Blood parasites in sympatric lizards: what is their impact on hosts’ immune system?

Assessment of parasites and their pathogenicity is essential for studying the ecology of populations and understanding their dynamics. In this study, we investigate the prevalence and intensity of infection of haemogregarines (phylum Apicomplexa) in two sympatric lizard species, Podarcis vaucheri and Scelarcis perspicillata, across three localities in Morocco, and their effect on host immune response. We used the Phytohaemagglutinin (PHA) skin testing technique to relate the level of immune response with parasite infection. Prevalence and intensity levels were estimated with microscopy, and 18S rRNA gene sequences were used to confirm parasite identity. All parasites belong to the haemogregarine lineage found in other North African reptiles. There were differences in prevalence between localities and sexes. Overall, infected lizards were larger than uninfected ones, although we did not detect differences in parasitaemia across species, sex or locality. The swelling response was not related to the presence or number of haemogregarines, or to host body size, body condition, sex or species. We found no evidence of impact for these parasites on the circulating blood cells or the hosts’ immune system, but more data is needed to assess the potential impact of mixed infections, and the possibility of cryptic parasite species.

Acanthosaura meridiona sp. nov. (Squamata: Agamidae), a new short-horned lizard from southern Thailand

A new short – horned lizard species of the genus Acanthosaura from southern Thailand, is described herein. The species was previously recognised as Acanthosaura crucigera and has been reported to present a wide distribution across mainland south-east Asia. The combination of modern morphological studies of Acanthosaura meridiona sp. nov. allows its separation from closely related species A. crucigera, on the basis of presenting more nuchal scales, more scales between diastema, more scales bordering rostral scales and more midline ventral scales. Mitochondrial DNA analysis also indicated a sister relationship between A. meridiona sp. nov. and A. crucigera with a 100 % probability according to Bayesian and maximum – likelihood analyses. The pairwise distance between A. meridiona sp. nov. and A. crucigera ranges from 9.9 – 11.1 %, while the distance between A. meridiona populations ranges from 0 – 0.9 %. This new discovery contributes to the redescription of the distribution of A. crucigera under Kra Isthmus and its replacement by A. meridiona sp. nov.

The correct name for the North African rock lizard is Agama bibronii A. Duméril in Duméril & Duméril, 1851, not Agama impalearis Boettger, 1874 (Reptilia, Squamata)

Over half a century ago, Mertens (1955) noted that the name Agama bibronii A. Duméril in Duméril & Duméril, 1851 for a North African agamid lizard species was preoccupied by Trapelus (Psammorrhoa) bibronii Fitzinger, 1843, a species inhabiting South Africa. He consequently stated that the next available name for Agama bibronii ‘Duméril, 1851’, namely Agama colonorum var. impalearis Boettger, 1874 should be applied to this taxon. Until today, the herpetological literature contains examples where either Agama bibronii ‘Duméril, 1851’ or Agama impalearis Boettger, 1874 is used to denominate the North African rock agama. However, an apparently overlooked ruling by the Commission suppressed the name Trapelus (Psammorrhoa) bibronii Fitzinger, 1843, so that Agama bibronii A. Duméril in Duméril & Duméril, 1851 is the valid name for the North African rock agama.

ERYTHROLAMPRUS MILIARIS (LINNAEUS, 1758) (SQUAMATA: DIPSADIDAE) A NEW PREY ITEM OF TROPIDURUS TORQUATUS (WIED-NEUWIED, 1820) (SQUAMATA: TROPIDURIDAE) IN SOUTHEASTERN BRAZIL

Although ophiophagy is not a well-known event among neotropical lizards, occasional snake predation events have been reported for some species. For Tropidurus torquatus only one record of predation on Phalotris matogrossensis is currently known. Here we report the second record of ophiophagy in Tropidurus torquatus, adding a new prey item to its known diet, and we provide a review of vertebrate prey consumed by this enigmatic lizard species. Although when compared to other lizard species, T. torquatus has a substantial number of records documenting the predation of small vertebrates, these records are occasional and are likely the result of opportunistic events.

