Plant diversity along the urbanization gradient in coastal resorts from Argentina

FAGGI A & J. DADON

Bariloche

Congreso; Southern Connection; 2010

Southern Connection

The urbanization is one of the major factors in the homogenization of the biota. As new and fast growing cities, the coastal resorts are interesting models to study the vegetation changes promoted by urban processes. In order to analyze these changes, seven coastal resorts were chosen: Villa Gesell, Miramar, Necochea, Monte Hermoso, Las Grutas and Puerto Madryn. Three sectors were defined in each city: downtown area, residential area with continuous urban fabric, and residential area with disperse urbanization. Ten blocks were sampled in each sector, discriminating among different patches: lawns and trees along the streetscapes, gardens, vegetated dunes and brownfields. Total richness, native/exotic index, implanted/spontaneous index and coverage per species were registered in all cases. Total richness was high, since 387 species were recorded; 62% were exotics; 37% implanted. Twenty two implanted species grew spontaneously, 94 plants were characteristic for the dunes and 116 are pastures species. The vegetation of the lawns in the central and residential areas showed the higher plant diversity, while the dunes showed the lower diversity. The richness increased towards the center in some cases and it decreased towards the periurban areas in other. Since these trends changed among different patches inside the same resort, the factors that controlled changes in richness were not clear. A higher proportion of introduced ornamental exotic species were found in the brownfields, dunes and lawns without maintenance, indicating that unplanned changes contributed to increase the homogenization of the biota inside the cities.