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.     

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.     

Habitat use, diet and body size of Heard Island weevils

Habitat use, diet and body-size variation are examined in weevils from Heard Island, with specific attention being given to the Ectemnorhinus viridis species complex. E. viridis shows marked altitudinal variation in body size and vestiture, but there are no consistent associations between body size and diet, nor are there consistent among-individual differences in conventional taxonomic characters. Thus, the status of E. viridis as a single, variable species is maintained. This species occurs from sea level to 600 m and it feeds on vascular plants and bryophytes. Canonopsis sericeus also feeds on bryophytes and vascular plants and occurs over a narrower altitudinal range. Palirhoeus eatoni is restricted to the surpralittoral zone where it feeds on marine algae and lichens. Bothrometopus brevis and B. gracilipes both feed on cryptogams, with the former species occurring from sea level to 450 m, and the latter from 50 to 550 m above sea level. In all species, males are smaller than females and there is a size cline such that populations from higher elevations are smaller than those at lower altitudes. This cline is the reverse of that found on the Prince Edward Islands which, unlike Heard Island, lie to the north of the Antarctic Polar Frontal Zone. This difference in body-size clines between weevils on the two island groups is ascribed to the shorter growing season on the colder Heard Island. The information presented here supports previous ideas regarding the evolution of the Ectemnorhinus-group of weevils on the South Indian Ocean Province Islands, although it suggests that subsequent tests of these hypotheses would profit from the inclusion of molecular systematic work.     

Moss-inhabiting diatom communities from Heard Island,sub-Antarctic

In this paper, we list 192 diatom taxa, collected from bryophyte samples from Heard Island (52°05S, 73°30E). The Heard Island diatom flora shows a marked similarity to those of the Crozet and Kerguelen archipelagos, and is quite dissimilar to the moss-dwelling diatom flora of Macquarie and Amsterdam Island. Based on species composition, three main groups of samples could be discerned. Each group represents a different habitat. Samples dominated by Diadesmis ingeae, Pinnularia borealis and several Psammothidium species seem to prefer the driest habitats. A special form of this community was found in shaded areas. Samples from wet habitats such as flush areas and pools were dominated by species such as Adlafia bryophila, Sellaphora tumida, Fragilaria capucina and Planothidium lanceolatum. An intermediate group was observed in more acid, but terrestrial, conditions, characterised by Eunotia paludosa and Chamaepinnularia soehrensis var. muscicola. These community patterns are similar to those found on other sub-Antarctic islands, and we suggest that a group of typical sub-Antarctic species and communities exists.     

Genetic variability in the wingless subantarctic genus Anatalanta (Diptera, Sphaeroceridae): a preliminary approach

The first study on the genetic variability of a wingless subantarctic fly (Diptera: Sphaeroceridae) at Iles Crozet is presented. Flies of the genus Anatalanta live mainly in seabird colonies from the littoral level to 700 m a.s.l. Two species are known: A. aptera Eaton and A. crozetensis Enderlein. Several morphological forms from 2 islands have been surveyed and 21 enzyme systems, involving 30 common putative enzyme loci, were scored from reared individuals. Mean heterozygosity values vary from 0.053 to 0.169. Genetic differentiation is weak with low Nei's distances. Noticeable gaps between morphological and genetic data are emphasized and question the real taxonomic status of the two recognized species. It is now necessary to compare populations of the genus Anatalanta from its whole distributional range (Iles Crozet, Iles Kerguelen and Heard Island). An improved understanding of the historical processes by which these islands were colonized could result from these studies. Received: 12 August 1996 / Accepted: 30 June 1997     

