaimuri region, rich in biodiversity, is situated in Bangladesh's Noakhali district.In addition, this area is rich in social, political, and economic conditions as well as in religious harmony, history, heritage, and education (Dash et al., 2020).The current upazila of Sonaimuri was formerly a part of the larger upazila of Begumganj.It was declared Sonaimuri Upazila in 2005 after being split off from Begumganj.Sonaimuri Upazila is a 169.14 sq km territory that lies between latitudes 23°02' and 23°06' north and longitudes 91°00' and 91°13' east.It is surrounded by the upazilas of Chatkhil on the west, Senbagh on the east, Begumganj, and Monoharganj (Comilla) on the south (Figure 1).The Dakatia is the main river of Sonaimuri Upazila, which is a tributary of the Meghna and enters the country at Bagmara in the Comilla district, coming from the Indian state of Tripura.

RESULTS AND DISCUSSION
A total of 360 angiosperm species classified into 284 genera and 87 families have been documented from the research area in this study.These species comprise about 9.26% of the 3886 plant species that have been reported from Bangladesh (Hossain et al., 2022).
The species' scientific name, vernacular name, family, plant group, and habit characteristics are listed alphabetically (Table 1).The number of species per square kilometer found in the study area is nearly comparable to that of the Teknaf Wildlife Sanctuary Uddin et al., (2013) (Figure 5).Sonaimuri is a semi-urban region where natural, planted, and cultivated plant populations coexist.Numerous anthropogenic activities, such as diverse plantation and agriculture programs implemented after recurrent vegetation clearing and habitat degradation, have significantly disrupted a significant portion of the study region.
Nonetheless, as this study lists, a number of plant species have been established in this region as a result of the introduction of numerous exotic species, mostly in semi-urban areas like gardens, campuses, roadsides, tourist destinations, etc., as well as the introduction of diaspores of various plant species from across the nation using a variety of biotic and abiotic agents.Dense vegetation covers some of the area, which is made up of roadside, agricultural fields, fallow lands, homesteads, woodlands, and gardens.The study area's biodiversity is under threat from a variety of anthropogenic activities, the most common of which are land grabs, agricultural expansion after vegetation clearance, infrastructure development, settlement, the collection of fuel wood and leaf litter, huge visits, and other anthropogenic activities.

CONCLUSION
Thus, we heartily urge the creation of a master plan aimed at reducing any significant risks to the area's vegetation and habitats as well as promoting sustainable growth, use, and preservation of its plant resources.This region's sustainable socioeconomic and ecological services will be enhanced by proper protection, conservation, and development of its dwindling natural resources, especially its biodiversity.

Figure 1
Figure 1 Map of the study area (source: Banglapedia)

Figure 4
Figure 4 Dominant vascular plant families of Sonaimuri upazila.

Figure 5
Figure 5 Comparison of plant species composition in the Sonaimuri area with the Teknaf Wildlife Sanctuary.

Table 1
List of Vascular Plants of Sonaimuri Upazila.

Table 2
List of ten dominant genera of Sonaimuri Upazila and Bangladesh's flora.