Human migrationHuman migration is the movement of people from one place to another with intentions of settling, permanently or temporarily, at a new location (geographic region). The movement often occurs over long distances and from one country to another (external migration), but internal migration (within a single country) is also possible; indeed, this is the dominant form of human migration globally. Migration is often associated with better human capital at both individual and household level, and with better access to migration networks, facilitating a possible second move.
Bird migrationBird migration is the regular seasonal movement, often north and south, along a flyway, between breeding and wintering grounds. Many species of bird migrate. Migration carries high costs in predation and mortality, including from hunting by humans, and is driven primarily by the availability of food. It occurs mainly in the northern hemisphere, where birds are funnelled onto specific routes by natural barriers such as the Mediterranean Sea or the Caribbean Sea.
Post-glacial reboundPost-glacial rebound (also called isostatic rebound or crustal rebound) is the rise of land masses after the removal of the huge weight of ice sheets during the last glacial period, which had caused isostatic depression. Post-glacial rebound and isostatic depression are phases of glacial isostasy (glacial isostatic adjustment, glacioisostasy), the deformation of the Earth's crust in response to changes in ice mass distribution. The direct raising effects of post-glacial rebound are readily apparent in parts of Northern Eurasia, Northern America, Patagonia, and Antarctica.
Ice ageAn ice age is a long period of reduction in the temperature of Earth's surface and atmosphere, resulting in the presence or expansion of continental and polar ice sheets and alpine glaciers. Earth's climate alternates between ice ages and greenhouse periods, during which there are no glaciers on the planet. Earth is currently in the ice age called Quaternary glaciation. Individual pulses of cold climate within an ice age are termed glacial periods (or, alternatively, glacials, glaciations, glacial stages, stadials, stades, or colloquially, ice ages), and intermittent warm periods within an ice age are called interglacials or interstadials.
Ecological successionEcological succession is the process of change in the species that make up an ecological community over time. The process of succession occurs either after the initial colonization of a newly created habitat, or after a disturbance substantially alters a pre-existing habitat. Succession that begins in new habitats, uninfluenced by pre-existing communities, is called primary succession, whereas succession that follows disruption of a pre-existing community is called secondary succession.
GlacierA glacier (USpronˈɡleɪʃər; UKˈɡlæsiər,_ˈgleɪsiər) is a persistent body of dense ice that is constantly moving under its own weight. A glacier forms where the accumulation of snow exceeds its ablation over many years, often centuries. It acquires distinguishing features, such as crevasses and seracs, as it slowly flows and deforms under stresses induced by its weight. As it moves, it abrades rock and debris from its substrate to create landforms such as cirques, moraines, or fjords.
Species distributionSpecies distribution, or species dispersion, is the manner in which a biological taxon is spatially arranged. The geographic limits of a particular taxon's distribution is its range, often represented as shaded areas on a map. Patterns of distribution change depending on the scale at which they are viewed, from the arrangement of individuals within a small family unit, to patterns within a population, or the distribution of the entire species as a whole (range).
Fagus sylvaticaFagus sylvatica, the European beech or common beech is a deciduous tree belonging to the beech family Fagaceae. Fagus sylvatica is a large tree, capable of reaching heights of up to tall and trunk diameter, though more typically tall and up to trunk diameter. A 10-year-old sapling will stand about tall. It has a typical lifespan of 150–200 years, though sometimes up to 300 years. In cultivated forest stands trees are normally harvested at 80–120 years of age. 30 years are needed to attain full maturity (as compared to 40 for American beech).
Internal migrationInternal migration or domestic migration is human migration within a country. Internal migration tends to be travel for education and for economic improvement or because of a natural disaster or civil disturbance, though a study based on the full formal economy of the United States found that the median post-move rise in income was only 1%. Cross-border migration often occurs for political or economic reasons. A general trend of movement from rural to urban areas, in a process described as urbanisation, has also produced a form of internal migration.
Net migration rateThe net migration rate is the difference between the number of immigrants (people coming into an area) and the number of emigrants (people leaving an area) divided by the population. When the number of immigrants is larger than the number of emigrants, a positive net migration rate occurs. A positive net migration rate indicates that there are more people entering than leaving an area. When more emigrate from a country, the result is a negative net migration rate, meaning that more people are leaving than entering the area.
