Tracking Ceratophrys ornata: a Telemetry-based Study on a Vulnerable Amphibian Species and its Conservation Implications

Abstract

The Argentinean Horned Frog (Ceratophrys ornata) is a vulnerable amphibian from the Pampas experiencing population decline. We assessed the spatial ecology in Buenos Aires Province, Argentina, during three breeding seasons (2019–2022). We fitted 37 adults with radio transmitters, recording daily locations, meteorological variables, and microhabitat characteristics. We tracked individuals during reproductively active (RAP) and inactive (RIP) periods. We estimated home ranges using the Minimum Convex Polygon and compared daily movement rates between periods and sexes. We explored the influence of meteorological variables on movement patterns using Generalized Estimating Equations. Finally, we characterized microhabitat and assessed habitat use and selection employing land use/cover layers. Ceratophrys ornata had a median home range of 5,800 m2 during the RAP (range of values, 500–32,100 m2 , n = 11) and 660 m2 during the RIP (23–9,320 m2, n = 18). Median daily movement rates were significantly higher during the RAP (43.2 m/d, range of values, 7.7–106.7 m/d, n = 11) than the RIP (1.7 m/d, 0.3–8.7 m/d, n = 18). The probability of movement was significantly (P < 0.05) and positively associated with relative humidity and 5-d accumulated precipitation. Microhabitats for RAP and RIP shared similar vegetation structure but were located in different sites/substrates (ground and water). At habitat scale, individuals used grasslands and flooded grasslands. Ceratophrys ornata required < 4 ha for ssential activities (foraging, sheltering, reproduction) and shallow flooded grasslands with dense vegetation and diverse native grasses. These findings provide the basis for in situ/ex situ actions to conserve remnant populations of C. ornata