~ 45 ~ International Journal of Fisheries and Aquatic Studies 2021; 9(3): 45-55 E-ISSN: 2347-5129 P-ISSN: 2394-0506 (ICV-Poland) Impact Value: 5.62 (GIF) Impact Factor: 0.549 IJFAS 2021; 9(3): 45-55 © 2021 IJFAS www.fisheriesjournal.com Received: 22-03-2021 Accepted: 24-04-2021 Shourav Dutta Department of Forestry and Environmental Science, Faculty of Biological Science, Rangamati Science and Technology University, Rangamati, Bangladesh Pinaki Chowdhury Department of Environmental Science and Disaster Management, Noakhali Science and Technology University, Noakhali, Bangladesh Tusher Kumer Ray Bangladesh Forest Research Institute, Chattogram-4000, Bangladesh Sanjoy Das Bangladesh Forest Research Institute, Chattogram, Bangladesh Md. Emdadul Hoque Bangladesh Forest Research Institute, Chattogram, Bangladesh Corresponding Author: Shourav Dutta Department of Forestry and Environmental Science, Faculty of Biological Science, Rangamati Science and Technology University, Rangamati, Bangladesh Biodiversity of the Medir Haor wetland ecosystems of Bangladesh Shourav Dutta, Pinaki Chowdhury, Tusher Kumer Ray, Sanjoy Das and Md. Emdadul Hoque Abstract Complex nexus between aquatic and terrestrial ecosystems, namely wetland has a significant environmental impact on the survival, breeding, nesting, and feeding of numerous floral and faunal species. A study was carried out in the Medir haor (MH) wetland ecosystems of Bangladesh to enumerate its vegetation coverage, faunal resources, and evaluate the impacts of biodiversity on the ecosystems as well as surrounding communities. A total of 76 plant species belonging to 66 genera, and 135 faunal species (12 invertebrates and 123 vertebrate species) were enumerated from the study area through extensive fieldwork following vegetation survey, faunal survey, interview, and Focus Group Discussion (FGD). Among the plant resources, herb was the dominant category (32 species, 29 genera) followed by tree (22 species, 18 genera), shrub (11 species, 9 genera), climber (3 species, 3 genera), and fern (2 species, 2 genera). Bird species were found to be higher (46%) in comparison to other faunal species in the study area. The study divulged that residents were dependent enormously on the natural resources of the MH wetlands. Though biological diversity has significant ecological and socio-economic importance on haor-dependent residents, natural resources seemed to diminish continuously from the haor area due to over-exploitation. This research recommended sustainable wetland management, awareness-raising among the residents, and policy implications to manage the biodiversity of the MH wetlands on a sustainable way. Keywords: Bangladesh, biological diversity, environmental sustainability, Medir Haor, wetland ecosystems 1. Introduction Wetlands, a combination of different aquatic and terrestrial conditions, are considered the most complex ecosystems of the world that harbor a huge variety of floral and faunal species and are of great ecological significance [1] . Wetlands are probably envisaged as the most important zone for inland freshwater fisheries because they support a large invertebrate fauna, act as a feeding ground for young and growing fishes, crustaceans, vertebrates, microbes, etc., and also provide a large variety of refuges against predators [1, 2] . Gradually, high varieties of major groups of animals and plants have greatly adapted to these mosaic ecological landscapes [3] . Wetland ecosystems can provide a huge ecological contribution to biodiversity, even demonstrating high levels of alpha and beta diversity, i.e., species diversity and turnover between habitats [4] . Wetlands are not only the habitats of several animals, but also the important sources of drinking water, sources of edible food, and often used by the migratory birds for breeding and resting [1, 3] . Meanwhile, wetland landscapes are the most feasible ecosystems for nesting, breeding, and survival of various fauna, i.e., amphibians, fishes, reptiles, invertebrates, microbes, etc. [1] . But, due to human influences and anthropogenic disturbances, wetlands are the most threatened and deteriorated ecosystems of the world nowadays [1, 3, 4] . Researchers reported that more than 50% of wetland ecosystems were disturbed and lost globally during the last century due to human interferences, specifically drainage, conversion, and collection of natural resources [5, 6] . Hence, the abundance of freshwater species is reducing tremendously from the biodiversity-rich wetland ecosystems [5, 7] . In a broader sense, wetlands are categorized as the interface between terrestrial and aquatic ecosystems, and sometimes one or more wetland types are combined to form a floodplain [8,9] . Bangladesh, located in the northeastern part of South Asia, possesses a rich biological heritage