The first record of a terrestrial landhopper (Crustacea: Amphipoda: Talitridae) from Macquarie Island

A terrestrial talitrid crustacean is recorded for the first time from subantarctic Macquarie Island. The species, Puhuruhuru patersoni, is native to the southern part of the South Island of New Zealand. Its distribution on Macquarie Is. is restricted to a single locality near the ANARE station on the Isthmus. All mature females collected in December were carrying eggs; females appeared to be less mobile than males. It seems likely that the species has been transported accidentally from New Zealand, perhaps by the same means that introduced the isopod, Styloniscus otakensis, also from southern New Zealand.     

Comparison of foraging strategies of incubating king penguins Aptenodytes patagonicus from Macquarie and Heard islands

The foraging strategies of king penguins from Heard and Macquarie islands were compared using satellite telemetry, time-depth recorders and diet samples. Trip durations were 16.8±3.6 days and 14.8±4.1 days at Macquarie and Heard islands, respectively. At Macquarie Island, total distances travelled were 1281±203 km compared to 1425±516 km at Heard Island. The total time the penguins spent at sea was 393±66 h at Macquarie Island and 369±108 h at Heard Island. The penguins from Macquarie Island performed more deep dives than those from Heard Island. King penguins from Macquarie Island travelled 1.5±0.2 km h⁻¹ day⁻¹ compared to 1.3±0.1 km h⁻¹ day⁻¹. At Macquarie Island, 19% of dives were upto 70–90 m depth compared to 35% at Heard Island. The main dietary prey species were the fish Krefftychthis anderssoni and the squid Moroteuthis ingens in both groups. The differences in the at-sea distribution and the foraging behaviour of the two groups of penguins were possibly related to differences in oceanography and bathymetric conditions around the two islands. Dietary differences may be due to interannual variability in prey availability since the two colonies were studied during incubation but in different years.     

Inferring origins of migrating insects using isoscapes: a case study using the true armyworm,Mythimna unipuncta,in North America

1. Many important insect pests undertake seasonal migrations at continental scales in response to changes in resource quality and availability. The frequency and timing of these events could be influenced by the impact of climate change on the suitability of the different sites exploited throughout the year, yet, in many cases, little is known about the origin of seasonal populations, as tracking insect movements is extremely challenging due to their small body size. 2. The use of stable isotope measurements in insect tissues combined with the development of tissue‐specific ‘isoscapes’ of modelled geographic isotope patterns presents a potentially valuable but rarely used approach for obtaining such information on important pest species. In this paper it is illustrated how stable hydrogen isotope analyses (δ²H) in wing chitin of the true armyworm (Mythimna (Psuedaletia) unipuncta Haworth), a seasonal migrant, clearly delineated between 2016 spring immigrants and later locally produced moths in southern Ontario, Canada. 3. It is shown that adult moths captured in early fall in Texas were immigrants from farther north, the first direct confirmation of a southward return migration of this species. Stable carbon isotope (δ¹³C) measurements indicated that spring immigrants in Ontario and autumn immigrants in Texas were from exclusively C3 biomes. Stable nitrogen isotope (δ¹⁵N) measurements also provided information on the probability of individuals coming from agriculturally intensive (i.e. higher δ¹⁵N) sites. Finally, several recommendations are provided regarding future research that could improve the Bayesian assignment models and thus improve assignment accuracy.     

Migration sources and pathways of the pest species Sogatella furcifera in Yunnan,China, and across the border inferred from DNA and wind analyses

The migration sources and pathways of Sogatella furcifera (Horváth) in topologically complex regions like Yunnan, China, and adjacent montane areas have long been a challenging task and a bottleneck in effective pest forecast and control. The present research reinvestigated this issue using a combination of mtDNA and long‐term historical wind field data in an attempt to provide new insights. Genetic analyses showed that the 60 populations of S. furcufera collected across Myanmar, Thailand, Laos, Vietnam, Yunnan, Guizhou, and Sichuan lack genetic structure and geographic isolation, while spatial analysis of haplotype and diversity indices discovered geographic relevance between populations. Migration rate analysis combined with high‐resolution 10‐year wind field analysis detected the following migration sources, pathways, and impacted areas which could explain the outbreak pattern in Yunnan. (a) Dominating stepwise northward migrations originated from northern Indochina, southern Yunnan, and central‐eastern Yunnan, impacting their northern areas. (b) Concurring summer–autumn southward (return) migration originated from nearly all latitude belts of Sichuan and Yunnan mainly impacting central and southern Yunnan. (c) Regular eastward and summer–autumn westward migrations across Yunnan. The northward migration reflects the temporal rhythm of gradual outbreaks from the south to the north in a year, while the return migration may explain the repeated or very severe outbreaks in the impacted areas. To form a better pest forecast and control network, attention must also be paid to the northern part of Yunnan to suppress the impact of return migration in summers and autumns.     