Evaluating Environmental Enrichment Methods in Three Zoo-Housed Varanidae Lizard Species

Environmental enrichment has been shown to enhance the behavioural repertoire and reduce the occurrence of abnormal behaviours, particularly in zoo-housed mammals. However, evidence of its effectiveness in reptiles is lacking. Previously, it was believed that reptiles lacked the cognitive sophistication to benefit from enrichment provision, but studies have demonstrated instances of improved longevity, physical condition and problem-solving behaviour as a result of enhancing husbandry routines. In this study, we evaluate the effectiveness of food- and scent-based enrichment for three varanid species (Komodo dragon, emerald tree monitor lizard and crocodile monitor). Scent piles, scent trails and hanging feeders resulted in a significant increase in exploratory behaviour, with engagement diminishing ≤330 min post provision. The provision of food- versus scent-based enrichment did not result in differences in enrichment engagement across the three species, suggesting that scent is just as effective in increasing natural behaviours. Enhancing the environment in which zoo animals reside is important for their health and wellbeing and also provides visitors with the opportunity to observe naturalistic behaviours. For little known and understudied species such as varanids, evidence of successful (and even unsuccessful) husbandry and management practice is vital for advancing best practice in the zoo industry.

Territorial Displays of the Ctenophorus decresii Complex: A Story of Local Adaptations

Closely related species make for interesting model systems to study the evolution of signaling behavior because they share evolutionary history but have also diverged to the point of reproductive isolation. This means that while they may have some behavioral traits in common, courtesy of a common ancestor, they are also likely to show local adaptations. The Ctenophorus decresii complex is such a system, and comprises six closely related agamid lizard species from Australia: C. decresii, C. fionni, C. mirrityana, C. modestus, C. tjanjalka, and C. vadnappa. In this study, we analyze the motion displays of five members of the C. decresii complex in the context of their respective habitats by comparing signal structure, habitat characteristics and signal contrast between all species. Motor pattern use and the temporal sequence of motor patterns did not differ greatly, but the motion speed distributions generated during the displays were different for all species. There was also variation in the extent to which signals contrasted with plant motion, with C. vadnappa performing better than the other species at all habitats. Overall, this study provides evidence that members of the C. decresii complex exhibit local adaptations in signaling behavior to their respective habitat, but they also maintain some morphological and behavioral traits in common, which is likely a consequence from the ancestral state.

Assessing bird predation on New Zealand’s lizard fauna using lizard-mimicking replicas

<p>Wildlife management is fraught with challenges due to the complexities of community ecology. Interventions aimed at restoring ecosystems, or managing species, can have unintended negative outcomes for target species. The effect of avian predation on native lizard fauna in New Zealand is not clearly understood, despite birds being regarded as top predators within mammal-free ecosystems. At least thirty-one species of bird have been recorded preying on native lizards, but few studies have directly addressed avian predation on lizards, with the majority of evidence sourced from published anecdotes. New Zealand’s herpetofauna are already vulnerable due to range contractions resulting from mammalian predation and habitat loss, with 87% of New Zealand lizard species considered ‘At Risk’ or ‘Threatened’. Understanding the risks posed to lizards will help to inform successful management of vulnerable populations. I used lizard-mimicking replicas to identify and assess predation rates exerted by bird species on lizard populations within the Wellington region of New Zealand. I examined the use of lizard replicas as a tool to quantify predation by examining how birds interacted with replicas and comparing attack rates with novel items simultaneously placed in the field. I determined which bird species were preying on replicas, the extent of such predation, and whether site vegetation or daily weather influenced the probability of avian attack on replicas. Although attack frequency did not differ between novel items and lizard replicas, birds exhibited a realistic predatory response by preferentially attacking the head of lizard replicas. Interactions by birds with lizard-mimicking replicas cannot be confirmed as true predation attempts, but lizard replicas can nevertheless be used to quantify predation pressures exerted on lizard populations by opportunistic bird species. Seven ground-foraging bird species were found to attack lizard replicas. Two species, the pūkeko (Porphyrio melanotus melanotus) and southern black-backed gull (Larus dominicanus dominicanus), were identified as high impact species. The average predation risk experienced by lizard replicas varied greatly across environments, with 0 – 25% of replicas attacked daily at sites. Canopy cover and daily rainfall were not significant predictors, but potentially decreased the likelihood of replica attack. Predation risk varied for lizard replicas as a result of differing assemblages of bird predators at sites, and the presence and foraging behaviour of specific predatory birds. Predation by birds is likely to be an issue where predation pressure is high, or lizard populations are small, range restricted, or recovering from the presence of mammalian predators. When managing vulnerable lizard populations, managers should take into account the threats posed by avian predators so that lizard communities can recover successfully following the same trajectory as native birds.</p>

Is habitat enhancement a viable strategy for conserving New Zealand's endemic lizards?

