International Journal of Ecology

This research aims to evaluate the water quality status and pollution load-carrying capacity of the Way Umpu River based on land use. This was carried out using the survey method by directly measuring the river water debit, pH, temperature, and dissolved oxygen (DO) on-site, taking the water sample to analyze the parameters of water quality such as total dissolved solid (TDS), total suspended solid (TSS), water color, turbidity, salinity, biochemical oxygen demand (BOD), chemical oxygen demand (COD), fecal coli, total coliform, and plankton in the lab, and monitoring the land use. The results showed that the use of land for illegal mining and the settlement of inhabitants in station-4 (ST-4) caused water pollution. Furthermore, based on Class III water use, the parameters in ST-4 exceeded the standards for TSS, color, and BOD, while other stations such as ST-1, ST-2, ST-3, ST-5, and ST-6 showed clean and good water quality statuses. It was also found that the pollution load-carrying capacity of the Way Umpu River has not yet been exceeded for Class III and the quality of the water may be improved when the river water debit increases. In addition, the plankton community structure on ST-1, ST-2, and ST-3 showed the number of species and individuals, and the diversity index was relatively high compared to ST-4, ST-5, and ST-6. It was concluded that the integrated evaluation was based on water quality status, plankton community structure, and pollution load analyses. The land use for illegal mining will decrease the water quality and the plankton community structure compared to other land uses.

Silphium perfoliatum (cup plant) is native to North America and is increasingly used as a bioenergy crop in Germany. Spontaneous occurrences of this species have already been detected in several European countries. To assess the possible risk to biodiversity by spreading of S. perfoliatum, we investigated the competitiveness of this species against the native and highly competitive Urtica dioica over four years in a field experiment in Bayreuth (Germany). S. perfoliatum grew well among U. dioica, although its biomass was strongly reduced by surrounding U. dioica. Projection area, plant height, and reproductive potential were less or similarly reduced by surrounding U. dioica as by the intraspecific competition. Moreover, S. perfoliatum significantly suppressed the growth of the competitive U. dioica. A settlement and establishment of S. perfoliatum in the native flora of Central Europe and a suppression of uncompetitive plant species are therefore conceivable.

Global warming is a serious world problem where earth’s temperature has been reported to increase over the years; the aquatic ecosystems are also not the exceptions. But, the effects of this phenomenon on the aquatic ecosystems are not well understood. This study aims to understand the influence of surface temperature on the population density of Limnothrissa miodon in Lake Kariba. We constructed a mathematical model on the population dynamics of Limnothrissa miodon with nutrients, phytoplankton, zooplankton, and Hydrocynus vittatus. Lake surface water temperature was modelled by a cosine function, and the parameters were estimated from data fitting. Numerical simulations were used to determine the stability of the nonautonomous model. Numerical simulation results of the nonautonomous model showed a stable periodic orbit for varying initial conditions, and therefore, instability. Numerical techniques were used to investigate the influence of surface water temperature on Limnothrissa miodon. Results from the model with fitted lake surface water temperature data showed that a shift in the optimal temperature for phytoplankton growth from C to C, corresponding to dominance of Cyanophyceae over Chlorophyceae, resulted in a decline in the population density of Limnothrissa miodon. Numerical results showed that the population density of Limnothrissa miodon declines after an optimum temperature of C for phytoplankton growth. Numerical simulation results suggested that warming of the lake may lead to a decline in Limnothrissa miodon population density in Lake Kariba.

Wetlands are valuable resources that provide a variety of functions for local populations, including environmental, hydrological, and socioeconomic benefits. Despite the importance of wetlands to humanity, they have been largely degraded and even lost in many countries including Ethiopia because they are wrongly regarded as wastelands. Some wetland conservation policies were designed not based on the perceptions of the people residing around the wetlands and lack of attention to communal areas. It is because of this gap that a quantitative analysis of physicochemical soil quality analysis and the local community’s perceptions was carried out with the overall goal of analyzing the degradation status of Kadar-Basaso wetland and community perceptions. A cross-sectional research approach was used with a purposeful soil sampling from/in 6 plots sized 50 m × 50 m and >100 m apart along two transect lines, and 200 household heads chosen randomly from three villages(Basaso, Shallo, and Nano Robe) bordering the wetland. Soil sampling, questionnaires, focus group discussion, and key informant interviews were used to collect data and then examined quantitatively and qualitatively. The result shows that the Kadar-Basaso wetland was moderately degraded. The physicochemical analysis of the soil reveals that the pH was acidic, indicating the presence of acidic waste effluents. In addition, the electric conductivity was salt-free, cation exchange capacity were found to be low, the organic matter was relatively low, potassium levels vary very little, and Phosphorous variation was minimal. Expansion of farmland and Overgrazing were the most damaging elements affecting wetland biodiversity. From the analysis, it was noted that communities’ attitudes influence human activities on the wetland. The study recommends that the government and wetland management authorities must establish strategies to minimize deterioration in the area and offer better infrastructure for both livestock keepers and farmers to improve the long-term usage of wetlands. The best management strategies should be devised for all sizes, types, and all site wetlands.

The study aimed to estimate the physical and monetary values for nontimber forest products (NTFP) of the Surra government plantation in the upper Hare-Baso rivers catchment of Gamo highlands, southwestern Ethiopia. The Surra government plantation was established in the mid-1980s and consisted of C. lusitanica, E. globulus, and P. radiata tree species, which were planted side by side. Because of food insecurity, forest proximity communities/inhabitants relied on extracting NTFP such as litter and fodder for income and livestock feed despite none of them being physically and monetarily accounted for. The plot method and stock change approach were applied to determine sample plots and collect litter data, respectively, while the active market price was used to account for monetary correspondences. Fodder data were acquired via integration of animal unit month (AUM), livestock carrying capacity, animal unit equivalent (AUE/TLU), quality of pasture (poor), and proper use factor (30%). Its monetary price data were collected from the local market. The gross total production of litter and grass/fodder was 158,614.90 kg and 284,076 kg per/year, respectively, while the corresponding monetary values were ETB 206,169.40 and ETB 255,669, respectively. However, the “proper use factor”-based physical value of fodder/grass was 85,224 kg per/year, and its corresponding monetary value was ETB 76,701. The average physical value (volume) of grass production/year during the wet and dry seasons was 56.67 kg and 96.67 kg, and its mean monetary price/kg was ETB 1.4 and 1.2, respectively. It was concluded that the fodder/grass data collected via the integrated approach reduced the accounting errors, and the data were more precise. Accounting for the economic values of litter and fodder embedded in the market price upscaled the accounting quality and was more indicative of ground facts. Therefore, this study contributed a fresh accounting approach to the field of NTFP accounting.

This study estimated the technical efficiency of small-scale trawling in the Mekong Delta using a translog stochastic frontier production function model. Primary data were collected by interviewing the small-scale trawling vessels from January 2020 to May 2021 in the four coastal provinces (Soc Trang, Bac Lieu, Ca Mau, and Kien Giang) of the Mekong Delta. The results showed that the average technical efficiency of the surveyed fishermen was approximately 68.8%. Small-scale trawling vessels could increase their production by 31.2% if they operated at full technical efficiency. The captain’s fishing experience, vessel size, the number of nets on a boat, cooperation for inputs, supplies, and problem-solving, fishing registration, operation distance, and the fishing grounds were the main factors influencing the technical efficiency. To improve the technical efficiency of the trawling industry, it is necessary to focus on training the captains in fishing techniques, upgrading and converting large-scale vessels, and linking the market channels for consuming the caught fishery products.