Effects of temperature on growth rates of fungi from subantarctic Macquarie Island and Casey,Antarctica

Summary The linear growth rates of fungal isolates were measured on agar plates at temperatures ranging from 4° to 35°C. Fungi tested included the major fungal colonizers of leaves and litter of the three dominant plant species on subantarctic Macquarie Island, and major fungal species associated with plant and soil communities near Australia's Casey Station on the Antarctic Continent. All fungi grew at 4°C and were classified as psychrotrophs. Maximum growth rates were recorded at temperatures of 10° to 20°C for 13 of the 15 isolates from Macquarie Island and for all six isolates from Casey. Most of the leaf colonizing fungi from Macquarie Island had optimum growth temperatures of 15°C whereas all litter fungi from Macquarie Island and Casey fungi except Thelebolus microsporus had optimum growth temperatures of 20°C or above. Maximum growth of all species was at temperatures above those normally prevailing in their natural environments, with most species growing at 4°C at between 10% and 30% of their maximum rates. However, microclimatic effects may have resulted at times in temperatures near their growth optima. The highest growth rates at 4°C were recorded for Phoma spp. 1 and 2, Phoma exigua and Mortierella gamsii from Macquarie Island and Mortierella sp. 1 from Casey. Thelebolus microsporus and sterile sp. G from Casey also grew relatively fast at 4°C, and these species, and Phoma sp. 3 and Phoma exigua from Macquarie Island had the lowest Q-₁₀ values for the temperature range 4° to 15°C.     

Decadal shifts in autumn migration timing by Pacific Arctic beluga whales are related to delayed annual sea ice formation

Migrations are often influenced by seasonal environmental gradients that are increasingly being altered by climate change. The consequences of rapid changes in Arctic sea ice have the potential to affect migrations of a number of marine species whose timing is temporally matched to seasonal sea ice cover. This topic has not been investigated for Pacific Arctic beluga whales (Delphinapterus leucas) that follow matrilineally maintained autumn migrations in the waters around Alaska and Russia. For the sympatric Eastern Chukchi Sea (‘Chukchi’) and Eastern Beaufort Sea (‘Beaufort’) beluga populations, we examined changes in autumn migration timing as related to delayed regional sea ice freeze‐up since the 1990s, using two independent data sources (satellite telemetry data and passive acoustics) for both populations. We compared dates of migration between ‘early’ (1993–2002) and ‘late’ (2004–2012) tagging periods. During the late tagging period, Chukchi belugas had significantly delayed migrations (by 2 to >4 weeks, depending on location) from the Beaufort and Chukchi seas. Spatial analyses also revealed that departure from Beaufort Sea foraging regions by Chukchi whales was postponed in the late period. Chukchi beluga autumn migration timing occurred significantly later as regional sea ice freeze‐up timing became later in the Beaufort, Chukchi, and Bering seas. In contrast, Beaufort belugas did not shift migration timing between periods, nor was migration timing related to freeze‐up timing, other than for southward migration at the Bering Strait. Passive acoustic data from 2008 to 2014 provided independent and supplementary support for delayed migration from the Beaufort Sea (4 day yr^?1) by Chukchi belugas. Here, we report the first phenological study examining beluga whale migrations within the context of their rapidly transforming Pacific Arctic ecosystem, suggesting flexible responses that may enable their persistence yet also complicate predictions of how belugas may fare in the future.     

