151
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Grainger TN, Gilbert B. Multi-scale responses to warming in an experimental insect metacommunity. GLOBAL CHANGE BIOLOGY 2017; 23:5151-5163. [PMID: 28556493 DOI: 10.1111/gcb.13777] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Accepted: 05/22/2017] [Indexed: 05/24/2023]
Abstract
In metacommunities, diversity is the product of species interactions at the local scale and dispersal between habitat patches at the regional scale. Although warming can alter both species interactions and dispersal, the combined effects of warming on these two processes remains uncertain. To determine the independent and interactive effects of warming-induced changes to local species interactions and dispersal, we constructed experimental metacommunities consisting of enclosed milkweed patches seeded with five herbivorous milkweed specialist insect species. We treated metacommunities with two levels of warming (unwarmed and warmed) and three levels of connectivity (isolated, low connectivity, high connectivity). Based on metabolic theory, we predicted that if plant resources were limited, warming would accelerate resource drawdown, causing local insect declines and increasing both insect dispersal and the importance of connectivity to neighboring patches for insect persistence. Conversely, given abundant resources, warming could have positive local effects on insects, and the risk of traversing a corridor to reach a neighboring patch could outweigh the benefits of additional resources. We found support for the latter scenario. Neither resource drawdown nor the weak insect-insect associations in our system were affected by warming, and most insect species did better locally in warmed conditions and had dispersal responses that were unchanged or indirectly affected by warming. Dispersal across the matrix posed a species-specific risk that led to declines in two species in connected metacommunities. Combined, this scaled up to cause an interactive effect of warming and connectivity on diversity, with unwarmed metacommunities with low connectivity incurring the most rapid declines in diversity. Overall, this study demonstrates the importance of integrating the complex outcomes of species interactions and spatial structure in understanding community response to climate change.
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Affiliation(s)
- Tess Nahanni Grainger
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada
| | - Benjamin Gilbert
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada
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152
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Parker TC, Tang J, Clark MB, Moody MM, Fetcher N. Ecotypic differences in the phenology of the tundra species Eriophorum vaginatum reflect sites of origin. Ecol Evol 2017; 7:9775-9786. [PMID: 29188008 PMCID: PMC5696421 DOI: 10.1002/ece3.3445] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Revised: 07/14/2017] [Accepted: 08/31/2017] [Indexed: 01/19/2023] Open
Abstract
Eriophorum vaginatum is a tussock-forming sedge that contributes significantly to the structure and primary productivity of moist acidic tussock tundra. Locally adapted populations (ecotypes) have been identified across the geographical distribution of E. vaginatum; however, little is known about how their growth and phenology differ over the course of a growing season. The growing season is short in the Arctic and therefore exerts a strong selection pressure on tundra species. This raises the hypothesis that the phenology of arctic species may be poorly adapted if the timing and length of the growing season change. Mature E. vaginatum tussocks from across a latitudinal gradient (65-70°N) were transplanted into a common garden at a central location (Toolik Lake, 68°38'N, 149°36'W) where half were warmed using open-top chambers. Over two growing seasons (2015 and 2016), leaf length was measured weekly to track growth rates, timing of senescence, and biomass accumulation. Growth rates were similar across ecotypes and between years and were not affected by warming. However, southern populations accumulated significantly more biomass, largely because they started to senesce later. In 2016, peak biomass and senescence of most populations occurred later than in 2015, probably induced by colder weather at the beginning of the growing season in 2016, which caused a delayed start to growth. The finish was delayed as well. Differences in phenology between populations were largely retained between years, suggesting that the amount of time that these ecotypes grow has been selected by the length of the growing seasons at their respective home sites. As potential growing seasons lengthen, E. vaginatum may be unable to respond appropriately as a result of genetic control and may have reduced fitness in the rapidly warming Arctic tundra.
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Affiliation(s)
- Thomas C. Parker
- The Ecosystems CenterMarine Biological LaboratoryWoods HoleMAUSA
- Present address:
Biological and Environmental SciencesFaculty of Natural SciencesUniversity of StirlingStirlingUK
| | - Jianwu Tang
- The Ecosystems CenterMarine Biological LaboratoryWoods HoleMAUSA
| | - Mahalia B. Clark
- The Ecosystems CenterMarine Biological LaboratoryWoods HoleMAUSA
| | | | - Ned Fetcher
- Institute for Environmental Science and SustainabilityWilkes UniversityWilkes‐BarrePAUSA
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153
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Weijers S, Buchwal A, Blok D, Löffler J, Elberling B. High Arctic summer warming tracked by increased Cassiope tetragona growth in the world's northernmost polar desert. GLOBAL CHANGE BIOLOGY 2017; 23:5006-5020. [PMID: 28464494 DOI: 10.1111/gcb.13747] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Revised: 04/18/2017] [Accepted: 04/24/2017] [Indexed: 06/07/2023]
Abstract
Rapid climate warming has resulted in shrub expansion, mainly of erect deciduous shrubs in the Low Arctic, but the more extreme, sparsely vegetated, cold and dry High Arctic is generally considered to remain resistant to such shrub expansion in the next decades. Dwarf shrub dendrochronology may reveal climatological causes of past changes in growth, but is hindered at many High Arctic sites by short and fragmented instrumental climate records. Moreover, only few High Arctic shrub chronologies cover the recent decade of substantial warming. This study investigated the climatic causes of growth variability of the evergreen dwarf shrub Cassiope tetragona between 1927 and 2012 in the northernmost polar desert at 83°N in North Greenland. We analysed climate-growth relationships over the period with available instrumental data (1950-2012) between a 102-year-long C. tetragona shoot length chronology and instrumental climate records from the three nearest meteorological stations, gridded climate data, and North Atlantic Oscillation (NAO) and Arctic Oscillation (AO) indices. July extreme maximum temperatures (JulTemx ), as measured at Alert, Canada, June NAO, and previous October AO, together explained 41% of the observed variance in annual C. tetragona growth and likely represent in situ summer temperatures. JulTemx explained 27% and was reconstructed back to 1927. The reconstruction showed relatively high growing season temperatures in the early to mid-twentieth century, as well as warming in recent decades. The rapid growth increase in C. tetragona shrubs in response to recent High Arctic summer warming shows that recent and future warming might promote an expansion of this evergreen dwarf shrub, mainly through densification of existing shrub patches, at High Arctic sites with sufficient winter snow cover and ample water supply during summer from melting snow and ice as well as thawing permafrost, contrasting earlier notions of limited shrub growth sensitivity to summer warming in the High Arctic.
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Affiliation(s)
- Stef Weijers
- Department of Geography, University of Bonn, Bonn, Germany
| | - Agata Buchwal
- Institute of Geoecology and Geoinformation, Adam Mickiewicz University, Poznan, Poland
- Department of Biological Sciences, Ecosystem and Biomedical Lab, University of Alaska Anchorage, Anchorage, AK, USA
| | - Daan Blok
- Department of Physical Geography and Ecosystem Science, Lund University, Lund, Sweden
| | - Jörg Löffler
- Department of Geography, University of Bonn, Bonn, Germany
| | - Bo Elberling
- Center for Permafrost (CENPERM), Department of Geosciences and Natural Resource Management, University of Copenhagen, Copenhagen, Denmark
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154
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Scrine J, Jochum M, Ólafsson JS, O'Gorman EJ. Interactive effects of temperature and habitat complexity on freshwater communities. Ecol Evol 2017; 7:9333-9346. [PMID: 29187972 PMCID: PMC5696415 DOI: 10.1002/ece3.3412] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Revised: 07/28/2017] [Accepted: 08/03/2017] [Indexed: 11/11/2022] Open
Abstract
Warming can lead to increased growth of plants or algae at the base of the food web, which may increase the overall complexity of habitat available for other organisms. Temperature and habitat complexity have both been shown to alter the structure and functioning of communities, but they may also have interactive effects, for example, if the shade provided by additional habitat negates the positive effect of temperature on understory plant or algal growth. This study explored the interactive effects of these two major environmental factors in a manipulative field experiment, by assessing changes in ecosystem functioning (primary production and decomposition) and community structure in the presence and absence of artificial plants along a natural stream temperature gradient of 5-18°C. There was no effect of temperature or habitat complexity on benthic primary production, but epiphytic production increased with temperature in the more complex habitat. Cellulose decomposition rate increased with temperature, but was unaffected by habitat complexity. Macroinvertebrate communities were less similar to each other as temperature increased, while habitat complexity only altered community composition in the coldest streams. There was also an overall increase in macroinvertebrate abundance, body mass, and biomass in the warmest streams, driven by increasing dominance of snails and blackfly larvae. Presence of habitat complexity, however, dampened the strength of this temperature effect on the abundance of macroinvertebrates in the benthos. The interactive effects that were observed suggest that habitat complexity can modify the effects of temperature on important ecosystem functions and community structure, which may alter energy flow through the food web. Given that warming is likely to increase habitat complexity, particularly at higher latitudes, more studies should investigate these two major environmental factors in combination to improve our ability to predict the impacts of future global change.
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Affiliation(s)
- Jennifer Scrine
- Imperial College LondonSilwood Park CampusBuckhurst Road, AscotBerkshireSL5 7PYUK
| | - Malte Jochum
- Institute of Plant SciencesUniversity of BernBernSwitzerland
- J.F. Blumenbach Institute of Zoology and AnthropologyUniversity of GoettingenGöttingenGermany
| | | | - Eoin J. O'Gorman
- Imperial College LondonSilwood Park CampusBuckhurst Road, AscotBerkshireSL5 7PYUK
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155
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Vowles T, Gunnarsson B, Molau U, Hickler T, Klemedtsson L, Björk RG. Expansion of deciduous tall shrubs but not evergreen dwarf shrubs inhibited by reindeer in Scandes mountain range. THE JOURNAL OF ECOLOGY 2017; 105:1547-1561. [PMID: 29200500 PMCID: PMC5697633 DOI: 10.1111/1365-2745.12753] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Accepted: 01/12/2017] [Indexed: 06/02/2023]
Abstract
One of the most palpable effects of warming in Arctic ecosystems is shrub expansion above the tree line. However, previous studies have found that reindeer can influence plant community responses to warming and inhibit shrubification of the tundra.We revisited grazed (ambient) and ungrazed study plots (exclosures), at the southern as well as the northern limits of the Swedish alpine region, to study long-term grazing effects and vegetation changes in response to increasing temperatures between 1995 and 2011, in two vegetation types (shrub heath and mountain birch forest).In the field layer at the shrub heath sites, evergreen dwarf shrubs had increased in cover from 26% to 49% but were unaffected by grazing. Deciduous dwarf and tall shrubs also showed significant, though smaller, increases over time. At the birch forest sites, the increase was similar for evergreen dwarf shrubs (20-48%) but deciduous tall shrubs did not show the same consistent increase over time as in the shrub heath.The cover and height of the shrub layer were significantly greater in exclosures at the shrub heath sites, but no significant treatment effects were found on species richness or diversity.July soil temperatures and growing season thawing degree days (TDD) were higher in exclosures at all but one site, and there was a significant negative correlation between mean shrub layer height and soil TDD at the shrub heath sites. Synthesis. This study shows that shrub expansion is occurring rapidly in the Scandes mountain range, both above and below the tree line. Tall, deciduous shrubs had benefitted significantly from grazing exclosure, both in terms of cover and height, which in turn lowered summer soil temperatures. However, the overriding vegetation shift across our sites was the striking increase in evergreen dwarf shrubs, which were not influenced by grazing. As the effects of an increase in evergreen dwarf shrubs and more recalcitrant plant litter may to some degree counteract some of the effects of an increase in deciduous tall shrubs, herbivore influence on shrub interactions is potentially of great importance for shaping arctic shrub expansion and its associated ecosystem effects.
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Affiliation(s)
- Tage Vowles
- Department of Biological and Environmental SciencesUniversity of GothenburgBox 46140530GöteborgSweden
| | - Bengt Gunnarsson
- Department of Biological and Environmental SciencesUniversity of GothenburgBox 46140530GöteborgSweden
| | - Ulf Molau
- Department of Biological and Environmental SciencesUniversity of GothenburgBox 46140530GöteborgSweden
| | - Thomas Hickler
- Senckenberg Biodiversity & Climate Research Centre Bik FSenckenberganalge 25D‐60325FrankfurtGermany
- Department of Physical GeographyGoethe University FrankfurtAltenhöferallee 1D‐60438FrankfurtGermany
| | - Leif Klemedtsson
- Department of Earth SciencesUniversity of GothenburgBox 46040530GöteborgSweden
| | - Robert G. Björk
- Department of Earth SciencesUniversity of GothenburgBox 46040530GöteborgSweden
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156
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Nabe-Nielsen J, Normand S, Hui FKC, Stewart L, Bay C, Nabe-Nielsen LI, Schmidt NM. Plant community composition and species richness in the High Arctic tundra: From the present to the future. Ecol Evol 2017; 7:10233-10242. [PMID: 29238550 PMCID: PMC5723606 DOI: 10.1002/ece3.3496] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Revised: 08/25/2017] [Accepted: 09/02/2017] [Indexed: 11/23/2022] Open
Abstract
Arctic plant communities are altered by climate changes. The magnitude of these alterations depends on whether species distributions are determined by macroclimatic conditions, by factors related to local topography, or by biotic interactions. Our current understanding of the relative importance of these conditions is limited due to the scarcity of studies, especially in the High Arctic. We investigated variations in vascular plant community composition and species richness based on 288 plots distributed on three sites along a coast‐inland gradient in Northeast Greenland using a stratified random design. We used an information theoretic approach to determine whether variations in species richness were best explained by macroclimate, by factors related to local topography (including soil water) or by plant‐plant interactions. Latent variable models were used to explain patterns in plant community composition. Species richness was mainly determined by variations in soil water content, which explained 35% of the variation, and to a minor degree by other variables related to topography. Species richness was not directly related to macroclimate. Latent variable models showed that 23.0% of the variation in community composition was explained by variables related to topography, while distance to the inland ice explained an additional 6.4 %. This indicates that some species are associated with environmental conditions found in only some parts of the coast–inland gradient. Inclusion of macroclimatic variation increased the model's explanatory power by 4.2%. Our results suggest that the main impact of climate changes in the High Arctic will be mediated by their influence on local soil water conditions. Increasing temperatures are likely to cause higher evaporation rates and alter the distribution of late‐melting snow patches. This will have little impact on landscape‐scale diversity if plants are able to redistribute locally to remain in areas with sufficient soil water.
