Volume 163, 15 June 2015, Pages 312–325
Mapping farmland abandonment and recultivation across Europe using MODIS NDVI time series
Highlights
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- Mapping active and fallow farmland across Europe using MODIS NDVI time series
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- Translating land-use information into management intensity and land-use change trajectories
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- Approach allows various definitions of farmland abandonment and recultivation.
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- Farmland abandonment continues to be a crucial land change process in Europe.
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- Recultivation of unused farmland increasingly outweighs farmland abandonment.
Abstract
Farmland
abandonment is a widespread land-use change in temperate regions, due
to increasing yields on productive lands, conservation policies, and the
increasing imports of agricultural products from other regions.
Assessing the environmental outcomes of abandonment and the potential
for recultivation hinges on incomplete knowledge about the spatial
patterns of fallow and abandoned farmland, especially at broad
geographic scales. Our goals were to develop a methodology to map active
and fallow land using MODIS Normalized Differenced Vegetation Index
(NDVI) time series and to provide the first European-wide map of the
extent of abandoned farmland (cropland and grassland) and recultivation.
We used a geographically well-distributed training dataset to classify
active and fallow farmland annually from 2001 to 2012 using a Random
Forests classifier and validated the maps using independent observations
from the field and from satellite images. The annual maps had an
average overall accuracy of 90.1% (average user's accuracy of the fallow
class was 73.9%), and we detected an average of 128.7 million hectares
(Mha) of fallow land (24.4% of all farmland). Using the fallow/active
time series, we mapped fallow frequency and hotspots of farmland
abandonment and recultivation of unused farmland. We found a total of
46.1 Mha of permanently fallow farmland, much of which may be linked to
abandonment that occurred after the dissolution of the Eastern Bloc. Up
to 7.6 Mha of farmland was additionally abandoned from 2001 to 2012,
mainly in Eastern Europe, Southern Scandinavia, and Europe's mountain
regions. Yet, recultivation is widespread too (up to 11.2 Mha) and
occurred predominantly in Eastern Europe (e.g., European Russia, Poland,
Belarus, Ukraine, and Lithuania) and in the Balkans. We also tested the
robustness of our maps in relation to different abandonment and
recultivation definitions, highlighting the usefulness of time series
approaches to overcome problems when mapping transient land-use change.
Our maps provide, to our knowledge, the first European-wide assessment
of fallow, abandoned and recultivated farmland, thereby forming a basis
for assessing the environmental outcomes of abandonment and
recultivation and the potential of unused land for food production,
bioenergy, and carbon storage.
Keywords
- Farmland abandonment;
- Europe;
- Fallow farmland;
- Land-use change;
- Management intensity;
- MODIS time series;
- Random Forests classifier;
- Recultivation
- Corresponding author. Tel.:
+ 49 30 2093 9341; fax: + 49 30 2093 6848.
Copyright © 2015 Elsevier Inc. All rights reserved.
