An Overview of the Determination of Biodiversity of Wetlands

Wetland ecosystems support rich and unique biodiversity. Biodiversity of a given ecosystem in general and wetlands in particular provide important insights to the ecological health of an area. The Ramsar Convention 1971 identified nine criteria for identifying wetlands of international importance. Out of the nine criteria, eight are linked to biodiversity of which three are based on sites of international importance for conserving biological diversity, two are specific for water birds, two are specific for fish, and one criterion for other taxa. Hence, determination of biodiversity of wetlands is of utmost importance. In order to understand that birds, fishes, amphibians, odonates, mammals, and aquatic plants were particularly selected as indicators of wetland biodiversity, the chapter discusses the different methodologies about determination of each of these taxa under different criteria as mentioned above. These methodologies will help various stakeholders in appropriate determination of biodiversity of wetlands of a particular area.

Changes of Land Use and Land Cover with the Diversity of Fishes, Aquatic Plants, and Bird’s Species at Wetland Ecosystem

Bangladesh is rich in wetland biodiversity with aquatic plants, fishes, and birds. Mohanganj Upazila is known as the capital of lower Bangladesh. The present study focuses on the changes of land use and land cover (LULC) with a diversity of species that are being least concerned (LC), vulnerable (VU), and endangered (EN). Over the last two decades, the wetland species of Mohanganj were gradually declined. Our results showed that 19 fish, 4 aquatic plants, and 7 bird species were LC in 2015. Among the fish and aquatic plant species, 6 fish species (Wallago attu, Ompok pabda, Channa punctate, Chitala chitala, Salmostoma phulo, and Corica soborna) and 2 aquatic plant species (Nymphaea nouchali and Nymphaea lotus) were VU during the dry and rainy season of 2017 and 2019, respectively. In the dry season of 2019, 4 fish species (W. attu, O. pabda, C. punctate, and Ch. chitala), 2 aquatic plant species (N. nouchali and N. lotus), and 7 bird species (Anas platyrhynchos, Ardeola grayii, Gyps bengalensis, Alcedo atthis, Phalacrocorax fuscicollis, Porphyrio porphyria, and Larus ridibundus) were EN. Among the species, W. attu, N. nouchaii, G. bengalensis, P. porphyria, and L. ridibundus were extremely endangered categories. Changes in LULC, the establishment of settlements for the increasing population, indiscriminate use of pesticides, environmental pollutions, and climate change are the potential reasons for declining trends of wetland biodiversity. Stern actions on land use policy, expansion of organic agriculture, bioremediation of industrial effluents, and adoption of sustainable environmental policies should be taken by the Government of Bangladesh for immediate conservation of wetland biodiversity.

Pesticide Use Practices and Effects on the Wetland Biodiversity of Ndop, North West Region of Cameroon

Aims: The aim of this study was to evaluate farmer’s pesticide use practices and their effects in the wetland of Ndop. Study Design: A cross sectional study was carried out from January to August 2019 in Ndop, North West Region of Cameroon. Methodology: Questionnaires were administered separately to 382 rice and 100 vegetable farmers, and descriptive statistics was used in analyzing the results. Specifically, the Chi-squared statistic was used to determine the nature of the relationship between the variables. Results: The results showed that most of the crop fields (95.6%) lack a buffer zone since most farms were adjacent to water bodies (0 ≥farm ≥1 m). Farmers (100%) washed and rinsed knapsack sprayers in nearby water bodies. A majority of the farmers (71.3%) burnt or threw empty pesticide containers in open fields, water bodies, or nearby bushes. Both rice farmers (83.5%) and vegetable farmers (100%) reported that pesticides kill non-target organisms (fish, frogs, toad, snakes, birds, etc.) resulting into a drastic population decline in the wetland. A majority of the farmers (85.2%) no longer do fishing in the paddy fields because of the frequent fish decline caused by pesticide usage. Clarias gariepinus constituted 56% of the fish species harvested from the paddy fields and a drastic population decline was observed by the farmers. The average fish catch per month was low (12.22 kg ± 7.47 SD) relative to the past when pesticides were not used during cultivation. There was a significant difference between training and environmental awareness of pesticides (X2 = 28.98, p = 0.001). Conclusion: These results indicate an urgent need for a post-pesticide registration management strategy to ensure a sustainable management and conservation of the wetland resources of Ndop.