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Affiliation(s)
- Jacob Nabe-Nielsen
- Department of Bioscience Aarhus University Roskilde Denmark.,Arctic Research Centre (ARC) Aarhus University Aarhus C Denmark
| | - Signe Normand
- Department of Bioscience Aarhus University Aarhus C Denmark
| | - Francis K C Hui
- Mathematical Sciences Institute The Australian National University Acton ACT Australia
| | - Lærke Stewart
- Department of Bioscience Aarhus University Roskilde Denmark.,Arctic Research Centre (ARC) Aarhus University Aarhus C Denmark
| | - Christian Bay
- Department of Bioscience Aarhus University Roskilde Denmark.,Arctic Research Centre (ARC) Aarhus University Aarhus C Denmark
| | | | - Niels Martin Schmidt
- Department of Bioscience Aarhus University Roskilde Denmark.,Arctic Research Centre (ARC) Aarhus University Aarhus C Denmark
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157
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Regional Quantitative Cover Mapping of Tundra Plant Functional Types in Arctic Alaska. REMOTE SENSING 2017. [DOI: 10.3390/rs9101024] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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158
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Liu D, Estiarte M, Ogaya R, Yang X, Peñuelas J. Shift in community structure in an early-successional Mediterranean shrubland driven by long-term experimental warming and drought and natural extreme droughts. GLOBAL CHANGE BIOLOGY 2017; 23:4267-4279. [PMID: 28514052 DOI: 10.1111/gcb.13763] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2017] [Accepted: 04/24/2017] [Indexed: 05/26/2023]
Abstract
Global warming and recurring drought are expected to accelerate water limitation for plant communities in semiarid Mediterranean ecosystems and produce directional shifts in structure and composition that are not easily detected, and supporting evidence is scarce. We conducted a long-term (17 years) nocturnal-warming (+0.6°C) and drought (-40% rainfall) experiments in an early-successional Mediterranean shrubland to study the changes in community structure and composition, contrasting functional groups and dominant species, and the superimposed effects of natural extreme drought. Species richness decreased in both the warming and drought treatments. Responses to the moderate warming were associated with decreases in herb abundance, and responses to the drought were associated with decreases in both herb and shrub abundances. The drought also significantly decreased community diversity and evenness. Changes in abundance differed between herbs (decreases) and shrubs (increases or no changes). Both warming and drought, especially drought, increased the relative species richness and abundance of shrubs, favoring the establishment of shrubs. Both warming and drought produced significant shifts in plant community composition. Experimental warming shifted the community composition from Erica multiflora toward Rosmarinus officinalis, and drought consistently shifted the composition toward Globularia alypum. The responses in biodiversity (e.g., community biodiversity, changes of functional groups and compositional shifts) were also strongly correlated with atmospheric drought (SPEI) in winter-spring and/or summer, indicating sensitivity to water limitation in this early-successional Mediterranean ecosystem, especially to natural extreme droughts. Our results suggest that the shifts in species assembles and community diversity and composition are accelerated by the long-term nocturnal-warming and drought, combined with natural severe droughts, and that the magnitude of the impacts of climate change is also correlated with the successional status of ecosystem. The results thus highlight the necessity for assessing the impacts on ecosystemic functioning and services and developing effective measures for conserving biodiversity.
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Affiliation(s)
- Daijun Liu
- Global Ecology Unit CREAF-CSIC-UAB, CSIC, Bellaterra, Spain
- CREAF, Cerdanyola del Vallès, Spain
| | - Marc Estiarte
- Global Ecology Unit CREAF-CSIC-UAB, CSIC, Bellaterra, Spain
- CREAF, Cerdanyola del Vallès, Spain
| | - Romà Ogaya
- Global Ecology Unit CREAF-CSIC-UAB, CSIC, Bellaterra, Spain
- CREAF, Cerdanyola del Vallès, Spain
| | - Xiaohong Yang
- Key Laboratory of Horticulture Science for Southern Mountainous Regions, Ministry of Education, Southwest University, Chongqing, China
| | - Josep Peñuelas
- Global Ecology Unit CREAF-CSIC-UAB, CSIC, Bellaterra, Spain
- CREAF, Cerdanyola del Vallès, Spain
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159
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White-Monsant AC, Clark GJ, Ng Kam Chuen MAG, Tang C. Experimental warming and antecedent fire alter leaf element composition and increase soil C:N ratio in sub-alpine open heathland. THE SCIENCE OF THE TOTAL ENVIRONMENT 2017; 595:41-50. [PMID: 28376427 DOI: 10.1016/j.scitotenv.2017.03.237] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2017] [Revised: 03/25/2017] [Accepted: 03/25/2017] [Indexed: 06/07/2023]
Abstract
Plant communities in alpine ecosystems worldwide are being altered by climate warming. In the alpine open heathland of the Bogong High Plains, Australia, warming and fire have affected the growth and phenology of plants, and have recently been found to alter soil nutrient availability. We examined the effects of nine years of passive warming by open-top chambers and nine years post-fire on (i) the soluble and extractable nutrients and toxic elements available for plant uptake in the soil and (ii) on the element composition of leaves of seven dominant sub-alpine open heathland plants. Warming increased soil C, soil C:N, and decreased soil δ13C, indicating an accumulation of soil organic matter and C sequestration. Warming increased soil δ15N, indicating increased N mineralization, which concurred with the increased availability of NH4+ (measured by ion-exchange membranes). Leaf element composition varied among the plant species in response to changes in soil element availabilities, suggesting the importance of species-specific knowledge. Warming decreased leaf N concentration and increased leaf C:N, generally in the plant community, and specifically in Asterolasia trymalioides, Carex breviculmis, Poa hiemata, and Rytidosperma nudiflorum. Warming increased soil P availability, but did not significantly affect leaf P in any species. Antecedent fire increased soil C:N, and decreased concentrations of Ca and Mg in Celmisia pugioniformis more than in the other species. The results suggest that warming and fire changed the nutrient composition of plants and increased soil C:N, which might lead to progressive N limitation in the alpine ecosystem.
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Affiliation(s)
- A C White-Monsant
- Department of Animal, Plant and Soil Sciences, Centre for Agribiosciences, La Trobe University, Bundoora, VIC 3086, Australia.
| | - G J Clark
- Department of Animal, Plant and Soil Sciences, Centre for Agribiosciences, La Trobe University, Bundoora, VIC 3086, Australia
| | - M A G Ng Kam Chuen
- Department of Animal, Plant and Soil Sciences, Centre for Agribiosciences, La Trobe University, Bundoora, VIC 3086, Australia
| | - C Tang
- Department of Animal, Plant and Soil Sciences, Centre for Agribiosciences, La Trobe University, Bundoora, VIC 3086, Australia
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160
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Geml J, Semenova TA, Morgado LN, Welker JM. Changes in composition and abundance of functional groups of arctic fungi in response to long-term summer warming. Biol Lett 2017; 12:rsbl.2016.0503. [PMID: 27881760 PMCID: PMC5134034 DOI: 10.1098/rsbl.2016.0503] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Accepted: 10/28/2016] [Indexed: 11/12/2022] Open
Abstract
We characterized fungal communities in dry and moist tundra and investigated the effect of long-term experimental summer warming on three aspects of functional groups of arctic fungi: richness, community composition and species abundance. Warming had profound effects on community composition, abundance, and, to a lesser extent, on richness of fungal functional groups. In addition, our data show that even within functional groups, the direction and extent of response to warming tend to be species-specific and we recommend that studies on fungal communities and their roles in nutrient cycling take into account species-level responses.
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Affiliation(s)
- József Geml
- Naturalis Biodiversity Center, PO Box 9517, 2300 RA Leiden, The Netherlands .,Faculty of Science, Leiden University, PO Box 9502, 2300 RA Leiden, The Netherlands
| | - Tatiana A Semenova
- Naturalis Biodiversity Center, PO Box 9517, 2300 RA Leiden, The Netherlands.,Faculty of Science, Leiden University, PO Box 9502, 2300 RA Leiden, The Netherlands
| | - Luis N Morgado
- Naturalis Biodiversity Center, PO Box 9517, 2300 RA Leiden, The Netherlands
| | - Jeffrey M Welker
- Department of Biological Sciences, University of Alaska Anchorage, Anchorage, AK 99508, USA
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161
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Welshofer KB, Zarnetske PL, Lany NK, Thompson LA. Open‐top chambers for temperature manipulation in taller‐stature plant communities. Methods Ecol Evol 2017. [DOI: 10.1111/2041-210x.12863] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Kileigh B. Welshofer
- Department of Forestry Michigan State University East Lansing MI USA
- Ecology, Evolutionary Biology, and Behavior Program East Lansing MI USA
| | - Phoebe L. Zarnetske
- Department of Forestry Michigan State University East Lansing MI USA
- Ecology, Evolutionary Biology, and Behavior Program East Lansing MI USA
- Department of Fisheries & Wildlife Michigan State University East Lansing MI USA
| | - Nina K. Lany
- Department of Forestry Michigan State University East Lansing MI USA
- Ecology, Evolutionary Biology, and Behavior Program East Lansing MI USA
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162
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Herbivores rescue diversity in warming tundra by modulating trait-dependent species losses and gains. Nat Commun 2017; 8:419. [PMID: 28871154 PMCID: PMC5583392 DOI: 10.1038/s41467-017-00554-z] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Accepted: 07/10/2017] [Indexed: 11/08/2022] Open
Abstract
Climate warming is altering the diversity of plant communities but it remains unknown which species will be lost or gained under warming, especially considering interactions with other factors such as herbivory and nutrient availability. Here, we experimentally test effects of warming, mammalian herbivory and fertilization on tundra species richness and investigate how plant functional traits affect losses and gains. We show that herbivory reverses the impact of warming on diversity: in the presence of herbivores warming increases species richness through higher species gains and lower losses, while in the absence of herbivores warming causes higher species losses and thus decreases species richness. Herbivores promote gains of short-statured species under warming, while herbivore removal and fertilization increase losses of short-statured and resource-conservative species through light limitation. Our results demonstrate that both rarity and traits forecast species losses and gains, and mammalian herbivores are essential for preventing trait-dependent extinctions and mitigate diversity loss under warming and eutrophication. Warming can reduce plant diversity but it is unclear which species will be lost or gained under interacting global changes. Kaarlejärvi et al. manipulate temperature, herbivory and nutrients in a tundra system and find that herbivory maintains diversity under warming by reducing species losses and promoting gains.
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163
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Milbau A, Vandeplas N, Kockelbergh F, Nijs I. Both seed germination and seedling mortality increase with experimental warming and fertilization in a subarctic tundra. AOB PLANTS 2017; 9:plx040. [PMID: 29026511 PMCID: PMC5629451 DOI: 10.1093/aobpla/plx040] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Accepted: 08/30/2017] [Indexed: 05/28/2023]
Abstract
Climate change is expected to force many species in arctic regions to migrate and track their climatic niche. This requires recruitment from seed, which currently shows very low rates in arctic regions, where long-lived and vegetatively reproducing plants dominate. Therefore, we pose the question whether recruitment (germination and seedling establishment) in arctic regions will significantly improve in a warmer world, and thus allow species to follow their climatic niche. We used a full factorial experiment to examine if realistic warmer temperatures (+3 °C; infrared radiation) and increased nitrogen availability (+1.4 g N m-2 year-1) affected germination, seedling survival and above- and below-ground seedling biomass in five species common in subarctic regions (Anthoxanthum odoratum, Betula nana, Pinus sylvestris, Solidago virgaurea, Vaccinium myrtillus). We found that warming increased seedling emergence in all species, but that subsequent mortality also increased, resulting in no net warming effect on seedling establishment. Warming slightly increased above-ground seedling biomass. Fertilization, on the other hand, did not influence seedling biomass, but it increased seedling establishment in B. nana while it reduced establishment in V. myrtillus. This may help B. nana dominate over V. myrtillus in warmer tundra. Surprisingly, no interactive effects between warming and fertilization were found. The lack of a general positive response of seedling establishment to warmer and more nutrient-rich conditions suggests that (sub)arctic species may experience difficulties in tracking their climatic niche. Predictions of future species distributions in arctic regions solely based on abiotic factors may therefore overestimate species' ranges due to their poor establishment. Also, the opposite response to fertilization of two key (sub)arctic dwarf shrubs, i.e. B. nana and V. myrtillus, could have important implications for the future development of arctic plant communities and argues for more research into the role of fertilization for plant establishment.
