Population genetic and behavioural variation of the two remaining colonies of Providence petrel (<Emphasis Type="Italic">Pterodroma solandri</Emphasis>)

Knowledge of the dispersal capacity of species is crucial to assess their extinction risk, and to establish appropriate monitoring and management strategies. The Providence petrel (Pterodroma solandri) presently breeds only at Lord Howe Island (~32,000 breeding pairs) and Phillip Island-7 km south of Norfolk Island (~20 breeding pairs). A much larger colony previously existed on Norfolk Island (~1,000,000 breeding pairs) but was hunted to extinction in the 18th Century. Differences in time of return to nesting sites are presently observed between the two extant colonies. Information on whether the Phillip Island colony is a relict population from Norfolk Island, or a recent colonization from Lord Howe Island, is essential to assess long-term sustainability and conservation significance of this small colony. Here, we sequenced the mitochondrial cytochrome b gene and 14 nuclear introns, in addition to genotyping 10 microsatellite loci, to investigate connectivity of the two extant P. solandri populations. High gene flow between populations and recent colonization of Phillip Island (95 % HPD 56–200 ya) are inferred, which may delay or prevent the genetic differentiation of these insular populations. These results suggest high plasticity in behaviour in this species and imply limited genetic risks surrounding both the sustainability of the small Phillip Island colony, and a proposal for translocation of Lord Howe Island individuals to re-establish a colony on Norfolk Island.     

Príncipe island hawksbills: Genetic isolation of an eastern Atlantic stock

The hawksbill turtle is a critically endangered species that has been extensively exploited for centuries. Príncipe Island off western Africa harbours one of the species' major nesting populations in the eastern Atlantic, as well as hosting year-round foraging aggregations of juveniles, subadults and adult males. To gain insight into the population's genetic structure and relationships with regional stocks, we analysed mitochondrial DNA (mtDNA) sequences of nesting females (N = 9), foraging adult females (N = 11), adult males (N = 32), subadults (N = 15) and juveniles (N = 80). The nesting population was found to be fixed for a single haplotype (EATL), which had been previously reported in both western and eastern Atlantic hawksbill foraging sites but had no known rookery source prior to this study. Thus it is now possible to confirm the westward transoceanic movement by hawksbills originating from Príncipe Island. Our analyses demonstrated that the Príncipe Island nesting colony is genetically distinct from breeding populations in the western Atlantic and is phylogenetically linked with Indo-Pacific hawksbill clades, suggesting that Príncipe Island was most likely colonised by migrants from the Indian Ocean via the Cape of Good Hope in southern Africa. Mixed stock analyses revealed that the eastern Atlantic appears to be the primary foraging area for Príncipe hawksbills (75%) while most of the foraging juveniles in Príncipe waters originate from the Príncipe rookery (84%). Furthermore, the presence of Caribbean haplotypes at low frequencies (< 5%) suggests that eastward transatlantic movements by juveniles to distant foraging and developmental habitats also take place. Depleted hawksbill populations in the eastern Atlantic combined with the low genetic variability and high genetic distinctiveness found in the Príncipe nesting and foraging aggregations with respect to the western Atlantic, underscore the high degree of isolation and vulnerability of this eastern Atlantic stock. These characteristics are highly relevant for the development of effective conservation programmes and highlight the urgent need to consolidate international cooperation across regional boundaries.     

Phylogeography of <Emphasis Type="Italic">Leiopelma hochstetteri</Emphasis> reveals strong genetic structure and suggests new conservation priorities

Leiopelma hochstetteri belongs to a singular anuran lineage endemic to New Zealand that diverged from other frogs about 200 million years ago. The species now is reduced to a series of isolated populations in the northern half of the North Island and Great Barrier Island. We have used mitochondrial and nuclear sequence data to examine the genetic affinities of extant populations of L. hochstetteri. Phylogenetic reconstructions reveal that populations are highly structured. Each of the geographically isolated populations harbours independent mtDNA lineages as well as different degrees of nuDNA differentiation. Moreover, molecular dating reveals that this structure originated in the early Pleistocene. This pattern of genetic structure likely results from unfavourable climatic conditions during the Pleistocene combined with the low dispersal ability of the species. Isolated populations in forested refugia existed even in the southern part of the distribution of the species during glacial cycles. Previously published variation in chromosome numbers and isozyme data are consistent with the new evidence. We identified 13 evolutionary significant units (ESUs) that should serve as the focus for future management and conservation of this species.     

