Investigating habitat suitability of Keyvan spined loach, Cobitis keyvani Mousavi-Sabet et al., 2012 in Totkabon River (Sefidroud river basin) using generalized additive models (GAM)

In order to protect the biodiversity of riverine ecosystems, understanding the biological requirements of aquatics is essential. Therefore, this study was conducted to investigate the habitat suitability of Keyvan spined loach, (C. keyvani) in its distribution range within Totkabon River using generalized additive models (GAMs). To study the habitat characteristics of this species, frequency and six habitat variables including elevation (m), depth (cm), river width (m), flow velocity (m/s), average diameter of substrate stones (cm) and substrate index (%SI) were measured at 16 stations from the downstream to upstream. Continuous data were analyzed in Moped software based on GAM model and Poisson distribution. In the obtained model, bed index, river width, flow velocity and elevation above sea level in all combinations were significant. Elevation, water velocity, and bed index were inversely correlated and river width showed a direct relationship with frequency of spiny loach. Based on the results, the habitat suitability of Keyvan spined loach is regions with high-velocity, sandy-clay bed (due to deposition of suspended sediment), with higher width and low elevation and depth.