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

Abstract

Increasing temperatures and wildfire incidence and decreasing precipitation and river runoff in southern Africa are predicted to have a variety of impacts on the ecology, structure, and function of semi-arid savannas, which provide innumerable livelihood resources for millions of people. This paper builds on previous research that documents change in inundation and fire regimes in the Chobe River Basin (CRB) in Namibia and Botswana and proposes to demonstrate a methodology that can be applied to disentangle the effect of environmental variability from land management decisions on changing and ecologically sensitive savanna ecosystems in transboundary contexts. We characterized the temporal dynamics of vegetation productivity for the CRB using proxies of vegetation productivity and examine the relative importance of shifts in flooding and OPEN ACCESSLand 2015, 4 628 fire patterns to vegetation dynamics and effects of the association of phases of the El Niño-Southern Oscillation (ENSO) on vegetation greenness. Our results indicate that vegetation in these semi-arid environments is highly responsive to climatic fluctuations and the long-term trend is one of increased but heterogeneous vegetation cover. The increased cover and heterogeneity during the growing season is especially noted in communally-managed areas of Botswana where long-term fire suppression has been instituted, in contrast to communal areas in Namibia where heterogeneity in vegetation cover is mostly increasing primarily outside of the growing season and may correspond to mosaic early dry season burns. Observed patterns of increased vegetation productivity and heterogeneity may relate to more frequent and intense burning and higher spatial variability in surface water availability from both precipitation and regional inundation patterns, with implications for global environmental change and adaptation in subsistence-based communities.

Assessing natural resource management through integrated environmental and social-economic accounting

“…We also show that biased income allocation in favor of asset-rich households causes an unsustainable increase in demand for cattle and grazing land, explained by the cultural high value local people still attribute to owning cattle. As the Zambezi region is already at maximum carrying capacity (Mendelsohn, 2006(Mendelsohn, , 2010Pricope et al, 2015), any increase in farming land will be due to land-use change. As deforestation intensifies, the growth rate of forest stocks will decrease, which in turn may escalate pressure on households due to loss of fuel sources, shade, protection from desertification, and other ecosystem services.…”

“…Deforestation, increasing livestock headcounts, and slash-and-burn farming have contributed to the erosion and degradation of floodplains in the region (Purvis, 2002). Agriculture practices are rudimentary and are based on low-input or low-output farming, placing greater pressure on denuded land (Pricope, Gaughan, All, Binford, & Rutina, 2015). Forest resources in the area are generally undervalued and undermanaged, with few controls placed on timber and firewood collection.…”

Operationalizing Vulnerability: Land System Dynamics in a Transfrontier Conservation Area

“…Spanning a mean annual rainfall gradient of 400-1000 mm, the semi-arid savanna vegetation cover follows the gradient of an increasingly woody component with increasing mean annual rainfall [57]. However, that broad trend is disrupted by other mitigating factors such as fire and land management initiatives, grazing by wildlife and livestock, and soil-nutrient characteristics [58][59][60][61]. KAZA-TFCA is a varied landscape, both in terms of the land use and land cover but also with respect to governance.…”

Quantifying the Vegetation Health Based on the Resilience in an Arid System

“…Landsat 5 1986−1999ETM+ Landsat 7 2000−2015NO Image 1988-1994-1995-1997-1999−2006 T a b l e 1. Characterize of satellite images.…”

“…Washington-Allen et al (2008) and Cui et al (2013) examined the vegetative resilience qualitatively by plotting the mean-variance plot in Bolivia, in America and South Africa, respectively. Also, Pricope et al (2015) examined the changes in the vegetation of Savannah's landscape due to the flood and fire in South Africa qualitatively, but it is only a history of quantifying the ecological resilience using satellite images and exact mathematical equations related to the study by Washington-Allen et al (2008) on the vegetation in South Africa. is study was conducted on the total vegetation and various cover classes using TNDVI Vegetation Index and Landsat satellite images from 1972 to 1987. ree factors of amplitude, malleability and damping were examined and compared in this study on the vegetation.…”