Takahe Research Articles

A lower motor neuron disease in takahē (Porphyrio hochstetteri) is an endoplasmic reticulum storage disease

Aims: To investigate the pathogenesis of a disease in takahē with intracytoplasmic inclusion bodies in lower motor neurons. Methods: Four cases aged between 5 and 12 years, from three different wildlife sanctuaries in New Zealand were examined. Of these, only one had signs of spinal dysfunction in the form of paresis. Stained paraffin sections of tissues were examined by light microscopy and immunostained sections of the ventral horn of the spinal cord by confocal microscopy. Epoxy resin sections of the bird with spinal dysfunction were examined by electron microscopy. Results: Two types of inclusion bodies were noted, but only in motor neurons of the ventral spinal cord and brain stem. These were large globoid eosinophilic bodies up to 5 µm in diameter, and yellow/brown granular inclusions mostly at the pole of the cell. The globoid bodies stained with Luxol fast blue but not with periodic acid Schiff (PAS), or Sudan black. The granular inclusions stained with Luxol fast blue, PAS and Sudan black. Both bodies were slightly autofluorescent. On electron microscopy the globoid bodies had an even electron-dense texture and were bound by a membrane. Beneath the membrane were large numbers of small intraluminal vesicles. The smaller granular bodies were more heterogeneous, irregularly rounded and membrane-bound accumulations of granular electron-dense material, often with electron-lucent vacuoles. Others were more vesicular but contained varying amounts of electron-dense material. The large globoid bodies did not immunostain for lysosomal markers lysosomal associated protein 1 (LAMP1) or cathepsin D so they were not lysosomal. The small granular bodies stained for cathepsin D by a chromogenic method. A kindred matrix analysis showed two cases to be as closely related as first cousins, and another case was almost as closely related to one of them, but the fourth bird was unrelated to any other. Conclusions: It was concluded that this was an endoplasmic reticulum storage disease due to a specific protein misfolding within endoplasmic reticulum. It was rationalised that the two types of inclusions reflected the same aetiology, but that misfolded protein in the smaller granular bodies had entered the lysosomal system via endoplasmic reticulum autophagy. Although the cause was unclear, it most likely had a genetic aetiology or predisposition and, as such, has clinical relevance.

Gut microbiota of the threatened takah\u0113: biogeographic patterns and conservation implications

BackgroundThe Aotearoa New Zealand takahē (Porphyrio hochstetteri), once thought to be extinct, is a nationally threatened flightless rail under intensive conservation management. While there has been previous research into disease-related microbes in takahē, little is known about the microbes present in the gastrointestinal tract. Given the importance of gut-associated microbes to herbivore nutrition and immunity, knowledge of these communities is likely to be of considerable conservation value. Here we examined the gut microbiotas of 57 takahē at eight separate locations across Aotearoa New Zealand.ResultsFaecal samples, taken as a proxy for the hindgut bacterial community, were subjected to 16S rRNA gene amplicon sequencing using Illumina MiSeq. Phylogenetic analysis of > 2200 amplicon sequence variants (ASVs) revealed nine main bacterial phyla (Acidobacteriota, Actinobacteriota, Bacteroidota, Campilobacterota, Firmicutes, Fusobacteriota, Planctomycetota, Proteobacteria, and Verrucomicrobiota) that accounted for the majority of sequence reads. Location was a significant effect (p value < 0.001, 9999 permutations) that accounted for 32% of the observed microbiota variation. One ASV, classified as Lactobacillus aviarius, was present in all samples at an average relative abundance of 17% (SD = 23.20). There was strong evidence (p = 0.002) for a difference in the abundance of the genus Lactobacillus between locations. A common commensal bacterium previously described in takahē, Campylobacter spp., was also detected in most faecal samples.ConclusionsLocation plays a pivotal role in the observed variation among takahē gut bacterial communities and is potentially due to factors such as supplemental feeding and medical treatment experienced by birds housed in captivity at one of the eight sampled sites. These data present a first glimpse of the previously unexplored takahē gut microbiota and provide a baseline for future microbiological studies and conservation efforts.

