Abstract: The last remaining natural population of the critically endangered takahe (Porphyrio hochstetteri) is confined to the Murchison Mountains in Fiordland, New Zealand. This mainland population contains about half of the c. 300 remaining takahe and benefits from one of the costliest recovery programmes in the country. Management activities include deer culling, stoat trapping, nest manipulation (e.g. removal of infertile eggs) and captive rearing of chicks. To determine what effect this intensive management has had on the recovery of the Fiordland takahe population, we modelled 25 years of survival and breeding success data as a function of environmental factors (e.g. precipitation, temperature, beech seedfall, tussock flowering) and specific management activities (egg manipulation, captive rearing, stoat control). Annual adult survival, estimated at 78% (credibility interval (CI) = 75–81%), is significantly increased to 85% (76–92% CI) in presence of stoat trapping, but is still low relative to introduced takahe populations on offshore islands and other large New Zealand bird species in predator-free environments. This suggests that the harsh environment of Fiordland may be suboptimal habitat in terms of survival for takahe. On the other hand, reproductive output in Fiordland is similar to that for introduced island populations, and is improved even further by management. Number of chicks per pair fledged with nest manipulation and captive rearing is estimated at 0.66 compared with 0.43 in the absence of nest management. The difference is explained mainly by low fledging success in the wild, especially for double clutches, which justifies the practice of removing one of two viable eggs and transferring it to a captive-rearing facility. The results of this study indicate that current management activities such as stoat trapping and captive rearing have a strong positive effect on population growth of the Murchison Mountains takahe population.
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Pathogenic diseases are increasingly recognised as a challenge to the conservation of wildlife. Complex host-pathogen relationships and transmission dynamics in wild populations can limit our understanding of how pathogens contribute to the decline and endangerment of wildlife. Endangered wildlife populations maintained in reserves present a unique opportunity to investigate wildlife host- microbe relationships in a controlled semi-natural environment where diversity, abundance and the movement of species are restricted. The aim of this study was to investigate the prevalence and molecular differentiation of enteric bacteria carried by endangered takahe (Porphyrio hochstetteri). Through the use of network analysis and molecular epidemiology, the study explored the effects of geographic isolation and translocation on the prevalence, transmission and evolution of Campylobacter and Salmonella spp. within fragmented populations of takahe.
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Campylobacter spp. are enteric bacteria able to colonise a diverse range of hosts (Kwan et al. 2008), including multiple avian species with variable prevalence reported depending upon species, location and method used (Waldenstrom & Griekspoor 2014). Although Campylobacter spp. are often harmless commensals in wildlife, they can be pathogens when hosts are exposed to isolates from another species. An infection experiment demonstrated a marked decrease in the body mass of European robins (Erithacus rubecula) following inoculation with a Campylobacter jejuni isolate derived from another wild bird species (Waldenstrom et al. 2010). Previous studies have highlighted the exceptionally high prevalence of Campylobacter spp. isolated from takahe (Porphyrio hochstetteri) (Chapter 3). Takahe are an endemic endangered New Zealand flightless rail (BirdLife International 2013) whose populations have been heavily manipulated through conservation actions. Preservation of the species relies on the frequent translocation of individuals between remote sanctuaries (Wickes et al. 2009). This study describes the prevalence of Campylobacter spp. in five vertebrate orders within an island ecosystem used for the conservation of takahe. To explore bacterial transmission between takahe and potential reservoirs, comparative analyses of 52 of the 53 conserved ribosomal protein genes used in ribosomal multi-locus sequence typing (rMLST) schemes (Jolley et al. 2012) were used for the discrimination and differentiation of Campylobacter spp. genomes isolated from hosts on Maud Island, New Zealand. To our knowledge, this is the first study to use genomic comparisons of rMLST genes to investigate the epidemiology of a commensal bacterium within abundant and endangered communities inhabiting the same island ecosystem.
