Lord Howe Island Research Articles

Applying acoustic telemetry, vessel tracking and fisher knowledge to investigate and manage fisher-shark conflict at Lord Howe Island, Australia

Fisher-shark conflict is occurring at Lord Howe Island, Australia due to high levels of Galapagos shark (Carcharhinus galapagensis) depredation (where sharks consume hooked fish) and bycatch. Depredation causes costly loss of target catch and fishing gear and increased mortality of target species, and sharks can be injured or killed when bycaught. This study applied acoustic telemetry and vessel tracking from 2018 to 2021 to identify; (1) how the movements of 30 tagged sharks and activity of six fishing vessels overlapped, and (2) where key ‘hotspots’ of overlap occurred. Fisher surveys were also conducted to collect information about mitigating shark interactions. Residency index analysis indicated that three sharks tagged at a fish waste dumping site had markedly higher residency. Core home ranges of sharks overlapped with higher fishing activity at four ‘hotspots’. Statistical modelling indicated positive linear effects of fishing activity and bathymetric complexity on shark detections and tagged sharks were present for 13% of the total time that vessels were fishing close to acoustic receivers. Spatio-temporal overlaps between shark movements and fishing activity could potentially have occurred because sharks learned to associate fishing vessels with food (i.e. hooked fish) and because fishers and sharks utilise highly productive shelf edge areas, however more research is needed to investigate these relationships. Fishers reported that rotating fishing areas and reducing time at each location, fishing deeper than 100 m, and using electric reels and lures instead of bait, reduced bycatch and depredation. The integrated approach used here identified practical methods for reducing fisher-shark conflict, improving socio-economic outcomes for fishers and conservation prospects for this unique shark population.

Gene flow stimulates recovery of reproductive fitness in a captive bred insect

Abstract Captive breeding can be a useful tool for the management of threatened species, but such programs often begin with a bottleneck which may lower reproductive fitness by increasing inbreeding and allowing deleterious alleles to increase in frequency by reducing effective population size. Dryococelus australis, the Lord Howe Island stick insect, is a critically endangered insect that has been bred at the Melbourne Zoo in Melbourne, Australia, since shortly after the species was rediscovered in 2001. We analysed a long‐term dataset of phenotypic measurements from this captive breeding program to determine whether reproductive fitness has declined in captivity. We found a clear signal of decline in direct (egg hatching success) and indirect (egg and nymph size) fitness indicators over time. We compared a captive line descended from the original program founders to a new hybrid line that has recent wild ancestry. The hybrid line showed an immediate improvement in egg hatch rate, suggesting the potential for genetic rescue. Egg and nymph size did not show as dramatic a change, although this line had only existed for just over a single generation at the time of data collection. These results argue strongly for the regular sourcing of new genetic material from the wild D. australis population to counteract fitness declines in captivity. Aside from benefiting the captive population, this would also improve the prospects of establishing new wild populations in the future, using individuals sourced from captivity.

Plio‐Pleistocene decline of mesic forest underpins diversification in a clade of Australian Panesthia cockroaches

AbstractThe progressive aridification of the Australian continent, and coincident decline of mesic forest, has been a powerful driver of allopatric and environmental speciation in native species. The relictual mesic forests of the eastern seaboard now harbour a diverse group of endemic fauna, including the wood‐feeding cockroaches of the genus Panesthia, which reached the continent via two separate invasions from Melanesia. The more recent of these colonization events gave rise to a group of five recognized species, occurring in mainland woodlands, sclerophylls and rainforests, as well as the forests and grasslands of the Lord Howe Island Group. Due to limited sampling in molecular studies and doubt regarding the standing taxonomy, there is little certainty about relationships among the species and poor understanding of the effects of ancient climatic change upon their evolution. We undertook a comprehensive phylogenetic analysis of the clade, using complete mitogenomes and nuclear ribosomal markers from nearly all known morphospecies and populations. Our time‐calibrated phylogenetic analyses reveal an additional six unrecognized, highly divergent lineages and suggest that these have arisen primarily through vicariance as rainforests fragmented during Plio‐Pleistocene glacial cycles (2–5 million years ago). Ancestral niche estimations also evidence a tropical rainforest origin for the group, followed by at least three niche transitions into drier forest, including one associated with the singular colonization of the Lord Howe Island Group. Finally, we find evidence of frequent, parallel wing reduction, in potential association with the contraction of forest habitats into small refugia. Our results reiterate the far‐reaching role of ancient aridification in driving speciation, niche expansion and morphological evolution in Australian fauna.

