Zealand Lizards Research Articles

The Okuru skink (Oligosoma carinacauda sp. nov) of South Westland, New Zealand—simply elusive or extinct?

A small brown, longitudinally striped skink from Okuru, South Westland, New Zealand is described as Oligosoma carinacauda sp. nov. It is distinguished from all congeners by the combination of three supraocular scales and a keeled tail. The species is known only from a single specimen, collected from sphagnum moss within supralittoral dune habitat at Mussel Point, Okuru in 2000. Follow-up targeted surveys undertaken since by expert herpetologists have failed to relocate the species to date. As it is known that many New Zealand lizard species face a perilously uncertain future due to anthropogenic-induced pressures such as habitat loss, predatory pests, and climate change, there are serious concerns for the survival of this species.

Concrete refuges and the influence of temperature on artificial refuge occupation by terrestrial lizards

ABSTRACT Artificial refuges are commonly used to sample small reptiles and to provide supplementary shelter. For refuges to be effective, they should be safe and acceptable to reptiles. Current designs used for New Zealand lizards are vulnerable to trampling and degradation, restricting where they can be used without risk to lizards. We tested the usage of a new trampling-resistant concrete refuge, containing an internal crevice and basking ledge, by terrestrial lizards on the Port Hills in Canterbury, South Island. Twice a month we inspected 40 refuges on 20 occasions over one year which resulted in 420 gecko and 39 skink encounters. Geckos consistently used refuges throughout the year while skinks were infrequently found. Internal refuge surface and ambient air temperature data suggests that both overnight and day-time temperatures in the refuges were favourable for year-round occupation by geckos at the study site. Due to the low number of skinks, their occupancy was not analysed. Our refuge design appears to be a robust and effective design, particularly for crevice-dwelling geckos in trampling-prone and rocky habitats. Additional research is needed to investigate gecko movements in refuges at more extreme temperatures, test our design on other reptile species and assess potential restoration benefits. Zoobank LSID urn:lsid:zoobank.org:pub:71482E37-D73D-4362-AAE8-4AA15BE33A7F.

Rapid gain and loss of predator recognition by an evolutionarily naïve lizard

ABSTRACTThe introduction of mammalian predators often results in loss of native biodiversity due to naiveté of native prey to novel predators. In New Zealand, an island system with virtually no native mammalian predators, introduced mammalian predators threaten a large proportion of the native fauna. A critical step in adapting to introduced predators is the ability to recognize and respond to a novel predation threat. Whether New Zealand's lizards can do this has received little attention. We compared the basking behaviour of native McCann's skinks (Oligosoma maccanni) when exposed to a live cat (Felis catus), cat body odour, a model raptor (representing a coevolved predator) or procedural controls. We inferred predator recognition from reductions in individual basking and higher selection for basking sites with greater refuge availability. We tested these behavioural responses for two skink populations: one from an area with high abundance of mammalian predators including feral cats and the other from a fenced conservation reserve where predators have been excluded for over 10 years (3–4 skink generations). Skinks from the high‐predator population reduced basking when exposed to cat and raptor cues, whereas skinks from the predator‐free population did not. These results suggest that within approximately 150 years of exposure to novel predators, McCann's skinks might be able to recognize the threat posed by invasive mammals. However, they also demonstrate that predator recognition and antipredator behaviours may not necessarily be retained once gained. The rapid loss of basking‐related antipredator behaviours might reflect the high fitness costs of reduced basking for this species. Our results indicate that the behavioural response of skinks is flexible and that skinks may maximize individual fitness by balancing the risk of predation with the costs of antipredator behaviours.

