Size matters: variations in seagrass seed size at local scales affects seed performance

Abstract Seed size can have an impact on angiosperm reproductive fitness. Ecological theory predicts plants that will produce larger seeds in stressful environments to increase the chances of seedling survival and numerous small favourable conditions number recruits. We measured seed morphology seagrass Heterozostera nigricaulis from four populations under differing environmental South East Australia. mass among sites showed consistent differences over flowering seasons. Seeds exposed, ephemeral meadows (Blairgowrie, Edwards Point) were 19%–53% heavier than those larger, stable at more sheltered (Swan Bay, Point Henry). Overall, exposed performed better germination experiments persisted (remained viable) longer compared sites. contrasting levels performance. Small Swan Bay had lowest but proportion viable after 12 months much higher (41%) similar sized Henry (0%). There are clear life history benefits large facilitate persistence sites; however, performance smaller varied between may be a function other site-specific advantages.