Microsatellite differentiation between Phillip Island and mainland Australian populations of the red fox Vulpes vulpes

Predation by the red fox Vulpes vulpes is believed to be threatening the little penguin Eudyptula minor on Phillip Island in Victoria. Polymorphism at seven microsatellite loci was examined to estimate the extent of differentiation between Phillip Island and mainland populations of V. vulpes. Loss of alleles has occurred on Phillip Island where foxes first appeared = 88 years ago compared with mainland populations. Genetic differentiation between the Phillip Island and mainland populations was high. The relatively high differentiation found between the two populations could be due to either low migration rates, the effect of the composition of founder animals or both effects. Further ecological and historical information about the populations is needed to explore the likely significance of these effects.     

中澳之间迁徙■鹬类和燕鸥类的环志介绍

From Australia to Asia (China)，the main species of the migratory bird are the waders and terns. In Oct. 1999，an invitation was extended by Dr. Clive Minton of the chairman of the Victorian Wader Study Group (VWSG) to catch and band waders and terns at Sandy Point，Swan Bay，Swan Island，Anderson Inlet/Inverloch，Phillip Island，Mud Islands，Geelong and Werribee and so on. The paper summarizes the methods (catch，bio-metric data，banding，recoveries，flagging，satellite tracking，data analysis on computer，fox control et al.)and results (species of wader and tern，number of banding from 1975 to 1999，calculate the minimum age，breeding success，age of first breeding，levels of fat deposits，molt，the distance of moved) and discuss. The total 141 787 waders，about 35 species (from 1975 to 1999) and 6 057 chicks and adults of terns，about 7-9 species (1998-1999) were captured and banded by the Victorian Wader Study Group.     

Recent invasion of European red foxes (Vulpes vulpes) on to Fraser Island (K'gari) and South Stradbroke Island

Invasive predators are globally significant drivers of threatened fauna population decline and extinction, and the early detection of new incursions is critical to the chances of successful predator eradication and fauna conservation. Here, we provide evidence of the recent invasion of European red foxes (Vulpes vulpes) on to two large and internationally significant islands off the southeast coast of Queensland, Australia – Fraser Island (K'gari) and South Stradbroke Island. From camera trap footage collected on Fraser Island since 2009, foxes have now been observed on seven different occasions between 2012 and 2016. Two scats collected on South Stradbroke Island in 2013 and 2014 tested positive for fox DNA (and negative for Canis spp. DNA), with fox presence confirmed by subsequent camera trap footage in 2016. These data confirm the recent incursion of foxes on to these islands and suggest that small populations now exist there. Fraser Island and South Stradbroke Island represent key RAMSAR wetland areas of refuge for populations of multiple threatened fauna that have never been previously been exposed to foxes. Fox impacts on these fauna can only be expected to increase without management intervention to eradicate them before they become widespread.     

Bird species diversity and abundance before and after eradication of possums and wallabies on Rangitoto Island, Hauraki Gulf, New Zealand

Five-minute bird counts were made on Rangitoto Island in 1998 and 1999, 8 and 9 years after the start, and 1 and 2 years after the completion of a 7-year programme that resulted in eradication of the introduced brushtail possum (Trichosurus vulpecula) and brushtailed rock wallaby (Petrogale penicillata). These were compared with counts made in 1990 (immediately before the start of the programme), to assess whether bird species diversity and abundance had increased as a result of the eradications. The number of bird species detected in 1998/99 was similar to 1990. Five-minute counts of all species except silvereye (Zosterops lateralis) and tui (Prosthemadera novaeseelandiae) were also similar in 1998/99 to those in 1990. Silvereye and tui counts increased significantly. This is most likely a response to increased flowering of pohutukawa (Metrosideros excelsa) and rewarewa (Knightia excelsa) as a result of possum (and wallaby) eradication. The most likely reason for no apparent increase in the abundance of other bird species is the continued presence of predators, especially ship rats (Rattus rattus), cats (Felis catus), and stoats (Mustela erminea).     