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Affiliation(s)
- Ann Milbau
- Research Institute for Nature and Forest (INBO), Kliniekstraat 25, 1070 Brussels, Belgium
| | - Nicolas Vandeplas
- Research Group of Plant and Vegetation Ecology (PLECO), Department of Biology, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium
| | - Fred Kockelbergh
- Research Group of Plant and Vegetation Ecology (PLECO), Department of Biology, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium
| | - Ivan Nijs
- Research Group of Plant and Vegetation Ecology (PLECO), Department of Biology, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium
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164
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Yu Q, Epstein H, Engstrom R, Walker D. Circumpolar arctic tundra biomass and productivity dynamics in response to projected climate change and herbivory. GLOBAL CHANGE BIOLOGY 2017; 23:3895-3907. [PMID: 28276177 DOI: 10.1111/gcb.13632] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Accepted: 12/20/2016] [Indexed: 06/06/2023]
Abstract
Satellite remote sensing data have indicated a general 'greening' trend in the arctic tundra biome. However, the observed changes based on remote sensing are the result of multiple environmental drivers, and the effects of individual controls such as warming, herbivory, and other disturbances on changes in vegetation biomass, community structure, and ecosystem function remain unclear. We apply ArcVeg, an arctic tundra vegetation dynamics model, to estimate potential changes in vegetation biomass and net primary production (NPP) at the plant community and functional type levels. ArcVeg is driven by soil nitrogen output from the Terrestrial Ecosystem Model, existing densities of Rangifer populations, and projected summer temperature changes by the NCAR CCSM4.0 general circulation model across the Arctic. We quantified the changes in aboveground biomass and NPP resulting from (i) observed herbivory only; (ii) projected climate change only; and (iii) coupled effects of projected climate change and herbivory. We evaluated model outputs of the absolute and relative differences in biomass and NPP by country, bioclimate subzone, and floristic province. Estimated potential biomass increases resulting from temperature increase only are approximately 5% greater than the biomass modeled due to coupled warming and herbivory. Such potential increases are greater in areas currently occupied by large or dense Rangifer herds such as the Nenets-occupied regions in Russia (27% greater vegetation increase without herbivores). In addition, herbivory modulates shifts in plant community structure caused by warming. Plant functional types such as shrubs and mosses were affected to a greater degree than other functional types by either warming or herbivory or coupled effects of the two.
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Affiliation(s)
- Qin Yu
- Department of Geography, The George Washington University, 1922F street NW, Washington, DC, 20052, USA
| | - Howard Epstein
- Department of Environmental Sciences, University of Virginia, 291 McCormick Rd, Charlottesville, VA, 22904, USA
| | - Ryan Engstrom
- Department of Geography, The George Washington University, 1922F street NW, Washington, DC, 20052, USA
| | - Donald Walker
- Arctic Geobotany Center, University of Alaska, Fairbanks, AK, USA
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165
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Mauritz M, Bracho R, Celis G, Hutchings J, Natali SM, Pegoraro E, Salmon VG, Schädel C, Webb EE, Schuur EAG. Nonlinear CO 2 flux response to 7 years of experimentally induced permafrost thaw. GLOBAL CHANGE BIOLOGY 2017; 23:3646-3666. [PMID: 28208232 DOI: 10.1111/gcb.13661] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2016] [Accepted: 01/19/2017] [Indexed: 06/06/2023]
Abstract
Rapid Arctic warming is expected to increase global greenhouse gas concentrations as permafrost thaw exposes immense stores of frozen carbon (C) to microbial decomposition. Permafrost thaw also stimulates plant growth, which could offset C loss. Using data from 7 years of experimental Air and Soil warming in moist acidic tundra, we show that Soil warming had a much stronger effect on CO2 flux than Air warming. Soil warming caused rapid permafrost thaw and increased ecosystem respiration (Reco ), gross primary productivity (GPP), and net summer CO2 storage (NEE). Over 7 years Reco , GPP, and NEE also increased in Control (i.e., ambient plots), but this change could be explained by slow thaw in Control areas. In the initial stages of thaw, Reco , GPP, and NEE increased linearly with thaw across all treatments, despite different rates of thaw. As thaw in Soil warming continued to increase linearly, ground surface subsidence created saturated microsites and suppressed Reco , GPP, and NEE. However Reco and GPP remained high in areas with large Eriophorum vaginatum biomass. In general NEE increased with thaw, but was more strongly correlated with plant biomass than thaw, indicating that higher Reco in deeply thawed areas during summer months was balanced by GPP. Summer CO2 flux across treatments fit a single quadratic relationship that captured the functional response of CO2 flux to thaw, water table depth, and plant biomass. These results demonstrate the importance of indirect thaw effects on CO2 flux: plant growth and water table dynamics. Nonsummer Reco models estimated that the area was an annual CO2 source during all years of observation. Nonsummer CO2 loss in warmer, more deeply thawed soils exceeded the increases in summer GPP, and thawed tundra was a net annual CO2 source.
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Affiliation(s)
- Marguerite Mauritz
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, USA
| | - Rosvel Bracho
- School of Forest Resources and Conservation, University of Florida, Gainesville, FL, USA
| | - Gerardo Celis
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, USA
| | - Jack Hutchings
- Department of Geological Sciences, University of Florida, Gainesville, FL, USA
| | | | - Elaine Pegoraro
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, USA
| | - Verity G Salmon
- Environmental Sciences Division and Climate Change Sciences Institute, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Christina Schädel
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, USA
| | - Elizabeth E Webb
- Department of Biology, University of Florida, Gainesville, FL, USA
| | - Edward A G Schuur
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, USA
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166
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Ashton GV, Morley SA, Barnes DKA, Clark MS, Peck LS. Warming by 1°C Drives Species and Assemblage Level Responses in Antarctica's Marine Shallows. Curr Biol 2017; 27:2698-2705.e3. [PMID: 28867203 DOI: 10.1016/j.cub.2017.07.048] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 06/20/2017] [Accepted: 07/21/2017] [Indexed: 10/19/2022]
Abstract
Forecasting assemblage-level responses to climate change remains one of the greatest challenges in global ecology [1, 2]. Data from the marine realm are limited because they largely come from experiments using limited numbers of species [3], mesocosms whose interior conditions are unnatural [4], and long-term correlation studies based on historical collections [5]. We describe the first ever experiment to warm benthic assemblages to ecologically relevant levels in situ. Heated settlement panels were used to create three test conditions: ambient and 1°C and 2°C above ambient (predicted in the next 50 and 100 years, respectively [6]). We observed massive impacts on a marine assemblage, with near doubling of growth rates of Antarctic seabed life. Growth increases far exceed those expected from biological temperature relationships established more than 100 years ago by Arrhenius. These increases in growth resulted in a single "r-strategist" pioneer species (the bryozoan Fenestrulina rugula) dominating seabed spatial cover and drove a reduction in overall diversity and evenness. In contrast, a 2°C rise produced divergent responses across species growth, resulting in higher variability in the assemblage. These data extend our ability to expand, integrate, and apply our knowledge of the impact of temperature on biological processes to predict organism, species, and ecosystem level ecological responses to regional warming.
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Affiliation(s)
- Gail V Ashton
- British Antarctic Survey, Natural Environment Research Council, High Cross, Madingley Road, Cambridge CB3 OET, UK; Smithsonian Environmental Research Center, 3150 Paradise Drive, Tiburon, CA 94920, USA.
| | - Simon A Morley
- British Antarctic Survey, Natural Environment Research Council, High Cross, Madingley Road, Cambridge CB3 OET, UK.
| | - David K A Barnes
- British Antarctic Survey, Natural Environment Research Council, High Cross, Madingley Road, Cambridge CB3 OET, UK
| | - Melody S Clark
- British Antarctic Survey, Natural Environment Research Council, High Cross, Madingley Road, Cambridge CB3 OET, UK
| | - Lloyd S Peck
- British Antarctic Survey, Natural Environment Research Council, High Cross, Madingley Road, Cambridge CB3 OET, UK
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167
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Gargallo-Garriga A, Ayala-Roque M, Sardans J, Bartrons M, Granda V, Sigurdsson BD, Leblans NIW, Oravec M, Urban O, Janssens IA, Peñuelas J. Impact of Soil Warming on the Plant Metabolome of Icelandic Grasslands. Metabolites 2017; 7:E44. [PMID: 28832555 PMCID: PMC5618329 DOI: 10.3390/metabo7030044] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Revised: 08/10/2017] [Accepted: 08/18/2017] [Indexed: 11/16/2022] Open
Abstract
Climate change is stronger at high than at temperate and tropical latitudes. The natural geothermal conditions in southern Iceland provide an opportunity to study the impact of warming on plants, because of the geothermal bedrock channels that induce stable gradients of soil temperature. We studied two valleys, one where such gradients have been present for centuries (long-term treatment), and another where new gradients were created in 2008 after a shallow crustal earthquake (short-term treatment). We studied the impact of soil warming (0 to +15 °C) on the foliar metabolomes of two common plant species of high northern latitudes: Agrostis capillaris, a monocotyledon grass; and Ranunculus acris, a dicotyledonous herb, and evaluated the dependence of shifts in their metabolomes on the length of the warming treatment. The two species responded differently to warming, depending on the length of exposure. The grass metabolome clearly shifted at the site of long-term warming, but the herb metabolome did not. The main up-regulated compounds at the highest temperatures at the long-term site were saccharides and amino acids, both involved in heat-shock metabolic pathways. Moreover, some secondary metabolites, such as phenolic acids and terpenes, associated with a wide array of stresses, were also up-regulated. Most current climatic models predict an increase in annual average temperature between 2-8 °C over land masses in the Arctic towards the end of this century. The metabolomes of A. capillaris and R. acris shifted abruptly and nonlinearly to soil warming >5 °C above the control temperature for the coming decades. These results thus suggest that a slight warming increase may not imply substantial changes in plant function, but if the temperature rises more than 5 °C, warming may end up triggering metabolic pathways associated with heat stress in some plant species currently dominant in this region.
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Affiliation(s)
- Albert Gargallo-Garriga
- Consejo Superior de Investigaciones Científicas (CSIC), Global Ecology Unit CREAF-CSIC-UAB, 08193 Bellaterra, Spain.
- Ecological and Forestry Applications Research Centre, 08193 Cerdanyola del Vallès, Spain.
| | - Marta Ayala-Roque
- Consejo Superior de Investigaciones Científicas (CSIC), Global Ecology Unit CREAF-CSIC-UAB, 08193 Bellaterra, Spain.
- Ecological and Forestry Applications Research Centre, 08193 Cerdanyola del Vallès, Spain.
| | - Jordi Sardans
- Consejo Superior de Investigaciones Científicas (CSIC), Global Ecology Unit CREAF-CSIC-UAB, 08193 Bellaterra, Spain.
- Ecological and Forestry Applications Research Centre, 08193 Cerdanyola del Vallès, Spain.
| | - Mireia Bartrons
- Consejo Superior de Investigaciones Científicas (CSIC), Global Ecology Unit CREAF-CSIC-UAB, 08193 Bellaterra, Spain.
- BETA Technological Centre (Tecnio), Aquatic Ecology Group, University of Vic-Central University of Catalonia, Vic, 08500 Barcelona, Spain.
| | - Victor Granda
- Consejo Superior de Investigaciones Científicas (CSIC), Global Ecology Unit CREAF-CSIC-UAB, 08193 Bellaterra, Spain.
- Ecological and Forestry Applications Research Centre, 08193 Cerdanyola del Vallès, Spain.
| | | | - Niki I W Leblans
- Agricultural University of Iceland, IS-311 Borgarnes, Iceland.
- Department of Biology, University of Antwerp, BE-2610 Antwerp, Belgium.
| | - Michal Oravec
- Global Change Research Institute, The Czech Academy of Sciences, Belidla 986/4a, CZ-60300 Brno, Czech Republic.
| | - Otmar Urban
- Global Change Research Institute, The Czech Academy of Sciences, Belidla 986/4a, CZ-60300 Brno, Czech Republic.
| | - Ivan A Janssens
- Department of Biology, University of Antwerp, BE-2610 Antwerp, Belgium.
| | - Josep Peñuelas
- Consejo Superior de Investigaciones Científicas (CSIC), Global Ecology Unit CREAF-CSIC-UAB, 08193 Bellaterra, Spain.
- Ecological and Forestry Applications Research Centre, 08193 Cerdanyola del Vallès, Spain.
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168
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Camac JS, Williams RJ, Wahren CH, Hoffmann AA, Vesk PA. Climatic warming strengthens a positive feedback between alpine shrubs and fire. GLOBAL CHANGE BIOLOGY 2017; 23:3249-3258. [PMID: 28063181 DOI: 10.1111/gcb.13614] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Accepted: 12/12/2016] [Indexed: 05/23/2023]
Abstract
Climate change is expected to increase fire activity and woody plant encroachment in arctic and alpine landscapes. However, the extent to which these increases interact to affect the structure, function and composition of alpine ecosystems is largely unknown. Here we use field surveys and experimental manipulations to examine how warming and fire affect recruitment, seedling growth and seedling survival in four dominant Australian alpine shrubs. We found that fire increased establishment of shrub seedlings by as much as 33-fold. Experimental warming also doubled growth rates of tall shrub seedlings and could potentially increase their survival. By contrast, warming had no effect on shrub recruitment, postfire tussock regeneration, or how tussock grass affected shrub seedling growth and survival. These findings indicate that warming, coupled with more frequent or severe fires, will likely result in an increase in the cover and abundance of evergreen shrubs. Given that shrubs are one of the most flammable components in alpine and tundra environments, warming is likely to strengthen an existing feedback between woody species abundance and fire in these ecosystems.