Cavity use and breeding biology of endangered Bahama Swallows (Tachycineta cyaneoviridis): implications for conservation

Bird populations, especially on islands, have declined or gone extinct due to overhunting, habitat loss and fragmentation, and adverse effects of the introduction of non-native species. Bahama Swallows (Tachycineta cyaneoviridis), endangered secondary cavity nesters that breed on only three islands in the northern Bahamas, are an island species with a declining population, but the causes of this decline are unknown. During four breeding seasons on Great Abaco Island (2014–2017), we identified cavity-nesting resources used by breeding swallows in native pine forest and other habitats, and estimated phenology and breeding parameters from a subset of nests. Bahama Swallows nest in cavities in a variety of structures, but rely most on woodpecker-excavated cavities in pine snags and utility poles. Swallows nesting in cavities in pine snags had higher fledging success (92%) than those nesting in cavities in utility poles (50–62%), which were concentrated in non-pine habitat that may expose swallows to predation and increased competition for nest cavities from other species. The high reproductive success of Bahama Swallows nesting in the pine forest indicates that the decline in population cannot be attributed to poor productivity on southern Great Abaco. However, our results suggest that the dependence of Bahama Swallows on cavities excavated by Hairy Woodpeckers (Dryobates villosus) for nesting sites may be a factor in their decline, and highlight the potential importance of the protection and management of pine forests in future efforts to ensure the survival of Bahama Swallows.     

Habitat selection in reintroduced bird populations: a case study of Stewart Island robins and South Island saddlebacks on Ulva Island

An understanding of the mechanisms influencing habitat selection in reintroduced bird populations is fundamental for successful translocation programmes. Plant species composition, abundance, structure and food availability are likely to influence animal movement and habitat choice, but few studies have evaluated their combined effect on habitat selection of translocated birds. Stewart Island robins (Petroica australis rakiura) and South Island saddlebacks (Philesturnus carunculatus carunculatus) are two threatened New?Zealand bird species that have been reintroduced to Ulva Island (Stewart Island). We hypothesised that their initial settlement patterns were driven by habitat quality. We tested this hypothesis by comparing habitat components between occupied and unoccupied habitats as the population grew after initial tanslocation. We also modelled probabilities of site selection as a function of the composition and structure of vegetation, availability of food (invertebrate composition) and nesting resources (cavity type). Founding pairs of both species first established territories in coastal habitat in the western part of the island, which is characterised by structurally complex broadleaved vegetation. Birds also selected sites with a greater abundance and diversity of food resources. Thus in the early stages of population establishment robins and saddlebacks appear to select high quality habitat that offers enhanced cover and foraging opportunities.     

Phylogeographic-based conservation implications for the New Zealand long-tailed bat, (<Emphasis Type="Italic">Chalinolobus tuberculatus</Emphasis>): identification of a single ESU and a candidate population for genetic rescue

The New Zealand long-tailed bat (Chalinolobus tuberculatus) is an endemic species threatened with extinction. Since the arrival of humans, massive deforestation has occurred and invasive mammalian predators were introduced. As a result, C. tuberculatus’ distribution shrank dramatically and became fragmented. To aid the management of the remaining populations, two Evolutionary Significant Units (ESUs) were designated: one on each of New Zealand’s main islands. We utilised mitochondrial sequence data (cytb, 703 bp) and 10 nuclear DNA microsatellite loci to reconstruct the demographic history of this species, to characterise the level of genetic diversity in remaining populations, and to assess the current connectivity between them. Our results indicate that the North Island, with the highest genetic diversity, served as a glacial refuge, with a loss of diversity following the path recolonization to the south of the South Island. However, our data are also consistent with continued, or at least very recent, genetic exchange between colonies across the species distribution. The only exception is the Hanging Rock colony on the east coast of the South Island, which appears to be isolated. Thus, there was no support for the previously designated ESUs. Signatures of past population declines were found in three colonies, the most extreme of which was found in Hanging Rock. Consequently, we recommend that it be genetically rescued via translocation from a donor population. In general, future management priorities should treat Chalinolobus tuberculatus as a single unit, focusing on maintaining connectivity between remaining populations, together with continued roost protection and pest control.     

