The MODIS Global Vegetation Fractional Cover Product 2001–2018: Characteristics of Vegetation Fractional Cover in Grasslands and Savanna Woodlands

Michael J Hill,Juan P Guerschman

doi:10.3390/rs12030406

Michael J Hill, Juan P Guerschman

Open Access

https://doi.org/10.3390/rs12030406

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Journal: Remote sensing	Publication Date: Jan 28, 2020
Citations: 31	License type: CC BY 4.0

Affiliation: CSIRO Land and Water, University of North Dakota

Abstract

Vegetation Fractional Cover (VFC) is an important global indicator of land cover change, land use practice and landscape, and ecosystem function. In this study, we present the Global Vegetation Fractional Cover Product (GVFCP) and explore the levels and trends in VFC across World Grassland Type (WGT) Ecoregions considering variation associated with Global Livestock Production Systems (GLPS). Long-term average levels and trends in fractional cover of photosynthetic vegetation (FPV), non-photosynthetic vegetation (FNPV), and bare soil (FBS) are mapped, and variation among GLPS types within WGT Divisions and Ecoregions is explored. Analysis also focused on the savanna-woodland WGT Formations. Many WGT Divisions showed wide variation in long-term average VFC and trends in VFC across GLPS types. Results showed large areas of many ecoregions experiencing significant positive and negative trends in VFC. East Africa, Patagonia, and the Mitchell Grasslands of Australia exhibited large areas of negative trends in FNPV and positive trends FBS. These trends may reflect interactions between extended drought, heavy livestock utilization, expanded agriculture, and other land use changes. Compared to previous studies, explicit measurement of FNPV revealed interesting additional information about vegetation cover and trends in many ecoregions. The Australian and Global products are available via the GEOGLAM RAPP (Group on Earth Observations Global Agricultural Monitoring Rangeland and Pasture Productivity) website, and the scientific community is encouraged to utilize the data and contribute to improved validation.

Highlights

Vegetation Fractional Cover (VFC) is an important global indicator of land cover change, land use practice, and landscape and ecosystem function [1,2]
The distribution of long-term average FNPV tends to highlight the large grasslands of North America, South America, central Eurasia, Tibet, Mongolia, and the savannas of southern Africa and Australia (Figure 2)
There is a notable rise in FNPV between 20 and 40◦ N which may reflect the large expanses of steppe environments either limited by precipitation or converted to cereal cropping

Summary

Introduction

Vegetation Fractional Cover (VFC) is an important global indicator of land cover change, land use practice, and landscape and ecosystem function [1,2]. The Australian Vegetation Fractional Cover Product (AVFCP) is derived from the 500 m MODIS (MODerate Resolution Imaging Spectroradiometer) NBAR (Nadir BRDF-adjusted Reflectance) product (MCD43A4) and has been comprehensively documented, validated, and improved over several versions [3,4,5,6]. We present the Global Vegetation Fractional Cover Product (GVFCP) based on the same methodology. Both the Australian and Global products are available through the GEOGLAM RAPP

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Results

Conclusion