Categorization of the flora and fauna: A study from the Uttara region, Dhaka, Bangladesh

Flora refers to the plant life or vegetation found in a particular region or ecosystem. It includes all plant species ranging from the smallest mosses and ferns to towering trees [1]. Eventually, flora plays a vital role in the ecosystem, as it supports the food chain, contributes to the oxygen cycle, and helps to maintain the balance of nature. The study of flora, known as floristics, involves identifying and classifying plant species, studying their distribution and relationships, and understanding their ecological and evolutionary significance [2]. Floral diversity plays a crucial role in maintaining the ecological balance of an ecosystem. Each plant species is part of a complex web of interactions between other species, including pollinators, herbivores, and predators [3]. Unlike a wide variety of plants, the ecological system as a whole may go out of balance, which might have disastrous consequences for the environment and the organisms that rely on it [4].

Numerous attempts to study flowers have been made during the past few decades. Bangladesh has already conducted surveys and documented the plant species in on-premises areas of several universities [5-7]. Although, the Uttara region displayed a diversification of plants. However, no floristic study was conducted on the Uttara region. With 165 million citizens, Bangladesh is among the most populous countries in the world [8] and its population is now growing at a pace of 1.22%. Deforestation is a critical issue in Bangladesh. The country's forest cover has been drastically reduced over the past few decades due to logging, agricultural expansion, and illegal encroachments [9]. The loss of forests not only diminishes biodiversity but also disrupts water cycles, increases soil erosion, and contributes to the loss of livelihoods for many communities dependent on forest resources [10]. Carbon sequestration and nutrient dynamics constitute fundamental elements of ecosystem functionality [11]. Plant communities act as carbon sinks, absorbing carbon dioxide from the atmosphere and mitigating the effects of climate change. In addition, diverse plant communities can help regulate local climates by providing shade, reducing temperatures, and maintaining humidity levels [12]. In this scenario, plant resources are crucial for providing food, medicine, and other necessities. Nonetheless, it is regrettable that plant resources are disappearing globally, especially in Bangladesh (IUCN, 1990), and that this is a danger to farmland, the ecosystem, and the woodland [13].

In the center of Dhaka, Bangladesh, the Uttara region is a multicultural and active neighbourhood. The study area having incredible flower diversity, which gives the surroundings a special charm and beauty, is one of its most prominent qualities. The area is covered with a variety of trees, shrubs, and flowers that create a lush, green landscape and offer a welcoming setting for people. The goal of this research study is to examine the flora and fauna at the Uttara region by identifying the different plant species and exploring their ecological and monetary value. Hence, there is a high demand for enhanced knowledge in eco-friendly and cost-efficient methods to promote diverse plant population, maintain environment quality, and secure global food safety free from toxic substances [14]. The study will also provide insight into how the locality protects and preserves its unique plant history, including how it uses sustainable plantations.

Study Location

Uttara region is in the northern part of the capital of Bangladesh, Dhaka City at the bank of river Turag. Uttara region Uttara Thana (Dhaka metropolitan) area 36.91 sq km, located in between 23'51' and 23'52' north latitudes and in between 90'22' and 90'24' east longitudes. Of 9 m beyond the average sea level [15]. The Uttara region Uttara Thana (Dhaka metropolitan) comprises an area of 36.91 sq km (Figure 1). To guarantee the plant resources of plant communities at the Uttara region for this study, a field investigation was carried out.

Physiographic and soil condition of the study region

Uttara region lies under the Agro-ecological Zone - Modhupur Tract (AEZ 28), and it has a wet tropical climate having an average yearly temperature of 29.96°C (85.93°F), 9.9 inches of rainfall per year, and 65.8% mean yearly humidity [16]. Reddish brown clay soil with a pH ranging from slightly acidic to extremely acidic makes up the soil types in these places. The soil analysis reveals that both the total content of one nutrient and the concentration of organic matter are at low to moderate levels. There are low levels of another nutrient and an essential trace element [17, 18]. The study area is mentioned in   Figure 1.

 Collection and compilation of data

A field survey was carried out (Table 4). The fallow land (plain), pond side bank, roadside, waterbody, roof-top, etc. were all recognized as potential flora habitats. Data were collected from August 2021 to October 2022. The study was of basic methodological approaches and surveys. Data were taken separately followed by local name, scientific name, area of collection, collection time, habit, habitat, family, and collector’s name attached with each data collection sheet. Most of these habitats were dispersed and intertwined throughout the study regions. We included every area that was accessible for the survey because the goal of the study was to find the full range of plant diversity in the study region. All kinds of witnessed plant species, including herbs, shrubs, trees, climbers, native and exotic species, cacti, orchids, and others, that were present in the habitats were recognized and named in the field.

