Habitat (and essential habitat features)
The Growling Grass Frog (GGF) is a predominately aquatic species that inhabits freshwater habitats including ephemeral and permanent wetlands, lakes, swamps, ponds, dams, slow-flowing creeks, and artificial wetlands.
There are several features that must be present for a GGF population to thrive within an ecosystem.
The presence of emergent, floating, and submergent vegetation is an important determinant of the suitability of a GGF habitat. GGFs utilise these vegetation types for a variety of purposes. They provide refuge against predation for both adult and tadpoles, act as basking and hunting sites for adults, and are a major food source for tadpoles. Furthermore, emergent, floating, and submergent vegetation plays an important role in the reproductive cycle of the GGF, representing calling stages for males, and egg-laying sites for females.
To avoid predation, support the species overwintering behaviour, and to facilitate the safe dispersal of the species within a landscape, suitable refuge sites must be present. This includes adjacent grasslands, rocky outcrops, logs, cracks within soil, and emergent and riparian vegetation.
This includes submergent and floating vegetation, rocks, and logs. Basking is important for the health and development of the species and assists in the prevention and management of diseases and pathogens including chytridiomycosis.
Proximity of additional waterbodies
The interconnectedness and proximity of water bodies influences the success of a GGF population. To persist within a landscape a matrix of aquatic and terrestrial suitable habitats must be present, allowing the species to safely disperse.
During winter GGFs exhibit overwintering behaviour, becoming almost inactive, and seeking refuge under logs, rocks, within large cracks in the soils, and amongst dense grasslands and riparian vegetation.
The GGF is a generalist carnivore, actively hunting and feeding at night on a variety of prey types including invertebrates, smaller amphibian species including members of the same species, fish, small lizards, and tadpoles.
The GGF reproductive cycle takes place annually between November and March. This cycle begins with males performing mate calls and is triggered by heavy rainfall events, flooding, and the experienced increase in available water. If receptive to the mating calls, females will lay clutches of up to 4500 eggs onto submergent and floating vegetation. Tadpoles begin to hatch 2-4 days later and reach sexual maturity at 43 days for males, and 113 days for females.
GGFs are highly mobile and can naturally disperse 1-2km between aquatic and terrestrial habitats within a landscape. Furthermore, GGF populations within ephemeral systems display higher levels of dispersal when compared to populations that inhabit small, permanent waterbodies.