Soft -Bottom Fauna of a Tropical and a Temperate Intertidal Area
261
12.3.2 Faunal Inventories
The inventory of the Bane d' Arguin tidal flats in September 1988 comprises a
total of 132 taxa from only 30 sampling stations (Table 12.1). The complete
taxonomical and autecological results will be given in a separate publication.
The main species groups are (number of species in brackets): Polychaeta (57),
Crustacea (32), Mollusca (25), Sipunculida (7), Oligochaeta (3), Echinodermata (3), Porifera (1),Cnidaria (1), Tunicata (1),Acrania (1) and Hexapoda (1).
From 104 sampling stations in the Iuist area 78 species were obtained
(Obert and Michaelis, in prep.). The main groups are (species numbers in
brackets): Polychaeta (30), Crustacea (20), Mollusca (15), Oligo chaeta (5),
Hexapoda (3), Coelenterata (2), Nemertini (1), Bryozoa (1) and Echinodermata (1). On the tropical Bane d'Arguin as well as in the temperate Iuist area
polychaetes, crustaceans and molluscs dominate by species number.
12.3.3 Structure and Distribution of Macrozoobenthos Assemblages
Tables 12.2 and 12.3 present mean species numbers, total abundance and total
biomass of the individual habitats and of the entire investigated areas on the
Bane d' Arguin and in the Wadden Sea. The values for the entire areas were
calculated without considering the supralittoral sebkha on the Bane d' Arguin
and the supralittoral high sands in the Iuist area. On the Bane d' Arguin
(Table 12.2) the means of all eulittoral stations amount to 16 species per
station, slightly over 2000 individuals m- 2 and a biomass of 7.6 g ADW m- 2 • In
the latter value the biomass of the large bivalve Anadara senilis is not included
following the example of the preceding surveys (Altenburg et al. 1982; Wolff
1991; Wolff et al. 1993a). In September 1988 the mean share amounted to l.7 g
ADW m- 2 which leads to a total biomass of 9.3 g ADW m- 2 •
In the Iuist area (Table 12.3) the resulting mean values from all stations
(excluding the mussel beds and the high sands) are 10 species per station,
4180 individuals m- 2 and 32.7 g ADW m- 2 • With the mussel beds included, the
mean total biomass amounts to 4l.2 g ADW m- 2 •
In the following short descriptions the habitats are arranged from seaward
low intertidal through landward high intertidal to supralittoral (see also
Tables 12.2 and 12.3 and Figs. 12.4-12.8).
Banc d'Arguin - Exposed Beaches (Table 12.2). The spectrum of 33 species
comprises rare species limited to this habitat like the polychaetes Hyboscolex
longiseta and Scolelepis squamata. Three species dominate, viz. Apseudidae
sp. 1 and S. squamata, dominant in both number and weight, and juvenile Uca
tangeri, providing the highest share of biomass.
261
12.3.2 Faunal Inventories
The inventory of the Bane d' Arguin tidal flats in September 1988 comprises a
total of 132 taxa from only 30 sampling stations (Table 12.1). The complete
taxonomical and autecological results will be given in a separate publication.
The main species groups are (number of species in brackets): Polychaeta (57),
Crustacea (32), Mollusca (25), Sipunculida (7), Oligochaeta (3), Echinodermata (3), Porifera (1),Cnidaria (1), Tunicata (1),Acrania (1) and Hexapoda (1).
From 104 sampling stations in the Iuist area 78 species were obtained
(Obert and Michaelis, in prep.). The main groups are (species numbers in
brackets): Polychaeta (30), Crustacea (20), Mollusca (15), Oligo chaeta (5),
Hexapoda (3), Coelenterata (2), Nemertini (1), Bryozoa (1) and Echinodermata (1). On the tropical Bane d'Arguin as well as in the temperate Iuist area
polychaetes, crustaceans and molluscs dominate by species number.
12.3.3 Structure and Distribution of Macrozoobenthos Assemblages
Tables 12.2 and 12.3 present mean species numbers, total abundance and total
biomass of the individual habitats and of the entire investigated areas on the
Bane d' Arguin and in the Wadden Sea. The values for the entire areas were
calculated without considering the supralittoral sebkha on the Bane d' Arguin
and the supralittoral high sands in the Iuist area. On the Bane d' Arguin
(Table 12.2) the means of all eulittoral stations amount to 16 species per
station, slightly over 2000 individuals m- 2 and a biomass of 7.6 g ADW m- 2 • In
the latter value the biomass of the large bivalve Anadara senilis is not included
following the example of the preceding surveys (Altenburg et al. 1982; Wolff
1991; Wolff et al. 1993a). In September 1988 the mean share amounted to l.7 g
ADW m- 2 which leads to a total biomass of 9.3 g ADW m- 2 •
In the Iuist area (Table 12.3) the resulting mean values from all stations
(excluding the mussel beds and the high sands) are 10 species per station,
4180 individuals m- 2 and 32.7 g ADW m- 2 • With the mussel beds included, the
mean total biomass amounts to 4l.2 g ADW m- 2 •
In the following short descriptions the habitats are arranged from seaward
low intertidal through landward high intertidal to supralittoral (see also
Tables 12.2 and 12.3 and Figs. 12.4-12.8).
Banc d'Arguin - Exposed Beaches (Table 12.2). The spectrum of 33 species
comprises rare species limited to this habitat like the polychaetes Hyboscolex
longiseta and Scolelepis squamata. Three species dominate, viz. Apseudidae
sp. 1 and S. squamata, dominant in both number and weight, and juvenile Uca
tangeri, providing the highest share of biomass.