Peron Peninsula Research Articles

Complementary evidence for small-scale spatial assemblages of the exploited grass emperor (Lethrinus laticaudis) in the Shark Bay World Heritage Area, Western Australia

Understanding the connectivity of exploited fish populations is critical to their management under both rapid and long-term environmental change. Patterns of connectivity are unknown for most fishes in the Shark Bay World Heritage Area (Western Australia), a large, shallow embayment in the eastern Indian Ocean, vulnerable to marine heatwaves. The composition of oxygen (δ18O) and carbon (δ13C) stable isotopes in whole otoliths of the recreationally-important reef fish Lethrinus laticaudis did not differ between Shark Bay's two large inner gulfs, separated by the Peron Peninsula. However, significant differences were found between pairs of locations with different salinities over a spatial scale of ∼60 km within each gulf. Misclassification of samples was greatest between locations mostly in different gulfs, but with similar salinities (15–41%), and rare between adjacent locations in the same gulf with different salinities (0–5%). This is influenced by the strong correlation (ρ = 0.93) between δ18O in otoliths and the salinity gradient of the two gulfs, and further supported by a lack of correlation in the similarities of isotope compositions and distances between locations (ρ = 0.16). Fish samples from each of the different locations were composed of multiple year-classes, yet the otolith chemistry distinguished them at a minimum distance of 16 km apart, indicating that small-scale connectivity of L. laticaudis is likely during the majority of their life cycle. Physical barriers to movement of post-settlement individuals (land masses, expansive seagrass and sand) between the small, isolated reefs of Shark Bay may reduce large scale connectivity, which instead would occur mostly by egg and larval dispersal. The probable scale of connectivity of post-settlement L. laticaudis indicates that this major recreational fishing target species may be vulnerable to localised over-exploitation and negative environmental effects on population sources and sinks within this shallow embayment. Maintaining sustainable spawning biomass at scales relevant to the extent of connectivity for such a species in a World Heritage Area is an important management consideration.

Male aggression varies with consortship rate and habitat in a dolphin social network

Coalitions and alliances exemplify the core elements of conflict and cooperation in animal societies. Ecological influences on alliance formation are more readily attributed to within-species variation where phylogenetic signals are muted. Remarkably, male Indo-Pacific bottlenose dolphins in Shark Bay, Western Australia, exhibit systematic spatial variation in alliance behavior, not simply within a species or population, but within a single social network. Moving SE-NW along Peron Peninsula in Shark Bay, males ally more often in trios than pairs, consort females more often, and exhibit greater seasonal movements. Ecological models predict more male-male conflict in the north, but sufficient observations of aggression are lacking. However, dolphins often incur marks, in the form of tooth rakes, during conflicts. Here we report that the incidence of new tooth rake marks varies systematically in the predicted pattern, with greater marking in the north, where males form more trios and consort females at a higher rate. While our previous work demonstrated that alliance complexity has an ecological component, we can now infer that ecological variation impacts the level of alliance-related conflict in Shark Bay. To understand ecological influences on animal societies, researchers have focused on differences within species, where confounds due to evolutionary history are minimized. Such differences are usually found among geographically separated populations, but in Shark Bay, Western Australia, male dolphin alliance size and access to females increase along a spatial axis within a single social network. Here we report that aggression levels, evidenced by tooth rake marks, increase along the same axis. Alliances are of particular interest as they represent a complex kind of relationship, often implicated in the evolution of social intelligence. Our discovery of spatial variation in alliance behavior and aggression within a social network provides a unique opportunity to investigate the intersection of cognition, social structure, and ecology.

