The quality of the aquatic environment and macrophytes of karstic watercourses

Abstract

The quality of the aquatic environment and macrophytes were surveyed in the case of the remarkable karstic river Ljubljanica s. lat. (Slovenia). It consists of seven intermittent and permanent surface watercourses, connected by groundwater flows. We assessed 11 parameters describing the land use beyond the riparian zone, the structure of the riparian zone and stream channel morphology, as well as the distribution and abundance of macrophytes. The intermittent watercourses exhibited a relatively high level of naturalness, because the variable water regime prevents intensive human activity. Greater influence of the human activity on the permanent watercourses resulted in a modified riverine environment. The share of different ecological groups of macrophytes, i.e. submerged, emerged and amphibious species, reflected the water regimes of the different watercourses. A total of 62 taxa of macrophytes were identified in about 100 km of length examined. Of these, amphibious macrophytes dominated as a consequence of intermittent water regime. The relationship between environmental parameters and macrophytes, and the effects of the intermittent hydrology were investigated. All environmental parameters explained 28% of the variance in the distribution of macrophytes in watercourses, as determined by canonical correspondence analysis. Completeness of the riparian zone, bank undercutting and sediment accumulation were found to be the most influential.

Macrophytic Distribution and Trophic State of Some Natural and Impacted Watercourses - Belgium Wallonia

“…This facies homogenization leads almost directly to a simplification of aquatic biota and a drastic decline in biodiversity and biomass [41 and 42]. At sites in this region, P. pectinatus is showing a high recovery rate (>30%), as has also been reported by the literature [42][43][44][45].…”

Photon-harvesting efficiency and arbuscular mycorrhiza in amphibious plants

“…During the summer dry period, plants grow on dry land. Due to water level fluctuations amphibious plant species prevail , Šraj-Kržič et al 2006a.…”

“…Alternation of floods and dry periods in intermittent aquatic habitats results in a unique flora, dominated by plants that are able to thrive submerged and emerged, the so called amphibious plants (Braendle and Crawford 1999, Šraj-Kržič and Gaberščik 2005, Šraj-Kržič et al 2006a. Their survival in ecosystem with frequent water level fluctuations depends on several adaptations such as heterophylly that can be induced by several environmental factors (Kuwabara and Nagata 2002).…”

Seasonal dynamics of macrophyte abundance in two regulated streams

“…Sparganium emersum behaved as hydrophyte in Stream 1, although it is frequently classified as an amphiphyte [e.g. 22,23]. Generally, it is a plant of still to fast-flowing watercourses with a moderate to high nutrient status growing in fine (silt-clay) sediment [e.g.…”