Evolution of Placentation in Eugongylini (Squamata: Scincidae): Ontogeny of Extraembryonic Membranes in Oviparous and Viviparous Species of New Zealand.

New Zealand scincid lizards, genus Oligosoma, represent a monophyletic radiation of a clade, Eugongylini, of species distributed geographically throughout the South Pacific with major radiations in Australia and New Caledonia. Viviparity has evolved independently on multiple occasions within these lineages. Studies of Australian species have revealed that placental specializations resulting in substantial placentotrophy have evolved in two lineages. The pattern of extraembryonic membrane development of oviparous species differs from viviparous species and identical placental architecture has evolved in both placentotrophic lineages. We analyzed extraembryonic membrane development in two New Zealand species, the sole oviparous species, Oligosoma suteri, and placental development of a representative viviparous species, Oligosoma polychroma, using histological techniques. We conclude that these two species share a basic pattern of extraembryonic membrane development with other squamates. Comparisons with Australian species indicate that morphogenesis of the yolk sac of O. suteri results in an elaborate structure previously known only in Oligosoma lichenigerum with a geographic distribution on Lord Howe Island and Norfolk Island. This finding supports a close relationship between these two taxa. We conclude also that the pattern of placental development of O. polychroma is identical to that of viviparous species of Australia. The terminal placental stage for each of these lineages includes a chorioallantoic placenta and an elaborate omphaloplacenta. This level of homoplasy in placental evolution is consistent with a hypothesis that selection favors regional differentiation of the maternal-embryonic interface and that the omphaloplacenta is an adaptation for histotrophic transport.

Size does matter: integrative taxonomy and size evolution of threatened charopid land snails on Lord Howe Island (Gastropoda: Stylommatophora)

Size does matter: integrative taxonomy and size evolution of threatened charopid land snails on Lord Howe Island (Gastropoda: Stylommatophora)

The use of vibrational spectroscopy and supervised machine learning for chemical identification of plastics ingested by seabirds

Plastic pollution is now ubiquitous in the environment and represents a growing threat to wildlife, who can mistake plastic for food and ingest it. Tackling this problem requires reliable, consistent methods for monitoring plastic pollution ingested by seabirds and other marine fauna, including methods for identifying different types of plastic. This study presents a robust method for the rapid, reliable chemical characterisation of ingested plastics in the 1–50 mm size range using infrared and Raman spectroscopy. We analysed 246 objects ingested by Flesh-footed Shearwaters (Ardenna carneipes) from Lord Howe Island, Australia, and compared the data yielded by each technique: 92 % of ingested objects visually identified as plastic were confirmed by spectroscopy, 98 % of those were low density polymers such as polyethylene, polypropylene, or their copolymers. Ingested plastics exhibit significant spectral evidence of biological contamination compared to other reports, which hinders identification by conventional library searching. Machine learning can be used to identify ingested plastics by their vibrational spectra with up to 93 % accuracy. Overall, we find that infrared is the more effective technique for identifying ingested plastics in this size range, and that appropriately trained machine learning models can be superior to conventional library searching methods for identifying plastics.

