Publications by authors named "Juha M Alatalo"

31 Publications

A new method for broad-scale modeling and projection of plant assemblages under climatic, biotic, and environmental cofiltering.

Conserv Biol 2021 Jun 15. Epub 2021 Jun 15.

Environmental Science Center, Qatar University, Doha, P.O. Box 2713, Qatar.

There is increasing interest in broad-scale analysis, modeling, and prediction of the distribution and composition of plant species assemblages under climatic, environmental, and biotic filtering, particularly for conservation purposes. We devised a method (broad-scale analysis & modeling of plant assemblages under climatic-biotic-environmental co-filtering, BAM-PACC) for reliably predicting the impact of climate change on arbitrarily large assemblages of plant communities, while also considering competing biotic and abiotic factors. When applied to a large set of plant communities in the Swiss Alps, BAM-PACC explained presences/absences of 175 plant species in 608 plots with >87% cross-validated accuracy, predicted decreases in α, β, and γ diversity by 2040 under both moderate and extreme climate scenarios, and identified plant species likely to be favored/disfavored by climate change. BAM-PACC also revealed the importance of topography and soil in determining the distribution of plant species and their response to climate change, and showed the overriding importance of temperature extremes rather than averages. BAM-PACC was able to address a number of challenging research problems, such as scaling to large numbers of species, exploiting species relationships, dealing with species rarity, and overwhelming proportion of absences in the presence/absence matrix. By handling hundreds/thousands of plants and plots simultaneously over large areas, BAM-PACC can help broad-scale conservation of plant species under climate change, as it allows species that require urgent conservation planning and policies (assisted migration, seed conservation, ex-situ conservation) to be detected and prioritized. BAM-PACC can also increase the practicality of assisted colonization of plant species, by helping to prevent ill-advised introduction of plant species with limited future survival probability in a certain area. This article is protected by copyright. All rights reserved.
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http://dx.doi.org/10.1111/cobi.13797DOI Listing
June 2021

Experimental warming differentially affects vegetative and reproductive phenology of tundra plants.

Nat Commun 2021 06 11;12(1):3442. Epub 2021 Jun 11.

Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, USA.

Rapid climate warming is altering Arctic and alpine tundra ecosystem structure and function, including shifts in plant phenology. While the advancement of green up and flowering are well-documented, it remains unclear whether all phenophases, particularly those later in the season, will shift in unison or respond divergently to warming. Here, we present the largest synthesis to our knowledge of experimental warming effects on tundra plant phenology from the International Tundra Experiment. We examine the effect of warming on a suite of season-wide plant phenophases. Results challenge the expectation that all phenophases will advance in unison to warming. Instead, we find that experimental warming caused: (1) larger phenological shifts in reproductive versus vegetative phenophases and (2) advanced reproductive phenophases and green up but delayed leaf senescence which translated to a lengthening of the growing season by approximately 3%. Patterns were consistent across sites, plant species and over time. The advancement of reproductive seasons and lengthening of growing seasons may have significant consequences for trophic interactions and ecosystem function across the tundra.
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http://dx.doi.org/10.1038/s41467-021-23841-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8196023PMC
June 2021

Spatio-temporal variation in potential habitats for rare and endangered plants and habitat conservation based on the maximum entropy model.

Sci Total Environ 2021 Aug 19;784:147080. Epub 2021 Apr 19.

Center for Integrative Conservation, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla 666303, Yunnan, China; University of Chinese Academy of Sciences, Beijing 100049, China.

Rare and endangered plants (REPs) act as key indicators for species habitat priorities, and can thus be critical in global biodiversity protection work. Human activities and climate change pose great threats to REPs, so protection should be a top priority. In this study, we used the maximum entropy model (Maxent) to identify current and future (2050) potential habitats of REPs in the Xishuangbanna tropical area of China. We compared potential habitats with existing protected areas (PAs) in gap analysis, and used a transfer matrix to quantify changes in potential habitats. By comparing the potential distribution obtained with existing land use and land cover, we analyzed the impact of human-dominated land use changes on potential habitats of REPs and identified the main habitat patch types of REPs. The results showed that the current potential habitat area of hotspots is 2989.85 km, which will be reduced to 247.93 km by 2050, accounting for 15.60% and 1.29% of the total research area, respectively. Analysis of land use and land cover showed that rubber plantation was the human-dominated land use posing the greatest threat to potential habitats of REPs, occupying 23.40% and 21.62% of current and future potential habitats, respectively. Monsoon evergreen broad-leaved forest was identified as the main habitat patch type for REPs in Xishuangbanna and occupied the highest proportion of potential habitat area. Gap analysis showed that only 35.85% of habitat hotspots are currently included in existing PAs and that this will decrease to 32.26% by 2050. This emphasizes the importance of protecting current and future potential habitats of REPs in a dynamic conservation approach that can adapt to changes in future climate and human activities.
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http://dx.doi.org/10.1016/j.scitotenv.2021.147080DOI Listing
August 2021

Effects of ambient climate and three warming treatments on fruit production in an alpine, subarctic meadow community.

Am J Bot 2021 03;108(3):411-422

Department of Plant and Environmental Sciences, University of Gothenburg, P.O. Box 461, SE-405 30, Gothenburg, Sweden.

Premise: Climate change is having major impacts on alpine and arctic regions, and inter-annual variations in temperature are likely to increase. How increased climate variability will impact plant reproduction is unclear.

Methods: In a 4-year study on fruit production by an alpine plant community in northern Sweden, we applied three warming regimes: (1) a static level of warming with open-top chambers (OTC), (2) press warming, a yearly stepwise increase in warming, and (3) pulse warming, a single-year pulse event of higher warming. We analyzed the relationship between fruit production and monthly temperatures during the budding period, fruiting period, and whole fruit production period and the effect of winter and summer precipitation on fruit production.

