Naslov
The influence of local and catchment scale variables on the distribution of Salvinia natans and Trapa natans in channels in Eastern Croatia

Autori
Kočić, Aleksandra ; Jelaska, Sven D. ; Horvatić, Janja

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Aquatic Weeds 2009, Proceedings of the 12th European Weed Research Society Symposium / Pieterse, Arnold ; Rytkönen, Anne-Mari ; Hellsten, Seppo - Helsinki : Finnish Environment Institute, 2009

ISBN
978-952-11-3499-9

Skup
12th European Weed Research Society Symposium

Mjesto i datum
Jyväskylä, Finska, 24.08.2009. - 28.08.2009

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
Trapa natans; Salvinia natans; local scale; catchment scale; Eastern Croatia

Sažetak
In this research we have surveyed two different lowland areas in Eastern Croatia with the aim of improving understanding of the distribution of two conservationally important species, namely Salvinia natans and Trapa natans. Baranja, the north part of this region, is mainly agricultural land with a developed drainage network and partly a wetland area, while the Bosut River Basin, the southern part, is considerably covered by forest, with a dense network of rivers. As explanatory variables we used channel morphology and land use on the two landscape scales. Site characteristics of channel and species distribution data were gathered in the field at 249 sites during 2005 and 2006, while catchment data: the proportion of land use, total drainage length, total upstream area and drainage density were collated in frame of the Geographic information system (GIS). The influence of groups of variables at different scale on the distribution of macrophytes was analysed with multiple regression analysis. Variance inflation factor analysis was used to eliminate environmental variables that are collinear. Distribution of Salvinia was geographically predominant in the northern part of the investigated area and was mainly explained by the nearness to the wetland and the proportion of wetland in catchments, while the measured local physical variables were less important for its distribution. In contrast, distribution of Trapa was spatially predominant in the southern part of the research area and was mainly explained by the width of the channels. Catchment variables were less important, but the positive relationship with the total upstream area confirms the relation of the Trapa distribution to the wider rivers with the large catchment areas in Eastern Croatia. Results obtained for Salvinia confirm the importance of wetlands as the source of colonisation for macrophytes and the importance of wetlands conservation as a condition for the survival of rare macrophytes. The higher proportion of urban land use has a negative influence on the distribution of both species. It indicates the importance of including additional variables such as water quality data and other anthropogenic factors that could explain the influence of urban land use on aquatic systems. Results of our study indicate that macrophytes respond to their environment at different scales. Inclusion of the catchment scale variables gives us better insight into ecological processes. Therefore, different thematic and spatial scales should be taken into account in species distribution analyses with the aim of achieving predictive models adequate for conservation issues.

Izvorni jezik
Engleski

Znanstvena područja
Biologija

POVEZANOST RADA