The effect of a summer wildfire on the abundance and community composition of soil macroinvertebrates of a phryganic ecosystem was studied. The numerical responses of macroinvertebrates to fire were variable, most notably the reduction of the saprophagous fauna. The magnitude of the changes in abundance due to fire was comparable or even lower than the variations imposed by the seasonality of the mediterranean climate. fire did not seem to affect strongly the community composition of the soil inhabiting fauna, but caused considerable changes in the composition of the litter-dwellers. Furthermore, seasonal changes in community composition were less pronounced in the burnt site compared to those in the control. The observed effects of fire should be attributed to the destruction of the litter layer and the above ground vegetation cover, rather than to the immediate death of the animals, since most of them were absent from the upper soil layers during summer, that is when fire occured.

Tzafestas, S. G. 2004. Population dynamics and life history tactics of arthropods from Mediterranean-type ecosystems. -Oikos 104: 98 -108.The null hypothesis of this paper is that survival of arthropods under the severe Mediterranean conditions involves specific combinations of conservative and conformist traits. To test this hypothesis a modeling approach employing a Leslie-type matrix model and a fuzzy systems technique for parameter estimation is developed and applied to a model species. The general conclusion is that the results of this paper add support to the null hypothesis, whereas specific conclusions are as follows: 1) matrix models merging demographic and physiological parameters are suitable tools for the simulation of population dynamics of arthropods and further for the discussion of the interplay among life history traits; 2) employing linguistic instead of arithmetic variables, fuzzy approaches allow for the formalization of incomplete and/or missing data exploiting expertise concerning related species; 3) in general, population dynamics of arthropods follow the seasonality of the Mediterranean climate; 4) the basic mechanism underlying skewing phenologies and stochastic equilibrium is identified with the type of temperature dependence of arthropod metabolic activity; 5) under optimal conditions an exponential trend is superimposed on seasonal population dynamics; 6) more realistic conditions involving large-scale random oscillation in temperature in autumn and spring coupled with small-scale temperature oscillation in summer and winter result in stochastic equilibrium; 7) moderate contamination of soil and medium-scale oscillation in temperature result in stable temporal patterns; 8) a sensitivity analysis shows disproportional effect of different demographic parameters on population growth rate. Fecundity of young and middle-aged adults is most important for the rate of population growth, whereas elder animals are considered an important pool for maintenance of the population.