Watershed Ecology and the Environment最新文献

Morphometry helps in understanding the behaviour of drainage characteristics with respect to various hydrological processes including infiltration, runoff, erosion and sediment transport. Morphometric analysis of river basins is an essential technique to the study the response of drainage basin in response to topological characteristics. The river basins' morphometric analysis is an important technique to prioritize the watersheds for implementation of soil and water management strategies. In this study, the morphometric characteristics of the lower Sutlej River have been determined using the geo-spatial techniques. The river basin, having area of 8577 km², was delineated into the fourteen sub-watersheds (WS-1 to WS-14) in the GIS environment. The ALOS PALSAR DEM and ArcGIS were utilized to evaluate the morphometric parameters of the delineated watersheds. The calculated morphometric parameters were used to rank the watersheds in terms of soil erosion potential. The priority ranks to the watersheds were assigned as per compound parameter, which was calculated by averaging the ranks designated to each morphometric parameter. Watersheds with the lowest compound parameter values were given the highest priority rating, and vice versa. Based on the results WS-7 was assigned the first rank whereas WS-13 was assigned the 13th rank. The principal component analysis was performed to determine the highly correlated morphometric parameters. Out of the 18 parameters, 13 were found be highly correlated. The compound parameter obtained based on these highly correlated parameters also prioritized WS-7 as the most vulnerable watershed. Therefore, WS-7 should be selected for the implementation of soil and water conservation strategies. It can be concluded that morphometric analysis along with PCA in combination with GIS can be helpful in prioritizing the watersheds in terms of soil erosion vulnerability and water management.

Deltamethrin (DM) is a pyrethroid insecticide, widely used worldwide, and is known to be toxic to diverse aquatic organisms. This work intended to evaluate the ecotoxicological effects of DM in Daphnia magna. To calculate the LC₅₀ and EC₅₀ values, an acute bioassay was conducted with a range of DM concentrations (0.1-150 µg/L). A chronic bioassay was also performed with a range of DM concentrations (18.66-100 ng/L). In both assays, a negative and a solvent control (acetone) were also tested. Life history parameters (reproduction and growth) were evaluated. Biochemical quantifications were also assessed regarding antioxidant and biotransformation capacity, oxidative damage, neurotoxicity, energy reserves content, and genotoxicity. LC₅₀ values and confidence interval at 95 % (CI₉₅) were 64.13 (CI₉₅: 46.40–81.85) and 65.22 (CI₉₅: 43.17–87.27) μg/L, and EC₅₀ values were 0.68 (CI₉₅: 0.54–0.81) and 0.31 (CI₉₅: 0.23–0.39) μg/L, for 24 h and 48 h, respectively. Regarding life-history parameters, only the lower DM concentration tested (18.7 ng/L) induced a significant increase in the rate of population increase (r). A significant increase in the solvent control was recorded for N1 fecundity, reproductive output, and r. Biochemical effects were only observed in terms of antioxidant/detoxification mechanisms (18.7, 32.6, 100 ng/L and solvent control) and oxidative damage (>18.7 ng/L and solvent control) but did not show an evident pattern of oxidative stress promoted by DM. Depletion of energy reserves (glycogen content) was observed from the lowest concentration tested as well as for the solvent control, and DNA damage up to 100 ng/L of DM was also observed. Future investigations (e.g. ecotoxicological studies with exposure of other aquatic organisms to environmentally relevant concentrations for longer exposure periods) would be required to confirm DM’s toxicity under ecologically relevant conditions. Moreover, the solvent effects in an ecotoxicological approach must be clarified.

This systematic review analyzes ecosystem services assessments and challenges at the national level of Ethiopia. The articles were downloaded from Google Scholar and Science Direct. Using the Boolean theory in the selected search engine, the number of articles downloaded was 78, but only 54 met the criteria. The output indicated that approximately 45% of the analyzed articles were performed in the forest ecosystem. But urban greening, groundwater-dependent ecosystem, and national parks are Ethiopia's most miniature researchable ecosystems. The most valued category of ecosystem services in the review article was the provision and regulation of services. The common methods used in researching the valuation process were simple estimation rather than standardized modeling systems. The other methods, such as benefit transfer, willingness to pay, choice experiments, bao game, and accounting of national systems, were standardized for estimating the ecosystem's economic value in selected articles. Based on the analysis, the value of the ecosystem services in Ethiopia showed a decreasing trend year by year. The most common drivers of ecosystem service change were land cover change, climate change, population growth, invasive species, insufficient attention from policymakers, and lack of sensitization of community and government authorities. Ignorance and lack of awareness about ecosystem services are enormous challenges for Ethiopia. Therefore, creating awareness for the community and government organizations must be the first task to restore and conserve all natural resources and ecosystem services.