Variable vulnerability to climate change in New Zealand lizards

AbstractAimThe primary drivers of species and population extirpations have been habitat loss, overexploitation and invasive species, but human‐mediated climate change is expected to be a major driver in future. To minimise biodiversity loss, conservation managers should identify species vulnerable to climate change and prioritise their protection. Here, we estimate climatic suitability for two species‐rich taxonomic groups, then use phylogenetic analyses to assess vulnerability to climate change.LocationAotearoa New Zealand (NZ).TaxaNZ lizards: diplodactylid geckos and eugongylinae skinks.MethodsWe built correlative species distribution models (SDMs) for NZ geckos and skinks to estimate climatic suitability under current climate and 2070 future climate scenarios. We then used Bayesian phylogenetic mixed models (BPMMs) to assess vulnerability for both groups with predictor variables for life‐history traits (body size and activity phase) and current distribution (elevation and latitude). We explored two scenarios: an unlimited dispersal scenario, where projections track climate, and a no‐dispersal scenario, where projections are restricted to areas currently identified as suitable.ResultsSDMs projected vulnerability to climate change for most modelled lizards. For species' ranges projected to decline in climatically suitable areas, average decreases were between 42% and 46% for geckos and 33% and 52% for skinks, although area did increase or remain stable for a minority of species. For the no‐dispersal scenario, the average decrease for geckos was 37%–52% and for skinks was 33%–52%. Our BPMMs showed phylogenetic signal in climate change vulnerability for both groups, with elevation increasing vulnerability for geckos, and body size reducing vulnerability for skinks.Main conclusionsNew Zealand lizards showed variable vulnerability to climate change, with most species' ranges predicted to decrease. For species whose suitable climatic space is projected to disappear from within their current range, managed relocation could be considered to establish populations in regions that will be suitable under future climates.

Does evolution in isolation from mammalian predators have behavioural and chemosensory consequences for New Zealand lizards?

Does evolution in isolation from mammalian predators have behavioural and chemosensory consequences for New Zealand lizards?

Lizards in the suburbs: a single-garden study of a small endemic New Zealand skink (Oligosoma aeneum)

ABSTRACTDetailed investigations of ecology and life history of lizards in New Zealand/Aotearoa are needed to inform their conservation and management. An early demographic study of copper skinks (Oligosoma aeneum) in a suburban garden was undertaken in Lower Hutt using mark–recapture methods, sampling weekly from March 1971 to December 1973. Oligosoma aeneum were seen on 1372 occasions, with 972 captures of 169 individuals. The maximum snout–vent length was 66 mm, 33% of skinks had complete tails, and colour differences suggested sexual signalling and warrant further study. Most captures occurred over November–March, with fewest over June–August. The estimated spring/summer population size in the garden (± SEM) was 83.6 (± 9.4) skinks, and the annual survival rate (± SEM) was 38.0% (± 16.0%). This is one of the few New Zealand lizard studies that have extended through all months of the year and it adds to limited information on lizard populations in suburban areas.

Unveiling the lizards of New Zealand

1 Unveiling the lizards of New Zealand 2 New Zealand Lizards, edited by David G. Chapple, 2016, Springer International Publishing, 3 375 pp. £100.50 (Hardcover) ISBN 978-3-319-41672-4 / £80.00 (eBook) ISBN 978-3-319- 4 41674-8; http://www.springer.com 5 In this comprehensive and authoritative volume, David Chapple and co-authors have 6 compiled a fascinating overview of the New Zealand lizards. Covering an impressive 7 spectrum of topics, the book details aspects ranging from the discovery, taxonomy and 8 evolutionary history of this lizard assemblage, to their ecology, conservation and focal areas 9 for future research. As described in the initial chapter, the principal aim of the book was to 10 synthesise current knowledge of the region’s lizard biota, and, in so doing, highlight crucial 11 knowledge gaps and key areas for future research. In this regard, I believe the book excels 12 and will provide a notable point of reference for both current and future reptile researchers. New Zealand lizards have long been underappreciated, both within the country and 14 abroad, and overshadowed by interest in the tuatara (Sphenodon punctatus). While just 15 under half of the proposed lizard species remain undescribed (45%; Chapple, chapter 1), the 16 diversity appears to be particularly remarkable considering New Zealand’s temperate setting. 17 A proliferation of research on the region’s lizard assemblage has enabled advances in 18 biogeographical analyses and conservation priority assessments. While this research and 19 expert knowledge form the backbone of the text, it is the author’s critical assessments of the 20 current research focus and recommendations for future directions that elevate this book 21 above others in its class. 22 Following the chronology of New Zealand herpetological discoveries, the opening chapters 23 detail the historical events and characters involved in unveiling the extant and extinct New

The diversity and evolution of nematodes (Pharyngodonidae) infecting New Zealand lizards.