Population status and breeding season chronology of Heard Island fur seals

Fur seals were eliminated by sealers at Heard Island soon after its discovery in the 1850s. The first recorded breeding of Antarctic fur seals (Arctocephalus gazella) since sealing was reported in early 1963 (two pups). The most recent survey of the Heard Island fur-seal population was undertaken between November 2000 and March 2001, when 1,012 Antarctic fur-seal pups were born. This represents a fourfold increase since the last complete census in 1987/1988 (13 years), when 248 births were recorded. Pup estimates and counts available for eight breeding seasons since 1962/1963 suggest the population has been increasing at between 12 and 20% per year. Based on pup production, the breeding population is estimated to number approximately 4,100 seals. The number of fur seals on Heard Island peaked in late February/early March at 29,256 indicating that, in addition to the breeding population, a significant number of seals born elsewhere haul out on the island. Most of these are moulting sub-adult and adult males. As in 1987/1988, only one subantarctic fur-seal pup (A. tropicalis) was observed, suggesting this species is not colonising the island, as has been speculated.     

Probable long distance dispersal of Leptinella plumosa Hook.f. to Heard Island: habitat, status and discussion of its arrival

During the 2003–2004 austral summer the number of vascular plant species recorded from Heard Island rose from 11 to 12 with the discovery of one small plant of Leptinella plumosa Hook.f. (Asteraceae), an indigenous subantarctic species. It is described and its habitat, likely status and possible means of arrival on the island are discussed. We conclude that the species probably arrived by natural means with a seabird as its most likely dispersal vector. The life history and biology of L. plumosa indicates its likely persistence on Heard Island.     

Consumption of marine resources by seabirds and seals at Heard Island and the McDonald Islands

Summary The seabird and seal community at Heard Island and the McDonald Islands comprised an estimated total biomass of 27893 tonnes of which the 15 breeding species of seabirds made up 70%. The total annual consumption of marine resources was estimated to be approximately 521 000 t, of which 81% was consumed by seabirds Approximately 165 000 t of fish, 41 600 t of squid and 312 000 t of crustaceans are consumed annually by this seabird and seal community. The annual energy flux to this community was estimated to be 2.17·10¹² kJ and approximately 56 000 t of carbon are consumed annually. Breeding populations of King Penguins and Antarctic Fur Seals are increasing, that of the Southern Elephant Seal is decreasing; there are no data on the population trend for Macaroni Penguins, the predominant consumer species. Commercial fisheries are presently operating at the nearby Iles Kerguelen, and similar activities may prove to be commercially viable at Heard Island. The fishery is for Champsocephalus gunnari, a major prey species of penguins and Antarctic Fur Seals at Heard Island during the summer breeding season.     

Ecology of Heard Island Diptera

Phenology, distribution and abundance of three Diptera species on Heard Island were investigated to provide baseline data for monitoring the effect on climate change on populations. Five vegetation types at two localities were sampled in two different years, firstly in the summer of 1987–1988 at Atlas Cove and secondly at Spit Bay over 12 months from summer 1992 to summer 1993. Pitfall traps and soil core extractions were operated in summer at both localities and pitfalls alone for 12 months from Spit Bay. The wingless Anatalanta aptera was the most abundant species in traps at Atlas Cove with most individuals collected from Poa tussock grassland, half as many from Pringlea and Azorella vegetation and fewest with a significantly higher level of asymmetry in the large katepisternal setae, from Azorella and Fellfield. Calycopteryx moseleyi was the most abundant fly in traps at Spit Bay, and A. maritima was the least abundant at both localities. Monthly pitfall catches from 1992–1993 indicated that A. aptera was active in most months of the year apart from winter, females early in the season and males active throughout the summer; teneral individuals only detected in January. C. moseleyi was more strongly seasonal with peak adult numbers occurring in January. Amalopteryx maritima was least seasonal in activity. Asymmetry in A. aptera suggests that it was at the limit of its ecological tolerance in Fellfield and Azorella on Heard Island. Changes caused by climate warming or invasive species are mooted.     

