Regional and landscape-scale variability of Landsat-observed vegetation dynamics in northwest Siberian tundra
Widespread increases in Arctic tundra productivity have been documented for decades using coarse-scale satellite observations, but finer-scale observations indicate that changes have been very uneven, with a high degree of landscape- and regional-scale heterogeneity. Here we analyze time-series of t...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
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IOP Publishing
2014-01-01
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| Series: | Environmental Research Letters |
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| Online Access: | https://doi.org/10.1088/1748-9326/9/2/025004 |
| _version_ | 1797747999576686592 |
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| author | Gerald V Frost Howard E Epstein Donald A Walker |
| author_facet | Gerald V Frost Howard E Epstein Donald A Walker |
| author_sort | Gerald V Frost |
| collection | DOAJ |
| description | Widespread increases in Arctic tundra productivity have been documented for decades using coarse-scale satellite observations, but finer-scale observations indicate that changes have been very uneven, with a high degree of landscape- and regional-scale heterogeneity. Here we analyze time-series of the Normalized Difference Vegetation Index (NDVI) observed by Landsat (1984–2012), to assess landscape- and regional-scale variability of tundra vegetation dynamics in the northwest Siberian Low Arctic, a little-studied region with varied soils, landscape histories, and permafrost attributes. We also estimate spatio-temporal rates of land-cover change associated with expansion of tall alder ( Alnus ) shrublands, by integrating Landsat time-series with very-high-resolution imagery dating to the mid-1960s. We compiled Landsat time-series for eleven widely-distributed landscapes, and performed linear regression of NDVI values on a per-pixel basis. We found positive net NDVI trends (‘greening’) in nine of eleven landscapes. Net greening occurred in alder shrublands in all landscapes, and strong greening tended to correspond to shrublands that developed since the 1960s. Much of the spatial variability of greening within landscapes was linked to landscape physiography and permafrost attributes, while between-landscape variability largely corresponded to differences in surficial geology. We conclude that continued increases in tundra productivity in the region are likely in upland tundra landscapes with fine-textured, cryoturbated soils; these areas currently tend to support discontinuous vegetation cover, but are highly susceptible to rapid increases in vegetation cover, as well as land-cover changes associated with the development of tall shrublands. |
| first_indexed | 2024-03-12T15:59:39Z |
| format | Article |
| id | doaj.art-7503f76b80354b7090ac594a14596aa5 |
| institution | Directory Open Access Journal |
| issn | 1748-9326 |
| language | English |
| last_indexed | 2024-03-12T15:59:39Z |
| publishDate | 2014-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | Environmental Research Letters |
| spelling | doaj.art-7503f76b80354b7090ac594a14596aa52023-08-09T14:42:48ZengIOP PublishingEnvironmental Research Letters1748-93262014-01-019202500410.1088/1748-9326/9/2/025004Regional and landscape-scale variability of Landsat-observed vegetation dynamics in northwest Siberian tundraGerald V Frost0Howard E Epstein1Donald A Walker2Department of Environmental Sciences, University of Virginia , PO Box 400123, Charlottesville, VA 22903, USADepartment of Environmental Sciences, University of Virginia , PO Box 400123, Charlottesville, VA 22903, USAAlaska Geobotany Center, University of Alaska , PO Box 757000, Fairbanks, AK 99775, USAWidespread increases in Arctic tundra productivity have been documented for decades using coarse-scale satellite observations, but finer-scale observations indicate that changes have been very uneven, with a high degree of landscape- and regional-scale heterogeneity. Here we analyze time-series of the Normalized Difference Vegetation Index (NDVI) observed by Landsat (1984–2012), to assess landscape- and regional-scale variability of tundra vegetation dynamics in the northwest Siberian Low Arctic, a little-studied region with varied soils, landscape histories, and permafrost attributes. We also estimate spatio-temporal rates of land-cover change associated with expansion of tall alder ( Alnus ) shrublands, by integrating Landsat time-series with very-high-resolution imagery dating to the mid-1960s. We compiled Landsat time-series for eleven widely-distributed landscapes, and performed linear regression of NDVI values on a per-pixel basis. We found positive net NDVI trends (‘greening’) in nine of eleven landscapes. Net greening occurred in alder shrublands in all landscapes, and strong greening tended to correspond to shrublands that developed since the 1960s. Much of the spatial variability of greening within landscapes was linked to landscape physiography and permafrost attributes, while between-landscape variability largely corresponded to differences in surficial geology. We conclude that continued increases in tundra productivity in the region are likely in upland tundra landscapes with fine-textured, cryoturbated soils; these areas currently tend to support discontinuous vegetation cover, but are highly susceptible to rapid increases in vegetation cover, as well as land-cover changes associated with the development of tall shrublands.https://doi.org/10.1088/1748-9326/9/2/025004tundravegetation dynamicsLandsatnormalized difference vegetation index (NDVI)shrub expansionpermafrost |
| spellingShingle | Gerald V Frost Howard E Epstein Donald A Walker Regional and landscape-scale variability of Landsat-observed vegetation dynamics in northwest Siberian tundra Environmental Research Letters tundra vegetation dynamics Landsat normalized difference vegetation index (NDVI) shrub expansion permafrost |
| title | Regional and landscape-scale variability of Landsat-observed vegetation dynamics in northwest Siberian tundra |
| title_full | Regional and landscape-scale variability of Landsat-observed vegetation dynamics in northwest Siberian tundra |
| title_fullStr | Regional and landscape-scale variability of Landsat-observed vegetation dynamics in northwest Siberian tundra |
| title_full_unstemmed | Regional and landscape-scale variability of Landsat-observed vegetation dynamics in northwest Siberian tundra |
| title_short | Regional and landscape-scale variability of Landsat-observed vegetation dynamics in northwest Siberian tundra |
| title_sort | regional and landscape scale variability of landsat observed vegetation dynamics in northwest siberian tundra |
| topic | tundra vegetation dynamics Landsat normalized difference vegetation index (NDVI) shrub expansion permafrost |
| url | https://doi.org/10.1088/1748-9326/9/2/025004 |
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