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Affiliation(s)
- James S Camac
- The Centre of Excellence for Environmental Decisions, School of BioSciences, The University of Melbourne, Parkville, Vic., 3010, Australia
- Research Centre for Applied Alpine Ecology, La Trobe University, Melbourne, Vic., 3086, Australia
| | - Richard J Williams
- Research Centre for Applied Alpine Ecology, La Trobe University, Melbourne, Vic., 3086, Australia
- Research Institute for the Environment and Livelihoods, Charles Darwin University, Darwin, NT, 0909, Australia
| | - Carl-Henrik Wahren
- Research Centre for Applied Alpine Ecology, La Trobe University, Melbourne, Vic., 3086, Australia
| | - Ary A Hoffmann
- Research Centre for Applied Alpine Ecology, La Trobe University, Melbourne, Vic., 3086, Australia
- Bio21 Institute, School of BioSciences, The University of Melbourne, Melbourne, Vic., 3010, Australia
| | - Peter A Vesk
- The Centre of Excellence for Environmental Decisions, School of BioSciences, The University of Melbourne, Parkville, Vic., 3010, Australia
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169
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Muller AL, Hardy SP, Mamet SD, Ota M, Lamb EG, Siciliano SD. Salix arctica
changes root distribution and nutrient uptake in response to subsurface nutrients in High Arctic deserts. Ecology 2017; 98:2158-2169. [DOI: 10.1002/ecy.1908] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Accepted: 05/10/2017] [Indexed: 11/06/2022]
Affiliation(s)
- Amanda L. Muller
- Department of Soil Science; University of Saskatchewan; Saskatoon Saskatchewan S7N 5A8 Canada
| | - Sarah P. Hardy
- Department of Soil Science; University of Saskatchewan; Saskatoon Saskatchewan S7N 5A8 Canada
| | - Steven D. Mamet
- Department of Soil Science; University of Saskatchewan; Saskatoon Saskatchewan S7N 5A8 Canada
| | - Mitsuaki Ota
- Department of Soil Science; University of Saskatchewan; Saskatoon Saskatchewan S7N 5A8 Canada
| | - Eric G. Lamb
- Department of Plant Sciences; University of Saskatchewan; Saskatoon Saskatchewan S7N 5A8 Canada
| | - Steven D. Siciliano
- Department of Soil Science; University of Saskatchewan; Saskatoon Saskatchewan S7N 5A8 Canada
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170
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Carey JC, Parker TC, Fetcher N, Tang J. Biogenic silica accumulation varies across tussock tundra plant functional type. Funct Ecol 2017. [DOI: 10.1111/1365-2435.12912] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Joanna C. Carey
- Division of Math and ScienceBabson College Babson Park MA USA
- The Ecosystem CenterMarine Biological Laboratory Woods Hole MA USA
| | - Thomas C. Parker
- The Ecosystem CenterMarine Biological Laboratory Woods Hole MA USA
| | - Ned Fetcher
- Institute for Environmental Science and SustainabilityWilkes University Wilkes‐Barre PA USA
| | - Jianwu Tang
- The Ecosystem CenterMarine Biological Laboratory Woods Hole MA USA
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171
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Prevéy J, Vellend M, Rüger N, Hollister RD, Bjorkman AD, Myers-Smith IH, Elmendorf SC, Clark K, Cooper EJ, Elberling B, Fosaa AM, Henry GHR, Høye TT, Jónsdóttir IS, Klanderud K, Lévesque E, Mauritz M, Molau U, Natali SM, Oberbauer SF, Panchen ZA, Post E, Rumpf SB, Schmidt NM, Schuur EAG, Semenchuk PR, Troxler T, Welker JM, Rixen C. Greater temperature sensitivity of plant phenology at colder sites: implications for convergence across northern latitudes. GLOBAL CHANGE BIOLOGY 2017; 23:2660-2671. [PMID: 28079308 DOI: 10.1111/gcb.13619] [Citation(s) in RCA: 82] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Revised: 11/30/2016] [Accepted: 12/03/2016] [Indexed: 05/12/2023]
Abstract
Warmer temperatures are accelerating the phenology of organisms around the world. Temperature sensitivity of phenology might be greater in colder, higher latitude sites than in warmer regions, in part because small changes in temperature constitute greater relative changes in thermal balance at colder sites. To test this hypothesis, we examined up to 20 years of phenology data for 47 tundra plant species at 18 high-latitude sites along a climatic gradient. Across all species, the timing of leaf emergence and flowering was more sensitive to a given increase in summer temperature at colder than warmer high-latitude locations. A similar pattern was seen over time for the flowering phenology of a widespread species, Cassiope tetragona. These are among the first results highlighting differential phenological responses of plants across a climatic gradient and suggest the possibility of convergence in flowering times and therefore an increase in gene flow across latitudes as the climate warms.
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Affiliation(s)
- Janet Prevéy
- WSL Institute for Snow and Avalanche Research SLF, 7260 Davos, Switzerland
- USDA-Forest Service, Pacific Northwest Research Station, Olympia, WA 98512, USA
| | - Mark Vellend
- Département de Biologie, Université de Sherbrooke, Sherbrooke, QC J1K 2R1, Canada
| | - Nadja Rüger
- German Centre for Integrative Biodiversity Research (iDiv), 04103 Leipzig, Germany
- Smithsonian Tropical Research Institute, Balboa Ancón, Panama, Republic of Panama
| | - Robert D Hollister
- Biology Department, Grand Valley State University, Allendale, MI 49041, USA
| | - Anne D Bjorkman
- German Centre for Integrative Biodiversity Research (iDiv), 04103 Leipzig, Germany
- School of Geosciences, University of Edinburgh, Edinburgh, UK
| | | | | | - Karin Clark
- Environment and Natural Resources, Government of the Northwest Territories, NT X1A 3S8, Canada
| | - Elisabeth J Cooper
- Institute for Arctic and Marine Biology, UiT-The Arctic University of Norway, 9037 Tromsø, Norway
| | - Bo Elberling
- Center for Permafrost (CENPERM), Department of Geosciences and Natural Resource Management, University of Copenhagen, DK-1350 Copenhagen, Denmark
| | - Anna M Fosaa
- Faroese Museum of Natural History, Hoyvík 188, Faroe Islands
| | - Gregory H R Henry
- Department of Geography and Biodiversity Research Institute, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Toke T Høye
- Arctic Research Center, Department of Bioscience, Aarhus University, DK-8000 Aarhus, Denmark
| | - Ingibjörg S Jónsdóttir
- The University Centre in Svalbard, N-9171 Longyearbyen, Norway
- Faculty of Life and Environmental Sciences, University of Iceland, 101 Reykjavík, Iceland
| | - Kari Klanderud
- Department of Ecology and Natural Resources, Norwegian University of Life Sciences, NO-1432, Ås, Norway
| | - Esther Lévesque
- Université du Québec à Trois-Rivières, Trois-Rivières, QC G9A 5H7, Canada
| | - Marguerite Mauritz
- Center for Ecosystem Science and Society Center, Northern Arizona University, Flagstaff, AZ 86011, USA
| | - Ulf Molau
- Department of Biology and Environmental Sciences, University of Gothenburg, S-405 30 Gothenburg, Sweden
| | | | - Steven F Oberbauer
- Department of Biological Sciences, Florida International University, Miami, FL 33181, USA
| | - Zoe A Panchen
- Department of Biology, Carleton University, Ottawa, ON K1S 5B6, Canada
| | - Eric Post
- Department of Wildlife, Fish, & Conservation Biology, University of California, Davis, CA 95616, USA
| | - Sabine B Rumpf
- Department of Botany and Biodiversity Research, University of Vienna, A-1030 Vienna, Austria
| | - Niels M Schmidt
- Arctic Research Center, Department of Bioscience, Aarhus University, DK-8000 Aarhus, Denmark
| | - Edward A G Schuur
- Center for Ecosystem Science and Society Center, Northern Arizona University, Flagstaff, AZ 86011, USA
| | - Phillip R Semenchuk
- Institute for Arctic and Marine Biology, UiT-The Arctic University of Norway, 9037 Tromsø, Norway
| | | | - Jeffrey M Welker
- Department of Biological Sciences, University of Alaska, Anchorage, AK 99508, USA
| | - Christian Rixen
- WSL Institute for Snow and Avalanche Research SLF, 7260 Davos, Switzerland
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172
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Veen GFC, De Long JR, Kardol P, Sundqvist MK, Snoek LB, Wardle DA. Coordinated responses of soil communities to elevation in three subarctic vegetation types. OIKOS 2017. [DOI: 10.1111/oik.04158] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- G. F. Ciska Veen
- Dept of Forest Ecology and Management, Swedish Univ. of Agricultural Sciences; Umeå Sweden
| | - Jonathan R. De Long
- Dept of Forest Ecology and Management, Swedish Univ. of Agricultural Sciences; Umeå Sweden
- School of Earth and Environmental Sciences, The Univ. of Manchester; Manchester England
| | - Paul Kardol
- Dept of Forest Ecology and Management, Swedish Univ. of Agricultural Sciences; Umeå Sweden
| | - Maja K. Sundqvist
- Dept of Ecology and Environmental Science, Umeå Univ.; Umeå Sweden
- Center for Macroecology, Evolution and Climate, Natural History Museum of Denmark, Univ. of Copenhagen; Copenhagen Denmark
| | - L. Basten Snoek
- Dept of Terrestrial Ecology, Netherlands Inst. of Ecology PO Box 50; NL-6700 AB, Wageningen Netherlands
- Laboratory of Nematology, Wageningen Univ.; Wageningen Netherlands
| | - David A. Wardle
- Dept of Forest Ecology and Management, Swedish Univ. of Agricultural Sciences; Umeå Sweden
- Asian School of the Environment, Nanyang Technological Univ.; Singapore
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173
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Vanneste T, Michelsen O, Graae BJ, Kyrkjeeide MO, Holien H, Hassel K, Lindmo S, Kapás RE, De Frenne P. Impact of climate change on alpine vegetation of mountain summits in Norway. Ecol Res 2017. [DOI: 10.1007/s11284-017-1472-1] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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174
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Wellstein C, Poschlod P, Gohlke A, Chelli S, Campetella G, Rosbakh S, Canullo R, Kreyling J, Jentsch A, Beierkuhnlein C. Effects of extreme drought on specific leaf area of grassland species: A meta-analysis of experimental studies in temperate and sub-Mediterranean systems. GLOBAL CHANGE BIOLOGY 2017; 23:2473-2481. [PMID: 28208238 DOI: 10.1111/gcb.13662] [Citation(s) in RCA: 87] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Revised: 11/18/2016] [Accepted: 01/14/2017] [Indexed: 05/06/2023]
Abstract
Here, we conducted a meta-analysis of experimental drought manipulation studies using rainout shelters in five sites of natural grassland ecosystems of Europe. The single studies assess the effects of extreme drought on the intraspecific variation of the specific leaf area (SLA), a proxy of plant growth. We evaluate and compare the effect size of the SLA response for the functional groups of forbs and grasses in temperate and sub-Mediterranean systems. We hypothesized that the functional groups of grasses and forbs from temperate grassland systems have different strategies in short-term drought response, measured as adjustment of SLA, with SLA-reduction in grasses and SLA-maintenance in forbs. Second, we hypothesized that grasses and forbs from sub-Mediterranean systems do not differ in their drought response as both groups maintain their SLA. We found a significant decrease of SLA in grasses of the temperate systems in response to drought while SLA of forbs showed no significant response. Lower SLA is associated with enhanced water-use efficiency under water stress and thus can be seen as a strategy of phenotypic adjustment. By contrast, in the sub-Mediterranean systems, grasses significantly increased their SLA in the drought treatment. This result points towards a better growth performance of these grasses, which is most likely related to their strategy to allocate resources to belowground parts. The observed SLA reduction of forbs is most likely a direct drought response given that competitive effect of grasses is unlikely due to the scanty vegetation cover. We point out that phenotypic adjustment is an important driver of short-term functional plant response to climatic extremes such as drought. Differential reactions of functional groups have to be interpreted against the background of the group's evolutionary configuration that can differ between climatic zones.
