Spatial ecology of the Concho water snake (Nerodia harteri paucimaculata) in a large lake system


The distribution, movements, activity range, and habitat use of the Concho water snake, Nerodia harteri paucimaculata, were studied by mark-recapture and radio telemetry in a large lake system, in central Texas, USA. Concho water snake emigration and distribution were largely driven by alteration of habitat availability caused by fluctuating water levels. Habitat characteristics associated with the presence of snakes at the study area were turbid water, minimal wave action, a gentle shoreline gradient, a silt substrate, and a rocky shoreline. Males and gravid females were equally vagile, and the likelihood of a snake undertaking an emigrational movement was independent of age and/or reproductive condition. However, males had significantly more movement days than gravid females. Radio-tagged males had detectable movements on 64% of monitored days, compared to 43% of monitored days for gravid females. Mean activity range length was 278 m for males, 219 m for gravid females, and 210 m for juveniles. Concho water snakes generally selected retreat sites within 3 m of water, although gravid females selected sites as far as 15 m from water. As a management procedure for lake populations, we advocate increasing the vertical distribution of rocky shoreline.

Document Type



Publication Date


Journal Title

Journal of Herpetology