6-28 



Particularly low summer species richness values during the 

 summer have not generally been observed in the NAI study (Table 6-5) . 

 When combined data from both programs are considered, a reoccurring 

 phenomenon of low summer species richness is not apparent (Figure 6-5) . 

 Further discussion of this phenomenon, will be included in the section 

 on faunal densities. 



In addition to the lack of support for a general August effect. 

 Figure 6-5 shows that throughout the study, the mean number of species 

 per station was consistently higher at Morris Cove stations. The gen- 

 eral pattern of fluctuations in species richness was similar for both 

 areas. Morris Cove supported on the order of 1.5 to 2 times as many 

 species per station as the inner harbor. 



Faunal Density 



The mean faunal density for each station/sampling period over 

 the entire study is presented in Table 6-6. The high temporal variation 

 in density observed in New Haven Harbor is similar to other benthic 

 habitats which are unable to support a temporally or spatially persis- 

 tent fauna. The highest densities seen in the data are caused by inva- 

 sions of r-selected opportunistic species that subsequently experience mass 

 mortalities. In turn, other opportunists invade the habitat (McCall, 

 1977; Rhoads, McCall and Yingst, 1978). This colonization pattern is 

 most evident in the inner harbor, which is subjected to greater envi- 

 ronmental stress than Morris Cove. For example. Station 4A experienced 

 a large invasion of Strehlospio benedict! and oligochaetes between 



October and December of 1976 increasing the faunal density from 375 to 



2 

 9333 individuals/m (Figure 6-4, Table 6-6). These species were entirely 



absent from the station by March of 1977, apparently because of over- 

 winter mortalities. Station 6 experienced an invasion of Streblospio 

 and Gemma gemma, a small bivalve, over the summer of 1975, increasing 



densities by a factor of 10 over five months (2075 to 21888 individ- 



2 

 uals/m ) . This dense population had essentially disappeared by October 



2 



1975 when the density had declined to 125 individuals/m . 



