Dynamics of fire, precipitation, vegetation and NDVI in dry forest environments in NW Argentina.

PALACIO P.I.; LINDSKOUG H.B.; BURRY L.S.; TRIVI M.E.; D´ANTONI H.L. ; BURRY L.S.; TRIVI M.E.; D´ANTONI H.L. ; SOMOZA M.; MARCONETTO M.B.; SOMOZA M.; MARCONETTO M.B.; PALACIO P.I.; LINDSKOUG H.B.

JOURNAL OF ARCHAEOLOGICAL SCIENCE

ACADEMIC PRESS LTD-ELSEVIER SCIENCE LTD

Lugar: Manchester; Año: 2018 p. 747 - 757

2352-409X

Fire has shaped the environment and has been important for human cultural development. In this paper, we proposeto study past fire events using ecological modelling. For instance, the ecology of fire can help us to understand andinterpret archaeological problems related to past settlement patterns or environmental scenarios. Variation in fireregimens are related to both, vegetation and precipitation fluctuations. Recently we have model past ecosystemdynamics using remote sensing in the Ambato Valley (Catamarca NW Argentina) ranging from 442-1998 AD. Our aimhere is to use remotely sensed vegetation data to enhance our understanding of environmental disturbance in theperiod 2000-2011. We characterized the spatial-time dynamics of the annual NDVI as an indicator of vegetationfunctioning. Then we related the NDVI dynamics to precipitation and fire events in an arid highland environment in thearea. Further, we analysed the vegetation data (monthly NDVI, MODIS/TERRA satellite, 1km2 pixels), and the climatedata: annual precipitation. Then we calculated the NDVI annual average of every pixel and the NDVI anomalies ofevery year over the studied period. Lastly, we related NDVI data with annual precipitation and compared the NDVIsprior to and after known fire events in this period. On a spatial scale, the results show that the NDVI values were (a)low in shrublands and in cultivated areas, (b) medium in grasslands and piedmont forest with anthropic impact, and (c)high in highland forests. Within the studied time-period, extreme positive and negative anomalies were detected. Theprecipitation inter-annual variations were greater than the NDVI inter-annual variations, thus demonstrating that insome areas of the valley the horizontal precipitation can make important contributions to the ecosystem humidity.Extreme negative anomalies were observed the year of fire and fire scars at least for the next two years. These resultsdemonstrate the relation between structure and function of vegetation, precipitation and fire. Understanding theserelations can enable us to explain results when hindcasting (?predicting? what happened during past episodes ofclimate change) palaeoenvironmental conditions and fire events, thus helping us to interpret different archaeologicalcontexts related to fire events.