Pěnovcová slatiniště jsou unikátním typem lučních mokřadů, které ve svých sedimentech (slatině nebo vysráženém uhličitanu vápenatém) zachovávají zbytky hned několika skupin organismů. Především jsou to schránky měkkýšů, pyl a makrozbytky rostlin, ale také mikroorganismy. Můžeme proto na tato izolovaná a často refugiální stanoviště nahlížet jako na přírodní archivy, jejichž studium nám umožňuje pohlédnout do historie vývoje slatiništní bioty a také řešit mnoho zajímavých otázek.

On the basis of the long-term research of plant and mollusc assemblages in more than 170 isolated fen sites in the Western Carpathians we observed a sharp gradient of species turnover spans from west to east. These differences were mainly in the distribution of so-called relict species and were independent on any ecological difference among studied fens. Our extensive palaeoecological research using fossil evidence and radiocarbon dating confirmed that sites in the outer flysch part (e.g. border area between Czech and Slovak Republics in the west) are much younger than those located in the Inner Western Carpathians and they host many relict species and have a Holocene continuity (maximum age was nearly 17 thousands calibrated years before present). Using null model we statistically confirmed that several presumable relict species are, as expected, statistically significantly related to old sites that originated during the Pleistocene/Holocene boundary. This result was statistically significant even if the test was controlled for the effect of habitat area.