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Gargiulo S, Boscutti F, Carrer M, Prendin AL, Unterholzner L, Dibona R, Casolo V. Snowpack permanence shapes the growth and dynamic of non-structural carbohydrates in Juniperus communis in alpine tundra. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 948:174891. [PMID: 39047817 DOI: 10.1016/j.scitotenv.2024.174891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2024] [Revised: 07/17/2024] [Accepted: 07/17/2024] [Indexed: 07/27/2024]
Abstract
Climate warming is altering snowpack permanence in alpine tundra, modifying shrub growth and distribution. Plant acclimation to snowpack changes depends on the capability to guarantee growth and carbon storage, suggesting that the content of non-structural carbohydrates (NSC) in plant organs can be a key trait to depict the plant response under different snow regimes. To test this hypothesis, we designed a 3-years long manipulative experiment aimed at evaluating the effect of snow melt timing (i.e., early, control, and late) on NSC content in needles, bark and wood of Juniperus communis L. growing at high elevation in the Alps. Starch evidenced a general decrease from late spring to summer in control and early melting, while starch was low but stable in plants subjected to a late snow melt. Leaves, bark and wood have different level of soluble NSC changing during growing season: in bark, sugars content decreased significantly in late summer, while there was no seasonal effect in needles and wood. Soluble NSC and starch were differently related with the plant growth, when considering different tissues and snow treatment. In leaf and bark we observed a starch depletion in control and early melting plants, consistently to a higher growth (i.e., twig elongation), while in late snow melt, we did not find any significant relationship between growth and NSC concentration. Our findings confirmed that snowpack duration affects the onset of the growing season promoting a change in carbon allocation in plant organs and, between bark and wood in twigs. Finally, our results suggest that plants, at this elevation, could take advantage from an early snow melt caused by climate warming, most likely due to photosynthetic activity by maintaining the level of reserves and enhancing the carbon investment for growth.
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Affiliation(s)
- Sara Gargiulo
- Department of Agricultural Food Environmental Animal Sciences, University of Udine, Udine, Italy; Department of Life Sciences, University of Trieste, Trieste, Italy.
| | - Francesco Boscutti
- Department of Agricultural Food Environmental Animal Sciences, University of Udine, Udine, Italy; NBFC, National Biodiversity Future Center, 90133 Palermo, Italy
| | - Marco Carrer
- Department of Land, Environment, Agriculture and Forestry, University of Padua, Italy
| | - Angela Luisa Prendin
- Department of Land, Environment, Agriculture and Forestry, University of Padua, Italy; Section for Ecoinformatics and Biodiversity, Department of Biology, Aarhus University, Aarhus, Denmark
| | - Lucrezia Unterholzner
- Department of Land, Environment, Agriculture and Forestry, University of Padua, Italy
| | - Raffaela Dibona
- Department of Land, Environment, Agriculture and Forestry, University of Padua, Italy
| | - Valentino Casolo
- Department of Agricultural Food Environmental Animal Sciences, University of Udine, Udine, Italy
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Enhanced habitat loss of the Himalayan endemic flora driven by warming-forced upslope tree expansion. Nat Ecol Evol 2022; 6:890-899. [PMID: 35654898 DOI: 10.1038/s41559-022-01774-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2021] [Accepted: 04/22/2022] [Indexed: 11/08/2022]
Abstract
High-elevation trees cannot always reach the thermal treeline, the potential upper range limit set by growing-season temperature. But delineation of the realized upper range limit of trees and quantification of the drivers, which lead to trees being absent from the treeline, is lacking. Here, we used 30 m resolution satellite tree-cover data, validated by more than 0.7 million visual interpretations from Google Earth images, to map the realized range limit of trees along the Himalaya which harbours one of the world's richest alpine endemic flora. The realized range limit of trees is ~800 m higher in the eastern Himalaya than in the western and central Himalaya. Trees had reached their thermal treeline positions in more than 80% of the cases over eastern Himalaya but are absent from the treeline position in western and central Himalaya, due to anthropogenic disturbance and/or premonsoon drought. By combining projections of the deviation of trees from the treeline position due to regional environmental stresses with warming-induced treeline shift, we predict that trees will migrate upslope by ~140 m by the end of the twenty-first century in the eastern Himalaya. This shift will cause the endemic flora to lose at least ~20% of its current habitats, highlighting the necessity to reassess the effectiveness of current conservation networks and policies over the Himalaya.