Host-parasite co-evolutionary studies can shed light on diversity and the processes that shape it. Molecular methods have proven to be an indispensable tool in this task, often uncovering unseen diversity. This study used two nuclear markers (18S rRNA and 28S rRNA) and one mitochondrial (cytochrome oxidase subunit I) marker to investigate the diversity of nematodes of the family Pharyngodonidae parasitizing New Zealand (NZ) lizards (lygosomine skinks and diplodactylid geckos) and to explore their co-evolutionary history. A Bayesian approach was used to infer phylogenetic relationships of the parasitic nematodes. Analyses revealed that nematodes parasitizing skinks, currently classified as Skrjabinodon, are more closely related to Spauligodon than to Skrjabinodon infecting NZ geckos. Genetic analyses also uncovered previously undetected diversity within NZ gecko nematodes and provided evidence for several provisionally cryptic species. We also examined the level of host-parasite phylogenetic congruence using a global-fit approach. Significant congruence was detected between gecko-Skrjabinodon phylogenies, but our results indicated that strict co-speciation is not the main co-evolutionary process shaping the associations between NZ skinks and geckos and their parasitic nematodes. However, further sampling is required to fully resolve co-phylogenetic patterns of diversification in this host-parasite system.

A review of the parasitic mites of New Zealand skinks and geckos with new host records

ABSTRACTDespite a general awareness of mites parasitic on New Zealand native lizards, they have received little attention. In total, eight species have been described to infect New Zealand lizards; however, many of the records are decades old and are opportunistic encounters rather than focused surveys. This article reviews existing knowledge of these mites with particular focus given to identifying known distributional ranges and host species parasitised. To complement the literature review, a modest survey of the mite fauna of New Zealand lizards was conducted. Mites were collected from 10 lizard species from five different locations. Four mite species (Neotrombicula naultini, Ne. sphenodonti, Microtrombicula hoplodactyla and Odontacarus lygosomae) were recovered and identified. The study expands the known ranges of Ne. naultini, M. hoplodactyla and Odontacarus mites and provides a new host record for M. hoplodactyla. Importantly, this study highlights that our documentation of these mites is limited and incomplete.

Tony Whitaker: life and achievements of a pioneer New Zealand lizard ecologist

ABSTRACTTony Whitaker grew up in Pinehaven, north of Wellington, New Zealand. He soon became interested in natural history, with interests centred on lizard ecology. Newly developed nocturnal, mark–recapture and quadrat survey techniques enabled density and niche segregation studies, resulting in numerous scientific publications throughout his life. From 1966 to 1977 he worked as an ecologist at the Department of Scientific and Industrial Research (DSIR). His surveys of islands off northern New Zealand led to an important study of the impact of kiore (Polynesian rat; Rattus exulans) on lizard populations, showing that rat eradication was necessary for conservation. At DSIR he also researched birds and mammals. Later, Tony and his wife Viv established a farm near Motueka and began mainland studies of lizards, contracted to mining companies or the New Zealand Wildlife Service/Department of Conservation. Having built up a well-documented collection of New Zealand lizards (now at the Museum of New Zealand Te Papa Tongarewa), Tony then contributed to a bibliography, atlas and field guide. During the period when the taxonomy of lizards was revolutionised by the use of molecular techniques, Tony provided specimens, guidance and encouragement to many herpetologists. From 2000, his interests turned to the little-known and threatened lizards of New Caledonia, on which he contributed to 13 major papers. His life and work are here described under thematic, rather than strictly chronological, headings.

Step on it: can footprints from tracking tunnels be used to identify lizard species?

There are few effective or efficient established methods for monitoring cryptic herpetofauna. Footprint tracking tunnels are routinely used to index small mammal populations, but also have potential for monitoring herpetofauna. We evaluated the utility of tracking tunnels for identification of New Zealand lizards using captive- and wild-sourced animals (four skink and eight gecko species). All skink prints that we obtained were indistinct or obscure, but we obtained relatively clear, measurable prints for all gecko species. We found that identification to species level was possible for the two gecko species for which we had a large sample—Naultinus gemmeus and Woodworthia ‘Otago large’—using linear discriminant analysis (the best model correctly assigned 96.1% of individuals). Our findings suggest that footprints from tracking tunnels may be used to distinguish between species of geckos. Additional research is needed to assess the ability to further discriminate intra- and inter-genera lizard footprints from tracking tunnels, and the utility of the technique for surveying and monitoring lizard populations.

