Woody and Herbaceous Vegetation Change across the Savannas of West Africa, 1982-2013

The WAVeTrends dataset is a 0.05 degree (5.55 km) vegetation change product, spanning the West African Sudano-Sahel region. It provides pixel-wise information on concurrent woody and herbaceous vegetation trends over a 32-year period (1982-2013). Change in woody vegetation was derived using long-term rain use efficiency (RUE) sensitivity, i.e., the per-pixel comparison of the difference of mean RUE between the first and last decades of the 32-year time series. Herbaceous vegetation change was defined by short-term RUE sensitivity, i.e., comparing the slope of the RUE relationship (productivity vs. precipitation) between both decades using per-pixel Analysis of Covariance (ANCOVA). Categorical vegetation change was then determined for each pixel using the direction of the change and a significance level of p<0.05. The use of RUE (the amount of biomass produced per unit of precipitation) for vegetation trend analysis in savanna regions relies on the assumption that rainfall is a significant positive driver of net production in drylands. Testing of this long-term productivity-rainfall relationship revealed that the assumption was not always met, therefore, validity flags are included for each pixel location.

Data and Resources

Field Value
accessLevel public
bureauCode {026:00}
catalog_@context https://project-open-data.cio.gov/v1.1/schema/catalog.jsonld
catalog_@id https://data.nasa.gov/data.json
catalog_conformsTo https://project-open-data.cio.gov/v1.1/schema
catalog_describedBy https://project-open-data.cio.gov/v1.1/schema/catalog.json
citation Anchang, J.Y., L. Prihodko, A.T. Kaptue, C.W. Ross, W. Ji, S.S. Kumar, B. Lind, M.A. Sarr, A.A. Diouf, and N.P. Hanan. 2020. Woody and Herbaceous Vegetation Change across the Savannas of West Africa, 1982-2013. ORNL DAAC, Oak Ridge, Tennessee, USA. https://doi.org/10.3334/ORNLDAAC/1738
graphic-preview-description Concurrent woody and herbaceous vegetation changes between the 1982-1991 and 2004-2013 decades of the Sudano-Sahel region of Africa. (A) Map of vegetation change categories. (B) Chart showing the conceptual position and the relative abundance of each category in a 2-D space (Anchang et al. 2019).
graphic-preview-file https://daac.ornl.gov/VEGETATION/guides/WAVeTrends_Fig1.png
identifier C1739085532-ORNL_DAAC
issued 2020-05-07
landingPage https://doi.org/10.3334/ORNLDAAC/1738
language {en-US}
metadata_type geospatial
modified 2020-05-08
programCode {026:001}
publisher ORNL_DAAC
resource-type Dataset
source_datajson_identifier true
source_hash e5db25a10e1ae9e5892b8b34ef24dd3fa18e88ea
source_schema_version 1.1
spatial {"type": "Polygon", "coordinates": [[[-17.14, 9.96], [15.31, 9.96], [15.31, 17.41], [-17.14, 17.41], [-17.14, 9.96]]]}
temporal 1982-01-01T00:00:00Z/2013-12-31T23:59:59Z
theme {Vegetation,geospatial}
Groups
  • AmeriGEOSS
  • National Provider
  • North America
Tags
  • amerigeo
  • amerigeoss
  • atmosphere
  • biosphere
  • ckan
  • earth-science
  • ecological-dynamics
  • ecosystems
  • geo
  • geoss
  • habitat-conversion-fragmentation
  • human-dimensions
  • national
  • north-america
  • precipitation
  • united-states
  • vegetation
isopen False
license_id notspecified
license_title License not specified
maintainer undefined
maintainer_email uso@daac.ornl.gov
metadata_created 2025-11-22T13:53:44.289768
metadata_modified 2025-11-22T13:53:44.289771
notes The WAVeTrends dataset is a 0.05 degree (5.55 km) vegetation change product, spanning the West African Sudano-Sahel region. It provides pixel-wise information on concurrent woody and herbaceous vegetation trends over a 32-year period (1982-2013). Change in woody vegetation was derived using long-term rain use efficiency (RUE) sensitivity, i.e., the per-pixel comparison of the difference of mean RUE between the first and last decades of the 32-year time series. Herbaceous vegetation change was defined by short-term RUE sensitivity, i.e., comparing the slope of the RUE relationship (productivity vs. precipitation) between both decades using per-pixel Analysis of Covariance (ANCOVA). Categorical vegetation change was then determined for each pixel using the direction of the change and a significance level of p<0.05. The use of RUE (the amount of biomass produced per unit of precipitation) for vegetation trend analysis in savanna regions relies on the assumption that rainfall is a significant positive driver of net production in drylands. Testing of this long-term productivity-rainfall relationship revealed that the assumption was not always met, therefore, validity flags are included for each pixel location.
num_resources 7
num_tags 17
title Woody and Herbaceous Vegetation Change across the Savannas of West Africa, 1982-2013