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Aphid-willow interactions in a high Arctic ecosystem: responses to raised temperature and goose disturbance.

https://arctichealth.org/en/permalink/ahliterature258051
Source
Glob Chang Biol. 2013 Dec;19(12):3698-708
Publication Type
Article
Date
Dec-2013
Author
Mark A K Gillespie
Ingibjörg S Jónsdóttir
Ian D Hodkinson
Elisabeth J Cooper
Author Affiliation
Institute of Integrative and Comparative Biology, University of Leeds, Woodhouse Lane, Leeds, LS2 9JT, UK.
Source
Glob Chang Biol. 2013 Dec;19(12):3698-708
Date
Dec-2013
Language
English
Publication Type
Article
Keywords
Animals
Aphids - growth & development - physiology
Arctic Regions
Climate change
Geese - physiology
Herbivory
Population Dynamics
Reproduction
Salix - growth & development - physiology
Seasons
Svalbard
Temperature
Abstract
Recently, there have been several studies using open top chambers (OTCs) or cloches to examine the response of Arctic plant communities to artificially elevated temperatures. Few, however, have investigated multitrophic systems, or the effects of both temperature and vertebrate grazing treatments on invertebrates. This study investigated trophic interactions between an herbivorous insect (Sitobion calvulum, Aphididae), a woody perennial host plant (Salix polaris) and a selective vertebrate grazer (barnacle geese, Branta leucopsis). In a factorial experiment, the responses of the insect and its host to elevated temperatures using open top chambers (OTCs) and to three levels of goose grazing pressure were assessed over two summer growing seasons (2004 and 2005). OTCs significantly enhanced the leaf phenology of Salix in both years and there was a significant OTC by goose presence interaction in 2004. Salix leaf number was unaffected by treatments in both years, but OTCs increased leaf size and mass in 2005. Salix reproduction and the phenology of flowers were unaffected by both treatments. Aphid densities were increased by OTCs but unaffected by goose presence in both years. While goose presence had little effect on aphid density or host plant phenology in this system, the OTC effects provide interesting insights into the possibility of phenological synchrony disruption. The advanced phenology of Salix effectively lengthens the growing season for the plant, but despite a close association with leaf maturity, the population dynamics of the aphid appeared to lack a similar phenological response, except for the increased population observed.
PubMed ID
23749580 View in PubMed
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Are heat and cold resistance of Arctic species affected by successive extreme temperature events?

https://arctichealth.org/en/permalink/ahliterature95738
Source
New Phytologist. 2006;170(2):291-300
Publication Type
Article
Date
2006
Author
Marchand, FL
Kockelbergh, F
van de Vijver, B
Beyens, L
Nijs, I
Author Affiliation
Research Group Plant and Vegetation Ecology, Department of Biology, University of Antwerp, Campus Drie Eiken, Universiteitsplein 1, B-2610 Wilrijk, Belgium.
Source
New Phytologist. 2006;170(2):291-300
Date
2006
Language
English
Publication Type
Article
Keywords
Arctic Regions
Carex Plant - growth & development - physiology
Chlorophyll - metabolism
Cold Climate
Ericaceae - growth & development - physiology
Fluorescence
Greenhouse Effect
Hot Temperature
Photosynthesis - physiology
Photosystem II Protein Complex - physiology
Plant Leaves - growth & development - physiology
Polygonum - growth & development - physiology
Salix - growth & development - physiology
Species Specificity
Abstract
Extreme temperature events are projected to increase in frequency in a future climate. As successive extremes could occur more frequently, patches of vulnerable tundra vegetation were exposed to two consecutive heat waves (HWs) of 10 d each, with a 5-d recovery period in between. Surface temperatures during the HWs were increased approximately 6 degrees C using infrared irradiation sources. In three of the four target species (Pyrola grandiflora, Polygonum viviparum and Carex bigelowii), plant conditions improved upon the first exposure. Depending on species, leaf relative growth, leaf chlorophyll content or maximal photochemical efficiency was increased. In P. grandiflora the positive effects of the heat on the photosynthetic apparatus led to augmented net photosynthesis. By contrast, Salix arctica responded mainly negatively, indicating species-specific responses. During the second HW, leaf mortality suddenly increased, indicating that the heat stress induced by the extreme events lasted too long and negatively influenced the species resistance to high temperature. After the HWs, when plants were exposed to (low) ambient temperatures again, plant performance deteriorated further, indicating possible loss of cold resistance.
PubMed ID
16608454 View in PubMed
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Phenological sequences reveal aggregate life history response to climatic warming.

https://arctichealth.org/en/permalink/ahliterature95551
Source
Ecology. 2008 Feb;89(2):363-70
Publication Type
Article
Date
Feb-2008
Author
Post Eric S
Pedersen Christian
Wilmers Christopher C
Forchhammer Mads C
Author Affiliation
Department of Biology, Penn State University, 208 Mueller Lab, University Park, Pennsylvania 16802, USA. Esp10@psu.edu
Source
Ecology. 2008 Feb;89(2):363-70
Date
Feb-2008
Language
English
Publication Type
Article
Keywords
Adaptation, Physiological
Betula - growth & development - physiology
Caryophyllaceae - growth & development - physiology
Ecosystem
Greenhouse Effect
Population Dynamics
Population Growth
Salix - growth & development - physiology
Species Specificity
Temperature
Time Factors
Abstract
Climatic warming is associated with organisms breeding earlier in the season than is typical for their species. In some species, however, response to warming is more complex than a simple advance in the timing of all life history events preceding reproduction. Disparities in the extent to which different components of the reproductive phenology of organisms vary with climatic warming indicate that not all life history events are equally responsive to environmental variation. Here, we propose that our understanding of phenological response to climate change can be improved by considering entire sequences of events comprising the aggregate life histories of organisms preceding reproduction. We present results of a two-year warming experiment conducted on 33 individuals of three plant species inhabiting a low-arctic site. Analysis of phenological sequences of three key events for each species revealed how the aggregate life histories preceding reproduction responded to warming, and which individual events exerted the greatest influence on aggregate life history variation. For alpine chickweed (Cerastium alpinum), warming elicited a shortening of the duration of the emergence stage by 2.5 days on average, but the aggregate life history did not differ between warmed and ambient plots. For gray willow (Salix glauca), however, all phenological events monitored occurred earlier on warmed than on ambient plots, and warming reduced the aggregate life history of this species by 22 days on average. Similarly, in dwarf birch (Betula nana), warming advanced flower bud set, blooming, and fruit set and reduced the aggregate life history by 27 days on average. Our approach provides important insight into life history responses of many organisms to climate change and other forms of environmental variation. Such insight may be compromised by considering changes in individual phenological events in isolation.
PubMed ID
18409426 View in PubMed
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