Invasion of two exotic terrestrial flatworms to subantarctic Macquarie Island

Invasive species are a serious threat to biodiversity worldwide. The relatively simple ecological systems of the subantarctic have the potential to be significantly damaged by predatory species that invade. Two species of exotic, predatory, terrestrial flatworms were first collected in 1997 from two localities only 2 km apart, in the southeast of subantarctic Macquarie Island. The species were later identified as Kontikia andersoni and Arthurdendyus vegrandis. We report here the results of fieldwork in 2004 that established that both species now occupy about a seventh of the southeast of the island which has a total area of only 170 km² and that there seem to be no barriers to further expansion. The island was first discovered in 1810 and so it is likely the species were introduced by means of human intervention within the last 200 years. We provide evidence to show that both species originated in New Zealand and have probably been on the island for ∼100 years giving an average rate of spread of about 10 m per year. Other species of Arthurdendyus have been introduced from New Zealand to the United Kingdom where they prey on earthworms. The quarantine significance of A. vegrandis for Australia is discussed and recommendations made to reduce the probability of it entering Tasmania where it has the potential to become an agricultural pest.     

Fur seals at Macquarie Island: post-sealing colonisation,trends in abundance and hybridisation of three species

Commercial sealers exterminated the original fur seal population at Macquarie Island in the early 1800s. The first breeding record since the sealing era was not reported until March 1955. Three species of fur seal now occur at Macquarie Island, the Antarctic (Arctocephalus gazella), subantarctic (A. tropicalis) and New Zealand (A. forsteri) fur seal. Census data from 54 breeding seasons in the period 1954–2007 were used to estimate population status and growth for each species. Between the 1950s and 1970s, annual increases in pup production for the species aggregate were low. Between 1986 and 2007, pup production of Antarctic fur seals increased by about 8.8% per year and subantarctic fur seals by 6.8% per year. The New Zealand fur seal, although the most numerous fur seal species on Macquarie Island, has yet to establish a breeding population, due to the absence of reproductively mature females. Hybridisation among species is significant, but appears to be declining. The slow establishment and growth of fur seal populations on Macquarie Island appears to have been affected by its distance from major population centres and hence low immigration rates, asynchronous colonisation times of males and females of each species, and extensive hybridisation.     

Isotope evidence for latitudinal migrations of the dragonfly Sympetrum fonscolombii (Odonata: Libellulidae) in Middle Asia

• Sympetrum fonscolombii dragonflies are believed to migrate seasonally. In the spring and early summer, the already-mature dragonflies arrive in Middle Asia for reproduction. In the late summer and autumn, summer-generation dragonflies migrate to the south. Their wintering places remain unknown.
• Stable hydrogen (δ²H) and oxygen (δ¹⁸O) isotope analyses were conducted to confirm the migration of S. fonscolombii and determine the wintering area. Stable isotope composition of carbon (δ¹³C) and nitrogen (δ¹⁵N) in wings and legs was used to clarify the habitats in which dragonfly development took place.
• Three cohorts of dragonflies collected in different regions of Middle Asia were used for analysis: (i) immigrants that arrived in the spring, (ii) residents that developed in Middle Asia, and (iii) transit dragonflies migrating to the south during autumn.
• The average δ²H values in the wings were significantly higher in immigrants (−96‰) than in residents (−134‰) and transit individuals (−124‰). High δ¹⁸O and δ¹⁵N values in the tissue of immigrants confirmed their southerly origin.
• Based on the species range and the global distribution of annual averages of δ²H and δ¹⁸O values in precipitation, the latitudinal migrations of S. fonscolombii were inferred to cover the area from the proposed natal regions of immigrants in South-West Asia (below ∼36°N) to Southern Ural and the south of Western Siberia in the north (54–55°N) with a maximum migration distance of more than 4000 km.