Results: Year and treatment had a significant effect on total fruit production by evergreen shrubs, Cassiope tetragona, and Dryas octopetala, with large variations between treatments and years. Year, but not treatment, had a significant effect on deciduous shrubs and graminoids, both of which increased fruit production over the 4 years, while forbs were negatively affected by the press warming, but not by year. Fruit production was influenced by ambient temperature during the previous-year budding period, current-year fruiting period, and whole fruit production period. Minimum and average temperatures were more important than maximum temperature. In general, fruit production was negatively correlated with increased precipitation.

Conclusions: These results indicate that predicted increased climate variability and increased precipitation due to climate change may affect plant reproductive output and long-term community dynamics in alpine meadow communities.
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http://dx.doi.org/10.1002/ajb2.1631DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8251864PMC
March 2021

Temperature and pH define the realised niche space of arbuscular mycorrhizal fungi.

New Phytol 2021 07 4;231(2):763-776. Epub 2021 Mar 4.

CIRAD, UPR Forêts et Sociétés, Yamoussoukro, Côte d'Ivoire.

The arbuscular mycorrhizal (AM) fungi are a globally distributed group of soil organisms that play critical roles in ecosystem function. However, the ecological niches of individual AM fungal taxa are poorly understood. We collected > 300 soil samples from natural ecosystems worldwide and modelled the realised niches of AM fungal virtual taxa (VT; approximately species-level phylogroups). We found that environmental and spatial variables jointly explained VT distribution worldwide, with temperature and pH being the most important abiotic drivers, and spatial effects generally occurring at local to regional scales. While dispersal limitation could explain some variation in VT distribution, VT relative abundance was almost exclusively driven by environmental variables. Several environmental and spatial effects on VT distribution and relative abundance were correlated with phylogeny, indicating that closely related VT exhibit similar niche optima and widths. Major clades within the Glomeraceae exhibited distinct niche optima, Acaulosporaceae generally had niche optima in low pH and low temperature conditions, and Gigasporaceae generally had niche optima in high precipitation conditions. Identification of the realised niche space occupied by individual and phylogenetic groups of soil microbial taxa provides a basis for building detailed hypotheses about how soil communities respond to gradients and manipulation in ecosystems worldwide.
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http://dx.doi.org/10.1111/nph.17240DOI Listing
July 2021

Bryophyte cover and richness decline after 18 years of experimental warming in alpine Sweden.

AoB Plants 2020 Dec 24;12(6):plaa061. Epub 2020 Nov 24.

Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden.

Climate change is expected to affect alpine and Arctic tundra communities. Most previous long-term studies have focused on impacts on vascular plants, this study examined impacts of long-term warming on bryophyte communities. Experimental warming with open-top chambers (OTCs) was applied for 18 years to a mesic meadow and a dry heath alpine plant community. Species abundance was measured in 1995, 1999, 2001 and 2013. Species composition changed significantly from original communities in the heath, but remained similar in mesic meadow. Experimental warming increased beta diversity in the heath. Bryophyte cover and species richness both declined with long-term warming, while Simpson diversity showed no significant responses. Over the 18-year period, bryophyte cover in warmed plots decreased from 43 % to 11 % in heath and from 68 % to 35 % in meadow (75 % and 48 % decline, respectively, in original cover), while richness declined by 39 % and 26 %, respectively. Importantly, the decline in cover and richness first emerged after 7 years. Warming caused significant increase in litter in both plant communities. Deciduous shrub and litter cover had negative impact on bryophyte cover. We show that bryophyte species do not respond similarly to climate change. Total bryophyte cover declined in both heath and mesic meadow under experimental long-term warming (by 1.5-3 °C), driven by general declines in many species. Principal response curve, cover and richness results suggested that bryophytes in alpine heath are more susceptible to warming than in meadow, supporting the suggestion that bryophytes may be less resistant in drier environments than in wetter habitats. Species loss was slower than the decline in bryophyte abundance, and diversity remained similar in both communities. Increased deciduous shrub and litter cover led to decline in bryophyte cover. The non-linear response to warming over time underlines the importance of long-term experiments and monitoring.
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http://dx.doi.org/10.1093/aobpla/plaa061DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7759949PMC
December 2020

Temporal variations in ambient air quality indicators in Shanghai municipality, China.

Sci Rep 2020 07 9;10(1):11350. Epub 2020 Jul 9.

Changjiang Water Resources Protection Institute, Wuhan, 430051, China.

Official data on daily PM, PM, SO, NO, CO, and maximum 8-h average O (O_8h) concentrations from January 2015 to December 2018 were evaluated and air pollution status and dynamics in Shanghai municipality were examined. Factors affecting air quality, including meteorological factors and socio-economic indicators, were analyzed. The main findings were that: (1) Overall air quality status in Shanghai municipality has improved and number of days meeting 'Chinese ambient air quality standards' (CAAQS) Grade II has increased. (2) The most frequent major pollutant in Shanghai municipality is O (which exceeded the standard on 110 days in 2015, 84 days in 2016, 126 days in 2017, 113 days in 2018), followed by PM (120days in 2015, 104 days in 2016, 67 days in 2017, 61 days in 2018) and NO (50 days in 2015, 67 days in 2016, 79 days in 2017, 63 days in 2018). (3) PM pollution in winter and O pollution in summer are the main air quality challenges in Shanghai municipality. (4) Statistical analysis suggested that PM, PM, SO and NO concentrations were significantly negatively associated with precipitation (Prec) and atmosphere temperature (T) (p < 0.05), while the O concentration was significantly positively associated with Prec and T (p < 0.05). Lower accumulation of PM, SO, NO, and CO and more serious O pollution were revealed during months with higher temperature and more precipitation in Shanghai. The correlation between the socio-economic factors and the air pollutants suggest that further rigorous measures are needed to control PM and that further studies are needed to identify O formation mechanisms and control strategies. The results provide scientific insights into meteorological factors and socio-economic indicators influencing air pollution in Shanghai.
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http://dx.doi.org/10.1038/s41598-020-68201-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7347849PMC
July 2020

Quantifying variations in ecosystem services in altitude-associated vegetation types in a tropical region of China.

