»ws>t>i^i 



Figure 28. Patches of cordgrass have 

 invaded a pickleweed marsh which sur- 

 rounds an abandoned sewage lagoon at 

 Tijuana Estuary. Patches increased 

 in size and in number more during the 

 wet year of 1980 than in previous or 

 subsequent growing seasons. Photo by 

 J. Zedler. 



Figure 29. Prolonged flooding of the 

 San Diego River marsh, caused by 

 reservoir drawdown, leached soils of 

 their salts and allowed freshwater 

 marsh plants (e.g. cattails) to invade 

 the former salt marsh. Pickleweed, 

 shown here as dead understory plants, 

 probably died from long periods of 

 inundation. Photo by J. Zedler. 



Figure 30. Off-road vehicle activities denude tin .a I l mn 

 and alter drainage patterns. Photo by J. Zedler. 



rapact soils, 



36 



