Reproductive Phenology, Population Structure, and Habitat Use of the Frog Eleutherodactylus johnstonei in Barbados, West Indies

Abstract

-I report on population structure, growth, reproduction, and use of retreats by an abundant but poorly-known terrestrial frog, Eleutherodactylus johnstonei, in two contrasting habitats in Barbados, West Indies. A population inhabiting a forest site exhibited early maturity, small adult body size, short residency time, high juvenile to adult ratio, and low density, when compared to a population inhabiting an untended flower bed. At both sites, reproduction peaked in the early part of the wet season (JuneAugust), but males called about a month later in the flower bed site. Most growth took place during the wet season, and growth rates did not differ between sites. I suggest that both quality and quantity of retreat sites and the length of time available for activity are key factors in shaping life history characteristics of E. johnstonei at these sites. urnal of Herpetology, Vol. 25, No. 4, pp. 424-430, 1991 yright 1991 Society for the Study of Amphibians and Reptiles roductive Phenology, Population St ucture, and Habitat Use of e Frog Eleutherodactylus joh stonei in Barbados, W t Indies Eleutherodactylus johnstonei is a widespread and abundant neotropical species, native to several islands in the Lesser Antilles (Schwartz, 1967, 1978; Hardy and Harris, 1979). It commonly inhabits disturbed areas but also occurs in mesic, mature forests (Schwartz, 1967). Stewart (1979) and Stewart and Martin (1980) examined the role of introduced Eleutherodactylus (including E. johnstonei) in anuran communities in Jamaica, but life history of E. johnstonei in the Lesser Antilles is poorly known. Bayley (1950) studied its natural history, and Lemon (1971) investigated spacing of calling males in Barbados. Here I report on population structure, reproductive phenology, growth, and habitat use by 'Present Address: Department of Zoology, The University of British Columbia, Vancouver, B.C., Canada V6T 1W5. leutherodactylus johnstonei is a widespread and ndant neotropical species, na iv to several lands in the L sser Antilles (Schwartz 1967, 78; Hardy and Harris, 1979). It c mmonly inE. johnstonei in two habitats in Barbados, where the species is probably indigenous (Marsh, 1982; but see Schwartz, 1967). My objective was to examine intraspecific variation between populations occupying contrasting habitats. One study site was in a flower bed, and the other site was in a mature forest along a seasonallyactive stream. Based on the abundance of potential retreat sites due to the dense ground vegetation in the flower bed, I predicted that it would support a greater density of frogs with higher individual growth rates and a longer breeding season than the forested site.