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Unterholzner L, Prendin AL, Dibona R, Menardi R, Casolo V, Gargiulo S, Boscutti F, Carrer M. Transient Effects of Snow Cover Duration on Primary Growth and Leaf Traits in a Tundra Shrub. FRONTIERS IN PLANT SCIENCE 2022; 13:822901. [PMID: 35481143 PMCID: PMC9037292 DOI: 10.3389/fpls.2022.822901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Accepted: 02/14/2022] [Indexed: 06/14/2023]
Abstract
With the recent climate warming, tundra ecotones are facing a progressive acceleration of spring snowpack melting and extension of the growing season, with evident consequences to vegetation. Along with summer temperature, winter precipitation has been recently recognised as a crucial factor for tundra shrub growth and physiology. However, gaps of knowledge still exist on long-living plant responses to different snowpack duration, especially on how intra-specific and year-to-year variability together with multiple functional trait adjustments could influence the long-term responses. To fill this gap, we conducted a 3 years snow manipulation experiment above the Alpine treeline on the typical tundra species Juniperus communis, the conifer with the widest distributional range in the north emisphere. We tested shoot elongation, leaf area, stomatal density, leaf dry weight and leaf non-structural carbohydrate content of plants subjected to anticipated, natural and postponed snowpack duration. Anticipated snowpack melting enhanced new shoot elongation and increased stomatal density. However, plants under prolonged snow cover seemed to compensate for the shorter growing period, likely increasing carbon allocation to growth. In fact, these latter showed larger needles and low starch content at the beginning of the growing season. Variability between treatments slightly decreased over time, suggesting a progressive acclimation of juniper to new conditions. In the context of future warming scenarios, our results support the hypothesis of shrub biomass increase within the tundra biome. Yet, the picture is still far from being complete and further research should focus on transient and fading effects of changing conditions in the long term.
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Affiliation(s)
- Lucrezia Unterholzner
- Department of Land Environment Agriculture and Forestry, University of Padova, Legnaro, Italy
| | - Angela Luisa Prendin
- Department of Land Environment Agriculture and Forestry, University of Padova, Legnaro, Italy
- Department of Biology, Ecoinformatics and Biodiversity, Aarhus University, Aarhus, Denmark
| | - Raffaella Dibona
- Department of Land Environment Agriculture and Forestry, University of Padova, Legnaro, Italy
| | - Roberto Menardi
- Department of Land Environment Agriculture and Forestry, University of Padova, Legnaro, Italy
| | - Valentino Casolo
- Department of Agricultural Food Environmental Animal Sciences, University of Udine, Udine, Italy
| | - Sara Gargiulo
- Department of Agricultural Food Environmental Animal Sciences, University of Udine, Udine, Italy
- Department of Life Sciences, University of Trieste, Trieste, Italy
| | - Francesco Boscutti
- Department of Agricultural Food Environmental Animal Sciences, University of Udine, Udine, Italy
| | - Marco Carrer
- Department of Land Environment Agriculture and Forestry, University of Padova, Legnaro, Italy
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Jupa R, Mészáros M, Hoch G, Plavcová L. Trunk radial growth, water and carbon relations of mature apple trees on two size-controlling rootstocks during severe summer drought. TREE PHYSIOLOGY 2022; 42:289-303. [PMID: 34409459 DOI: 10.1093/treephys/tpab111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 08/09/2021] [Indexed: 06/13/2023]
Abstract
