Biological control of invasive zebra mussel (Dreissen polymorpha) in a freshwater ecosystem through Potamon ibericum

In the present study, possible effects of using Potamon ibericum for the prevention of zebra mussel (Dreissena polymorpha) invasion in a freshwater ecosystem were investigated. In a recirculating aquaculture system (RAS) supplied with aerated freshwater, 3 individuals of P. ibericum were placed in each of 3 aquariums provided by 100 zebra mussels. Throughout the 90-day monitoring study, mussel consumption was visually counted and then new mussels were introduced daily to complete the number of mussels to hundred, repeatedly each day. Throughout the monitoring study, growth rates, number of mussels consumed, and the number of broken mussel shell pieces were determined. Daily consumption rate of mussels by each crab was recorded as 11.115, 11.104, and 11.107 mussel/crab in the 3 experimental groups, respectively. The consumption rate of mussels per crab was counted as 999.78 over the 90-days experiment. As a result, the findings of this study provide strong evidence that P. ibericum can be used for

Response of Physicochemical and Microbiological Properties to the Application of Effective Microorganisms in the Water of the Turawa Reservoir

Effective microorganisms (EM) technology was used to find the optimal method of water restoration in the designated experimental area. The study aimed to evaluate the impact of EM biopreparation on selected physicochemical and microbiological properties using ISO methods. A week after the application of biopreparations, a slight decrease in the nitrates content (0.375–0.531 mg L−1) and a significant decrease in the content of phosphorus compounds (0.130–0.304 mg L−1) compared to the control date were observed. Moreover, on the second date, the decrease in most values of microbiological properties was noted. Two weeks after the application, in most cases, the values of water quality properties were shaped close to values obtained in the control date (before EM application). The EM effect was rather short-term, but optimization of application properties may prolong the effect and thus, include the EM technology among the best eco-friendly technologies used for freshwater ecosystem restoration.

Spatio-temporal evolution of glacial lakes in the Tibetan Plateau over the past 30 years

As the Third Pole of the Earth and the Water Tower of Asia, Tibetan Plateau (TP) nurtures large numbers of glacial lakes, which are sensitive to global climate change. These lakes modulate the freshwater ecosystem in the region, but concurrently pose severe threats to the valley population by means of sudden glacial lake outbursts and consequent floods (GLOFs). Lack of high-resolution multi-temporal inventory of glacial lakes in TP hampers a better understanding and prediction of the future trend and risk of glacial lakes. Here, we created a multi-temporal inventory of glacial lakes in TP using 30 years record of satellite images (1990–2019), and discussed their characteristics and spatio-temporal evolution over the years. Results showed that their number and area had increased by 3285 and 258.82 km2, respectively in the last 3 decades. We noticed that different regions of TP exhibited varying change rates in glacial lake size; some regions even showed decreasing trend such as the western Pamir and the eastern Hindu Kush because of reduced rainfall rates. The mapping uncertainty is about 17.5 %, lower than other available datasets, thus making our inventory, a reliable one for the spatio-temporal evolution analysis of glacial lakes in TP. Our lake inventory data are freely available at https://doi.org/10.5281/zenodo.5574289 (Dou et al., 2021); it can help to study climate change-glacier-glacial lake-GLOF interactions in the third pole and serve input to various hydro-climatic studies.

Invasion and Dispersion of the Exotic Species Procambarus clarkii (Decapoda Cambaridae) in Yeongsan River Basin, South Korea

The introduction of exotic species negatively affects the distribution and interactions within local biological communities in an ecosystem and can threaten ecosystem health. This study aimed to provide the basic data required to manage P. clarkii in the Yeongsan River basin. We identified the dispersion pattern and evaluated the ecosystem risk of this newly introduced species. The distribution survey investigated Procambarus clarkii populations at 25 sites in the Yeongsan River basin over a four-year period. The initial introduction occurred in Jiseok Stream. The larvae of P. clarkii were most abundant in areas with a dense aquatic plant cover, whereas adults preferred silt/clay areas. The alterations in the water flow by the river refurbishment project (carried out in 2012) increased their preferred habitats and contributed to P. clarkii dispersion. However, stable isotope analysis showed that the dispersion has had little effect on the freshwater ecosystem. The interrelationship between P. clarkii (i.e., larvae and adults) and other biological communities has been limited. Although the rapid dispersion by P. clarkii in the Yeongsan River basin has not impacted the freshwater ecosystem, further ecological information is required on how to manage P. clarkii beyond this early stage of invasion.

Best Practices for Monitoring and Assessing the Ecological Response to River Restoration

Nature-based solutions are widely advocated for freshwater ecosystem conservation and restoration. As increasing amounts of river restoration are undertaken, the need to understand the ecological response to different measures and where measures are best applied becomes more pressing. It is essential that appraisal methods follow a sound scientific approach. Here, experienced restoration appraisal experts review current best practice and academic knowledge to make recommendations and provide guidance that will enable practitioners to gather and analyse meaningful data, using scientific rigor to appraise restoration success. What should be monitored depends on the river type and the type and scale of intervention. By understanding how habitats are likely to change we can anticipate what species, life stages, and communities are likely to be affected. Monitoring should therefore be integrated and include both environmental/habitat and biota assessments. A robust scientific approach to monitoring and appraisal is resource intensive. We recommend that appraisal efforts be directed to where they will provide the greatest evidence, including ‘flagship’ restoration schemes for detailed long-term monitoring. Such an approach will provide the evidence needed to understand which restoration measures work where and ensure that they can be applied with confidence elsewhere.

Helminths and helminth communities of Carassius gibelio (Bloch, 1782) from the Panicheri Reservoir, Aegean Water Basin, Bulgaria

Ecologoparasitological research was done based on the helminths and helminth communities of the Prussian carp (Carassius gibelio (Bloch, 1782)) from the freshwater ecosystem of the Panicheri Reservoir, Aegean Water Basin, Bulgaria. As a result of the examined nine specimens of the Prussian carp, two species of helminths were found: Ligula intestinalis (Linnaeus, 1758), larvae and Pomphorhynchus laevis (Müller, 1776). The dominant structure of the helminth communities was determined. The Panicheri Reservoir is a new habitat in Bulgaria of P. laevis and L. intestinalis from C. gibelio. C. gibelio is a new host record for L. intestinalis in Bulgaria. The two helminth species are core species for the helminth communities of the examined species of the freshwater fish. P. laevis was distinguished with higher prevalence and mean intensity (P%=33.34; MI=1.34) than L. intestinalis (P%=22.23; MI=1.0). The circulatory pathways of the helminth flow were traced.