The African timber tree <Emphasis Type="Italic">Entandrophragma congoense</Emphasis> (Pierre ex De Wild.) A.Chev. is morphologically and genetically distinct from <Emphasis Type="Italic">Entandrophragma angolense</Emphasis> (Welw.) C.DC

Interpreting morphological variability in terms of species delimitation can be challenging. However, correcting species delineation can have strong implications for the sustainable management of exploited species. Up to now, species delimitation between two putative timber species from African forests, Entandrophragma congoense and E. angolense, remained unclear. To investigate their differences, we applied an integrated approach which combines morphological traits and genetic markers. We defined 13 morphological characters from 81 herbarium specimens and developed 15 new polymorphic microsatellite markers to genotype 305 samples (herbarium samples and specimens collected in the field across the species distribution ranges). Principal component analysis (PCA) of morphological data and the Bayesian clustering analyses of genetic data were used to assess differentiation between putative species. These analyses support two well-differentiated groups (F_ST?=?0.30) occurring locally in sympatry. Moreover, these two groups present distinct morphological characters at the level of the trunk, leaflets, and seeds. Our genetic markers identified few individuals (4%) that seem to be hybrids, though there is no evidence of genetic introgression from geographic patterns of genetic variation. Hence, our results provide clear support to recognize E. congoense as a species distinct from E. angolense, with a much lower genetic diversity than the latter, and that should be managed accordingly. This work highlights the power of microsatellite markers in resolving species boundaries.     

Preliminary assessment of population structure in the mackerel icefish (Champsocephalus gunnari)

The mackerel icefish (Champsocephalus gunnari Lönnberg E (1905) The Fishes of the Swedish South Polar Expedition. Wiss. Ergebnisse Schwedische Südpol- Exped. 1901–1903, vol 5, p 37 is widely distributed south of the Antarctic convergence and over shelf areas surrounding sub-Antarctic Islands. In order to evaluate global population structure in this species, we examined DNA sequence variation in four mitochondrial regions and four nuclear genes in icefish from four locations in the Atlantic Ocean sector and one location in the Indian Ocean. Despite small sample sizes, mitochondrial and nuclear gene data indicated the existence of at least three genetically distinct stocks: Heard Island, South Shetland Islands, and the remaining Atlantic populations (Shag Rocks, South Georgia, and Bouvet Island). The mitochondrial and nuclear SNP markers developed here will be useful for more extensive analyses of population structure in this 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.     

Weather to go out: activity of<Emphasis Type="Italic"> Bothrometopus brevis</Emphasis> (Curculionidae) at Heard Island

Despite the wealth of knowledge available on the ecology, biology and physiology of the Ectemnorhinus group of weevils, little is known about the determinants of their activity patterns. Here we investigated the relationship between the activity of Bothrometopus brevis (C.O. Waterhouse) and wind direction and strength, precipitation, cloud cover, temperature, relative humidity, and habitat moisture status, on Heard Island. B. brevis was most active during warm, north-wind and light rain conditions or when it was not raining, but its habitat was wet. During heavy precipitation, activity was low, and it was negligible during cold, south-wind conditions, especially during rain or snow. There was a clear relationship between activity and early frontal conditions, which also appears to be consistent across weevil species on Heard and Marion islands. The importance of frontal rain for activity suggests that any change to frontal movement across the islands might have pronounced impacts on weevil activity.     

POPULATION SIZE AND BREEDING SEASON OF THE ANTARCTIC FUR SEAL ARCTOCEPHALUS GAZELLA AT HEARD ISLAND—1987/88

Breeding colonies of the antarctic fur seal Arctocephalus gazella on Heard Island (53°10'S, 73°30'E) are situated on the sheltered northern and eastern coasts on flat vegetated terrain near streams and pools. Pupping in the 1987/88 summer began on 21 November, with 90% of births in 26 d. The median birth date was 11 December. Pup counts at Heard Island made in seven breeding seasons from 1962/63 to 1987/88 show an exponential rate of increase of 21%, which may be inflated due to undercounting in early years. The total of 248 births in 1987/88 represents an exponential increase of 37% since the previous year, but pups may have been undercounted then. Based on the number of pups born, the breeding population is estimated at 870–1,120. During the breeding season, the largest number of animals ashore was 835. Many non-breeding fur seals began hauling out from early January and 15,000 animals were estimated to be ashore by late February, a fat larger number than expected from the size of the breeding population. Both the breeding and non-breeding components of the population may be augmented by immigration. The source of immigrants may be undiscovered breeding colonies of this species in the northwestern sector of the Kerguelen Archipelago or the concentration at South Georgia. Further censuses are required at Heard Island to monitor the population growth.     

