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Climate variability rather than overstocking causes recent large scale cover changes of Tibetan pastures.

Lehnert LW, Wesche K, Trachte K, Reudenbach C, Bendix J - Sci Rep (2016)

Bottom Line: This supply function is claimed to be threatened by pasture degradation on the TP and the associated loss of water regulation functions.However, neither potential large scale degradation changes nor their drivers are known.Increasing livestock numbers as a result of land use changes exacerbated the negative trends but were not their exclusive driver.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Geography, Philipps-University of Marburg, Deutschhausstr. 10, 35037 Marburg, Germany.

ABSTRACT
The Tibetan Plateau (TP) is a globally important "water tower" that provides water for nearly 40% of the world's population. This supply function is claimed to be threatened by pasture degradation on the TP and the associated loss of water regulation functions. However, neither potential large scale degradation changes nor their drivers are known. Here, we analyse trends in a high-resolution dataset of grassland cover to determine the interactions among vegetation dynamics, climate change and human impacts on the TP. The results reveal that vegetation changes have regionally different triggers: While the vegetation cover has increased since the year 2000 in the north-eastern part of the TP due to an increase in precipitation, it has declined in the central and western parts of the TP due to rising air temperature and declining precipitation. Increasing livestock numbers as a result of land use changes exacerbated the negative trends but were not their exclusive driver. Thus, we conclude that climate variability instead of overgrazing has been the primary cause for large scale vegetation cover changes on the TP since the new millennium. Since areas of positive and negative changes are almost equal in extent, pasture degradation is not generally proceeding.

No MeSH data available.


Related in: MedlinePlus

Map of the TP (a) and changes in livestock numbers (LN) in the TAR and Qinghai in sheep equivalents (relative to year 1952, b). The map shows all of the locations mentioned in the text. The map has been created in R statistical software40 based on elevation data, political boundaries, lakes and rivers from41. The grey area in (b) is the investigated time period during which the satellite data, and thus the area-wide plant cover product, were available.
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f1: Map of the TP (a) and changes in livestock numbers (LN) in the TAR and Qinghai in sheep equivalents (relative to year 1952, b). The map shows all of the locations mentioned in the text. The map has been created in R statistical software40 based on elevation data, political boundaries, lakes and rivers from41. The grey area in (b) is the investigated time period during which the satellite data, and thus the area-wide plant cover product, were available.

Mentions: The major part of the TP belongs administratively to two different provinces, Qinghai in the north-eastern part and the Tibetan Autonomous Region (TAR) covering the southern and western part (see Fig. 1a for a location map). Since regional politics and social structures are considerably different, it is worthwhile to separately analyse LN in both provinces to find out if they evolved differently during the last decades. In the TAR, LN increased dramatically between 2000 and 2006, while LN in the adjacent Qinghai Province decreased considerably during the 1990s and have remained almost constant since 2000 (Fig. 1b). In the TAR, where data for all prefectures are available, LN increased at the beginning of the new millennium in prefectures Ngari and Qamdo, whereas the increase occurred later in Nagqu, Lhasa and Nyingtri (Fig. 2). Only Shigatze and Shannan were not exposed to increasing LN since 2000.


Climate variability rather than overstocking causes recent large scale cover changes of Tibetan pastures.

Lehnert LW, Wesche K, Trachte K, Reudenbach C, Bendix J - Sci Rep (2016)

Map of the TP (a) and changes in livestock numbers (LN) in the TAR and Qinghai in sheep equivalents (relative to year 1952, b). The map shows all of the locations mentioned in the text. The map has been created in R statistical software40 based on elevation data, political boundaries, lakes and rivers from41. The grey area in (b) is the investigated time period during which the satellite data, and thus the area-wide plant cover product, were available.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4829870&req=5

f1: Map of the TP (a) and changes in livestock numbers (LN) in the TAR and Qinghai in sheep equivalents (relative to year 1952, b). The map shows all of the locations mentioned in the text. The map has been created in R statistical software40 based on elevation data, political boundaries, lakes and rivers from41. The grey area in (b) is the investigated time period during which the satellite data, and thus the area-wide plant cover product, were available.
Mentions: The major part of the TP belongs administratively to two different provinces, Qinghai in the north-eastern part and the Tibetan Autonomous Region (TAR) covering the southern and western part (see Fig. 1a for a location map). Since regional politics and social structures are considerably different, it is worthwhile to separately analyse LN in both provinces to find out if they evolved differently during the last decades. In the TAR, LN increased dramatically between 2000 and 2006, while LN in the adjacent Qinghai Province decreased considerably during the 1990s and have remained almost constant since 2000 (Fig. 1b). In the TAR, where data for all prefectures are available, LN increased at the beginning of the new millennium in prefectures Ngari and Qamdo, whereas the increase occurred later in Nagqu, Lhasa and Nyingtri (Fig. 2). Only Shigatze and Shannan were not exposed to increasing LN since 2000.

Bottom Line: This supply function is claimed to be threatened by pasture degradation on the TP and the associated loss of water regulation functions.However, neither potential large scale degradation changes nor their drivers are known.Increasing livestock numbers as a result of land use changes exacerbated the negative trends but were not their exclusive driver.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Geography, Philipps-University of Marburg, Deutschhausstr. 10, 35037 Marburg, Germany.

ABSTRACT
The Tibetan Plateau (TP) is a globally important "water tower" that provides water for nearly 40% of the world's population. This supply function is claimed to be threatened by pasture degradation on the TP and the associated loss of water regulation functions. However, neither potential large scale degradation changes nor their drivers are known. Here, we analyse trends in a high-resolution dataset of grassland cover to determine the interactions among vegetation dynamics, climate change and human impacts on the TP. The results reveal that vegetation changes have regionally different triggers: While the vegetation cover has increased since the year 2000 in the north-eastern part of the TP due to an increase in precipitation, it has declined in the central and western parts of the TP due to rising air temperature and declining precipitation. Increasing livestock numbers as a result of land use changes exacerbated the negative trends but were not their exclusive driver. Thus, we conclude that climate variability instead of overgrazing has been the primary cause for large scale vegetation cover changes on the TP since the new millennium. Since areas of positive and negative changes are almost equal in extent, pasture degradation is not generally proceeding.

No MeSH data available.


Related in: MedlinePlus