Zagros oak forests are extended northwest to southeast of Iran, and are one of the main sinks of the atmospheric humidity and the origin of the main rivers in the region. These forests have been subject to long and intensive human use (e.g., harvesting, grazing), and are at risk from these pressures as well as increased drying due to climate change. These pressures may overwhelm the resilience of the forests and lead to vegetative collapse. This research assesses the change in composition and configuration of Zagros forest cover across apace and through time using remote sensing imagery. A sample area was selected as a typical Zagros forest landscape. A LANDSAT-2 MSS image of the area in 1976 and the synchronized LANDSAT-5 TM image of the same area in 2009 were obtained. The images were geometrically and radiometrically rectified and classified to forest, water and other land-covers to evaluate the changes in water and forest covers as the vulnerable land-covers to climate change and human utilizations.
Results/Conclusions
The results showed a 55% decrease in water and a 31% decrease in forest cover in the 33 year period; a paired binary test of changes in the number of cells for forest and water covers in two time points evaluated the decreases as highly significant (Z test, P<0.00001). A descriptive comparison of the metrics of landscape configuration shows a pronounced increase in habitat fragmentation and landscape shape irregularity through the time period. The more detailed investigation of the change in using imagery from multiple time periods will unravel the nature and trajectories of changes to assess whether these changes occurred gradually or suddenly across time and space. Assessment of these changes will help to identify the temporal and spatial location of possible vegetative changes in the oak forests, and to evaluate a link between the changes in the vegetation cover structure and potential for catastrophic shifts in Zagros ecosystems.