Identification of the collected specimens and data analysis

With the use of published journals and textbooks of reference, Bengal Plants [19], Encyclopedia of Flora and Fauna of Bangladesh [20, 21], Trees of Bangladesh [22], Medicinal Plants of Bangladesh [23], and Red Data Book of Vascular Plants of Bangladesh [24] the unidentified samples were recognized.

Number of plant species under different categories and habits

The comprehensive study of plant species in the Uttara region revealed a diverse floral community, categorized into Table 1, ornamental, fruit, vegetable, spice, medicinal, wood, plantation, and field crops, representing 39.11%, 16.44%, 16.0%, 4.44%, 12.44%, 2.22%, 3.11%, and 6.22%, respectively. Plants were further classified based on growth habits into trees (28.0%), shrubs (16.0%), herbs (43.55%), and climbers (12.44%). Ornamental plants predominated, followed by fruit and vegetable species, with timber plants showing the lowest density highlighting a trend towards urban gardening and ornamental horticulture [25, 26].

Distribution of family, genus, and species

The comprehensive documentation of plant species in the Uttara region highlights rich biodiversity, with a total of 225 plant species categorized into Table 2, ornamental, fruit, vegetable, spice, medicinal, timber, plantation, and field crops. The ornamental plants dominate, comprising 36.13% of the total families, followed by fruit plants at 20.16%, vegetables at 10.92%, spices at 5.04%, medicinal plants at 16.80%, timber at 3.36%, plantation crops at 1.68%, and field crops at 5.88%. In terms of genera, there are 89, 31, 25, 8, 25, 4, 7, and 14 for each respective category, and species count at 88, 37, 36, 10, 28, 5, 7, and 14. This diversity underscores the significance of ornamental plants in enhancing the campus landscape and supporting local biodiversity.

Plant families with the percentage

The comprehensive documentation of plant species in the Uttara region stated in Figure 2 reveals Fabaceae as the largest plant family, comprising 7% of all species. Following Fabaceae, Amaryllidaceae accounts for 4%, making it the second-largest plant family, with Cucurbitaceae, Moraceae, Rutaceae, and Solanaceae also contributing significantly to the floral diversity. Families such as Brassicaceae, Compositae, Euphorbiaceae, and Malvaceae each represent 3% of the total plant families, while Apocynaceae, Caesalpiniaceae, Combretaceae, Lamiaceae, Liliaceae, Palmae, Rubiaceae, and Zingiberaceae each account for 2%. The remaining 44% of plant families are represented by single species, highlighting a considerable presence of rare or less common families. This extensive diversity aligns with previous studies [27, 28], emphasizing Fabaceae's ecological and agricultural significance, particularly in nitrogen fixation and soil fertility [28, 29].

Fruit plant species under each family

The study recorded in Table 3 a total of 37 fruit tree species from 23 families in the Uttara region. The Rutaceae family had the highest number of species, with 6 species accounting for 16.21% of all fruit-producing plants. The Moraceae family followed with 4 species, representing 10.81% of the fruit tree species, while the Myrtaceae and Anacardiaceae families each contributed 3 species, making up 8.10% of the total fruit tree species. In contrast, only one species was found in several families, including Annonaceae, Caricaceae, Malvaceae, and Sapotaceae. These findings highlight the dominance of the Rutaceae family, consistent with its known diversity and economic importance, particularly in the cultivation of citrus fruits.

List of flora of Uttara region with their respective common names, scientific names, family, and plant type

Plant genetic resources represent a wide range of plant species essential for upholding global food security and agricultural resilience [30]. The extensive variety of plant genetic resources highlights their importance in agricultural research, breeding initiatives, and conservation endeavors focused on preserving biodiversity and promoting agricultural sustainability [31]. The enumeration of the botanical species presented in the Uttara region, inclusive of their corresponding colloquial nomenclature, taxonomic designations, families of various fauna specimens stated in Figure 3, and plant type-based categorization was presented in Table 4.

Ornamental plant species under each family

This study recorded a total of 88 ornamental plant species from 43 families in the Uttara region. The Compositae family had the highest number of species, with 7 species making up 7.95% of all ornamental plants. Following Compositae, the Apocynaceae family comprised 6 species, contributing 6.81% to the ornamental plant diversity.

