High-Arctic Plant-Herbivore Interactions under Climate Influence
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Data from Zackenberg show that timing of snowmelt, the length of the growing season and summer temperature are the basic variables that determine the phenology of flowering and primary production upon which the herbivores depend, and snow may be the most important climatic factor affecting the different trophic levels and the interactions between them. Hence, the spatio-temporal distribution of snow, as well as thawing events during winter, may have considerable effects on the herbivores by influencing their access to forage in winter. During winter, musk oxen prefer areas with a thin snow-cover, where food is most easily accessible. In contrast, lemmings seek areas with thick snow-cover, which provide protection from the cold and some predators. Therefore, lemmings may be affected directly by both the timing of onset and the duration of winter snow-cover.
Musk oxen significantly reduced the productivity of arctic willow, while high densities of collared lemmings during winter reduced the production of mountain averts flowers in the following summer. Under a deep snow-layer scenario, climate and the previous year's density of musk oxen had a negative effect on the present year's production of arctic willow. Previous year's primary production of arctic willow, in turn, significantly affected the present year's density of musk oxen positively. Climatic factors that affect primary production of plants indirectly, influenced the spatial distribution of herbivores. Additionally, snow distribution directly affected the distribution of herbivores, and hence, in turn, affected the plant community by selective feeding and locally reducing the standing biomass of forage plants.
Although only few moth larvae were observed at Zackenberg, these had in some cases important local effects owing to their foraging on up to 60% of the flower stands on individual mountain avens.
UV-B radiation induces plants to produce secondary plant metabolites, which protects tissues against UV-B damage. This results in lower production of anti-herbivore defenses and improves the nutritional quality of the food plants. Zackenberg data on the relationship between variation in density of collared lemmings in winter and UV-B radiation indirectly supports this mechanism, which was originally proposed on the basis of a positive relationship between UV-B radiation and reproduction in two sub-arctic species of hares (Lepus timidus and Lepus americanus).
Original language | English |
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Publisher | Elsevier |
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Volume | 40 |
Number of pages | 275 |
DOIs | |
Publication status | Published - 2008 |
Series | Advances in Ecological Research |
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Volume | 40 |
Bibliographical note
KeyWords Plus: SEX-BIASED HERBIVORY; VERTEBRATE HERBIVORES; MAMMALIAN HERBIVORES; NORTHEAST GREENLAND; POPULATION-CYCLES; OVIBOS-MOSCHATUS; DYNAMICS; MUSKOXEN; SALIX; AVAILABILITY
ID: 10590574