NDVI Spatio-temporal Patterns and Climatic Controls Over Northern Patagonia

BIANCHI, EMILIO; VILLALBA, RICARDO; SOLARTE, ANDRÉS

ECOSYSTEMS (NEW YORK. PRINT)

SPRINGER

Lugar: Berlin; Año: 2019 vol. 23 p. 84 - 97

1432-9840

In this study, we identify the main modes of variabilityof the Normalized Difference VegetationIndex (NDVI) and their relationships with precipitationand temperature variations across northernPatagonia (36?45 S). In this approach, we combineda recently developed high-resolution griddeddataset (20 9 20 km) for temperature and precipitationwith a re-scaled NDVI grid to spatially matchthe climate database. Climate?vegetation relationshipswere analyzed taking into account a widerange of temporal variations (intra- to inter-annual)of both climate and NDVI. An EmpiricalOrthogonal Function analysis performed on NDVIdelimits four regions that are spatially consistentwith previous vegetation classifications for northernPatagonia. In addition, these coherent NDVIregions show similarities with the spatial precipitationpatterns and the temporal evolution of precipitationover the common period 2001?2010.Both NDVI and precipitation show evident annualcycles over the Mediterranean climatic region innorthwestern Patagonia. These annual cycles decreasein amplitude toward the eastern aridrangelands, and to the south on the evergreen all year-round rainforests. Significant positive relationshipsbetween monthly precipitation and NDVIare recorded in the dry temperate rangelands innortheastern Patagonia. In contrast, direct associationsbetween monthly NDVI and precipitationwere absent in the Central Patagonia cold grasslands,where seasonal interactions between precipitation,temperature and NDVI appear to bemore relevant. Relationships between NDVI andtemperature are generally weaker east of the Andes,but significantly positive in late winter/springover the temperate forests in western NorthPatagonia. Our results indicate that climate?NDVIrelationships in northern Patagonia are biomespecifics with the occurrence of temporal lags andprecipitation?temperature interactions in the responsesof vegetation to climate at some ecosystems