Demographic effects of temperature‐dependent sex determination: will tuatara survive global warming?

Global climate change is of particular concern for small and isolated populations of reptiles with temperature-dependent sex determination because low genetic variation can limit adaptive response in pivotal temperatures, leading to skewed sex ratios. We explore the demographic consequences of skewed sex ratios on the viability of a tuatara population characterized by low genetic diversity. We studied the rare species of tuatara ( Sphenodon guntheri ) on the 4 ha North Brother Island in New Zealand over two nesting seasons and captured 477 individuals, with a 60% male bias in the adult population. Females first breed at 15 years and have extremely low rates of gravidity, producing clutches of three to eight eggs every 9 years. Simulations of the population using population viability analysis showed that the current population is expected to persist for at least 2000 years at hatchling sex ratios of up to 75% male, but populations with 85% male hatchlings are expected to become extinct within approximately 300 years (some eight generations). Incorporation of inbreeding depression increased the probability of extinction under male biased sex ratios, with no simulated populations surviving at hatchling sex ratios >75% male. Because recent models have predicted that climate change could lead to the production of all male S. guntheri hatchlings by 2085, we examined whether periodic intervention to produce mixed or female biased sex ratios would allow the population to survive if only males were produced in natural nests. We show that intervention every 2–3 years could buffer the effects of climate change on population sex ratios, but translocation to cooler environs might be more cost-effective. Climate change threatens tuatara populations because neither modified nesting behaviour nor adaptive response of the pivotal temperature can modify hatchling sex ratios fast enough in species with long generation intervals.     

Genetic analyses of the Asian longhorned beetle (Coleoptera,Cerambycidae, <Emphasis Type="Italic">Anoplophora glabripennis</Emphasis>), in North America,Europe and Asia

The Asian longhorned beetle, (Coleoptera, Cerambycidae, Anoplophora glabripennis (Motschulsky)), is endemic to China and Korea and an important invasive insect in North America and Europe. We analyzed mitochondrial DNA sequence data of invasive populations of A. glabripennis in North America and Europe, and microsatellite allele frequency data of beetles from North America. We show that populations in New York City and Long Island NY; New Jersey, Chicago, IL, and Toronto, Canada have limited genetic diversity compared to populations in China. In addition, the data suggest that separate introduction events were responsible for many of the populations in North America and for European populations in Austria, France, Germany and Italy. Populations on Long Island, NY are suspected to have been initiated by the transport of cut wood from New York City. A. glabripennis beetles found in Jersey City, NJ appear to be derived from an expansion of the New York City, NY population, whereas beetles found in Linden, NJ are an expansion from the Carteret, NJ population. Limited genetic diversity did not stop this invasive insect from establishing damaging populations in North America. Founders of introduced A. glabripennis populations in North America and Europe are likely derived from populations in China that are themselves invasive, rendering difficult the identification of source populations. Invasiveness in an insect’s natural range could be an important predictor of potential pest status of introduced populations.     