Spatial and temporal variation in the seroprevalence of canine heartworm antigen in the island fox

Island foxes (Urocyon littoralis) are endemic to six of the eight California Channel Islands (USA). The island fox is classified as a threatened species by the State of California, and recently three of the six subspecies have experienced abrupt population declines. As part of a continuing effort to determine the cause of the declines, we tested island fox serum samples collected in 1988 (n = 176) and 1997-98 (n = 156) over the entire geographic range of the species for seroprevalence of canine heartworm (Dirofilaria immitis) antigen. Using a commercially available enzyme-linked immunosorbent assay (PetChek, Idexx Laboratories, Westbrook, Maine, USA) we detected heartworm antigen in four of the six populations of island foxes. On San Miguel and Santa Rosa Islands, seroprevalence in adult foxes was >85% (n = 62) in 1988 and increased to 100% (n = 24) in 1997-98. On Santa Cruz Island, seroprevalence in adult foxes decreased from 83% (n = 30) to 58% (n = 26), whereas on San Nicolas Island, seroprevalence increased from 25% (n = 32) to 77% (n = 30) during the same period. All of the pups assayed (n = 33) were seronegative. The seroprevalences of heartworm reported herein for the four populations of island foxes are the highest yet reported for a fox species. However, additional demographic data reported elsewhere suggests that heartworm has not been a major factor in the recent declines of island fox populations.     

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.     

Ecological rebound on Phillip Island, South Pacific

Summary  Pigs released on Phillip Island (half-way between Sydney, Australia and Fiji) in 1793 were followed by goats and rabbits by 1830, quickly destroying the sub-tropical vegetation and the soil. By 1856, the island was described as mostly bare red ground with little remnant vegetation. The pigs and goats had gone by about 1900 but rabbits prevented most plant establishment. An experimental programme begun in 1979 to investigate the effect of the rabbits and the island's potential for regeneration quickly provided spectacular evidence. An eradication programme followed, initially using a highly virulent strain of myxoma virus which was very effective but resupply failed. Poisoning with 1080 supplemented by shooting, trapping and gassing finally achieved effective eradication in March 1986, with the removal of the last single rabbit in 1988. Regeneration by native and weed species has been spectacular with consequent faunal changes. Some changes present policy challenges.     

Comparisons of habitat structure and plant,arthropod and bird diversity between mainland and island sites near Perth,Western Australia

Detailed estimations of habitat structure, plant species diversity and diversity of arthropods were made at six 4.0 ha sites, two on mainland Western Australia near Perth and four on adjacent islands. The number of resident passerine bird species was also recorded at each site. Plant species diversity, and horizontal foliage diversity (=patchiness) varied only slightly between sites. There were significant positive correlations between arthropod Order diversity and bird diversity, and between vertical foliage diversity and bird diversity. In both Acacia and dune scrub, the Rottnest Island sites had more individuals of arthropods than the mainland sites but these belonged to fewer Orders. Numerical imbalance between arthropod Orders on Rottnest Island probably results from diminution of predators (passerine birds) there. As the actual number of arthropods is higher on the islands, the absence of so many species of passerine birds may result from other factors (ecological and historical).     

Measuring Recruitment in an Invasive Species to Determine Eradication Potential

ABSTRACT Optimal management of invasive pests can benefit from quantitative measures of rates of recruitment, and particularly, relative contributions of immigration and reproduction. However, these vital rates are difficult to estimate by trapping or observation. Recent studies have demonstrated that analyses with DNA markers may provide detailed information on the origin of immigrants into pest populations, but these studies have not provided comparable data on reproductive rates. We integrated genetic and demographic information from a unique longitudinal data set to comprehensively quantify recruitment during the past 15 years into an island population of red foxes (Vulpes vulpes) and to reveal relative contributions of immigration and reproduction. This population established 100 years ago and persists despite several decades of management aimed at population suppression. Primary source of recruits on the island was in situ reproduction (>95%/annum), although the number of foxes reproducing was small relative to the total number present. Immigration occurred at rates up to 3.6%/annum and was primarily by dispersing males, but is unlikely to be demographically important. We also show that although fox control effectively reduced fox density, there was evidence that control did not reduce the net number of recruits, most likely because the population exhibited a density-dependent release from reproductive suppression. Our results imply that fox control on Phillip Island should primarily focus on reducing on-island abundance and reproduction, but eradication will not be sustained unless immigration ceases.     