A review of the relationships of the Tateidae of Lord Howe Island

ABSTRACT An analysis of two mitochondrial genes (16S and COI) shows that two genera can be recognised in the Lord Howe Island tateid fauna. Fluviopupa, a widespread Pacific genus, contains the species previously referred to that genus as well as Potamopyrgus oscitans. Species which were previously included in the New Caledonian genus Hemistomia form a clade that is sister to Austropyrgus from south-eastern Australia. The generic name Insuladrobia n. gen. is introduced for that clade. http://zoobank.org/urn:lsid:zoobank.org:pub:75E8D474-47E7-4B4E-B6F1-56924540D9C5

Seabird transported contaminants are dispersed in island ecosystems

Seabirds are long-range transporters of nutrients and contaminants, linking marine feeding areas with terrestrial breeding and roosting sites. By depositing nutrient-rich guano, which acts as a fertiliser, seabirds can substantially influence the terrestrial environment in which they reside. However, increasing pollution of the marine environment has resulted in guano becoming similarly polluted. Here, we determined metal and metalloid concentrations (As, Cd, Cr, Cu, Hg, Pb) in Flesh-footed Shearwater (Ardenna carneipes) guano, soil, terrestrial flora, and primary consumers and used an ecological approach to assess whether the trace elements in guano were bioaccumulating and contaminating the surrounding environment. Concentrations in guano were higher than those of other Procellariiformes documented in the literature, which may be influenced by the high amounts of plastics that this species of shearwater ingests. Soil samples from shearwater colonies had significantly higher concentrations of all metals, except for Pb, than soils from control sites and formerly occupied areas. Concentrations in terrestrial primary producers and primary consumers were not as marked, and for many contaminants there was no significant difference observed across levels of ornithogenic input. We conclude that Flesh-footed Shearwaters are transporters of marine derived contaminants to the Lord Howe Island terrestrial environment.

Mixed stock analysis identifies natal origins of green turtles at foraging grounds in southeastern Australia

IntroductionIdentifying critical habitats for marine turtles and connectivity between genetic stocks and the foraging grounds they use is a conservation priority worldwide. Green turtles (Chelonia mydas) are impacted by a wide range of anthropogenic threats that can vary by geographic region and the ontogenetic stage of the individual. In Australia, the strengthening of the East Australian Current due to climate change is increasing ocean temperatures, particularly in southern New South Wales (NSW), which is having large-scale impacts on the distribution and abundance of marine resources. Green turtles are frequently observed in temperate southern NSW waters, but our knowledge of their habitat use, migration patterns and the impact of threatening processes is limited.MethodsTo assess the origins of green turtles from foraging grounds in southeastern Australia, samples were obtained from green turtles of all size classes (post-hatchlings to adults) that had stranded along an ~870 km expanse of the NSW coast and Lord Howe Island between 1997 and 2021. Mitochondrial DNA control region sequences for 283 individuals were compared to 25 potential source genetic stocks in the Indo-Pacific using mixed-stock analysis.ResultsA total of 26 haplotypes were identified in NSW, of which 14 had been previously observed at a rookery, eight had been identified previously, but not at a rookery (i.e. orphan haplotypes), and four were previously undescribed. Mixed-stock analysis revealed that NSW waters support multiple genetic stocks but are dominated by those of the southern Great Barrier Reef and New Caledonia genetic stocks. A small proportion of green turtles originated from more distant stocks in the Indo-Pacific region.DiscussionUnderstanding the connectivity between green turtle rookeries and foraging grounds provides an opportunity to assess the impact of anthropogenic threats to turtle stocks, and in turn, prioritize management actions for the conservation of green turtles across regional, national and international jurisdictions.

Recovery of a flightless beetle after elimination of rodents on Lord Howe Island, Australia

Recovery of a flightless beetle after elimination of rodents on Lord Howe Island, Australia

Detection and Differentiation of Entomopathogenic Serratia spp. to Inform Reintroduction of the Critically Endangered Lord Howe Island Stick Insect Dryococelus australis.

