Ardea
Official journal of the Netherlands Ornithologists' Union

login


[close window] [previous abstract] [next abstract]

Cuperus R. & de Bruyn G.J. (1987) Statistical impacts of the detection of natural regulation in bird populations on account of census data. ARDEA 75 (2): 237-243
To illustrate some statistical problems with which investigators are faced in research on population dynamics, two tests for detecting regulation (density dependence) were applied to censuses of bird territories in parts of a dune area Meijendel (Zuid-Holland) and an inland wood Mastbos (Noord-Brabant) in The Netherlands. Application of the tests to the Meijendel time series resulted in a low number of bird species for which a statistically significant regulation could be established, due to the presence of positive and negative trends in the greater part of the censuses. On the other hand, density-independent immigration in populations could be responsible for the high percentage of positive regulation decisions connected with the Mastbos time series. Correct regulation detection is hampered by the presence of pronounced trends in censuses and the contribution of density-independent immigration to the censuses, and also by a certain degree of interdependence between successive data. Therefore, the application of the regulation tests to the bird censuses appeared to be a procedure of limited value.


[close window] [previous abstract] [next abstract]