Abstract
High‐latitude areas are experiencing rapid change: we therefore need a
better understanding of the processes controlling soil erosion in these
environments. We used a spatiotemporal approach to investigate soil
erosion in Svalbarðstunga, Iceland (66°N, 15°W), a degraded rangeland.
We used three complementary datasets: (a) high‐resolution
unmanned‐aerial vehicle imagery collected from 12 sites (total area
~0.75 km2); (b) historical imagery of the same sites; and (c)
a simple, spatially‐explicit cellular automata model. Sites were
located along a gradient of increasing altitude and distance from the
sea, and varied in erosion severity (5–47% eroded). We found that there
was no simple relationship between location along the environmental
gradient and the spatial characteristics of erosion. Patch‐size
frequency distributions lacked a characteristic scale of variation, but
followed a power‐law distribution on five of the 12 sites. Present total
eroded area is poorly related to current, site‐scale levels of
environmental stress, but the number of small erosion patches did
reflect site‐level stress. Small (<25 m2) erosion patches
clustered near large patches. The model results suggested that the
large‐scale patterns observed likely arise from strong, local
interactions, which mean that erosion spreads from degraded areas. Our
findings suggest that contemporary erosion patterns reflect historical
stresses, as well as current environmental conditions. The importance of
abiotic processes to the growth of large erosion patches and their
relative insensitivity to current environmental conditions makes it
likely that the total eroded area will continue to increase, despite a
warming climate and reducing levels of grazing pressure.
Original language | English |
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Journal | Land Degradation & Development |
Volume | Early View |
Early online date | 10 Mar 2020 |
DOIs | |
Publication status | E-pub ahead of print - 10 Mar 2020 |
Keywords
- UAV
- Grazing
- Patch-size distributions
- Soil erosion
- Iceland
- Sheep
- Cellular automata