Comparisons of productivity numbers 

 with eastern marshes did not seem very 

 profitable once we discovered how variable 

 the marsh was in both biomass and 

 composition. Tijuana Estuary, and probably 

 all southern California marshes (cf. data for 

 Los Peftasquitos Lagoon in Zedler et al. 1980), 

 were found to differ greatly from year to year. 

 Understanding how and why individual 

 marshes differ in time became a more 

 promising research goal (Chapter 5). 



Winfield (1980) showed that cordgrass 

 productivity was relatively high among the 

 salt marsh species, but it contributed less 

 than half that of the entire marsh (Table 4.4). 

 His sampling scheme began with 46 randomly 

 sampled stations within a 0.8 ha area of the 

 marsh. More stations were added for the 

 August sample (n = 56), then cut to 25 

 stations in 1977. At each station, plants were 

 clipped to ground level within 0.25-m2 

 circular quadrats. 



Frequent sampling (Table 4.5) showed 

 that there were differences in the timing of 



peak standing crop for each species. 

 Pickleweed reached its maximum in August, 

 while cordgrass peaked in July and again in 

 September following fruit production. The 

 standing crop for all species combined was at 

 its minimum in March and maximum in 

 August of 1976 and 1977 (Figure 4.4). 

 Whole-marsh sampling was repeated in 

 August of 1978, but efforts in later years 

 were restricted to the lower marsh (Figure 

 4.3). 



In both 1976 and 1977, standing crops 

 doubled between March and August, but even 

 in March, substantial live biomass was 

 present (Figure 4.4). The criterion for 

 "live" biomass was any stem with green 

 material attached to it. Much of the live 

 winter biomass consisted of fibrous shore 

 grass, second-year cordgrass, and woody 

 pickleweed stems. Despite large mortality 

 between August and March, the standing dead 

 biomass remained relatively constant. Thus, 

 dead stems and leaves were rapidly 

 incorporated into litter, exported, or 

 decomposed. 



Table 4.5. Standing crop (g dry wt/rm 2 ) of major salt marsh vascular plants for 

 March (minimum biomass) 1976, 1977 and August (biomass peak) in 1976, 1977, 

 and 1978 (from Winfield 1980). 



Species 



3/76 8/76 3/77 8/77 8/78 



Batis maritima, saltwort 



Jaumea carnosa 



Monanthochloe littoralis, shore grass 



Salicornia bigelovii, annual pickleweed 



S. virginica, pickleweed 



Spartina foliosa, cordgrass 



Total standing crop 



426 



858 



514 1153 



954 



a Jaumea and shore grass were not separated in the March 1976 sample. 



87 