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Affiliation(s)
- Camilla Wellstein
- Faculty of Science and Technology, Free University of Bozen-Bolzano, Bolzano, Italy
| | - Peter Poschlod
- Ecology and Conservation Biology, Institute of Plant Sciences, University of Regensburg, Regensburg, Germany
| | | | - Stefano Chelli
- School of Biosciences and Veterinary Medicine, Plant Diversity and Ecosystems Management Unit, University of Camerino, Camerino, Italy
| | - Giandiego Campetella
- School of Biosciences and Veterinary Medicine, Plant Diversity and Ecosystems Management Unit, University of Camerino, Camerino, Italy
| | - Sergey Rosbakh
- Ecology and Conservation Biology, Institute of Plant Sciences, University of Regensburg, Regensburg, Germany
| | - Roberto Canullo
- School of Biosciences and Veterinary Medicine, Plant Diversity and Ecosystems Management Unit, University of Camerino, Camerino, Italy
| | - Jürgen Kreyling
- Experimental Plant Ecology, Institute of Botany and Landscape Ecology, Greifswald University, Greifswald, Germany
| | - Anke Jentsch
- Disturbance Ecology, University of Bayreuth, Bayreuth, Germany
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175
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Saccone P, Hoikka K, Virtanen R. What if plant functional types conceal species-specific responses to environment? Study on arctic shrub communities. Ecology 2017; 98:1600-1612. [DOI: 10.1002/ecy.1817] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Revised: 02/02/2017] [Accepted: 03/06/2017] [Indexed: 11/06/2022]
Affiliation(s)
- Patrick Saccone
- Department of Ecology and Genetics; University of Oulu; P.O. Box 3000 FI-90014 Oulu Finland
| | | | - Risto Virtanen
- Department of Ecology and Genetics; University of Oulu; P.O. Box 3000 FI-90014 Oulu Finland
- Department of Physiological Diversity; Helmholtz Center for Environmental Research - UFZ; Permoserstrasse 15 04318 Leipzig Germany
- German Center for Integrative Biodiversity Research (iDiv); Deutscher Platz 5a 04103 Leipzig Germany
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176
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Zhang H, Yang X, Wang J, Wang GG, Yu M, Wu T. Leaf N and P stoichiometry in relation to leaf shape and plant size for Quercus acutissima provenances across China. Sci Rep 2017; 7:46133. [PMID: 28393848 PMCID: PMC5385868 DOI: 10.1038/srep46133] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Accepted: 03/13/2017] [Indexed: 11/29/2022] Open
Abstract
Plant stoichiometry in relation to the structure and function of biological systems has been investigated at multiple scales. However, few studies have focused on the roles of stoichiometry for a given species. In this study, we determined leaf N and P stoichiometry, leaf shape and plant size in three Quercus acutissima common gardens with different climatic and site conditions. In the three common gardens, leaf N and P stoichiometry was significantly correlated with leaf shape and plant size, suggesting that leaf N and P stoichiometry affects the morphological performance of the leaves and stem. The scaling slopes of the relationships between leaf N and P stoichiometry and leaf shape ranged from |0.12| to |1.00|, while the slopes of the relationships between leaf N and P stoichiometry and plant size ranged from |0.95| to |2.66|. These results suggest that non-functional tissues (stem) are more susceptible to leaf nutrition than functional tissues (leaves), and leaf stoichiometry is more important in the construction of non-functional tissues (stem). Between the northernmost and southernmost common gardens, leaf N and leaf width (W), N:P and stem height (H), and N:P and stem diameter (D) showed significant covariations, which indicates that leaf N and W, N:P and plant size exhibit similar plastic responses to environmental change.
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Affiliation(s)
- Hui Zhang
- East China Coastal Forest Ecosystem Long-term Research Station, Research Institute of Subtropical Forestry, Chinese Academy of Forestry, Fuyang, Zhejiang 311400, PR China
- Forestry College, Shanxi Agriculture University, Taigu, Shanxi 030801, PR China
| | - Xiuqing Yang
- Forestry College, Shanxi Agriculture University, Taigu, Shanxi 030801, PR China
| | - Jingyuan Wang
- East China Coastal Forest Ecosystem Long-term Research Station, Research Institute of Subtropical Forestry, Chinese Academy of Forestry, Fuyang, Zhejiang 311400, PR China
| | - G. Geoff Wang
- Department of Forestry and Environmental Conservation, Clemson University, Clemson, SC 29634-0317, USA
| | - Mukui Yu
- East China Coastal Forest Ecosystem Long-term Research Station, Research Institute of Subtropical Forestry, Chinese Academy of Forestry, Fuyang, Zhejiang 311400, PR China
| | - Tonggui Wu
- East China Coastal Forest Ecosystem Long-term Research Station, Research Institute of Subtropical Forestry, Chinese Academy of Forestry, Fuyang, Zhejiang 311400, PR China
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177
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McLaren JR, Buckeridge KM, Weg MJ, Shaver GR, Schimel JP, Gough L. Shrub encroachment in Arctic tundra:
Betula nana
effects on above‐ and belowground litter decomposition. Ecology 2017; 98:1361-1376. [DOI: 10.1002/ecy.1790] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Revised: 01/16/2017] [Accepted: 02/16/2017] [Indexed: 11/10/2022]
Affiliation(s)
- Jennie R. McLaren
- Department of Biological Sciences University of Texas at El Paso El Paso Texas 79968 USA
| | | | - Martine J. Weg
- The Ecosystems Center Marine Biological Laboratory Woods Hole Massachusetts 02543 USA
| | - Gaius R. Shaver
- The Ecosystems Center Marine Biological Laboratory Woods Hole Massachusetts 02543 USA
| | - Joshua P. Schimel
- Department of Ecology, Evolution and Marine Biology University of California Santa Barbara Santa Barbara California 93106 USA
| | - Laura Gough
- Department of Biological Sciences Towson University Towson Maryland 21252 USA
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178
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Clare DS, Spencer M, Robinson LA, Frid CLJ. Explaining ecological shifts: the roles of temperature and primary production in the long-term dynamics of benthic faunal composition. OIKOS 2017. [DOI: 10.1111/oik.03661] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- David S. Clare
- School of Environmental Sciences, Univ. of Liverpool, Brownlow Street, Liverpool; L69 3GP UK
| | - Matthew Spencer
- School of Environmental Sciences, Univ. of Liverpool, Brownlow Street, Liverpool; L69 3GP UK
| | - Leonie A. Robinson
- School of Environmental Sciences, Univ. of Liverpool, Brownlow Street, Liverpool; L69 3GP UK
| | - Christopher L. J. Frid
- School of Environmental Sciences, Univ. of Liverpool, Brownlow Street, Liverpool; L69 3GP UK
- Griffith School of Environment, Griffith Univ.; Southport QLD Australia
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179
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Andresen CG, Lara MJ, Tweedie CE, Lougheed VL. Rising plant-mediated methane emissions from arctic wetlands. GLOBAL CHANGE BIOLOGY 2017; 23:1128-1139. [PMID: 27541438 DOI: 10.1111/gcb.13469] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Accepted: 07/15/2016] [Indexed: 06/06/2023]
Abstract
Plant-mediated CH4 flux is an important pathway for land-atmosphere CH4 emissions, but the magnitude, timing, and environmental controls, spanning scales of space and time, remain poorly understood in arctic tundra wetlands, particularly under the long-term effects of climate change. CH4 fluxes were measured in situ during peak growing season for the dominant aquatic emergent plants in the Alaskan arctic coastal plain, Carex aquatilis and Arctophila fulva, to assess the magnitude and species-specific controls on CH4 flux. Plant biomass was a strong predictor of A. fulva CH4 flux while water depth and thaw depth were copredictors for C. aquatilis CH4 flux. We used plant and environmental data from 1971 to 1972 from the historic International Biological Program (IBP) research site near Barrow, Alaska, which we resampled in 2010-2013, to quantify changes in plant biomass and thaw depth, and used these to estimate species-specific decadal-scale changes in CH4 fluxes. A ~60% increase in CH4 flux was estimated from the observed plant biomass and thaw depth increases in tundra ponds over the past 40 years. Despite covering only ~5% of the landscape, we estimate that aquatic C. aquatilis and A. fulva account for two-thirds of the total regional CH4 flux of the Barrow Peninsula. The regionally observed increases in plant biomass and active layer thickening over the past 40 years not only have major implications for energy and water balance, but also have significantly altered land-atmosphere CH4 emissions for this region, potentially acting as a positive feedback to climate warming.
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Affiliation(s)
- Christian G Andresen
- Department of Biological Sciences, The University of Texas at El Paso, El Paso, TX, 79968, USA
- Earth and Environmental Science Division, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - Mark J Lara
- Department of Biological Sciences, The University of Texas at El Paso, El Paso, TX, 79968, USA
- Institute of Arctic Biology, University of Alaska, Fairbanks, AK, 99775, USA
| | - Craig E Tweedie
- Department of Biological Sciences, The University of Texas at El Paso, El Paso, TX, 79968, USA
| | - Vanessa L Lougheed
- Department of Biological Sciences, The University of Texas at El Paso, El Paso, TX, 79968, USA
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180
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Meng FD, Jiang LL, Zhang ZH, Cui SJ, Duan JC, Wang SP, Luo CY, Wang Q, Zhou Y, Li XE, Zhang LR, Li BW, Dorji T, Li YN, Du MY. Changes in flowering functional group affect responses of community phenological sequences to temperature change. Ecology 2017; 98:734-740. [PMID: 27984640 DOI: 10.1002/ecy.1685] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2016] [Revised: 11/20/2016] [Accepted: 11/30/2016] [Indexed: 11/08/2022]
Abstract
Our ability to predict how temperature modifies phenology at the community scale is limited by our lack of understanding of responses by functional groups of flowering plants. These responses differ among species with different life histories. We performed a reciprocal transplant experiment along four elevation gradients (e.g., 3,200, 3,400, 3,600 and 3,800 m) to investigate the effects of warming (transferred downward) and cooling (transferred upward) on plant flowering functional groups (FFGs) and community phenological sequences (i.e., seven phenological events). Warming significantly decreased early-spring-flowering (ESF) plant coverage and increased mid-summer-flowering plant (MSF) coverage, while cooling had the opposite effect. All community phenological events were advanced by warming and delayed by cooling except for the date of complete leaf-coloring, which showed the opposite response. Warming and cooling could cause greater advance or delay in early-season phenological events of the community through increased coverage of MSF species, and warming could delay late-season phenological events of the community by increased coverage of ESF species. These results suggested that coverage change of FFGs in the community induced by temperature change could mediate the responses of the community phenological events to temperature change in the future. The response of phenological events to temperature change at the species level may not be sufficient to predict phenological responses at the community-level due to phenological compensation between species in the community.
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Affiliation(s)
- F D Meng
- Key Laboratory of Alpine Ecology and Biodiversity, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, 100101, China
| | - L L Jiang
- Key Laboratory of Alpine Ecology and Biodiversity, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, 100101, China
| | - Z H Zhang
- Key Laboratory of Adaptation and Evolution of Plateau Biota, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining, 810008, China
| | - S J Cui
- Key Laboratory of Alpine Ecology and Biodiversity, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, 100101, China.,CAS Center for Excellence in Tibetan Plateau Earth Science, Chinese Academy of Sciences, Beijing, 100101, China.,Naqu Integrated Observation and Research Station of Ecology and Environment, Tibet University;Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Lhasa, 850012, China.,Graduate University of Chinese Academy of Sciences, Beijing, 100049, China
| | - J C Duan
- Binhai Research Institute in Tianjin, Tianjin, 300457, China
| | - S P Wang
- Key Laboratory of Alpine Ecology and Biodiversity, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, 100101, China.,CAS Center for Excellence in Tibetan Plateau Earth Science, Chinese Academy of Sciences, Beijing, 100101, China.,Naqu Integrated Observation and Research Station of Ecology and Environment, Tibet University;Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Lhasa, 850012, China
| | - C Y Luo
- Key Laboratory of Adaptation and Evolution of Plateau Biota, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining, 810008, China
| | - Q Wang
- Key Laboratory of Alpine Ecology and Biodiversity, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, 100101, China.,Graduate University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Y Zhou
- Key Laboratory of Alpine Ecology and Biodiversity, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, 100101, China.,Graduate University of Chinese Academy of Sciences, Beijing, 100049, China
| | - X E Li
- Key Laboratory of Alpine Ecology and Biodiversity, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, 100101, China
| | - L R Zhang
- Key Laboratory of Alpine Ecology and Biodiversity, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, 100101, China
| | - B W Li
- Key Laboratory of Alpine Ecology and Biodiversity, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, 100101, China.,Graduate University of Chinese Academy of Sciences, Beijing, 100049, China
| | - T Dorji
- Key Laboratory of Alpine Ecology and Biodiversity, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, 100101, China.,CAS Center for Excellence in Tibetan Plateau Earth Science, Chinese Academy of Sciences, Beijing, 100101, China
| | - Y N Li
- Key Laboratory of Adaptation and Evolution of Plateau Biota, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining, 810008, China
| | - M Y Du
- Institute for Agro-Environmental Sciences, NARO, Tsukuba, 305-8604, Japan
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181
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Wang C, Wang G, Wang Y, Zi H, Lerdau M, Liu W. Effects of long-term experimental warming on plant community properties and soil microbial community composition in an alpine meadow. Isr J Ecol Evol 2017. [DOI: 10.1080/15659801.2017.1281201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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182
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Nicholson AE, Wilkinson DM, Williams HT, Lenton TM. Multiple states of environmental regulation in well-mixed model biospheres. J Theor Biol 2017; 414:17-34. [DOI: 10.1016/j.jtbi.2016.11.019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Revised: 10/27/2016] [Accepted: 11/21/2016] [Indexed: 11/16/2022]
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183
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Westergaard-Nielsen A, Lund M, Pedersen SH, Schmidt NM, Klosterman S, Abermann J, Hansen BU. Transitions in high-Arctic vegetation growth patterns and ecosystem productivity tracked with automated cameras from 2000 to 2013. AMBIO 2017; 46:39-52. [PMID: 28116683 PMCID: PMC5258658 DOI: 10.1007/s13280-016-0864-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Climate-induced changes in vegetation phenology at northern latitudes are still poorly understood. Continued monitoring and research are therefore needed to improve the understanding of abiotic drivers. Here we used 14 years of time lapse imagery and climate data from high-Arctic Northeast Greenland to assess the seasonal response of a dwarf shrub heath, grassland, and fen, to inter-annual variation in snow-cover, soil moisture, and air and soil temperatures. A late snow melt and start of growing season is counterbalanced by a fast greenup and a tendency to higher peak greenness values. Snow water equivalents and soil moisture explained up to 77 % of growing season duration and senescence phase, highlighting that water availability is a prominent driver in the heath site, rather than temperatures. We found a significant advance in the start of spring by 10 days and in the end of fall by 11 days, resulting in an unchanged growing season length. Vegetation greenness, derived from the imagery, was correlated to primary productivity, showing that the imagery holds valuable information on vegetation productivity.
