More specifically, we expected that
(i) the overall macroinvertebrate density and species
richness would be lower in the presence of crayfish; (ii)
the density and species richness of snails, which are
especially vulnerable to crayfish, would be heavily
reduced by crayfish; (iii) the macroinvertebrate assemblage
composition would be consistently different
between sites with and without crayfish; and (iv) the
responses to crayfish would be different between stony
and vegetated habitats and less pronounced at vegetated
sites due to more complex habitat structure and lower
crayfish density.