Assessing marginal wetland loss to agricultural expansions in the Lower Ogun River Basin of Southwest, Nigeria

Wetlands are significant to the environment and economic survival of people most especially in the rural areas of the tropical world; their sustainability is however threatened by agricultural drainages and demographic pressure. The detrimental influence of agricultural expansion on wetland loss was examined using both primary and secondary data. The primary data was collected through questionnaires administration and interviewing of hundred members of Fadama Users Group (FUG) (i.e. 10%). The secondary data included satellite images of 1972, 1984, 2000 and 2015 analyzed using GIS technique and corresponding census data by simple descriptive percentage method. The results revealed that marginal wetlands lost about; 3180.60 ha between 1972 and 1984, 1936.08 ha between 1984 and 2000 and 805.32 ha between 2000 and 2015, to farmlands intensification throughout the periods of study. Wetlands ecosystem was also expected to lose more ground as the population growth is unabated and, more so, with the projected farmlands growth of about 4730.04 ha i.e. about 36.36% in 2030; there is, therefore tendency for serious depletion of marginal wetlands in the future.

Volunteering for otter conservation in Nepal: communicating with local communities

Amongst three species of otters, the Asian Small-clawed Otter has not been recorded since Hodgson (1839). Since 1991, the Eurasian Otter has neither been photographed nor sighted in the country. Recently, the Smooth-coated Otter has been reported only from Bardia National Park and its west. In this chaotic situation, a volunteer project was initiated for otter conservation in Nepal three years ago. 1000 copies of an otter conservation awareness poster were printed in 2017 and a second set of posters in 2019. Posters were distributed to local communities while communicating with the local people along the way and during stays. Thus far, we have conducted awareness activities at selected sites in nine districts and four protected areas. Over three years, we have talked with more than 2000 local people about otters and disseminated more than 1300 posters. At all sites, local communities responded that they had not seen otters for 20 to 30 years or more and for the last 10 years, even in protected areas. However, there are hopes that the last scarce individuals or populations of otters remain at very few sites. Overfishing, river poisoning and pollution, hydropower dams and station construction, and sand and pebble extraction from rivers, are the major causes for depletion of otters in these areas. In the past, trapping by Tibetans for otter pelts and by nomads from the plains of Nepal and India were major causes for population declines. In conclusion, we convey a conservation message that humans must learn to co-exist with otters if the species are to survive.

Antimicrobial resistance of Escherichia coli isolated from irrigation waters in selected urban fields around Yamoussoukro lakes in Côte d'Ivoire

This study examined the distribution of Escherichia coli (E. coli) resistant to eleven antibiotics and possible relationships among physico-chemical parameters and these resistances. It was carried out over two years during four climatic seasons in five lakes of the Yamoussoukro lake system in Côte d'Ivoire. The physicochemical parameters of the lakes studied are temperature, pH, dissolved oxygen (DO), dissolved organic carbon (DOC), turbidity, nitrates, orthophosphates and ammoniacal nitrogen. A total of 744 water samples were collected from five (5) lakes belonging to the lake system, over a two-year period, during four dry and four wet seasons. Escherichia coli loadings were evaluated after isolation on specific chromogenic medium COMPASS ECC Agar and the susceptibility to antibiotics by the agar diffusion method. Physico-chemical parameters were evaluated according to international standards. The physico-chemical results showed that the nutrient contents evolved generally from upstream to downstream of the lake system, independently of the sources of pollution of five lakes of system. However, the lake B, in upstream of the lake system, showed levels of nitrate, orthophosphate and ammoniacal nitrogen often similar to the downstream lakes. This demonstrates a source of chemical pollution in this lake, which flows to lakes D and E, which are themselves subject to other pollution. Bacterial loads and bacterial resistance to antibiotics have strictly evolved from upstream to downstream of the system. Most isolates were resistant to ampicillin (16.46%), tetracycline (12.87%), ciprofloxacin (12.86%) and sulfamethoxazole (10.14%). Antibiotic resistance patterns of E. coli isolates were similar in both years studied, but higher during rainy seasons (GRS and SRS). The spearman rank correlations and the principal component analysis (PCA) revealed significant correlations between bacterial resistance to antibiotics in lakes and water physico-chemical parameters. Turbidity and DOC can help to determine the main resistances in the lake D. Orthophosphates can help to understand the resistance of chloramphenicol and the nitrates can help to understand the resistance of ampicillin in the lake B. Resistance in the lakes A, B and C can be influenced by dissolved oxygen. Overall, this study provided baseline information on bacterial resistance in the lakes of Yamoussoukro in Côte d'Ivoire, showing that these lakes could be reservoirs of antibiotic resistance, potentially dangerous to public health.