Novel Conditions in Conservation Translocations: A Conservative-Extrapolative Strategic Framework

In response to anthropogenic threats, conservation translocations are increasingly used to combat species' population and range declines. However, moving animals outside of their current distribution can mean introducing them to novel conditions, even in the case of reintroductions to formerly inhabited areas due to ecosystem changes following extirpation. This exposure to novel conditions introduces uncertainty that can undermine decision making for species conservation. Here we propose two strategies, which we define as conservative and extrapolative, for approaching and managing novelty and the resulting uncertainty in conservation translocations. Conservative strategies are characterised by the avoidance and removal of novel conditions as much as possible, whereas extrapolative strategies are more experimental, allowing exposure to novel conditions and monitoring outcomes to increase understanding of a species' ecology. As each strategy carries specific risks and opportunities, they will be applicable in different scenarios. Extrapolative strategies suit species in recovery which can afford some experimental management, or species facing novel and emerging threats which require less traditional translocations, such as assisted colonisations. We provide examples, applying our framework to two endemic New Zealand species with long histories of translocation management: tuatara (Sphenodon punctatus), a reptile and takahē (Porphyrio hochstetteri), a flightless bird.

SEABIRDS AS POSSIBLE RESERVOIRS OF ERYSIPELOTHRIX RHUSIOPATHIAE ON ISLANDS USED FOR CONSERVATION TRANSLOCATIONS IN NEW ZEALAND.

Erysipelothrix rhusiopathiae, the causative agent of the disease erysipelas, is a gram-positive bacillus, and an opportunistic pathogen in diverse species of animals. In New Zealand, E. rhusiopathiae has killed endangered birds on offshore islands, including Kākāpō (Strigops habroptilus), Takahē (Porphyrio hochstetteri), and Kiwi (Apteryx spp.). The source of infection is uncertain, and the prevalence of E. rhusiopathiae among wild birds is currently unknown. During October 2018 to December 2018, we surveyed dead and live seabirds that visit two of New Zealand's offshore islands used for Kākāpō conservation with the goal of determining the prevalence of E. rhusiopathiae. Bone marrow from dead birds was cultivated on selective agar, and organisms cultured were identified using matrix-assisted laser desorption/ionization with time-of-flight mass spectrometry. The prevalence of E. rhusiopathiae was calculated in different species for each island. We surveyed live birds using PCR with Erysipelothrix spp.-specific primers on blood samples. The prevalence of E. rhusiopathiae in dead seabirds on Whenua Hou and Te Hauturu-o-Toi was 3.4% (3/86) and 11.4% (5/44), respectively. On Whenua Hou, E. rhusiopathiae was detected in Sooty Shearwaters (Puffinus griseus; 5.9%, 2/34) and Mottled Petrels (Pterodroma inexpectata; 2.7%, 1/36) while it was detected only in Cook's Petrels (Pterodroma cookie; 13.5%, 5/37) on Te Hauturu-o-Toi. Blood samples were collected from two seabird species; only one of 50 Mottled Petrels (2.0%) was positive for the presence of Erysipelothrix spp. Our findings confirm that burrowing seabirds are possible reservoirs of E. rhusiopathiae on both islands studied and may be the source of spillover to other species on the island. The differences in observed prevalence suggest the species composition of the reservoir of E. rhusiopathiae may vary geographically.

Бесконтактный метод определения пола такахе Porphyrio hochstetteri (Rallidae, Gruiformes) по абрису клюва: графический и статистические приемы

В статье приводятся результаты применения метода бесконтактного определения пола птиц по профильному абрису головы к редкому нелетающему пастушку из Новой Зеландии - такахе. Графический этап позволил выявить визуальные различия в профильных абрисах клюва самцов и самок. Достоверность найденных различий была подтверждена набором статистических приемов анализа, показавших почти 100-процентную эффективность предложенного метода. Here we present the results of applying the method of non-contact sexing of birds by the profile beak outlines to a rare flightless rallid from New Zealand - takahē. The graphic stage of the method made it possible to identify visual differences in the profile outlines of the beak of males and females. The reliability of the differences found was confirmed by a set of statistical analysis techniques that showed almost 100 percent effectiveness of the proposed method.

Genomic Epidemiology and Management of Salmonella in Island Ecosystems Used for Takahe Conservation.

