Vegetation productivity trends in response to urban dynamics

GIOIA, ANTONELA; ARÁOZ, EZEQUIEL; ARÁOZ, EZEQUIEL; PAOLINI, LEONARDO; POWELL, PRISCILA; PAOLINI, LEONARDO; POWELL, PRISCILA; GIOIA, ANTONELA

URBAN FORESTRY & URBAN GREENING

ELSEVIER GMBH

Año: 2016 vol. 17 p. 211 - 216

1618-8667

The urbanization of the human population is a global phenomenon with still unknown consequences for vegetation dynamics of urban ecosystems, especially in subtropical areas of developing countries. In this paper we analyze the vegetation productivity trend associated to urban growth during the last decade, in twelve urban areas of northern Argentina. We use time series analysis of MODIS-NDVI images to reconstruct the phenological patterns to retrieve productivity trend under three differents treatments representative of urban growth dynamics: 1) Urban, 2) Expansion and 3) Exurban areas. Our results show that the trends in vegetation productivity are more associated to the environmental characteristics (basal productivity and climate) than to the treatments. The average trend in productivity in urban areas ranged between -2.54% year-1 (Metán city) and -0.22% year-1 (Concepción city). In contrast, the range was much tighter between conditions; it was -1.37% year-1 in urban areas and -1.21% in peripheric areas. In this sense we found significant differences between some urban areas, but no significant differences were observed between treatments. Population increase and urban growth patterns found in our study suggest a sprawl patterns of growth, which is consistent with modern urban dynamics models. Related to this phenomenon, our results dismissed the idea of urban expansion as a main factor that affects vegetation dynamic and support the hypothesis of local/regional warming as an explanation for the decreasement of vegetation productivity, due to the increase of plant´s hydric stress in hot and arid regions.