Ramsar sites in Nepal: Conservation, present scenario, biodiversity value and threats

Wetlands are the dynamic ecosystems with high yielding capacity which are considered very prolific from view point of biodiversity. With prime functioning of water supply, wetlands are well known for supplementary functions of providing ecosystem services viz., groundwater recharge, carbon sequestration, preventing water logging and flooding etc. Total ten wetlands sites of Nepal are included in Ramsar List till 2019, Koshi Tappu being the first listed wetland and Lake Clusters of Pokhara Valley being the latest included wetland which covers 60,561 hectares area of the total area of the country. Ramsar sites in Nepal are distributed throughout the country and are classified as high altitude wetlands, mid hill wetlands and terai wetlands. The Ramsar Site hosts endemic species of floral species some of which are endangered. It too serves as excellent habitat as water hole and corridor for numerous digits of threatened and endangered faunal diversity. Besides this, they serve as excellent habitats for migratory birds as well. Being such integral portions of biosphere, wetlands are under constant threats like eutrophication, siltation, invasion of alien species, pollution, agricultural runoff etc. This review article is based upon desk review different published and unpublished literatures from national level and provides detail information on updated wetlands of international importance of Nepal, along with present scenario, biodiversity value and threats that the wetlands are facing and is expected to help in shaping future course actions for wise use and sustainable management of wetlands in Nepal.

Distribution of Metals along Simiyu Wetland of Lake Victoria Basin and its Impact on Agriculture

More than 70% of communities living along Simiyu wetland area are agriculturalists and pastoralists. Physical land degradation and poor nutrient mobility within the soil-plant system have shown a notable impact on agricultural production. Cycling of selected and their impact on agriculture were investigated along Simiyu wetland. Cation Exchange Capacity (CEC) of the soil was studied with respect to soluble cations and selected trace metals. To study the longitudinal and spatial distribution of the selected metals along Simiyu wetland, samples (water, sediments and soil) were taken in three stations along the river namely Bariadi Bridge, Simiyu Bridge and the Simiyu River mouth. Sampling of soil was done at different distances from the river so as to study the flow pattern of the metals and hence to explain the direction of cycling. Sampling was done both inn wet and dry seasons to study the seasonal variation of the metals. Geographical Position System was used to locate the sampling points for soil and water/sediment. Metals Chromium (Cr), Lead (Pb), Zinc (Zn), Coper (Cu), Cadmium (Cd) and Manganese (Mn) analyses were analyzed by atomic absorption spectrophotometer (AAS). High levels of Manganese and Zinc were detected in most samples with different distribution behavior between water and sediments that may reflect difference in solubility of metals in water or possible complex formation of the metals resulting to potentially less solubility of metals, hence retarding their bioavailability to plants low cation exchange capacity. Retarded nutrient mobility in clay soils was observed facilitated by the formation of hard pans resulting to less availability of the nutrients to plants. The study suggests some ways in which farmers can improve soil cation exchange capacity and hence improve agricultural productivity. DOI: http://dx.doi.org/10.3126/jowe.v6i0.5967 J Wet Eco 2012 (6): 31-43