The influence of stream flow reduction on the energetics of endemic Hawaiian torrenticolous aquatic insects, <Emphasis Type="Italic">Telmatogeton</Emphasis> Schiner and <Emphasis Type="Italic">Procanace</Emphasis> Hendel

Tropical island stream ecosystems continue to be threatened by increasing anthropogenic demands for freshwater, with many streams dammed or diverted. Stream flow amendments can have substantial effects on aquatic insect populations of tropical archipelagoes. In Hawaiian streams, an endemic Diptera community of the following genera dominates cascades and other torrential habitats: Telmatogeton Schiner (Chironomidae), Procanace Hendel (Canacidae), Scatella Robineau-Desvoidy (Ephydridae). Larval densities, standing stock biomass (SSB, as ash-free dry mass [AFDM]), and monthly secondary production of Telmatogeton and Procanace were measured during two summers of significantly different stream discharge in Iao Valley, Maui, Hawaii. Very few Scatella larvae were collected (<20 larvae for both years combined), so they were omitted from subsequent analyses. Stream discharge decreased approximately 40% from 1994 to 1995, providing a ‘natural test’ of the effects of reduced stream flow on these torrenticolous populations between two years. Combined Telmatogeton and Procanace SSB (total torrential community SSB) was 3176 and 1683 mg AFDM m⁻² for 1994 and 1995, respectively, with Telmatogeton accounting for >95% in both years due to significantly larger body size and high density. The SSB of Telmatogeton significantly decreased from 3138 to 1622 mg AFDM m⁻² from 1994 to 1995 but increased for Procanace (37.6–60.9 mg AFDM m⁻², respectively). Total torrential community secondary production was 31% lower in 1994 (12,833 mg AFDM m⁻² mo⁻¹) compared to 1995 (8855 mg AFDM m⁻² mo⁻¹), reflecting the Telmatogeton proportion of total community production (99%); however, Procanace production increased by 40%. Monthly P/B ratios indicated that biomass turnover was generally high and increased for Telmatogeton from 1994 (3.8) to 1995 (5.1), whereas it remained lower and did not change between years for Procanace (1.7). A natural drought of the Iao Stream valley was associated with structural and functional changes in two endemic aquatic insects; these results are a conservative indication of permanent stream flow reductions from anthropogenic withdrawal (e.g., dams and diversions).     

Systematics,biogeography, and evolution of Pristurus minimus (Squamata,Sphaerodactylidae) with the discovery of the smallest Arabian vertebrate

Almost 20% of Oman’s terrestrial reptiles are found on Masirah Island. Despite its ancient geological history and its long isolation, Masirah Island only harbours one endemic reptile species, Hemidactylus masirahensis. In this study, we use an integrative approach to explore the variation in Pristurus minimus, to revise its systematics and to assess its phylogeography by using molecular (mitochondrial and nuclear DNA sequences) and morphological data. Our results uncovered a deep divergence within P. minimus that dates back to ～4?Ma, during the Pliocene Epoch. The old divergence separated P. minimus into two allopatric species: one from mainland Arabia, P. minimus, and one endemic to Masirah Island, described as a new species herein. Despite the general similarity between the two sister species, there are morphological differences related mainly to body size. The new Pristurus species endemic to Masirah Island is significantly smaller than its mainland sister taxon, becoming the smallest known vertebrate species in Arabia and one of the smallest lizard species in the world. The phylogenetic analyses also uncovered a low level of genetic diversity within the newly described Pristurus species endemic to Masirah Island and a relatively deep genetic divergence within P. minimus that dates back to the Pleistocene. Once more, the present study highlights the relatively high levels of reptile diversity and endemicity in south-eastern Arabia despite its harsh, arid climate and stresses its relevance from a conservation point of view.

