Impacts of Drought Severity and Frequency on Natural Vegetation Across Iran
Drought recurrence is increasing in arid and semi-arid regions, and its effects are becoming more complicated due to climate change. Despite the increasing frequency of drought events, the sensitivity of natural vegetation to different levels of drought frequency and severity is not fully underst...
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| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Philipps-Universität Marburg
2024
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| Subjects: | |
| Online Access: | PDF Full Text |
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| Summary: | Drought recurrence is increasing in arid and semi-arid regions, and its effects are becoming
more complicated due to climate change. Despite the increasing frequency of drought events, the
sensitivity of natural vegetation to different levels of drought frequency and severity is not fully
understood. Here, we aim to characterize the regional spatio-temporal patterns of drought frequency
and severity and the response of vegetation across Iran at a high spatial resolution (5 km × 5 km).
We examined the responses of three natural vegetation types (forest, grassland, and shrubland) to
drought conditions across Iran using the Normalized Difference Vegetation Index (NDVI) and the
Standardized Precipitation Evapotranspiration Index (SPEI) at different time scales and temporal
lags from 2001 to 2022. Our results showed that drought severity increased in 15%, decreased in 1%,
and remained stable in 84% of the study area. The severity and frequency of drought showed spatial
patterns across Iran (i.e., increased from northwest to southeast and central Iran). The correlation
between the monthly NDVI anomaly and SPEI varied across vegetation types, SPEI accumulation
period (SPEI-1-3-6-9-12), and temporal lags, revealing different sensitivities of vegetation to drought
in Iran. All natural vegetation types showed the strongest responses two months after drought events.
Forests, mostly located in northern Iran, showed lower sensitivity to drought onset and responded
slower to drought severity than other vegetation classes (i.e., grasslands and shrublands). These
findings highlight the importance of analyzing the sensitivity of natural vegetation at different levels
of drought severity and frequency for land use planning and mitigation efforts. |
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| Item Description: | Gefördert durch den Open-Access-Publikationsfonds der UB Marburg. |
| DOI: | 10.3390/w16223334 |