Hinweise auf die Wirksamkeit abiotischer Schlüsselfaktoren in Carabiden-Populationen : Erkenntnisse aus mehr- und vieljährigen Untersuchungen : Die Bedeutung ökologischer Langzeitforschung für Naturschutz

Indications of the efficacy of abiotic key factors in carabid populations

1998

32 Lit. Ang.

Unselbständiges Werk

12751

200080578

In the course of a 5 year investigation on the "habitatbindung" of carabid species in the Melico-Fagetum of the Teutoburger Wald (Lower Saxony) we observed largely synchronous fluctuations of the numbers of individuals trapped in several species. We hypothesized the efficacy of a key factor that influenced the adult survival probability and/or the reproduction rate in these species. The nature of the key factor remained unknown, though it was thought perhaps to be a climatic factor. During an investigation lasting 16 years in al local population of Carabus auronitens inhabiting the Stellario-Carpinetum in the Münsterland (Westphalia) we observed fluctuations in net reproduction rate which were positively correlated with the meteorological mean temperature in the 2nd ten days of May, partially also with that in the 1st ten days. Obviously, a temperature factor, probably the temperature of the ground surface and the soil near the surface, has been a key factor for net reproduction in this population. Evidently, then, key factors are effective even in carabid populations that occupy rather stable habitats. The phenomenon of natural fluctuations of abundance under the influence of key factors is relevant to the interpretation of data obtained for biotope evaluations and biomonitoring.