Debris accumulation in natural ecosystems is one of several anthropogenic stressors exerting pressure on ecosystems all around the world. Effects of the ubiquitous anthropogenic debris pollution on free-living organisms is well known. Increasing reports of anthropogenic debris in nests of several species of birds ranging from terrestrial to seabirds are pouring in year after year. Shortage of natural nesting materials coupled with abundance of anthropogenic debris have been suggested the rationale behind the change in the nest building. Synthetic materials incorporated in nests can harm the occupants and negatively impact nesting and fledging success. As of late, majority of these studies are centred on plastic debris in bird nests. Here we present, a report of nest incorporation of metallic wire mesh in avian nests. 24 nests of Little egrets and 9 nests of Indian pond herons, totalling 33 nests in a heronry in India contained welded wire mesh. Though metal strips and wires in bird nests have been reported earlier, this could be the first report of inclusion of wire mesh in bird nests.

Over-summering is a phenomenon usually exhibited by migratory shorebirds. Those individuals that over-summer at their wintering grounds appear to be sexually immature or unfit to meet the risks of migration. Documentation of such migratory shorebirds are scanty along the Indian coasts and the present study focused on recording the over-summering shorebirds at five sites (Kappad Beach, Korappuzha Beach, Elathur Beach, Ariyallur Beach and Kadalundi-Vallikkunnu Community Reserve) along the west coast of India during 2021–2022. Over-summering shorebird species were identified and documented once in a week using a binocular, a spotting scope and a 4 K high speed motion latest video camera. Six species of over-summering shorebirds (Lesser Sand Plover Charadrius mongolus, Greater Sand Plover Charadrius leschenaultii, Pacific Golden Plover Pluvialis fulva, Whimbrel Numenius phaeopus, Common Sandpiper Actitis hypoleucos and Ruddy Turnstone Arenaria interpres) were recorded from the five study areas and their abundance were observed to be declining during the study period.

Morphometric analysis and sub-watershed prioritising were carried out to ascertain the Ajay river basin's susceptibility to flooding. The whole Ajay river basin was divided into seven smaller watersheds, and a ranking algorithm was used to the morphometric features of these smaller watersheds to determine their prioritization rank. 13 distinct morphometric criteria of linear, relief and areal characters have been found and used to rank and priorities sub-watersheds, for critical analysis. Some morphometric parameters have a direct correlation with flood occurrence, whilst others have an indirect association with flood occurrence. According to their relative significance and impact on the floods, all parameters have been given weighted ratings. The basin with the lowest parameter value is placed first in the ranking. According to the results of the study, sub-watershed 7, which is located in the lower catchment of the Ajay river basin, is very vulnerable to floods. The findings of this research may be utilized as advice by competent authorities in the early stages of flood mitigation efforts, if necessary.

Intensified erosion threats are one of the major ecological problems ravaging global basins. To address this problem, it is crucial to identify erosion-prone areas at the sub-watershed level. In this study, a seven multi-criteria decision-making (MCDM) models ensemble was developed to prioritize sub-watersheds in the Anambra Basin based on erosion risk. The integration of the MCDM models with the Analytical Hierarchical Process and Geographic Information System with 23 geomorphometric parameters (specifically 12 linear, 6 shape, and 5 relief parameters), enabled a comprehensive ranking approach. The accuracy of the models was tested using normalised Spearman's rank correlation to compute a uniform sub-watershed ranking. The results revealed that the study area is a 7th order basin with drainage densities between 0.54 km/km² to 0.62 km/km², average peak flow between 88 m³/sec to 361 m³/sec, texture ratio between 2.54/km to 11.25/km, and mean basin slope values between 10.9° to 22.2°. Out of the eight sub-watersheds, as indicated by the MCDM models, H returned the highest aggregate rank (1st), making it the top priority for erosion risk mitigation while B ranked the least (8th) suggesting the presence of some environmental conditions that are less erosion prone. The top-ranked MCDM models, MOORA (multi-objective optimisation based on ratio analysis) and COPRAS (complex proportional assessment), show that they are the best options for managing erosion in the Anambra Basin. These findings offer prospects for sustainable erosion risk control at the sub-watershed level and a scientific basis for resource management for basins with similar characteristics around the world.