Coastal Wetlands of the Bahía Blanca Estuary: Landscape Structure and Plant Associations

Abstract

Landscape structure in the coastal zone of Bahía Blanca is a result of the marine transgression that affected the area during the Holocene. Storm deposits corresponding to the transgressive maximum are widespread along the northern and western margin of the estuary and set the limits to the area considered in this chapter. Based on geomorphic maps, different landscape units were identified and further characterized by their hydrogeomorphic conditions. Tidal and groundwater influences on the soil surface are the primary drivers of soil properties and vegetation structure. Within the intertidal zone, there are two different types of plant associations. Salt marshes of Spartina alterniflora are typical landscape components in the middle reach of the Principal Channel. They commonly occupy elevations lower than the mean high tide, from Ingeniero White to Puerto Rosales. Through the inner section of the Principal Channel, these marshes are less common, and the dominant species is Sarcocornia ambigua, which forms marshes at a higher elevation within the tidal fringe. Above the limits of tidal influence, other plant associations were described. Significant land cover changes and landscape trends were identified over the last decades, and their effects on ecosystem functions were discussed. Text boxes contain additional information on emblematic plant species in the area.