Over 96% and 98% of the vegetated and unvegetated estuarine wetlands, respectively, have been lost over the past century and a half in the Los Angeles region. This loss is mainly attributed to conversion of wetland habitat to uplands through fill deposition or development (Stein et al. 2014).
The Ballona Wetlands Ecological Reserve (Reserve) located on the Los Angeles County coast is an example of this phenomenon, having suffered from over a century of abuse and land degradation. Historically a barbuilt estuary of over 2,100 acres (Grossinger 2010, Dark et al. 2011), the Reserve has been reduced in size to less than 600 acres of open space. Currently, only approximately one quarter of the site, (153 acres), is considered wetland habitat as delineated by Army Corps of Engineers wetland delineation methods (WRA 2011). Of the remaining wetland habitat, only a small portion (approximately 15 acres) at the western edge of the property is still tidally influenced (Medel et al. 2014).