Genetic and phenotypic variation used to identify populations of endangered green gecko (Naultinus) found in the north-west South Island, New Zealand : a thesis submitted in fulfilment of the requirements for the degree of Master of Science in Conservation Biology, Massey University, Albany and Palmerston North. EMBARGOED until further notice.
Two species of green gecko (Naultinus stellatus and Naultinus tuberculatus) found in the north
and west South Island are endemic to New Zealand and are classified as Nationally
Vulnerable (Hitchmough et al. 2016). Detailed information about the ecology, morphology and
distribution of these geckos is limited, including what traits are diagnostic, details of their
geographic range and it is unknown whether both species hybridise in the wild. My research
aimed to investigate if the Denniston and Stockton Plateaus in New Zealand’s South Island
represent a putative contact zone between N. stellatus and N. tuberculatus and if natural
hybridisation occurs. Naultinus species are known to reproduce with each other in captivity
and a few wild caught individuals (n=5) have led to an inference of introgressive hybridisation.
In addition, I aimed to collect basic data on the ecology and morphology of both species and
a putative hybrid to determine the extent of inter and intraspecific variation in phenotypic traits.
I did not find evidence of a contact zone or hybridisation occurring between N. tuberculatus
and N. stellatus; all geckos sampled in this study from Denniston and Stockton plateaux were
morphologically and genetically part of N. tuberculatus. My results show significant
intraspecific phenotypic variation between populations for each species. For example, body
colour patterns of some populations are more similar between species than within. However,
concordance between genetic markers and colour combinations of mouth and tongue
provided evidence of clear species differences, and traits to distinguish the species, despite
intraspecific variation of other traits. Finally, I recorded detailed habitat parameters for each
individual and documented variation in perch height, both within populations and between sex.
This information helps conservation practitioners to implement best practice techniques for
green gecko conservation management by determining ecotypes and habitat use, population
variance, which can prevent the further decline of both genetic variation and risk to species.
Specifically, this research aids the mitigation of negative impacts by mining operations and
development, such as is the current threat to the Denniston and Stockton plateaux.--Shortened abstract