Facultative Annual Life Cycles in Seagrasses

Area of Science:

• Marine Botany
• Plant Ecology
• Life History Evolution

Background:

• Plant life cycles are typically annual or perennial.
• Facultative annual species exhibit environmental flexibility, adopting either life cycle.
• While rare in terrestrial plants, this trait is more prevalent in marine angiosperms (seagrasses).

Purpose of the Study:

• To review the prevalence and characteristics of facultative annual species in seagrasses.
• To investigate the environmental factors influencing life cycle shifts in seagrasses.
• To explore the reproductive and evolutionary implications of flexible life histories in marine plants.

Main Methods:

• Literature review of seagrass life cycles and environmental influences.
• Analysis of published data on facultative annual seagrass species.
• Case study of an estuarine seagrass population's life cycle shift over five years.

Main Results:

• Six out of 63 seagrass species are facultative annual, found globally.
• Annual seagrass populations yield approximately five times more seeds than perennial ones.
• Environmental stressors like desiccation, anoxia, shading, and heat induce annual life cycles.

Conclusions:

• Facultative annual life cycles are a common and adaptive strategy in seagrasses.
• Environmental conditions significantly influence seagrass life cycle plasticity.
• Understanding these flexible life histories offers insights into plant reproduction and senescence.