Translocation and isolation of threatened wildlife in new environments may have unforeseen consequences on pathogen transmission and evolution in host populations. Disease threats associated with intensive conservation management of wildlife remain speculative without gaining an understanding of pathogen dynamics in meta-populations and how location attributes may determine pathogen prevalence. We determined the prevalence and population structure of an opportunistic pathogen, Salmonella, in geographically isolated translocated sub-populations of an endangered New Zealand flightless bird, the takahe (Porphyrio hochstetteri). Out of the nine sub-populations tested, Salmonella was only isolated from takahe living on one private island. The apparent prevalence of Salmonella in takahe on the private island was 32% (95% CI 13-57%), with two serotypes, Salmonella Mississippi and Salmonella houtenae 40:gt-, identified. Epidemiological investigation of reservoirs on the private island and another island occupied by takahe identified environmental and reptile sources of S. Mississippi and S. houtenae 40:gt- on the private island. Single nucleotide polymorphism analysis of core genomes revealed low-level diversity among isolates belonging to the same serotype and little differentiation according to host and environmental source. The pattern observed may be representative of transmission between sympatric hosts and environmental sources, the presence of a common unsampled source, and/or evidence of a recent introduction into the ecosystem. This study highlights how genomic epidemiology can be used to ascertain and understand disease dynamics to inform the management of disease threats in endangered wildlife populations.

Microbial Genomics of a Host-Associated Commensal Bacterium in Fragmented Populations of Endangered Takahe.

Isolation of wildlife into fragmented populations as a consequence of anthropogenic-mediated environmental change may alter host-pathogen relationships. Our understanding of some of the epidemiological features of infectious disease in vulnerable populations can be enhanced by the use of commensal bacteria as a proxy for invasive pathogens in natural ecosystems. The distinctive population structure of a well-described meta-population of a New Zealand endangered flightless bird, the takahe (Porphyrio hochstetteri), provided a unique opportunity to investigate the influence of host isolation on enteric microbial diversity. The genomic epidemiology of a prevalent rail-associated endemic commensal bacterium was explored using core genome and ribosomal multilocus sequence typing (rMLST) of 70 Campylobacter sp. nova 1 isolated from one third of the takahe population resident in multiple locations. While there was evidence of recombination between lineages, bacterial divergence appears to have occurred and multivariate analysis of 52 rMLST genes revealed location-associated differentiation of C. sp. nova 1 sequence types. Our results indicate that fragmentation and anthropogenic manipulation of populations can influence host-microbial relationships, with potential implications for niche adaptation and the evolution of micro-organisms in remote environments. This study provides a novel framework in which to explore the complex genomic epidemiology of micro-organisms in wildlife populations.

Using a common commensal bacterium in endangered Takahe as a model to explore pathogen dynamics in isolated wildlife populations.

Predicting and preventing outbreaks of infectious disease in endangered wildlife is problematic without an understanding of the biotic and abiotic factors that influence pathogen transmission and the genetic variation of microorganisms within and between these highly modified host communities. We used a common commensal bacterium, Campylobacter spp., in endangered Takahe (Porphyrio hochstetteri) populations to develop a model with which to study pathogen dynamics in isolated wildlife populations connected through ongoing translocations. Takahe are endemic to New Zealand, where their total population is approximately 230 individuals. Takahe were translocated from a single remnant wild population to multiple offshore and mainland reserves. Several fragmented subpopulations are maintained and connected through regular translocations. We tested 118 Takahe from 8 locations for fecal Campylobacter spp. via culture and DNA extraction and used PCR for species assignment. Factors relating to population connectivity and host life history were explored using multivariate analytical methods to determine associations between host variables and bacterial prevalence. The apparent prevalence of Campylobacter spp. in Takahe was 99%, one of the highest reported in avian populations. Variation in prevalence was evident among Campylobacter species identified. C. sp. nova 1 (90%) colonized the majority of Takahe tested. Prevalence of C. jejuni (38%) and C. coli (24%) was different between Takahe subpopulations, and this difference was associated with factors related to population management, captivity, rearing environment, and the presence of agricultural practices in the location in which birds were sampled. Modeling results of Campylobacter spp. in Takahe metapopulations suggest that anthropogenic management of endangered species within altered environments may have unforeseen effects on microbial exposure, carriage, and disease risk. Translocation of wildlife between locations could have unpredictable consequences including the spread of novel microbes between isolated populations.

