Bacterial Microbiomes in the Sediments of Lotic Systems Ecologic Drivers and Role: A Case Study from the Mureş River, Transylvania, Romania

Numerous sections of the Mureş River vary in terms of the abundance of nitrates, ammonia, and orthophosphates; and of correlated lotic sediment bacterial microbiome structures in terms of both diversity and abundance. This highlights the great versatility of microbiomes in being influenced by the physical-chemical characteristics of environments and their spatial changes. Bacteria microbiomes exhibit dynamic and shifting potential and significant tendencies toward self-organization and self-adaptation. These typical features represent an essential ecologic basis for lotic systems having to do with the use and reuse of various kinds of environmental resource as chemical substances. In this respect, trophic processes assure the river ecosystem optimum health ecologic status dynamic and trend, to be reached. The flexibility of shifting bacterial microbiomes is crucial in maintaining this ecological context’s vital role in biogeochemically sustaining other taxonomic groups, which are spatially and temporally continuous. This is especially important for nutrient cycle processes, even for rivers with high levels of negative human impact, in promoting a functional lotic system.

The Role of Aquatic Refuge Habitats for Fish, and Threats in the Context of Climate Change and Human Impact, during Seasonal Hydrological Drought in the Saxon Villages Area (Transylvania, Romania)

In spite of the obvious climate changes effects on the Carpathian Basin hydrographic nets fish fauna, studies on their potential refuge habitats in drought periods are scarce. Multiannual (2016–2021) research of fish in some streams located in the Saxon Villages area during hydrological drought periods identified, mapped, and revealed the refuge aquatic habitats presence, management needs, and importance for fish diversity and abundance for small rivers. The impact of increasing global temperature and other human activities induced hydrologic net and habitats alteration, decreased the refuge habitats needed by freshwater fish, diminished the fish abundance, and influenced the spatial and temporal variation in fish assemblage structure in the studied area. The sites more than one meter in depth in the studied lotic system were inventoried and all 500 m of these lotic systems were also checked to see what species and how many individuals were present, and if there is was difference in their abundance between refuge and non-refuge 500 m sectors. The scarce number of these refuges due to relatively high soil erosion and clogging in those basins and the cumulative effects of other human types of impact induced a high degree of pressure on the fish fauna. Overall, it reduced the role of these lotic systems as a refuge and for reproduction for the fish of downstream Târnava Mare River, into which all of them flow. Management elements were proposed to maintain and improve these refuges’ ecological support capacity.

Proposed Environmental Risk Management Elements in a Carpathian Valley Basin, within the Roşia Montană European Historical Mining Area

Non-ferrous metals mining activities have long accompanied people, and began in the study area of South East Europe over 2000 years ago. The environment quality is significantly affected by both historic mining activities and contemporary impacts. All these problems, inducing synergic negative effects on local organism communities, have created a chronic state of pollution. The Corna Valley has one of the oldest historical human impacts in Romania due to the influence of mining. Fish and benthic macroinvertebrates have exhibited significant responses to long term mining effects on lotic systems. The analysis of macroinvertebrate communities, correlated with the lack of fish and some biotope characteristics, indicates that the Corna River presents a variety of categories of ecological status between sectors. The lack of fish reveals the poor ecological conditions. Technical and management solutions are proposed here to diminish the historical environmental problems and to avoid future ecological accidents, especially in an attempt to improve any construction plan concerning a possible new de-cyanidation dam and lake. Fish and benthic macroinvertebrates have exhibited significant responses to long term mining effects on lotic systems. Two management zones were identified, an upper zone which can be used as a reference area and a lower zone, where pollution remedial activities are proposed.

Neotropical otter diet variation between a lentic and a lotic systems

Neotropical otters have been scarcely studied at the northern edge of their distribution in Mexico. The species has nocturnal-twilight habits, and their principal food is fish and crustaceans. The aim of this work was to know the foraging habits of Neotropical otters (Lontra longicaudis) in two monitoring sites one lentic and the other one lotic systems of the Río San Lorenzo, Sinaloa México. From February 2009 to January 2010, we surveyed the area during the four seasons by walking 15 km of the river edge of Río San Lorenzo, and 15 km at the El Comedero reservoir. We collected 318 scats, 155 in the reservoir and 163 in the river. Fish were the most abundant prey item in both places, with a frequency of occurrence of 98.1 % in the river and 100 % in the reservoir. The percentage of occurrence varied largely in the other prey items in both places. Seven taxonomic groups compose their foraging habits in the river (relative frequency in parentheses): fish (64.3 %), insects (9.2 %), mollusks (6.8 %), birds (6.0 %), mammals (5.6 %), crustaceans (5.2 %) and fruits (2.8 %). Five taxonomic groups in the reservoir compose it: fish (65.1 %), birds (22.7 %), mammals (9.2 %), fruits (2.5 %) and insects (0.4 %). The most important fish in the diet belonged to the genus Oreochromis, which includes an introduced species. We conclude that the Neotropical otter is an opportunistic carnivore that preys mainly on fish, probably due to their high availability, but they also forage in other taxa that are available at Río San Lorenzo basin.

Flora of Ceará, Brazil: Cabombaceae

The present study analyzed taxa of the family Cabombaceae occurring in the state of Ceará. Only Cabomba species was represented, with C. aquatica and C. haynesii recorded in the state. Populations occur in permanent and temporary lentic environments, such as lagoons and shores of lotic systems. This work presents taxon identification keys, morphological descriptions, illustrations, comments and geographic distribution data.

Odonata (Insecta) species richness in the Parque Estadual do Ibitipoca, Southeast Brazil

There are few studies on Odonata communities in Brazil, even in its most deeply studied states, such as Minas Gerais. Therefore, it is proposed the presentation of results on the Odonata species richness of Parque Estadual do Ibitipoca (Ibitipoca State Park), located at the Zona da Mata region in the Minas Gerais state, Brazil. This Conservation Unit is considered a priority area for the conservation of the state’s invertebrates. The objective of this study was to know the number of species within the area. 100 hours of sampling were carried out, distributed amongst five campaigns of four consecutive days between November 2016 and July 2017. There were recorded 20 different species, including a new record for the state and one potential new species. Species richness was low due to the sampling being focused exclusively on lotic systems, and also to the environment’s homogeneity. Despite the low number of species, Parque Estadual do Ibitipoca is relevant to the conservation of the Minas Gerais state’s Odonata.