The salt marsh bird's beak is a generalist 

 in its host preferences but a specialist in its 

 habitat requirements. It is not host specific. 

 Brian Fink (Fink and Zedler 1989) was able 

 to culture it with Distichlis spicata, 

 Monanthochloe littoralis, Salicornia 

 virginica, Frankenia grandifolia, S. 

 subterminalis, and Atriplex watsonii, with 

 growth (biomass) of the parasite declining in 

 that order. Plants accumulated more than 7x 

 the biomass with Distichlis than with Atriplex 

 watsonii. Fink was also able to culture it 

 alone, suggesting that it is a facultative 

 parasite. However, it is more likely to 

 survive without a host in the laboratory, 

 where it is watered, than in the field, where 

 soils become very saline and occasionally 

 desiccated in early summer. Experimentation 

 with and without host plants and with and 

 without salt added to the soil showed 

 significant differences. Plants were more salt 

 tolerant if grown with a host plant (Fink and 

 Zedler 1989). 



Although not host specific, the species is 

 habitat specific. It occurs in the upper salt 

 marsh in partially shaded areas that have 

 reduced soil salinity in spring and that do not 

 impound water for more than 24 hours. Tests 

 of its shade tolerance (ibid.) indicated peak 

 growth with 20% shade and significantly less 

 biomass at both 73% and 0% shade. Reduced 

 salinities increase seed germination (J. 

 Newman, U.S. Navy, Point Mugu, unpubl. 

 data). Seedlngs are sensitive to inundation, 

 however, even if the water is nonsaline (B. 

 Fink, PERL, pers. comm.). Thus, deep 

 depressions are not optimal habitats, a series 

 of rains can form pools that persist long 

 enough to kill plants. 



Flowering, pollination, and seed set are all 

 essential for long-term persistence. That the 

 seed bank can persist for at least a few years 

 is indicated by patches that reappear after a 

 year or two and by germination of seeds that 

 have been stored for no more than 9 years (B. 

 Fink, pers. comm.). Flower numbers 

 correlate well with plant biomass (R = 0.8, 

 Fink and Zedler 1989), so plants that grow 

 larger tend to allocate more resources to 

 reproduction. Pollination success is not 

 assured, though. Not all the patches that were 

 planted at Sweetwater Marsh produced seed. 



The larger patches produced more seed, 

 suggesting that the limiting factor is the 

 ability to attract suitable pollinators. 

 According to Lincoln (1985) the usual 

 pollinators are solitary bees that nest in 

 burrows in the upland. Many of these 

 peripheral habitats have been developed, 

 further restricting the potential for 

 preserving the endangered bird's beak. 

 Pollinators have not been studied at either 

 Sweetwater Marsh or Tijuana Estuary, but 

 there is a clear need to understand the linkage 

 between the upland bees and the few species of 

 salt marsh plants that are not wind- 

 pollinated. 



The light-footed clapper rail 

 (Rallus longirostris levipes) 



Because the light-footed clapper rail is 

 endangered with extinction, the U.S. Fish and 

 Wildlife Service monitors its abundance 

 throughout the region. In 1991, 34 marshes 

 were censused and birds were found in 1 1 . A 

 total of 235 pairs were censused in the 

 region, with Upper Newport Bay having the 

 largest number (128 pairs) and Tijuana 

 Estuary "in second place " (47 pairs; Zembai 

 1991). In other words, 20% of the region's 

 population occurred at this estuary in 1991. 

 The 1991 census was a new record for 

 Tijuana Estuary. The previous peak 

 population density occurred in 1983 (41 

 pairs), when cordgrass vegetation was 

 luxuriant (Chapter 5). 



The regional population of light-footed 

 clapper rails has fluctuated considerably 

 (Figure 3.31), with a noticeable drop in 

 1985. Part of the reason for that decline was 

 the 1984 nontidal period at Tijuana Estuary. 

 Before 1985, the population fluctuated 

 between 25 and 41 breeding pairs (Jorgensen 

 1975; Zembai and Massey 1981a, b). In 

 1983, Tijuana Estuary supported 17% of the 

 State's 249 breeding birds. Then, the 

 estuarine mouth closed in April 1984, and no 

 rails were seen in the March-April census of 

 1985. Recorded bird calls were also used to 

 locate territorial pairs, but none was 

 indicated. The 1984 extinction of the Tijuana 

 Estuary population was probably due to a 



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