Self-organizing maps of Kohonen as means of Chara and Nitella species distribution diagnostic

Abstract

Boszke P. and Astel A.M. 2010. Self-organizing maps of Kohonen as means of Chara and Nitella species distribution diagnostic. Phycologia 49: 592–603. DOI: 10.2216/09-72.1This study deals with the exploration of oospores morphometric variability according to various types of water reservoirs of Poland by the self-organizing maps (SOM). The SOM integrates morphometrical features in order to distinguish genera and species and to explore their natural environmental habitats. The data set covered 575 oospores collected in Poland and contained measurements of largest polar axis (LPA), largest equatorial diameter (LED), isopolarity index, number of ridges and width of fossa (WF) of 15 Chara and Nitella species. Biometric analysis of oospores revealed that Chara and Nitella genera could be easily distinguished by the SOM. LPA and LED of C. contraria oospores collected from lakes were higher than in case of those found in peat bogs. LPA, LED and WF of C. globularis that were found in lakes were higher than the ones of charophytes from ponds and ditches. The most taxonomically useful morphometrical features for oospores identification are LPA, LED and WF. The advantages of SOM algorithm in the form of exceptional visualization, dimension reduction and exploration abilities are stressed.