Macroinvertebrate assemblages in mountain tributaries of glacial-fed and rain-fed rivers in eastern Nepal

While river macroinvertebrates are the most widely used form of bioindicators, their baseline information, although crucial, is scarce in Nepal. The main objective of this study was to assess the macroinvertebrate assemblages in mountain tributaries of the glacial-fed Tamor and rain-fed Kamala rivers. A total of eight sites were sampled during March 2015 (Spring), November 2015 (Autumn), January 2016 (Winter), and May 2016 (Summer). Altogether, 49 Families of macroinvertebrates belonging to 15 Orders were identified with 39 Families and 12 Orders in Tamor’s tributaries, and 33 Families and 10 Orders in Kamala’s tributaries. Non-metric multi-dimensional scaling (NMDS) revealed different assemblages between the two river systems. The most dominant Order in the Tamor was Ephemeroptera and it was Trichoptera in the Kamala. EPT (Ephemeroptera Plecoptera Trichoptera) assemblages were the most abundant in all four seasons for both the river systems and higher % EPT in Tamor’s tributaries indicate better water quality than in the Kamala tributaries. Typical cold water adapted Families such as Rhyacophilidae and Stenopsychidae were observed in Tamor’s tributaries whereas in Kamala’s tributaries, warm water adapted Families like Naididae and Thiaridae were found, reflecting a difference in the abiotic variables such as temperature, dissolved oxygen attributed to each of the catchments. This baseline data can serve as the foundation for further bioassessment including those of climate change impacts on aquatic biodiversity.

Natural and anthropogenic changes threatening the ecological and limnological integrity of Lake Baringo, Kenya: A Review

Lakes are characterized by dynamic responses to ecological and limnologic disturbances that occur within a constrained timeframe. Some endorheic lakes in the Kenyan Rift valley are presently regarded as environmental hotspots because of complex changes that are revealed through multiple proxies; changing lake levels and surface area, turbidity and sedimentation, proliferation of macrophytes and loss of aquatic biodiversity. Lake Baringo is characterized by widespread catchment degradation accompanied by high levels of turbidity during erratic and decline of native fishery based on Oreochromis niloticus baringoensis. A careful analysis implicates potential natural factors such as catchment topography and increasing anthropogenic pressure as the main causes of lake ecosystem degradation. This paper recommends several strategies for restoration of Lake Baringo based on an integrated multi-faceted approach which combines catchment rehabilitation, pollution control and provision of alternative livelihoods such as agriculture to the riparian communities.

Forest Water Use is Increasingly Decoupled from Water Availability Even During Severe Drought

Context: Key to understanding forest water balances is the role of tree species regulating evapotranspiration (ET), but the synergistic impact of forest species composition, topography, and water availability on ET and how this shapes drought sensitivity across the landscape remains unclear.Objectives: Our aims were to quantify (1) the effect of forest composition and topography including elevation and hillslope gradients on the relationship between ET and water availability, and (2) whether the relationship has changed over time. Methods: We used remotely sensed Landsat and MODIS ET to quantify forest ET across the Blue Ridge ecoregion of the southeastern USA. Then quantified metrics describing ET responses to water availability and trends in responses over time and assessed how these metrics varied across elevation, hillslope, and forest composition gradients. Results: We demonstrated forest ET is becoming less constrained by water availability at the expense of lateral flow. Drought impacts on ET diverged along elevation and hillslope gradients, and that divergence was more pronounced with increasingly severe drought, indicating high elevation and drier, upslope regions tend to maintain ET rates even during extreme drought. We identified a decoupling of ET from water availability over time, and found this process was accelerated at higher elevations and in areas with more diffuse-porous trees. Conclusions: Given the large proportion of forests on the landscape distributed across high elevation and upslope positions, reductions in downslope water availability could be widespread, amplifying vulnerability of runoff, the health of downslope vegetation, and aquatic biodiversity.

Microplastics increase susceptibility of amphibian larvae to the chytrid fungus Batrachochytrium dendrobatidis

Microplastics (MPs), a new class of pollutants that pose a threat to aquatic biodiversity, are of increasing global concern. In tandem, the amphibian chytrid fungus Batrachochytrium dendrobatidis (Bd) causing the disease chytridiomycosis is emerging worldwide as a major stressor to amphibians. We here assess whether synergies exist between this infectious disease and MP pollution by mimicking natural contact of a highly susceptible species (midwife toads, Alytes obstetricans) with a Bd-infected reservoir species (fire salamanders, Salamandra salamandra) in the presence and absence of MPs. We found that MP ingestion increases the burden of infection by Bd in a dose-dependent manner. However, MPs accumulated to a greater extent in amphibians that were not exposed to Bd, likely due to Bd-damaged tadpole mouthparts interfering with MP ingestion. Our experimental approach showed compelling interactions between two emergent processes, chytridiomycosis and MP pollution, necessitating further research into potential synergies between these biotic and abiotic threats to amphibians.

Determinarea schimbărilor mediului acvatic, evaluarea migrației şi impactului poluanților, stabilirea legităților funcționării hidrobiocenozelor şi prevenirea consecinţelor nefaste asupra ecosistemelor (abordări, oportunități, realizări)

This article reflects on the main issues addressed in the AQUABIO project in the context of international provisions for the prevention of the risk of pollution of aquatic ecosystems and the need to protect/restore aquatic biodiversity. The paper presents the applied innovative tools, project stages, applied research methods and equipment as well as the main results obtained during 2020, including changes taking place in the ecosystems of the Dniester and Prut rivers under the influence of anthropogenic (water capture, dams, exploitation of rivers for energy purposes) and natural factors (meteorological conditions), which put at risk the functioning of aquatic ecosystems and their capacity for self-purification.

Măsuri de întărire a capacității de adaptare la schimbările climatice a ecosistemelor acvatice

The current article presents a bibliographic overview of green infrastructures and their role in strengthening the adaptive capacity of aquatic ecosystems to the adverse effects of climate change (high temperatures, heavy rains, droughts). Different types of ecological infrastructures are presented: forest buffer strips, rain gardens, permeable pavement, drainage ditches; bioengineering structures for bank stabilization. Also the functions performed by green infrastructures to maintain ecosystem services were presented: mitigating the effects of floods, stabilizing banks, preventing landslides and water caused erosion, stormwater management, reducing the load of pollutants. For the implementation of this approach in the hydrographic basin of Dniester River or the Prut River a more detailed study is necessary on the state of habitats, identification of hotspot areas of aquatic biodiversity, particularly those species important for maintaining of ecosystem functions, highlighting of the areas at high risk of floods or erosion.