Green grass and high tides: grazing lawns in terrestrial and aquatic ecosystems (commentary on Burkepile 2012)

Deron Burkepile advances a review of compelling empirical examples arguing that common mechanisms may structure grazing systems in both terrestrial and aquatic biomes. We welcome this synthesis, and on many specific points we concur. In this commentary we further develop the characteristics of grazing systems, grazing lawns in particular, reviewing their prevalence across systems wet and dry. Then, we use studies from terrestrial browsing systems – and their aquatic parallels – to explore major contrasts that are still prominent in cross-system comparisons. We rely heavily on quantitative reviews and meta-analyses to assess the prevalence and generality of the evidence for common mechanisms across grazing ecosystems. Although this approach sacrifices the detail from singular studies, it avoids undue focus on singular exceptions, instead highlighting key similarities and contrasts across biomes.