Wood Ducks 8 5 



souri, pin oaks (Quercus palustris) within green-tree reservoirs produced an 

 average of 14.2 g/m 2 (McQuilken and Musbach 1977). 



Invertebrates are important waterfowl foods because of their protein 

 and mineral contents, which are essential for egg production in hens and tissue 

 growth of chicks (Krapu 1974, Swanson et al. 1974, Drobney and Fredrickson 

 1979, Drobney 1990). Invertebrate biomass within the impoundments ranged 

 from 0.06 - 0.20 gm/m 2 (Table 2). Insects in the order Odonata (primarily Libel- 

 lulidae) and Heteroptera (primarily Notonectidae) were the most abundant inver- 

 tebrates. Most other groups Were much less abundant (Table 2). 



Table 2. Macroinvertebrate biomass a (in grams) in three blackwater impound- 

 ments at Camp Lejeune in April, May, June, and July 1992. 



Taxa b Pond 



1-1 1-2 1-3 



Chelicerata 



Araneae 0.01 0.05 0.01 



Crustacea 



Amphipoda 0.02 



Decapoda 2.22 1.34 



Insecta 



Coleoptera 



Diptera 



Heteroptera 



Megaloptera 



Odonata 

 Total for all plots 

 Average/ plot 

 Number Plots (15m 2 ) 



a Includes adults, nymphs, pupae, and larvae. 



b For further taxonomic breakdown, see Harper (1993). 



c tr = trace. 



While investigating invertebrate productivity within a blackwater river 

 in south Georgia, Benke et al. (1984) recorded 20-50 times more standing stock 

 biomass on snags than in sandy habitat and 5-10 times more than in muddy habi- 

 tat. They also found increased species richness on snag habitats as compared to 

 other benthic habitats and concluded that production on snags appeared to be 

 limited by available substrate. Thus, blackwater impoundments with significant 



0.27 



0.33 



0.07 



if 



0.09 



ti" 



4.91 



1.34 



0.36 



0.02 



0.45 





2.10 



8.39 



0.07 



7.33 



12.87 



1.85 



2.44 



3.22 



0.93 



3 



4 



2 