The LSIDs for this publication is: urn:lsid:zoobank.org:pub:DB0658D5-7F68-4E66-885F-75E27F9CD512.     

Vegetation of the McDonald Islands, sub-Antarctic

The McDonald Islands (53°03^′S, 72°36^′E) are situated in the southern Indian Ocean, approximately 43 km west of Heard Island. These sub-Antarctic islands comprise McDonald Island itself, measuring ca.1 × 2 km, and two much smaller rocky outcrops, Flat Island and Meyer Rock. Five species of vascular plant occur on the islands. Only four species of moss were found, no hepatics, and eight species of lichen, together with algal and fungal species. Phanerogamic vegetation, comprising grassland and cushion-carpet herbfield, covers about one-third of the main island. Elsewhere, vegetation is absent or restricted to cryptogamic species. The distribution and occurrence of vegetation are strongly influenced by salt deposition, exposure to wind, substrate stability and biotic influences, particularly the very large assemblages of sea birds. The species-depauperate McDonald Islands are unique and have suffered negligible human impact. A management plan has been prepared; its implementation will be assisted by the information in this paper. The islands' protection will be further enhanced by an affirmative final decision on the current proposal for World Heritage Listing of Heard and the McDonald Islands. Received: 15 November 1996 / Accepted: 24 March 1997     

Notes on parasites in penguins (Spheniscidae) and petrels (Procellariidae) in the Antarctic and Sub-antarctic

Blood smears were examined from 143 penguins of four species (Aptenodytes patagonicus, Eudyptes chrysolophus, E. schlegeli, and Pygoscelis gentoo) from Sub-antarctic Macquarie Island and Heard Island. No blood parasites were reported. The vectors of Hepatozoon albatrossi (reported from three species of albatross) are probably shared by penguins, and it is suggested that the latter are not susceptible to infection with this protozoan. Cestodes of the genus Tetrabothrius were present in large numbers in the intestines of 17 Antarctic petrels (Thalassoica antarctica), and evidence is presented indicating that euphausiid crustaceans may be intermediate hosts.     

Seasonal change in foraging areas and dive depths of breeding king penguins at Heard Island

The seasonal variation in the foraging behaviour of king penguins (Aptenodytes patagonicus) was studied at Heard Island (53°05′S, 73°30′E) during 1992/1993. On seven occasions throughout the breeding cycle, time-depth-light recorders were deployed on breeding adults to record the dive activities and foraging. Foraging locations changed with season: in autumn and spring 1992, adults foraged between 48–52°S and 74–78°E, about 370 km NNE of Heard Island close to the Polar Front. Two penguins tracked in winter travelled 2220 km east of Heard Island (95°E) along the northern ice limit, and 1220 km south of Heard Island to approximately 65°S, respectively. In spring (October), the penguins again foraged further north than during winter. The foraging area utilised in October overlapped the area where the penguins foraged in March/April. The penguins' diving behaviour also varied seasonally: the modal depth of deep dives (>50 m) increased from about 100 m in February to 220 m in October. Mean dive depths increased from 70 ± 52 m in March 1992 to 160 ± 68 m in August 1992. Penguins dived deep (>50 m) only during daylight hours (16 h in February, 9 h in July). Mean dive durations ranged from 2.9 ± 1.1 min in March 1992 to 5.1 ± 1.2 min in August 1992. Associated with changes in foraging location and dive behaviour was a change in diet composition: during summer the penguins ingested mainly myctophid fish (>90%) while in winter the most important diet item was squid. Accepted: 19 October 1998