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| Effects of Climate Change on Arctic vegetation | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Climate is predicted to warm most dramatically at high latitudes in response to global atmospheric change (Beringeret al. 2001). The effects of climate change may affect the various ecosystems around the globe. Climate change can influence the amount of nutrients in the soils, which would ultimately affect the vegetation in a biome, The one biome that has been intensely studied about the effects of global climate change is the arctic tundra (Hollister and Webber 2000). According to various climate models, the predicted increase for the arctic tundra is between 2 and 4o in the summer and 1-5o in the winter (Press et al. 1998). | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| The arctic plays a crucial role in the Earth system. The arctic tundra occurs between 30o and 0o N S (Antarctic in the south, Arctic in the north). The tundra covers a good portion of the earth's landmass, 22%. It also sensitive to climate changes (Chapin et al. 2000; Lesica and Steele 1996). | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Vegetation and various nutrients | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Vegetation response to climatic warming could affect the regional carbon storage (Rupp et al. 2000; White et al. 2000). The tundra contains an estimate of 35% of the world's soil carbon pool (McGuire et al. 1996; Chapin et al. 2000), which can hold a maximum of 95% of the nutrients for the plants (Robinson et al. 1997). The carbon storage can vary according the various arctic tundra regions across the globe (Chapin et al. 2000). Climate change in this biome has the potential of influencing the carbon storage (McGuire et al. 1996). If the temperature increases globally, the liter decomposition would increase the release of carbon and nutrients out of the Arctic soils (Robinson et al. 1997; Hobbie 1996; White et al 2000; Press et al. 1998). This would then affect the amount of carbon and nutrients that can be taken up by the plants within the arctic tundra. However, the effects vary across the arctic tundra because of the various regional climate responses (Walker 2000). These responses could cause more warming due to the elevated levels of carbon in the soil. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| If there is an increase of temperature due to climate change, there can be devastating effects on the vegetation in the arctic tundra. For instance, increased temperatures would cause a longer growing season in the arctic tundra, which has increased by 2.6 days per decade (Chapin et al. 2000). | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Also, there could also be a big increase in the soil moisture content (Chapin et al. 2000; Robinson et al. 1997), which cause changes in the arctic. This would ultimately affect the control the litter decomposition in the arctic tundra (Robinson et al. 1997). Also, higher soil temperatures would affect the permafrost by melting it by increasing the drainage in the arctic tundra. Also this would ultimately affect the biomass, annual growth and decomposition in the ecosystem (Camillet al. 2001). | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Climate change can affect the plant community composition the arctic tundra. This could alter the rates of carbon and other nutrients due to the tundra's high diversity. Warm temperatures could cause some of the arctic species to disappear because they are not well-adapted to warm temperatures (Hobbie 1996). | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Vegetation Response Models | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| There are several ways of determining the potential effects of climate change on arctic vegetation. The most popular way is by using models, such as the parameter-elevation regression on independent slopes model (PRISM). In this type of model, the most used variables are precipitation, temperature, elevation, and the vegetation in the arctic vegetation (Simpson et al. 2002). However, this type of model has several limitations such as sparse precipitation can cause errors in the data. Generally, precipitation increases with elevation in the PRISM model (Simpson et al. 2002). But this is not easy to determine in the model. This is not the case in Alaska because the mean annual precipitation is maximum in the coastal regions and the minimum was toward the central portion of the state (Simpson et al. 2002). According to PRISM, Alaskan climate patterns can be dictated by various physical aspects of geography along with global climate change (Simpson et al 2002). | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Another model that can be used to determine on how climate change could affect the arctic tundra is the terrestrial ecosystem model (TEM), which uses information about | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| the climate, elevation, soils and vegetation to make an accurate estimate (McGuire et al. 2000). From this model, one can get a good estimate based on one or several climatic variables on how climate change affects the vegetation in the arctic tundra. According to the TEM, the response of the carbon storage is quite sensitive to elevated levels of CO2 (McGuire et al. 2000), This is due to the fact that when the elevated levels of CO2 enter the carbon storage, this phenomenon would increase the amount of carbon that is in the storage Also responses of carbon storage tend to strongly correlated with temperature and soil moisture (McGuire et al. 2000). | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Both of the mentioned models did indicate how the various climatic factors can influence and affect the ecology of the vegetation in the Arctic. Every little factor has a critical role on how the plants react to climate change. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Effects on the Treeline | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Climate change can affect where the treeline is placed in the arctic tundra. Generally, during extremely warm years the treeline tends to be at higher elevations then during extremely cold years. According to Hobbie and Chapin, temperature tends to be the dominant factor in determining the position of the treeline in the arctic tundra (1998). Other mechanisms can have an effect on the position of the treeline, such as nutrients, water, and photosynthesis (Hobbie and Chapin 1998). Also, warmer temperatures have the tendency of enhancing the germination of various types of seeds. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| According to reverent evidence from the postglacial period, many species of trees have reached their maximum distribution limit. Also, there has been a change in the position of the treeline, however, they have been relatively small in North America (Lescop-Sinclair and Payette 1995). Also several studies have indicated that the treeline has been relatively stable in the past 3000 years (Lescop-Sinclair and Payette 1995; Szeicz and Macdonald 1995). | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Also according to recent studies, there has been evidence of increased population density in the treeline then before the recent postglacial period. This reverent evidence could indicate that the global temperature could be getting warmer (Lescop-Sinclair and Payette 1995; Szeicz and Macdonald 1995) because it could be that more seeds are being dispersed towards the treeline. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| The arctic tundra has definitely showed how a global biome can be very vulnerable to the potential effects of climate change/global warming. This would continue to show how the impacts can be very severe in this fragile ecosystem. This is truly the one biome that indicates about whether or not climate change is occurring globally. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Literature Cited | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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