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Benthic chironomids were present in all communities and other invertebrates (including Gastropods, Nematoda, Odonata, Hemiptera, Culicidae, Ephemeroptera, and Coleoptera), were present in the bulrush, open water and alkali bulrush but not in the backwater and river benthos (Figure 21). Chironomid densities were greatest in the open water community. The bulrush community had the highest densities of other invertebrates. Data presented in Figure 21 shows the importance of chironomids to the river and backwater community invertebrate biomass. Densities of chironomids in the two riverine communities are exceeded only by the open water community. Mean water column and benthic invertebrate densities for all sample dates for each community station are presented in Figure 22. Open water station E2 had the highest densities of water column invertebrates for all stations with a mean of 176 L-1. This station was sampled on all six sample periods. Station E2 in the alkali bulrush community also had high water column invertebrate densities with 119 L'1 but was sampled only on the first three sample periods, as it dried up on 4 August. Bulrush station seasonal means ranged between 5 and 62 organisms L-1. Water column invertebrates at backwater station E6 averaged 0.5 organisms L'1 for the last five sample periods and river station densities for the three stations ranged between 0.008 and 0.09 organisms L'1 for the six sample periods. Benthic invertebrates had the highest densities at station E2 in the alkali bulrush community with 131 organisms L'1. This station dried up on 4 August. Station E1 in the bulrush community was sampled during the first three sample period and had a mean of 114 organisms L'1. No benthic invertebrates were found at bulrush station E2 which was sampled only on the first sample date. Ranges for open water stations were between 46 and 89 organisms L'1. Backwater station E6 averaged 17 organisms L'1. The three river stations ranged between 3 and 37 benthic organisms L'1 over six sample periods. Variability of invertebrate densities between stations within and between community types is evident in the data presented. Differences between palustrine wetland communities (bulrush, open water and alkali bulrush) and riverine communities (backwater and river) are pronounced, especially with respect to water column invertebrates. In general, backwater and river communities are dependent on chironomid larvae for invertebrate biomass production and inland wetlands are more diverse in both water column and benthic invertebrates. 39