Functional connectivity and matrix quality: network analysis for a critically endangered New Zealand lizard

Agricultural modification commonly leads to reductions in vegetation matrix quality and a resultant decrease in functional connectivity. In this study, a network analysis approach was used to assess the impact of agriculturally-induced reductions in vegetation matrix quality on the metapopulation dynamics of the critically endangered New Zealand grand skink (Oligosoma grande). Vegetation matrix quality was quantified in four sites exhibiting differing levels of modification within indigenous tussock grasslands in eastern Central Otago, New Zealand. Grand skink occupancy probability exhibited a positive correlation with the structural connectivity of primary habitat within the more modified study sites, whereas in the least modified site a complex matrix appeared to compensate for low structural connectivity. Results from this research indicate that the matrix is an important determinant of grand skink metapopulation dynamics and that an intricate balance exists between structural connectivity and the quality of the vegetation matrix. This research highlights the importance of assessing the impact of the matrix for individual species, particularly for conservation management.

Detection of Salmonella during the translocation of two endemic New Zealand lizard species within the Hauraki Gulf

Multiple species translocations to the same site are becoming common practice in New Zealand restoration programmes. With every new translocation, the risk of parasite transmission between populations can increase. The translocation of Hoplodactylus duvaucelii and Oligosoma smithi provided the opportunity to 1) test for Salmonella and Cryptosporidium occurrences; and 2) compare this Salmonella test prevalence with results from avian translocations at one release site, Tiritiri Matangi Island. Of the six reptile species tested, three skinks (O. aeneum, O. moco and O. smithi) and one gecko (Woodworthia maculatus) tested positive for Salmonella (n=274). This is the first record of Salmonella enterica subspecies IV 40:g,t:- in New Zealand reptiles. Test prevalences between reptiles and birds were similar, suggesting that Salmonella prevalence may be naturally low in the areas sampled.

Life-history traits and extrinsic threats determine extinction risk in New Zealand lizards

A species’ vulnerability to extinction depends on extrinsic threats such as habitat loss, as well as its intrinsic ability to respond or adapt to such threats. Here we investigate the relative roles of extrinsic threats and intrinsic biological traits in determining extinction risk in the lizard fauna of New Zealand. Consistent with the results of previous studies on mammals and birds, we find that habitat specialization, body size and geographic range size are the strongest predictors of extinction risk. However, our analyses also reveal that lizards that occupy areas with high levels of annual rainfall and are exposed to exotic predators and high human population densities are at greater risk. Thus, while the intrinsic traits that render species prone to extinction appear largely congruent across vertebrate taxa, our findings illustrate that both extrinsic threats and intrinsic traits need to be considered in order to accurately predict, and hence prevent, future population declines.

Habitat use by southern forest geckos (Mokopirirakau ‘Southern Forest’) in the Catlins, Southland

Basic biological information is critical to evaluating conservation requirements for native taxa, but is lacking for many cryptic New Zealand lizard species. Southern forest geckos (Mokopirirakau ‘Southern Forest’) are known only from anecdotes, museum specimens and discoveries of an individual at each of three sites during recent surveys in the Catlins. We used systematic searching, photo identification and radio telemetry at one of these sites (Tahakopa Valley) to investigate habitat use of southern forest geckos. Forty-five hours of searching in 2010–2011 yielded 28 sightings of 17 individuals including four juveniles (indicating that a breeding population exists). Most geckos were found by searching a boulder used as a diurnal retreat site or in mānuka (Leptospermum scoparium). Two geckos were radio-tracked; both remained within 5 m of capture and exhibited primarily nocturnal behaviour. We recommend further survey work to identify populations and monitoring to evaluate the need for conservation intervention.

Frequency of tail loss does not reflect innate predisposition in temperate New Zealand lizards

Caudal autotomy (tail shedding) is a defence mechanism against predation which is used by lizards when other tactics, such as crypsis and escape, prove ineffective. The speed at which autotomy occurs has important implications for survival, and the accuracy of tail loss is of consequence for an individual's future fitness. Autotomy is shaped by both taxon-specific tail morphology as well as environmental factors such as predator history, and it can be difficult to distinguish between these processes. In this study, the frequency of tail-regeneration observed (field rate of autotomy), latency (speed of autotomy in the laboratory) and accuracy of tail loss were measured in six lizard species from two families (Scincidae and Diplodactylidae). The field rate and latency of autotomy was similar among all species except for the large nocturnal skink Oligosoma macgregori, which was less likely to autotomise. Latency and field rates of autotomy were not correlated, implying that the field rates of autotomy are related to predation attacks, social interactions, or some other environmental factor, rather than an innate disposition to autotomy. Further study, for example comparing populations with low and high predation pressure, will help to explain which of these factors are influencing autotomy rates.