Lessons from the Tōhoku tsunami: A model for island avifauna conservation prioritization

Earthquake‐generated tsunamis threaten coastal areas and low‐lying islands with sudden flooding. Although human hazards and infrastructure damage have been well documented for tsunamis in recent decades, the effects on wildlife communities rarely have been quantified. We describe a tsunami that hit the world's largest remaining tropical seabird rookery and estimate the effects of sudden flooding on 23 bird species nesting on Pacific islands more than 3,800 km from the epicenter. We used global positioning systems, tide gauge data, and satellite imagery to quantify characteristics of the Tōhoku earthquake‐generated tsunami (11 March 2011) and its inundation extent across four Hawaiian Islands. We estimated short‐term effects of sudden flooding to bird communities using spatially explicit data from Midway Atoll and Laysan Island, Hawai'i. We describe variation in species vulnerability based on breeding phenology, nesting habitat, and life history traits. The tsunami inundated 21%–100% of each island's area at Midway Atoll and Laysan Island. Procellariformes (albatrosses and petrels) chick and egg losses exceeded 258,500 at Midway Atoll while albatross chick losses at Laysan Island exceeded 21,400. The tsunami struck at night and during the peak of nesting for 14 colonial seabird species. Strongly philopatric Procellariformes were vulnerable to the tsunami. Nonmigratory, endemic, endangered Laysan Teal (Anas laysanensis) were sensitive to ecosystem effects such as habitat changes and carcass‐initiated epizootics of avian botulism, and its populations declined approximately 40% on both atolls post‐tsunami. Catastrophic flooding of Pacific islands occurs periodically not only from tsunamis, but also from storm surge and rainfall; with sea‐level rise, the frequency of sudden flooding events will likely increase. As invasive predators occupy habitat on higher elevation Hawaiian Islands and globally important avian populations are concentrated on low‐lying islands, additional conservation strategies may be warranted to increase resilience of island biodiversity encountering tsunamis and rising sea levels.     

Effect of the blood-sucking mite

Pathological consequences of the blood-sucking mite Ornithonyssus bursa vary between species, with its impact ranging from no measurable effect, to significant blood loss and chick mortality. In New Zealand, where several bird species are known to be parasitised by O.bursa, the effect of this mite on host fitness is unclear, as few studies have been carried out. During a three-year study of the North Island robin Petroica longipes on Tiritiri Matangi Island, the prevalence of O. bursa in robin nests and on chicks and its impact on robin chick growth and survival was measured. The presence of mites was correlated with both time of the season and humidity of the habitat, with infestation being positively correlated with later nesting attempts and more humid microclimates. Robin chicks in infested nests were significantly smaller and fledged at an earlier age than chicks in nests where no mites were detected. Despite this effect, no significant difference in body size or survival was detected between the two groups at one month post-fledging. This was most likely because chicks from mite- infested nests compensated for their retarded growth once they left the nest environment. On mainland New Zealand, where ground-dwelling mammalian predators are present, chicks forced to leave the nest at an earlier age with less developed flying skills may be at an increased risk of predation.     

An extreme wandering leopard seal, <Emphasis Type="Italic">Hydrurga leptonyx</Emphasis>, at Pitcairn Island,central South Pacific

Leopard seals are distributed around the Antarctic continent principally between 50°S and 80°S though they are known to wander even farther north, particularly to Australia, New Zealand, South America, and South Africa, and several sub-Antarctic Islands. Seasonal movements of leopard seals have been correlated with seasonal changes in the distribution of sea ice with seals moving north as sea ice develops in spring and winter and southward toward the Antarctic continent as it melts in late autumn and winter. On August 9, 2013, an emaciated juvenile male leopard seal was observed swimming in Bounty Bay at Pitcairn Island (25°4′S, 130°6′W). It was found ashore at a boat ramp in the bay the next day. Because of the seal’s apparent distress, it was promptly shot and killed humanely by an island police officer and then dumped at sea before any measurements or additional observations could be made. We estimated the seal to be a 10-month-old pup, about 1.8–2 m long. The appearance of this leopard seal at Pitcairn Island is only slightly farther south than the most northern record (the Cook Islands, 21°25′S, 159°8′W) for the species, but it is the most remote occurrence yet documented worldwide and correlates with the all-time record for sea ice coverage in the Antarctic in winter 2013.     

