• The effect of rainfall upon the behaviour and use of under-road culverts in four amphibian species

      Gleeson, Timothy; Petrovan, Silviu; Muir, Anna P.; University of Chester (Oxford Academic, 2019-04-29)
      Habitat fragmentation and road mortalities are major contributors towards declines in amphibian populations. This has seen the introduction of culverts, passages that run under roads and provide safe passage for amphibians. Research investigating the effects of rainfall upon amphibian culvert use is limited. This study, conducted at Frankfield Loch in Glasgow, assesses how time elapsed since rainfall influences migration behaviour and the use of culverts across four different species; common toads (Bufo bufo), common frogs (Rana temporaria and newts, a group composed of smooth newts (Lissotriton vulgaris) and palmate newts (Lissotriton helveticus). Analysis of images taken by a custom made, time lapse camera found that significantly fewer common toads (r = 0.148, n = 468, p = 0.001) and common frogs (r = −0.175, n = 106, p = 0.037) used the culvert as time since rainfall increased. This may have been caused by the culvert not maintaining wet enough conditions for amphi- bians. The study also found that more newts (r = 0.272, n = 92, p = 0.004) and common toads (r = 0.531, n = 19, p = 0.010) were using the culvert to move away from Frankfield Loch as time since rainfall increased. An increase in juvenile newts was also observed as time since rainfall increased (r = 0.214, n = 92, p = 0.020). This may have been caused by a decrease in baro- metric pressure, which follows a decrease in rainfall, acting as a cue for migration and juvenile dispersal. The study recom- mends careful consideration of the design of each culvert, incorporating species-specific preferences and the requirements of juveniles. The study also suggests that where possible the culvert should be designed to hold water for longer.