High-Arctic Plant—Herbivore Interactions under Climate Influence

Berg, Thomas B.; Schmidt, Niels Martin; Høye, Toke T.; Aastrup, Peter; Hendrichsen, Ditte Katrine; Forchhammer, Mads C.; Klein, David R.

doi:10.1016/s0065-2504(07)00012-8

Cited by 31 publications

(31 citation statements)

References 47 publications

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“…During summer, muskoxen predominantly feed in the grasslands and mires mainly eating graminoids (Kristensen et al 2011), in winter they prefer areas with thin snowcover, where it is easier for them to access the vegetation (Berg et al 2008). When muskoxen feed on graminoids, they press the incisors against the pad and pull, leaving the vegetation cut just a couple of centimeters above the surface (Kristensen et al 2011).…”

Section: Site Descriptionmentioning

confidence: 99%

Effects of simulated increased grazing on carbon allocation patterns in a high arctic mire

2014

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Herbivory is an important part of most ecosystems, and grazing alone can have a considerable impact on the ecosystems carbon balance with both direct and indirect effects. Removal of above-ground biomass by consumption of herbivores will change the below-ground carbon stock; the reduction of litter that goes into the ground will influence the total ecosystem carbon content. Little is however known about how plant-herbivory interactions effect the carbon balance, in particular methane emissions, of high arctic mires. We hypothesized that increased grazing pressure will change carbon allocation patterns resulting in decreased net ecosystem uptake of carbon and subsequently in lower methane emissions. An in-situ field experiment was conducted over 3 years in a high arctic mire at Zackenberg in NE Greenland. The experiment consisted of three treatments, with five replicates of each (1) control, (2) vascular plants were removed (NV), (3) clipped twice each growing season in order to simulate increased muskox grazing. Immediately after the initiation of the experiment net ecosystem uptake of CO 2 decreased in clipped plots (mean total decrease for the three following years was 35 %). One year into the experiment a significantly lower CH 4 emission was observed in these plots, the total mean reduction for the following 2 years was 26 %. Three years into the experiment significantly lower substrate (acetic acid) availability for CH 4 production was observed (27 % reduction). NV plots had a mean decrease in CO 2 uptake of 113 %, a 62 % decrease in ecosystem respiration and an 84 % decrease in CH 4 emission (mean of all 3 years). Our study shows that increased grazing pressure in a high arctic mire can lead to significant changes in the carbon balance, with lower CO 2 uptake leading to lower production of substrate for CH 4 formation and in lower CH 4 emission.

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Section: Site Descriptionmentioning

confidence: 99%

Effects of simulated increased grazing on carbon allocation patterns in a high arctic mire

2014

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“…These vegetation types are in this study lumped together as "Other vegetation types" (43% of the study area). These three vegetation types are all visited by muskoxen in summer (Berg et al, 2008), but foraging takes place in the graminoid-dominated areas and Salix snowbeds (Kristensen et al, 2011) (see below).…”

Section: Study Areamentioning

confidence: 99%

Effects of Simulated Grazing in Ungrazed Wet Sedge Tundra in the High Arctic

Elliott

Henry

2011

Arctic, Antarctic, and Alpine Research

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“…Singing voles (Microtus miurus) and collared lemmings (Dicronstonyx rubricatus) have been recorded in rocky areas very near DH (Batzli and Henttonen 1990;Johnson 2008). Batzli and Henttonen (1990) suggested that rodent densities near the LTER are generally limited by food availability, particularly during outbreak years; however, they may also be limited top-down by predators similar to lemmings in coastal tundra (e.g., Batzli et al 1980;Berg et al 2008).…”

Section: Mammalian Herbivoresmentioning

confidence: 99%

Mammalian herbivory exacerbates plant community responses to long-term increased soil nutrients in two Alaskan tundra plant communities

LauraGough

Johnson

2018

Arctic Science

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Abstract:The interaction between bottom-up and top-down forces in regulating plant communities is a long-standing topic of interest in ecology. Factorial field experiments examining these factors have been relatively few, but recent meta-analyses provide predictions that can be tested in a range of ecosystems. We tested the prediction that added nutrients would reduce species richness and evenness, while herbivore activity would offset those changes in two tundra plant communities after 11 years. In moist acidic tundra (MAT), herbivores reduced richness more in fertilized plots when mammals were present compared with fertilized plots without herbivores. In dry heath (DH), evenness was significantly reduced in fertilized plots only when herbivores were present, also providing evidence that herbivores enhanced community changes caused by greater nutrient availability. The difference in response between MAT and the meta-analysis predictions appears to be driven by Betula nana, the species that dramatically increased with added nutrients in MAT. Unlike in similar studies and in DH, B. nana is not as palatable as most of the species in the community and is generally avoided by herbivores. These results highlight how the effects of herbivory and nutrients differ across communities and can be affected by the traits of the species present.Key words: herbivory, nutrients, tundra, species richness, species evenness.Résumé : L'interaction entre les forces ascendantes (ressources) et descendantes (prédateurs) dans la régulation de communautés végétales est depuis longtemps un sujet d'intérêt en écologie. Les expériences factorielles sur le terrain examinant ces facteurs ont été relativement peu nombreuses, mais les méta-analyses récentes fournissent des prédictions qui peuvent être vérifiées au niveau de divers écosystèmes. Nous avons vérifié la prédiction selon laquelle des substances nutritives ajoutées réduiraient la richesse et la régularité des espèces tandis que les activités des herbivores pallieraient ces changements chez deux communautés végétales de toundra après onze ans. Dans la toundra acide humide (TAH), les herbivores ont davantage réduit la richesse dans les parcelles fertilisées lorsque les mammifères étaient présents en comparaison des parcelles fertilisées sans herbivores. Dans les landes sèches (LS), la régularité a été significativement réduite au niveau des parcelles fertilisées seulement lorsque les herbivores étaient présents, fournissant aussi la preuve que les herbivores ont amélioré les changements des communautés végétales en raison de plus grande disponibilité nutritive. La différence de la réponse entre la TAH et les prédictions des méta-analyses semble être déterminée par Betula nana, l'espèce qui a dramatiquement augmenté avec l'ajout de substances nutritives dans la TAH.

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High-Arctic Plant—Herbivore Interactions under Climate Influence

Cited by 31 publications

References 47 publications

Effects of simulated increased grazing on carbon allocation patterns in a high arctic mire

Effects of simulated increased grazing on carbon allocation patterns in a high arctic mire

Effects of Simulated Grazing in Ungrazed Wet Sedge Tundra in the High Arctic

Mammalian herbivory exacerbates plant community responses to long-term increased soil nutrients in two Alaskan tundra plant communities

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