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3. A review of fresh and archived faecal samples to establish the geographic distribution of Eimeria sp. in South Island Takahē (Porphyrio hochstetteri) and variation in faecal oocysts counts over three years at a central breeding location ................................. 53
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This is the first description of an Eimeria sp. protozoa from a Takahē host. In line with currently accepted guidelines, new species descriptions should be compared with those isolated from host species within the same genus or family (Duszynski & Wilber, 1997). There are five Eimeria species described from hosts in the family Rallidae, key features of the description of 3 of these species is presented in Table 2.2. Unfortunately, the descriptions of the remaining two species are not published in English and weren’t available for comparison. Eimeria paludosa has been isolated from several hosts within this family including the Purple Swamphen (Porphyrio porphyrio) which belongs to the same genus as the Takahē. A major morphological characteristic of E. paludosa is the presence of two distinct micropyles (McAllister & Upton, 1990). However, in the newly described oocyst the micropyle is absent. A further distinction is E. paludosa has a single refractile body per sporozoite in contrast to the species reported here which has two. Eimeria porphyrulae and E. neinei oocysts are considerably larger than the currently described species. There is some overlap between the size the new species and E. crecis, described from the corncrake (Crex crex) (Jeanes et al., 2013). Like the new species the micropyle is absent, however E. crecis also lacks an oocyst residuum and was spherical in shape (L:W 1.1) in direct contrast to this new ovoid species. Consequently, this morphological description of an Eimeria sp. from the Takahē host is distinct from other species previously described from family: Rallidae. Historically description of new protozoal species was based on descriptive characteristics of the sporulated oocyst and host factors, as described here for the proposed new Takahē coccidia. However, increasingly molecular description is being added to morphological description for the characterisation of species (Adl et al., 2007; Jeanes et al., 2013) Molecular analysis was outside the scope of the current project but would now be required to complete the description of this new Eimeria species.
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The second level investigated the phenotypes of related sequence types (ST) with generalist and specialist lifestyles and compared them at 42℃ and 22℃ on the basis of carbon source utilisation in Biolog phenotypic microarrays. The isolates utilised a total of 29 carbon sources in a pattern that clustered them together on the basis of ST at 42 ℃ more than lifestyle and host. At 22 ℃ they utilised a limited palette of carbon sources (9) related to the tricarboxylic acid cycle (TCA). The third level, used genomic comparisons to identify a putative new species C. sp. nov. 4 spp. in the Australian purple swamphen (Porphyrio porphyrio melanotus ). Overall, the pattern of relationship between isolates associated with the pukeko (Porphyrio porphyrio melanotus), takahe (Porphyrio hochstetteri) and the Australian swamphen isolates suggested a recent common ancestor and then divergence after separation. Despite high levels of recombination in C.jejuni, the genomes grouped by clonal complex and ST, this suggests there are factors restricting regular recombination between more distant C. jejuni STs. The draft genomes for the wild-bird and agricultural-related isolates clustered by lineages in a host(s).
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Formerly placed alone in the genus Notornis, it is now accepted that takahe are very close relatives of pukeko or purple swamphens (Porphyrio porphyrio L.) having diverged from a common ancestor approximately two million years ago (Olson, 1973; Sibley and Ahlquist, 1990). The two species share many morphological and behavioural characteristics although pukeko are smaller, have relatively longer appendages, are capable of flight, and tend to live in communal groups (Jamieson, 1994). Since their invasion of New Zealand from Australia within the past 800 years (Millener, 1981), pukeko have flourished in lowland swamps and moist pastures. Unlike takahe, they have been able to expand their distribution and numbers since European colonisation and the subsequent clearing of extensive areas of forests for agriculture. The pukeko’s success is due not only to their ability to fly and better predator awareness and defence behaviour (Bunin and Jamieson, in press), but may also relate to their high reproductive rate. Pukeko usually lay five eggs compared to the takahe’s two and can produce multiple broods within a season, while takahe only renest if the first clutch fails and generally only raise a maximum of one chick per year.
