@misc{Szwagrzyk_Jerzy_Rola_2002, author={Szwagrzyk, Jerzy}, editor={Polska Akademia Nauk. Instytut Ekologii}, copyright={Creative Commons Attribution BY 3.0 PL license}, address={Dziekanów Leśny}, howpublished={online}, year={2002}, language={pol}, abstract={A hidden assumption that plants in generał, and trees in particular, are not significantly limited by their dispersal abilities persisted for a long time in ecological literaturę, and especially in papers concerning plant succession. The older models of forest dynamics (like JABOWA or FORET) usually assumed, that all species present in a regional species pool are also present in each simulated forest patch. However, in recent years there has been an increasing evidence which supports the opposite view - that dispersal abilities of trees strongly influence their population dynamics. A commonly observed trade-off between the competitive ability and mean dispersal distance can be considered one of the main mechanisms preventing exclusion of competitively weaker species and maintaining tree species diversity in forest stands. The morę recent models of forest dynamics (like SORTIE) tend to include the dispersal limitations into their theoretical framework. However, quantitative analysis and modelling of spatial distribution of seeds is a complicated task. The spatial distribution of seed densities around the stem of a parent tree - so- -called ”seed shadows” - used to be modelled by employing several dispersal functions (like log-normal, exponential, etc.). However, these functions were unable to simulate the dispersal of a smali fraction of seeds at very large distances. Recently, the so-called ”fat-tailed” distributions are being used for a morę realistic modelling of seed dispersal. They allow a smali fraction of seeds to be transported at very large distances, despite the fact, that majority of seeds fali close to the stem of the parent tree. The ”fat-tailed” distributions has been also employed in analyzing the patterns of tree migrations during the Holocene. Using the fat-tailed distributions allows to simulate tree migration in a morę realistic way and to overcome the so-called Reid*s paradox; that the actual rates of tree migration were several times higher than the estimates based upon the so-called ”ecological step”. The results of employing "fat-tailed” distributions for modelling tree migrations are intriguing: among them are the exponential increase of the ratę of population spread, and the fact, that species distributions are in most cases not uniform, but consist of several larger or smaller patches, as well as "islands" located far beyond the limits of the main area of a given species.}, type={Text}, title={Rola rozprzestrzeniania diaspor w dynamice ekosystemów leśnych}, URL={http://www.rcin.org.pl/Content/229275/WA058_173778_P3259-48_Eko-Pol-B.pdf}, volume={48}, number={3}, journal={Wiadomości Ekologiczne}, publisher={Oficyna Wydawnicza Instytut Ekologii PAN}, }