Seasonal dynamics of macrophyte abundance in two regulated streams

Abstract

This study analysed seasonal dynamics of macrophyte abundance in two perennial lowland regulated streams (Stream 1 and 2) in the Danube basin (Slovakia). Assessments of macrophyte abundance and environmental characteristics were accomplished 7 times during the vegetation period in 2005 within a 100 m long section. Statistically significant differences in total abundance of macrophytes as well as an abundance of macrophyte groups (hydrophytes, amphiphytes, helophytes) and Potamogeton nodosus were detected among months within the vegetation period. Abundance fluctuations for individual macrophyte groups and species were moderate in Stream 1 and much stronger in Stream 2. Only amphiphytes showed bimodal temporal distribution in Stream 1, but the abundance of this group was low, reflecting more or less random occurrence of species in vegetation period. Multiple linear regression revealed that water depths and air temperature are the most significant environmental variables affecting the seasonal pattern of total as well as dominating group abundance in Stream 1 and 2, respectively. In all cases, abundances are significantly influenced by the abundance of the respective group in the preceding month. Culmination time differed between streams for all macrophyte groups except helophytes. Total abundance culminated 0.57 month later in the Stream 1 compared to Stream 2.

Emergent wetland vegetation data recording: Does an optimal period exist?

“…Summer is an appropriate period for recording relevant relevés of the communities (mentioned above in parentheses) that formed more than 60% of the stands in hydrologically stable habitats (Appendix ). The optimal time for sampling emergent wetland communities varies along an elevation gradient, so in mountain regions it equates with the period of maximum development of macrophytes in Central Europe (Hrivnák et al., ).…”

“…The seasonal variability of emergent wetland communities is initiated by fluctuations in the abiotic component of ecosystems, such as changes in the hydrological regime (Casanova & Brock, ), air and water temperature (Hrivnák, Oťaheľová, & Gömöry, ), light availability, physico‐chemical properties of water and sediment (Svitok et al., ), etc. The factors mentioned above affect the survival, establishment, growth (Lacoul & Freedman, ; Lawniczak, Zbierska, Choiński, & Szczepaniak, ) and main reproductive process (Coops & van der Velde, ; Lacoul & Freedman, ; Leck & Schütz, ; O'Donnell, Fryirs, & Leishman, ) of wetland plants, so changes in them lead to pronounced changes in the floristic composition (Warwick & Brock, ), species richness (Wassen, Peeters, & Olde Venterink, ) and cover (Hrivnák, ; Hrivnák et al., ). The seasonal variability of emergent wetland communities is mostly a result of changes in the composition and cover of accompanying species because the abundance of dominant species varies in narrow boundaries during the growing season (Jenačković et al., ).…”

Relationship between plant life forms and ecological indices in a lacustrine ecosystem

“…flow and shading are of crucial importance for the development and productivity of macrophytes [25][26][27][28][29][30][31][32].…”

Sediment type rules the response of aquatic plant communities to dewatering in wetlands

“…We also focused on the response of plant species according to their documented affinity for water (i.e. hydrophytes, amphiphytes and helophytes; Brock & Casanova 1997;Lacoul & Freedman 2006;Hrivn ak et al 2009) and hypothesized that the resistance of established hydrophyte species (plants that are strictly aquatic in their vegetative phase) would decrease with increasing disturbance intensity (i.e. being highest on organic sediment, lowest on coarse sediment and intermediate on silty sediment).…”