Original paper

Microhabitat and morphological variation in fresh water Blennothrix ganeshii (Oscillatoriaceae, Cyanophyceae) populations in streams of central Mexico

Beltrán-Magos, Yenny; Carmona, Javier; Vilaclara, Gloria


Microhabitat was investigated in four populations of B. ganeshii in calcareous tropical streams in central Mexico to determine the distributional patterns and some of their controlling factors, as well as morphometric adaptations to varying conditions on scales of a few centimetres. Morphometric variations and their relation to physical variables (current velocity, depth, irradiance, and type of substratum) revealed some characteristics for each population and indicated particular adaptations: current velocity was negatively correlated with filament length, filament diameter and trichome width; irradiance was positively correlated with filament diameter and trichome width, number of false branches in a filament and percent cover; and predominant substratum was positively correlated with filament length and sheath thickness. The information here reported about the ecological distribution of B. ganeshii supplements the taxonomic knowledge with data about its environmental requirements, which are important for the taxonomy of the genus. Variations in microhabitat conditions and niche widths are the main contributors to the wide spatial and seasonal distribution of this Oscillatorian in central Mexican streams.


blennothrixcentral mexicocyanobacteriacyanophyceaeionic compositioncurrent velocityirradiancemicrohabitatmorphometric variationstreams