Collapse of the invasive garden ant, <Emphasis Type="Italic">Lasius neglectus</Emphasis>, populations in four European countries

The invasive garden ant Lasius neglectus (Hymenoptera: Formicidae) has been spreading rapidly in Europe ever since the 1990s. This ant established enormous supercolonies in many European cities and poses a serious threat to the local native faunas. The spread of this species has not slowed down in the last decades, but in the recent years the sizes of the known L. neglectus populations have generally been declining or have stagnated. For 29 supercolonies checked in four countries, in 10 cases L. neglectus individuals have not been found on the former area of their occurrence. On the other hand, only two supercolonies have expanded. In this paper, we summarize these monitoring data collected by the personal independent, diligent monitoring activities of myrmecologists on populations of the invasive garden ant in Bulgaria, Hungary, Poland and Spain. The reasons for this collapse are thought to be: (1) depletion of the local resources, (2) gradation of pathogens and (social)parasites, (3) climatic factors, (4) intra-population mechanisms, (5) confrontation with highly competitive native species, and (6) lack of suitable nesting microhabitats. As similar phenomena were observed in the cases of supercolonies of other invasive ant species, it seems that they decline more generally than has been thought.     

Species limits and population differentiation in New Zealand snipes (Scolopacidae: <Emphasis Type="Italic">Coenocorypha</Emphasis>)

At least four species of New Zealand snipes (Coenocorypha) became extinct following the introduction of predatory mammals, and another two species suffered massive range reductions. To investigate species limits and population differentiation in six of the seven remaining offshore populations, we assayed variation in nine microsatellite loci and 1,980 base pairs of four mitochondrial DNA (mtDNA) genes. Genetic diversity in all populations except the largest one on Adams Island in the Auckland Islands was very low in both genomes. Alleles were fixed at many microsatellite loci and for single mtDNA haplotypes, particularly in the populations in the Chathams, Snares, Antipodes and Campbell Islands. Strong population structure has developed, and Chathams and Snares Islands populations are effectively genetically isolated from one another and from the more southern island populations. Based on reciprocal monophyly of lineages and their morphological distinctiveness we recommend that three phylogenetic species should be recognized, C. pusilla in the Chatham Islands, C. huegeli in the Snares Islands and C. aucklandica in the southern islands. The populations of C. aucklandica in the Auckland Islands, Antipodes Island and Campbell Island may warrant recognition as subspecies, and all should be managed as separate conservation units.     

Are green turtles globally endangered?

Aim  To examine the exploitation, recovery and current status of green turtles ( Chelonia mydas ) nesting at Ascension Island.
Location  Ascension Island (UK) (7°57' S, 14°22' W), South Atlantic Ocean.
Methods  We analysed records of the harvest of green turtles nesting at Ascension Island between 1822 and 1935, illustrating the decline in numbers over this period. Using a deterministic age-class structured model we predict the initial number of breeding females present in the population prior to the recorded harvest and compare this to our estimate of the current population based upon our recent annual surveys (1999–2004).
Results  Prior to 1822 we estimate the nesting population of green turtles to have been at least 19,000–22,000 individuals in order for the population to have survived the level of harvest recorded. From recent data (1999–2004), we estimate the current breeding population of green turtles at this site to be 11,000–15,000 females. Our results illustrate a dramatic recovery of the population, which is still increasing exponentially and shows no evidence of slowing, suggesting it has not reached 50% of its carrying capacity.
Main conclusions  We estimate that, since the 1970s, the Ascension Island population of green turtles has increased by 285% and question the recent listing of this species as endangered by the IUCN (World Conservation Union), in particular in the Atlantic Ocean, where 75% of the populations assessed by the IUCN are increasing. Indeed, we estimate the global population of this species to be in excess of 2.2 million individuals. We suggest that the IUCN's global listing process detracts attention from those populations that are truly threatened with extinction and should not, in its present form, be applied to globally distributed long-lived species such as marine turtles.     

