Discovering the ecological structure of different macrophyte groups in rivers using non-parametric and parametric multivariate ordination techniques.

This paper analyses various methods of ecological ordering that are often used in modelling the relationship between vegetation and habitat. The results of direct gradient ordination by Canonical correspondence analysis (CCA), which is based on correlation, were compared with Non-metric multidimensional scaling (NMDS), which is based on rank analyses. Both tools were also compared with Detrended correspondence analysis (DCA), which is a popular indirect gradient analysis method. The macrophyte assessment was conducted at 98 river locations in the lowland regions of Poland. Each of the surveyed locations falls within a consistent abiotic category: small to medium-sized lowland rivers with a sandy bottom. Habitat elements analysed included limnological variables and geographic parameters, and the botanical survey focused on submerged macrophytes, including vascular plants, as well as bryophytes and algae. Firstly, it was shown that various analytical tools for determining the importance of ecological factors (Monte Carlo test, BIOENV) identify slightly different significant factors responsible for the development of macrophytes in rivers. Secondly, considerable similarity was found in the structure of macrophyte communities generated on NMDS and DCA biplots, while macrophyte communities were presented very differently based on CCA. Thirdly, the ecological preferences of aquatic plants based on one-dimensional analyses primarily reflected the results of CCA, whereas they did not always follow the ecological pattern revealed by NMDS. Finally, by conducting separate studies for non-vascular plants and vascular macrophytes, it was confirmed that different ecological drivers are responsible for the development of particular groups of macrophytes.

Urban visual pollution: comparison of two ways of evaluation-a case study from Europe.

Visual pollution by outdoor advertisements (OAs) of the urban landscape in the old town of Gniezno city (Poland) was the main aim of the presented work. For this purpose, the part of Warszawska Street located near the old market was selected. The detailed objective of the work was to evaluate the effect of OA on the building perception and compare two different methods to check the possibility of their interchangeably potential. The city audit and public opinion about selected buildings were performed. The photographs with and without OAs were also analyzed. The statistical analysis was performed to find the significant differences between these two methods and define differences between groups of respondents. In general, the results revealed the strong effect of the building quality (condition and appearance of the building) on the final score of the building perception. This was valid for both evaluation methods. The significant differences between building perception with and without OAs and groups of respondents were found only for the building with good facade quality. While, in the case of low-quality buildings the perception of the urban landscape was low regardless of the presence of OAs. Moreover, we can primarily conclude that city audit and survey of public opinion can be used interchangeably.