![]() This does mean though that they need quite a bit of moisture, so when it is dry they will go temporarily dormant, and revive when there is more moisture again. Lichens and mosses for example are able to grow on rock and absorb water out of the air. This creates small communities of distinct plants dotted throughout the landscape. As well, the patchy water logged versus rocky-dry areas make it so plants either need to be able to survive in lots of water, or with little water. They must also be able to withstand the freeze-thaw dynamics and survive with little soil nutrients. In saying this, plants in the tundra must have shallow roots that stretch outwards instead of down into the soil. The absence of trees in the arctic tundra is partially due to the growing season, where trees need at least 1 month of steady temperatures above 10☌ (50 ☏), but is mainly due to the permafrost limiting root growth. In the windiest areas you can find matted cushion plants and some grasses, on rocky areas mainly lichens, mosses and fungi, and the vascular plants, dwarf-shrubs, and peat mosses dominate the “less harsh” areas, where the snow melts sooner, the wind is not so persistent, and there is lots of groundwater. Microclimates of varying degrees of air moisture, wind, soil moisture, soil quality/soil type and available nutrients control the plant communities and make for the interesting patterns seen in the tundra. Plants include things like: low-lying grasess, like tundra grass ( Dupontia fischeri ), mosses, such as Sphagnum mosses, lichen, largely reindeer lichen ( Cladonia rangiferina ), low-lying shrubs, mountain cranberry ( Vaccinium vitis-idaea ) for example, cushion plants like the three toothed saxifrage ( Saxifraga tricuspidata ), some 400 flowering vascular plants, like the Dwarf Fireweed ( Chamerion latifolium ), and even bush-like willows (Family Salicaceae) that only grow around 8cm (3 inches) off the ground. Plant adaptations to the The Arctic Tundraīetween the harsh climate, short growing seasons (50-60 days), and poor soil conditions, the arctic tundra is a difficult biome for plants to grow. This permafrost does a few key things: (1) it prevents the growth of large trees, because they can not put their roots deep into the ground (2) The melting of its top layer provides much of the water in the ecosystem and creates the ponds and wetlands throughout the landscape (3) it prevents the draining of water, which causes the water-logged soils mentioned above (4) it stores large amounts of carbon, methane and other gases. The permafrost starts anywhere from 25-100 cm down (remember where the active layer ends?) and can go all the way down to 450 meters (~1475 ft) below the surface. Permafrost refers to the soil that is frozen solid all year round, and does not even melt in the summer. The most distinct part of the arctic tundra soil, and perhaps the whole biome, is that of permafrost. These factors further increase difficulty for life in the soil, including plants and different organisms like worms or microorganisms. The cold weather and high water content creates poor conditions for decomposition, and most of the available nutrients come from animal waste. This small active layer is also relatively low in nutrients and is usually water-logged, meaning that the water does not drain and there is very little dry space in the soil. Similar to the other trends we have seen, the further north you go, the smaller active layer you have and the more limited growth is. Life here is very interesting because it continually experiences freezing and thawing between the seasons. The active layer of the soil is the part that melts in the summer and allows life, and can be from 25-100cm (10-40 inches) deep. ![]() The arctic tundra does not have proper soil layers, like those that can be found in a temperate grassland for example, but instead has a very small active layer, which is the part of the soil that contains life and allows plant growth, and permafrost.This soil experiences a lot of freezing and thawing and is classed as a Gelisol Soil. ![]()
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