<p>In our current era, the Anthropocene, species are disappearing at an unprecedented rate due to the impact of humans on Earth’s environments. Of the many causes of these extinctions, habitat loss is thought to be the most severe. Three habitat management strategies are available for halting habitat loss: reservation, restoration and reconciliation. The latter two of these strategies actively seek to improve the ability of degraded or lost habitats to support species. If successful on a large enough scale, use of restoration and reconciliation (hereafter referred to collectively as ‘habitat enhancement’) could reverse the effects of habitat loss. I evaluated the viability of habitat enhancement for the conservation of New Zealand’s lizard fauna. 83% of New Zealand’s 106+ endemic species are threatened or at risk of extinction. While habitat loss is one key driver of declines, predation by invasive mammals is the other. Neither of these processes are well understood. Habitat enhancement is increasingly being employed in New Zealand by landowners, community groups, conservationists, and businesses as a strategy for mitigating lizard declines, but outcomes are rarely investigated comprehensively. This is concerning because habitat manipulation potentially affects both exotic and native species, which has led to unexpected negative effects on threatened fauna in New Zealand and overseas. I posed four questions to help address this knowledge gap. (1) What habitat enhancement strategies are available for reptiles, and have they produced successful conservation outcomes? (2) How do habitat characteristics affect populations and communities of endemic New Zealand lizards? (3) How does the presence of invasive mammals affect populations and communities of endemic New Zealand lizards over intermediate to long-term time frames? (4) Can habitat enhancement produce positive conservation outcomes in the presence of invasive mammals? A review of the global literature on habitat enhancement for reptiles identified 75 studies documenting 577 responses of 251 reptile species. For outcome evaluation, I adapted an existing stage-based framework for assessment of translocation success. High levels of success (84-85%) at Stages 1 (use of enhanced habitat) and 2 (evidence of reproduction in enhanced habitat) suggested that enhancement could be useful for creating areas that can be inhabited, and reproduced in, by reptiles. Fewer cases were successful at Stage 3 (30%; improvement of at least one demographic parameter demonstrated in enhanced habitat) or Stage 4 (43%; self-sustaining or source population established in enhanced habitat). Additionally, only 1% of the 577 cases sufficiently examined or modelled long-term population trends to allow evaluation against the Stage 4 criterion. Thus, there was a lack of evidence indicating that enhancement could result in higher population growth rates, or reduced extinction risk, of reptiles. I conducted field work in the Wellington region to investigate the effects of habitat characteristics and mammals on terrestrial lizards inhabiting coastal environments. Surveys conducted in two mammal-invaded mainland areas and on two mammal-free offshore islands showed that presence or absence of invasive mammals had a stronger effect on lizard community structure than habitat variables. However, occupancy probabilities of northern grass skinks Oligosoma polychroma and Raukawa geckos Woodworthia maculata were positively correlated with increasing cover of divaricating shrubs. O. polychroma were also more likely to occupy patches with increasing cover by non-Muehlenbeckia vines. Mark-recapture studies were conducted at two mammal-invaded mainland sites to investigate the current abundance of lizard species: Turakirae Head and Pukerua Bay. Estimated densities of O. polychroma ranged between 3,980 and 4,078 individuals / ha and W. maculata between 4,067 and 38,372 individuals / ha. Other species known to occur, at least historically, at each site were either not detected or comprised only a small proportion of total lizard captures. Analysis of longitudinal lizard monitoring data available for Pukerua Bay, Turakirae Head, and an additional mammal-invaded site, Baring Head, did not reveal a significant decline in abundance, occupancy, or catch rates of O. polychroma over time periods ranging between six and 34 years, nor of W. maculata over six to 49 years. Habitat information available for Baring Head showed that the probability of local extinction of W. maculata was significantly lower at rocky sites. Finally, I conducted a before-after-control-impact habitat enhancement experiment on lizard communities inhabiting 100 m2 plots on the mammal-invaded Miramar Peninsula. After a six-month pre-enhancement monitoring period, native plants and gravel piles were added to enhancement plots and lizard monitoring continued for a further nine months. Enhancement did not significantly affect plot use, body condition, or evidence of reproduction in Oligosoma aeneum, O. polychroma or W. maculata, but were considered successful at Stages 1 and 2 due to the absence of a negative effect. Neither the abundance, probability of entry into plots by birth or immigration, nor apparent survival of O. aeneum was significantly affected by enhancement (Stage 3). Apparent survival of O. polychroma increased significantly in response to enhancement, but this did not result in increased abundance. Adding gravel and native vegetation (especially divaricating shrubs and vines) may be a suitable strategy for creating habitat in invaded coastal landscapes for O. polychroma and W. maculata. However, most of the other lizard species that would have historically occurred in mammal-invaded coastal areas of Wellington appeared to be sensitive to sustained mammal presence, even with low-to-moderate levels of control in operation. Therefore, habitat enhancement without intensive mammal control or eradication is not expected to benefit these species, nor be capable of restoring coastal lizard communities. In invaded landscapes it is, at best, a reconciliation measure that could allow co-existence of an endemic lizard community comprised of common species with invasive mammals. However, habitat enhancement could still be useful for restoring lizard communities in mammal-free sanctuaries.</p>

