Observed long-term greening of alpine vegetation—a case study in the French Alps
We combined imagery from multiple sources (MODIS, Landsat-5, 7, 8) with land cover data to test for long-term (1984–2015) greening or browning trends of vegetation in a temperate alpine area, the Ecrins National Park, in the context of recent climate change and domestic grazing practices. We showed...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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IOP Publishing
2017-01-01
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| Series: | Environmental Research Letters |
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| Online Access: | https://doi.org/10.1088/1748-9326/aa84bd |
| _version_ | 1797748147513982976 |
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| author | Bradley Z Carlson Monica C Corona Cédric Dentant Richard Bonet Wilfried Thuiller Philippe Choler |
| author_facet | Bradley Z Carlson Monica C Corona Cédric Dentant Richard Bonet Wilfried Thuiller Philippe Choler |
| author_sort | Bradley Z Carlson |
| collection | DOAJ |
| description | We combined imagery from multiple sources (MODIS, Landsat-5, 7, 8) with land cover data to test for long-term (1984–2015) greening or browning trends of vegetation in a temperate alpine area, the Ecrins National Park, in the context of recent climate change and domestic grazing practices. We showed that over half (56%) of the Ecrins National Park displayed significant increases in peak normalized difference vegetation index (NDVI _max ) over the last 16 years (2000–2015). Importantly, the highest proportional increases in NDVI _max occurred in rocky habitats at high elevations (> 2500 m a.s.l.). While spatial agreement in the direction of change in NDVI _max as detected by MODIS and Landsat was high (76% overlap), correlations between log-response ratio values were of moderate strength (approx. 0.3). In the context of above treeline habitats, we found that proportional increases in NDVI _max were higher between 1984 and 2000 than between 2000 and 2015, suggesting a slowing of greening dynamics during the recent decade. The timing of accelerated greening prior to 2000 coincided with a pronounced increase in the amount of snow-free growing degree-days that occurred during the 1980s and 1990s. In the case of grasslands and low-shrub habitats, we did not find evidence for a negative effect of grazing on greening trends, possibly due to the low grazing intensity typically found in the study area. We propose that the emergence of a longer and warmer growing season enabled high-elevation plant communities to produce more biomass, and also allowed for plant colonization of habitats previously characterized by long-lasting snow cover. Increasing plant productivity in an alpine context has potential implications for biodiversity trajectories and for ecosystem services in mountain landscapes. The presented evidence for long-term greening trends in a representative region of the European Alps provides the basis for further research on mechanisms of greening in alpine landscapes. |
| first_indexed | 2024-03-12T16:01:45Z |
| format | Article |
| id | doaj.art-89112ee44d4a49af83af2d20c536dee7 |
| institution | Directory Open Access Journal |
| issn | 1748-9326 |
| language | English |
| last_indexed | 2024-03-12T16:01:45Z |
| publishDate | 2017-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | Environmental Research Letters |
| spelling | doaj.art-89112ee44d4a49af83af2d20c536dee72023-08-09T14:37:12ZengIOP PublishingEnvironmental Research Letters1748-93262017-01-01121111400610.1088/1748-9326/aa84bdObserved long-term greening of alpine vegetation—a case study in the French AlpsBradley Z Carlson0Monica C Corona1Cédric Dentant2Richard Bonet3Wilfried Thuiller4Philippe Choler5Univ. Grenoble Alpes CNRS, LECA , F-38000 Grenoble, France; LTER ‘Zone Atelier Alpes’ , F-38000 Grenoble, France; Author to whom any correspondence should be addressed.Univ. Grenoble Alpes CNRS, LECA , F-38000 Grenoble, France; LTER ‘Zone Atelier Alpes’ , F-38000 Grenoble, FranceParc National des Ecrins , Domaine de Charance, F-05000 Gap, FranceParc National des Ecrins , Domaine de Charance, F-05000 Gap, FranceUniv. Grenoble Alpes CNRS, LECA , F-38000 Grenoble, France; LTER ‘Zone Atelier Alpes’ , F-38000 Grenoble, FranceUniv. Grenoble Alpes CNRS, LECA , F-38000 Grenoble, France; LTER ‘Zone Atelier Alpes’ , F-38000 Grenoble, FranceWe combined imagery from multiple sources (MODIS, Landsat-5, 7, 8) with land cover data to test for long-term (1984–2015) greening or browning trends of vegetation in a temperate alpine area, the Ecrins National Park, in the context of recent climate change and domestic grazing practices. We showed that over half (56%) of the Ecrins National Park displayed significant increases in peak normalized difference vegetation index (NDVI _max ) over the last 16 years (2000–2015). Importantly, the highest proportional increases in NDVI _max occurred in rocky habitats at high elevations (> 2500 m a.s.l.). While spatial agreement in the direction of change in NDVI _max as detected by MODIS and Landsat was high (76% overlap), correlations between log-response ratio values were of moderate strength (approx. 0.3). In the context of above treeline habitats, we found that proportional increases in NDVI _max were higher between 1984 and 2000 than between 2000 and 2015, suggesting a slowing of greening dynamics during the recent decade. The timing of accelerated greening prior to 2000 coincided with a pronounced increase in the amount of snow-free growing degree-days that occurred during the 1980s and 1990s. In the case of grasslands and low-shrub habitats, we did not find evidence for a negative effect of grazing on greening trends, possibly due to the low grazing intensity typically found in the study area. We propose that the emergence of a longer and warmer growing season enabled high-elevation plant communities to produce more biomass, and also allowed for plant colonization of habitats previously characterized by long-lasting snow cover. Increasing plant productivity in an alpine context has potential implications for biodiversity trajectories and for ecosystem services in mountain landscapes. The presented evidence for long-term greening trends in a representative region of the European Alps provides the basis for further research on mechanisms of greening in alpine landscapes.https://doi.org/10.1088/1748-9326/aa84bdNDVIMODISLandsatpeak productivityclimate changetemperate mountains |
| spellingShingle | Bradley Z Carlson Monica C Corona Cédric Dentant Richard Bonet Wilfried Thuiller Philippe Choler Observed long-term greening of alpine vegetation—a case study in the French Alps Environmental Research Letters NDVI MODIS Landsat peak productivity climate change temperate mountains |
| title | Observed long-term greening of alpine vegetation—a case study in the French Alps |
| title_full | Observed long-term greening of alpine vegetation—a case study in the French Alps |
| title_fullStr | Observed long-term greening of alpine vegetation—a case study in the French Alps |
| title_full_unstemmed | Observed long-term greening of alpine vegetation—a case study in the French Alps |
| title_short | Observed long-term greening of alpine vegetation—a case study in the French Alps |
| title_sort | observed long term greening of alpine vegetation a case study in the french alps |
| topic | NDVI MODIS Landsat peak productivity climate change temperate mountains |
| url | https://doi.org/10.1088/1748-9326/aa84bd |
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