Network Analysis of Translocated Takahe Populations to Identify Disease Surveillance Targets

Social network analysis is being increasingly used in epidemiology and disease modeling in humans, domestic animals, and wildlife. We investigated this tool in describing a translocation network (area that allows movement of animals between geographically isolated locations) used for the conservation of an endangered flightless rail, the Takahe (Porphyrio hochstetteri). We collated records of Takahe translocations within New Zealand and used social network principles to describe the connectivity of the translocation network. That is, networks were constructed and analyzed using adjacency matrices with values based on the tie weights between nodes. Five annual network matrices were created using the Takahe data set, each incremental year included records of previous years. Weights of movements between connected locations were assigned by the number of Takahe moved. We calculated the number of nodes (i(total)) and the number of ties (t(total)) between the nodes. To quantify the small-world character of the networks, we compared the real networks to random graphs of the equivalent size, weighting, and node strength. Descriptive analysis of cumulative annual Takahe movement networks involved determination of node-level characteristics, including centrality descriptors of relevance to disease modeling such as weighted measures of in degree (k(i)(in)), out degree (k(i)(out)), and betweenness (B(i)). Key players were assigned according to the highest node measure of k(i)(in), k(i)(out), and B(i) per network. Networks increased in size throughout the time frame considered. The network had some degree small-world characteristics. Nodes with the highest cumulative tie weights connecting them were the captive breeding center, the Murchison Mountains and 2 offshore islands. The key player fluctuated between the captive breeding center and the Murchison Mountains. The cumulative networks identified the captive breeding center every year as the hub of the network until the final network in 2011. Likewise, the wild Murchison Mountains population was consistently the sink of the network. Other nodes, such as the offshore islands and the wildlife hospital, varied in importance over time. Common network descriptors and measures of centrality identified key locations for targeting disease surveillance. The visual representation of movements of animals in a population that this technique provides can aid decision makers when they evaluate translocation proposals or attempt to control a disease outbreak.

HUMERAL REMODELING AND SOFT TISSUE INJURY OF THE WINGS CAUSED BY BACKPACK HARNESSES FOR RADIO TRANSMITTERS IN NEW ZEALAND TAKAHĒ (PORPHYRIO HOCHSTETTERI)

Backpack harnesses are commonly used to attach radio and satellite transmitters to a wide range of bird species for research and conservation management. They are an integral part of the conservation management of the New Zealand Takahē (Porphyrio hochstetteri), an endangered flightless rail. Radio transmitters mounted on backpack harnesses enable the birds to be tracked in their remaining native range of remote, mountainous Fiordland, New Zealand. We evaluated 26 Takahē retrospectively at necropsy by gross examination, radiography, and computed tomography to assess damage from the backpack harness. Ten birds that had never worn a harness had no evidence of wing injury. Of the 16 birds that had worn a harness, 10 (63%) had superficial soft tissue injury to skin or patagium or more severe injury, such as remodeling of the distal humerus at the harness cord-wing interface, or pathologic fractures. Such injuries are hypothesized to be associated with discomfort, increased risk of infection or fracture, and therefore reduced fitness. These findings have implications for all avian species deployed with backpack harnesses.

Use of Bayesian population viability analysis to assess multiple management decisions in the recovery programme for the Endangered takahe Porphyrio hochstetteri

AbstractPopulation modelling is an invaluable tool for identifying effective management strategies for threatened species whose populations are too small for experimental manipulation. Recently developed Bayesian approaches allow us to combine deterministic models with probability distributions to create stochastic models that account for uncertainty. We illustrate this approach in the case of the takahe Porphyrio hochstetteri, an Endangered flightless rail, which is supported by one of New Zealand's costliest recovery programmes. Using mark–recapture and logistic regression models implemented in a Bayesian framework we calculated demographic parameters for a fully stochastic population model based on 25 years of data collected from the last wild population of takahe in the Murchison Mountains, Fiordland. Our model results show that stoat trapping, captive rearing and cross-fostering of eggs/chicks in wild pairs all have a positive effect on takahe demography. If it were not for these management actions the Fiordland population would probably be declining (λ = 0.985; confidence interval, CI = 0.39–1.08), with a non-negligible risk of quasi-extinction (P = 16%) within 20 years. The captive rearing of eggs and chicks has been the main factor responsible for the positive growth observed during the last decade but in the future expanding stoat trapping to cover the entire Murchison Mountains would be the single most beneficial management action for the takahe population (λ = 1.038; CI = 0.86–1.10), followed by captive rearing (λ = 1.027; CI = 0.85–1.09).

