Natural and anthropogenic driving forces as key elements in the Lower Danube Basin–South-Eastern Carpathians–North-Western Black Sea coast area lakes: a broken stepping stones for fish in a climatic change scenario?

© 2020, The Author(s). Background: Climate changes influence the ecosystems and induce potential risks regarding the natural products and services; the human society should predict and adapt in time to these coming global challenges. This research highlights a possible fragmentation of some of the Lower Danube River Basin lentic ecosystems fish populations in a climate change scenario. Results: The studied climate change potential events will affect 18 fish species of economic interest and eight of conservation interest and will induce disorder in some of the Lower Danube specific type of fish communities. The studied area was identified as a significant hot spot regarding the fish fauna ecological status major hazard, in a possible climate change (heating–drought–water depth decreasing) sequence of potential future events. Primarily the southern lakes of the studied area can be negatively influenced by the decreasing of the lakes water quality and quantity, some of the spawning habitats will vanish, some habitats and species will disappear, suspended sediment and nutrient levels in water will increase, eutrophication phenomenon will increase, the hydrological connectivity will diminish, fish associations’ structure will significantly change, etc. Conclusions: The climate changes trend in the Lower Danube Basin will affect the studied lakes ecological state and associated fish communities; mitigating measures are urgently needed. The future potential relative isolation of researched lakes by the surrounding hydrographical nets, for safety reasons of human communities or to convert inland areas should be banned specially for the lakes: Balta Domnească, Razelm, Tăbăcărie, Siutghiol, Taşaul, Tatlageac, Sinoe, Potcoava, Snagov, Comana, Victoria Gheormane, Dunărea Veche, Oltina, and Bugeac. Some of the researched lakes should be managed as wetlands of international importance and as important stepping stone areas for the fish fauna of the Danube Basin: Snagov, Comana, Victoria Gheormane, Dunărea Veche, Oltina, and Bugeac

Assessment of the ecological sustainability of river basins based on the modified the ESHIPPOfish model on the example of the Velika Morava basin (Serbia, Central Balkans)

This study examines the ecological sustainability of the Velika Morava River Basin (Serbia, Central Balkans) under modern conditions of multiple freshwater stressors, including climate change. The impact of stressors on the ecological services of the river basin is considered, including: drinking water, irrigation, recreation, tourism, ecotourism, and fishing. In order to assess the ecological sustainability of the river basin, a modification of the ESHIPPO model was performed. The essence of the modification is a change to the ES component, which, in the basic model, assesses the degree of ecological specialization of a taxon; and in the modified assessment of the ecological stability of the ecosystem (ESE). The structure of ichthyocenosis is used as the basic biological indicator for the assessment of ESE. The assessment of river basin sustainability was obtained as the difference between ESE and the impact of multiple factors, including: habitat change, invasive species, pollution, human population growth (social factors), and the over-exploitation of resources (HIPPO). The statistical analysis (SOM—Self Organizing Map) highlights the most reliable indicators of both biotic (ichthyocenosis structure elements) and the indicators that best detect the influence of HIPPO factors. The structure of the model is based on general and easily measurable indicators, which enables its application in any river basin in the world. The results of the model indicate that 80% of the studied basin is ecologically unsustainable and that its potential environmental services are greatly reduced