Sci Total Environ 2020 Jul 13;726:138565. Epub 2020 Apr 13.

State Key Laboratory of Hydrology Water Resource and Hydraulic Engineering, Hohai University, Nanjing, 210098, China.

Natural vegetation is important for ecosystem services (ESs) provision, but is decreasing rapidly due to human-driven land use change, especially rapid expansion of commercial plantations. This is leading to a decrease in ESs provision, so measures are urgently needed to protect natural vegetation. Human activities, especially commercial plantations, can also lead to differences in vegetation types and associated ESs provision. This feature varies with altitude, an issue which has received insufficient attention. In this study, four ESs relevant to stakeholders (carbon storage, nitrogen export, sediment retention and water yield) were assessed. InVEST models and statistical methods (ANOVA; exploratory hierarchical clustering) were used to analyse: 1) similarities/differences in ESs provision between different vegetation types and 2) spatial differences in ESs in different altitude zones in the Xishuangbanna region of China. The results showed that vegetation types in Xishuangbanna and their ESs supply capacity differed markedly, with the overall ESs supply capacity of natural forests exceeding that of commercial plantations. Promotion of mixed organic agriculture can be a balanced measure to secure future economic development and ecological protection. This study can act as reference for vegetation protection in other areas within and beyond China.
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http://dx.doi.org/10.1016/j.scitotenv.2020.138565DOI Listing
July 2020

Decomposition rate and stabilization across six tundra vegetation types exposed to >20 years of warming.

Sci Total Environ 2020 Jul 30;724:138304. Epub 2020 Mar 30.

Department of Biological and Environmental Sciences, College of Arts and Sciences, Qatar University, P.O. Box 2713, Doha, Qatar; Environmental Science Center, Qatar University, P.O. Box: 2713, Doha, Qatar.

Aims: Litter decomposition is an important driver of soil carbon and nutrient cycling in nutrient-limited Arctic ecosystems. However, climate change is expected to induce changes that directly or indirectly affect decomposition. We examined the direct effects of long-term warming relative to differences in soil abiotic properties associated with vegetation type on litter decomposition across six subarctic vegetation types.

Methods: In six vegetation types, rooibos and green tea bags were buried for 70-75 days at 8 cm depth inside warmed (by open-top chambers) and control plots that had been in place for 20-25 years. Standardized initial decomposition rate and stabilization of the labile material fraction of tea (into less decomposable material) were calculated from tea mass losses. Soil moisture and temperature were measured bi-weekly during summer and plant-available nutrients were measured with resin probes.

Results: Initial decomposition rate was decreased by the warming treatment. Stabilization was less affected by warming and determined by vegetation type and soil moisture. Soil metal concentrations impeded both initial decomposition rate and stabilization.

Conclusions: While a warmer Arctic climate will likely have direct effects on initial litter decomposition rates in tundra, stabilization of organic matter was more affected by vegetation type and soil parameters and less prone to be affected by direct effects of warming.
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http://dx.doi.org/10.1016/j.scitotenv.2020.138304DOI Listing
July 2020

SoilTemp: A global database of near-surface temperature.

Glob Chang Biol 2020 Nov 24;26(11):6616-6629. Epub 2020 Jun 24.

A.N. Severtsov Institute of Ecology and Evolution, Russian Academy of Sciences, Moscow, Russia.

Current analyses and predictions of spatially explicit patterns and processes in ecology most often rely on climate data interpolated from standardized weather stations. This interpolated climate data represents long-term average thermal conditions at coarse spatial resolutions only. Hence, many climate-forcing factors that operate at fine spatiotemporal resolutions are overlooked. This is particularly important in relation to effects of observation height (e.g. vegetation, snow and soil characteristics) and in habitats varying in their exposure to radiation, moisture and wind (e.g. topography, radiative forcing or cold-air pooling). Since organisms living close to the ground relate more strongly to these microclimatic conditions than to free-air temperatures, microclimatic ground and near-surface data are needed to provide realistic forecasts of the fate of such organisms under anthropogenic climate change, as well as of the functioning of the ecosystems they live in. To fill this critical gap, we highlight a call for temperature time series submissions to SoilTemp, a geospatial database initiative compiling soil and near-surface temperature data from all over the world. Currently, this database contains time series from 7,538 temperature sensors from 51 countries across all key biomes. The database will pave the way toward an improved global understanding of microclimate and bridge the gap between the available climate data and the climate at fine spatiotemporal resolutions relevant to most organisms and ecosystem processes.
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http://dx.doi.org/10.1111/gcb.15123DOI Listing
November 2020

Scale effects on the relationships between land characteristics and ecosystem services- a case study in Taihu Lake Basin, China.

Sci Total Environ 2020 May 1;716:137083. Epub 2020 Feb 1.

Changjiang Water Resources Protection Institute, Wuhan 430051, China. Electronic address:

It is generally recognized that marginal changes in landscape characteristics can influence multiple ecosystem services, but the causal relationships involved are still very unclear due to lack of knowledge and data gaps. Planners and managers need spatial information and evidence on these causal relationships for systematic and sound land planning. This study evaluated the effects of landscape characteristics on seven types of ecosystem services and the trade-offs among the ecosystem services by combining statistical data and the InVEST model with correlation analysis across Taihu Lake Basin, China. We found that all ecosystem services except food production increased from 2005 to 2015 in the whole basin. We also found that correlations between landscape characteristic metrics and ecosystem services indicators changed over time for different types of ecosystem service indicators at the county scale, and between county and pixel scale. The results demonstrated the effects of landscape characteristic metrics on multiple ecosystem services indicators and the tradeoffs among these ecosystem services indicators, and also revealed scale effects on correlations and tradeoffs. Therefore planners and managers need to consider both landscape characteristic metrics and scale effects for effective landscape management to improve ecosystem services and reduce unwanted tradeoffs.
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http://dx.doi.org/10.1016/j.scitotenv.2020.137083DOI Listing
May 2020

Global change effects on plant communities are magnified by time and the number of global change factors imposed.

