Every water-course is a complicated system which consists of technical and natural elements. The number of these elements and the connections between them are little-known. The aim of the studies was to evaluate the effect of chosen system elements on the aquatic plant communities on the bottom. Longitudinal profile, bottom width, watercourse depth, substrate, level of bed silting, inclination of the slopes, slope protection and the time from the last interference in watercourse’s bed (regulation, maintenance works) were the chosen system elements. The basis of this paper were field studies, which were carried out in 13 small lowland watercourses in the Lower Silesia during the vegetation season in year 2007. For estimating the results of the studies, the rough sets theory was used. On this basis the hierarchy of the influence of elements of the water-course’s bed on the makrophyten communities was determined. ...
This paper presents the evaluation of the risk factors in the watercourses which will be regulated or maintained in the future. The analysis concerns one of the components of the ecological risk – the risk of the qualitative and quantitative changes by the aquatic plant communities. The basis of the analysis were field studies, which were carried out during the years 2007-2008 in six lowland water-courses in the Lower Silesia. On the river beds there were executed regulation or the maintenance works. The field studies comprised identification of aquatic plant species and es-timation of their cover-abundance. For the abundance analysis we used the Braun-Blanquet Scale. At the natural transects the number of aquatic plant spe-cies ranged from 4 to 7, and abundant from 5 to 100% of the bottom surface. At the altered stretches the number of aquatic plant species ranged from 0 to 5. The plant abundant did not exceed 25% of the bottom surface. On the ground on these dates were prepared a maps of ecological risk, which can be used in planning and execution on watercourses regulation and maintenance works. ...
This paper presents the ecological risk factors related to the watercourses regulation and maintenance works on the small and medium-sized lowland water-courses found in Lower Silesia. These factors include: occurrences related to the execution of regulation and maintenance works, which have an impact on the eco-logical condition of the watercourses, probability of these occurrences and their consequences in the form of adverse ecological changes in the river beds. Based on the observed responses of aquatic vascular plants species to the technical inter-ference on a watercourse's bed, a detailed assessment of one of these factors - ecological changes in the watercourse's bed was made. Field studies were con-ducted during 2007-2008 on 44 sections of various unregulated, conserved and regulated watercourses. Research included identifying the species of aquatic macrophytes found in the streambed as well as determining the degree of cover-age.The field studies showed, that the regulation and maintenance works had an adverse impact on the aquatic plant species composition. In most cases species removed during the technical interference did not regenerate. In some transformed study sections the plant species abundant was lower than on the unregulated tran-sects. Only in rare cases the plant species abundant in the compared study sec-tions was ...
This paper presents an assessment on the ecological status of various low-land watercourses found in Lower Silesia, determined by using aquatic macro-phytes as the primary biological indicator on the health and condition of such wa-tercourses. Field studies were conducted during 2007-2008 on various unregulated, conserved and regulated watercourses. Research included identifying the species of aquatic macrophytes found in the streambed as well as determining the degree of coverage. On this basis was the RI index calculated and the ecological status of watercourses defined.The field studies showed, that the watercourse's ecological status depends on many factor. To identify those factors we analyzed the correlation between the class of watercourse's ecological status and technical parameters like: bottom width, watercourse's depth, inclination of the slope and longitudinal profile. The analysis showed that the impact of channel parameters on the ecological condition of watercourses was similar in the case of natural watercourses and those that were transformed as a result of technical interference. However based on the survey cannot be found, that the technical parameters of watercourse's bed shaped as a result of regulatory and maintenance works affect the improvement or the dete-rioration of the ecological status. This follows from the fact that the ...