Effects of chaining and burning in Acacia ramulosa shrublands of the Peron Peninsula, Shark Bay, Western Australia

We tested the effect of chained and burnt buffers installed across the Peron Peninsula at Shark Bay, Western Australia, in 1995 on the plant communities. Chaining modified fuel by flattening shrubs to provide a more continuous fuel bed by adding vertically arranged shrub fuel to the in situ sparse ground fuels. Twenty-six, 10 × 10-m permanent plots were established in the treated buffers and adjacent untreated shrubland. Plots were evaluated in 1996, 2001 and 2008. By 1996, fire and chaining had promoted a suite of species that included 29 not observed in adjacent untreated shrubland. High rainfall before the 2001 assessment produced an increase in species richness in both burnt and unburnt treatments. By 2008, 20 of the 29 fire-promoted species were found in the untreated area after rainfall leaving nine species uniquely responsive to the fire and chaining treatment. The Acacia ramulosa W.Fitzg. sandplain communities in our study area appear to be sustained by high rainfall years promoting regeneration of 84% of species with a smaller proportion (16%) regenerated only in burnt areas. The dominance of periodic rainfall in promoting regeneration led to the likely reduced effectiveness of the fire buffers in preventing the spread of fire. There is the potential for extensive fires in this landscape following favourable rainfall.

Population structure and management of invasive cats on an Australian Island

Invasive predators have a major impact on endemic island species; therefore, information about invasion dynamics are essential for implementing successful control measures. The introduction of feral cats onto Dirk Hartog Island, Western Australia, has had devastating effects, with presumably 10 of 13 native terrestrial mammal species being lost because of predation. Detailed records of historical introduction events were lacking; therefore, we analyzed genetic variation of the current population to gain information about past invasion dynamics and current gene-flow patterns. We analyzed the genetic structure and diversity of feral cats on the island and 2 mainland populations (Peron Peninsula and Steep Point). Analysis of mitochondrial DNA (ND5 and ND6) showed 2 primary haplotypes that we attribute to 2 main introduction events. Pairwise G 00 ST values indicated high connectivity on the island but some isolation to the mainland populations. Mitochondrial and nuclear data showed no evidence for genetic differentiation of island and mainland populations; however, kinship analyses rejected evidence for on-going immigration of members of the current cat populations. Overall, our data suggested that gene flow following the main introduction events ceased some years ago. Because current island populations appear to be reproductively isolated from mainland populations, a sufficiently large-scale eradication measure might successfully diminish feral cat populations long-term. 2014 The Wildlife Society.

Predicting bait uptake by feral cats, Felis catus, in semi‐arid environments

SummaryFeral cat control using aerial broadcasting of toxic baits continues to be used in the rangelands of Western Australia. The effectiveness of these operations has sometimes been compromised by different environmental factors that affect prey and cat numbers. This study demonstrates that the ratio of cats to their preferred prey (small mammals) can be used to predict the most effective time to bait. The regular baiting of three conservation sites offered an opportunity to study the relationship between feral cat abundance, the abundance of their prey and ingestion of toxic baits. Peron Peninsula on the mid‐west coast, Lorna Glen station in the northern Goldfields and the central Gibson Desert of Western Australia are sites where cat control using toxic baits has been routinely applied over the last 15 years. We postulated that bait ingestion by cats was linked to the availability of live prey. Small mammal abundance (capture rates in pit‐fall traps) and relative cat abundance (based on daily track counts) were assessed at these sites and the data used to produce a predator‐prey ratio index (PPRI). We used generalised linear mixed models to test the effect of prey abundance, prebaiting cat abundance and PPRI on baiting efficacy (BE). The best model for predicting efficacy of baiting contained only PPRI. This simple model was able to predict baiting success over the entire range of outcomes, from highly successful ( >75% cat reduction) to unsuccessful (0% cat reduction). The ability to predict feral cat BE in advance of planned toxic baiting operations will provide a valuable tool for wildlife managers involved in cat control.

The herpetofauna of Faure Island, Shark Bay, Western Australia

The currently recorded Fame Island herpetofauna comprises 24 species of reptile. This is a strict subset of the more diverse herpetofauna recorded from adjacent Peron Peninsula. Wc describe the broader geographic distributions and habitat associations of each species, and discuss the biogeography of the island herpelofauna in the context of the Carnarvon Basin biogeographic region. The reduced island diversity is presumably due to a combination of lesser sampling effort and'drop out' extinctions following drowning of the continental shelf and severance of the island around 6S00 years ago.

