Vegetative reproduction by species with different adaptations to shallow‐flooded habitats

Abstract

In shallow flooded parts of rich fens Mentha aquatica might thrive in deeper water than Epilobium hirsutum but previous experiments have provided no clear indication that the flooding tolerance of these species differs. In this study we investigated, by measuring growth, biomass allocation and vegetative reproduction, whether the impact of water level on vegetative reproduction might produce different lower boundaries on water level gradients. There was a striking contrast between biomass production at high water levels and the field distribution of both species. After 18 wk, the mean biomass of E. hirsutum grown in waterlogged and flooded conditions was 82% and 54%, respectively, of the mean biomass production of drained plants. Biomass of waterlogged and flooded M. aquatica was reduced to 57% and 37% in drained conditions. Waterlogged and flooded E. hirsutum had swollen stem bases and invested a high proportion of biomass in adventitious roots. Stems of M. aquatica did not swell, formed few adventitious roots and maintained an equal proportion of below-ground roots at all water levels. The effect of water level on vegetative reproduction corresponded well with the lower hydrological boundaries of both species. When waterlogged and flooded, most rhizomes of E. hirsutum emerged from above-ground parts of the stem base and were oriented in an upward direction. Plants in flooded soil allocated less biomass to rhizomes and also reduced the number and size of rhizomes. Rhizome formation of M. aquatica on the other hand was not directly affected by water level and only depended on plant size. These differences in vegetative reproduction are discussed in relation to the different abilities of both species to oxygenate their below-ground roots. It was concluded that the mode of adaptation to soil flooding might also affect vegetative reproduction and, therefore, a species' ability for long-term persistence in soil-flooded habitats.

Control of sediment dynamics by vegetation as a key function driving biogeomorphic succession within fluvial corridors

“…Whereas the control of sediment dynamics by wetland plants has been identifi ed as an important component of intertidal ecosystem function (Lee and Partridge, 1983;Pasternack and Brush, 1998;Bos et al, 2007;van Hulzen et al, 2007), the effect of riparian vegetation on sediment erosion and deposition within fl uvial systems has been studied mainly from the geomorphic perspective of landform dynamics (Nanson and Beach, 1977;Gurnell et al, 2001;Steiger et al, 2001a;Cotton et al, 2006;Heppell et al, 2009) Riparian habitat structure, water fl ow variability and sediment deposition and erosion were generally considered as limiting factors and as disturbance in the ecological literature (Franz and Bazzaz, 1977;Naiman and Décamps, 1997;Edwards et al, 1999;Lenssen et al, 2000;Amoros and Bornette, 2002). Some geomorphologists have started recently to focus their attention on feedback between form and function in fl uvial ecosystems considering that geomorphology controls riparian vegetation dynamics, and riparian vegetation controls geomorphology (Bendix and Hupp, 2000;Hupp and Bornette, 2003;Gurnell et al, 2000Gurnell et al, , 2005Parsons and Thoms, 2007;Francis et al, in press).…”

Effect of waterlogging on regeneration in the dwarf birch (Betula nana)

“…Waterlogging has been reported to reduce growth in other wetland herbaceous and woody species as well (Squires & van der Valk 1992;Kozlowski 1997;Lenssen et al 2000). The reduction in vegetative growth is primarily due to reduced oxygen availability, which causes the build-up of organic acids and alcohols in the plant cells.…”

“…Vegetative reproduction in flooded habitats may be limited to those areas where the water table is lowest (Squires & van der Valk 1992;Lenssen et al 2000).…”

“…It can also cause premature senescence and death, thereby affecting the species composition of plant communities in wetland habitats (Gunarsson & Rydin 1998;Kozlowski 1997;Lenssen et al 2000Lenssen et al , 2003.…”

Changes in vegetation and soil seed bank of meadow after waterlogging caused by Castor fiber

“…Given the most common effects of anthropogenic transformation of wet habitats, a substantial number of publications are focused on the impact of desiccation on changes occurring at the level of vegetation, population, and soil seed bank [2][3][4][5]. Seasonal floods and prolonged waterlogging caused by stagnation of water in the catchment area are equally important factors exerting a considerable effect on species dynamics and vegetation of hydrogenic areas [6][7][8][9].…”