Betydelsen av historiska miljöförhållanden för ändringar i samhällsstruktur i rum och tid
Tidsperiod: 2015-01-01 till 2018-12-31
Budget: 4 000 000 SEK
The composition of communities differs across space due to a combination of different processes, which include selection by local environmental conditions, dispersal from the regional species pool and stochastic events. However, these processes act at different time scales and thus historical events, such as past environmental conditions and past dispersal events may leave their imprint on communities. One major limitation is that most studies are "snap-shots" in time so that we currently know little about the importance of "the legacy of the past", in particular that of past environmental conditions, despite recent indications that they are important. Generally, effects of historical environmental conditions are difficult to address when slow growing larger organisms are used. This project will therefore make use of the advantages that natural bacterial communities offer with regard to the implementation of time-series studies and multi-generational experiments. The main hypothesis that will be tested is that effects of past environmental conditions are permanent due to priority effects when dispersal rates are low and when environmental conditions fluctuate strongly, whereas they are transient due to time-lags in species sorting when dispersal rates are sufficient and environmental conditions more stable. This study will be the first one to systematically test how past environmental conditions influence metacommunity dynamics.