Lines in the mud; revisiting the boundaries of important shorebird areas

Many shorebird populations are declining throughout the world, concurrent with declines and degradation of wetland habitats. Such declines necessitate a more consistent approach towards conserving habitats used by shorebird populations. Individuals of many shorebird species congregate in specific areas during their non-breeding season. Worldwide, non-breeding areas are designated as ‘important’ for shorebird conservation based primarily on the abundance of birds found in an area. However, the boundaries of any area are often defined with incomplete information regarding how shorebirds use that habitat. This paper discusses examples in Australia where improved knowledge of shorebird habitat use led to the identification of very different boundaries of important shorebird areas than those identified originally. We highlight how simple questioning of those who count shorebirds in an area, led to an improved understanding of which areas were apparently used by the same local population of non-breeding shorebirds. Subsequent analysis of available count, recapture and/or home range data of particular shorebird species is needed to verify expert opinion regarding most of these boundaries. We review how enhanced boundaries improve the ability of shorebird monitoring to detect population changes; allow management of shorebird habitats at relevant spatial scales; and lead to appropriate designations of important areas. While the kinds of approaches to boundary setting described here are not new, they are not consistently applied worldwide. We suggest additional guidelines to those produced under the Ramsar Convention in regard to designating important areas. We also call for more studies on the movements of migratory shorebirds during the non-breeding season to direct more consistent boundary setting around important non-breeding habitats used by local populations of migratory shorebirds.     

Do Exotic Vertebrates Structure the Biota of Australia? An Experimental Test in New South Wales

From 1993 to 2001, we conducted a series of experiments in a mixed grassland–woodland system in central New South Wales (NSW) to quantify the interactions between red foxes and their prey and competitors. Foxes were removed from two areas around the perimeter of Lake Burrendong, and data were collected from these areas and a nearby untreated area before, during, and after the period of fox control. The arrival of rabbit hemorrhagic disease (RHD) in 1996 provided an opportunity to examine the interactive effects of controlling foxes and rabbits. In this landscape, typical of central NSW, (a) the fox population was not affected by a large reduction in the abundance of rabbits, or vice versa; (b) the cat population declined in areas where foxes were removed after the large RHD-induced reduction in rabbit numbers, but there was no consistent response to the removal of foxes; (c) the abundance of some macropod species increased in response only to the combined removal of rabbits and foxes; (d) there were no consistent changes in the abundances of bird species in response to the removal of either foxes or rabbits, but there were clear habitat differences in bird species richness; and (e) there was likely to be an increase in woody plant species after the large reduction in rabbit populations by RHD. We conclude that (a) long-term field experiments (more than 3 years) are required to quantify the indirect consequences of controlling foxes and rabbits, and (b) single manipulations, such as fox control or rabbit control, are not necessarily sufficient for the conservation of remnant woodland communities in southeastern Australia.     

Genetic characterization of populations of the golden jackal and the red fox in Israel

The golden jackal and red fox are among the wildlife species protected by Israeli law as enforced by the Israel Nature and Parks Authority. In 1964, as a part of a management program to control rabies in Israel, a poison eradication campaign was launched to exterminate golden jackals, considered to be the main reservoir of the disease. The program resulted in the near-complete extermination of jackals in Israel, while foxes were only mildly affected. Jackals have since regained their original numbers and have recolonized southern Israel. We here examined the population structure of the golden jackal and red fox in Israel, 48 years after the poison eradication campaign. DNA from 88 golden jackals and 89 red foxes representing five different geographic regions was extracted and amplified at 13 microsatellite loci in order to characterize the populations on a genetic level. High genetic diversity was found among the jackal and fox populations. A possible migration route through the Jordan Rift Valley was suggested for both species by the genetic similarity of populations in northern and southern Israel. However, in both species, the animals from the center of Israel were distinctive from those north or south, indicating the relative isolation of central populations, likely due to fragmentation or a high abundance of food resources. Genetic profiles obtained for the golden jackal and the red fox in Israel may aid in their conservation management and in the study of zoonotic diseases.     

Possible contemporary evolution in an endangered species, the Santa Cruz Island fox

An ability to mount rapid evolutionary responses to environmental change may be necessary for species persistence in a human-dominated world. We present evidence of the possibility of such contemporary evolution in the anti-predator behaviour of the critically endangered Santa Cruz Island fox Urocyon littoralis . In 1994, golden eagles colonized Santa Cruz Island, CA and devastated the predator-naïve, endemic island fox population by 95% within 10 years. In 1992, just before the arrival of golden eagles, foxes showed substantial diurnal activity, but diurnal activity was 37.0% lower in 2003–2007, after golden eagle colonization; concurrently, overall activity declined and nocturnal activity increased. Moreover, on nearby Santa Catalina Island, where golden eagles were absent but where the fox population recently crashed due to a disease epidemic, remaining foxes were significantly more diurnally active than were those on Santa Cruz Island. The weight of evidence suggests that the change in activity pattern was a response to predation, not to low population density, and that this was probably a heritable rather than a learned behavioural trait. This behavioural change may allow for prolonged island fox persistence, but also potentially represents a loss of behavioural diversity in fox populations.     