     

The impact of introduced ship rats (Rattus rattus) on seedling recruitment and distribution of a subantarctic megaherb (Pleurophyllum hookeri)

Abstract The impact of introduced ship rats (Rattus rattus) on recruitment of the megaherb Pleurophyllum hookeri Buchan. (Asteraceae) was examined on subantarctic Macquarie Island, an island with no extant native terrestrial vertebrates. Pleurophyllum hookeri (Asteraceae) forms a dominant component of the Macquarie Island vegetation and is restricted to the subantarctic. The Macquarie Island population of P. hookeri is the most extensive and intact. Introduced ship rats (Rattus rattus) are well established in tall tussock grassland of Macquarie Island. We detected rat activity for the first time within P. hookeri herbfields, in autumn 2000. We found rats were destroying up to 90% of racemes. By excluding rats from caches of inflorescences that they had formed, we found they were having a significant negative effect on initial recruitment and seedling survival within the caches. However, because of high seedling mortality after 1 year, there was no sustained impact of the exclosures on P. hookeri seedling density.     

A long-term study of population characteristics and downstream migrations of the European eel Anguilla anguilla (L.) and the effects of a migration barrier in the Girnock Burn, north-east Scotland

Downstream migrations and population characteristics of eels Anguilla anguilla were studied between 1967–1982 and 2002–2005 using a fish trap and electrofishing in the Girnock Burn, a small oligotrophic upland sub‐catchment of the River Dee, north‐east Scotland, 70 km from the tidal limit. In limited mark‐recapture studies, 9% of eels were recaptured up to three times and 97% of all recaptures were made at the same electrofishing site. The recaptured eels had a low mean growth rate of c. 13 mm year⁻¹. Smaller eels appeared to show preferences for shallower habitats with small boulder and gravel–sand substrata. Trap catches exhibited seasonal modes in total length at 140–180 mm in late spring, and 320–340 mm in early autumn, probably relating to water temperatures and discharges. From other studies, it is inferred that the spring mode comprised sexually undifferentiated nomadic eels and the autumn mode differentiated males beginning their spawning migration. Large female eels were rare. The fish trap appears to have formed a major barrier to upstream migration since its construction in 1966. In‐stream density has decreased significantly since then from 16 to three eels 100 m⁻², biomass from 260 to 78 g 100 m⁻² and emigrants from 700 to 100 individuals year⁻¹. Emigrants have comprised c. 5% of the standing stock year⁻¹ since the 1970s. The proportion of larger differentiated eels in the Girnock Burn has, however, remained relatively constant and escapement has been c. 100–200 (probably male) eels year⁻¹ since the late 1960s. Evidence, including that from other northerly British rivers, is reviewed to assess the possible impacts of Europe‐wide declines in glass eel recruitment since the 1980s. It is recommended that the data series be maintained, plus further sex determination and ageing studies. Installation of an upstream trap to capture immigrants and studies of recolonization are proposed.     

Crossing the Tasman Sea: Inferring the introduction history of Litoria aurea and Litoria raniformis (Anura: Hylidae) from Australia into New Zealand

Abstract The amphibian fauna of New Zealand consists of three native species (Leiopelma spp.), and three Litoria species introduced from Australia in the last 140 years. We conducted a molecular phylogeographical study that aimed to identify the Australian origins of two species, Litoria aurea and Litoria raniformis. We used partial sequences of the mitochondrial cytochrome oxidase I (cox1) gene from 59 specimens sampled from across the range of both species to identify the probable source populations for the New Zealand introductions, and to describe the current genetic diversity among New Zealand Litoria populations. Our genetic data suggest that L. aurea was introduced into the North Island of New Zealand from two regions in Australia, once from the northern part of coastal New South Wales and once from the southern part of coastal New South Wales. Our data indicate that L. raniformis introductions originated from the Melbourne region of southern Victoria and once established in the South Island of New Zealand, the species subsequently spread throughout both islands. In addition, we found a distinct haplotype in L. raniformis from Tasmania that strongly suggests, contrary to earlier reports, that this species was not introduced into New Zealand from Tasmania. Finally, we identified two very distinctive mitochondrial lineages of L. raniformis within the mainland Australia distribution, which may be previously unrecognized species.     

