A Healthy Park Needs Healthy Vegetation: The Story of Gorongosa National Park in the 21st Century

Hannah Herrero,Peter Waylen,Brian Child,Jane Southworth,Reza Khatami,Di Yang

doi:10.3390/rs12030476

Abstract

Understanding trends or changes in biomass and biodiversity around conservation areas in Africa is important and has economic and societal impacts on the surrounding communities. Gorongosa National Park, Mozambique was established under unique conditions due to its complex history. In this study, we used a time-series of Normalized Difference Vegetation Index (NDVI) to explore seasonal trends in biomass between 2000 and 2016. In addition, vegetation directional persistence was created. This product is derived from the seasonal NDVI time series-based analysis and represents the accumulation of directional change in NDVI relative to a fixed benchmark (2000–2004). Trends in precipitation from Climate Hazards Group InfraRed Precipitation with Station data (CHIRPS) was explored from 2000–2016. Different vegetation covers are also considered across various landscapes, including a comparison between the Lower Gorongosa (savanna), Mount Gorongosa (rainforest), and surrounding buffer zones. Important findings include a decline in precipitation over the time of study, which most likely drives the observed decrease in NDVI. In terms of vegetation persistence, Lower Gorongosa had stronger positive trends than the buffer zone, and Mount Gorongosa had higher negative persistence overall. Directional persistence also varied by vegetation type. These are valuable findings for park managers and conservationists across the world.

Highlights

Savannas are commonly defined as grassland with scattered trees, but in practice are a mix of grass, shrub, and trees [1,2,3] which comprise over 55% of the southern African landscape, and approximately 20% of Earth’s landcover [1]
There is a corresponding decrease in Normalized Difference Vegetation Index (NDVI) over time across the entire study area
Woody savanna vegetation experienced the least decline in NDVI over time

Summary

Introduction

Savannas are commonly defined as grassland with scattered trees, but in practice are a mix of grass, shrub, and trees [1,2,3] which comprise over 55% of the southern African landscape, and approximately 20% of Earth’s landcover [1]. Savannas are controlled by key factors: precipitation, herbivory, fire, and humans [4,5,6,7]. Savannas are an important conservation landscape in southern Africa. Understanding and conserving these systems is vital as they support high faunal and floral biodiversity. Savannas are an important biome affecting the carbon cycle, supporting high human populations, and contributing 14% of global net primary productivity [8,13,14,15,16,17]. Conservation areas are a key resource in southern Africa both in terms of their ecological importance (biodiversity, biomass, carbon, etc.) and as socioeconomic drivers for the surrounding communities [18]

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Conclusion