Allozymic and biological characters of Trichinella pseudospiralis isolates from free-ranging animals.

To evaluate biological and biochemical variability in nonencapsulated Trichinella isolates, biological and allozymic studies were conducted on isolates of Trichinella collected from a raptoral bird (Aquila rapax) and a fox (Vulpes corsac) in Kazakhstan and from a dasyurid marsupial (Dasyurus maculatus) on the island of Tasmania, Australia. Allozyme profiles of bird and marsupial isolates showed close similarity with the type isolate of Trichinella pseudospiralis. The avian and fox isolates successfully interbred with the type T. pseudospiralis isolate, but they failed to interbreed with 3 encapsulating species, Trichinella spiralis, Trichinella nativa, and Trichinella britovi. The reproductive index assessed in 4 inbred and 1 outbred strains of mice was lower for the avian isolate than for the marsupial and the type T. pseudospiralis isolates (P < 0.001).     

Correlated recovery of five lizard populations following eradication of invasive mammals

Many conservation decisions rely on the assumption that multiple populations will respond similarly to management. However, few attempts have been made to evaluate indicators of population trends (i.e. population indicator species). Eradication of introduced mammals from offshore islands is a commonly used management technique for conservation of native taxa in New Zealand. Pacific rats and rabbits were eradicated from Korapuki Island in 1986/1987 enabling population recovery of native species that had been suppressed by predation or competition. However, the degree to which species’ responses were correlated has not been evaluated. We investigated correlations among lizard population trends on Korapuki Island as a test of the population indicator species concept. Our dataset consisted of captures of the five resident lizard species (three skinks, two geckos) from biannual pitfall trapping over a 10 year period (1986–1995) immediately following rodent eradication. We used a Bayesian modelling approach to examine correlations in population trends (based on mean annual counts) between species. Population trends were positively correlated for all species pairs (substantively for 90 % of pairs) and we detected no negative correlations. Systematic searches for single lizard species may indicate correlated recovery of lizard populations following rodent eradication and provide a cost-effective alternative to traditional ‘whole community’ monitoring. Our findings support evidence-based use of the population indicator species concept in cases where a shared ecological driver can be identified.     

OCCURRENCE OF CODIUM FRAGILE SUBSP. TOMENTOSOIDES (CHLOROPHYTA: BRYOPSIDALES) IN MARINE EMBAYMENTS OF SOUTHEASTERN AUSTRALIA

Codium fragile (Sur.) Hariot subsp. tomentosoides (van Goor) Silva, a widespread weedy species, is reported from Australia for the first time. Specimens were initially found in June 1996 in Corner Inlet, Victoria, where the species fouled fishing nets. This invasive chlorophycean alga was subsequently found in large numbers on 30 January 1997 in Port Phillip Bay and on 9 March 1998 in Western Port, Victoria. Presumably the species is native to Japan. The alga formed dense stands on rocky substrata in intertidal or in subtidal regions. In Port Phillip Bay, the species was also found attached to the common blue mussel Mytilus edulis planulatus Lamarck, and in Western Port it was found attached to the mud oyster Ostrea angasi Sowerby. Results of this study suggest that recruitment of juvenile germlings and growth of C. fragile subsp. tomentosoides differs between populations in Port Phillip Bay and those in Western Port.     

A virgin flight across the Tasman Sea? Satellite tracking of post-fledging movement in the Australasian Gannet Morus serrator

New technologies enable tracking of the route, duration, and destination of previously unassessed long-distance movements. Fledgling Australasian Gannets Morus serrator from breeding populations in New Zealand had been reported to fly across the Tasman Sea to Australia, with this historic knowledge derived from the recovery of banded carcasses and from observations of initial flight direction. We deployed Argos satellite devices on ten M. serrator fledglings at Cape Kidnappers Gannetry, North Island, New Zealand, across 2 years. Birds that were tracked leaving the colony initially appeared to have landed on the sea. A male bird and two female birds were tracked moving along the east coast to the south tip of New Zealand. The two females then crossed the Tasman Sea to eastern Australian coastal waters in 4 and 5 days, respectively. We suggest that, contrary to historic reports, the route via Stewart Island constitutes a realized migration path for fledglings from Cape Kidnappers, which might minimize the distance traveled across the open sea to southeastern Australia or Tasmania. Our results further imply that initial direction of flight needs not be indicative of the subsequent migration route taken by M. serrator. This highlights the importance of direct tracking technology for adequate assessment of dispersal and migration in seabirds and other highly mobile species.     