Proc Natl Acad Sci U S A 2019 09 19;116(36):17867-17873. Epub 2019 Aug 19.

Systems Ecology, Department of Ecological Science, Vrije Universiteit, 1081 HV Amsterdam, The Netherlands.

Global change drivers (GCDs) are expected to alter community structure and consequently, the services that ecosystems provide. Yet, few experimental investigations have examined effects of GCDs on plant community structure across multiple ecosystem types, and those that do exist present conflicting patterns. In an unprecedented global synthesis of over 100 experiments that manipulated factors linked to GCDs, we show that herbaceous plant community responses depend on experimental manipulation length and number of factors manipulated. We found that plant communities are fairly resistant to experimentally manipulated GCDs in the short term (<10 y). In contrast, long-term (≥10 y) experiments show increasing community divergence of treatments from control conditions. Surprisingly, these community responses occurred with similar frequency across the GCD types manipulated in our database. However, community responses were more common when 3 or more GCDs were simultaneously manipulated, suggesting the emergence of additive or synergistic effects of multiple drivers, particularly over long time periods. In half of the cases, GCD manipulations caused a difference in community composition without a corresponding species richness difference, indicating that species reordering or replacement is an important mechanism of community responses to GCDs and should be given greater consideration when examining consequences of GCDs for the biodiversity-ecosystem function relationship. Human activities are currently driving unparalleled global changes worldwide. Our analyses provide the most comprehensive evidence to date that these human activities may have widespread impacts on plant community composition globally, which will increase in frequency over time and be greater in areas where communities face multiple GCDs simultaneously.
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http://dx.doi.org/10.1073/pnas.1819027116DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6731679PMC
September 2019

Quantifying ecosystem services supply and demand shortfalls and mismatches for management optimisation.

Sci Total Environ 2019 Feb 10;650(Pt 1):1426-1439. Epub 2018 Sep 10.

Department of Biological and Environmental Sciences, College of Arts and Sciences, Qatar University, P.O. Box 2713, Doha, Qatar.

Research on ecosystem services (ESs) has increased substantially in recent decades, but the findings have been slow to affect actual management, perhaps because most studies to date have neglected ESs supply and demand coupling mechanisms. Human reliance on ESs is due to the capacity of the landscape to supply services, but also to a societal need for these services. Sustainable land management requires supply and demand mismatches to be reconciled and the needs of different stakeholders to be balanced. Explicit spatial mapping of ESs supply and demand associated with land use changes can provide relevant insights for enhancing land management in urban areas. The emphasis is now shifting to enhancing sustainable land use, to ensure that supply meets or exceeds demand. In this study, a comprehensive framework comprising four core steps for quantifying ESs supply and demand changes associated with land use changes was developed and applied in a case study on Shanghai municipality, on the basis of environmental quality standards and policy goals. The balance thresholds of ESs supply and demand were derived by regression analysis between ESs and land use/land cover types. The results revealed large spatial heterogeneity in supply and demand for four key ESs tested: carbon sequestration, water retention, particulate (PM) removal and recreation. Carbon sequestration, water retention and recreation services all showed major shortfalls in supply that changed dramatically with urban land use change. This is valuable empirical evidence and has timely policy implications for management in a rapid urbanising world.
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http://dx.doi.org/10.1016/j.scitotenv.2018.09.126DOI Listing
February 2019

Plant functional trait change across a warming tundra biome.

Nature 2018 10 26;562(7725):57-62. Epub 2018 Sep 26.

Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden.

The tundra is warming more rapidly than any other biome on Earth, and the potential ramifications are far-reaching because of global feedback effects between vegetation and climate. A better understanding of how environmental factors shape plant structure and function is crucial for predicting the consequences of environmental change for ecosystem functioning. Here we explore the biome-wide relationships between temperature, moisture and seven key plant functional traits both across space and over three decades of warming at 117 tundra locations. Spatial temperature-trait relationships were generally strong but soil moisture had a marked influence on the strength and direction of these relationships, highlighting the potentially important influence of changes in water availability on future trait shifts in tundra plant communities. Community height increased with warming across all sites over the past three decades, but other traits lagged far behind predicted rates of change. Our findings highlight the challenge of using space-for-time substitution to predict the functional consequences of future warming and suggest that functions that are tied closely to plant height will experience the most rapid change. They also reveal the strength with which environmental factors shape biotic communities at the coldest extremes of the planet and will help to improve projections of functional changes in tundra ecosystems with climate warming.
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http://dx.doi.org/10.1038/s41586-018-0563-7DOI Listing
October 2018

Asynchrony among local communities stabilises ecosystem function of metacommunities.

Ecol Lett 2017 Dec 24;20(12):1534-1545. Epub 2017 Oct 24.

Department of Geobotany, Moscow State Lomonosov University, Leninskie gory 1-12, 119234, Moscow, Russia.

