Warming, Sheep and Volcanoes: Land Cover Changes in Iceland Evident in Satellite NDVI Trends

Raynolds, Martha K.; Magnússon, Borgþór; Metúsalemsson, Sigmar; Magnússon, Sigurður H.

doi:10.3390/rs70809492

Cited by 21 publications

(16 citation statements)

References 31 publications

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“…Climate warming in recent decades has generally extended LOS by the combined responses of SOS and EOS (Jeong, Ho, Gim, & Brown, ; Linderholm, ), with the largest extensions at high northern latitudes (Gonsamo & Chen, ; Raynolds, Magnusson, Metusalemsson, & Magnusson, ; Zhao et al., ) and high altitudes (Zhao et al., ) where temperatures are rising fastest (IPCC, ). This warming‐induced extension of LOS at high northern latitudes has primarily been driven by an advance in SOS, while EOS has generally been less responsive to temperature (Cleland et al., ; Menzel et al., ; Zhao et al., ).…”

Section: Introductionmentioning

confidence: 99%

Phenological responses of Icelandic subarctic grasslands to short‐term and long‐term natural soil warming

Leblans

Sigurðsson

Vicca

et al. 2017

Global Change Biology

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The phenology of vegetation, particularly the length of the growing season (LOS; i.e., the period from greenup to senescence), is highly sensitive to climate change, which could imply potent feedbacks to the climate system, for example, by altering the ecosystem carbon (C) balance. In recent decades, the largest extensions of LOS have been reported at high northern latitudes, but further warming-induced LOS extensions may be constrained by too short photoperiod or unfulfilled chilling requirements. Here, we studied subarctic grasslands, which cover a vast area and contain large C stocks, but for which LOS changes under further warming are highly uncertain. We measured LOS extensions of Icelandic subarctic grasslands along natural geothermal soil warming gradients of different age (short term, where the measurements started after 5 years of warming and long term, i.e., warmed since ≥50 years) using ground-level measurements of normalized difference vegetation index. We found that LOS linearly extended with on average 2.1 days per °C soil warming up to the highest soil warming levels (ca. +10°C) and that LOS had the potential to extend at least 1 month. This indicates that the warming impact on LOS in these subarctic grasslands will likely not saturate in the near future. A similar response to short- and long-term warming indicated a strong physiological control of the phenological response of the subarctic grasslands to warming and suggested that genetic adaptations and community changes were likely of minor importance. We conclude that the warming-driven extension of the LOSs of these subarctic grasslands did not saturate up to +10°C warming, and hence that growing seasons of high-latitude grasslands are likely to continue lengthening with future warming (unless genetic adaptations or species shifts do occur). This persistence of the warming-induced extension of LOS has important implications for the C-sink potential of subarctic grasslands under climate change.

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Section: Introductionmentioning

confidence: 99%

Phenological responses of Icelandic subarctic grasslands to short‐term and long‐term natural soil warming

Leblans

Sigurðsson

Vicca

et al. 2017

Global Change Biology

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“…The contribution of different water sources varies longitudinally from the glacier terminus to downstream reaches and temporally with glacier shrinkage (Brittain & Milner, 2001; Milner, Brown & Hannah, 2009; Gao et al, 2016), resulting in distinct hydrology and physicochemical features which control the ecological structures and processes in glacier-fed streams (Brown, Hannah & Milner, 2003, 2007; Sertic Peric et al, 2015). Synchronizing with the hydrological changes in glacier-fed streams, vegetation growth and aboveground biomass in the catchment also has a clear elevation gradient (Carlyle, Fraser & Turkington, 2014) which will likely be amplified due to climate warming (Zhang et al, 2013; Raynolds et al, 2015). The changed landcover modifies terrestrial and aquatic biogeochemistry (Sadro, Nelson & Melack, 2012), and affects stream biofilms (Figueiredo et al, 2010; Nielsen et al, 2012).…”

Section: Discussionmentioning

confidence: 99%

“…As a prominent component of the glacier forefront, glacier-fed streams have a highly heterogeneous environment due to longitudinal alterations of landcover, river hydrology and morphology, sediment transport, and biogeochemical processes (Hood & Scott, 2008; Laghari, 2013; Hotaling, Hood & Hamilton, 2017; Milner et al, 2017). For example, from glacier terminus to downstream, terrestrial vegetation increases (Zhang et al, 2013; Raynolds et al, 2015), stream channel lengthens (Milner, Brown & Hannah, 2009; Robinson, Thompson & Freestone, 2014), and water source compositions changes (Brown, Hannah & Milner, 2003).…”

