Rapid plant trait evolution can alter coastal wetland resilience to sea level rise

Abstract

Rapid evolution remains a largely unrecognized factor in models that forecast the fate of ecosystems under scenarios of global change. In this work, we quantified the roles of heritable variation in plant traits and of trait evolution in explaining variability in forecasts of the state of coastal wetland ecosystems. A common garden study of genotypes of the dominant sedge Schoenoplectus americanus , “resurrected” from time-stratified seed banks, revealed that heritable variation and evolution explained key ecosystem attributes such as the allocation and distribution of belowground biomass. Incorporating heritable trait variation and evolution into an ecosystem model altered predictions of carbon accumulation and soil surface accretion (a determinant of marsh resilience to sea level rise), demonstrating the importance of accounting for evolutionary processes when forecasting ecosystem dynamics.

Rapid adaptation of recombining populations on tunable fitness landscapes

“…Another example of rapid polygenic adaptation comes from plant traits of sedge ( Schoenoplectus americanus ) that rapidly responded to sea level rise within 50 years, and the corresponding genotypes are heritable (Vahsen et al 2023). In our study, direct selection with selection coefficient a = 0.01 per allele could fix a set of standing genetic variants within 1000 generations regardless of population size (Figure 3 and S3).…”

Complex eco‐evolutionary responses of a foundational coastal marsh plant to global change

“…2a; Supporting Information Table S1). Although these sites are regionally proximate, our previous analyses of genetic variation measured according to microsatellite loci (Summers et al, 2018) and genomic variation measured according to SNP loci (Vahsen et al, 2023) suggest that there is considerable differentiation between S. americanus populations at these (and New Phytologist other nearby) sites. Seeds were wet-sieved and germinated in Conviron growth chambers (Vahsen et al, 2021) and then maintained in pots containing a mixture of sand and potting soil (Fig.…”

“…4a, left). Predicting how plant traits will shift due to the evolution of plasticity under future scenarios of accelerated sea-level rise and increased atmospheric CO 2 has direct consequences on estimates of vertical accretion and carbon sequestration rates in coastal marshes, as these processes are sensitive to traits such as aboveground biomass and root-to-shoot ratio (Vahsen et al, 2023). For example, the stimulation effect of CO 2 on plant traits in ecosystem models such as Rietl et al (2021) that predict accretion and carbon accumulation may be contingent on salinity and evolutionary factors.…”

“…evolution on ‘ecologically relevant’ timescales) can be an important driver of ecosystem change (e.g. Hairston et al ., 2005; Franks et al ., 2014; Geerts et al ., 2015; Valencia‐Montoya et al ., 2021; Mozdzer et al ., 2022; Vahsen et al ., 2023).…”

Reproductive responses to increased density and global change drivers in a widespread clonal wetland species, Schoenoplectus americanus

“…and Smith 2002), is a dominant species in Chesapeake Bay wetlands(McCormick and Somes 1982) and will be an important species in coastal wetlands as they respond to changing climatic conditions(Noyce et al 2023;Vahsen et al 2023). It will be an especially important species in in uencing wetland response to sea level rise at is has been shown to be most abundant and productive when tidal ooding is frequent(Kirwan and Guntenspergen 2015; Holmquist et al 2021).…”