Wetland Biodiversity Disturbance Evaluation Induced by a Water Conservancy Project in the Flooded Plain of the Huolin River Lower Reaches

The Huolin River is an important water supply source for the wetland located in western Jilin province, especially the river flooding in the lower reaches of the basin. In recent years, the degree of aridity and salinization of the wetlands has increased. To prevent the further deterioration of the ecological system, water conservancy projects and irrigation systems were constructed to ensure water safety. What effects on the ecological system and biological diversity were induced by all the measures and constructions is not clear. The “emergency project” of the water recession of the Huolin River is taken as example. In the analysis, the project is divided into two stages, five indicators for criteria tier were selected, and for index tier, 21 indicators during the implementation stage and 15 indicators during the operation stage were selected for constructing the analytic hierarchy process (AHP) model. By using expert scoring to determine the weight of each indicator, the impact index and degree of water conservancy of projects on biodiversity are calculated. The results show that at the level of the impact categories, ecological landscape is identified as a key influence factor. At the index level, the occupied area of the landscape type, the changes in patch number, the water conservation function, and the water purification quality are identified as corresponding key impact indicators. The biodiversity overall impact index is −23.45, which means the negative impact and the degree is medium to low. Meanwhile, for the implementation stage, the index is −51.58, which indicates a medium to low negative impact, while for the operation stage, the index is 33.66, which indicates a medium to low positive impact. These results are analyzed and scientifically evaluated and corresponding protection suggestions for the local area are proposed.

Diving Beetle (Coleoptera: Dytiscidae) Community Dissimilarity Reveals How Low Landscape Connectivity Restricts the Ecological Value of Urban Ponds

Context: Structural and functional connectivity, as subconcepts of landscape connectivity, are key factors in biodiversity conservation and management. Previous studies have focused on the consequences of connectivity for populations of terrestrial organisms, which may not be appropriate for aquatic organisms. Objectives: As landscape connectivity critically affects the potential value of ponds for biodiversity, here we used diving beetles (Dytiscidae), an indicator taxon of wetland biodiversity, to investigate how structural connectivity affects functional connectivity to aquatic invertebrates in an urban landscape. Methods: We assessed pairwise similarities of dytiscid community, i.e. the variation of species composition between clustered and isolated ponds in the Helsinki Metropolitan Area, Finland. We investigated how dytiscid community similarity is affected by Euclidean distances between ponds, as an indicator of structural connectivity. Results: We found that clustered ponds shared more species than isolated ponds. Dytiscid species community similarity responded negatively to increasing Euclidean distance between ponds. Effectively dispersing species were widely distributed across the landscape, while poor dispersers were scarcely distributed in the same landscape. Conclusions: Structural connectivity determines which species are able to disperse successfully, with poor dispersers restricted to well-connected ponds. The different responses of effective dispersers and poor dispersers to the same structural connectivity indicates that functional connectivity determines species composition. We recommend providing well-connected aquatic habitats in urban landscapes and the implementation of measures to reduce isolation of wetland assemblages. Even clustered ponds need dispersal from other habitats to ensure their contribution to urban biodiversity.

Status of biodiversity in wetlands of Biswanath District of Assam, India

Kakati R, Das N, Bhuyan A, Borah D. 2021. Status of biodiversity in wetlands of Biswanath District of Assam, India. Biodiversitas 22: 453-472. Reports on biodiversity of a region are the firsthand data to understand the assemblage, importance, and to follow conservation inputs. The present study was aimed to document and analyze the wetland biodiversity of Biswanath District of Assam, India. Data was collected from 27 wetland habitats from 2015-2019. A total of 235 taxa were recorded, of which 79 taxa (77 species, one variety, and one subspecies) were vascular plants, 83 water birds, 47 fishes, 7 amphibians, 18 reptiles, and 2 mammals. None of the plants and amphibians fall under any of the threatened categories as per IUCN Red List 2020. However, among the bird species, 2 species are assessed as endangered, 4 species as vulnerable, and 10 species as near threatened. Among the fishes, 2 are vulnerable and 3 near threatened. Among the reptiles one is extinct in the wild (EW), 3 endangered and 3 are vulnerable. Along with the checklist of the present biodiversity, past and present population trends, as well as earlier records from Assam of the threatened species, is provided. The results of this study can be used by stakeholders for species identification and as the baseline taxonomic account for future studies on the conservation of these wetland species in a global context.

Environmental Flow Releases for Wetland Biodiversity Conservation in the Amur River Basin

Flow regulation by large dams has transformed the freshwater and floodplain ecosystems of the Middle Amur River basin in Northeast Asia, and negatively impacted the biodiversity and fisheries. This study aimed to develop environmental flow recommendations for the Zeya and Bureya rivers based on past flow rate records. The recommended floodplain inundation by environmental flow releases from the Zeya reservoir are currently impracticable due to technical reasons. Therefore, the importance of preserving the free-flowing tributaries of the Zeya River increases. Future technical improvements for implementing environmental flow releases at the Zeya dam would improve dam management regulation during large floods. The recommendations developed for environmental flow releases from reservoirs on the Bureya River should help to preserve the important Ramsar wetlands which provide habitats for endangered bird species while avoiding flooding of settlements. The results emphasize the importance of considering environmental flow during the early stages of dam planning and the need to enhance the role of environmental flow in water management planning.