A retrospective study of post-mortem examination findings in takahe (Porphyrio hochstetteri)

AIMS: To identify the major diseases or disease processes affecting both captive and wild populations of takahe (Porphyrio hochstetteri) in birds submitted for post-mortem examination between 1992 and 2007, and to survey archived wild dead takahe for the presence of Erysipelothrix rhusiopathiae. METHODS: Reports of 199 post-mortem examinations submitted between 1992 and 2007 were reviewed retrospectively. The reports comprised 56 eggs, 51 chicks up to 6 months of age, 13 sub-adults 6–18 months old, 74 adults and five birds where age was not recorded. Bone marrow flushed from the keel of 34 frozen adult takahe was assayed for the presence of E. rhusiopathiae, using PCR analysis. RESULTS: Of the eggs examined, 6/56 (11%) had no recorded diagnosis, 24/56 (43%) were infertile and 26/56 (46%) showed embryonic mortality at various stages. Excluding eggs, the cause of death could not be determined in 64/138 (46%) birds with a recorded age that were examined. Contributing factors for the low rate of diagnosis included advanced decomposition of many carcasses, the freezing of some birds prior to pathological investigation, long delays between recovery and submission for post-mortem examination, and variation in the extent of post-mortem examination and ancillary diagnostic testing. Common post-mortem examination findings in chicks included those related to cardiac disease [11/51 (22%)], infectious or inflammatory disease [9/51 (18%)] and trauma [7/51 (14%)]. In adult birds, the most common post-mortem examination findings were due to infectious or inflammatory disease [15/74 (20%)] including septicaemia due to E. rhusiopathiae [3/74 (7%)], followed by degenerative conditions due to diet, age and husbandry [9/74 (12%)]. Bacteria implicated in the causes of death included Escherichia coli, E. rhusiopathiae, Salmonella enterica serovar Typhimurium, and Pseudomonas aeruginosa. Only 1/34 (3%) of the frozen carcass examined using PCR was positive for E. rhusiopathiae. CONCLUSIONS: This study highlights a need for improved recovery, storage and submission of dead takahe for pathological examination; consistency in post-mortem examination, ancillary testing and recording of findings; and finally, regular communication between wildlife pathologists, conservation workers and representatives of Ngai Tahu.

Low genetic diversity and small population size of Takahe Porphyrio hochstetteri on European arrival in New Zealand

The rediscovery of the Takahe Porphyrio hochstetteri in 1948 in the remote mountains of Fiordland, New Zealand, has been described as one of the greatest moments in ornithological history. The subsequent management of the population has become a model for avian recovery programmes, yet questions still remain regarding the population size at the time of, and prior to, its rediscovery. We used 20 microsatellite markers to genotype samples of the three surviving museum specimens (1849–1898) collected prior to the initial declaration of extinction to estimate levels of genetic diversity and effective population size. These estimates were compared with equivalent estimates from DNA samples of three specimens preserved at the time of rediscovery (1949) and with 20 contemporary samples. Using rarefaction simulations to account for the limited sample sizes, the results suggest that only slightly more genetic diversity (allelic diversity and numbers of polymorphic loci) existed in the earliest Takahe sampled and that levels of genetic diversity at the time of rediscovery were very similar to those today. Effective population size estimates showed a similar pattern. Contemporary samples from a widespread congener to Takahe, the Pukeko Porphyrio porphyrio, showed consistently higher levels of genetic diversity and greater effective population size, even after equivalent rarefaction to the same small sample sizes available for Takahe. It is likely that the population size of Takahe in Fiordland at the time of European arrivals in the 1800s was similar to its current size. These results provide molecular support for the hypothesis that Takahe were common throughout most coastal and eastern parts of the South Island of New Zealand before being hunted to extinction in these regions by early Maori, and persisted as a relatively small and isolated population in Fiordland where they may never have been very common. This is in marked contrast to other New Zealand endemic birds found in Fiordland, such as the Kakapo Strigops habroptilus and several forest passerines, which remained relatively numerous until the time of European arrival before undergoing rapid declines thereafter.

