Keywords
tree species migration, spatially linked dynamic model, species parameter uncertainty, treemig
Start Date
1-7-2012 12:00 AM
Abstract
The simulation of tree species migration suffers from many sources of uncertainty.In our study we examined the influence of species parameter uncertainty on simulatedtree species migration, using the spatially linked dynamic forest landscape modelTreeMig. The impact of uncertainty becomes especially apparent under critical conditionsarising from the interaction of species sensitivities to climate, species competitionand spatial fragmentation. Therefore we examined the differences in migration successand speed in a realistic scenario including these critical conditions. The south-north migrationof the submediterranean tree species Ostrya carpinifolia through the highly fragmentedand climatically heterogeneous landscape of the Swiss Alps was simulated for27 different species parameter sets covering the plausible range of species parametersfor O. carpinifolia. To account for the additional uncertainty introduced by the stochasticrepresentation of future climate variability, each species parameter set was simulatedwith multiple repetitions. We found that migration success and speed resulting from simulationswith the different sets varied highly. The current situation of rapid climate changeand high landscape fragmentation due to human land use could create critical conditionscomparable to the simulated scenario for various species. We therefore recommendtesting for species parameter sensitivities and – if indicated – to repeat simulations withdifferent parameter sets when projecting future tree species distributions with explicitsimulation of migration.
Impact of Species Parameter Uncertainty in Simulations of Tree Species Migration with a Spatially Linked Dynamic Model
The simulation of tree species migration suffers from many sources of uncertainty.In our study we examined the influence of species parameter uncertainty on simulatedtree species migration, using the spatially linked dynamic forest landscape modelTreeMig. The impact of uncertainty becomes especially apparent under critical conditionsarising from the interaction of species sensitivities to climate, species competitionand spatial fragmentation. Therefore we examined the differences in migration successand speed in a realistic scenario including these critical conditions. The south-north migrationof the submediterranean tree species Ostrya carpinifolia through the highly fragmentedand climatically heterogeneous landscape of the Swiss Alps was simulated for27 different species parameter sets covering the plausible range of species parametersfor O. carpinifolia. To account for the additional uncertainty introduced by the stochasticrepresentation of future climate variability, each species parameter set was simulatedwith multiple repetitions. We found that migration success and speed resulting from simulationswith the different sets varied highly. The current situation of rapid climate changeand high landscape fragmentation due to human land use could create critical conditionscomparable to the simulated scenario for various species. We therefore recommendtesting for species parameter sensitivities and – if indicated – to repeat simulations withdifferent parameter sets when projecting future tree species distributions with explicitsimulation of migration.
