ISLAND POPULATIONS OF RODENTS: THEIR ORGANIZATION AND FUNCTIONING

摘要: Summary 1. Data from 14 confined populations living under natural conditions (mainly on small islands) and a few laboratory have been used. 2. Several differences between typical, rodent population (i.e. in well isolated, homogeneous relatively area) an open one determined. 3. Island are characterized by: (a) Attainment maintenance of high densities not observed at all, or recorded only periodically, comparable species. (b) Stability numbers, expressed either by very slight fluctuations regular cycle with peaks consecutive years. (c) Lack emigration resulting any all the barriers surrounding population, homogeneity habitat enclosed these barriers, lower tendency to dispersal individuals forming such populations. (d) Decreased reproduction. (e) Low losses independent individuals. (f) Mortality sucklings changing density. (g) An age structure that is probably more differentiated regularly annual long-term cycle. (h) Different spatial organization based smaller home ranges, differently arranged relation another those populations; arrangement ranges allows squeeze greater number possibly lowest interactions individuals. 4. In there must be different mechanisms for regulation numbers populations: (I) latter occurs outflow surplus individuals, i.e. through mortality migrants; (2) inflow regulated controlled reproduction early offspring. Both induced social pressure but second case (regulation inflow) much stronger indispensable Only species capable formation can survive as populations. 5. Knowledge phenomena occurring useful predicting fate which become isolated result human activity transforming subdividing environment.