Climate and land-use change in field-crop ecosystems of Argentina

In line with a worldwide trend, statistical records in the Argentine Pampas show that cultivated lands increased greatly in the last century at the expense of natural areas. However, very little is known about the factors causing this. Our hypothesis was that climate was the main factor associated with land-use change in a high time-space scale, but factors other than climate would-have to be considered in a scaling down analysis, The purposes of this work were (a) to study the dynamics of climate and land-use in the last century and across the Pampas plain, (b) to quantify the impact of climate on land-use change, and (c) to discuss the applicability of the results to guide adaptive land-use strategies. A broad transect was displayed along the underlying rainfall gradient to make along-term analysis in different agroecological environments across the study region. Different statistical and research data sources were utilised, and simple regression analysis using Linear and nonlinear models were applied. The results suggested that the original hypothesis had to be revised. In humid environments, the degree of association between climate and land-use change along the time axis was high, but this association declined in the transition from the humid to the semiarid zones. This suggested that factors other than climate, such as technology, could also explain a considerable part of land-use variability. On the other hand, the association between climate and land-use was very low across a wide geographic scale within a specific period of time. Thus, this association seems to be a site-specific and a time-dependent function, specially for the humid zones, and suggests that our former hypothesis can be accepted only in part. These results are necessary to guide land-use adaptive strategies in response to potential changes in the climate scenario. (C) 1997 Elsevier Science B.V.