Responsiveness of performance and morphological traits to experimental submergence predicts field distribution pattern of wetland plants

Abstract

Question: Plant trait mean values and trait responsiveness to different environmental regimes are both important determinants of plant field distribution, but the degree to which plant trait means vs trait responsiveness predict plant distribution has rarely been compared quantitatively. Because hydrological regime is a key determinant of wetland plant distribution, we hypothesized that both plant trait means and trait responsiveness to experimental submergence could predict plant adaptation to a wet or a dry part of hydrological gradients in wetlands.Location: Beijing, China. Methods:We measured mean values for 14 plant traits by growing 30 wetland species both on land (control) and partially submerged in a greenhouse, and calculated log response ratios (LnRRs) of these traits to submergence. A distribution pattern index of wetland plants along the moisture gradient (from the zone furthest from the wetland waterline to that nearest to the waterline) was developed based on plant survey data in 3988 field plots in 24 wetlands in Beijing, China.Results: LnRRs of performance traits (shoot biomass, root biomass, plant height and total root length; R 2 = 0.249, P = 0.005) and one out of five morphological traits (i.e. shoot elongation capacity; R 2 = 0.194, P = 0.015) between partially submerged and control treatments could predict the distribution pattern of the 30 wetland plant species. In contrast, means of plant traits in either control or submergence could not predict species distribution. The trait LnRRs, increasing from very negative to very positive, corresponded positively with the distribution, ranging from the zone furthest from the wetland waterline to that nearest to the waterline. Surprisingly, physiological trait LnRRs that had been expected to underpin performance trait LnRRs did not themselves predict the distribution pattern of these species. Analyses at the level of multivariate trait groups (based on PCA) showed that species LnRRs of the morphological trait group were positively correlated with LnRRs of the performance trait group.Conclusions: Our findings demonstrate that screening wetland plant species for performance and morphological trait LnRRs under experimentally flooded conditions is an effective approach to understand and predict their distribution pattern along moisture gradients in the field.

Testing mechanisms underlying responses of plant functional traits to flooding duration gradient in a lakeshore meadow

“…In response to flooding stress, species could adopt the escape strategy and grow faster to retain or develop structures that facilitate gas exchange between the plants and their submerged environment (Colmer and Voesenek 2009). These species would, therefore, have greater height, individual biomass, specific leaf area (Mommer et al 2006;Panda et al 2008;Fu et al 2015, Garssen et al 2015Luo et al 2016) (Table 1). In contrast, some species adopt the quiescence strategy, in which all plant materials remain submerged underwater, while their traits show much smaller responses to flooding than those adopting an escape strategy (Colmer and Voesenek 2009;Shi et al 2015) (Table 1).…”

Drivers of plant traits that allow survival in wetlands

“…Wetland adaptive traits are the premise of survival under the adverse conditions present in wetlands (Moor et al, ; Pan et al, ; Voesenek & Bailey‐Serres, ). The identified environmental filters in wetlands select plants with suitable adaptive traits, along with other factors including soil fertility, light radiation, competition/facilitation in communities (Luo et al, ). Disentangling the driving factors for wetland adaptive traits not only provides a theoretical basis for understanding the overall wetland plant functioning and strategy, but also creates new perspectives on modelling global wetland plant distributions and community structure (Lenssen, Menting, Van der Putten, & Blom, ; Visser, Bögemann, Van De Steeg, Pierik, & Blom, ; Willby, Pulford, & Flowers, ).…”

Local flooding history affects plant recruitment in riparian zones

“…In order to replace the mal‐adapted species, the better‐adapted species will have to arrive, germinate and establish under the new conditions, and these processes take time. Separate studies have confirmed the link between flow regime and dispersal (Bourgeois, Gonzalez, Vanasse, Aubin, & Poulin, ; Fraaije et al., ; Soomers et al., ) and with habitat characteristics important for germination and establishment, such as soil moisture (Kotowski, Beauchard, Opdekamp, Meire, & van Diggelen, ; Luo et al., ; Sarneel, Janssen, Rip, Bender, & Bakker, ) or sedimentation (Levine & Stromberg, ). Since germination and early establishment are hard to separate under field conditions, they are collectively referred to as recruitment in this study.…”