within the sediment. Urchins then moved within the sediment for an average distance of 29.3 cm (± 0.3, range: 23 35 cm cm within a day. – day−1, ~1.2 hr−1) Measurements of sand dollar movement in laboratory conditions and suggest in situ, individual sand dollars could disturb ~0.15 - 0.4 m2 day 1 respectively, and their populations − could disturb between 6-16 m2 of the survey area and 3-8 seeds, or 13-35% of all recorded seeds, daily at the densities recorded at OAC. Individual sea stars moving across the sediment could disturb ~1.35 m2 day 1 and the sea star population at OAC could disturb ~75 m2 and – ~38 seeds, 100% of recorded seeds, per day. Last, heart urchins observed in Shark Bay could disturb ~0.4 m2 per day at their highest densities recorded in this study, however, at higher observed densities of 2-4 urchins (J. Statton, urchins could personal communication), m−2 disturb ~3 m2 per day. If 50 m2 restoration plots at OAC in Cockburn Sound or UL1 in Shark Bay were broadcast with 100 seeds m-2, sand dollars could disturb 600 1600 seeds daily – of the seeds in the 50m2 plot), sea stars could disturb 7500 seeds daily (100% of the seeds in the 50 m2 plot), and heart urchins could disturb 40-300 seeds daily (0.8 6% of the seeds in – the 50 m2 plot). Field Bioturbator Experiments Recently Settled Seed – The three species of bioturbators exhibited different movement characteristics, affecting how they disturbed seeds on the surface versus seeds buried within the sediment. All three species of sediment bioturbators examined were capable of dislodging recently settled seeds in both Cockburn Sound and Shark Bay. The odds of a seed being disturbed were significantly higher in lanes with fauna present; sand dollars (odds ratio: 50.4, 95% CI: 8.8-290, p < 0.001),
within the sediment. Urchins then moved within the sediment for an average distance of 29.3 cm (± 0.3, range: 23 – 35 cm day−1, ~1.2 cm hr−1) within a day. Measurements of sand dollar movement in laboratory conditions and in situ, suggest individual sand dollars could disturb ~0.15 - 0.4 m2 day − 1 respectively, and their populations could disturb between 6-16 m2 of the survey area and 3-8 seeds, or 13-35% of all recorded seeds, daily at the densities recorded at OAC. Individual sea stars moving across the sediment could disturb ~1.35 m2 day – 1 and the sea star population at OAC could disturb ~75 m2 and ~38 seeds, 100% of recorded seeds, per day. Last, heart urchins observed in Shark Bay could disturb ~0.4 m2 per day at their highest densities recorded in this study, however, at higher observed densities of 2-4 urchins m−2 (J. Statton, personal communication), urchins could disturb ~3 m2 per day. If 50 m2 restoration plots at OAC in Cockburn Sound or UL1 in Shark Bay were broadcast with 100 seeds m-2, sand dollars could disturb 600 – 1600 seeds daily of the seeds in the 50m2 plot), sea stars could disturb 7500 seeds daily (100% of the seeds in the 50 m2 plot), and heart urchins could disturb 40-300 seeds daily (0.8 – 6% of the seeds in the 50 m2 plot). Field Bioturbator Experiments – Recently Settled Seed The three species of bioturbators exhibited different movement characteristics, affecting how they disturbed seeds on the surface versus seeds buried within the sediment. All three species of sediment bioturbators examined were capable of dislodging recently settled seeds in both Cockburn Sound and Shark Bay. The odds of a seed being disturbed were significantly higher in lanes with fauna present; sand dollars (odds ratio: 50.4, 95% CI: 8.8-290, p < 0.001),
AAM_a_sediment.docx