Once rodents have been successfully eradicated from Lord Howe Island, Australia, the critically endangered Lord Howe Island stick insect (Dryococelus australis (Montrouzier)) may be reintroduced, a century after it was thought to have become extinct. In captive populations of D. australis, elevated mortalities have been associated with bacterial pathogens. To better define the infectious risk posed by entomopathogens to the reintroduction program, we investigated the bacteria isolated from captive D. australis kept at Melbourne Zoo and on Lord Howe Island and from environmental samples and free-living invertebrates collected on various parts of the island. At Melbourne Zoo, Serratia and Pseudomonas spp. were the bacteria most frequently isolated between 2013 and 2019. Serratia spp. were also the organisms most frequently isolated from insects sampled in April 2019 from the captive population on Lord Howe Island. In addition, Serratia spp. were isolated from a range of environmental samples collected on Lord Howe Island during March-April 2019. These environmental isolates had a broader range of biochemical and molecular characteristics than those obtained from the captive insect populations. A large proportion of these isolates were urease positive and had biochemical profiles previously not described for Serratia spp. This study highlights the need for better surveillance for potential pathogens in understudied regions and sites. We conclude that infections caused by Serratia spp. might pose a problem to the captive breeding program for D. australis but that the risk of introducing novel pathogens to Lord Howe Island through infected insects is low. Our study explores some of the potential risks involved in captive breeding and provides a valuable example of using pathogen surveillance to better inform an invertebrate conservation program.

Extinct Australian birds: numbers, characteristics, lessons and prospects

ABSTRACT Since European colonisation of Australia in 1788, nine Australian bird species (1.2% of the Australian total) have become extinct, along with 22 subspecies (of 16 species). Consistent with global patterns, Australia’s island endemic birds have been particularly susceptible, comprising eight of the nine species’ extinctions (38% of the bird species endemic to islands smaller than Tasmania), and 13 of the 22 subspecies’ extinctions. The extinction of only one bird species (Paradise Parrot Psephotellus pulcherrimus) from the Australian mainland contrasts with the far higher rate of extinctions of Australian mammals (27 of 312 species that occurred on the Australian mainland), and is comparable with the rate of extinctions of birds on the mainland of other continents over this period. Extinctions of Australian birds were caused mainly by introduced predators (especially for island taxa), habitat degradation, and hunting (for some island taxa). The timing of some extinctions is uncertain, but the first bird extinction subsequent to European colonisation was the loss of the flightless White Gallinule Porphyrio albus from Lord Howe Island over the period 1788–1790. Extinctions have occurred in most decades since then, with the most recent being for Norfolk Island’s White-chested White-eye Zosterops albogularis in the decade 2000–2009. Environmental legislation, an extensive conservation reserve system, and dedicated conservation management efforts have prevented some extinctions. However, local extirpations continue, many threatened species continue to decline and, without an increase in conservation efforts, the rate of extinctions is likely to increase, mainly due to the direct and compounding impacts of climate change.

Ecological speciation in sympatric palms: 5. Evidence for pleiotropic speciation genes using gene knockout and high-throughput phenotyping

Abstract Theoretical models predict that sympatric, ecological speciation may be facilitated more readily when so-called ‘magic traits’ are present, linking traits under divergent selection with assortative mating. Such traits might be encoded by pleiotropic genes, that is, genes that affect multiple, apparently unrelated, phenotypes. However, few convincing examples of sympatric speciation exist, and empirical evidence for the role of magic traits in driving such speciation is rare. One of the strongest cases of sympatric speciation is the Howea palms of Lord Howe Island, Australia, comprising the sister species Howea belmoreana and Howea forsteriana, which have diverged due to soil substrate preferences and flowering time displacement. Here we investigate the role that pleiotropy may have played in the speciation process by carrying out high-throughput phenotyping experiments using 1830 Arabidopsis thaliana plants with knockouts of candidate Howea ‘speciation genes’. We identify several genes that show signatures of adaptive divergence between the Howea species and demonstrate pleiotropic roles in soil stress tolerance and flowering time, consistent with the Howea speciation scenario—notably, Howea orthologues of the A. thaliana loci At2-MMP, DCL1, RCD1, SAL1, and SIZ1. Empirical evidence is provided, therefore, for a range of pleiotropic genes with the potential to have driven sympatric speciation by generating magic traits which link divergent selection to non-random mating.

