%0 Journal Article %1 wzlidicker1962colonization %A W. Z. Lidicker, P. K. Anderson %D 1962 %I Wiley, British Ecological Society %J Journal of Animal Ecology %K Microtus colonization island_adaptation population_dynamics population_growth %N 3 %P 503-517 %T Colonization of an Island by Microtus californicus, Analysed on the Basis of Runway Transects %U http://www.jstor.org/stable/2050 %V 31 %X 1. The dispersal and population growth resulting from an invasion of Microtus californicus into an island free of voles were studied by analysing the vole runways intersecting three transects. Observations ran from the time of invasion in the summer of 1958 to May 1960. 2. The population increased when green vegetation was available, and decreased in dry periods. 3. Although the whole island (47 acres) was invaded by voles during the first growing season, it was not fully exploited until the second summer. 4. After June 1959 the relative densities of population on the three transects remained constant. This suggests that June 1959 marked the transition from colonization to exploitation. 5. Emigrating voles apparently responded continuously to economic density, moving out into more favourable areas before the currently inhabited area was fully exploited. The relative densities developed matched the gradient in habitat favourability; the population showed greater seasonal variability in poorer habitats. 6. Specific rates of increase in runway densities did not differ in the two seasons of growth. In the second season growth-rates were highest in the poorest habitat which had the lowest initial density, and lowest in the best habitat with the highest initial density. There was no evidence of declining growth-rates at high densities. 7. The life of individual runways varied from <4 to >100 weeks; the average for a cohort of ninety-five runways was 22.3 weeks. 8. Many short-lived runways were built in relatively poor areas during population peaks; they were abandoned sooner in the dry season than when the vegetation was growing. 9. First arrivals in an uninhabited area build runways at random but stable patterns reflecting the quality of micro-habitats develop as exploitation continues. 10. Runways in use for 36 or more weeks tend to be more clumped in the better habitats and less clumped in the poorer, although none were significantly non-random in arrangement. No evidence of even spacing (infra-dispersion) could be detected.

@article{wzlidicker1962colonization, abstract = {1. The dispersal and population growth resulting from an invasion of Microtus californicus into an island free of voles were studied by analysing the vole runways intersecting three transects. Observations ran from the time of invasion in the summer of 1958 to May 1960. 2. The population increased when green vegetation was available, and decreased in dry periods. 3. Although the whole island (47 acres) was invaded by voles during the first growing season, it was not fully exploited until the second summer. 4. After June 1959 the relative densities of population on the three transects remained constant. This suggests that June 1959 marked the transition from colonization to exploitation. 5. Emigrating voles apparently responded continuously to economic density, moving out into more favourable areas before the currently inhabited area was fully exploited. The relative densities developed matched the gradient in habitat favourability; the population showed greater seasonal variability in poorer habitats. 6. Specific rates of increase in runway densities did not differ in the two seasons of growth. In the second season growth-rates were highest in the poorest habitat which had the lowest initial density, and lowest in the best habitat with the highest initial density. There was no evidence of declining growth-rates at high densities. 7. The life of individual runways varied from <4 to >100 weeks; the average for a cohort of ninety-five runways was 22.3 weeks. 8. Many short-lived runways were built in relatively poor areas during population peaks; they were abandoned sooner in the dry season than when the vegetation was growing. 9. First arrivals in an uninhabited area build runways at random but stable patterns reflecting the quality of micro-habitats develop as exploitation continues. 10. Runways in use for 36 or more weeks tend to be more clumped in the better habitats and less clumped in the poorer, although none were significantly non-random in arrangement. No evidence of even spacing (infra-dispersion) could be detected.}, added-at = {2016-03-18T01:05:33.000+0100}, author = {W. Z. Lidicker, P. K. Anderson}, biburl = {https://www.bibsonomy.org/bibtex/2478609f36d206dcb0614e8407d34c7d7/peter.ralph}, interhash = {ae4f8e987fdfbdd3bf567a71a4b9bfd6}, intrahash = {478609f36d206dcb0614e8407d34c7d7}, issn = {00218790, 13652656}, journal = {Journal of Animal Ecology}, keywords = {Microtus colonization island_adaptation population_dynamics population_growth}, number = 3, pages = {503-517}, publisher = {[Wiley, British Ecological Society]}, timestamp = {2016-03-18T01:05:33.000+0100}, title = {Colonization of an Island by Microtus californicus, Analysed on the Basis of Runway Transects}, url = {http://www.jstor.org/stable/2050}, volume = 31, year = 1962 }