DefaunationDefaunation is the global, local, or functional extinction of animal populations or species from ecological communities. The growth of the human population, combined with advances in harvesting technologies, has led to more intense and efficient exploitation of the environment. This has resulted in the depletion of large vertebrates from ecological communities, creating what has been termed "empty forest". Defaunation differs from extinction; it includes both the disappearance of species and declines in abundance.
Seed libraryA seed library is an institution that lends or shares seed. It is distinguished from a seedbank in that the main purpose is not to store or hold germplasm or seeds against possible destruction, but to disseminate them to the public which preserves the shared plant varieties through propagation and further sharing of seed. The first contemporary seed library was created in 1999 at the Berkeley Ecology Center. It was called the Bay Area Seed Interchange Library (BASIL).
Threatened speciesThreatened species are any species (including animals, plants and fungi) which are vulnerable to extinction in the near future. Species that are threatened are sometimes characterised by the population dynamics measure of critical depensation, a mathematical measure of biomass related to population growth rate. This quantitative metric is one method of evaluating the degree of endangerment.
Christmas treeA Christmas tree is a decorated tree, usually an evergreen conifer, such as a spruce, pine or fir, or an artificial tree of similar appearance, associated with the celebration of Christmas. The tree was traditionally decorated with "roses made of colored paper, apples, wafers, tinsel, [and] sweetmeats". Moravian Christians began to illuminate Christmas trees with candles, which were often replaced by Christmas lights after the advent of electrification.
Dendroctonus rufipennisDendroctonus rufipennis, the spruce beetle, is a species of bark beetle native to British Columbia, Newfoundland and Labrador, Nova Scotia, Ontario, Quebec, Northern Manitoba, the Yukon, Colorado, Wyoming, Montana, and Maine. They are known to destroy forests of spruce trees including Engelmann, White, Sitka, and Colorado blue spruce. Adults average 4 to 7 mm in length. The spruce beetle Dendroctonus rufipennis Kirby (formerly D. obesus Mannerheim (== D. engelmanni Hopk.
Tree lineThe tree line is the edge of the habitat at which trees are capable of growing. It is found at high elevations and high latitudes. Beyond the tree line, trees cannot tolerate the environmental conditions (usually low temperatures, extreme snowpack, or associated lack of available moisture). The tree line is sometimes distinguished from a lower timberline, which is the line below which trees form a forest with a closed canopy. At the tree line, tree growth is often sparse, stunted, and deformed by wind and cold.
Competitive exclusion principleIn ecology, the competitive exclusion principle, sometimes referred to as Gause's law, is a proposition that two species which compete for the same limited resource cannot coexist at constant population values. When one species has even the slightest advantage over another, the one with the advantage will dominate in the long term. This leads either to the extinction of the weaker competitor or to an evolutionary or behavioral shift toward a different ecological niche.
Species PlantarumSpecies Plantarum (Latin for "The Species of Plants") is a book by Carl Linnaeus, originally published in 1753, which lists every species of plant known at the time, classified into genera. It is the first work to consistently apply binomial names and was the starting point for the naming of plants. Species Plantarum was published on 1 May 1753 by Laurentius Salvius in Stockholm, in two volumes. A second edition was published in 1762–1763, and a third edition in 1764, although this "scarcely differed" from the second.
Genetics and the Origin of SpeciesGenetics and the Origin of Species is a 1937 book by the Ukrainian-American evolutionary biologist Theodosius Dobzhansky. It is regarded as one of the most important works of modern synthesis and was one of the earliest. The book popularized the work of population genetics to other biologists and influenced their appreciation for the genetic basis of evolution. In his book, Dobzhansky applied the theoretical work of Sewall Wright (1889–1988) to the study of natural populations, allowing him to address evolutionary problems in a novel way during his time.