Quantitative photography for rapid, reliable measurement of marine macro‐plastic pollution

Abstract Plastics are now ubiquitous in the environment and have been studied in wildlife and in ecosystems for more than 50 years. Measurement of size, shape and colour data for individual fragments of plastic is labour‐intensive, unreliable and prone to observer bias, particularly when it comes to assessment of colour, which relies on arbitrary and inconsistently defined colour categorisations. There is a clear need for a standard method for data collection on plastic pollution, particularly one that can be readily automated given the number of samples involved. This study describes a new method for standardised photography of marine plastics in the 1–100 mm size range (meso‐ and macro‐plastics), including colour correction to account for any image‐to‐image variation in lighting that may impact colour reproduction or apparent brightness. Automated image analysis is then applied to detect individual fragments of plastic for quantitative measurement of size, shape, and colour. The method was tested on 3793 fragments of debris ingested by Flesh‐footed Shearwaters (Ardenna carneipes) on Lord Howe Island, Australia, and compare results from photos taken in two separate locations using different equipment. Photos were acquired of up to 250 fragments at a time with a spatial resolution of 70 μm/pixel and were colour‐corrected using a reference chart to ensure accurate reproduction of colour. The automated image analysis pipeline was found to have a 98% success rate at detecting fragments, and the different size and shape parameters that can be outputted by the pipeline were compared in terms of usefulness. The evidence shown in this study should strongly encourage the uptake of this method for cataloguing macro‐scale plastic pollution, as it provides substantially higher quality data with accurate, reliable measurements of size, shape and colour for individual plastics that can be readily compared between disparate datasets.

The oribatid mite superfamily Eutegaeoidea (Acari, Oribatida), with descriptions of new taxa from Australia and New Caledonia and a re-assessment of genera and families.

Twenty-four new species of Eutegaeoidea from Australia and New Caledonia are described, and two new genera are proposed. These are Eutegaeus woiwurrung sp. nov., E. nothofagi sp. nov., E. bidhawal sp. nov., E. ptilosus sp. nov., Humerotegaeus carinatus gen. et sp. nov., H. concentricus gen. et sp. nov., Atalotegaeus crobylus sp. nov., Neoeutegaeus torsteini sp. nov., N. melipsilon sp. nov. N. malcolmi sp. nov., N. corniculatus sp. nov. (Eutegaeidae), Compactozetes goongerah sp. nov., C. crenellatus sp. nov. (Compactozetidae) and Pterozetes lawrencei sp. nov. (Pterozetidae) from temperate rainforests in Victoria and Tasmania; Compactozetes bundjalung sp. nov., C. calderi sp. nov., C. duonodulus sp. nov., Sadocepheus remus sp. nov. (Compactozetidae) and Porrhotegaeus githabul sp. nov. (Porrhotegaeidae fam. nov.) from temperate and sub-tropical rainforests of the Great Dividing Range in central and northern New South Wales and southern Queensland, Porrhotegaeus catherinae sp. nov. from scalybark closed forest on Lord Howe Island, Eutegaeus odontatus sp. nov. and Compactozetes pirumorpha sp. nov. from moist upland forest on Norfolk Island and Neseutegaeus wardi sp. nov. and Atalotegaeus deficiens sp. nov. from tropical rainforest and moss forest in New Caledonia. Based on the predominantly Southern Hemisphere distribution of Eutegaeoidea, indicating strong Gondwanan affinities, and the morphology of adults and immatures, this taxon is treated as distinct from the Cepheoidea which has a distribution almost entirely within the Northern Hemisphere. Eutegaeoid species previously described from Australia (Eutegaeus soror P. Balogh, 1985, Atalotegaeus mensarosi J. & P. Balogh, 1983, Neseutegaeus monteithi J. & P. Balogh, 1983, Neoeutegaeus phyllophorus J. & P. Balogh, 1983 and Porrhotegaeus ornatus J. Balogh & Mahunka, 1966) are redescribed based on type material and new distribution records provided. Species have distribution patterns predominantly indicative of short-range endemics associated with remnant Gondwanan rainforest. Neseutegaeus monteithi is recombined with Atalotegaeus Luxton, 1988a. The definitions of genera and families of Eutegaeoidea are revised, and their relationships are reconsidered. Birotegaeus Luxton, 1988a and Pareutegaeus Woolley, 1965 are designated junior synonyms of Eutegaeus Berlese, 1916. Immatures are described for the genera Atalotegaeus, Eutegaeus, Neoeutegaeus Aoki, 1964 and Porrhotegaeus J. Balogh & Mahunka, 1966. Neoeutegaeidae fam. nov. is established for Neoeutegaeus Aoki, 1964 and Humerotegaeus gen. nov., Porrhotegaeidae fam. nov. for Porrhotegaeus and Bornebuschiidae fam. nov. for Bornebuschia Hammer, 1966 and Dicrotegaeus Luxton, 1988 which had previously been placed in Cerocepheidae or Compactozetidae. Eutegaeus aysenensis Ermilov, 2021 and E. queulatensis Ermilov, 2021 from Chile, are recombined with Atalotegaeus. A key is provided to the genera of the eight families of Eutegaeoidea, as recognised herein: Eutegaeidae, Neoeutegaeidae fam. nov., Cerocepheidae, Compactozetidae, Bornebuschiidae fam. nov., Pterozetidae and Porrhotegaeidae fam. nov.