Temporal stability of ecosystem functioning increases the predictability and reliability of ecosystem services, and understanding the drivers of stability across spatial scales is important for land management and policy decisions. We used species-level abundance data from 62 plant communities across five continents to assess mechanisms of temporal stability across spatial scales. We assessed how asynchrony (i.e. different units responding dissimilarly through time) of species and local communities stabilised metacommunity ecosystem function. Asynchrony of species increased stability of local communities, and asynchrony among local communities enhanced metacommunity stability by a wide range of magnitudes (1-315%); this range was positively correlated with the size of the metacommunity. Additionally, asynchronous responses among local communities were linked with species' populations fluctuating asynchronously across space, perhaps stemming from physical and/or competitive differences among local communities. Accordingly, we suggest spatial heterogeneity should be a major focus for maintaining the stability of ecosystem services at larger spatial scales.
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http://dx.doi.org/10.1111/ele.12861DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6849522PMC
December 2017

Responses of lichen communities to 18 years of natural and experimental warming.

Ann Bot 2017 07;120(1):159-170

Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 461, SE-405?30 Gothenburg, Sweden.

Background And Aims: Climate change is expected to have major impacts on high alpine and arctic ecosystems in the future, but empirical data on the impact of long-term warming on lichen diversity and richness are sparse. This study report the effects of 18 years of ambient and experimental warming on lichens and vascular plant cover in two alpine plant communities, a dry heath with sparse canopy cover (54 %) and a mesic meadow with a more developed (67 %) canopy cover, in sub-arctic Sweden.

Methods: The effects of long-term passive experimental warming using open top chambers (OTCs) on lichens and total vascular plant cover, and the impact of plant cover on lichen community parameters, were analysed.

Key Results: Between 1993 and 2013, mean annual temperature increased about 2 °C. Both site and experimental warming had a significant effect on cover, species richness, effective number of species evenness of lichens, and total plant canopy cover. Lichen cover increased in the heath under ambient conditions, and remained more stable under experimental warming. The negative effect on species richness and effective number of species was driven by a decrease in lichens under experimental warming in the meadow. Lichen cover, species richness, effective number of species evenness were negatively correlated with plant canopy cover. There was a significant negative impact on one species and a non-significant tendency of lower abundance of the most common species in response to experimental warming.

Conclusions: The results from the long-term warming study imply that arctic and high alpine lichen communities are likely to be negatively affected by climate change and an increase in plant canopy cover. Both biotic and abiotic factors are thus important for future impacts of climate change on lichens.
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http://dx.doi.org/10.1093/aob/mcx053DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5737088PMC
July 2017

Community and species-specific responses of plant traits to 23 years of experimental warming across subarctic tundra plant communities.

Sci Rep 2017 05 31;7(1):2571. Epub 2017 May 31.

Department of Biological and Environmental Sciences, College of Arts and Sciences, Qatar University, P.O. Box 2713, Doha, Qatar.

To improve understanding of how global warming may affect competitive interactions among plants, information on the responses of plant functional traits across species to long-term warming is needed. Here we report the effect of 23 years of experimental warming on plant traits across four different alpine subarctic plant communities: tussock tundra, Dryas heath, dry heath and wet meadow. Open-top chambers (OTCs) were used to passively warm the vegetation by 1.5-3 °C. Changes in leaf width, leaf length and plant height of 22 vascular plant species were measured. Long-term warming significantly affected all plant traits. Overall, plant species were taller, with longer and wider leaves, compared with control plots, indicating an increase in biomass in warmed plots, with 13 species having significant increases in at least one trait and only three species having negative responses. The response varied among species and plant community in which the species was sampled, indicating community-warming interactions. Thus, plant trait responses are both species- and community-specific. Importantly, we show that there is likely to be great variation between plant species in their ability to maintain positive growth responses over the longer term, which might cause shifts in their relative competitive ability.
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http://dx.doi.org/10.1038/s41598-017-02595-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5451416PMC
May 2017

Impacts of twenty years of experimental warming on soil carbon, nitrogen, moisture and soil mites across alpine/subarctic tundra communities.

Sci Rep 2017 03 15;7:44489. Epub 2017 Mar 15.

Institute of Biology and Ecology, Faculty of Science, P. J. Šafárik University in Košice, Šrobárova 2, 041 54 Košice, Slovakia.

High-altitude and alpine areas are predicted to experience rapid and substantial increases in future temperature, which may have serious impacts on soil carbon, nutrient and soil fauna. Here we report the impact of 20 years of experimental warming on soil properties and soil mites in three contrasting plant communities in alpine/subarctic Sweden. Long-term warming decreased juvenile oribatid mite density, but had no effect on adult oribatids density, total mite density, any major mite group or the most common species. Long-term warming also caused loss of nitrogen, carbon and moisture from the mineral soil layer in mesic meadow, but not in wet meadow or heath or from the organic soil layer. There was a significant site effect on the density of one mite species, Oppiella neerlandica, and all soil parameters. A significant plot-scale impact on mites suggests that small-scale heterogeneity may be important for buffering mites from global warming. The results indicated that juvenile mites may be more vulnerable to global warming than adult stages. Importantly, the results also indicated that global warming may cause carbon and nitrogen losses in alpine and tundra mineral soils and that its effects may differ at local scale.
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http://dx.doi.org/10.1038/srep44489DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5353735PMC
March 2017

Climate change will seriously impact bird species dwelling above the treeline: A prospective study for the Italian Alps.

Sci Total Environ 2017 Jul 9;590-591:686-694. Epub 2017 Mar 9.

BirdLife International - Lipu (Lega Italiana Protezione Uccelli), Conservation Department, Via Udine 3/a, I-43122 Parma, Italy.

