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Povzetek: Rivers are spatially and temporally heterogeneous systems that are susceptible to changes due to anthropogenic influences. These can significantly alter water quality and river communities, including macrophytes, which are involved in nutrient cycling, energy flow and sedimentation processes, and provide habitats for other organisms. The presence, abundance, and distribution of macrophytes can thus serve as indicators of the state of aquatic ecosystems. Rivers that flow (partially) underground are particularly susceptible to (human) impacts from the hinterland due to their lower self-purification capacity. Using a modified RCE (a Riparian, Channel, and Environmental Inventory) method, we classified the Rak River as first or second RCE quality class, and the Obrh River as second or third RCE quality class. According to the River Macrophyte Index (RMI), the ecological status of both rivers was moderate, good or very good, except for the first section of the Obrh, the status of which was assessed as poor. The ecomorphological preservation of both rivers and suitable conditions for macrophyte growth contribute to the high species diversity observed in both rivers: a total of 36 taxa were recorded in the Obrh and 38 in the Rak. In the latter, the presence of Myriophyllum verticillatum L. was recorded for the first time at the time of our sampling. Almost one third of the species in each of the rivers are listed on the Slovenian Red list of threatened pteridophytes and seed plants, supporting the evidence of their high naturalness and emphasizing the importance of appropriate management of karst watercourses.
Ključne besede: karst, macrophytes, RCE method
Objavljeno v DiRROS: 29.08.2024; Ogledov: 112; Prenosov: 160
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Ključne besede: developmental biology, karst aquifers, stygobionts, phylogeny, cave animals, Iran
Objavljeno v DiRROS: 12.07.2024; Ogledov: 212; Prenosov: 165
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Povzetek: Large-scale forest disturbances (LSFD) are an essential component of forest ecosystem dynamics. The effects of rapid loss of forest cover and other changes in forest ecosystems are inextricably linked to hydrologic processes such as evapotranspiration, soil and recharge processes. Among all hydrogeological systems, karst aquifers are important because of their exceptionally rich and unique biodiversity, biomass, and groundwater resources. At the same time, they are characterized by specific hydrological processes that make them highly vulnerable to environmental changes. Therefore, this study paid special attention to the effects of LSFD on karst hydrology. Using the PRISMA checklist, a thorough literature review of studies published between 2001 and 2020 was compiled into a comprehensive matrix dataset. In addition, an initial assessment of the global and regional distribution of forests on carbonate rocks was made based on publicly available geodatabases of forests and karst aquifers. The compiled information provides the first global overview of hydrological processes affected by LSFD, and identifies important knowledge gaps and future research challenges. The matrix dataset contained 117 full-text articles with a total of 160 case studies. Most publications were from 2011 to 2017, with more than half of the studies at the plot level and more than one-third at the catchment level. Studies on the effects of fires and pest and diseases infestations predominated. However, no articles were found on the effects of ice storms on hydrology in general or on the effects of pest and disease infestations on hydrology in karst areas. Of the 45.6 M km2 of forested land worldwide, 6.3 M km2 or 13.9% of all forests are underlain by carbonate rocks. Carbonate rocks cover about 15% of the land surface, which means that 31.3% of the world's karst aquifers are covered by forest. 29% of all case studies were conducted in karst areas, which is a high proportion compared to the proportion of forests in karst areas. However, these studies are unevenly distributed geographically. Most studies were conducted at the plot level, and only 21% of studies focused on natural LSFD, so forest management and land use change studies predominated. Although studies on the effects of LSFD on evapotranspiration processes between vegetation, air and soil are fairly well represented, infiltration and recharge processes in karst areas remain poorly understood and knowledge is lacking, particularly on groundwater flow and related hydrological processes. Regional studies and impacts on groundwater resources are also insufficient. The results indicate an urgent need for an integrated holistic interdisciplinary approach and a comprehensive understanding of the individual influencing factors, which would allow more accurate modelling of hydrological processes in forested karst aquifers.
Ključne besede: natural disasters, climatic changes, evapotranspiration, hydrology, karst aquifers
Objavljeno v DiRROS: 19.05.2023; Ogledov: 779; Prenosov: 356
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Ključne besede: forest fire, Slovenian Karst
Objavljeno v DiRROS: 13.12.2022; Ogledov: 867; Prenosov: 161
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Povzetek: Wood density and radial wood increment were examined in trees of pubescent oak (Quercus pubescens Willd.) and black pine (Pinus nigra Arnold., subsp. nigra) in relation to stand mixture and underlying bedrock. Trees of both species from pure and mixed stands were sampled across two types of bedrock, limestone and flysch. Trees from each species were similar in age. Wood density was estimated in standing trees using resistance drilling and increment cores were taken from a smaller subsample of trees of both species. Tree-ring, earlywood and latewood widths were measured and compared to radial profiles of wood density. The influence of stand mixture, diameter at breast height and bedrock on wood density was examined using a Bayesian general linear model. Wood density was significantly higher in pubescent oak than in black pine. Stand mixture was found to affect wood density positively, although the magnitude of the effect was relatively small when compared to other influencing factors also included in the current study. The effect of diameter on wood density was positive on both bedrocks in pubescent oak and negative or neutral in black pine. The size of the effect varied by bedrock and species. On flysch bedrock, the influence of diameter on wood density was stronger than it was on limestone. These indirect bedrock effects on wood density are probably a result of different soil fertility rather than the bedrock itself. There was a notable difference in radial wood increment in both species across the two bedrocks, whereas the differences in densities were smaller. Higher wood densities found on flysch in the subsample of pubescent oaks are likely an effect of higher proportions of latewood, while the opposite trend was observed in black pine. Higher wood density was found on limestone in black pine despite higher latewood percentages on flysch. In the context of forest management, the species composition of the naturally occurring mixtures in the sub-Mediterranean region should be adjusted slightly to favor pubescent oak, since it is a climax species and will bind more carbon for longer than black pine due to higher wood densities. Future forest management should also promote the overall development of pubescent oak trees in sub-Mediterranean stands. The results are especially important in the European context, because the share of sub-Mediterranean stands is expected to rise with global warming.
Ključne besede: Karst, wood structure, resistograph, resistance drilling, Quercus pubescens, Pinus nigra, limestone, flysch
Objavljeno v DiRROS: 14.01.2021; Ogledov: 1377; Prenosov: 583
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