A comparison of selected ecosystem attributes of three South African estuaries with different freshwater inflow regimes, using network analysis

摘要: Carbon flow networks of the Kromme, Swartkops and Sundays estuaries, situated on south coast South Africa, were analysed using ecological network analysis. A major difference between three estuaries is freshwater inflow regimes: The Kromme Estuary receives very little (annual mean 0.07 m 3 s 1 ), annually about 0.82 while average 2.74 annually. Ecological analysis revealed differences most ecosystem attributes such as cycling carbon, trophic structure, organisational developmental status in terms ascendency redundancy, regarding contribution to dependencies compartments one another network. Due lack frequent consequently renewal nutrient pool, recycles its material showed highest detritivory/herbivory ratio (57:1), whereas least proportion had lowest at 10:1. Estuary, hitherto believed be dominated by pelagic production, was found rely more benthic biota carbon throughput inferred from dependency coefficients, than communities. low rate fresh water into absence an axial salinity gradient, a comparatively high Finn Cycling Index 40%, long exchange time, this system appears have developed barmQ sea. System level properties A/C ratio, Average Mutual Information index, food web connectance increase values calculated for intermediate FCI followed inverse trend systems. D 2005 Elsevier B.V. All rights reserved.