Barging in: A Temperate Marine Community Travels to the Subantarctic

A diverse fouling community discovered encrusting a barge intended for deployment at subantarctic Macquarie Island is described and its role as a transport vector for non-indigenous marine organisms is discussed. The barge proved to be a potential vector capable of transporting entire epi-bethic communities, 20 species in total, from a temperate estuarine system (Derwent River, Tasmania, Australia) into the subantarctic. For one invasive amphipod species Monocorophium acherusicum, over 136000 individuals including ovigerous females were calculated to be associated with the barge fouling community. Although distinct differences exist between the thermal ranges of Macquarie Island and the Bruny bioregion of Tasmania, a hazard assessment based on the Gower similarity coefficient suggested sufficient similarity between the two environments to allow for survival of transported organisms for eight months of the year. Several invasive species are able to survive the thermal conditions of the subantarctic irrespective of the time of year. This study identifies the need for effective quarantine measures aimed at identifying and managing marine biosecurity hazards in association with human activities in high latitude regions.     

Biology and molecular phylogenetics of Nematoceras sulcatum, a second endemic orchid species from subantarctic Macquarie Island

A second orchid species, Nematoceras sulcatum M.A.Clem. et D.L.Jones, has been found on subantarctic Macquarie Island. A history of its discovery and recognition is provided. The morphology, biology and ecology of the new species are compared with N. dienemum (D.L.Jones) D.L.Jones, M.A.Clem. et Molloy, the other species of orchid on Macquarie Island. Molecular studies based on the internal transcribed spacer (ITS) region of nuclear ribosomal DNA reveal the phylogenetic relationship of the two Macquarie Island species compared to others in the genus from New Zealand and its Southern Ocean islands.     

Snow goose migration phenology is related to extratropical storm climate

The phenologies of autumn and spring migrations by greater snow geese (Anser caerulescens atlantica) are shown to be statistically independent. Spring and fall migration phenologies are demonstrated to be significantly related to synoptic scale atmospheric circulation systems (extratropical storms) rather than a factor such as temperature. Interannual variation in the timing of migratory movements by snow geese reflect interannual variation in the climatology of extratropical storms. Early fall migration is significantly related to an increased frequency of cyclonic disturbances off the United States east and gulf coasts. Years in which autumn migration is delayed occur when the Atlantic coast storm track is displaced northward. Late spring migrations are related to extratropical storms being more frequent over the Great Plains, along the gulf coast, and over the northern Gulf of Mexico. Increased cyclone activity through the Ohio River valley and over the Great Lakes tends to advance the onset of spring migrations.     

Variable shifts in spring and autumn migration phenology in North American songbirds associated with climate change

Monitoring studies find that the timing of spring bird migration has advanced in recent decades, especially in Europe. Results for autumn migration have been mixed. Using data from Powdermill Nature Reserve, a banding station in western Pennsylvania, USA, we report an analysis of migratory timing in 78 songbird species from 1961 to 2006. Spring migration became significantly earlier over the 46-year period, and autumn migration showed no overall change. There was much variation among species in phenological change, especially in autumn. Change in timing was unrelated to summer range (local vs. northern breeders) or the number of broods per year, but autumn migration became earlier in neotropical migrants and later in short-distance migrants. The migratory period for many species lengthened because late phases of migration remained unchanged or grew later as early phases became earlier. There was a negative correlation between spring and autumn in long-term change, and this caused dramatic adjustments in the amount of time between migrations: the intermigratory periods of 10 species increased or decreased by > 15 days. Year-to-year changes in timing were correlated with local temperature (detrended) and, in autumn, with a regional climate index (detrended North Atlantic Oscillation). These results illustrate a complex and dynamic annual cycle in songbirds, with responses to climate change differing among species and migration seasons.     

COMPARISON OF THE STOMACH CONTENTS OF SOUTHERN ELEPHANT SEALS, MIROUNGA LEONINA, AT MACQUARIE AND HEARD ISLANDS

Abstract: There are three major breeding populations of southern elephant seals centered on Macquarie Island, Kerguelen-Heard Islands and South Georgia-Antarctic Peninsula. The composition of the diet differs between these populations based on published data from Signy Island and data presented here from Macquarie and Heard Islands. These differences in diet appear to be linked to the location at which seals were sampled ranging from the least Antarctic (Macquarie Island) to the most Antarctic (Signy Island). The major food remains consisted of cephalopod beaks and fish eye lenses. More benthic material was found at Heard Island than at Macquarie Island. The diet at Macquarie Island differed between summer and winter and between young animals and adults. The difficulty in collecting dietary samples of southern elephant seals near their main foraging areas makes the study of the feeding ecology of this species extremely difficult in comparison with other Southern Ocean species.     