Miocene skinks and geckos reveal long-term conservatism of New Zealand's lizard fauna

The New Zealand (NZ) lizard fossil record is currently limited to late Quaternary remains of modern taxa. The St Bathans Fauna (early Miocene, southern South Island) extends this record to 19-16 million years ago (Myr ago). Skull and postcranial elements are similar to extant Oligosoma (Lygosominae) skinks and Hoplodactylus (Diplodactylinae) geckos. There is no evidence of other squamate groups. These fossils, along with coeval sphenodontines, demonstrate a long conservative history for the NZ lepidosaurian fauna, provide new molecular clock calibrations and contradict inferences of a very recent (less than 8 Myr ago) arrival of skinks in NZ.

Daily Patterns of Metabolic Rate among New Zealand Lizards (Reptilia: Lacertilia: Diplodactylidae and Scincidae)

In addition to the effects of temperature fluctuations on metabolic rate, entrained endogenous rhythms in metabolism, which are independent of temperature fluctuations, may be important in overall energy metabolism in ectotherms. Daily entrained endogenous rhythms may serve as energy-conserving mechanisms during an animal's active or inactive phase. However, because nocturnal lizards often take advantage of thermal opportunities during the photophase (light), their daily metabolic rhythms may be less pronounced than those of diurnal species. We measured the rate of oxygen consumption (VO(2)) as an index of metabolic rate of eight temperate lizard species (four nocturnal, three diurnal, and one crepuscular/diurnal; n = 7-14) over 24 h at 13 degrees C and in constant darkness to test whether daily patterns (including amplitude, magnitude, and time of peak VO(2)) of metabolic rate in lizards differ with activity period. We also tested for phylogenetic differences in metabolic rate between skinks and geckos. Three daily patterns were evident: 24-h cycle, 12-h cycle, or no daily cycle. The skink Cyclodina aenea has a 12-h crepuscular pattern of oxygen consumption. In four other species, VO(2) increased with, or in anticipation of, the active part of the day, but three species had rhythms offset from their active phase. Although not correlated with activity period or phylogeny, amplitude of VO(2) may be correlated with whether a species is temperate or tropical. In conclusion, the metabolic rate of many species does not always correlate with the recorded activity period. The dichotomy of ecology and physiology may be clarified by more in-depth studies of species behaviors and activity periods.

Estimating site occupancy and detectability of an endangered New Zealand lizard, the Otago skink (Oligosoma otagense)

There is a need to develop appropriate monitoring methods for cryptic reptile species, such as the endangered New Zealand endemic Otago skink (Oligosoma otagense), that take into account incomplete detectability. A recently developed analytical technique was applied to presence–absence data for Otago skinks to derive robust estimates of both detection probability and site occupancy. The estimated detection probability for Otago skinks was 0.4 (s.e. 0.052), and the estimate of the proportion of the study area occupied by Otago skinks was 0.71 (s.e. 0.11). The data derived from presence–absence surveys in consistently sunny weather, with a standardised scanning and searching technique, provided a good basis for robust estimates of detection probability and of the percentage of area occupied by skinks. This survey technique could be applied to other similarly cryptic reptile species to derive rigorous estimates of site occupancy in order to track changes over time or in response to management interventions. It will be particularly appropriate where precise estimation of absolute abundance is not warranted, or where a simple index of relative abundance may be invalid due to failure of the implicit assumption of constant detectability.

Inferring Vulnerability to Introduced Predators without Experimental Demonstration: Case Study of Suter's Skink in New Zealand

Abstract: The coast‐inhabiting Suter's skink ( Oligosoma suteri ) has a fragmented distribution on islands around northern New Zealand, which has been attributed to the effects of introduced predators. We used classification trees to assess a range of factors that might influence the distribution of Suter's skinks. We then assessed the vulnerability to predation of juvenile and adult Suter's skinks by using a population viability analysis ( PVA ) model. We tested predictions from the classification tree and PVA models on two islands from which introduced Pacific rats ( Rattus exulans ) were removed. On one island, Suter's skinks were reintroduced ( assuming previous extirpation by rats ), and on the other the skinks had survived in the presence of Pacific rats. Our results revealed that populations of Suter's skinks are likely to be susceptible to predation where there are no bouldery beaches as refuges. Where these beaches are present, they are likely to function as refuges only if there is effective protection for adults. We conclude, however, that despite some apparently compelling circumstantial evidence of the effects of introduced predators on New Zealand lizards, it appears impractical to verify cause and effect with field manipulations if lizards and introduced predators do not already coexist.