Competition for open space

• Main Authors: Shigesada, Nanako, Kawasaki, Kohkichi
• Format: Book Part
• Language: unknown
• Published: Oxford University PressOxford 1997
• Subjects: Tundra
• Online Access: http://dx.doi.org/10.1093/oso/9780198548522.003.0007; https://academic.oup.com/book/chapter-pdf/52520356/isbn-9780198548522-book-part-7.pdf

Abstract An open space, to an organism, can be defined as 'a space which when invaded will allow reproductive growth'. According to this definition, a new continent to an invading species from another continent could constitute a large open space. Likewise, freshly deglaciated grounds that appeared after the retreat of ice-sheets in the northern hemisphere during the Quaternary Period were also large open spaces. By analyzing the fossil pollen record taken from lake sediments, Davis (1981) showed that the open space (tundra) that appeared in North America after the last ice age (16,000 years ago) was consecutively invaded from the southeast by spruce (Picea), oak (Quercus), white pine (Pinus), hemlock (Tsuga), beech (Fagus) and somewhat later chestnut (Castanea dentata), etc., and that each took a different route, advancing its range northward or westward at the rate of about 100-400 m/year (Fig. 7.1; see also Bennett, 1983, 1986; Jacobson et al., 1987). One of the most rapid migrants among them is oak (350 m/year), although the acorns from a parent oak are disseminated usually by only a few metres per year.