Importance of diurnal refugia to a hare-wallaby reintroduction in Western Australia

In an effort to learn more about the potential for reintroduction of hare-wallabies to sites in Australia, 34 captive-bred hare-wallabies were released onto Peron Peninsula within the Shark Bay World Heritage Property in 2001 as part of an experimental reintroduction program. One objective of this experiment was to characterise their behaviour and daytime refugia to identify suitable habitat for future releases. The mala (Lagorchestes hirsutus) and merrnine (Lagostrophus fasciatus) were fitted with radio-transmitters and tracked daily. Merrnine were more faithful to a previously occupied shelter than mala. Mala maintained a solitary daytime habit at all times. Within the study area, mala preferentially sought low-lying vegetation primarily comprising the species Lamarchea hakeifolia, which provided dense cover up to 1 m in height, under which they constructed scrapes. L. hakeifolia was preferred as shelter vegetation instead of Triodia (spinifex) hummocks, despite Triodia hummock habitat being preferred by mala in central Australia. Merrnine occupied taller vegetation with an open understorey to 1.5 m, although the extremity of the understorey remained dense at this height. Individual merrnine sometimes sheltered with conspecifics of the opposite sex. Since both species utilised floristically and structurally variable vegetation, we suggest that they have the ability to cope with vegetation that has been altered by changes in fire regimes and introduced herbivores. This is particularly important for future reintroduction exercises as the results suggest that vegetation characteristics required to support these species, particularly mala, may be variable rather than limited to perceived necessary habitat types in central Australia or on islands. These results should allow future reintroduction projects to consider a wider range of release-site options during their planning phase.

Optimising reintroduction success by delayed dispersal: Is the release protocol important for hare-wallabies?

The transfer of threatened animals from one location to another in order to benefit the species is a technique frequently used by animal conservation managers. However, very few of these relocations have experimentally assessed the relative merits and disadvantages of commonly used release techniques. The premise examined in this study was that a higher degree of site fidelity should be advantageous for an individual through a soft release protocol. Two species of hare-wallaby, mala ( Lagorchestes hirsutus) and merrnine ( Lagostrophus fasciatus), were fitted with radio-collars and reintroduced in August 2001 onto Peron Peninsula in Western Australia. These threatened species were reintroduced using two release strategies (soft versus hard release), and their movements and body condition were monitored, for a period of four weeks post-release, using radio-telemetry and trapping. Each species averaged decreases in body condition index when exposed to both experimental release protocols. A total of 11 animals (32%) emigrated from the release sites, with 10 of these animals being male. Importantly, no relationship was found between site fidelity and release method, although body condition was significantly higher in mala which dispersed, and there was observational evidence for a male-biased dispersal for merrnine. Although the number of released individuals of each species was low, this study demonstrates an interesting trend which indicates that soft release techniques do not necessarily to confer an advantage to the successful immediate establishment and survival of either hare-wallaby species in the short term. We recommend that managers involved with species reintroduction programs consider the costs and potential outcomes of designing and installing soft release enclosures.

Biology of the Southern Scrub-robin (Drymodes brunneopygia) at Peron Peninsula, Western Australia