High mountain systems are predicted to be especially vulnerable to the impact of climate change, with the climatically-constrained tree limit rapidly shifted upslope. In turn, the impact of upward treeline migration on mountain-dwelling bird species is expected to significantly reduce habitat suitability. We developed the first projection of the expected climate-driven rise of the whole treeline (19,256km) of the Italian Alps. The study area extends over 20,700km, ranging over 550km in longitude and 320km in latitude. We then investigated how much the expected treeline rise will induce a) shrinking and shifting of the elevation range and b) loss in suitable habitat for the flagship species rock ptarmigan, an alpine bird species dwelling above the treeline and, similarly to many other alpine species, highly vulnerable to treeline rise. We also investigated the potential gain in suitable habitat for rock ptarmigan due to the climate-driven upshift in the uppermost thermal limit. At lower altitudes (1500-1600m a.s.l.), the average expected upshift in the current treeline resulted in 195, 274 and 354m over the short (2010-2039), medium (2040-2069) and long term (2070-2099) respectively. Above 2400m a.s.l., it was less than 30m even in the long term. Overall, during the three climate periods the extent of suitable habitat for rock ptarmigan above the current treeline is projected to decrease by 28.12%, 38.43% and 49.11% respectively. In contrast, the expected gain in suitable habitat due to the shift in the uppermost thermal limit will be severely restrained by the limited surface extension in the top portion of the Italian Alps. The presented approach can promote similar studies elsewhere in the globe, providing a regional perspective to the projection of climate change impact on bird species dwelling above the treeline.
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http://dx.doi.org/10.1016/j.scitotenv.2017.03.027DOI Listing
July 2017

Braking effect of climate and topography on global change-induced upslope forest expansion.

Int J Biometeorol 2017 Mar 19;61(3):541-548. Epub 2016 Aug 19.

Via G. Saragat 4, 43123, Parma, Italy.

Forests are expected to expand into alpine areas due to global climate change. It has recently been shown that temperature alone cannot realistically explain this process and that upslope tree advance in a warmer scenario may depend on the availability of sites with adequate geomorphic/topographic characteristics. Here, we show that, besides topography (slope and aspect), climate itself can produce a braking effect on the upslope advance of subalpine forests and that tree limit is influenced by non-linear and non-monotonic contributions of the climate variables which act upon treeline upslope advance with varying relative strengths. Our results suggest that global climate change impact on the upslope advance of subalpine forests should be interpreted in a more complex way where climate can both speed up and slow down the process depending on complex patterns of contribution from each climate and non-climate variable.
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http://dx.doi.org/10.1007/s00484-016-1231-yDOI Listing
March 2017

Planning for assisted colonization of plants in a warming world.

Sci Rep 2016 06 27;6:28542. Epub 2016 Jun 27.

Department of Earth and Environmental Sciences, University of Pavia, via S. Epifanio 14, I-27100 Pavia, Italy.

Assisted colonization is one way of facilitating range shifts for species that are restricted in their ability to move in response to climate change. Here we conceptualize and apply a new decision framework for modelling assisted colonization of plant species prior to in situ realization. Three questions were examined: a) Is species translocation useful in a certain area? b) where, and c) how long will it be successful in the future? Applying our framework to Carex foetida in Italy at the core of its distribution and its southern edge revealed that assisted colonization could be successful in short-term (2010-2039) climate conditions, partially in medium (2040-2069) but not in long-term (2070-2099) scenarios. We show that, for some species, it is likely that assisted colonization would be successful in some portions of the recipient site under current and short-term climate conditions, but over the mid- and long-term, climate changes will make species translocation unsuccessful. The proposed decision framework can help identify species that will need different conservation actions (seed banks and/or botanical gardens) when assisted colonization is unlikely to be successful. Furthermore it has broad applicability, as it can support planning of assisted migration in mountainous areas in the face of climate change.
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http://dx.doi.org/10.1038/srep28542DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4921867PMC
June 2016

Impacts of different climate change regimes and extreme climatic events on an alpine meadow community.

Sci Rep 2016 Feb 18;6:21720. Epub 2016 Feb 18.

Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 461, SE-405 30 Gothenburg, Sweden.

Climate variability is expected to increase in future but there exist very few experimental studies that apply different warming regimes on plant communities over several years. We studied an alpine meadow community under three warming regimes over three years. Treatments consisted of (a) a constant level of warming with open-top chambers (ca. 1.9 °C above ambient), (b) yearly stepwise increases in warming (increases of ca. 1.0, 1.9 and 3.5 °C), and (c) pulse warming, a single first-year pulse event of warming (increase of ca. 3.5 °C). Pulse warming and stepwise warming was hypothesised to cause distinct first-year and third-year effects, respectively. We found support for both hypotheses; however, the responses varied among measurement levels (whole community, canopy, bottom layer, and plant functional groups), treatments, and time. Our study revealed complex responses of the alpine plant community to the different experimentally imposed climate warming regimes. Plant cover, height and biomass frequently responded distinctly to the constant level of warming, the stepwise increase in warming and the extreme pulse-warming event. Notably, we found that stepwise warming had an accumulating effect on biomass, the responses to the different warming regimes varied among functional groups, and the short-term perturbations had negative effect on species richness and diversity.
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http://dx.doi.org/10.1038/srep21720DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4757884PMC
February 2016

Collembola at three alpine subarctic sites resistant to twenty years of experimental warming.

Sci Rep 2015 Dec 16;5:18161. Epub 2015 Dec 16.

Biology Centre, Institute of Soil Biology, Academy of Science of the Czech Republic, 370 05 České Budějovice, Czech Republic.

This study examined the effects of micro-scale, site and 19 and 21 years of experimental warming on Collembola in three contrasting alpine subarctic plant communities (poor heath, rich meadow, wet meadow). Unexpectedly, experimental long-term warming had no significant effect on species richness, effective number of species, total abundance or abundance of any Collembola species. There were micro-scale effects on species richness, total abundance, and abundance of 10 of 35 species identified. Site had significant effect on effective number of species, and abundance of six species, with abundance patterns differing between sites. Site and long-term warming gave non-significant trends in species richness. The highest species richness was observed in poor heath, but mean species richness tended to be highest in rich meadow and lowest in wet meadow. Warming showed a tendency for a negative impact on species richness. This long-term warming experiment across three contrasting sites revealed that Collembola is capable of high resistance to climate change. We demonstrated that micro-scale and site effects are the main controlling factors for Collembola abundance in high alpine subarctic environments. Thus local heterogeneity is likely important for soil fauna composition and may play a crucial role in buffering Collembola against future climate change.
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http://dx.doi.org/10.1038/srep18161DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4680968PMC
December 2015

Impacts of urbanization on the distribution of heavy metals in soils along the Huangpu River, the drinking water source for Shanghai.