The use of size-controlling rootstocks is central to modern high-density fruit production systems. While biological mechanisms responsible for vigor control are not fully understood, differences in water relations and carbohydrate storage ability have been suggested as two potential factors. To better understand the processes that control growth vigor, we analyzed the trunk radial variation at seasonal and diurnal timescales and measured the midday leaf water potential (ΨMD), leaf gas exchange and concentrations of non-structural carbohydrates (NSC) in apple trees of variety 'Jonagold' grafted on two rootstocks of contrasting growth vigor (dwarfing J-TE-G vs invigorating J-TE-H). The measurements were conducted during an exceptionally hot and dry summer. We found that smaller annual trunk radial increments in dwarfed trees were primarily due to an earlier cessation of trunk secondary growth. The interdiurnal trunk circumference changes (ΔC) were slightly lower in dwarfed trees, and these trees also had fewer days with positive ΔC values, particularly during the driest summer months. The trunks of dwarfed trees shrank gradually during the drought, showed less pronounced diurnal variation of trunk circumference and the maximum trunk daily shrinkage was only weakly responsive to the vapor pressure deficit. These results indicated that lower turgidity in the cambial region may have limited the trunk radial expansion in dwarfed trees during the hot and dry days. Dwarfed trees also maintained lower ΨMD and leaf gas exchange rates during the summer drought. These parameters decreased in parallel for both rootstock combinations, suggesting their similar drought sensitivity. Similar concentrations and seasonal dynamics of NSC in both rootstock combinations, together with their similar spring growth rates, suggest that NSC reserves were not directly limiting for growth. Our results support the prominent role of water relations in rootstock-induced size-controlling mechanisms and highlight the complexity of this topic.
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Affiliation(s)
- Radek Jupa
- Department of Biology, Faculty of Science, University of Hradec Králové, Rokitanského 62, Hradec Králové CZ-500 03, Czech Republic
| | - Martin Mészáros
- Department of Technology, Research and Breeding Institute of Pomology, Research and Breeding Institute of Pomology, Holovousy 129, Hořice CZ-508 01, Czech Republic
| | - Günter Hoch
- Department of Environmental Sciences - Botany, University of Basel, Schönbeinstrasse 6, 4056 Basel, Switzerland
| | - Lenka Plavcová
- Department of Biology, Faculty of Science, University of Hradec Králové, Rokitanského 62, Hradec Králové CZ-500 03, Czech Republic
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Körner C. The cold range limit of trees. Trends Ecol Evol 2021; 36:979-989. [PMID: 34272073 DOI: 10.1016/j.tree.2021.06.011] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 06/13/2021] [Accepted: 06/21/2021] [Indexed: 11/27/2022]
Abstract
At high elevation or latitude, trees reach low-temperature range limits. In attempting an explanation, the range limits of individual tree species (set by freezing tolerance) and the general limit of the life-form tree (set by thermal growth constraints) need to be distinguished. The general cold edge of the fundamental niche of trees is termed the treeline, by definition, the lower edge of the alpine belt, a most important bioclimatological reference line. Trees can be absent from the treeline due to disturbances or biotic interactions. The actual local edge of tree distribution, the delineation of the realized niche, is driven by stochastic effects. Therefore, treeline theory and hypothesis testing is inevitably tied to the fundamental niche concept.
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Affiliation(s)
- Christian Körner
- Department of Environmental Sciences, Botany, University of Basel, Schönbeinstrasse 6, 4056 Basel, Switzerland.
