Table 2 Definitions of the components of primary question b

Native benthic ecosystems

Introduction, establishment and spread of exotic seaweeds

Species/taxa diversity (e.g richness, Simpson/Shannon/Berger-Parker diversity indices), species/taxa evenness (e.g. Pielou evenness index), total community cover, total community biomass, single species/taxa cover, single species/taxa biomass, mortality, density, individual size, individual growth, per capita reproductive output, community productivity, nutrient cycling (e.g. nutrient uptake rate [N, P], nitrification rates), metabolism (e.g. individual/community metabolic rate “B”;[15], oxygen consumption, production of primary or secondary metabolites), decomposition (e.g. abundance of particulate organic carbon [POC] or nitrogen [PON]), carbon flux, respiration, sediment stabilisation (e.g. eroding pulse pressure, sediment mass erosion), sediment mixing (e.g. sediment mixing depth, bioturbation potential “BP”; [16]), resilience (transient differences in spatial/temporal patterns of abundance of single or total species/taxa or composition of assemblages in presence vs absence of the invasive species), temporal (in)stability (e.g. temporal variance in abundance of single species/taxa or total community; temporal (dis)similarity indices), resistance (lack of differences in spatial/temporal patterns of abundance of single or total species/taxa or composition of assemblages in presence vs absence of the invasive species), abundance of epiphytes, richness (i.e. number) of epiphytes, invasibility (presence or abundance of other invasive species)

Invaded unit vs non-invaded unit Unit: organisms/individual/plots/ treatments/areas/sites/locations/regions Invaded unit vs Invader removal unit Unit: organisms/individual/plots/ treatments/areas/sites/locations/regions Control unit (no Invader) vs Invader transplanted unit Unit: organisms/individual/plots/ treatments/areas/sites/locations/regions