Vegetable plant species under each family

The examination of vegetable plant species at Uttara region revealed a total of 37 species classified into 13 families, highlighting the significant diversity present stated in Table 6. The Cucurbitaceae family emerged as the most abundant, containing 9 species, which constitutes 24.32% of the overall vegetable plant species. Following closely, the Amaranthaceae family ranked second with 7 species, underscoring its importance in providing nutrient-rich leafy vegetables essential for food security.

Spices of plant and field crop species under each family

Six families of spice plants included a maximum of 11 species in Table 7. The greatest number of species were found in the Zingiberaceae family, accounting for 3 and 27.27% of all spice plants, respectively (Table 7). Amaryllidaceae, Lauraceae, and Solanaceae together make up 18.18% of all species of spice plants. A minimum of one plant species from the Rutaceae and Apiaceae. This study identified a total of 14 field crop species across seven families, with the Fabaceae family leading the count with six species, representing 42.85% of all field crops. Following closely, the Poaceae family contributed three species, accounting for 21.42%. The remaining families, including Cruciferae, Lamiaceae, Pedaliaceae, Solanaceae, and Tiliaceae, had minimal representation, collectively making up only 7.14% of the total. In parallel, the study also identified 11 species of spice plants from six families, where the Zingiberaceae family, with three species, constituted 27.27% of all spice plants.

Medicinal plant species under each family

This study documented in Table 8 a total of 29 medicinal plant species across 20 families, with the Lamiaceae family showcasing the highest diversity, contributing four species, which represents 10.50% of all medicinal plants. The Combretaceae family followed, with three species accounting for 10.34% of the total. Families such as Acanthaceae, Asteraceae, Fabaceae, and Malvaceae each contributed two species, collectively making up 6.89% of the total. Individual species were also identified from families including Annonaceae, Boraginaceae, Cucurbitaceae, Dioscoreaceae, Euphorbiaceae, Labiatae, and Zingiberaceae, highlighting a diverse array of medicinal resources Table 8.

Timber plant and plantation crop species of Uttara region, Dhaka under each family

A maximum of 5 spice plants was seen in 4 families of trees. The greatest number of species discovered belonged to the Mimosaceae family, which made up 2 and 40% of all woody plants, respectively. The Boraginaceae family, followed by the Fabaceae and Maliaceae, account for 20% of all species of timber plants, which is the least amount Table 9. The study identified a total of seven spice plant species across six families, with the Palmae family exhibiting the highest diversity, comprising four species, which account for 57.14% of all plantation crops. The Arecaceae family followed closely with three species, representing 42.86% of the total. Additionally, five spice plant species were documented across four families of trees, where the Mimosaceae family emerged as the most prevalent, encompassing two species and making up 40% of the woody plants. The Boraginaceae, Fabaceae, and Maliaceae families contributed one species each, together constituting 60% of the overall timber plant species Table 9.

List of Fauna identified from the study area

The present survey findings displayed a variety of insect pests that were observed during the investigation Table 10. These pests appeared from several orders and families, highlighting the wide variety of insects that can endanger plants and crops. The list starts with widespread insects including White Fly (Trialeurodes vaporariorum) and Mealybug (Ferrisia virgata), that are infamous for infesting different plants and weakening them by consuming sap. The Leaf miner (Tuta absoluta), with larvae we found that tunnel through foliage and cause damage and decreased plant vitality is another serious pest. The commonly seen Common Fruit Fly (Drosophila melanogaster) is a noticeable presence because it contaminates ripening fruit, causing deterioration and monetary losses. Pests like Field Cricket (Gryllus sp.), Yellow stem borer (Scirpophaga incertulas), and Brown plant hopper (Nilaparvata lugens), which eat plant tissues or spread disease, can seriously harm crops like rice, also prevail in the present study. The survey revealed the pests unique to certain crops, such as the Rice root weevil (Sitophilus oryzae) and Rice gundhi bug (Leptocorisa spp.), which can severely harm rice grains. The Giant water bug (Lethocerus americanus), albeit not a significant agricultural pest, was also described as being present in rice fields.

The floristic survey of Uttara region reveals a rich and diverse array of plant species, underscoring the ecological and socio-economic significance of urban green spaces. This study identified 225 plant species across 119 families, demonstrating a considerable botanical variety that can significantly contribute to urban biodiversity, ecological resilience, and the local economy. The presence of ornamental, fruit, and medicinal plants highlights their role in enhancing urban biodiversity and providing essential ecosystem services. Ornamental plants, such as those from the Compositae and Apocynaceae families, add aesthetic value and support urban wildlife by providing habitats and food sources for various pollinators. Integrating diverse plant species in urban planning can enhance ecological balance, mitigate urban heat island effects, and improve air quality.

