communities, and that some species do not 

 recover from such disturbance (e.g., annual 

 pickleweed). Some areas of disturbed upland 

 should be excavated to expand the salt marsh 

 habitats and new techniques found for creating 

 fully functional ecosystems. 



Tijuana Estuary provides many 

 opportunities for restoration research that 

 can build on work done elsewhere in the 

 region. Experiments to improve cordgrass 

 transplantation using soil amendments are in 

 progress at San Diego Bay (Langis et al. 

 1991; J. Zedler, R. Langis, and K. Gibson, 

 SDSU, in progress). Work is also underway 

 to determine how best to reestablish salt 

 marsh bird's beak to Sweetwater Marsh (B. 

 Fink and J. Zedler, in progress). Pollinators 

 appear to be a limiting factor, and research is 

 needed to identify which bees are pollinators, 

 where they live, and what size patches of 

 bird's beak are needed to attract them. Very 

 little work has been done on the salt marsh 

 fauna and methods of transplanting animals 

 have not been developed. Genetic research is 

 needed to determine protocols for maintaining 

 genetic diversity in transplanted species. 

 Efforts to establish middle- and upper-marsh 

 communities have only begun; the 

 requirements of individual species and their 

 interrelationships remain to be determined. 

 Finally, the salt marsh monitoring program 

 that began in 1979 needs to be funded on a 

 permanent basis. 



The potential conflict between resource 

 management and visitor access needs to be 

 confronted, with clear priorities developed. 

 Access to salt marsh habitats needs to be 

 carefully controlled to protect resources, but 

 visitors may not be satisfied with views from 

 a distance. Data on responses of birds to 

 disturbance (e.g., White 1986) need to be 

 incorporated into planning for trails. Plans to 

 construct a bridge across the East-West 

 Channel, which would open remote areas of 

 salt marsh and endangered species habitat to 

 foot and vehicle traffic (Dobbin Associates 

 1986) should be revised. The channel became 

 wider and the banks less stable, after dike 

 breaching improved water circulation in the 

 tidal ponds upstream. More important, the 

 ecological communities and endangered species 



that would be affected by increased human use 

 have not yet recovered from past trampling. 



• Salt pannes. The natural values of salt 

 pannes are not often recognized, and proposals 

 are often made to convert them to other uses. 

 During both the wet and dry phases, salt 

 pannes are important areas for insects, 

 including rove beetles and mudflat tiger 

 beetles. When inundated, the areas serve as 

 feeding grounds for migrant and resident 

 birds. Species associated with the intertidal 

 salt marsh and the transition to upland also 

 use these areas. 



Lack of quantitative information about 

 their habitat value limits our ability to 

 manage and restore them. Another continuing 

 problem in salt pannes is the compaction of 

 soils caused by vehicle and foot traffic. 

 Research is needed to quantify the 

 communities of organisms that use salt pannes 

 throughout the annual wet/dry cycle, building 

 on the preliminary work of Nordby (1984). 



Brackish marsh. Areas that have 

 reduced salinities throughout most of the year 

 are currently maintained by rainfall and 

 urban runoff. Although artificial in this 

 sense, they do support an ecosystem with 

 species native to the area. Elsewhere in the 

 region, brackish marshes are valued for their 

 augmentation of habitat for populations of 

 clapper rails, black-necked stilts, snowy 

 egrets, and other birds. They also increase 

 habitat diversity at the estuary and attract 

 species that would not otherwise occur there 

 (e.g., red-winged blackbirds). 



The management problem associated with 

 brackish marsh is their potential expansion at 

 the expense of saline wetlands. Freshwater 

 runoff leaches soils of salts, and the brackish 

 marsh species expand and displace those of the 

 salt marsh. Where exotic weeds (such as 

 brass buttons) and horticultural escapes 

 establish, the expansion of brackish 

 conditions detracts from the basic habitat 

 management goal of maintaining natural 

 habitats. 



Curtailing the daily flows of sewage into 

 Tijuana Estuary was a major improvement in 

 brackish marsh control. Next, tidal 



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