Identification of coral disease within the high-latitude reef, Lord Howe Island Marine Park

Coral disease prevalence has significantly increased under a changing climate, impacting coral community structure and functionality. The impacts and ecology of coral diseases are unclear in most high-latitude reefs (coral reefs above 28° north and below 28° south). High-latitude locations are vulnerable to climate change; therefore, identifying diseases and developing region-specific baselines are important for local management. We report the first coral disease findings at the UNESCO World Heritage listed Lord Howe Island Marine Park (31.5°S, 159°E), the southernmost coral reef system. This study assessed coral disease prevalence during November 2018, March 2019 and October 2019. Surveys from three lagoonal reefs identified four coral diseases: white syndrome, skeletal eroding band, growth anomalies and endolithic hypermycosis impacting six coral taxa (Acropora, Isopora, Montipora, Pocillopora, Porites and Seriatopora). Overall, disease prevalence was 5 ± 1% and significantly differed between time and site. Disease prevalence was highest in November 2018 (10 ± 1%) and significantly lower during March 2019 (5 ± 1%), coinciding with a bleaching event. White syndrome was the most prevalent disease (4 ± 1%) with 83 colonies of six taxa affected, predominately Isopora. Acroporids recorded the highest disease susceptibility, with three of the four diseases observed. Documenting baseline coral disease prevalence and monitoring throughout a bleaching event assists our understanding of disease ecology dynamics under current climate change impacts at high-latitude reefs.

Protection and mortality of non-target terrestrial bird species during the eradication of rodents on Lord Howe Island

To eliminate the destructive impact of rodents on islands, conservation practitioners commonly use rodenticides to eradicate these pests. Frequently used rodenticides, such as brodifacoum, are non-specific. Consequently, non-target species may be susceptible to the poison. While mitigation actions to protect against unwanted impacts on non-target species are often included in eradication planning, such impacts are rarely measured or reported. In 2019, a rodent eradication program was implemented on Lord Howe Island to remove ship rats and house mice. To protect the island’s unique suite of endemic avian fauna, a comprehensive monitoring and mitigation plan was implemented. Following assessments of potential effects of baiting on island-species, two endemic species were taken into captive management during the eradication. To assess effects on other species, a total of 243 ha of bushland was searched over a 14-week period and an additional 190 ha was searched in the island’s settlement area for carcasses of non-targets. These surveys found that buff-banded rails suffered the highest level of mortality, but few carcasses of endemic species were found. The captive management program was successful with more than 95% of individuals that were taken into captivity being released at the end of the program. Post-eradication surveys of captive-managed species have shown that the endemic woodhen population has increased by nearly five-fold on pre-eradication levels and that endemic currawong numbers have also increased. Surveys of other bush birds have found higher numbers for most species and shows that pre-eradication assessments of these species being at lower risk were appropriate.

New branched Porolithon species (Corallinales, Rhodophyta) from the Great Barrier Reef, Coral Sea, andLord Howe Island.