Is habitat enhancement a viable strategy for conserving New Zealand's endemic lizards?

<p>In our current era, the Anthropocene, species are disappearing at an unprecedented rate due to the impact of humans on Earth’s environments. Of the many causes of these extinctions, habitat loss is thought to be the most severe. Three habitat management strategies are available for halting habitat loss: reservation, restoration and reconciliation. The latter two of these strategies actively seek to improve the ability of degraded or lost habitats to support species. If successful on a large enough scale, use of restoration and reconciliation (hereafter referred to collectively as ‘habitat enhancement’) could reverse the effects of habitat loss. I evaluated the viability of habitat enhancement for the conservation of New Zealand’s lizard fauna. 83% of New Zealand’s 106+ endemic species are threatened or at risk of extinction. While habitat loss is one key driver of declines, predation by invasive mammals is the other. Neither of these processes are well understood. Habitat enhancement is increasingly being employed in New Zealand by landowners, community groups, conservationists, and businesses as a strategy for mitigating lizard declines, but outcomes are rarely investigated comprehensively. This is concerning because habitat manipulation potentially affects both exotic and native species, which has led to unexpected negative effects on threatened fauna in New Zealand and overseas. I posed four questions to help address this knowledge gap. (1) What habitat enhancement strategies are available for reptiles, and have they produced successful conservation outcomes? (2) How do habitat characteristics affect populations and communities of endemic New Zealand lizards? (3) How does the presence of invasive mammals affect populations and communities of endemic New Zealand lizards over intermediate to long-term time frames? (4) Can habitat enhancement produce positive conservation outcomes in the presence of invasive mammals? A review of the global literature on habitat enhancement for reptiles identified 75 studies documenting 577 responses of 251 reptile species. For outcome evaluation, I adapted an existing stage-based framework for assessment of translocation success. High levels of success (84-85%) at Stages 1 (use of enhanced habitat) and 2 (evidence of reproduction in enhanced habitat) suggested that enhancement could be useful for creating areas that can be inhabited, and reproduced in, by reptiles. Fewer cases were successful at Stage 3 (30%; improvement of at least one demographic parameter demonstrated in enhanced habitat) or Stage 4 (43%; self-sustaining or source population established in enhanced habitat). Additionally, only 1% of the 577 cases sufficiently examined or modelled long-term population trends to allow evaluation against the Stage 4 criterion. Thus, there was a lack of evidence indicating that enhancement could result in higher population growth rates, or reduced extinction risk, of reptiles. I conducted field work in the Wellington region to investigate the effects of habitat characteristics and mammals on terrestrial lizards inhabiting coastal environments. Surveys conducted in two mammal-invaded mainland areas and on two mammal-free offshore islands showed that presence or absence of invasive mammals had a stronger effect on lizard community structure than habitat variables. However, occupancy probabilities of northern grass skinks Oligosoma polychroma and Raukawa geckos Woodworthia maculata were positively correlated with increasing cover of divaricating shrubs. O. polychroma were also more likely to occupy patches with increasing cover by non-Muehlenbeckia vines. Mark-recapture studies were conducted at two mammal-invaded mainland sites to investigate the current abundance of lizard species: Turakirae Head and Pukerua Bay. Estimated densities of O. polychroma ranged between 3,980 and 4,078 individuals / ha and W. maculata between 4,067 and 38,372 individuals / ha. Other species known to occur, at least historically, at each site were either not detected or comprised only a small proportion of total lizard captures. Analysis of longitudinal lizard monitoring data available for Pukerua Bay, Turakirae Head, and an additional mammal-invaded site, Baring Head, did not reveal a significant decline in abundance, occupancy, or catch rates of O. polychroma over time periods ranging between six and 34 years, nor of W. maculata over six to 49 years. Habitat information available for Baring Head showed that the probability of local extinction of W. maculata was significantly lower at rocky sites. Finally, I conducted a before-after-control-impact habitat enhancement experiment on lizard communities inhabiting 100 m2 plots on the mammal-invaded Miramar Peninsula. After a six-month pre-enhancement monitoring period, native plants and gravel piles were added to enhancement plots and lizard monitoring continued for a further nine months. Enhancement did not significantly affect plot use, body condition, or evidence of reproduction in Oligosoma aeneum, O. polychroma or W. maculata, but were considered successful at Stages 1 and 2 due to the absence of a negative effect. Neither the abundance, probability of entry into plots by birth or immigration, nor apparent survival of O. aeneum was significantly affected by enhancement (Stage 3). Apparent survival of O. polychroma increased significantly in response to enhancement, but this did not result in increased abundance. Adding gravel and native vegetation (especially divaricating shrubs and vines) may be a suitable strategy for creating habitat in invaded coastal landscapes for O. polychroma and W. maculata. However, most of the other lizard species that would have historically occurred in mammal-invaded coastal areas of Wellington appeared to be sensitive to sustained mammal presence, even with low-to-moderate levels of control in operation. Therefore, habitat enhancement without intensive mammal control or eradication is not expected to benefit these species, nor be capable of restoring coastal lizard communities. In invaded landscapes it is, at best, a reconciliation measure that could allow co-existence of an endemic lizard community comprised of common species with invasive mammals. However, habitat enhancement could still be useful for restoring lizard communities in mammal-free sanctuaries.</p>