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Affiliation(s)
- Andreas Westergaard-Nielsen
- Department of Geosciences and Natural Resource Management, University of Copenhagen, Oestervoldgade 10, 1350, Copenhagen, Denmark.
- Center for Permafrost (CENPERM), University of Copenhagen, Oestervoldgade 10, 1350, Copenhagen, Denmark.
| | - Magnus Lund
- Department for Bioscience, Arctic Research Centre, Aarhus University, Frederiksborgvej 399, 4000, Roskilde, Denmark
| | - Stine Højlund Pedersen
- Department for Bioscience, Arctic Research Centre, Aarhus University, Frederiksborgvej 399, 4000, Roskilde, Denmark
| | - Niels Martin Schmidt
- Department for Bioscience, Arctic Research Centre, Aarhus University, Frederiksborgvej 399, 4000, Roskilde, Denmark
| | - Stephen Klosterman
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, 02138, USA
| | - Jakob Abermann
- Greenland Survey, Asiaq, Svend Jungep Aqqutaa 8, 3900, Nuuk, Greenland
| | - Birger Ulf Hansen
- Department of Geosciences and Natural Resource Management, University of Copenhagen, Oestervoldgade 10, 1350, Copenhagen, Denmark
- Center for Permafrost (CENPERM), University of Copenhagen, Oestervoldgade 10, 1350, Copenhagen, Denmark
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184
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Hobbie JE, Shaver GR, Rastetter EB, Cherry JE, Goetz SJ, Guay KC, Gould WA, Kling GW. Ecosystem responses to climate change at a Low Arctic and a High Arctic long-term research site. AMBIO 2017; 46:160-173. [PMID: 28116685 PMCID: PMC5258662 DOI: 10.1007/s13280-016-0870-x] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Long-term measurements of ecological effects of warming are often not statistically significant because of annual variability or signal noise. These are reduced in indicators that filter or reduce the noise around the signal and allow effects of climate warming to emerge. In this way, certain indicators act as medium pass filters integrating the signal over years-to-decades. In the Alaskan Arctic, the 25-year record of warming of air temperature revealed no significant trend, yet environmental and ecological changes prove that warming is affecting the ecosystem. The useful indicators are deep permafrost temperatures, vegetation and shrub biomass, satellite measures of canopy reflectance (NDVI), and chemical measures of soil weathering. In contrast, the 18-year record in the Greenland Arctic revealed an extremely high summer air-warming of 1.3 °C/decade; the cover of some plant species increased while the cover of others decreased. Useful indicators of change are NDVI and the active layer thickness.
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Affiliation(s)
- John E. Hobbie
- Ecosystems Center, Marine Biological Laboratory, Woods Hole, MA 02543 USA
| | - Gaius R. Shaver
- Ecosystems Center, Marine Biological Laboratory, Woods Hole, MA 02543 USA
| | | | - Jessica E. Cherry
- International Arctic Research Center, University of Alaska, Fairbanks, AK 99775 USA
| | | | | | - William A. Gould
- International Institute of Tropical Forestry, Río Piedras, PR 00926 USA
| | - George W. Kling
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109 USA
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185
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Schollert M, Kivimäenpää M, Michelsen A, Blok D, Rinnan R. Leaf anatomy, BVOC emission and CO2 exchange of arctic plants following snow addition and summer warming. ANNALS OF BOTANY 2017; 119:433-445. [PMID: 28064192 PMCID: PMC5314650 DOI: 10.1093/aob/mcw237] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Revised: 08/11/2016] [Accepted: 10/10/2016] [Indexed: 05/22/2023]
Abstract
BACKGROUND AND AIMS Climate change in the Arctic is projected to increase temperature, precipitation and snowfall. This may alter leaf anatomy and gas exchange either directly or indirectly. Our aim was to assess whether increased snow depth and warming modify leaf anatomy and affect biogenic volatile organic compound (BVOC) emissions and CO2 exchange of the widespread arctic shrubs Betula nana and Empetrum nigrum ssp. hermaphroditum METHODS: Measurements were conducted in a full-factorial field experiment in Central West Greenland, with passive summer warming by open-top chambers and snow addition using snow fences. Leaf anatomy was assessed using light microscopy and scanning electron microscopy. BVOC emissions were measured using a dynamic enclosure system and collection of BVOCs into adsorbent cartridges analysed by gas chromatography-mass spectrometry. Carbon dioxide exchange was measured using an infrared gas analyser. KEY RESULTS Despite a later snowmelt and reduced photosynthesis for B. nana especially, no apparent delays in the BVOC emissions were observed in response to snow addition. Only a few effects of the treatments were seen for the BVOC emissions, with sesquiterpenes being the most responsive compound group. Snow addition affected leaf anatomy by increasing the glandular trichome density in B. nana and modifying the mesophyll of E. hermaphroditum The open-top chambers thickened the epidermis of B. nana, while increasing the glandular trichome density and reducing the palisade:spongy mesophyll ratio in E. hermaphroditum CONCLUSIONS: Leaf anatomy was modified by both treatments already after the first winter and we suggest links between leaf anatomy, CO2 exchange and BVOC emissions. While warming is likely to reduce soil moisture, melt water from a deeper snow pack alleviates water stress in the early growing season. The study emphasizes the ecological importance of changes in winter precipitation in the Arctic, which can interact with climate-warming effects.
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Affiliation(s)
- Michelle Schollert
- Terrestrial Ecology Section, Department of Biology, University of Copenhagen, Universitetsparken 15, 2100 Copenhagen Ø, Denmark
- Center for Permafrost (CENPERM), Department of Geosciences and Natural Resource Management, University of Copenhagen, Øster Voldgade 10, 1350 Copenhagen K, Denmark
| | - Minna Kivimäenpää
- Department of Environmental and Biological Sciences, University of Eastern Finland, PO Box 1627, 70211 Kuopio, Finland
| | - Anders Michelsen
- Terrestrial Ecology Section, Department of Biology, University of Copenhagen, Universitetsparken 15, 2100 Copenhagen Ø, Denmark
- Center for Permafrost (CENPERM), Department of Geosciences and Natural Resource Management, University of Copenhagen, Øster Voldgade 10, 1350 Copenhagen K, Denmark
| | - Daan Blok
- Department of Physical Geography and Ecosystem Science, Lund University, Sölvegatan 12, 223 62 Lund, Sweden
| | - Riikka Rinnan
- Terrestrial Ecology Section, Department of Biology, University of Copenhagen, Universitetsparken 15, 2100 Copenhagen Ø, Denmark
- Center for Permafrost (CENPERM), Department of Geosciences and Natural Resource Management, University of Copenhagen, Øster Voldgade 10, 1350 Copenhagen K, Denmark
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186
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Shortlidge EE, Eppley SM, Kohler H, Rosenstiel TN, Zúñiga GE, Casanova-Katny A. Passive warming reduces stress and shifts reproductive effort in the Antarctic moss, Polytrichastrum alpinum. ANNALS OF BOTANY 2017; 119:27-38. [PMID: 27794516 PMCID: PMC5218369 DOI: 10.1093/aob/mcw201] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Revised: 06/15/2016] [Accepted: 08/05/2016] [Indexed: 05/25/2023]
Abstract
BACKGROUND AND AIMS The Western Antarctic Peninsula is one of the most rapidly warming regions on Earth, and many biotic communities inhabiting this dynamic region are responding to these well-documented climatic shifts. Yet some of the most prevalent organisms of terrestrial Antarctica, the mosses, and their responses to warming have been relatively overlooked and understudied. In this research, the impacts of 6 years of passive warming were investigated using open top chambers (OTCs), on moss communities of Fildes Peninsula, King George Island, Antarctica. METHODS The effects of experimental passive warming on the morphology, sexual reproductive effort and stress physiology of a common dioicous Antarctic moss, Polytrichastrum alpinum ,: were tested, gaining the first species-specific mechanistic insight into moss responses to warming in the Antarctic. Additionally community analyses were conducted examining the impact of warming on overall moss percentage cover and sporophyte production in intact Antarctic moss communities. KEY RESULTS Our results show a generally greater percentage moss cover under warming conditions as well as increased gametangia production in P. alpinum Distinct morphological and physiological shifts in P. alpinum were found under passive warming compared with those without warming: warmed mosses reduced investment in cellular stress defences, but invested more towards primary productivity and gametangia development. CONCLUSIONS Taken together, results from this study of mosses under passive warming imply that in ice-free moss-dominated regions, continued climate warming will probably have profound impacts on moss biology and colonization along the Western Antarctic Peninsula. Such findings highlight the fundamental role that mosses will play in influencing the terrestrialization of a warming Antarctica.
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Affiliation(s)
- Erin E Shortlidge
- Department of Biology, Portland State University, Portland, OR 97201, USA
| | - Sarah M Eppley
- Department of Biology and the Center for Life in Extreme Environments, Portland State University, Portland, OR 97207, USA
| | - Hans Kohler
- Department of Chemistry and Biology, University of Santiago, Alameda 3363 Santiago, Chile
| | - Todd N Rosenstiel
- Department of Biology and the Center for Life in Extreme Environments, Portland State University, Portland, OR 97207, USA
| | - Gustavo E Zúñiga
- Department of Chemistry and Biology, University of Santiago, Alameda 3363 Santiago, Chile
| | - Angélica Casanova-Katny
- Department of Chemistry and Biology, University of Santiago, Alameda 3363 Santiago, Chile
- Program in Environmental Studies (NEA), School of Environmental Science, Natural Resources Faculty, Catholic University of Temuco, Rudecindo Ortega 02950, Temuco, Chile
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187
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Eskelinen A, Kaarlejärvi E, Olofsson J. Herbivory and nutrient limitation protect warming tundra from lowland species' invasion and diversity loss. GLOBAL CHANGE BIOLOGY 2017; 23:245-255. [PMID: 27343482 DOI: 10.1111/gcb.13397] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Accepted: 05/27/2016] [Indexed: 06/06/2023]
Abstract
Herbivory and nutrient limitation can increase the resistance of temperature-limited systems to invasions under climate warming. We imported seeds of lowland species to tundra under factorial treatments of warming, fertilization, herbivore exclusion and biomass removal. We show that warming alone had little impact on lowland species, while exclusion of native herbivores and relaxation of nutrient limitation greatly benefitted them. In contrast, warming alone benefitted resident tundra species and increased species richness; however, these were canceled by negative effects of herbivore exclusion and fertilization. Dominance of lowland species was associated with low cover of tundra species and resulted in decreased species richness. Our results highlight the critical role of biotic and abiotic filters unrelated to temperature in protecting tundra under warmer climate. While scarcity of soil nutrients and native herbivores act as important agents of resistance to invasions by lowland species, they concurrently promote overall species coexistence. However, when these biotic and abiotic resistances are relaxed, invasion of lowland species can lead to decreased abundance of resident tundra species and diminished diversity.
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Affiliation(s)
- Anu Eskelinen
- Department of Ecology, University of Oulu, P.O. Box 3000, FI-90014, Oulu, Finland
- Department of Physiological Diversity, Helmholtz Center for Environmental Research-UFZ, Permoserstr. 15, 04318, Leipzig, Germany
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Deutscher Platz 5e, D-04103, Leipzig, Germany
| | - Elina Kaarlejärvi
- Department of Ecology and Environmental Sciences, Umeå University, SE-90187, Umeå, Sweden
- Plant Biology and Nature Management, Vrije Universiteit Brussel, Pleinlaan 2, B-1050, Brussels, Belgium
| | - Johan Olofsson
- Department of Ecology and Environmental Sciences, Umeå University, SE-90187, Umeå, Sweden
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188
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Lesica P, Crone EE. Arctic and boreal plant species decline at their southern range limits in the Rocky Mountains. Ecol Lett 2016; 20:166-174. [DOI: 10.1111/ele.12718] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2016] [Revised: 06/24/2016] [Accepted: 11/15/2016] [Indexed: 11/27/2022]
Affiliation(s)
- Peter Lesica
- Division of Biological Sciences; University of Montana; Missoula MT 59812 USA
- Conservation Biology Research; Missoula MT 59802 USA
| | - Elizabeth E. Crone
- Department of Biology; Tufts University; 163 Packard Ave Medford MA 02155 USA
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189
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Specific arrangements of species dominance can be more influential than evenness in maintaining ecosystem process and function. Sci Rep 2016; 6:39325. [PMID: 27996034 PMCID: PMC5171799 DOI: 10.1038/srep39325] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Accepted: 11/22/2016] [Indexed: 11/10/2022] Open
Abstract
The ecological consequences of species loss are widely studied, but represent an end point of environmental forcing that is not always realised. Changes in species evenness and the rank order of dominant species are more widespread responses to directional forcing. However, despite the repercussions for ecosystem functioning such changes have received little attention. Here, we experimentally assess how the rearrangement of species dominance structure within specific levels of evenness, rather than changes in species richness and composition, affect invertebrate particle reworking and burrow ventilation behaviour - important moderators of microbial-mediated remineralisation processes in benthic environments - and associated levels of sediment nutrient release. We find that the most dominant species exert a disproportionate influence on functioning at low levels of evenness, but that changes in biomass distribution and a change in emphasis in species-environmental interactions become more important in governing system functionality as evenness increases. Our study highlights the need to consider the functional significance of alterations to community attributes, rather than to solely focus on the attainment of particular levels of diversity when safeguarding biodiversity and ecosystems that provide essential services to society.