Genetic divergence of three freshwater isopod species from southern New Zealand

Aim We examined the biogeography of three freshwater isopod species (Austridotea annectens, A. lacustris, A. benhami), and tested the hypotheses that genetic differences would: (1) exist between geographic locations; and (2) correspond to known geological events (e.g. appearance of islands leading to the availability of habitat). Location Southern New Zealand, including South Island, Stewart Island, Campbell Island and Chatham Islands. Methods We examined specimens throughout the known species range from 12 populations of A. lacustris, five populations of A. annectens, and three populations of A. benhami, using mitochondrial DNA (cytochrome c oxidase I) sequence analyses. Results We resolved three main clades corresponding to the three species, with 16% sequence divergence between A. annectens and A. benhami, and 31% divergence between these species and A. lacustris. Divergence within A. benhami was < 2.0%. However, divergence within A. lacustris reached up to 10% with four main groupings: (1) Chatham Islands; (2) Campbell Island; (3) Fiordland; and (4) east coast South Island and Stewart Island. Divergence within A. annectens reached up to 4.4%, with two main groupings: (1) Chatham Islands and (2) east coast South Island and Stewart Island. Patterns of genetic divergence were most likely the result of geographical isolation among A. lacustris and A. annectens populations. In particular, the divergence of A. lacustris and A. annectens on Chatham Islands may correspond to the availability of this habitat c. 4 Ma, whereas the divergence of A. lacustris on the much older Campbell Island and in Fiordland may indicate either a rare founder event or a change in ocean circulation that resulted in their isolation from a once more widespread gene pool. Main conclusions The three New Zealand species of Austridotea are genetically distinct, with up to 31% divergence between species. Genetic variability was highest between populations of the two most widely distributed species, and divergence was greatest on islands distant from mainland New Zealand and in the discrete Fiordland region. The magnitude of genetic divergence of isopods on the Auckland and Chatham Islands is consistent with these populations having been founded in the Pliocene via oceanic dispersal from mainland New Zealand.     

Biology of <Emphasis Type="Italic">Lasioglossum</Emphasis> (<Emphasis Type="Italic">L.</Emphasis>) <Emphasis Type="Italic">majus</Emphasis> (Hymenoptera: Halictidae), a largely solitary sweat bee with behavioural adaptations to communality

Within the bee family Halictidae there have been three origins of sociality. Although detection of origins and reversal from sociality requires phylogenetic studies, at a behavioural level a predisposition to sociality can be detected by analysis of intra-specific interactions. We studied aspects of nesting biology and behavioural interactions in Lasioglossum (Lasioglossum) majus, a poorly known halictine inhabiting temperate regions of Europe, which is suspected to be solitary. Nests were found to be largely used by one female, but some were shared by more than one individual. These few nests, whose entrances were very close to each other, were found to be connected underground. A few individuals were observed to enter in a nest where a female was waiting, behaving as a guard and allowing the incoming bee to enter the nest. By use of circle-tube experiments, the behavioural repertoire exhibited by females during encounters was assessed. Levels of withdrawal and cooperative events were comparable with those observed in other solitary nesting species, but aggressive events were very rare, as in several observed communal species. We conclude that L. (L.) majus females, despite general solitary nesting, possess behavioural components enabling them to adopt, probably in high nest-density areas, nest-sharing strategies. A similar kind of local social polymorphism has been observed in two other species of the subgenus Lasioglossum, but these are the first data available on a European species and the first record of subterranean connections among nests of halictid bees.     

Nest site selection in middle and great spotted woodpeckers <Emphasis Type="Italic">Dendrocopos medius</Emphasis> &; <Emphasis Type="Italic">D. major</Emphasis>: implications for forest management and conservation

Success of species conservation depends to a large extent on comprehensive management that considers all critical aspects of a species’ niche. Many studies have examined habitat factors in relation to occurrence, abundance or foraging behaviour of European woodpecker species, while relatively little is known about nest site selection. I compared habitat structures used for nesting by middle and great spotted woodpeckers Dendrocopos medius and D. major with available structures in an oak forest in the Swiss lowlands. I first tested if nest trees were randomly selected among available trees by focusing on species, condition and diameter of nest trees, and on the presence of the fruiting body (hereafter sporophore) of polypores (wood-decomposing fungi). Second, I examined if the nesting niches of the two species were differentiated. Both species showed strong preferences for oaks, large trees, dead trees and for trees with sporophores. Nest sites of the two species differed most strongly with respect to the presence of sporophores, cavity age and tree condition, pointing towards interspecific competition for nest sites. Old living or dead trees with sporophores are central components of the nesting niche of middle and great spotted woodpeckers. Conservation plans for the threatened middle spotted woodpecker have so far mostly focused on the needs in terms of distribution and foraging; future conservation strategies and forest management must take into account the preference for dead and decaying trees with sporophores as another vital resource. This will also provide benefits for other woodpecker species as well as for the community of secondary cavity nesters.     

