BUNTING, SOUTHWORTH, HERRERO, RYAN, WAYLENUnderstanding Long-Term Savanna Vegetation Persistence across Three Drainage Basins in Southern Africa

Erin L. Bunting , Jane Southworth, Hannah Herrero, Sadie J. Ryan, and Peter Waylen

Article first published online: 25 JUN 2018 Remote Sens. 2018, 10(7), 1013

DOI: 10.3390/rs10071013

ABSTRACT: Across savanna landscapes of southern Africa, people are strongly tied to the environment, meaning alterations to the landscape would impact livelihoods and socioecological development. Given the human–environment connection, it is essential to further our understanding of the drivers of savanna vegetation dynamics, and under increasing climate variability, to better understand the vegetation–climate relationship. Monthly time series of Advanced Very High-Resolution Radiometer (AVHRR)- and Moderate Resolution Imaging Spectroradiometer (MODIS) derived vegetation indices, available from as early as the 1980s, holds promise for the large-scale quantification of complex vegetation–climate dynamics and regional analyses of landscape change as related to global environmental changes. In this work, we employ time series based analyses to examine landscape-level vegetation greening patterns over time and across a significant precipitation gradient. In this study, we show that climate induced reductions in Normalized Difference Vegetation Index (NDVI; i.e., degradation or biomass decline) have had large spatial and temporal impacts across the Kwando, Okavango, and Zambezi catchments of southern Africa. We conclude that over time there have been alterations in the available soil moisture resulting from increases in temperature in every season. Such changes in the ecosystem dynamics of all three basins has led to system-wide changes in landscape greening patterns.

Read the full publication at Remote Sensing

 

 

 

 

HERRERO, SOUTHWORTH, BUNTING, CHILD – Using Repeat Photography to Observe Vegetation Change Over Time in Gorongosa National Park

HANNAH V. HERRERO, JANE SOUTHWORTH, ERIN BUNTING, and BRIAN CHILD

Article first published online: JUN 2017 African Studies Quarterly

ABSTRACT: Protected areas are important conservation tools, as they can be managed to preserve baseline ecosystem health, including that of vegetation dynamics. Understanding long-term ecosystem dynamics within a protected area enables one to understand how this static park landscape responds to outside pressure and changing drivers. In this study, a repeat photography analysis was used to analyze changes in the vegetation pattern and abundance at Gorongosa National Park in Mozambique across seventy-two years of the parks history. Archival photographs dating as far back as 1940 were selected for sites that could be relocated in a subsequent field visit in 2012. Qualitative and quantitative analysis on vegetation abundance by structural group was undertaken using Edwards’ Tabular Key. Results when comparing the photographic pairs show that, in general, tree cover has increased on average from 25 percent to 40 percent over the last seventy-two years. This 15 percent increase may be in response to environmental drivers such as human management, herbivory, fire, and precipitation. Contrary to many recent studies on shrub encroachment in southern Africa, this study finds an increase in tree cover. Such analysis and results are valuable in that they demonstrate long-term ecological change within a managed protected area.

Read the full publication at African Studies Quarterly