ORCID Profile
0000-0002-6918-8959
Current Organisation
University of Otago
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Research Topics
In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Top 5 Research Topics
ANZSRC Field of Research (FoR)
Evolutionary Impacts of Climate Change | Environmental Science and Management | Conservation and Biodiversity | Biogeography and Phylogeography | Other Biological Sciences | Environmental Management | Invasive Species Ecology | Evolutionary Biology | Population, Ecological and Evolutionary Genetics | Climate Change Processes | Global Change Biology
ANZSRC Socio-Economic Objective (SEO)
Antarctic and Sub-Antarctic Flora, Fauna and Biodiversity | Effects of Climate Change and Variability on Antarctic and Sub-Antarctic Environments (excl. Social Impacts) | Ecosystem Adaptation to Climate Change | Ecosystem Assessment and Management of Antarctic and Sub-Antarctic Environments | Environmental Policy, Legislation and Standards not elsewhere classified | Expanding Knowledge in the Biological Sciences | Flora, Fauna and Biodiversity at Regional or Larger Scales |
Related Links
Publications
The changing form of Antarctic biodiversity
Publisher: Springer Science and Business Media LLC
Date: 06-2015
DOI: 10.1038/NATURE14505
Abstract: Antarctic bio ersity is much more extensive, ecologically erse and biogeographically structured than previously thought. Understanding of how this ersity is distributed in marine and terrestrial systems, the mechanisms underlying its spatial variation, and the significance of the microbiota is growing rapidly. Broadly recognizable drivers of ersity variation include energy availability and historical refugia. The impacts of local human activities and global environmental change nonetheless pose challenges to the current and future understanding of Antarctic bio ersity. Life in the Antarctic and the Southern Ocean is surprisingly rich, and as much at risk from environmental change as it is elsewhere.
Long-term changes in polychaete assemblages of Botany Bay (NSW, Australia) following a dredging event
Publisher: Elsevier BV
Date: 09-2006
DOI: 10.1016/J.MARPOLBUL.2005.12.016
Abstract: The long-term effects of marine aggregate dredging on near-shore benthic assemblages are still largely unknown, despite a global increase in demand for, and extraction of, marine aggregates. This study assessed the state of recovery of polychaete assemblages in Botany Bay, temperate NSW, Australia, at sites dredged for aggregate material more than 10 years previously. Sedimentary and faunal s les were collected from impact sites in Botany Bay, and from reference sites in nearby Pittwater estuary. This study was based on, and included data from, a study conducted by the Australian Museum at the same sites in the 2 years following cessation of dredging. Abundance, species richness and evenness of polychaetes, as well as overall polychaete assemblage structure, were compared between localities over time.
Dispersal Biogeography
Publisher: Elsevier
Date: 2016
Genome‐wide SNP data reveal improved evidence for Antarctic glacial refugia and dispersal of terrestrial invertebrates
Publisher: Wiley
Date: 28-10-2019
DOI: 10.1111/MEC.15269
Abstract: Antarctica is isolated, surrounded by the Southern Ocean and has experienced extreme environmental conditions for millions of years, including during recent Pleistocene glacial maxima. How Antarctic terrestrial species might have survived these glaciations has been a topic of intense interest, yet many questions remain unanswered, particularly for Antarctica's invertebrate fauna. We examine whether genetic data from a widespread group of terrestrial invertebrates, springtails (Collembola, Isotomidae) of the genus Cryptopygus, show evidence for long-term survival in glacial refugia along the Antarctic Peninsula. We use genome-wide SNP analyses (via genotyping-by-sequencing, GBS) and mitochondrial data to examine population ersity and differentiation across more than 20 sites spanning >950 km on the Peninsula, and from islands both close to the Peninsula and up to ~1,900 km away. Population structure analysis indicates the presence of strong local clusters of ersity, and we infer that patterns represent a complex interplay of isolation in local refugia coupled with occasional successful long-distance dispersal events. We identified wind and degree days as significant environmental drivers of genetic ersity, with windier and warmer sites hosting higher ersity. Thus, we infer that refugial areas along the Antarctic Peninsula have allowed populations of indigenous springtails to survive in situ throughout glacial periods. Despite the difficulties of dispersal in cold, desiccating conditions, Cryptopygus springtails on the Peninsula appear to have achieved multiple long-distance colonization events, most likely through wind-related dispersal events.
The founder space race: A reply to Buckley et al.
