Proper management of natural ecosystems is not possible without the knowledge of the health status of its components. Vegetation, as the main component of the ecosystem, plays an important role in its health. One of the key determinants of vegetation health is its resilience in the face of environmental disorders. This research was conducted in parts of the Namakzar-e Khaf watershed in Northeast of South Khorasan Province with the aim of quantifying the vegetative resilience on behalf of the ecosystem health in response to long-term precipitation changes. First, the annual precipitation standardization was performed during a thirty-year period by the SPI method. Then, the average variation in TNDVI index obtained from the Landsat satellite images was examined and the resilience was tested by calculating the four effective factors (amplitude, malleability, damping and hysteresis). According to the results, the amplitude in the survey period was 6.04% and the vegetation has had different values of damping over the years. The most prominent example of vegetation resilience occurred between 1986 and 1996, with malleability of 0.7 and damping of zero. Vegetation in this period, after the elimination of drought effects (1986), has not only returned to the amount of vegetation of reference year with severe precipitation (1996) but also increased by 0.25%. This increase, as the index of hysteresis, has been presented for the first time in the ecosystem health discussion quantitatively in the present study. A set of quantitative calculations showed that despite reduced annual precipitation and drought events, the vegetation has been able to maintain its resilience, which indicates the health of vegetation in the studied ecosystem.
Abrahams, A.D., Parsons, A.J. & Wainwright J. (1995). Effects of vegetation change on interrill runoff and erosion, Walnut Gulch, southern Arizona. Geomorphology, 13, 37−48. DOI: 10.1016/0169-555X(95)00027-3.
Carpenter, S.R., Walker, B.H., Anderies, J.M. & Abel N. (2001). From metaphor to measurement: Resilience of what to what? Ecosystems, 4, 765–781. DOI: 10.1007/s10021-001-0044-9.
Cui, X., Gibbes, C., Southworth, J. & Waylen P. (2013). Using remote sensing to quantify vegetation change and ecological resilience in a semi-arid system. Journal of Land, 2, 108–130. DOI: 10.3390/land22020108.
Elmqvist, T., Folke, C., Nystrom M., Peterson, G., Bengtsson, J., Walker, B. & Norberg J. (2003). Response diversity, ecosystem change, and resilience. Frontiers in Ecology and the Environment, 1, 488−494. DOI: 10.1890/15409295(2003)001[0488:RDECAR]3.0.CO;2.
Farrar, T.J., Nicholson, S.E. & Lare A.R. (1994). The influence of soil type on the relationships between NDVI, rainfall, and soil moisture in semiarid Botswana. II. NDVI response to soil moisture. Remote Sens. Environ., 50, 121–133. DOI: 10.1016/0034-4257(94)90039-6.
Friend, R. & Moench M. (2013). What is the purpose of urban climate resilience? Implications for addressing poverty and vulnerability. Urban Climate, 6, 98–113. DOI: 10.1016/j.uclim.2013.09.002.
Goheen, J., Young, T., Keesing, F. & Palmer T. (2007). Consequences of herbivory by native ungulates for the reproduction of a savanna tree. J. Ecol., 95, 129–138. DOI: 10.1111/j.1365-2745.2006.01196.x.
Griffiths, B.S. & Philippot L. (2013). Insights into the resistance and resilience of the soil microbial community. FEMS Microbiol. Rev., 37, 112–129. DOI: 10.1111/j.15746976.2012.00343.x.
Gunderson, L.H. & Holling C.S. (2002). Panarchy: Understanding transformations in human and natural systems. Washington: Island Press.
Holling, C.S. (1973). Resilience and stability of ecological systems. Annu. Rev. Ecol. Syst., 4, 1–23. DOI: 10.1146/annurev.es.04.110173.000245.
Holling, C.S. (1986). The resilience of terrestrial ecosystems: Local surprise and global change. In W.C. Clark & R.E. Munn (Eds.), Sustainable development of the biosphere (pp. 292−320). Cambridge: Cambridge University Press.
Kasperson, R.E. & Kasperson J.X. (2001). Climate change, vulnerability and social justice. Stockholm: Stockholm Environment Institute.
Martiny, N., Camberlin, P., Richard, Y. & Philippon N. (2006). Compared regimes of NDVI and rainfall in semi-arid regions of Africa. Int. J. Remote Sens., 27, 5201–5223. DOI: 10.1080/01431160600567787.
Puigdefábregas, J. & Sánchez G. (1996). Geomorphological implications of vegetation patchiness on semi-arid slopes. In M.G. Anderson & S.M. Brooks (Eds.), Advances in hillslope processes (pp. 1027–1060). Wiley.
Pricope, N.G., Gaughan, A.E., All, J.D., Binford, M.W. & Rutina L.P. (2015). Spatio-temporal analysis of vegetation dynamics in relation to shifting inundation and fire regimes: Disentangling environmental variability from Land management decisions in a Southern African transboundary watershed. Land, 4, 627−655. DOI: 10.3390/land4030627.
Richard, Y. & Poccard I. (1998). A statistical study of NDVI sensitivity to seasonal and interannual rainfall variations in Southern Africa. Int. J. Remote Sens., 19, 2907–2920. DOI: 10.1080/014311698214343.
Ringrose, S., Matheson, W., Tempest, F. & Boyle T. (1990). The development and causes of range degradation features in southeast Botswana using multi-temporal Landsat MSS imagery. Photogrammetric Engineering and Remote Sensing, 56, 1253–1262.
Rockström, J. (2003). Resilience building and water demand management for drought mitigation. Physics and Chemistry of the Earth, 28, 869–877. DOI: 10.1016j.pce.2003.08.009.