Assessing bird predation on New Zealand’s lizard fauna using lizard-mimicking replicas

<p>Wildlife management is fraught with challenges due to the complexities of community ecology. Interventions aimed at restoring ecosystems, or managing species, can have unintended negative outcomes for target species. The effect of avian predation on native lizard fauna in New Zealand is not clearly understood, despite birds being regarded as top predators within mammal-free ecosystems. At least thirty-one species of bird have been recorded preying on native lizards, but few studies have directly addressed avian predation on lizards, with the majority of evidence sourced from published anecdotes. New Zealand’s herpetofauna are already vulnerable due to range contractions resulting from mammalian predation and habitat loss, with 87% of New Zealand lizard species considered ‘At Risk’ or ‘Threatened’. Understanding the risks posed to lizards will help to inform successful management of vulnerable populations. I used lizard-mimicking replicas to identify and assess predation rates exerted by bird species on lizard populations within the Wellington region of New Zealand. I examined the use of lizard replicas as a tool to quantify predation by examining how birds interacted with replicas and comparing attack rates with novel items simultaneously placed in the field. I determined which bird species were preying on replicas, the extent of such predation, and whether site vegetation or daily weather influenced the probability of avian attack on replicas. Although attack frequency did not differ between novel items and lizard replicas, birds exhibited a realistic predatory response by preferentially attacking the head of lizard replicas. Interactions by birds with lizard-mimicking replicas cannot be confirmed as true predation attempts, but lizard replicas can nevertheless be used to quantify predation pressures exerted on lizard populations by opportunistic bird species. Seven ground-foraging bird species were found to attack lizard replicas. Two species, the pūkeko (Porphyrio melanotus melanotus) and southern black-backed gull (Larus dominicanus dominicanus), were identified as high impact species. The average predation risk experienced by lizard replicas varied greatly across environments, with 0 – 25% of replicas attacked daily at sites. Canopy cover and daily rainfall were not significant predictors, but potentially decreased the likelihood of replica attack. Predation risk varied for lizard replicas as a result of differing assemblages of bird predators at sites, and the presence and foraging behaviour of specific predatory birds. Predation by birds is likely to be an issue where predation pressure is high, or lizard populations are small, range restricted, or recovering from the presence of mammalian predators. When managing vulnerable lizard populations, managers should take into account the threats posed by avian predators so that lizard communities can recover successfully following the same trajectory as native birds.</p>