Environ Sci Pollut Res Int 2016 Mar 12;23(6):5222-31. Epub 2015 Nov 12.

Department of Biological and Environmental Sciences, College of Arts and Sciences, Qatar University, P.O. Box 2713, Doha, Qatar.

We investigated the horizontal and vertical distribution of heavy metals (Hg, Pb, Zn, Cu, Cd, As, Ni, and Cr) in soils in the water source protection zone for Shanghai to study the origins of these metals, their connections with urbanization, and their potential risk posed on the ecosystem. Determination of metal concentrations in 50 topsoil samples and nine soil profiles indicated that Hg, Pb, Zn, and Cu were present in significantly higher concentrations in topsoil than in deep soil layers. The spatial distributions of Hg, Pb, Zn, and Cu and contamination hotspots for these metals in the study area were similar to those near heavy industries and urban built-up areas. Emissions from automobiles resulted in increased soil concentrations of Cu, Pb, and Zn along roadsides, while high concentrations of Hg in the soil resulted from recent atmospheric deposition. Calculation of the potential ecological risk indicated that the integrative risk of these heavy metals in most areas was low, but a few sites surrounding high density of factories showed moderate risks.
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http://dx.doi.org/10.1007/s11356-015-5745-3DOI Listing
March 2016

Vascular plant abundance and diversity in an alpine heath under observed and simulated global change.

Sci Rep 2015 May 7;5:10197. Epub 2015 May 7.

Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 461, 405 30 Gothenburg, Sweden.

Global change is predicted to cause shifts in species distributions and biodiversity in arctic tundra. We applied factorial warming and nutrient manipulation to a nutrient and species poor alpine/arctic heath community for seven years. Vascular plant abundance in control plots increased by 31%. There were also notable changes in cover in the nutrient and combined nutrient and warming treatments, with deciduous and evergreen shrubs declining, grasses overgrowing these plots. Sedge abundance initially increased significantly with nutrient amendment and then declined, going below initial values in the combined nutrient and warming treatment. Nutrient addition resulted in a change in dominance hierarchy from deciduous shrubs to grasses. We found significant declines in vascular plant diversity and evenness in the warming treatment and a decline in diversity in the combined warming and nutrient addition treatment, while nutrient addition caused a decline in species richness. The results give some experimental support that species poor plant communities with low diversity may be more vulnerable to loss of species diversity than communities with higher initial diversity. The projected increase in nutrient deposition and warming may therefore have negative impacts on ecosystem processes, functioning and services due to loss of species diversity in an already impoverished environment.
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http://dx.doi.org/10.1038/srep10197DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4423496PMC
May 2015

Effects of human trampling on abundance and diversity of vascular plants, bryophytes and lichens in alpine heath vegetation, Northern Sweden.

Springerplus 2015 26;4:95. Epub 2015 Feb 26.

Department of Ecology and Genetics, Uppsala University, Campus Gotland, SE-621 67 Visby, Sweden.

This study investigated the effects of human trampling on cover, diversity and species richness in an alpine heath ecosystem in northern Sweden. We tested the hypothesis that proximity to trails decreases plant cover, diversity and species richness of the canopy and the understory. We found a significant decrease in plant cover with proximity to the trail for the understory, but not for the canopy level, and significant decreases in the abundance of deciduous shrubs in the canopy layer and lichens in the understory. Proximity also had a significant negative impact on species richness of lichens. However, there were no significant changes in species richness, diversity or evenness of distribution in the canopy or understory with proximity to the trail. While not significant, liverworts, acrocarpous and pleurocarpous bryophytes tended to have contrasting abundance patterns with differing proximity to the trail, indicating that trampling may cause shifts in dominance hierarchies of different groups of bryophytes. Due to the decrease in understory cover, the abundance of litter, rock and soil increased with proximity to the trail. These results demonstrate that low-frequency human trampling in alpine heaths over long periods can have major negative impacts on lichen abundance and species richness. To our knowledge, this is the first study to demonstrate that trampling can decrease species richness of lichens. It emphasises the importance of including species-level data on non-vascular plants when conducting studies in alpine or tundra ecosystems, since they often make up the majority of species and play a significant role in ecosystem functioning and response in many of these extreme environments.
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http://dx.doi.org/10.1186/s40064-015-0876-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4353821PMC
March 2015

Dominance hierarchies, diversity and species richness of vascular plants in an alpine meadow: contrasting short and medium term responses to simulated global change.

PeerJ 2014 22;2:e406. Epub 2014 May 22.

Department of Biological and Environmental Sciences, University of Gothenburg , Gothenburg , Sweden.

We studied the impact of simulated global change on a high alpine meadow plant community. Specifically, we examined whether short-term (5 years) responses are good predictors for medium-term (7 years) changes in the system by applying a factorial warming and nutrient manipulation to 20 plots in Latnjajaure, subarctic Sweden. Seven years of experimental warming and nutrient enhancement caused dramatic shifts in dominance hierarchies in response to the nutrient and the combined warming and nutrient enhancement treatments. Dominance hierarchies in the meadow moved from a community being dominated by cushion plants, deciduous, and evergreen shrubs to a community being dominated by grasses, sedges, and forbs. Short-term responses were shown to be inconsistent in their ability to predict medium-term responses for most functional groups, however, grasses showed a consistent and very substantial increase in response to nutrient addition over the seven years. The non-linear responses over time point out the importance of longer-term studies with repeated measurements to be able to better predict future changes. Forecasted changes to temperature and nutrient availability have implications for trophic interactions, and may ultimately influence the access to and palatability of the forage for grazers. Depending on what anthropogenic change will be most pronounced in the future (increase in nutrient deposits, warming, or a combination of them both), different shifts in community dominance hierarchies may occur. Generally, this study supports the productivity-diversity relationship found across arctic habitats, with community diversity peaking in mid-productivity systems and degrading as nutrient availability increases further. This is likely due the increasing competition in plant-plant interactions and the shifting dominance structure with grasses taking over the experimental plots, suggesting that global change could have high costs to biodiversity in the Arctic.
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http://dx.doi.org/10.7717/peerj.406DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4034599PMC
June 2014

Simulated global change: contrasting short and medium term growth and reproductive responses of a common alpine/Arctic cushion plant to experimental warming and nutrient enhancement.