The recent spread of <Emphasis Type="Italic">Artemia parthenogenetica</Emphasis> in Western Australia

In Western Australia, populations of Artemia parthenogenetica in coastal salt lakes at Rottnest Island and Lake Hayward, and in salterns at Port Hedland and Shark Bay, are widely accepted to have been introduced by humans. Further, within the past 10 years, populations of A. parthenogenetica have been found in inland playa salt lakes in the wheatbelt of south-west Western Australia, where none had been recorded in previous salt lake studies. Here we hypothesise that birds act as transport vectors for Artemia cysts both within Australia and between the Asian and Australian continents. Allozyme analysis was used to identify clonal types (multi-locus genotypes), clonal frequencies, genotypic diversities and genotypic identity of six populations (three coastal, three inland). Overall, the inland populations displayed almost identical genotypic structure to the coastal population from Lake Hayward, indicating that Lake Hayward could be the major source for dispersal and colonisation of inland populations. Results support the hypothesis of dispersal inland by nomadic bird species. Furthermore, evidence suggests that the inland and Lake Hayward populations may be an example of a metapopulation. The greater variety of genotypes present in the Rottnest population indicates that this population has received a large number of small immigrations, or that it received one large introduction. The former may indicate a long period of suitable salinities, providing a greater time-span over which migration and succession of clonal types could occur in comparison to other populations. While we cannot rule out the possibility of human introduction of A. parthenogenetica to Rottnest, the hypothesis of cyst dispersal along the Austral-Asian flyway remains possible. Guest Editor: John M. Melack Saline Waters and their Biota     

Genetic similarity and hatching success in birds

The ecological correlates of fitness costs of genetic similarity in free-living, large populations of organisms are poorly understood. Using a dataset of genetic similarity as reflected by band-sharing coefficients of minisatellites, we show that bird species with higher genetic similarity experience elevated hatching failure of eggs, increasing by a factor of six across 99 species. Island distributions and cooperative breeding systems in particular were associated with elevated genetic similarity. These findings provide comparative evidence of detrimental fitness consequences of high genetic similarity across a wide range of species, and help to identify ecological factors potentially associated with increased risk of extinction.     

Adaptive divergence despite strong genetic drift: genomic analysis of the evolutionary mechanisms causing genetic differentiation in the island fox (Urocyon littoralis)

The evolutionary mechanisms generating the tremendous biodiversity of islands have long fascinated evolutionary biologists. Genetic drift and divergent selection are predicted to be strong on islands and both could drive population divergence and speciation. Alternatively, strong genetic drift may preclude adaptation. We conducted a genomic analysis to test the roles of genetic drift and divergent selection in causing genetic differentiation among populations of the island fox (Urocyon littoralis). This species consists of six subspecies, each of which occupies a different California Channel Island. Analysis of 5293 SNP loci generated using Restriction‐site Associated DNA (RAD) sequencing found support for genetic drift as the dominant evolutionary mechanism driving population divergence among island fox populations. In particular, populations had exceptionally low genetic variation, small N_e (range = 2.1–89.7; median = 19.4), and significant genetic signatures of bottlenecks. Moreover, islands with the lowest genetic variation (and, by inference, the strongest historical genetic drift) were most genetically differentiated from mainland grey foxes, and vice versa, indicating genetic drift drives genome‐wide divergence. Nonetheless, outlier tests identified 3.6–6.6% of loci as high F_ST outliers, suggesting that despite strong genetic drift, divergent selection contributes to population divergence. Patterns of similarity among populations based on high F_ST outliers mirrored patterns based on morphology, providing additional evidence that outliers reflect adaptive divergence. Extremely low genetic variation and small N_e in some island fox populations, particularly on San Nicolas Island, suggest that they may be vulnerable to fixation of deleterious alleles, decreased fitness and reduced adaptive potential.