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190
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Svendsen SH, Lindwall F, Michelsen A, Rinnan R. Biogenic volatile organic compound emissions along a high arctic soil moisture gradient. THE SCIENCE OF THE TOTAL ENVIRONMENT 2016; 573:131-138. [PMID: 27552736 DOI: 10.1016/j.scitotenv.2016.08.100] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Revised: 08/12/2016] [Accepted: 08/15/2016] [Indexed: 06/06/2023]
Abstract
Emissions of biogenic volatile organic compounds (BVOCs) from terrestrial ecosystems are important for the atmospheric chemistry and the formation of secondary organic aerosols, and may therefore influence the climate. Global warming is predicted to change patterns in precipitation and plant species compositions, especially in arctic regions where the temperature increase will be most pronounced. These changes are potentially highly important for the BVOC emissions but studies investigating the effects are lacking. The aim of this study was to investigate the quality and quantity of BVOC emissions from a high arctic soil moisture gradient extending from dry tundra to a wet fen. Ecosystem BVOC emissions were sampled five times in the July-August period using a push-pull enclosure technique, and BVOCs trapped in absorbent cartridges were analyzed using gas chromatography-mass spectrometry. Plant species compositions were estimated using the point intercept method. In order to take into account important underlying ecosystem processes, gross ecosystem production, ecosystem respiration and net ecosystem production were measured in connection with chamber-based BVOC measurements. Highest emissions of BVOCs were found from vegetation communities dominated by Salix arctica and Cassiope tetragona, which had emission profiles dominated by isoprene and monoterpenes, respectively. These results show that emissions of BVOCs are highly dependent on the plant cover supported by the varying soil moisture, suggesting that high arctic BVOC emissions may affect the climate differently if soil water content and plant cover change.
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Affiliation(s)
- Sarah Hagel Svendsen
- Terrestrial Ecology Section, Department of Biology, University of Copenhagen, Universitetsparken 15, DK -2100 Copenhagen E, Denmark; Center for Permafrost (CENPERM), Department of Geoscience and Natural Resource Management, University of Copenhagen, Øster Voldgade 10, DK -1350 Copenhagen K, Denmark
| | - Frida Lindwall
- Terrestrial Ecology Section, Department of Biology, University of Copenhagen, Universitetsparken 15, DK -2100 Copenhagen E, Denmark; Center for Permafrost (CENPERM), Department of Geoscience and Natural Resource Management, University of Copenhagen, Øster Voldgade 10, DK -1350 Copenhagen K, Denmark
| | - Anders Michelsen
- Terrestrial Ecology Section, Department of Biology, University of Copenhagen, Universitetsparken 15, DK -2100 Copenhagen E, Denmark; Center for Permafrost (CENPERM), Department of Geoscience and Natural Resource Management, University of Copenhagen, Øster Voldgade 10, DK -1350 Copenhagen K, Denmark
| | - Riikka Rinnan
- Terrestrial Ecology Section, Department of Biology, University of Copenhagen, Universitetsparken 15, DK -2100 Copenhagen E, Denmark; Center for Permafrost (CENPERM), Department of Geoscience and Natural Resource Management, University of Copenhagen, Øster Voldgade 10, DK -1350 Copenhagen K, Denmark.
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191
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Hedwall PO, Brunet J. Trait variations of ground flora species disentangle the effects of global change and altered land-use in Swedish forests during 20 years. GLOBAL CHANGE BIOLOGY 2016; 22:4038-4047. [PMID: 27111238 DOI: 10.1111/gcb.13329] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Revised: 04/07/2016] [Accepted: 04/17/2016] [Indexed: 05/22/2023]
Abstract
Northern forest ecosystems are exposed to a range of anthropogenic processes including global warming, atmospheric deposition, and changing land-use. The vegetation of northern forests is composed of species with several functional traits related to these processes, whose effects may be difficult to disentangle. Here, we combined analyses of spatio-temporal dynamics and functional traits of ground flora species, including morphological characteristics, responses to macro- and microclimate, soil conditions, and disturbance. Based on data from the Swedish National Forest Inventory, we compared changes in occurrence of a large number of ground flora species during a 20-year period (1994-2013) in boreal and temperate Sweden respectively. Our results show that a majority of the common ground flora species have changed their overall frequency. Comparisons of functional traits between increasing and declining species, and of trends in mean trait values of sample plots, indicate that current floristic changes are caused by combined effects of climate warming, nitrogen deposition and changing land-use. Changes and their relations with plant traits were generally larger in temperate southern Sweden. Nutrient-demanding species with mesotrophic morphology were favored by ongoing eutrophication due to nitrogen deposition in the temperate zone, while dwarf shrubs with low demands on nitrogen decreased in frequency. An increase of species with less northern and less eastern distribution limits was also restricted to temperate Sweden, and indicates effects of a moister and milder macroclimate. A trend toward dense plantation forests is mirrored by a decrease of light-demanding species in both vegetation zones, and a decrease of grassland species in the temperate zone. Although denser tree canopies may buffer effects of a warmer climate and of nitrogen deposition to some extent, traits related to these processes were weakly correlated in the group of species with changing frequency. Hence, our results indicate specific effects of these often confounded anthropogenic processes.
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Affiliation(s)
- Per-Ola Hedwall
- Southern Swedish Forest Research Centre, Swedish University of Agricultural Sciences, Box 49, 230 53, Alnarp, Sweden
| | - Jörg Brunet
- Southern Swedish Forest Research Centre, Swedish University of Agricultural Sciences, Box 49, 230 53, Alnarp, Sweden
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192
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Penton CR, Yang C, Wu L, Wang Q, Zhang J, Liu F, Qin Y, Deng Y, Hemme CL, Zheng T, Schuur EAG, Tiedje J, Zhou J. NifH-Harboring Bacterial Community Composition across an Alaskan Permafrost Thaw Gradient. Front Microbiol 2016; 7:1894. [PMID: 27933054 PMCID: PMC5121533 DOI: 10.3389/fmicb.2016.01894] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Accepted: 11/11/2016] [Indexed: 11/13/2022] Open
Abstract
Since nitrogen (N) is often limiting in permafrost soils, we investigated the N2-fixing genetic potential and the inferred taxa harboring those genes by sequencing nifH gene fragments in samples taken along a permafrost thaw gradient in an Alaskan boreal soil. Samples from minimally, moderately and extensively thawed sites were taken to a depth of 79 cm to encompass zones above and below the depth of the water table. NifH reads were translated with frameshift correction and 112,476 sequences were clustered at 5% amino acid dissimilarity resulting in 1,631 OTUs. Sample depth in relation to water table depth was correlated to differences in the NifH sequence classes with those most closely related to group I nifH-harboring Alpha- and Beta-Proteobacteria in higher abundance above water table depth while those related to group III nifH-harboring Delta Proteobacteria more abundant below. The most dominant below water table depth NifH sequences, comprising 1/3 of the total, were distantly related to Verrucomicrobia-Opitutaceae. Overall, these results suggest that permafrost thaw alters the class-level composition of N2-fixing communities in the thawed soil layers and that this distinction corresponds to the depth of the water table. These nifH data were also compared to nifH sequences obtained from a study at an Alaskan taiga site, and to those of other geographically distant, non-permafrost sites. The two Alaska sites were differentiated largely by changes in relative abundances of the same OTUs, whereas the non-Alaska sites were differentiated by the lack of many Alaskan OTUs, and the presence of unique halophilic, sulfate- and iron-reducing taxa in the Alaska sites.
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Affiliation(s)
- C. Ryan Penton
- College of Integrative Sciences and Arts, Arizona State UniversityMesa, AZ, USA
- Arizona State University, Center for Fundamental and Applied Microbiomics, Biodesign InstituteTempe, AZ, USA
| | - Caiyun Yang
- Department of Microbiology and Plant Biology, Institute for Environmental Genomics, University of OklahomaNorman, OK, USA
- Key Lab of the Ministry of Education for Coastal and Wetland Ecosystems, School of Environmental Sciences, Xiamen UniversityXiamen, China
| | - Liyou Wu
- Department of Microbiology and Plant Biology, Institute for Environmental Genomics, University of OklahomaNorman, OK, USA
| | - Qiong Wang
- Center for Microbial Ecology, Michigan State UniversityEast Lansing, MI, USA
| | - Jin Zhang
- Department of Microbiology and Plant Biology, Institute for Environmental Genomics, University of OklahomaNorman, OK, USA
| | - Feifei Liu
- Department of Microbiology and Plant Biology, Institute for Environmental Genomics, University of OklahomaNorman, OK, USA
| | - Yujia Qin
- Department of Microbiology and Plant Biology, Institute for Environmental Genomics, University of OklahomaNorman, OK, USA
| | - Ye Deng
- Department of Microbiology and Plant Biology, Institute for Environmental Genomics, University of OklahomaNorman, OK, USA
| | - Christopher L. Hemme
- Department of Microbiology and Plant Biology, Institute for Environmental Genomics, University of OklahomaNorman, OK, USA
| | - Tianling Zheng
- Key Lab of the Ministry of Education for Coastal and Wetland Ecosystems, School of Environmental Sciences, Xiamen UniversityXiamen, China
| | - Edward A. G. Schuur
- Department of Biological Sciences, Northern Arizona UniversityFlagstaff, AZ, USA
| | - James Tiedje
- Center for Microbial Ecology, Michigan State UniversityEast Lansing, MI, USA
| | - Jizhong Zhou
- Department of Microbiology and Plant Biology, Institute for Environmental Genomics, University of OklahomaNorman, OK, USA
- Earth Sciences Division, Lawrence Berkeley National LaboratoryBerkeley, CA, USA
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua UniversityBeijing, China
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193
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When Winners Become Losers: Predicted Nonlinear Responses of Arctic Birds to Increasing Woody Vegetation. PLoS One 2016; 11:e0164755. [PMID: 27851768 PMCID: PMC5112980 DOI: 10.1371/journal.pone.0164755] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Accepted: 10/02/2016] [Indexed: 11/19/2022] Open
Abstract
Climate change is facilitating rapid changes in the composition and distribution of vegetation at northern latitudes, raising questions about the responses of wildlife that rely on arctic ecosystems. One widely observed change occurring in arctic tundra ecosystems is an increasing dominance of deciduous shrub vegetation. Our goals were to examine the tolerance of arctic-nesting bird species to existing gradients of vegetation along the boreal forest-tundra ecotone, to predict the abundance of species across different heights and densities of shrubs, and to identify species that will be most or least responsive to ongoing expansion of shrubs in tundra ecosystems. We conducted 1,208 point counts on 12 study blocks from 2012–2014 in northwestern Alaska, using repeated surveys to account for imperfect detection of birds. We considered the importance of shrub height, density of low and tall shrubs (i.e. shrubs >0.5 m tall), percent of ground cover attributed to shrubs (including dwarf shrubs <0.5 m tall), and percent of herbaceous plant cover in predicting bird abundance. Among 17 species considered, only gray-cheeked thrush (Catharus minimus) abundance was associated with the highest values of all shrub metrics in its top predictive model. All other species either declined in abundance in response to one or more shrub metrics or reached a threshold where further increases in shrubs did not contribute to greater abundance. In many instances the relationship between avian abundance and shrubs was nonlinear, with predicted abundance peaking at moderate values of the covariate, then declining at high values. In particular, a large number of species were responsive to increasing values of average shrub height with six species having highest abundance at near-zero values of shrub height and abundance of four other species decreasing once heights reached moderate values (≤ 33 cm). Our findings suggest that increases in shrub cover and density will negatively affect abundance of only a few bird species and may potentially be beneficial for many others. As shrub height increases further, however, a considerable number of tundra bird species will likely find habitat increasingly unsuitable.
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194
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Williamson SN, Barrio IC, Hik DS, Gamon JA. Phenology and species determine growing-season albedo increase at the altitudinal limit of shrub growth in the sub-Arctic. GLOBAL CHANGE BIOLOGY 2016; 22:3621-3631. [PMID: 27158930 DOI: 10.1111/gcb.13297] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Revised: 03/02/2016] [Accepted: 03/18/2016] [Indexed: 06/05/2023]
Abstract
Arctic warming is resulting in reduced snow cover and increased shrub growth, both of which have been associated with altered land surface-atmospheric feedback processes involving sensible heat flux, ground heat flux and biogeochemical cycling. Using field measurements, we show that two common Arctic shrub species (Betula glandulosa and Salix pulchra), which are largely responsible for shrub encroachment in tundra, differed markedly in albedo and that albedo of both species increased as growing season progressed when measured at their altitudinal limit. A moveable apparatus was used to repeatedly measure albedo at six precise spots during the summer of 2012, and resampled in 2013. Contrary to the generally accepted view of shrub-covered areas having low albedo in tundra, full-canopy prostrate B. glandulosa had almost the highest albedo of all surfaces measured during the peak of the growing season. The higher midsummer albedo is also evident in localized MODIS albedo aggregated from 2000 to 2013, which displays a similar increase in growing-season albedo. Using our field measurements, we show the ensemble summer increase in tundra albedo counteracts the generalized effect of earlier spring snow melt on surface energy balance by approximately 40%. This summer increase in albedo, when viewed in absolute values, is as large as the difference between the forest and tundra transition. These results indicate that near future (<50 years) changes in growing-season albedo related to Arctic vegetation change are unlikely to be particularly large and might constitute a negative feedback to climate warming in certain circumstances. Future efforts to calculate energy budgets and a sensible heating feedback in the Arctic will require more detailed information about the relative abundance of different ground cover types, particularly shrub species and their respective growth forms and phenology.