Porolithon is one of the most ecologically important genera of tropical and subtropical crustose (non-geniculate) coralline algae growing abundantly along the shallow margins of coral reefs and functioning to cement reef frameworks. Thalli of branched, fruticose Porolithon specimens from the Indo-Pacific Ocean traditionally have been called P. gardineri, while massive, columnar forms have been called P. craspedium. Sequence comparisons of the rbcL gene both from type specimens of P. gardineri and P. craspedium and from field-collected specimens demonstrate that neither species is present in east Australia and instead resolve into four unique genetic lineages. Porolithon howensis sp. nov. forms columnar protuberances and loosely attached margins and occurs predominantly at Lord Howe Island; P. lobulatum sp. nov. has fruticose to clavate forms and free margins that are lobed and occurs in the Coral Sea and on the Great Barrier Reef (GBR); P. parvulum sp. nov. has short (<2 cm), unbranched protuberances and attached margins and is restricted to the central and southern GBR; and P. pinnaculum sp. nov. has a mountain-like, columnar morphology and occurs on oceanic Coral Sea reefs. A rbcL gene sequence of the isotype of P. castellum demonstrates it is a different species from other columnar species. In addition to the diagnostic rbcL and psbA marker sequences, the four new species may be distinguished by a combination of features including thallus growth form, margin shape (attached or unattached), and medullary system (coaxial or plumose). Porolithon species, because of their ecological importance and sensitivity to ocean acidification, need urgent documentation of their taxonomic diversity.

Drone-Based Monitoring to Remotely Assess a Beach Nourishment Program on Lord Howe Island

Beach nourishment is a soft engineering technique that is used to combat coastal erosion. To assess the efficacy of a beach nourishment program on the northwest coast of Lord Howe Island, remotely coordinated drone-based monitoring was undertaken at Lagoon Beach. Specifically, hypotheses were tested that beach nourishment could increase the dune height and the width of the beach where the sand was translocated but would not have any long-term impacts on other parts of the beach. During the beach nourishment program, sand was translocated from the north end to the south end of Lagoon Beach, where it was deposited over 2800 m2. Lagoon Beach was monitored using a time series of 3D orthomosaics (2019–2021) based on orthorectified drone imagery. The data were then analysed using a robust before-after-control-impact (BACI) experimental design. Initially, a fully automated drone mapping program and permanent ground control points were set up. After this, a local drone pilot facilitated automated drone mapping for the subsequent times of sampling and transferred data to mainland researchers. As well as being more cost-effective, this approach allowed data collection to continue during Island closures due to the COVID-19 pandemic. After sand translocation, the south end of Lagoon Beach had a lower dune with more vegetation and a more expansive beach with a gentler slope than the prior arrangement. Overall, drone monitoring demonstrated the efficacy of the beach nourishment program on Lord Howe Island and highlighted the capacity for drones to deliver cost-effective data in locations that were difficult for researchers to access.

A taxonomic synopsis of unifoliolate continental African Vepris (Rutaceae)

SummaryDescriptions and illustrations are presented for three new species to science, Vepris udzungwa Cheek, V. lukei Cheek (both Udzungwa Mts, Tanzania), and V. robertsoniae Q.Luke &amp; Cheek (SE Kenyan kaya forests), in the context of a synoptic taxonomic revision and with an identification key to all the known unifoliolate taxa of Vepris in continental Africa. The new species are described and illustrated, while the remaining 10 taxa are given skeletal taxonomic treatments (lacking descriptions). One widespread species in montane eastern Africa is renamed as V. simplex Cheek because its previous name, V. simplicifolia (Engl.) Mziray, is predated by V. simplicifolia Endl. (basionym of Sarcomelicope simplicifolia (Endl.) T.G.Hartley, a widespread species of Australia, Lord Howe and Norfolk Islands, and of New Caledonia). The new combination Vepris hanangensis var. unifoliolata (Kokwaro) Cheek is made. Full or provisional conservation assessments are presented for all species using the IUCN 2012 standard. Of the 13 taxa, nine are considered threatened or near threatened, of which one is Near Threatened, three are Vulnerable, two Endangered, and three Critically Endangered, with two of the latter, both of the Uluguru Mts of Tanzania, possibly extinct globally, although not yet assessed on the IUCN Red List.