Forest migration
Forest migration is the movement of large seed plant dominated communities in geographical space over time.
Suppression by the environment could include human land use, disturbance, unfulfilled species-specific resource needs, and/or climatic stress.
[3][4] These two major forces compete and change through time causing advances and retreats in the borders of plant populations' regions.
[1] Though dispersal and environmental suppressive forces continually act, a static range boundary may occur when there is no change in the rate of these two factors.
[citation needed] There has been debate over how plant populations move under rapid climate change situations.
[9] In this theory, populations moved directly from the area unaffected by glacial movement to their present boundaries by rare, long distance, successful dispersals.
[6] The Earth has entered another period of rapid climate change as a consequence of human's emissions of greenhouse gases.
[17][18] The ability of plant species to track climate change will be valuable information in predicting the future health, stability, and function of the Earth's forests in the coming decades.
The capacity for species to migrate in response to the ideal biogeographic range shifts has been questioned, especially in the context of extensive habitat fragmentation which occurs in modern-day landscapes.
[23] Simulation models are presented which incorporate two factors, land use pattern and means of dispersal, to assess potential responses of forest species to climatic warming.
[citation needed] As early as the late 1990s, foresters in the southern United States had realized that pines grew better in the seeding zones north of their historical ranges as a result of climate change.
[14] It is thought that if assisted migration is utilized in an organized manner, species could be saved by allowing for rapid movement across the landscape.
[18] The possible problems associated with this process include founder effects, and the introduction of unadapted genotypes which could harm the fitness of surrounding populations.
This is both beneficial for population stability as climates change, as well as increasing the likelihood of progeny success in new areas outside the current range.
To gain knowledge about the effects current climate change will have on the Earth's forests, many researchers have looked to past examples to draw information.
Many studies have investigated the movement of forest species across glacially disrupted areas in the early Holocene period.
The many unknowns about the limits of population migration, phenotypic plasticity, genetic capacity, species interaction, and current climate change cause have complicated the issue, and have made modeling, at this point, difficult.
[15][17][18][20] Studies should be directed to gaining knowledge about adaptation genetics, phenotypic limits of ecotypes, and create models incorporating more relevant factors.
The movement of Picea species in the past 1000 years has shown a strong connection to climate change through a model comparison.
[citation needed] In the more recent past, there has been documentation of elevation shifts in distribution of many core forest tree species of Catalonia.
[15] The populations of two tree species (European Beech, Fagus sylvatica; and Holm Oak, Quercus ilex) were evaluated in their dynamics over elevations through time.
The change in local microclimate of the region seemed to favor the success of the Holm Oak population, causing it to rise in elevation invading the natural range of European Beech.
The plants growing outside of the previous established range also have shown low injury rate, and signs of healthy growth.