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Affiliation(s)
- Scott N Williamson
- Department of Biological Sciences, University of Alberta, Edmonton, AB, T6G 2E9, Canada.
| | - Isabel C Barrio
- Department of Biological Sciences, University of Alberta, Edmonton, AB, T6G 2E9, Canada
| | - David S Hik
- Department of Biological Sciences, University of Alberta, Edmonton, AB, T6G 2E9, Canada
| | - John A Gamon
- Department of Biological Sciences, University of Alberta, Edmonton, AB, T6G 2E9, Canada
- Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, AB, T6G 2E3, Canada
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195
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Chen J, Luo Y, Xia J, Wilcox KR, Cao J, Zhou X, Jiang L, Niu S, Estera KY, Huang R, Wu F, Hu T, Liang J, Shi Z, Guo J, Wang RW. Warming Effects on Ecosystem Carbon Fluxes Are Modulated by Plant Functional Types. Ecosystems 2016. [DOI: 10.1007/s10021-016-0035-6] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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196
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Gruner DS, Bracken MES, Berger SA, Eriksson BK, Gamfeldt L, Matthiessen B, Moorthi S, Sommer U, Hillebrand H. Effects of experimental warming on biodiversity depend on ecosystem type and local species composition. OIKOS 2016. [DOI: 10.1111/oik.03688] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Daniel S. Gruner
- Dept of Entomology; Univ. of Maryland; College Park MD 20742-4454 USA
| | | | - Stella A. Berger
- Leibniz-Inst. of Freshwater Ecology and Inland Fisheries (IGB); Dept of Experimental Limnology; Stechlin Germany
| | - Britas Klemens Eriksson
- Marine Benthic Ecology and Evolution, Centre for Ecological and Evolutionary Studies; Univ. of Groningen; Groningen the Netherlands
| | - Lars Gamfeldt
- Dept of Marine Sciences; Univ. of Gothenburg; Gothenburg Sweden
| | | | - Stefanie Moorthi
- Inst. for Chemistry and Biology of the Marine Environment (ICBM); Carl-von-Ossietzky Univ. Oldenburg; Wilhelmshaven Germany
| | - Ulrich Sommer
- Helmoltz Centre for Ocean Research (GEOMAR); Kiel Germany
| | - Helmut Hillebrand
- Inst. for Chemistry and Biology of the Marine Environment (ICBM); Carl-von-Ossietzky Univ. Oldenburg; Wilhelmshaven Germany
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197
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Birkemoe T, Bergmann S, Hasle TE, Klanderud K. Experimental warming increases herbivory by leaf-chewing insects in an alpine plant community. Ecol Evol 2016; 6:6955-6962. [PMID: 28725372 PMCID: PMC5513215 DOI: 10.1002/ece3.2398] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Revised: 07/01/2016] [Accepted: 08/04/2016] [Indexed: 11/11/2022] Open
Abstract
Climate warming is predicted to affect species and trophic interactions worldwide, and alpine ecosystems are expected to be especially sensitive to changes. In this study, we used two ongoing climate warming (open-top chambers) experiments at Finse, southern Norway, to examine whether warming had an effect on herbivory by leaf-chewing insects in an alpine Dryas heath community. We recorded feeding marks on the most common vascular plant species in warmed and control plots at two experimental sites at different elevations and carried out a brief inventory of insect herbivores. Experimental warming increased herbivory on Dryas octopetala and Bistorta vivipara. Dryas octopetala also experienced increased herbivory at the lower and warmer site, indicating an overall positive effect of warming, whereas B. vivipara experienced an increased herbivory at the colder and higher site indicating a mixed effect of warming. The Lepidoptera Zygaena exulans and Sympistis nigrita were the two most common leaf-chewing insects in the Dryas heath. Based on the observed patterns of herbivory, the insects life cycles and feeding preferences, we argue that Z. exulans is the most important herbivore on B. vivipara, and S. nigrita the most important herbivore on D. octopetala. We conclude that if the degree of insect herbivory increases in a warmer world, as suggested by this study and others, complex interactions between plants, insects, and site-specific conditions make it hard to predict overall effects on plant communities.
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Affiliation(s)
- Tone Birkemoe
- Department of Ecology and Natural Resource Management Norwegian University of Life Sciences P.O. Box 5003 N-1432 Ås Norway
| | - Saskia Bergmann
- Department of Ecology and Natural Resource Management Norwegian University of Life Sciences P.O. Box 5003 N-1432 Ås Norway
| | - Toril E Hasle
- Department of Ecology and Natural Resource Management Norwegian University of Life Sciences P.O. Box 5003 N-1432 Ås Norway
| | - Kari Klanderud
- Department of Ecology and Natural Resource Management Norwegian University of Life Sciences P.O. Box 5003 N-1432 Ås Norway
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198
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Fisher JP, Estop‐Aragonés C, Thierry A, Charman DJ, Wolfe SA, Hartley IP, Murton JB, Williams M, Phoenix GK. The influence of vegetation and soil characteristics on active-layer thickness of permafrost soils in boreal forest. GLOBAL CHANGE BIOLOGY 2016; 22:3127-40. [PMID: 26855070 PMCID: PMC4999035 DOI: 10.1111/gcb.13248] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Accepted: 01/18/2016] [Indexed: 05/27/2023]
Abstract
Carbon release from thawing permafrost soils could significantly exacerbate global warming as the active-layer deepens, exposing more carbon to decay. Plant community and soil properties provide a major control on this by influencing the maximum depth of thaw each summer (active-layer thickness; ALT), but a quantitative understanding of the relative importance of plant and soil characteristics, and their interactions in determine ALTs, is currently lacking. To address this, we undertook an extensive survey of multiple vegetation and edaphic characteristics and ALTs across multiple plots in four field sites within boreal forest in the discontinuous permafrost zone (NWT, Canada). Our sites included mature black spruce, burned black spruce and paper birch, allowing us to determine vegetation and edaphic drivers that emerge as the most important and broadly applicable across these key vegetation and disturbance gradients, as well as providing insight into site-specific differences. Across sites, the most important vegetation characteristics limiting thaw (shallower ALTs) were tree leaf area index (LAI), moss layer thickness and understory LAI in that order. Thicker soil organic layers also reduced ALTs, though were less influential than moss thickness. Surface moisture (0-6 cm) promoted increased ALTs, whereas deeper soil moisture (11-16 cm) acted to modify the impact of the vegetation, in particular increasing the importance of understory or tree canopy shading in reducing thaw. These direct and indirect effects of moisture indicate that future changes in precipitation and evapotranspiration may have large influences on ALTs. Our work also suggests that forest fires cause greater ALTs by simultaneously decreasing multiple ecosystem characteristics which otherwise protect permafrost. Given that vegetation and edaphic characteristics have such clear and large influences on ALTs, our data provide a key benchmark against which to evaluate process models used to predict future impacts of climate warming on permafrost degradation and subsequent feedback to climate.
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Affiliation(s)
- James P. Fisher
- Department of Animal and Plant SciencesUniversity of SheffieldWestern BankSheffieldS10 2TNUK
| | | | - Aaron Thierry
- School of GeoSciencesUniversity of EdinburghKings BuildingsEdinburghEH9 3JNUK
| | - Dan J. Charman
- GeographyCollege of Life and Environmental ScienceUniversity of ExeterExeterEX4 4RJUK
| | - Stephen A. Wolfe
- Geological Survey of CanadaNatural Resources CanadaOttawaONK1A 0E8Canada
| | - Iain P. Hartley
- GeographyCollege of Life and Environmental ScienceUniversity of ExeterExeterEX4 4RJUK
| | | | - Mathew Williams
- School of GeoSciencesUniversity of EdinburghKings BuildingsEdinburghEH9 3JNUK
| | - Gareth K. Phoenix
- Department of Animal and Plant SciencesUniversity of SheffieldWestern BankSheffieldS10 2TNUK
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199
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O'Gorman EJ, Ólafsson ÓP, Demars BOL, Friberg N, Guðbergsson G, Hannesdóttir ER, Jackson MC, Johansson LS, McLaughlin ÓB, Ólafsson JS, Woodward G, Gíslason GM. Temperature effects on fish production across a natural thermal gradient. GLOBAL CHANGE BIOLOGY 2016; 22:3206-20. [PMID: 26936833 PMCID: PMC4991275 DOI: 10.1111/gcb.13233] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Accepted: 01/10/2016] [Indexed: 05/14/2023]
Abstract
Global warming is widely predicted to reduce the biomass production of top predators, or even result in species loss. Several exceptions to this expectation have been identified, however, and it is vital that we understand the underlying mechanisms if we are to improve our ability to predict future trends. Here, we used a natural warming experiment in Iceland and quantitative theoretical predictions to investigate the success of brown trout as top predators across a stream temperature gradient (4-25 °C). Brown trout are at the northern limit of their geographic distribution in this system, with ambient stream temperatures below their optimum for maximal growth, and above it in the warmest streams. A five-month mark-recapture study revealed that population abundance, biomass, growth rate, and production of trout all increased with stream temperature. We identified two mechanisms that contributed to these responses: (1) trout became more selective in their diet as stream temperature increased, feeding higher in the food web and increasing in trophic position; and (2) trophic transfer through the food web was more efficient in the warmer streams. We found little evidence to support a third potential mechanism: that external subsidies would play a more important role in the diet of trout with increasing stream temperature. Resource availability was also amplified through the trophic levels with warming, as predicted by metabolic theory in nutrient-replete systems. These results highlight circumstances in which top predators can thrive in warmer environments and contribute to our knowledge of warming impacts on natural communities and ecosystem functioning.
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Affiliation(s)
- Eoin J. O'Gorman
- Department of Life SciencesImperial College LondonSilwood Park Campus, Buckhurst Road, AscotBerkshireSL5 7PYUK
| | - Ólafur P. Ólafsson
- Institute of Life and Environmental SciencesUniversity of IcelandAskja, Sturlugata 7Reykjavík101Iceland
| | | | - Nikolai Friberg
- Norwegian Institute for Water Research (NIVA)Gaustadalléen 21OsloN‐0349Norway
| | | | - Elísabet R. Hannesdóttir
- Institute of Life and Environmental SciencesUniversity of IcelandAskja, Sturlugata 7Reykjavík101Iceland
- Institute of Freshwater FisheriesKeldnaholtReykjavík112Iceland
| | - Michelle C. Jackson
- Centre for Invasion BiologyDepartment of Zoology and EntomologyUniversity of PretoriaHatfield 0026GautengSouth Africa
| | | | - Órla B. McLaughlin
- Department of Life SciencesImperial College LondonSilwood Park Campus, Buckhurst Road, AscotBerkshireSL5 7PYUK
- Institut National de la Recherche Agronomique (INRA)UMR 1347 Agroécologie17 rue Sully ‐ BP 86510Dijon21065France
| | - Jón S. Ólafsson
- Institute of Freshwater FisheriesKeldnaholtReykjavík112Iceland
| | - Guy Woodward
- Department of Life SciencesImperial College LondonSilwood Park Campus, Buckhurst Road, AscotBerkshireSL5 7PYUK
| | - Gísli M. Gíslason
- Institute of Life and Environmental SciencesUniversity of IcelandAskja, Sturlugata 7Reykjavík101Iceland
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200
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Hedenås H, Christensen P, Svensson J. Changes in vegetation cover and composition in the Swedish mountain region. ENVIRONMENTAL MONITORING AND ASSESSMENT 2016; 188:452. [PMID: 27387190 DOI: 10.1007/s10661-016-5457-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Accepted: 06/27/2016] [Indexed: 06/06/2023]
Abstract
Climate change, higher levels of natural resource demands, and changing land use will likely lead to changes in vegetation configuration in the mountain regions. The aim of this study was to determine if the vegetation cover and composition have changed in the Swedish region of the Scandinavian Mountain Range, based on data from the long-term landscape biodiversity monitoring program NILS (National Inventory of Landscapes in Sweden). Habitat type and vegetation cover were assessed in 1740 systematically distributed permanent field plots grouped into 145 sample units across the mountain range. Horvitz-Thompson estimations were used to estimate the present areal extension of the alpine and the mountain birch forest areas of the mountain range, the cover of trees, shrubs, and plants, and the composition of the bottom layer vegetation. We employed the data from two subsequent 5-year monitoring periods, 2003-2007 and 2008-2012, to determine if there have been any changes in these characteristics. We found that the extension of the alpine and the mountain birch forest areas has not changed between the inventory phases. However, the total tree canopy cover increased in the alpine area, the cover of graminoids and dwarf shrubs and the total cover of field vegetation increased in both the alpine area and the mountain birch forest, the bryophytes decreased in the alpine area, and the foliose lichens decreased in the mountain birch forest. The observed changes in vegetation cover and composition, as assessed by systematic data in a national and regional monitoring scheme, can validate the results of local studies, experimental studies, and models. Through benchmark assessments, monitoring data also contributes to governmental policies and land-management strategies as well as to directed cause and effect analyses.
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Affiliation(s)
- Henrik Hedenås
- Department of Forest Resource Management, Swedish University of Agricultural Sciences, Skogsmarksgränd, 901 83, Umeå, Sweden.
| | - Pernilla Christensen
- Department of Forest Resource Management, Swedish University of Agricultural Sciences, Skogsmarksgränd, 901 83, Umeå, Sweden
| | - Johan Svensson
- Department of Wildlife, Fish, and Environmental Studies, Swedish University of Agricultural Sciences, 901 83, Umeå, Sweden
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