Document Type
Peer-Reviewed Article
Publication Date
2024
Abstract
Species conservation and management benefit from precise understanding of natural patterns of dispersal and genetic variation. Using recent advances in indirect genetic methods applied to both adult plants and dispersed seeds, we find that the mean seed dispersal in a threatened marine foundation plant (the eelgrass Zostera marina) is approximately 100-200 m. This distance is surprisingly more similar to that of wind-dispersed terrestrial seeds (~10s to 100s of meters) than the passive dispersal of marine propagules via currents (~10s to 100s of kilometres). Because nearshore marine plants like Zostera are commonly distributed across strong selective gradients driven by bathymetry (depth) even within these restricted spatial scales, seeds are capable of dispersing to novel water depths and experiencing profound shifts in light availability, temperature and wave exposure. We documented strong phenotypic variation and genome-wide differentiation among plants separated by approximately the spatial scale of mean realised dispersal. This result suggests genetic isolation by environment in response to depth-related environmental gradients as one plausible explanation for this pattern. The ratio of effective to census size (or Ne/Nc) approximated 0.1%, indicating that a fraction of existing plants provides the genetic variation to allow adaptation to environmental change. Our results suggest that successful conservation of seagrass meadows that can adapt to microspatial and temporal variation in environmental conditions will be low without direct and persistent intervention using large numbers of individuals or a targeted selection of genotypes.
Recommended Citation
Sotka, E. E., Hughes, A. R., Hanley, T. C., & Hays, C. G. (2024). Restricted dispersal and phenotypic response to water depth in a foundation seagrass. Molecular Ecology, e17565. Doi: 10.1111/mec.17565
Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial 3.0 License
Comments
Online ahead of print, October 30, 2024
This work was supported by National Science Foundation for funding (OCE-1851262 to E.E.S., OCE-1851043 to A.R.H. and T.C.H., and OCE-1851432 to C.G.H.)
This is an open access article under the terms of the Creative Commons Attribution-NonCommercial License