The lower density of timber plants, reflective of urbanization and changing land use priorities, emphasizes the need for sustainable urban development that incorporates diverse plant species to maintain ecological resilience and promote biodiversity in densely populated areas like Dhaka [32]. The presence of key families like Moraceae, Myrtaceae, and Anacardiaceae underscores their ecological and agricultural value, contributing to ecosystem services and biodiversity [33, 34]. The substantial presence of fruit and medicinal plants indicates significant opportunities for educational and research endeavors in horticulture and pharmacognosy. Families such as Amaryllidaceae and Brassicaceae are notable for their diverse applications in food production and traditional medicine. For instance, plants from the Moringaceae family, including Moringa oleifera, are celebrated for their therapeutic properties, such as anti-diabetic, anti-inflammatory, and antioxidant effects [35]. Similarly, the Combretaceae family, with plants like Terminalia, is known for its potent antioxidant and antibacterial compounds [36]. These findings highlight the potential for utilizing these plant resources in developing new pharmaceuticals and enhancing nutritional health.

The variety of vegetable and spice plants identified in the study offers opportunities for culinary and nutritional studies, contributing to dietary health and agricultural economics. The prominence of families such as Solanaceae and Amaryllidaceae, which include staples like chili peppers and garlic, underscores their importance in local cuisine and food security [37]. Additionally, the presence of underutilized crops from families like Apiaceae and Dioscoreaceae suggests potential for expanding crop diversity and improving agricultural resilience [38]. The representation of timber and plantation crops points to avenues for agroforestry research. The substantial presence of the Palmae family, with economically important plants like coconut and oil palm, underscores their vital role in agriculture and economic development [39]. These findings align with previous studies emphasizing the role of plant diversity in promoting sustainable agricultural practices and supporting local economies.

The discovery of numerous rare plant families enhances overall biodiversity, essential for ecological resilience and research opportunities. The minimal representation of families like Annonaceae and Caricaceae suggests areas for potential expansion in cultivation and research, as these families may include species with unique traits beneficial for diversifying fruit production and improving crop resilience [40]. This detailed inventory of plant species serves as a foundation for future studies aimed at optimizing urban horticulture and promoting sustainable agricultural practices. Continued research and monitoring are essential to understand the dynamics of plant populations and their interactions with urban environments. Implementing conservation strategies and sustainable management practices can help preserve plant diversity and ensure the long-term ecological health of urban areas.

The report also highlights the prevalence of various insect pests that pose significant threats to crop production. Effective pest management strategies are crucial to protect plant productivity and minimize financial losses. The diversity of pests identified, including the whitefly, mealybug, and rice green leafhopper, underscores the need for targeted control measures and integrated pest management practices. By focusing on pests that affect multiple crops, the study emphasizes the broader challenge of managing pest populations across various agricultural sectors. Implementing effective pest control measures can enhance crop yields, reduce economic losses, and contribute to sustainable agricultural practices.

The current study found that there are 225 different plant species, 119 families, and 203 different genera present in Uttara region. A total of 88 species of ornamental was categorized into 89 genera and 43 families (one was rare and endangered). Spice plants were displayed in ten species, with eight genera and six families each. Fruits were divided into 37 families, 37 genera, and 37 species. There were 36 species of vegetables divided into 25 genera and 13 families. A total of 5 species of timber plants were grouped into 4 genera and 4 families. Twenty families and twenty genera made up the 28 medicinal species. The plantation crops included 7 species, 7 genera, and 2 families. 14 species and 14 families made up the field crop. Many plant categories have a variety of behaviors, as well as a variety of species, genera, and families, and some insect pests are also observed. The variety and quantity of plant species in the study area showed a strong floristic diversity. The campus area has the potential to become a premier hub for the preservation of biological variety with the right management tactics, adoption of crucial laws, and conservation activities. This study offers important insights into the floral variety of the Uttara region and sets the groundwork for future ecological studies and conservation efforts.

SKR and MN conceived the research plan and improved the methodologies. NQC, ZSA, SM, JS, JN, IAI, and FA contributed to the survey. MN and FR conducted the data analysis and table preparation and wrote the manuscript. SKR, FB, PKM, and MOS did the manuscript review and edited the manuscript. All the authors approved the final version of the manuscript.

The authors are grateful to the Bangladesh Forest Research Institute and the International University of Business Agriculture, and Technology (IUBAT).

There is no conflict of interest among the authors.