What is the Artic Shrub Expansion? In this article, we will tackle the question and predict what research might be done in the future with this.
Figure 1: Shrub
Introduction
Vegetation in the Arctic consists of various shrub types that grow well in the extreme conditions of the tundra. Shrubs are woody plants expanding across the Arctic in biomass and abundance primarily due to a warming climate.
Figure 2: The three categories of shrub expansion- 1) infilling/filling of existing shrub areas, 2) growth increase and 3) range increase.
Shrub increase is categorized into three areas:
1) infilling/filling of existing shrub areas,
2) growth increase
3) range increase
These shrubs are increasing due to the warmer temperature of the Arctic as well as added tundra disturbances. Satellites and aerial photographs have shown evidence of this expansion of shrubs.
Increases in spatial temperatures are linked to shrub expansion and warming temperatures are connected to growth in shrub height. In the summer, temperature increases have promoted plant and ring-width development.
Shrub growth has also been linked to tundra disturbances. Tundra disturbances include fire and permafrost degradation and create sites for tall shrubs to grow well. A recent decrease in permafrost, which is ground that has been frozen for at least 2 years, due to warmer temperatures is linked to an increase in shrubs. Wildfires have also been connected to shrub expansion over the long term.
Figure 2: A diagram depicting the connection of a warming climate to shrub expansion.
The expansion of shrubs in the Arctic will increase the carbon uptake of the plants, which can decrease the total amount of carbon in the ecosystem. More shrubs will also reduce the amount of radiation reflected from the surface of the snow because taller shrubs will cover more of the snow. This consequently alters the energy balance and timing of the melt of snow.
Shrub expansion can also decrease species diversity. Increasing shrub height and cover can cause shade-intolerant species to die off. Lichens and moss are among the species that have decreased when shrubs have increased, which could impact reindeer and caribou populations and soil temperature and depth, respectively.
In the future, research will be conducted to determine the connection between temperature and soil moisture and depth, nutrient availability, and other dynamics and their effect on shrub expansion. Researchers will focus on the different kinds of shrubs and their impacts on different regions of the Arctic because the location of the shrubs can cause different effects on their growth and impact.
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