Concept information
Preferred term
ARCTIC WOLVES
Definition
- Arctic ecosystems are being strongly affected by global change and there is strong interest in being able to predict ecosystem responses to disturbance and for developing viable strategies for conserving biodiversity and managing the consequences of climate changes. Several international initiatives have been implemented to monitor and study the response to global warming of some tundra ecosystem components such as plants or permafrost. However, similar internationally-coordinated efforts for research on arctic food webs focusing on wildlife species (i.e. birds and mammals) are lacking. Yet, arctic food webs throughout the circumpolar world generally contain few species and are often dominated by the same groups of species, and so lend themselves well as systems suitable for comparative research. Our project will focus on key species of herbivores (e.g. geese, lemmings, and muskox), insectivores (e.g. shorebirds), and predators (e.g. foxes, snowy owls, falcons, gulls, and jaegers), and their interactions at a large number of arctic sites across North America and Eurasia. There will be a special effort in providing data from the winter period, which is poorly described in the Arctic. A primary objective is to document patterns of abundance, distribution, and phenology of reproduction of these species over large spatial and temporal scales using standardized protocols. These patterns will be related to local and regional climatic conditions. A secondary objective is to determine the relative importance of bottom-up (resources) and top-down (predators) forces in structuring these arctic food webs, and how climate affects these trophic linkages. Lemmings, which form the backbone of the terrestrial food web of the arctic, fluctuate cyclically in many locations, reaching peaks every 3-4 years. These cycles are reflected in cyclic abundance of specialist predators such as arctic foxes, snowy owls, jaegers, and weasels, which in turn may affect production of alternative prey like geese and shorebirds. Some of these complex interactions have been studied locally (Gauthier et al. 2004), but there have been few quantitative regional surveys to investigate synchrony among independent populations. In particular, we do not know how much synchrony occurs between or within continents, and this will affect how predators can operate within these polar ecosystems (Krebs et al. 2002). Geese and shorebirds are migratory birds using the Arctic only for summer breeding and offer an interesting contrast. Many goose populations have increased worldwide in recent decades, and goose grazing now has a large impact on several arctic wetlands. Although their population increase is largely fuelled by events occurring on their wintering grounds, they impose a large allochthonous influence on the tundra that seriously impacts ecosystem functioning (Abrahams et al. 2005, Gauthier et al. 2005). In contrast, many shorebird species appear to be declining worldwide, largely for unknown reasons (International Wader Study Group 2003). Shorebirds are a vital component of Arctic biodiversity with 37 species present in various parts of the circumpolar Arctic, but their globe-spanning migrations put their populations more at risk than most other species. Indeed, as global change will occur at varying speed and intensity at different latitudes, they will face multiple threats throughout their annual range, posing unique challenges for conservation. Arctic foxes are key predators of the arctic tundra that feed mostly on lemmings and birds. Their habitats have been recently invaded by red foxes in many parts of Eurasia and North America. Global warming should exacerbate this pattern but consequences on the arctic food chain are currently unknown. Foxes constitute a prime example of the changes in community structure that probably awaits the arctic tundra. Our project will build on arctic sites that already have a history of monitoring the wildlife species described in this proposal (core sites). Other sites will be added for the duration of IPY to expand the spatial coverage to poorly-known areas of the tundra (secondary sites). Inclusion of sites that lack some significant components of the arctic biota (e.g. islands without lemmings, geese or weasels) should allow fruitful comparisons to understand the role of these species in the arctic ecosystem. The abundance and distribution of all relevant species will be determined annually using the same technique at all sites. For birds, this will be largely determined by finding the nests of breeding individuals, which will also provide information on phenology. Similarly, for foxes this will be based on finding and monitoring active dens. For lemmings, various trapping techniques (snap and live-trapping) will be used. We will take blood, hair or feather samples from vertebrates (especially nomadic predators) for genetic and isotopic analysis to better understand population differentiation and trophic linkages. Exclosures will be built to monitor resource availability for herbivores, and their grazing impact. Insects will also be sampled to determine their seasonal abundance for insectivorous birds. Radio-tracking of some species will be used to monitor patterns of habitat use and activity. Winter work of resident arctic species will rely on direct observations or remote techniques (e.g. satellite or GPS radio-tracking). Climatic data will also be recorded at most sites year-round using automated stations. Our leading principle will be to collect data and to conduct experiments using a set of standard protocols that will allow comparison across all sites, and eventually meta-analyses of data from several sites.Abrahams, KF et al. 2005. Glob. Change Biol.11:841-855. Gauthier G et al. 2004. Integr. Comp. Biol. 44:119-129 Gauthier, G et al. Glob. Change Biol. 11:856-868. Krebs CJ et al. 2002. Can. J. Zool. 80:1323-1333. Summary provided by http://classic.ipy.org/development/eoi/proposal-details.php?id=11 (en)
Broader concept
- A - C (en)
URI
https://gcmd.earthdata.nasa.gov/kms/concept/4ba24787-27f8-4d22-819a-b32efe17733c
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