168
E. Flach and A. Tamaki
and De VIas 1979). However, during a period of eutrophication, resulting in a
higher food supply to the benthos (Beukema and Cadee 1986), the overall
numbers and biomass of the lugworm in the Wadden Sea increased (Beukema
1991,1992).
In Tomioka Bay, intraspecific competition for space seems to regulate the
adult ghost shrimp population at the carrying capacity during the stable
phase (Tamaki and Veno 1998). The adult-juvenile interaction, however,
appears to be positive, at least for juvenile ghost shrimps. The presence of
adult ghost shrimps facilitates the larval settlement, just because of their bioturbating activities, which makes the sediment more easily penetrated by the
larvae (Tamaki and Ingole 1993). This positive adult-juvenile interaction is
one of the main differences between the ghost shrimp and the lugworm, and
at least partly responsible for the population expansion of the ghost shrimp in
Ariake Sound. The higher survival rate of the pelagic larvae, however, seems
to be the result of a change in the physical environment.
It can thus be concluded that the physical environment is important in
setting the boundaries for the populations of key-species, such as the large
bioturbating ghost shrimp and lugworm, on a large scale. On a smaller scale,
intraspecific interactions are important in regulating densities and distribution patterns of these key-species. Besides intraspecific interactions within
the key-species, interspecific interactions, either positively or negatively
related to the populations of the key-species, have a strong impact on the
whole benthic community on intertidal sand flats all over the world.
References
Aller RC, Dodge RE (1974) Animal-sediment relations in a tropical lagoon Discovery
Bay, Jamaica. J Mar Res 32:209-232
Aller RC, Yingst JY (1985) Effects of marine deposit-feeders Heteromastus fiiiformis
(Polychaeta), Macoma balthica (Bivalvia), and Tellina texana (Bivalvia) on averaged
sedimentary solute transport, reaction rates, and microbial distribution. J Mar Res
43:615-645
Andersen F0, Kristensen E (1991) Effects of burrowing macrofauna on organic matter
decomposition in coastal marine sediments. Symp Zool Soc Lond 63:69-88
Arthur W, Mitchell P (1989) A revised scheme for the classification of population
interactions. Oikos 56: 141-143
Berry AJ (1986) Daily, tidal and two-weekly spawning periodicity and brief pelagic
dispersal in the tropical intertidal gastropod Umbonium vestiarium (L.). J Exp Mar
Bioi EcoI95:211-223
Beukema JJ (1976) Biomass and species richness of the macrobenthic animals living on
tidal flats in the western part of the Wadden Sea. Mar Bioi 99:425-433
Beukema JJ (1991) Changes in composition of bottom fauna of a tidal-flat area during a
period of eutrophication. Mar Bioi 111:293-301
E. Flach and A. Tamaki
and De VIas 1979). However, during a period of eutrophication, resulting in a
higher food supply to the benthos (Beukema and Cadee 1986), the overall
numbers and biomass of the lugworm in the Wadden Sea increased (Beukema
1991,1992).
In Tomioka Bay, intraspecific competition for space seems to regulate the
adult ghost shrimp population at the carrying capacity during the stable
phase (Tamaki and Veno 1998). The adult-juvenile interaction, however,
appears to be positive, at least for juvenile ghost shrimps. The presence of
adult ghost shrimps facilitates the larval settlement, just because of their bioturbating activities, which makes the sediment more easily penetrated by the
larvae (Tamaki and Ingole 1993). This positive adult-juvenile interaction is
one of the main differences between the ghost shrimp and the lugworm, and
at least partly responsible for the population expansion of the ghost shrimp in
Ariake Sound. The higher survival rate of the pelagic larvae, however, seems
to be the result of a change in the physical environment.
It can thus be concluded that the physical environment is important in
setting the boundaries for the populations of key-species, such as the large
bioturbating ghost shrimp and lugworm, on a large scale. On a smaller scale,
intraspecific interactions are important in regulating densities and distribution patterns of these key-species. Besides intraspecific interactions within
the key-species, interspecific interactions, either positively or negatively
related to the populations of the key-species, have a strong impact on the
whole benthic community on intertidal sand flats all over the world.
References
Aller RC, Dodge RE (1974) Animal-sediment relations in a tropical lagoon Discovery
Bay, Jamaica. J Mar Res 32:209-232
Aller RC, Yingst JY (1985) Effects of marine deposit-feeders Heteromastus fiiiformis
(Polychaeta), Macoma balthica (Bivalvia), and Tellina texana (Bivalvia) on averaged
sedimentary solute transport, reaction rates, and microbial distribution. J Mar Res
43:615-645
Andersen F0, Kristensen E (1991) Effects of burrowing macrofauna on organic matter
decomposition in coastal marine sediments. Symp Zool Soc Lond 63:69-88
Arthur W, Mitchell P (1989) A revised scheme for the classification of population
interactions. Oikos 56: 141-143
Berry AJ (1986) Daily, tidal and two-weekly spawning periodicity and brief pelagic
dispersal in the tropical intertidal gastropod Umbonium vestiarium (L.). J Exp Mar
Bioi EcoI95:211-223
Beukema JJ (1976) Biomass and species richness of the macrobenthic animals living on
tidal flats in the western part of the Wadden Sea. Mar Bioi 99:425-433
Beukema JJ (1991) Changes in composition of bottom fauna of a tidal-flat area during a
period of eutrophication. Mar Bioi 111:293-301