Decline of the breeding population of <Emphasis Type="Italic">Pygoscelis antarctica</Emphasis> and <Emphasis Type="Italic">Pygoscelis adeliae</Emphasis> on Penguin Island,South Shetland,Antarctica

This work is a quantitative analysis of the population of breeding pairs of Pygoscelis adeliae and Pygoscelis antarctica, which use Penguin Island as a breeding area. There was a decrease in the populations of P. adeliae and P. antarctica by 75 and 66%, respectively, from the breeding season of 1979/1980 to 2003/2004. A mixed breeding colony of both species was also documented, according to published data which has existed since 1979/1980. The P. antarctica has an advantage over P. adeliae in this mixed breeding situation, where the breeding pairs of the former increased by 127%, indicating an interspecies competition for nesting ground.     

Population genetic connectivity of an endemic New Zealand passerine after large‐scale local extirpations: a model of re‐colonization potential

Little is known about how a 70% loss of native forests has affected the genetic connectivity of remnant bird populations in New Zealand. We use the common and widely distributed New Zealand Bellbird Anthornis melanura as an indicator species of population connectivity for well‐flighted birds. Using eight microsatellite loci, we identified five main genetic populations in the North Island, South Island, sub‐Antarctic Auckland Islands and two small remnant island populations adjacent to a large region of avian extirpations in northern North Island. Only one remnant island population, on a 30‐year‐old conservation reserve at Tiritiri Matangi, displayed a clear signature of recent genetic bottleneck. The 7% migration rate at Tiritiri Matangi indicates that bottlenecks can be maintained despite habitat rehabilitation, possibly through behavioural barriers to gene flow. Adjacent to the same extirpation zone, Bellbirds on the Poor Knights Islands were found to have low genetic diversity and low re‐colonization potential. Two gaps concordant with deforestation patterns separated the Kapiti Coast of southern North Island from populations to both the north and the south. In summary, we identified linked avian habitats, as well as isolated and inbred populations and suggest that Bellbirds are good re‐colonizers. We emphasize the importance of genetic studies that assess animal dispersal among newly rehabilitated habitat patches.     

Phylogeography of the New Zealand blue duck (<Emphasis Type="Italic">Hymenolaimus malacorhynchos</Emphasis>): implications for translocation and species recovery

Translocation of individuals among extant populations is an important tool in species conservation that allows managers to supplement dwindling populations and potentially alleviate the deleterious effects of inbreeding. Ideal translocation strategy should consider historical relationships among existing populations to avoid potential disruption of population subdivision and local adaptation. Here, we examine mitochondrial sequence variation in the endangered blue duck Hymenolaimus malacorhynchos, a New Zealand endemic riverine specialist, to facilitate informed decision making in future translocations. Behavioural observations suggest that blue duck dispersal is limited and may result in genetic structure within and between regional populations. We analysed 894 base pairs of mitochondrial control region in 78 adult blue ducks sampled from 11 river catchments across the species’ range (representing four regions in the North Island and three regions in the South Island) and found strong and significant genetic structure both within and among islands. These results, combined with a 2.0% sequence divergence between islands, indicates that North Island and South Island blue ducks should be treated as separate management units. The relationship between genetic differentiation and geographic distance for blue ducks on the South Island conformed to an “isolation by distance” pattern. Overall, we recommend that translocations of blue ducks should not be made between the North and the South Islands and those within each island should be restricted to neighbouring catchments.