The ecology of the Southern Scrub-robin was examined at a 55-ha study site on the eastern side of Peron Peninsula, Western Australia. The scrub-robin was a sedentary, ground-dwelling species occurring in pairs, and sometimes alone. Pairs maintained permanent, all-purpose territories throughout the year, and males regularly defended the boundaries of their territories by song and by chasing intruders. Territory sizes ranged from 2.8 to 7.1 ha, with a mean of 4.0 ha. The female alone was observed building the nest and incubating the one egg, but both adults were seen feeding young. The incubation period was estimated at 16 days and the nestling period at 9–12 days. Scrub-robins primarily gleaned prey from leaf litter and sand. Analysis of scats showed that ants comprised a major component of the diet in both spring and summer. Other dietary items in spring included beetles, lepidopteran larvae, termites, hemipterans, spiders and fruit of Enchylaena tomentosa. In summer there was a higher proportion of termites in scats than in spring. The ant fauna within scrub-robin scats was dominated by a species of Iridomyrmex and a species of Crematogaster, both 2–3 mm in length. The Crematogaster species was selected more frequently than it occurred in litter samples, while the Iridomyrmex species was eaten in a lower proportion than sampled in the litter. The scrub-robin's use of litter substrates for feeding and nesting, and its clutch size of one and potentially low reproductive rate, suggest that it may be vulnerable to changes in the quantity and quality of the litter layer in the Western Australian wheatbelt.

The range and habitat characteristics of the thick-billed grasswren (Amytornis textilis) in the Shark Bay region, Western Australia

The thick-billed grasswren (Amytornis textilis) has a disjunct distribution in the Shark Bay region, with one population confined to Peron Peninsula and the other further inland on Woodleigh Station and the north-eastern corner of Hamelin Station. Grasswrens were found in several vegetation types, including acacia shrublands, Triodia spinifex and the dense vegetation in drainage depressions. Vegetation characteristics that appeared important determinants of grasswren presence were recumbent acacias and low shrubs within the 0–1-m height category, and shrub clumps of high foliage density. These shrub clumps comprised climbers and recumbent low shrubs with interwoven branches, often in association with other plant species. Habitats with this shrub structure may provide the grasswren with ideal nesting sites. The possible effects of grazing and fire on this shrub structure are discussed.

The excavation of two small rockshelters at Monkey Mia, Shark Bay, Western Australia

The first archaeological excavations at Shark Bay were carried out in 1986, in two small rockshelters at Monkey Mia, on the east side of Peron Peninsula. These were designed as test excavations only. It is unlikely that further excavation of these sites will be carried out in the foreseeable future, as the amount of deposit in each shelter is very small, and it is not expected that much additional information would be gained. It seems however useful to document the results as I believe they are of relevance to the overall emerging picture of past human occupation in the Shark Bay region. A general view of the Shark Bay archaeological research program to 1990 has already been published (Bowdler 1990a, 1990b).

The Status of Birds on Peron Peninsula and Dirk Hartog Island, Shark Bay, Wa

Details of observations made during a field excursion by the Western Australian Group of the RAOU to Peron Peninsula and Dirk Hartog Island are given and comuared with other reuorts on the birds of the area, which has not been greatlyhisturbed, except round enh ham and near sheefstations. Permanent water has been provided for stock. A few species have not been recorded recently, notably the Rock Parrot (from Peron and Dirk Hartog) and the Western Grass-wren (from Dirk Hartog), but some others seem to have arrived in the last fifty years. The ornithology of the area is well documented and can provide an interest- ing study of changes in distribution and abundance of species related to development by Europeans.

Notes on Dirk Hartog Island and Peron Peninsula, Shark Bay, Western Australia

Notes on Dirk Hartog Island and Peron Peninsula, Shark Bay, Western Australia

XXX.‐TTIIe Birds of Dirk Hart0.9 Island and Peron Peninsula, Shark Bay, Western Australia, 191 6‐17

IbisVolume 59, Issue 4 p. 564-610 XXX.-TTIIe Birds of Dirk Hart0.9 Island and Peron Peninsula, Shark Bay, Western Australia, 191 6-17 THOMAS CARTER M.B.O.U., THOMAS CARTER M.B.O.U.Search for more papers by this author THOMAS CARTER M.B.O.U., THOMAS CARTER M.B.O.U.Search for more papers by this author First published: October 1917 https://doi.org/10.1111/j.1474-919X.1917.tb00570.xCitations: 1AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume59, Issue4October 1917Pages 564-610 RelatedInformation