Springerplus 2014 22;3:157. Epub 2014 Mar 22.

Department of Ecology and Genetics, Uppsala University, Campus Gotland, SE-621 67 Visby, Sweden.

Cushion plants are important components of alpine and Arctic plant communities around the world. They fulfill important roles as facilitators, nurse plants and foundation species across trophic levels for vascular plants, arthropods and soil microorganisms, the importance of these functions increasing with the relative severity of the environment. Here we report results from one of the few experimental studies simulating global change impacts on cushion plants; a factorial experiment with warming and nutrient enhancement that was applied to an alpine population of the common nurse plant, Silene acaulis, in sub-arctic Sweden. Experimental perturbations had significant short-term impacts on both stem elongation and leaf length. S. acaulis responded quickly by increasing stem elongation and (to a lesser extent) leaf length in the warming, nutrient, and the combined warming and nutrient enhancements. Cover and biomass also initially increased in response to the perturbations. However, after the initial positive short-term responses, S. acaulis cover declined in the manipulations, with the nutrient and combined warming and nutrient treatments having largest negative impact. No clear patterns were found for fruit production. Our results show that S. acaulis living in harsh environments has potential to react quickly when experiencing years with favorable conditions, and is more responsive to nutrient enhancement than to warming in terms of vegetative growth. While these conditions have an initial positive impact, populations experiencing longer-term increased nutrient levels will likely be negatively affected.
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http://dx.doi.org/10.1186/2193-1801-3-157DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4000594PMC
May 2014

Plant community responses to 5 years of simulated climate change in meadow and heath ecosystems at a subarctic-alpine site.

Oecologia 2009 Sep 25;161(3):601-10. Epub 2009 Jun 25.

Department of Plant and Environmental Sciences, Göteborg University, P.O. Box 461, 40530 Göteborg, Sweden.

Climate change was simulated by increasing temperature and nutrient availability in an alpine landscape. We conducted a field experiment of BACI-design (before/after control/impact) running for five seasons in two alpine communities (heath and meadow) with the factors temperature (increase of ca. 1.5-3.0 degrees C) and nutrients (5 g N, 5 g P per m(2)) in a fully factorial design in northern Swedish Lapland. The response variables were abundances of plant species and functional types. Plant community responses to the experimental perturbations were investigated, and the responses of plant functional types were examined in comparison to responses at the species level. Nutrient addition, exclusively and in combination with enhanced temperature increase, exerted the most pronounced responses at the species-specific and community levels. The main responses to nutrient addition were increases in graminoids and forbs, whereas deciduous shrubs, evergreen shrubs, bryophytes, and lichens decreased. The two plant communities of heath or meadow showed different vegetation responses to the environmental treatments despite the fact that both communities were located on the same subarctic-alpine site. Furthermore, we showed that the abundance of forbs increased in response to the combined treatment of temperature and nutrient addition in the meadow plant community. Within a single-plant functional type, most species responded similarly to the enhanced treatments although there were exceptions, particularly in the moss and lichen functional types. Plant community structure showed BACI responses in that vegetation dominance relationships in the existing plant functional types changed to varying degrees in all plots, including control plots. Betula nana and lichens increased in the temperature-increased enhancements and in control plots in the heath plant community during the treatment period. The increases in control plots were probably a response to the observed warming during the treatment period in the region.
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http://dx.doi.org/10.1007/s00442-009-1392-zDOI Listing
September 2009

Plant community responses to experimental warming across the tundra biome.

Proc Natl Acad Sci U S A 2006 Jan 20;103(5):1342-6. Epub 2006 Jan 20.

Boreal Ecology Cooperative Research Unit, U.S. Department of Agriculture Forest Service Pacific Northwest Research Station, University of Alaska, P.O. Box 756780, Fairbanks, AK 99775-6780, USA.

Recent observations of changes in some tundra ecosystems appear to be responses to a warming climate. Several experimental studies have shown that tundra plants and ecosystems can respond strongly to environmental change, including warming; however, most studies were limited to a single location and were of short duration and based on a variety of experimental designs. In addition, comparisons among studies are difficult because a variety of techniques have been used to achieve experimental warming and different measurements have been used to assess responses. We used metaanalysis on plant community measurements from standardized warming experiments at 11 locations across the tundra biome involved in the International Tundra Experiment. The passive warming treatment increased plant-level air temperature by 1-3 degrees C, which is in the range of predicted and observed warming for tundra regions. Responses were rapid and detected in whole plant communities after only two growing seasons. Overall, warming increased height and cover of deciduous shrubs and graminoids, decreased cover of mosses and lichens, and decreased species diversity and evenness. These results predict that warming will cause a decline in biodiversity across a wide variety of tundra, at least in the short term. They also provide rigorous experimental evidence that recently observed increases in shrub cover in many tundra regions are in response to climate warming. These changes have important implications for processes and interactions within tundra ecosystems and between tundra and the atmosphere.
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http://dx.doi.org/10.1073/pnas.0503198103DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1360515PMC
January 2006
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