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Surveys were distributed to New Zealand land users in 1998 and 2008 to acquire information about New Zealand frogs with the aim of compiling and mapping their distribution and inferred population trends without costly and time-consuming field surveys. The overall frog population trend was reported as declining, with possible causes reported as an increase in agriculture, an increase in the distribution of predatory fish and disease. The resultant maps could be used for four main purposes: 1) to identify regions where Litoriapopulations are known to occur, which can be eliminated when considering suitable regions for translocation of Leiopelma; 2) to identify growing or stable populations of Litoriaspecies, which may assist future disease surveys, population monitoring and to identify sources of genetic material that may serve as an Ark for declining Australian populations; 3) to highlight populations that are in decline to enable effective targeting of detailed disease studies; and 4) to approximate the stability of amphibian populations in the absence of more accurate, but costly, scientific monitoring.

AbstractThe secretion of defensive chemicals onto the skin is a widely used mechanism for predator defence in anurans. Secretions often consist of a mixture of bioactive peptides with cytotoxic or neurotoxic effects. In New Zealand, introduced rodents have been suggested as main drivers for declines and extinctions of endemic frogs. We demonstrate the efficacy of Leiopelma pakekasecretions in deterring rats (Rattus norvegicusLong-Evans) from ingesting secretion-covered food and showed that they can successfully lyse rat erythrocytes. When offered a choice, rats displayed a significant preference for food pellets coated with water over those covered in frog secretions. Direct oral exposure to the secretions has no significant effects on water or food intake of rats. Video analysis showed no significant difference in the proportion of time rats spent grooming, rising on hind legs, motionless or investigating associated with exposure to the secretions. This study provides new insight into the defensive function of leiopelmatid skin secretions.

AbstractDiets for captive amphibians are often inadequate and lead to poor health. To determine the natural diet of two New Zealand frog species, we analysed the stomach contents of 16 Archey's frogs (Leiopelma archeyi) from the Moehau Range of the Coromandel Peninsula and nine Hochstetter's frogs (Leiopelma hochstetteri) from the Moehau Range of the Coromandel Peninsula, the Hunua Ranges and Maungatautari. These specimens were obtained as by-catch from invertebrate pitfall traps from 2002 to 2008. Both species ate a wide range of invertebrates including springtails, mites, ants, parasitic wasps, amphipods and isopods. Leiopelma archeyialso ate snails. The mean ratio of maximum prey size ingested to snout–vent length in L. archeyiwas 0.31 (range 0.16–0.5), and in L. hochstetteriwas 0.42 (range 0.21–0.75). We suggest a reformulated captive diet based on the species and size of invertebrates ingested in the wild. This diet may assist in the prevention of metabolic bone disease.

New Zealand's endemic leiopelmatid frogs are all threatened with extinction. There is no obvious physical or behavioural difference between males and females of three of the four species and this lack of a sex identification technique is hindering conservation management. Twenty-one morphological features were measured for 67 live Leiopelma pakeka of known sex to determine whether a slight morphological difference existed that could be used for sex identification. Females were significantly longer in snout-to-vent length (SVL) than males, but as a great deal of overlap exists between sexes, this is not an ideal sex identification trait. No other physical characteristic was significantly different between sexes when adjusted for SVL. Discriminant analysis using a suite of traits was also unable to discriminate between sexes for frogs in the male-female overlap size range. The measurement of physical characteristics is inadequate for identifying sex in L.pakeka and other methods for sex identification must be developed. The reasons for the lack of sexual difference are unknown.