Hydro-ecological relations in the Delta Waters
Hydro-ecological relations in the Delta Waters Hydro-ecological relations in the Delta Waters
of birds and this: immediately stresses the internatianal importance M the Delta. Criteria have been agreed upon intsrnatiooally to &press the importance of a wetland area CSzijj, 1972): if more than 1% of a population (either 20 000 waders or 10 000 ducks) r-ularly occurs, the area is considered to be of international importance. In the Delta area the numbers of /+l species exceed these criteria. Figure 4 Proportion of the tetal number of waterbirda in the Delta occurring in each of the basins. (Vmordelta (M); Westerschelde (WS); Oasterschelde (OS) ; Krammer-Volkerak (KV) ; Grevelingen Meer (GM) ; Veerse Meer (W); Haringvliet (HV); Bollands Diep (BD) ; Biesboseh (BB)) The bir& are not evenly spread over the whole Delta area. In Figure 4 the relative importance of each basin is given (expressed ss the percentage the total number of birds in each basin represent$ of the ove~all total number in the Delta). The oatstanding importance of the Ooster- and Westerschelde is very clear. With less than 50% af the total vetland area they accmmodate 67% ef the birds of Khe whole Delta area. KQV this distribution is related to rood supply will be analyzed in the fallowing bections.
. DISTRIBUXIOBI OF WATEJBIRoS OVER TEE DIFFEREMT BASINS RELATIOIIS WITK THE FQOD SUEPLY Before relating the occurrence of birds to the distribution of their food it is necessalry to describe the position of the birds in the estuarine or lake ecosystems. Weretore a simplified model of the energy fXmes in the different basins is giuen in Figure 5. Figure 5 Schwatic represeatation of the majar links in the foed veh in the basins of tke Delta area flurrients are used by phytoplankton, mi~rophytobenthos and macrwalgae. The latwr, together with saltmash plants, their seeds or the ve&etarion along the banks a d adjacent agricultural areas are the main food source for herbivores, being geese and most specles of dabhlwg ducks. Plicropbytohenthos can be usecl as a food source by a faw birds, especially Sbelducks. The mrozoohenthos, large sized I . I mm) inaertekates living in the sediment, can be divided into filterfeeders, depositfeeders, scavensers and predators. Filherfaeders. mainly molluscs such as Cockles (Ceraetoderna edule) an& Wssel.
- Page 76 and 77: less predictable for water managers
- Page 78 and 79: ILWNEWIJK, A.. KEIP, C., 1988. De v
- Page 80 and 81: XBE CHANGING TmAL LAMXiCAPE I N TEE
- Page 82 and 83: The storm surke of L&Z1 A.D., knorm
- Page 84 and 85: osi* rn@8IOIP m .SL 4 Has F~~ULB 3
- Page 86 and 87: During the 19th century man starts
- Page 88 and 89: mudflats have retreated some 100-20
- Page 90 and 91: aq811~33a.e~ pue 3pTatlJS uxaJsafi
- Page 92 and 93: Erosion by waves of sandy shoals (c
- Page 94 and 95: Lt has been estimated that the sedi
- Page 96 and 97: Implementafion of the Delta Project
- Page 98 and 99: ECOLOGICAL DEVELOWdENT OF SALT MAKS
- Page 100 and 101: fn tidal water systems sedimentatio
- Page 102 and 103: hierarchical position. Tn the egtua
- Page 104 and 105: Of course. tke environmental change
- Page 106 and 107: wind erasson, desaliuation, aeratio
- Page 108 and 109: Fonner tirtal flats with saltmarsh
- Page 110 and 111: Grevelingen. Lake Veere and Krammer
- Page 112 and 113: As mentioned above aa important que
- Page 114 and 115: A seaond important perspective for
- Page 116: BEEEXNX, W.D. and 80ZBf&. J. L9M. T
- Page 119 and 120: are determining the dfstrlbution af
- Page 121 and 122: this volume or in Duutsaa, et aL, 1
- Page 123 and 124: artificial waterflow was created af
- Page 125: of waterbirds occur regulsrly. The
- Page 129 and 130: small bird$ extludiag them vill net
- Page 131 and 132: In order to lsok for relatiouehips
- Page 133 and 134: Table 3 Biomass of macroroobenthos
- Page 135 and 136: freshwater basins. Clearly the pres
- Page 137 and 138: scmthem bottueary o-f the winter di
- Page 139 and 140: OCLURRENCE AND DIET QF B ~T .tUQ 80
- Page 141 and 142: 5.2 H- factors Next to all fartors
- Page 143 and 144: Bewick's Swans (Cygnus columbariusl
- Page 145 and 146: m's activiries do not always have t
- Page 147 and 148: measure affecting food supply or av
- Page 149 and 150: DOQiWT$QS, G. 4 TWISK, F., 1987. De
- Page 151 and 152: MEININGEB, P.L. and HAPEREX, A.M.M.
- Page 153 and 154: PISCIVORES Litfle Grebe Great Crest
- Page 156 and 157: IPYBRO-EGOLOOIOAL BELATIONB ZN THE
- Page 158 and 159: apart from upstream purification; -
- Page 160 and 161: Storm surge barrier Eastern Scheldt
- Page 162 and 163: - In addition to existing managemen
- Page 164 and 165: Nature is pliable. Belattvely young
- Page 166 and 167: Ro. 1. No. 2. SQ. 3. Investigations
- Page 168 and 169: 25. The relation between water quan
. DISTRIBUXIOBI OF WATEJBIRoS OVER TEE DIFFEREMT BASINS<br />
RELATIOIIS WITK THE FQOD SUEPLY<br />
Before relat<strong>in</strong>g <strong>the</strong> occurrence of birds to <strong>the</strong> distribution of <strong>the</strong>ir<br />
food it is necessalry to describe <strong>the</strong> position of <strong>the</strong> birds <strong>in</strong> <strong>the</strong><br />
estuar<strong>in</strong>e or lake ecosystems. Weretore a simplified model of <strong>the</strong><br />
energy fXmes <strong>in</strong> <strong>the</strong> different bas<strong>in</strong>s is giuen <strong>in</strong> Figure 5.<br />
Figure 5<br />
Schwatic represeatation of <strong>the</strong> majar l<strong>in</strong>ks <strong>in</strong> <strong>the</strong> foed veh<br />
<strong>in</strong> <strong>the</strong> bas<strong>in</strong>s of tke <strong>Delta</strong> area<br />
flurrients are used by phytoplankton, mi~rophytobenthos and macrwalgae.<br />
The latwr, toge<strong>the</strong>r with saltmash plants, <strong>the</strong>ir seeds or <strong>the</strong><br />
ve&etarion along <strong>the</strong> banks a d adjacent agricultural areas are <strong>the</strong> ma<strong>in</strong><br />
food source for herbivores, be<strong>in</strong>g geese and most specles of dabhlwg<br />
ducks. Plicropbytohenthos can be usecl as a food source by a faw birds,<br />
especially Sbelducks. The mrozoohenthos, large sized I . I mm)<br />
<strong>in</strong>aertekates liv<strong>in</strong>g <strong>in</strong> <strong>the</strong> sediment, can be divided <strong>in</strong>to filterfeeders,<br />
depositfeeders, scavensers and predators. Filherfaeders.<br />
ma<strong>in</strong>ly molluscs such as Cockles (Ceraetoderna edule) an& Wssel.
Change language