Environmental Influences on the Distribution of Mangroves on Bahamas Island

Mangrove forests provide valuable ecosystem services but are declining in many tropical locations. The abundance of mangrove species in coastal fringe forests is related to biotic processes such as species succession or competition and abiotic factors, including nutrient availability, physiochemical water quality, soil composition, and tidal inundation. We examined the abundance of Rhizophora mangle and Avicennia germinans relative to environmental factors, including porewater chemistry, soil substrate, and distance from the ocean, on Bahamas Island. In this system, R. mangle were primarily found in litter-dominated soils and abundances were positively related to distance from the ocean, while A. germinans was only found in sandy soils closest to the ocean. Although phosphate, alkalinity, and salinity in porewater did not explain the distribution of species, free chloride varied significantly with distance from the ocean. These results suggest that soil conditions and tidal inundation may help determine the distribution of mangrove species on Caribbean islands. DOI: http://dx.doi.org/10.3126/jowe.v6i0.6081 J Wet Eco 2012 (6): 16-24

Traditional Fishing Methods of Bhutan

Traditional fishing techniques, practiced in all parts of Bhutan, are described and compared with techniques reported from Nepal. While a wide range of techniques is found in Bhutan, the number is significantly smaller than that from Nepal. For example, six kinds of net are reported from Nepal, but only one from Bhutan. However, the difference in number may reflect in part the limited scope of the present study. At the same time, several techniques appear unique to Bhutan, and others, while similar to their Nepali equivalents, use different materials - plant-derived poisons are an example. Some techniques may have been brought by ancient immigrants from Tibet, with more recent introductions from lowland India and, most recently, from Nepal. DOI: http://dx.doi.org/10.3126/jowe.v6i0.6081 J Wet Eco 2012 (6): 25-30

Plant Species Diversity and Composition of Two Wetlands in the Nairobi National Park, Kenya

Two wetlands (Hyena and Nalogomon) in the Nairobi National Park were investigated by comparing plant composition in and around their immediate vicinity. The most common aquatic plant species in the Hyena wetland was Cyperus dives while in the Nalogomon wetland was Typha domingensis. The terrestrial vegetation surrounding Hyena wetland dominated by while that of surrounding Nalogomon wetland was the grass Hyparrhemia rufa. It was also noted that Hyena Dam waters were colonized by aquatic weeds, namely Gunnera perpensa, Enhydra fluctuans and Ludwigia abyssinica, that were absent in Nalogomon wetland waters. This could have been due to eutrophication of the waters of Hyena Dam as it originated from human settlements (city estates) outside the park boundary. DOI: http://dx.doi.org/10.3126/jowe.v6i0.5909 J Wet Eco 2012 (6): 07-15

Assessment and prioritization of community soil and water conservation measures for adaptation to climatic stresses in Makawanpur district of Nepal

Climate change is the global concern of our sustainable development whose impact is of great concern to humanity. In Nepal, we are already starting to become aware of recent changes and developing the mechanism to adapt. A study was carried out in Bramha Thakur Community Forest User Group of Makawanpur district with an objective of assessing and prioritizing adaptation options by local community using soil and water conservation measures on climate change. Primary data were collected from direct observation, focus group discussion, key informant interview, preference ranking and transect walk. Meteorological data on temperature and rainfall of 30 years was collected from government sources and climatic trend was analyzed. Prioritization of adaptation options was done using Index of Usefulness of Practices to Adaptation (IUPA) tool developed by Debels et al. (2010). Monthly maximum value of daily maximum temperature and minimum temperature has increased by 0.0461°C and 0.12°C respectively. Numbers of warm days are increasing. Annual precipitation has increased steadily whereas maximum five days and monthly precipitation trend is increasing at high rate, alarming to hazards induced by climate change. Local people were found very resourceful in using various adaptation practices to deal with impacts of climate change. IUPA scoring provided important rankings on the adaptation options. Conservation pond was highly prioritized for drought management. To adapt with flood, engineering structures with or without vegetation were highly used as adaptation option. Bamboo plantation was highly preferred by local community to reduce the impacts of landslide and to prevent its occurrence. Bioengineering structures are highly recommended for long term stability in flooded and landslide affected areas. Further studies on adaptation options and their prioritization in more areas are recommended for comprehensive database and generalization. DOI: http://dx.doi.org/10.3126/jowe.v6i0.6997 J Wet Eco 2012 (6): 44-51