Journal of Geographical Sciences ›› 2014, Vol. 24 ›› Issue (5): 815-832.doi: 10.1007/s11442-014-1122-2

• Research Articles • Previous Articles     Next Articles

Detecting climate change effects on forest ecosystems in Southwestern Romania using Landsat TM NDVI data

PRAVALIE Remus1(), SÎRODOEV Igor2(), PEPTENATU Daniel3()   

  1. 1. Bucharest University - Faculty of Geography, 14-12 Nicolae Bălcescu Str., Romania
    2. Institute of Ecology and Geography, Moldavian Academy of Sciences, Republic of Moldova
    3. Bucharest University - Interdisciplinary Center for Advanced Research on Territorial Dynamics, 3-12 Regina Elisabeta Str., Bucharest, Romania
  • Received:2013-08-12 Accepted:2014-02-12 Online:2014-05-20 Published:2015-07-10
  • About author:

    Author: Remus Pravalie, E-mail: pravalie_remus@yahoo.com; Igor Sîrodoev, E-mail: ingvarr_i@yahoo.com; Daniel Peptenatu, E-mail: peptenatu@yahoo.fr

Abstract:

Nowadays, Southwestern Romania faces a large-scale aridization of the climate, revealed by the rise of temperatures and the decline of the amount of precipitations, with negative effects visible, among others, in the desiccation of forest vegetation. The present study means to identify the changes that occurred, quality-wise, in the past two decades (1990-2011) in forest vegetation in Southwestern Romania, and to establish the link between those changes and extant thermal stress in the region, whose particular features are high average annual and seasonal temperatures. In order to capture the evolution in time of climate aridization, a first step consisted in using climate data, the temperature and precipitation parameters from three weather stations; these parameters were analyzed both individually and as aridity indexes (De Martonne and UNEP). In order to quantify the changes in forest vegetation, NDVI indexes were used and analyzed, starting off from Landsat satellite images, acquired at three distinct moments in time, 1990, 2000 and 2011. In order to identify the link between the changes of NDVI index values and regional thermal stress, a yardstick of climate changes, statistical correlations were established between the peak values of average annual temperatures, represented in space, and negative changes in the NDVI index, as revealed by the change-detection analysis. The results obtained indicated there is an obvious (statistically significant) connection between thermal stress and the desiccation (degradation) of forest species in the analyzed area, with false acacia (Robinia Pseudoacacia) the main species to be impacted.

Key words: thermal stress, forest ecosystems, NDVI index, change detection analysis