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Affiliation(s)
- Christine R. Rollinson
- Center for Tree Science, The Morton Arboretum, 4100 Illinois Route 53, Lisle, IL 60532, USA
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Dolezal J, Kurnotova M, Stastna P, Klimesova J. Alpine plant growth and reproduction dynamics in a warmer world. THE NEW PHYTOLOGIST 2020; 228:1295-1305. [PMID: 32632948 DOI: 10.1111/nph.16790] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Accepted: 06/26/2020] [Indexed: 05/23/2023]
Abstract
Climate warming may stimulate growth and reproduction in cold-adapted plants, but also reduce their performance due to warming-induced drought limitation. We tested this theory using a unique experiment with the alpine forb Rumex alpinus. We examined how climate warming over the past four decades affected its annual rhizome growth, leaf production and flowering, and whether responses varied between alpine, subalpine and montane populations. Before the period of accelerated warming in the 1970s and 1980s, the primary limitation on growth had been cold temperatures and short growing seasons. Increased summer temperatures in the 1990s and 2000s enhanced rhizome growth and leaf production, but not flowering. Alpine and subalpine plants profit more than montane plants, currently producing three times longer annual rhizome increments and twice as many leaves as 40 yr ago, and achieving nearly the same values as montane plants. During the warmest 2005-2015 period, growth became contingent on summer precipitation and began to decrease across all populations, likely due to an increasing water shortage in dense monospecific stands. Warming releases plants from cold limitations but induces water shortage. Rumex alpinus exceeds its thermal optimum and becomes water-limited as the climate warms. Our results suggest that warming-induced responses in alpine plants will not be one-sided shifts to higher growth and reproduction, but rather multidimensional and spatiotemporally variable.
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Affiliation(s)
- Jiri Dolezal
- Institute of Botany of the Czech Academy of Science, Dukelská 135, Třeboň, CZ-379 01, Czech Republic
- Faculty of Science, University of South Bohemia, Branišovská 31, České Budějovice, CZ-370 05, Czech Republic
| | - Margareta Kurnotova
- Faculty of Science, University of South Bohemia, Branišovská 31, České Budějovice, CZ-370 05, Czech Republic
| | - Petra Stastna
- Krkonoše Mts. National Park Administration, Dobrovského 3, Vrchlabí, CZ-543 01, Czech Republic
| | - Jitka Klimesova
- Institute of Botany of the Czech Academy of Science, Dukelská 135, Třeboň, CZ-379 01, Czech Republic
- Department of Botany, Faculty of Science, Charles University, Benátská 2, Prague, CZ-120 01, Czech Republic
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Casolo V, Braidot E, Petrussa E, Zancani M, Vianello A, Boscutti F. Relationships between population traits, nonstructural carbohydrates, and elevation in alpine stands of Vaccinium myrtillus. AMERICAN JOURNAL OF BOTANY 2020; 107:639-649. [PMID: 32239489 PMCID: PMC7217170 DOI: 10.1002/ajb2.1458] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Accepted: 01/30/2020] [Indexed: 06/11/2023]
Abstract
PREMISE Despite great attention given to the relationship between plant growth and carbon balance in alpine tree species, little is known about shrubs at the treeline. We hypothesized that the pattern of main nonstructural carbohydrates (NSCs) across elevations depends on the interplay between phenotypic trait plasticity, plant-plant interaction, and elevation. METHODS We studied the pattern of NSCs (i.e., glucose, fructose, sucrose, and starch) in alpine stands of Vaccinium myrtillus (above treeline) across an elevational gradient. In the same plots, we measured key growth traits (i.e., anatomical stem features) and shrub cover, evaluating putative relationships with NSCs. RESULTS Glucose content was positively related with altitude, but negatively related with shrub cover. Sucrose decreased at high altitude and in older populations and increased with higher percentage of vascular tissue. Starch content increased at middle and high elevations and in stands with high shrub cover. Moreover, starch content was negatively related with the number of xylem rings and the percentage of phloem tissue, but positively correlated with the percentage of xylem tissue. CONCLUSIONS We found that the increase in carbon reserves across elevations was uncoupled from plant growth, supporting the growth limitation hypothesis, which postulates NSCs accumulate at high elevation as a consequence of low temperature. Moreover, the response of NSC content to the environmental stress caused by elevation was buffered by phenotypic plasticity of plant traits, suggesting that, under climate warming conditions, shrub expansion due to enhanced plant growth would be pronounced in old but sparse stands.