Sporormiella as a proxy for non-mammalian herbivores in island ecosystems

Spores of the dung-fungi Sporormiella are routinely used as a proxy for past megaherbivore biomass and to pinpoint the timing of extinctions. Further ecological insight can also be gained into the impacts that followed initial human arrival in a region through correlation of spore abundance with other proxies (e.g. pollen, charcoal). Currently, the use of Sporormiella as a palaeoecological proxy has been restricted to landmasses where large-herbivore guilds are dominated by mammals. Here, we use New Zealand as a case study to show that the method can also be applied effectively to islands dominated by large avian herbivores. We examine 44 dung samples from 7 localities to show that Sporormiella spores were widely distributed in the dung of endemic avian herbivores (South Island takahe ( Porphyrio hochstetteri), kakapo ( Strigops habroptilus), and several species of extinct moa, identified by ancient DNA analysis). In addition, we show that Sporormiella spores in a forest soil core from the Murchison Mountains, South Island, accurately trace the post-settlement decline of native avian herbivores, and combined with high-resolution radiocarbon dating reveal severely reduced local herbivore populations by the late 17th Century AD. The spores also trace the subsequent spread of Red deer ( Cervus elaphus) introduced to the area in the early 20th Century AD. Our results suggest Sporormiella spores may provide a useful new tool for examining extinctions on numerous islands where terrestrial herbivore guilds were dominated by birds or reptiles. Our findings also highlight the need to consider entire herbivore communities (including birds and reptiles) when examining Late Pleistocene continental Sporormiella records, where the focus has often been tracing the decline of populations of large mammals.

The imprecision of heterozygosity-fitness correlations hinders the detection of inbreeding and inbreeding depression in a threatened species

In nonpedigreed wild populations, inbreeding depression is often quantified through the use of heterozygosity-fitness correlations (HFCs), based on molecular estimates of relatedness. Although such correlations are typically interpreted as evidence of inbreeding depression, by assuming that the marker heterozygosity is a proxy for genome-wide heterozygosity, theory predicts that these relationships should be difficult to detect. Until now, the vast majority of empirical research in this area has been performed on generally outbred, nonbottlenecked populations, but differences in population genetic processes may limit extrapolation of results to threatened populations. Here, we present an analysis of HFCs, and their implications for the interpretation of inbreeding, in a free-ranging pedigreed population of a bottlenecked species: the endangered takahe (Porphyrio hochstetteri). Pedigree-based inbreeding depression has already been detected in this species. Using 23 microsatellite loci, we observed only weak evidence of the expected relationship between multilocus heterozygosity and fitness at individual life-history stages (such as survival to hatching and fledging), and parameter estimates were imprecise (had high error). Furthermore, our molecular data set could not accurately predict the inbreeding status of individuals (as 'inbred' or 'outbred', determined from pedigrees), nor could we show that the observed HFCs were the result of genome-wide identity disequilibrium. These results may be attributed to high variance in heterozygosity within inbreeding classes. This study is an empirical example from a free-ranging endangered species, suggesting that even relatively large numbers (>20) of microsatellites may give poor precision for estimating individual genome-wide heterozygosity. We argue that pedigree methods remain the most effective method of quantifying inbreeding in wild populations, particularly those that have gone through severe bottlenecks.

Inbreeding Depression Accumulation across Life‐History Stages of the Endangered Takahe

Studies evaluating the impact of inbreeding depression on population viability of threatened species tend to focus on the effects of inbreeding at a single life-history stage (e.g., juvenile survival). We examined the effects of inbreeding across the full life-history continuum, from survival up to adulthood, to subsequent reproductive success, and to the recruitment of second-generation offspring, in wild Takahe ( Porphyrio hochstetteri ) by analyzing pedigree and fitness data collected over 21 breeding seasons. Although the effect size of inbreeding at individual life-history stages was small, inbreeding depression accumulated across multiple life-history stages and ultimately reduced long-term fitness (i.e., successful recruitment of second-generation offspring). The estimated total lethal equivalents (2B) summed across all life-history stages were substantial (16.05, 95% CI 0.08-90.8) and equivalent to an 88% reduction in recruitment of second-generation offspring for closely related pairs (e.g., sib-sib pairings) relative to unrelated pairs (according to the pedigree). A history of small population size in the Takahe could have contributed to partial purging of the genetic load and the low level of inbreeding depression detected at each single life-history stage. Nevertheless, our results indicate that such "purged" populations can still exhibit substantial inbreeding depression, especially when small but negative fitness effects accumulate across the species' life history. Because inbreeding depression can ultimately affect population viability of small, isolated populations, our results illustrate the importance of measuring the effects of inbreeding across the full life-history continuum.

