Herbert S.M.,University of Otago |
Herbert S.M.,EcoGecko Consultants Ltd. |
Leung T.L.F.,University of Otago |
Leung T.L.F.,University of New England of Australia |
Bishop P.J.,University of Otago
Diseases of Aquatic Organisms | Year: 2011
The dissemination of the virulent pathogen Batrachochytrium dendrobatidis (Bd) has contributed to the decline and extinction of many amphibian species worldwide. Several different strains have been identified, some of which are sympatric. Interactions between co-infecting strains of a pathogen can have significant influences on disease epidemiology and evolution; therefore the dynamics of multi-strain infections is an important area of research. We stained Bd cells with 2 fluorescent BODIPY® fatty acid probes to determine whether these can potentially be used to distinguish and track Bd cell lines in multi-strain experiments. Bd cells in broth culture were stained with 5 concentrations of green-fluorescent BODIPY FL and red-fluorescent BODIPY 558/568 and visualized under an epifluorescent microscope for up to 16 d post-dye. Dyed strains were also assessed for growth inhibition. The most effective concentration for both dyes was 10 μM. This concentration of dye produced strong fluorescence for 12 to 16 d in Bd cultures held at 23°C (3 to 4 generations), and did not inhibit Bd growth. Cells dyed with BODIPY FL and BODIPY 558/568 can be distinguished from each other on the basis of their fluorescence characteristics. Therefore, it is likely that this technique will be useful for research into multi-strain dynamics of Bd infections. © 2011 Inter-Research.
Knox C.D.,EcoGecko Consultants Ltd.
Animal Conservation | Year: 2014
Translocation is an essential conservation tool often used to re-establish reptile populations following anthropogenic extirpation, but is not always successful. One factor potentially limiting success is dispersal of individuals from the release site immediately after translocation and consequent non-overlap of ranges. 'Penning' involves the use of an enclosure to restrict dispersal of translocated animals for a pre-determined period of time, with the aim of habituating animals to the release site so that they will establish a breeding population. We evaluated the utility of penning for limiting post-translocation dispersal of jewelled geckos (Naultinus gemmeus) by simultaneously tracking 19 geckos that had either been translocated into a pen for 9-10 months prior to the pen's removal (n=10) or were translocated to a nearby site with no physical barrier to dispersal (n=9) over a 3-week period. The area occupied by penned geckos did not increase following removal of their pen, despite suitable habitat being available outside the pen area. In contrast, un-penned geckos moved distances of up to 40m outside of their release area, and effectively increased the area that they were occupying as a group 4.4-fold over the 3-week period. We suspect that when Naultinus geckos are released without time in a pen, some individuals may disperse too far to contribute to a breeding population and, consequently, the likelihood of population establishment and rate of population growth may be diminished. Our hypothesis is supported by a survey we conducted the following summer in which all four adult female geckos found at the penned site were gravid, but neither of the females resighted at the un-penned site was gravid. We believe that the potential advantages of penning (e.g. restricting initial dispersal, increased ease of monitoring) may outweigh the disadvantages (e.g. cost) for many herpetofauna translocations. © 2014 The Zoological Society of London.
Harvey D.S.,EcoGecko Consultants Ltd |
Harvey D.S.,University of Illinois at Urbana - Champaign |
Lentini A.M.,Toronto Zoo |
Cedar K.,Ojibway Nature Center |
Weatherhead P.J.,University of Illinois at Urbana - Champaign
Herpetological Conservation and Biology | Year: 2014
Relocating snakes is used to reduce potential snake-human conflict and to re-establish or augment populations. Relocation may be unsuccessful if snakes attempt to home back to their capture locations or otherwise alter their behavior in ways that reduce fitness. To better understand the conditions under which the technique is likely to be successful, we conducted two types of relocation (repatriation and short-distance translocation) using Eastern Massasaugas (Sistrurus c. catenatus) in Ontario. For the repatriation experiment, 27 snakes were captive-born, raised for four years, and released into a nature reserve previously known to host massasaugas. Other than being relatively sedentary, snakes behaved normally upon release in that they engaged in reproductive behavior. Survival (70%) was relatively high until hibernation (19 weeks). However, none of the snakes that did hibernate (n = 19) survived into the following active season. In a preliminary assessment of the effects of short-distance translocation, snakes that we moved 200 m from capture locations (n = 4) did not return, nor did they exhibit abnormal movement or basking behavior relative to non-translocated controls (n = 7). The different outcomes of our two relocations could indicate that the success of relocation depends on the extent of displacement and the source of relocated individuals, although corroborating evidence is needed before these results can be used to support management strategies. © 2013. Daniel Harvey. All Rights Reserved.
Ohmer M.E.,University of Otago |
Herbert S.M.,University of Otago |
Herbert S.M.,Tropical Health Solutions Pty Ltd |
Speare R.,James Cook University |
And 2 more authors.
Animal Conservation | Year: 2013
The spread of chytridiomycosis, an emerging infectious disease caused by the fungal pathogen Batrachochytrium dendrobatidis (Bd), is one of many threats facing amphibians worldwide. Ascertaining the severity of this threat to particular amphibian species is necessary if managers are to prioritize conservation actions. In New Zealand, Bd has been detected on both threatened endemic (Leiopelma spp.) and widespread introduced (Litoria spp.) anuran species, but Le. archeyi, one of four native species, has demonstrated low susceptibility to chytridiomycosis in captivity. To determine potential impacts of Bd on New Zealand's native anuran fauna, we assessed the susceptibility of two native species, Le. pakeka and Le. hochstetteri, to chytridiomycosis. We exposed Bd-naïve individuals to a virulent New Zealand isolate of Bd, and monitored infection status with quantitative real-time polymerase chain reaction. Both species demonstrated low susceptibility and all individuals cleared Bd infection (Le. hochstetteri by week 10, Le. pakeka by week 15). Furthermore, no frogs demonstrated clinical signs of chytridiomycosis. Since Le. archeyi has similarly demonstrated low susceptibility, this appears to be a genus-wide trend, which warrants further study of the mechanism of this response. These findings, in agreement with results from field surveys and analyses of skin peptide defenses, suggest that Bd poses a low risk to leiopelmatids. An investigative study of potential susceptibility to Bd, such as this one, can better equip managers to target imminent threats and focus conservation plans for at-risk amphibian fauna. © 2012 The Zoological Society of London.
PubMed | University of Otago and EcoGecko Consultants Ltd
Type: | Journal: Parasitology | Year: 2016
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.