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Basic Chemical Hazards to Wildlife
Published in Jack Daugherty, Assessment of Chemical Exposures, 2020
Tundra, or arctic plain, covers most of the earth’s surface north of the coniferous forest belt. Tundra is dominated by sedge, heath, willow, moss, and lichen. Alpine tundra are high plains that occur above the timberline on mountains. Tundra have severe winters, low average temperatures, little snow or rainfall, and short summers. The arctic tundra is influenced by permafrost, a layer of permanently frozen subsoil in the ground. The surface soil of arctic tundra tends to be rocky, thawing in the Summer to varying depths. The combination of frozen ground and flat terrain impedes the drainage of water, which forms ponds and bogs that provide moisture for plants. Recurrent freezing and thawing of the soil, at drained locations, forms cracks in the ground in regularly patterned polygons. Poorly drained areas produce irregular land forms such as hummocks, knolls, frost boils, and earth stripes. Thawing slopes move soil down slope in warm months to produce solifluction, or flowing soil terraces. Alpine tundra commonly has bare rock-covered ground, called fell-fields, which support lichen growth.
Ecosystems and Energy Flow
Published in Gary S. Moore, Kathleen A. Bell, Living with the Earth, 2018
Gary S. Moore, Kathleen A. Bell
The tundra is limited to the upper latitudes of the northern hemisphere and forms a belt around the Arctic Ocean (Figure 1.6). The continents don’t extend southward sufficiently to create a similar biome in the southern latitudes. The tundra appears as a barren and treeless land consisting mostly of mosses, lichens, sedges, dwarf shrubs, and perennial forbs. The scattered shrubs and woody bushes lie close to the ground where they can preserve some warmth. The growing season is very short, lasting 6–10 weeks. The winters are long, dark, and cold with mean monthly temperatures below freezing (<0°C), and precipitation is less than 12 centimeters per year. Dryness is further encouraged by strong, drying winds. Beneath the thin layer of topsoil lies a permanent layer of ice or frozen soil known as permafrost. The permafrost, along with the cold weather, prevents the growth of larger plants and trees, prevents drainage, and leads to the formation of bogs and marshes.
Ecosystems: Diversity
Published in Yeqiao Wang, Terrestrial Ecosystems and Biodiversity, 2020
Polar ecosystems are characterized by extreme environments because of their high latitudes and low temperatures (below 5°C). Most are glaciated and permanently covered with a thick layer of ice—permafrost that reaches a thickness >600 m.[29] Geographically, the Arctic region in the Northern Hemisphere is primarily an ice-covered ocean surrounded by land, whereas the Antarctic in the Southern Hemisphere is a landmass surrounded by ocean. The Arctic and Antarctic regions differ in various ways regarding their geography, physical features, vegetation composition, and wildlife diversity. However, both regions have cold, dry, and windy climate, with short-growing seasons and prolonged darkness in the winter. They are sometimes referred to as polar deserts because of the lack of precipitation and low temperatures. Polar life survives through unique adaptations to withstand the cold. They contain 3–5% of global biodiversity and net primary productivity ranges from 1 to 1000 g/m2/yr.[30] Polar ecosystems are typically treeless, and in warmer and wetter places with organic soil, tundra vegetation is found and is dominated by simple plant communities of algae, lichens, mosses, and liverworts. They contain large mammals such as bears, caribou, wolves, foxes, walruses, and seals, and a variety of birds including penguins and migratory species. Most of them are homeotherms that have adaptations to allow them to thrive in cold environments. Polar ecosystems are vulnerable to human disturbances such as global climate change, pollution, and resource extraction. Global warming has facilitated the invasion of exotic species to polar regions, which used to be physiological filters.[31,32]
Research agenda for the Russian Far East and utilization of multi-platform comprehensive environmental observations
Published in International Journal of Digital Earth, 2021
Tuukka Petäjä, Kirill S. Ganzei, Hanna K. Lappalainen, Ksenia Tabakova, Risto Makkonen, Jouni Räisänen, Sergey Chalov, Markku Kulmala, Sergej Zilitinkevich, Petr Ya Baklanov, Renat B. Shakirov, Natalia V. Mishina, Evgeny G. Egidarev, Igor I. Kondrat’ev
Furthermore, a major part of the Northern Eurasian region is covered by continuous permafrost and changes in the turnover of the soil carbon stocks due to permafrost melting will likely switch the terrestrial ecosystems from being carbon sinks to being carbon sources (Koven et al. 2011; Schaefer et al. 2011). The permafrost soils and their greenhouse gas emissions in the tundra environment are important for the global climate. The current climate change scenarios underline the urgent need for a systematic permafrost monitoring, together with greenhouse gas measurements in various ecosystems. The processes of the Arctic Ocean, the interaction between the ocean and the other components of the Earth system including the air–sea exchange of momentum, heat, and matter, and the dynamics and thermodynamics of sea ice are major issues need to be better understood. For example, we need to quantify the effects on the ocean, surrounding continents, and aerosol budgets (Vihma et al. 2019) caused by sea ice decline.
Comparison of vegetation regeneration after wildfire between Mediterranean and tundra ecosystems by using Landsat images
Published in Annals of GIS, 2018
Cheuklap Au Yeung, Rongrong Li
The ARF perimeter is located within a permafrost zone. The growing season is usually less than 60 days annually, during which there are up to 24 h of sunlight. The landscape is plain and dotted with lakes, fens and low-gradient streams. The harsh tundra environment is dominated by dwarf shrubs, sedges, grasses and lichens, as tree growth is hindered by the short growing season. The area’s vegetation grows close to the ground and forms a dense mat. Woody species such as Salix arctica (Salicaceae) and Arctostaphylos spp. (Ericaceae) are widely distributed and form large communities. In addition, such lichens as Cladonia spp. (Cladoniaceae) are important components of the tussock tundra (Jandt et al. 2008). Unlike the Mediterranean ecosystem, the tundra biome is not adapted to wildfire. Hence, vegetation mortality during wildfires is usually greater.