Bronze-winged Jacana Metopidius indicus and Pheasant-tailed Jacana Hydrophasianus chirurgus were spotted at Jyoti Sarovar alone, the only pond with lotuses. The vegetation cover of lotuses provides suitable feeding, nesting, and breeding habitat for herons, moorhens, and jacanas. Purple Swamphen Porphyrio porphyrio, a common resident species, was observed only in weedy marsh areas flanking the sacred pond of Jyoti Sarovar, where there were frequent human activities; this bird species may be a bio-indicator of enhanced weed infestation and increased vegetation cover in the wetlands of Haryana (Kumar et al. 2016). Waders, shorebirds, Purple Moorhen, and wagtails were also observed foraging in the irrigated wheat and paddy fields flanking the sacred ponds in rural habitats (Jyoti Sarovar and Baan Ganga). This observation is consistent with earlier reports, where foraging by aquatic birds outside the wetlands in surrounding agriculture fields has been recorded (Lane & Fujioka 1998; Mukherjee et al. 2002; Urfi 2003; Jha 2013; Kumar et al. 2016).
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Ryan CJ, Jamieson IG 1998. Estimating the home range and caring capacity for takahe (Porphyrio mantelli) on predator-free offshore islands: implications for future management. New Zealand Journal of Ecology 22: 17–24. Bunin JS, Jamieson IG, Eason D 1997. Low reproductive success of the endangered takahe (Porphyrio mantelli) on offshore island refuges in New Zealand. Ibis 139: 144–151. Jamieson IG 1997. Testing reproductive skew models in a communally breeding bird, the pukeko (Porphyrio porphyrio). Proceedings of the Royal Society of London: Series B 264: 335–340.
A total of 50 sites were included in this study. A site was defined as a 40m long transect, based on Crossland et al. (2005) and Bradfield's (2005) research. The site area extended 1m each side of the stream edge, and up to 60cm above the water level. The locations and individual ID numbers of the sites are shown in Figure 2.1 and Appendix II, while the descriptions of the sites are available in Appendix III. To use available data on past distribution and relative abundance of L. hochstetteri in the Waitakere Ranges, 36 sites surveyed previously by Bradfield (2005) for the ARC were included in the present study. Two previously established sites were visited, but not included; “Opanuku 2” was not surveyed because of difficult access and flooding upon visit, and was replaced by a section of stream in the same catchment about 100m away; “Piha 4” was dry due to a landslide that caused subterranean water flow and was replaced by an adjacent section of stream. These sites retained the original name given by Bradfield (2005), but were considered as new sites as no previous data were available. One site (“Anawhata 4”) was not included as it had been recently and frequently surveyed by Peter King (La Trobe Mainland Island restoration project) as part of research on the effects of predator control on L. hochstetteri populations.
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In New Zealand, the pukeko (Porphyrio p. melan- otus) (Rallidae) inhabits wet lowlands and breeds in swamps, but uses such habitats as pasture, crops, farm ponds, road verges and forest margins which collectively provide a more diverse environment and offer feeding opportunities unavailable before the large-scale lowland clearance and swamp drainage of the last 150 years. In Australia, it also ventures from still and moving water into open pastures to feed (Slater, 1970; Reader's Digest, 1976; Briggs, 1979) as does the Tasmanian native hen (Gallinula mortierii) (Ridpath, 1972). Changes in land use could be locally advantageous to pukeko, as claimed by Guthrie- Smith (1953), and affect population levels (Carroll, 1969) but by what process is not clear, although social parameters are responsive to habitat (Craig, 1979) and changes in grouping and activity could occur.
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Summary: Predator-free offshore islands play an important role in the conservation of many of New Zealand’s endemic species. Takahe (Porphyrio mantelli) have small populations established on four offshore islands and although hatching success is lower than that of the wild mainland population in Fiordland, juvenile and adult survival is high and populations are growing exponentially. Accurate estimates of home range size and potential carrying capacities are therefore essential for the future management of the population as a whole. The mean home range size of takahe pairs in one study population on Mana Island (217 ha) was 2.8 ± 1.9 ha. The island was assessed for current and maximum available area for takahe and the potential carrying capacity was estimated at 22 - 53 pairs. Current and maximum available areas were also used to calculate carrying capacities on each of three other islands using two different estimates of mean home range size for Maud Island (7 - 34 pairs) and Kapiti Island (5 - 33 pairs) and one estimate of home range size for Tiritiri Matangi Island (25 pairs). A model of the population growth of takahe on islands predicted that estimated carrying capacities would be reached between 1997 and 2009. The urgency of planning to make use of the considerable potential of island populations of takahe is stressed.