Recovery of a cultivation grazer: A mechanism for compensatory growth of <i>Thalassia testudinum</i> in a Caribbean seagrass meadow grazed by green turtles

Abstract Recovery of green turtles ( Chelonia mydas ), mega‐herbivores that consume seagrasses, is resulting in dramatic ecosystem‐wide changes as meadows are returned to a natural grazed state. The turtle grazing strategy, with long‐term cultivation and high foraging site fidelity, distinct from other terrestrial aquatic may affect seagrass compensatory growth responses. Identifying the mechanisms responses essential understand functioning plant systems under regimes. In naturally Caribbean ecosystem, we identify mechanism for by evaluating relationships between Thalassia testudinum morphology growth, intensity, canopy light dynamics ungrazed areas. morphological characteristics explain variability T . differed areas, T. leaf linear area productivity:biomass (P:B) significantly increased above‐ground biomass decreased; P:B also shoot density. Mass areas exhibited an increasing trend density was maintained above threshold 2.5 g dry mass m −2 biomass. trends were opposite those intensity while decreased index (LAI) not affected. Light availability at height greater than attenuation Synthesis Grazing removes biomass, which increases stimulates turnover (i.e. growth). Shoot maintaining LAI harvesting potential. This maximizes potential photosynthetic activity provides capacity sustain support response grazing. study presents novel insight assessing underlying proposes thresholds be used evaluate sustainability situ pressure recovering mega‐herbivore.