The impact of land‐claim on macrobenthos, fish and shorebirds on the forth estuary, eastern Scotland

Abstract 1. The impact of land‐claim on the intertidal areas of the Forth estuary, eastern Scotland is described. It is shown that in recent times almost 50% of the intertidal area has been destroyed for a variety of purposes, including agriculture, harbours and industrial development. 2. The loss of infaunal invertebrate biomass and production from the intertidal habitat has been calculated for each part of the estuary, and by summation for the whole estuary. The loss is discussed in relation to the total biomass and production, both intertidally and subtidally, of the estuary. It is shown that proportionately more biomass and production may have been lost than area. 3. The impact of land‐claim on estuarine fish is calculated. Land‐claim has removed 24% of the natural fish habitats in the Forth estuary, and thereby removed 40% of their food supply. 4. The impact of habitat loss on birds was observed for one area where observations continued throughout a period of land‐claim. For individual bird species at Torry Bay, land‐claim had consequences ranging from neutral to substantially negative. Significant declines were found for overwintering populations of dunlin and bar‐tailed godwit. Comparisons of pre‐ and post‐land‐claim bird feeding usage of this area, showed that the impact of land‐claim on local bird populations differed between species. The large scale loss of habitat on the Forth seems likely to have reduced the size of some shorebird populations which overwinter on the estuary. 5. It is concluded that when considering the impact of land‐claim on estuaries that, as found in some previous studies, a simple consideration of area lost may be inadequate to describe the effects of land‐claim, and the consequences for animals living within the estuary may differ considerably amongst themselves and from area to area.