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Affiliation(s)
- Valentino Casolo
- Department of Agriculture, Food, Environmental and Animal SciencesPlant Biology UnitUniversity of Udinevia delle Scienze 9133100UdineItaly
| | - Enrico Braidot
- Department of Agriculture, Food, Environmental and Animal SciencesPlant Biology UnitUniversity of Udinevia delle Scienze 9133100UdineItaly
| | - Elisa Petrussa
- Department of Agriculture, Food, Environmental and Animal SciencesPlant Biology UnitUniversity of Udinevia delle Scienze 9133100UdineItaly
| | - Marco Zancani
- Department of Agriculture, Food, Environmental and Animal SciencesPlant Biology UnitUniversity of Udinevia delle Scienze 9133100UdineItaly
| | - Angelo Vianello
- Department of Agriculture, Food, Environmental and Animal SciencesPlant Biology UnitUniversity of Udinevia delle Scienze 9133100UdineItaly
| | - Francesco Boscutti
- Department of Agriculture, Food, Environmental and Animal SciencesPlant Biology UnitUniversity of Udinevia delle Scienze 9133100UdineItaly
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Panthi S, Fan ZX, van der Sleen P, Zuidema PA. Long-term physiological and growth responses of Himalayan fir to environmental change are mediated by mean climate. GLOBAL CHANGE BIOLOGY 2020; 26:1778-1794. [PMID: 31696994 DOI: 10.1111/gcb.14910] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Accepted: 10/23/2019] [Indexed: 06/10/2023]
Abstract
High-elevation forests are experiencing high rates of warming, in combination with CO2 rise and (sometimes) drying trends. In these montane systems, the effects of environmental changes on tree growth are also modified by elevation itself, thus complicating our ability to predict effects of future climate change. Tree-ring analysis along an elevation gradient allows quantifying effects of gradual and annual environmental changes. Here, we study long-term physiological (ratio of internal to ambient CO2 , i.e., Ci /Ca and intrinsic water-use efficiency, iWUE) and growth responses (tree-ring width) of Himalayan fir (Abies spectabilis) trees in response to warming, drying, and CO2 rise. Our study was conducted along elevational gradients in a dry and a wet region in the central Himalaya. We combined dendrochronology and stable carbon isotopes (δ13 C) to quantify long-term trends in Ci /Ca ratio and iWUE (δ13 C-derived), growth (mixed-effects models), and evaluate climate sensitivity (correlations). We found that iWUE increased over time at all elevations, with stronger increase in the dry region. Climate-growth relations showed growth-limiting effects of spring moisture (dry region) and summer temperature (wet region), and negative effects of temperature (dry region). We found negative growth trends at lower elevations (dry and wet regions), suggesting that continental-scale warming and regional drying reduced tree growth. This interpretation is supported by δ13 C-derived long-term physiological responses, which are consistent with responses to reduced moisture and increased vapor pressure deficit. At high elevations (wet region), we found positive growth trends, suggesting that warming has favored tree growth in regions where temperature most strongly limits growth. At lower elevations (dry and wet regions), the positive effects of CO2 rise did not mitigate the negative effects of warming and drying on tree growth. Our results raise concerns on the productivity of Himalayan fir forests at low and middle (<3,300 m) elevations as climate change progresses.
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Affiliation(s)
- Shankar Panthi
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden of the Chinese Academy of Sciences, Mengla, Yunnan, China
- Center for Plant Ecology, Chinese Academy of Sciences, Xishuangbanna, China
| | - Ze-Xin Fan
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden of the Chinese Academy of Sciences, Mengla, Yunnan, China
- Center for Plant Ecology, Chinese Academy of Sciences, Xishuangbanna, China
- Ailaoshan Station of Subtropical Forest Ecosystem Studies, Xishuangbanna Tropical Botanical Garden of the Chinese Academy of Sciences, Jingdong, Yunnan, China
| | - Peter van der Sleen
- Department of Wetland Ecology, Karlsruhe Institute of Technology, Rastatt, Germany
| | - Pieter A Zuidema
- Forest Ecology & Forest Management Group, Wageningen University, Wageningen, The Netherlands
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