Do Amplitudes of Water Level Fluctuations Affect the Growth and Community Structure of Submerged Macrophytes?

Abstract

Submerged macrophytes are subjected to potential mechanical stresses associated with fluctuating water levels in natural conditions. However, few experimental studies have been conducted to further understand the effects of water level fluctuating amplitude on submerged macrophyte species and their assemblages or communities. We designed a controlled experiment to investigate the responses of three submerged macrophyte species (Hydrilla verticillata, Ceratophyllum demersum and Elodea nuttallii) and their combinations in communities to three amplitudes (static, ± 30 cm, ± 60 cm) of water level fluctuations. Results showed that water level fluctuating amplitude had little effects on the community performance and the three tested species responded differently. H. verticillata exhibited more growth in static water and it was negatively affected by either of the water level fluctuations amplitude, however, growth parameters of H. verticillata in two fluctuating water level treatments (i.e., ± 30 cm, ± 60 cm) were not significantly different. On the other hand, the growth of C. demersum was not significantly correlated with different amplitude treatments. However, it became more abundant when water levels fluctuated. E. nuttallii was inhibited by the two fluctuating water level treatments, and was less in growth parameters compared to the other species especially in water level fluctuating conditions. The inherent differences in the adaptive capabilities of the tested species indicate that C. demersum or other species with similar responses may be dominant species to restore submerged macrophyte communities with great fluctuating water levels. Otherwise, H. verticillata, E. nuttallii or other species with similar responses could be considered for constructing the community in static water conditions.

Phenotypic plasticity of Stratiotes aloides L. (Hydrocharitaceae)

“…Some authors argue that water level fluctuation may poten tially increase the vegetative spread of submerged macro phyte communities and managing water level fluc tua tion may be helpful for the restoration of submerged mac rophyte communities in degraded wetlands (Wang et al 2016). Undoubtedly, water level and the depth of S. aloides plants immersion are of importance for the plants' reproduction.…”

Associations between Macrophyte Life Forms and Environmental and Morphometric Factors in a Large Sub-tropical Floodplain

“…Some variables that were found to be related with the biomass of life forms have previously been related to taxonomic attributes (e.g., Murphy et al, 2003 ; Schneider et al, 2015 ; Wang et al, 2016 ; Riera et al, 2017 ), which suggests that changes in the taxonomic structure can primarily result from the responses of life forms to environmental changes. For example, we found that changes in the biomasses of macrophyte life forms were strongly explained by the degree of connectivity, which was negatively related with three (Em, RS, and FS) out of seven life forms.…”

“…Connected floodplain waterbodies are exposed to frequent water level fluctuations. This situation leads to a high instability of habitats, which may affect macrophyte life forms in different ways (Partanen et al, 2006 ; Neiff et al, 2008 ; Zhang et al, 2015 ; Wang et al, 2016 ). For instance, changes of water depth related to water level fluctuations could be catastrophic for RS (devoid of cuticle and supporting tissues) when exposed to air conditions or to very large floods (Sousa et al, 2010 ).…”

Long Term Aquatic Vegetation Dynamics in Longgan Lake Using Landsat Time Series and Their Responses to Water Level Fluctuation

“…Different macrophyte species of identical life form may also response to WLF differently. By treatment of three submerged macrophytes under different amplitude of WLF, Wang et al [15] found Hydrilla verticillata exhibited more growth in static water, and Elodea nuttallii was inhibited by fluctuating water level treatments, while Ceratophyllum demersum became more abundant when water levels fluctuated.…”