XXVIII.-Local Changes in Distribution
| Autor: | T. G. Longstaff |
|---|---|
| Rok vydání: | 2008 |
| Předmět: |
education.field_of_study
Ecology business.industry media_common.quotation_subject Population Distribution (economics) Ecological succession Vegetation Biology Variable (computer science) Variation (linguistics) Ebb and flow Animal Science and Zoology Habit education business Ecology Evolution Behavior and Systematics media_common |
| Zdroj: | Ibis. 68:637-656 |
| ISSN: | 0019-1019 |
| DOI: | 10.1111/j.1474-919x.1926.tb05631.x |
| Popis: | Summary and Conclusions Evidence has been given as to the rapidity with which changes in the numbers and species the bird population may be produced by changing the type of vegetation on a small isolated site, and by the more direct interference of man. As a check to this, observations have also been recorded as to the effects on numbers of. good and bad weather, and also of the variation, from other causes unknown, in the annual numbers of certain migrants. It would appear that the ecological rather than the variable weather elements are the most weighty factor in their effect on species, while seasonal (and possibly periodic) weather variations temporarily exert greater influence on numbers. Distribution, which is merely a term of migration, is shown to be not fixed, but in numbers is swayed by recur-ring pulsations of ebb and flow, and in composition by local succession and supersession of species. These phenomena must ultimately depend on food-supply, and when the evolution of climate * with all its inevitable effects on biotic environment is considered, it appears probable that only through ecological research we can ever hope to attain a true conception of the laws of distribution and of the correlated habit of migration. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Plný text