2 figuras, 3 tablasWhile large herbivores can have strong impacts on terrestrial ecosystems, much less is
known of their role in aquatic systems. We reviewed the literature to determine: (1)
which large herbivores (>10 kg) have a (semi-)aquatic lifestyle and are important
consumers of submerged vascular plants, (2) their impact on submerged plant
abundance and species composition and (3) their ecosystem functions.
We grouped herbivores according to diet, habitat selection and movement
ecology: (1) Fully aquatic species, either resident or migratory (manatees, dugongs,
turtles), (2) Semi-aquatic species that live both in water and on land, either resident or
migratory (swans), (3) Resident semi-aquatic species that live in water and forage
mainly on land (hippopotamuses, beavers, capybara), (4) Resident terrestrial species
with relatively large home ranges that frequent aquatic habitats (cervids, water buffalo,
lowland tapir).
Fully aquatic species and swans have the strongest impact on submerged plant
abundance and species composition. They may maintain grazing lawns. Because they
sometimes target belowground parts, their activity can result in local collapse of plant
beds. Semi-aquatic species and turtles serve as important aquatic-terrestrial linkages, by
transporting nutrients across ecosystem boundaries. Hippopotamuses and beavers are
important geomorphological engineers, capable of altering the land and hydrology at
landscape scales. Migratory species and terrestrial species with large home ranges are
potentially important dispersal vectors of plant propagules and nutrients. Clearly, large
aquatic herbivores have strong impacts on associated species and can be critical
ecosystem engineers of aquatic systems, with the ability to modify direct and indirect
functional pathways in ecosystems. While global populations of large aquatic
herbivores are declining, some show remarkable local recoveries with dramatic consequences for the systems they inhabit. A better understanding of these functional
roles will help set priorities for the effective management of large aquatic herbivores
along with the plant habitats they rely on.This research was funded by the
Spanish Ministry of Science and Innovation (CTM2013-48027-C3-3-R), an Intramural
Project from the Spanish National Research Council (CSIC, 201330E062) and the Pew
Marine Fellowship.Peer reviewe