Seasonal movements of Gyrfalcons Falco rusticolus include extensive periods at sea

Little information exists on the movements of Gyrfalcons Falco rusticolus outside the breeding season, particularly amongst High Arctic populations, with almost all current knowledge based on Low Arctic populations. This study is the first to provide data on summer and winter ranges and migration distances. We highlight a behaviour previously unknown in Gyrfalcons, in which birds winter on sea ice far from land. During 2000–2004, data were collected from 48 Gyrfalcons tagged with satellite transmitters in three parts of Greenland: Thule (northwest), Kangerlussuaq (central‐west) and Scoresbysund (central‐east). Breeding home‐range size for seven adult females varied from 140 to 1197 km² and was 489 and 503 km² for two adult males. Complete outward migrations from breeding to wintering areas were recorded for three individuals: an adult male which travelled 3137 km over a 38‐day period (83 km/day) from northern Ellesmere Island to southern Greenland, an adult female which travelled 4234 km from Thule to southern Greenland (via eastern Canada) over an 83‐day period (51 km/day), and an adult female which travelled 391 km from Kangerlussuaq to southern Greenland over a 13‐day period (30 km/day). Significant differences were found in winter home‐range size between Falcons tagged on the west coast (383–6657 km²) and east coast (26 810–63 647 km²). Several Falcons had no obvious winter home‐ranges and travelled continually during the non‐breeding period, at times spending up to 40 consecutive days at sea, presumably resting on icebergs and feeding on seabirds. During the winter, one juvenile female travelled over 4548 km over an approximately 200‐day period, spending over half that time over the ocean between Greenland and Iceland. These are some of the largest winter home‐ranges ever documented in raptors and provide the first documentation of the long‐term use of pelagic habitats by any falcon. In general, return migrations were faster than outward ones. This study highlights the importance of sea ice and fjord regions in southwest Greenland as winter habitat for Gyrfalcons, and provides the first detailed insights into the complex and highly variable movement patterns of the species.     

Restricted plant species on sub-Antarctic Macquarie and Heard Islands

The recent distributional history of two Macquarie Island vascular plant species, Carex trifida, Poa litorosa, and the Heard Island vascular plant, Ranunculus crassipes is examined. C. trifida is known from only one small population on the north west coast of Macquarie Island. Four populations of P. litorosa were first recorded in the 1980s; we believe however, that it was first observed, but misidentified in the 1950s. R. crassipes was first discovered on Heard Island in the late 1980s. We argue that all three species are indigenous and arrived on their respective islands within the last 200 years by natural processes, most likely from warmer neighbouring islands, where these species have more extensive distributions. There have been small-scale changes in distribution of all species, mainly expansion. Further expansion of all three species is expected as a response to warming climate. Feral rabbit grazing is having a confounding negative influence on populations of P. litorosa.     

Distribution of cephalopods in the upper epipelagic northwestern Bering Sea in autumn

In the northwestern Bering Sea in autumn, the epipelagic cephalopod community was represented by the boreal fauna, and was found to be composed of three families and nine species of the order Teuthida: Gonatidae (Berryteuthis magister, Boreoteuthis borealis, Gonatopsis japonicus, Gonatus madokai, Gonatus kamtschaticus, Gonatus onyx, and Gonatus pyros), Chiroteuthidae (Chiroteuthis calyx) and Onychoteuthidae (Onychoteuthis borealijaponica). Two pelagic gonatid species (B. borealis and G. kamtschaticus) dominated the cephalopod community in the upper 50 m. The distribution patterns of B. borealis and G. onyx were associated with diel vertical migrations of these squid. The distribution of two distinct size groups of G. kamtschaticus suggested ontogenetic migration of larger squid to deeper layers, and adds to previous data suggesting that this species may be a heterogeneous assemblage. Demersal B. magister rarely occurred in the surface waters. The occurrence of maturing O. borealijaponica in the southern marine area indicated that these were occasional seasonal migrants from the ocean. The occurrence of juvenile C. calyx suggested that these squid may conduct vertical forage migrations from deep waters to the surface layers.