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Title (Primary) Compensatory versus over-compensatory density regulation: implications for metapopulation persistence in dynamic landscapes
Author Münkemüller, T.; Johst, K.;
Journal Ecological Modelling
Year 2006
Department OESA;
Volume 197
Issue 1-2
Language englisch;
Abstract An important determinant of local population growth is the strength of density regulation resulting from intraspecific competition. Using a simulation model, it was analysed how density regulation interacts with dispersal properties (composed of density-dependent emigration, dispersal range and mortality) and landscape dynamics (patch destruction and regeneration) to affect the persistence of metapopulations. The results show that the complex interactions between intraspecific density regulation, dispersal and landscape dynamics do not allow for general conclusions for each of these factors. Therefore, a concept of connectivity which combines species and landscape attributes is used. To interpret the modelling results it was necessary to extend this concept considering two aspects: (1) the strength of connectivity determined by the mean number of immigrants (amplified by high emigration rates, low dispersal mortality and low landscape dynamics) and (2) the heterogeneity of connectivity determined by the spatio-temporal variability of immigration (enhanced by short-range dispersal, density-dependent emigration and landscape dynamics). Strong and homogeneous connectivity results in strong synchronization of local dynamics but allows for efficient colonization, whereas weak and heterogeneous connectivity has the reverse effects. It was found that metapopulations with compensatory density regulation always profit from strong and homogeneous connectivity. In contrast, metapopulations with strong over-compensatory density regulation have an intrinsically high local extinction risk due to their complex dynamics and therefore require both high colonization and low synchronization. Thus, they suffer from a combination of strong and homogeneous as well as weak and heterogeneous connectivity. In conclusion, the study suggests that conservation plans for metapopulations should consider the impact of the management strategies on the strength and heterogeneity of the connectivity pattern with respect to the mode of intraspecific competition of the target species. The establishment of dispersal corridors, stepping stones or a decrease in landscape dynamics are likely to be advantageous for species with compensatory density regulation but may be detrimental to species with over-compensatory density regulation.
ID 2886
Persistent UFZ Identifier http://www.ufz.de/index.php?en=20939&ufzPublicationIdentifier=2886
Münkemüller, T., Johst, K. (2006):
Compensatory versus over-compensatory density regulation: implications for metapopulation persistence in dynamic landscapes
Ecol. Model. 197 (1-2), 171 - 178