but are not limited to, changes in temperature, rainfall, and growing season. Based on studies from the boreal ecosystems in the Yukon, a territory in northwestern Canada, climate change is having an impact on these abiotic factors. As a consequence, these effects drive changes in forest ecotone as well as marshlands or lakes in boreal ecosystems. This also concerns plant productivity and predator-prey interactions, which ultimately leads to habitat loss, fragmentation, and threatens biodiversity. In terms of boreal trees, the poleward limit for any given species is most likely defined by the temperature, whereas the equatorward limit is generally defined by competitive exclusion. As changes in climate occur, change in the corresponding weather variables follows, and ecosystem alterations involving timing for migration, mating, and plant blooming can occur. This can lead to the transition into a different type of ecosystem as the northward shift of plant and animal species has already been observed. Trees may expand towards the tundra; however, they may not survive due to various temperature or precipitation stressors. The rate depends on growth and reproductive rate, and adaptation ability of the vegetation. In addition, the migration of flora may lag behind warming for a few decades to a century, and in most cases warming happens faster than plants can keep up. Due to permafrost thaw and disturbance alterations such as fire and insect outbreaks, certain models have suggested that boreal forests have developed into a net carbon source instead of a net carbon sink. Although the trees in the boreal are aging, they continue to accumulate carbon into their biomass. However, if disturbed, higher than normal amounts of carbon will be lost to the atmosphere. In some areas, boreal ecosystems are located on a layer of permafrost, which is a layer of permanently frozen soil. The underground root systems of boreal trees are stabilized by permafrost, a process which permits the deeper trapping of carbon in the soil and aids in the regulation of hydrology. Permafrost is able to store double the amount of current atmospheric carbon that can be mobilized and released to the atmosphere as greenhouse gases when thawed under a warming climate feedback. Boreal ecosystems contain approximately 338 Pg (petagrams) of carbon in their soil, this is comparable to the amount which is stored in biomass in tropical ecosystems. Ecosystem services In boreal ecosystems, carbon cycling is a major producer of ecosystem services especially