Seagrass seeds: ecology, dispersal, and early life stages

Seagrass seeds: ecology, dispersal, and early life stages

“Seagrass ecosystems are shaped by tightly coupled biological and physical processes that determine their persistence, recovery, and response to environmental change”.

This Research Theme examines recruitment processes that control seagrass recovery, from seed production and dispersal to settlement and early seedling survival. It identifies how biological traits and hydrodynamic forcing interact to filter recruitment success across coastal systems.

Sexual reproduction through seeds is a critical, yet often underappreciated, component of seagrass ecology. While adult meadows structure coastal ecosystems through clonal growth and canopy-mediated feedbacks, processes acting on seeds and very early life stages often determine recovery after disturbance, large-scale distribution patterns, and long-term resilience.

This work examines on how biological traits, hydrodynamic forcing, and sediment dynamics interact to determine seed fate, with particular emphasis on Zostera marina and other temperate seagrass species. By integrating field observations, controlled experiments, and applied restoration studies, it identifies why recruitment frequently fails even when adult habitat appears suitable.

This Research Theme provides the recruitment-ecology foundation of the research programme, linking seed production, dispersal, settlement, and early survival to hydrodynamic constraints and restoration success across coastal systems.

Core findings

Seagrass recruitment is governed by a sequence of ecological filters, with hydrodynamic forcing acting as a dominant constraint at multiple stages. My research, conducted in collaboration with colleagues and students, shows that from seed production and dispersal to settlement, burial, and early seedling survival, only a small fraction of seeds successfully pass through the recruitment window. Waves, currents, and sediment dynamics strongly influence whether seeds are retained, buried, predated, or lost, thereby controlling recovery potential at ecosystem scales.

By identifying these recruitment filters and their physical and biological drivers, this work supports predictive assessments of natural recovery and the design of seed- and seedling-based restoration strategies aligned with ecosystem constraints.

Core questions in seagrass seed ecology

This research addresses fundamental questions that underpin both natural recovery and restoration success:

  • When and where are viable seagrass seeds produced?
  • How are seeds transported, retained, or lost by waves and currents?
  • What controls seed burial, sediment oxygen conditions, and persistence?
  • How important is seed predation in limiting recruitment?
  • Which environmental conditions promote germination and early seedling survival?
  • How can seed ecology be used to improve restoration success?

Answering these questions requires explicit integration of biology, hydrodynamics, and sediment processes, rather than treating recruitment as a purely biological phenomenon.

Seed development, germination, and early establishment

Recruitment begins with flowering and seed development, but successful establishment depends on whether viable seeds are produced, when they become available, and how quickly they can transition into seedlings under local conditions. In temperate systems, phenology and developmental stage determine the timing of viable seed supply, while germination and early seedling development define a narrow window for establishment. Conditions that promote germination do not necessarily maximise early survival, and early establishment can fail even when adult habitat appears suitable.

This work links seed development and viability to germination cues and early performance, highlighting practical implications for seed handling and the timing of harvesting, storage, and deployment.

Key publications:

Dispersal and hydrodynamic transport

Once released, seeds interact immediately with hydrodynamic forcing. Waves and currents can disperse seeds over short or long distances, but they can also remove seeds rapidly from suitable habitat if retention mechanisms are weak. Dispersal therefore acts not only as a spreading process, but also as an ecological filter that shapes recruitment patterns and recovery trajectories. This work demonstrates how hydrodynamics and seabed properties jointly control seed transport, trapping, and loss.

Key publications:

Related resources:

Seed fate after settlement: burial, predation, and persistence

After settlement, recruitment depends on sediment stability, burial depth, redox conditions, and predation pressure. Hydrodynamic forcing shapes these processes indirectly by modifying sediment mobility and seabed conditions, while biological interactions can reinforce degraded, unvegetated states. In some systems, strong seed predation or sediment instability prevents recovery even when seed supply and water quality appear favourable. The studies below highlight how physical processes and biological interactions control seed persistence in the seabed and can prevent natural recovery.

Key publications:

From seed ecology to restoration

A major motivation behind this work has been to translate recruitment ecology into practical restoration tools. Seed- and seedling-based restoration can enable larger-scale recovery with reduced donor impacts, but success depends on aligning methods with recruitment constraints, including viable seed supply, retention within suitable habitat, post-settlement survival, and early seedling stability under local hydrodynamic forcing.

This section highlights applied restoration studies that directly use seeds or seedlings, and illustrates how recruitment ecology informs method choice and intervention design.

Key publications:

Applied resources:

For integrated outcomes and site-specific interventions, see the Seagrass restoration Theme

Why seed ecology matters?

Recruitment failure often explains why degraded seagrass meadows do not recover, even after improvements in water quality or reductions in disturbance. By identifying the mechanisms controlling seed fate from development to early establishment, this work provides a foundation for understanding resilience under climate change, eutrophication, and increasing physical disturbance. It also supports restoration strategies that work with, rather than against, the ecological and physical constraints acting on early life stages.

People, collaboration, and use

This research has been conducted in close collaboration with PhD students, postdoctoral researchers, technicians, and international partners, with a strong emphasis on training in field experimentation, seed handling, and process-based ecological thinking.

→ Link to Seagrass Ecology Lab

→ Link to People

How to use this Theme

  • Researchers: Explore recruitment processes and cross-scale ecological filters.
  • Practitioners: Identify constraints and opportunities for seed-based restoration.
  • Students: Use this page as a structured overview of early life-stage processes in seagrasses.

Linked publications, guidelines, and blog posts provide direct access to detailed methods, figures, and data.

Further reading