Table - Potential effects of human activities on the biological features of intertidal sand and mudflats and subtidal mobile sandbanks

Potential effects of major anthropogenic activities to the biological features of the biotope complexes.

	Biotopes	Benthic community	Fish and shellfish communities	Bird community
Reclamation	Reduction of existing biotope abundance and/or diversity	Reduction of population size and biomass	Reduction of specific prey species and feeding area	Reduction of specific prey species or feeding area
Barrage (amenity and tidal energy)	Predominant biotopes may change	Reduction due to loss of intertidal area Change of feeding types	Reduction of prey species to support fish communities but increase in fish feeding areas	Reduction of prey species and carrying capacity to support bird communities
Dredging activities and aggregate removal	Reduction of existing biotope abundance and/or diversity Change towards biotopes typical of unstable sediment	Reduction in species diversity and abundance due to habitat disruption and smothering	Loss of prey species	Reduction of specific prey species
Fishing activities; shellfish harvesting, bait digging, trawling and potting	May change due to reduction in target benthic species (altered community dynamics) or due to damage to the integrity of habitat	Change to community structure due to loss of target species (bait digging). Also damage to habitat from trawling	Change to community structure due to loss of target species (bait digging) and non-target species. Also damage from trawling. Reduction in specific target species and non target species	Reduction of specific prey species
Organic enrichment	Will change in response to tolerance to anoxia and/or increased nutrients	Decrease in species richness and increase in opportunistic species indicative of organic enrichment, eg. Capitella	Lethal and sublethal effects. Reduction of specific prey species. Loss of resource for harvesting.	Reduction or possible change in specific prey species, change to the palatability of prey
Industrial and domestic discharge	Elimination of vulnerable biotopes to which the toxins are most available	Lethal and sublethal effects. Decrease in species richness and increase in opportunistic species tolerant of pollution	Lethal and sublethal effects including bioaccumulation. Reduction of specific prey species. Loss of resource for harvesting.	Reduction or possible change in specific prey species; possible tainting of prey.
Oil and gas exploration, development and production	Elimination of vulnerable biotopes due to oil spills and/or other discharges. May change due to destruction or smothering of biotopes	Lethal and sublethal effects. Reduction in species diversity and abundance due to habitat disruption and smothering	Noise effect from seismic activity. Lethal and sub lethal effects. Reduction of specific prey species	Reduction or possible change in specific prey species
Recreational disturbance	Trampling of fragile intertidal biotopes	High activity may cause increased pollution	High activity may cause increased pollution	Disturbance to foraging and roosting area and time

Potential effects of major anthropogenic activities to the biological features of the biotope complexes

	Recruitment	Vulnerability to the change in physical environment	Sensitive components
Reclamation	Reduction	Increase due to loss of habitat integrity	All biotopes in area of reclamation and predator species
Barrage (amenity and tidal energy)	Reduction in certain species due to changed hydrophysical regime	Increased instability or changes in environmental parameters due to changed hydrophysical regime	Intertidal biotopes and predator species
Dredging activities and aggregate removal	Benthic spawning area disruption	High risk of smothering or damage/destruction of fauna. Increased instability	Selective elimination of fragile and sedentary infauna and the destruction of the large epifaunal and infaunal organisms eg. Ammodytes
Fishing activities; shellfish harvesting, bait digging, trawling and potting	Benthic spawning area disruption	High risk of smothering or damage/destruction of fauna due to trawling. Increased instability of substratum	Sensitivity of target and non target species to elimination. Habitat destruction due to trawling methods
Organic enrichment	Reduction or possible change in levels of recruitment for some species, effects on metamorphosis		Decrease in organisms that cannot tolerate a low oxygen environment. Sensitivity of certain predator populations that rely on specific prey items.
Industrial and domestic discharge	Sublethal effects on reproduction	Sublethal effects of pollution may have a synergistic effect with other stressors	Decrease in organisms that cannot tolerate the polluted environment. Sensitivity of certain predator populations that rely on specific prey items.
Oil and gas exploration, development and production	Reduction or possible change in levels of recruitment for some species.	High risk of smothering or damage/destruction of fauna. Increased instability	Selective elimination of fragile and sedentary infauna; sensitivity of organisms to oil pollution
Recreational disturbance	Reduction in recruitment/reproduction time	Damage to habitat integrity due to recreational activities such as diving	Increased disturbance effects to sensitive species eg. curlew.