Cover Caption

Conservation BiologyVolume 24, Issue 6 p. i-i Conservation Biology Cover Caption First published: 11 November 2010 https://doi.org/10.1111/j.1523-1739.2010.01614.xAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Abstract Cover: The Takahe (Porphyrio hochstetteri), once widespread throughout New Zealand, was thought to be extinct by the end of the 1800s. In 1948 a remnant population was rediscovered in a remote region of the country's South Island. As of 2007, 72 birds descended from 18 founders were distributed across 4 islands off the coast of New Zealand. Grueber et al. (pages 1617-1625) evaluated the effect of inbreeding depression across all life-history stages of the Takahe. Although levels at each stage were low, accumulated inbreeding depression ultimately reduced long-term fitness. These results suggest that even species with high historical levels of inbreeding can lose fitness as a result of recent inbreeding. Volume24, Issue6December 2010Pages i-i RelatedInformation

Isolation and characterization of microsatellite loci from the endangered New Zealand takahe (Gruiformes; Rallidae; Porphyrio hochstetteri)

Nineteen polymorphic microsatellite loci were characterized from the endangered takahe (Porphyrio hochstetteri). Like many of New Zealand's other native avian species, levels of polymorphism were low, with variation detected at only 19 of 110 (17.3%) loci, and most polymorphic loci (78.9%) were diallelic (mean number of alleles=2.3). Despite these low levels of variation, the microsatellites developed here will be useful for parentage assignment for confirming pedigrees, and investigating relationships between genetic variation, pedigree-based inbreeding and reproductive success in this highly endangered species.

Quantifying and managing the loss of genetic variation in a free-ranging population of takahe through the use of pedigrees

Pedigree analysis has clear benefits for the genetic management of threatened populations through the evaluation of inbreeding, population structure and genetic diversity. The use of pedigrees is usually restricted to captive populations and few examples exist of their exclusive use in managing free-ranging populations. One such example is the management of the takahe (Porphyrio hochstetteri), a highly endangered, flightless New Zealand rail at risk from introduced mammalian predators and habitat loss. During the 1980’s and 90’s, as part of the takahe recovery programme, birds were translocated from the sole remnant population in Fiordland to four offshore islands from which introduced predators had been eradicated. The subsequent “island” population, now numbering 83 and thought to be at carrying capacity, has been closely monitored since founding. Detailed breeding records allow us to analyse the island pedigree, which is up to 7 generations deep. Gene-drop analysis indicated that 7.5% of genetic diversity has been lost over the relatively short timeframe since founding (2.1 generations on average; total genetic founders = 31) due to both a failure to equalise founder representation early on and subsequent disproportionate breeding success (founder equivalents = 12.5; founder genome equivalents = 6.6). A high prevalence of close inbreeding will have also impacted on genetic diversity. Predictions from pedigree modelling suggest that 90% genetic diversity will be maintained for only 12 years, but by introducing a low level of immigration from the Fiordland population and permitting the population to grow, 90% GD could be maintained over the next 100 years. More generally, the results demonstrate the value of maintaining pedigrees for wild populations, especially in the years immediately after a translocation event.

The nutritional value of cocksfoot (Dactylis glomerata L.), midribbed snow‐tussock (Chionochloa pallens Zotov), and red tussock (Chionochloa rubra Zotov) for the takahe (Porphyrio hochstetteri Meyer)

A feeding trial was carried out to determine the nutritional value of midribbed snow‐tussock (Chionochloa pallens Zotov), red tussock (Chionochloa rubra Zotov), and cocksfoot (Dactylis glomerata L.) for the takahe (Porphyrio hochstetteri Meyer), an endangered flightless herbivorous rail endemic to New Zealand. Three captive‐reared birds were fed each of the diets for 11 days, during which food intake, faecal plus urinary output, nutrient balances and coefficients of absorption/retention of energy, nitrogen, soluble sugars, starch, and mineral elements were determined. The mean dry matter (DM) intake was of the order cocksfoot > midribbed snow‐tussock > red tussock. The proportions of total soluble sugars absorbed from all grasses were in the range 0.8–0.96, whilst the proportions of energy absorbed (0.24, 0.17, ‐0.29) and nitrogen retained (0.19, 0.15, ‐0.04) from all grasses were low. Cocksfoot was nutritionally superior to the tussocks for most parameters measured, suggesting that islands with pasture habitat should adequately meet the requirements of takahe.