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Advisor(s)
Abstract(s)
Crayfish are major herbivores in freshwaters,
and their activity may change invaded freshwater
ecosystems. Macrophyte removal by crayfish results
from consumption and fragmentation of plant material
and may depend upon the palatability of each species.
We studied the impact of Procambarus clarkii on the
macrophyte community of Mediterranean temporary
ponds, testing in laboratory if consumption and
fragmentation of five macrophyte species were correlated
in palatability tests and in a preference test. We
performed an experiment in a natural pond, where we
introduced crayfish and estimated its effects on
macrophyte biomass, number of rooted stalks and
number of floating cut stalks. P. clarkii consumed
preferably Juncus heterophyllus in both tests and
avoided Carex divisa and Ranunculus peltatus in the
preference test. In the presence of preferred species,
consumption and fragmentation of the non-preferred
species were heavily reduced. In the field trial, the
‘‘Crayfish’’ compartment had 31% less macrophyte
biomass, 41% less rooted stalks and 92% more floating
cut stalks. Crayfish may remove macrophyte species
from the community sequentially, from the most to the
least preferred species. Impacts of crayfish in temporary
ponds may depend on time of invasion and on the
composition of the macrophyte community.
Description
Keywords
Invasive species Freshwater crayfish Herbivory Preference Palatability Mediterranean temporary ponds
Pedagogical Context
Citation
Hydrobiologia, 721, 89-98