Section: Introductionmentioning

confidence: 99%

Ecological networks reveal contrasting patterns of bacterial and fungal communities in glacier-fed streams in Central Asia

Ren

Gao

2019

PeerJ

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Bacterial and fungal communities in biofilms are important components in driving biogeochemical processes in stream ecosystems. Previous studies have well documented the patterns of bacterial alpha diversity in stream biofilms in glacier-fed streams, where, however, beta diversity of the microbial communities has received much less attention especially considering both bacterial and fungal communities. A focus on beta diversity can provide insights into the mechanisms driving community changes associated to large environmental fluctuations and disturbances, such as in glacier-fed streams. Moreover, modularity of co-occurrence networks can reveal more ecological and evolutionary properties of microbial communities beyond taxonomic groups. Here, integrating beta diversity and co-occurrence approach, we explored the network topology and modularity of the bacterial and fungal communities with consideration of environmental variation in glacier-fed streams in Central Asia. Combining results from hydrological modeling and normalized difference of vegetation index, this study highlighted that hydrological variables and vegetation status are major variables determining the environmental heterogeneity of glacier-fed streams. Bacterial communities formed a more complex and connected network, while the fungal communities formed a more clustered network. Moreover, the strong interrelations among the taxonomic dissimilarities of bacterial community (BC) and modules suggest they had common processes in driving diversity and taxonomic compositions across the heterogeneous environment. In contrast, fungal community (FC) and modules generally showed distinct driving processes to each other. Moreover, bacterial and fungal communities also had different driving processes. Furthermore, the variation of BC and modules were strongly correlated with hydrological properties and vegetation status but not with nutrients, while FC and modules (except one module) were not associated with environmental variation. Our results suggest that bacterial and fungal communities had distinct mechanisms in structuring microbial networks, and environmental variation had strong influences on bacterial communities but not on fungal communities. The fungal communities have unique assembly mechanisms and physiological properties which might lead to their insensitive responses to environmental variations compared to bacterial communities. Overall, beyond alpha diversity in previous studies, these results add our knowledge that bacterial and fungal communities have contrasting assembly mechanisms and respond differently to environmental variation in glacier-fed streams.

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“…Because of the close relationship between vegetation phenology and the terrestrial ecosystem [1][2][3], vegetation is commonly used to determine the ecological response to environmental changes [4][5][6][7], such as climate change [8][9][10][11], land cover and land use change [12][13][14][15][16][17][18][19], drought [20,21], and changes in net primary productivity [22]. Satellite remote sensing vegetation indices offer opportunities to monitor vegetation phenology and environmental changes in a repeatable manner [22].…”

Section: Introductionmentioning

confidence: 99%

Exploring Long Term Spatial Vegetation Trends in Taiwan from AVHRR NDVI3g Dataset Using RDA and HCA Analyses

2016

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Due to 4000 m elevation variation with temperature differences equivalent to 50 degrees of latitudinal gradient, exploring Taiwan's spatial vegetation trends is valuable in terms of diverse ecosystems and climatic types covering a relatively small island with an area of 36,000 km 2 . This study analyzed Taiwan's spatial vegetation trends with controlling environmental variables through redundancy (RDA) and hierarchical cluster (HCA) analyses over three decades of monthly normalized difference vegetation index (NDVI) derived from the Advanced Very High Resolution Radiometer (AVHRR) NDVI3g data for 19 selected weather stations over the island. Results showed two spatially distinct vegetation response groups. Group 1 comprises weather stations which remained relatively natural showing a slight increasing NDVI tendency accompanied with rising temperature, whereas Group 2 comprises stations with high level of human development showing a slight decreasing NDVI tendency associated with increasing temperature-induced moisture stress. Statistically significant controlling variables include climatic factors (temperature and precipitation), orographic factors (mean slope and aspects), and anthropogenic factor (population density). Given the potential trajectories for future warming, variable precipitation, and population pressure, challenges, such as land-cover and water-induced vegetation stress, need to be considered simultaneously for establishing adequate adaptation strategies to combat climate change challenges in Taiwan.

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Warming, Sheep and Volcanoes: Land Cover Changes in Iceland Evident in Satellite NDVI Trends

Cited by 21 publications

References 31 publications

Phenological responses of Icelandic subarctic grasslands to short‐term and long‐term natural soil warming

Phenological responses of Icelandic subarctic grasslands to short‐term and long‐term natural soil warming

Ecological networks reveal contrasting patterns of bacterial and fungal communities in glacier-fed streams in Central Asia

Exploring Long Term Spatial Vegetation Trends in Taiwan from AVHRR NDVI3g Dataset Using RDA and HCA Analyses

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