| || || Platymantis -- Fiji -- Viti Levu -- Geographical distribution|
| || || Distribution, abundance and phenology of the Fiji tree frog (Platymantis vitiensis) in Savura, Viti Levu, Fiji|
Author: Osborne, Tamara
Institution: University of the South Pacific.
Subject: Hylidae -- Fiji -- Viti Levu -- Geographical distribution, Platymantis -- Fiji -- Viti Levu -- Geographical distribution, Frogs -- Fiji -- Viti Levu
Call No.: Pac QL 668 .E24 O83 2006
Copyright:10-20% of this thesis may be copied without the authors written permission
Abstract: Macro-habitat and microhabitat preferences of the Fiji tree frog, Platymantis vitiensis, were investigated in the Savura population near Suva, Viti Levu, Fiji. Twelve sites in three habitat types (primary lowland rainforest, disturbed secondary lowland rainforest, and mahogany plantations) were surveyed over a twelve-month period. In addition, phenology of the tree frog was investigated along two permanent transects along Vago Creek, Savura. Fiji tree frogs were more common in primary lowland rainforest sites than mahogany plantations and disturbed secondary lowland rainforest sites. The frogs are found more often along stream sides with Pandanus present, in relatively undisturbed rainforest. Frogs were more common along streams in the Colo-i-Suva mahogany reserve than the secondary forests and shrub land of the Vago and Savura reserves. The difference in frog abundance in these habitats is possibly due to human disturbance, although this was not examined. Tree frogs selected perch sites based on their height above ground, proximity within open riparian habitat strips, and the plant substrate’s features. Individuals were commonly found on Pandanus leaves and fern fronds, as well as the broad-leaved Dilenia. They were often captured close to the stream on riparian vegetation. The tree frogs were generally found one to two metres above the ground, and cohorts were observed in different microhabitats. The phenology of the Vago Creek frog population may be complicated by the inter-annual fluctuations in rainfall, and other factors such as migration and recruitment. The activity of adult frogs was significantly negatively influenced by rainfall; however gravid female abundance was significantly more correlated with changes in air temperature over the year than rainfall. Gravid females were more active during the wet season and egg-laying primarily occurred during the months of November to February. Juvenile tree frog phenology contrasts with metamorph Abstract xi activity, as metamorphs were captured more often during the dry season, whereas juvenile activity peaked early in the wet season. Rainfall was the most important weather variable influencing Fiji tree frog activity during the 12-month survey period, as indicated by independent tests of the broad-scale survey data. Although, Platymantis vitiensis populations in Savura were more abundant in primary lowland rainforest future surveys should also include secondary vegetation. Time-restricted surveys may be more effective by sub-sampling along riparian strips in primary forested areas, as tree frogs showed a strong affinity for stream-side perch sites. Future inventorying and monitoring of Fiji tree frog populations should be carried out when abundance is highest between late wet season, to early dry season (March to July).