Publisher: Elsevier BV
Date: 04-2013
SNP analyses reveal a diverse pool of potential colonists to earthquake‐uplifted coastlines
Publisher: Wiley
Date: 04-12-2019
DOI: 10.1111/MEC.15303
Abstract: In species that form dense populations, major disturbance events are expected to increase the chance of establishment for immigrant lineages. Real-time tests of the impact of disturbance on patterns of genetic structure are, however, scarce. Central to testing these concepts is determining the pool of potential immigrants dispersing into a disturbed area. In 2016, a 7.8 magnitude earthquake occurred on the South Island of New Zealand. Affecting approximately 100 km of coastline, this quake caused extensive uplift (several metres high), extirpating many intertidal populations, including keystone intertidal kelp species. Following the uplift, we set out to determine the geographic origins of detached kelp specimens which rafted into the disturbed zone. Specifically, we used genotyping-by-sequencing (GBS) approaches to compare beach-cast southern bull-kelp (Durvillaea antarctica and Durvillaea poha) s les to established populations throughout the species' ranges, and thus infer the geographic origins of potential colonists reaching the disturbed coast. Our findings revealed an ongoing supply of erse lineages dispersing to the newly uplifted coastline, suggesting potential for establishment of "exotic" lineages following disturbance. Furthermore, we found that some drifting in iduals of each species came from far-distant regions, some >1,200 km away. These results show that erse lineages - in many cases from very distant sources - can compete for new space in the wake of an exceptional disturbance event, illustrating the potential of long-distance dispersal as a key mechanism for reassembly of coastal ecosystems. Furthermore, our findings demonstrate that high-resolution genomic baselines can be used to robustly assign the provenance of dispersing in iduals.
Did interaction between human pressure and Little Ice Age drive biological turnover in New Zealand?
Publisher: Wiley
Date: 17-04-2017
DOI: 10.1111/JBI.12991
Climate-driven changes to ocean circulation and their inferred impacts on marine dispersal patterns
Publisher: Wiley
Date: 02-05-2016
DOI: 10.1111/GEB.12456
Poleward bound: Biological impacts of Southern Hemisphere glaciation
Publisher: Elsevier BV
Date: 08-2012
DOI: 10.1016/J.TREE.2012.04.011
Abstract: Postglacial recolonisation patterns are well documented for the Northern Hemisphere biota, but comparable processes in the Southern Hemisphere have only recently been examined. In the largely terrestrial Northern Hemisphere, recession of ice after the Last Glacial Maximum (LGM) allowed various taxa, including slow-moving terrestrial species, to migrate poleward. By contrast, the Southern Hemisphere polar region is completely ringed by ocean, and recolonisation of Antarctica and the sub-Antarctic islands has thus presented considerable challenges. Although a few highly dispersive marine species have been able to recolonise postglacially, most surviving high-latitude taxa appear to have persisted throughout glacial maxima in local refugia. These contrasting patterns highlight the importance of habitat continuity in facilitating biological range shifts in response to climate change.
Holdfast coalescence between buoyant and non-buoyant seaweeds
Publisher: CSIRO Publishing
Date: 09-2021
DOI: 10.1071/MF21016
Abstract: Some inherently poorly dispersive marine species have surprisingly large or patchy distributions that might be explained by rafting or ‘hitchhiking’. The genus Durvillaea (southern bull kelp) includes both highly buoyant and entirely non-buoyant species. Several of the non-buoyant, poorly dispersive species have puzzling distributions that are hard to explain without invoking long-distance dispersal hypotheses. We propose that these non-dispersive species of Durvillaea may be able to hitchhike with buoyant, dispersive congenerics by interspecific holdfast coalescence. Although many cases of intraspecific holdfast coalescence have been recorded, interspecific coalescence is less well documented. To determine whether interspecific holdfast coalescence occurs in Durvillaea, a rock platform on the south-east coast of New Zealand was surveyed, revealing multiple ex les of naturally occurring interspecific holdfast coalescence. S les were taken from coalesced holdfasts and genetic sequencing was performed to attempt to gauge whether tissue from both species was mixed throughout the holdfast or remained discrete. The discovery of interspecific coalescence between non-buoyant and buoyant Durvillaea raises the possibility that non-buoyant seaweeds may disperse with buoyant congenerics by rafting, and could help explain the distributions of various other non-buoyant macroalgae.
Rafting dispersal in a brooding southern sea star (Asteroidea : Anasterias)
Publisher: CSIRO Publishing
Date: 2018
DOI: 10.1071/IS17037
Abstract: Marine biogeographers have long speculated that macroalgal rafting presents a dispersal mechanism for brooding marine invertebrates of the Southern Ocean, but few direct observations of rafting by echinoderm taxa have been documented. Here we report rafting of the brooding benthic sea star Anasterias suteri, along with two mollusc taxa (Onithochiton neglectus – also a brooder – and Cantharidus roseus), on detached bull-kelp Durvillaea antarctica in Foveaux Strait, southern New Zealand. The rafting journey, intercepted at sea, likely lasted for 2–3 weeks and may have covered several hundred kilometres. We use DNA sequences, together with meteorological and prevailing oceanographic data, to infer the likely Fiordland (mainland) origins of the raft and its epifauna. This rafting dispersal mechanism provides an explanation for the broad (circum-subantarctic) but disjunct distribution of brooding Anasterias populations, and for the genetic connectivity observed between their populations.
Rafting dispersal constrained by an oceanographic boundary
Publisher: Inter-Research Science Center
Date: 31-03-2014
DOI: 10.3354/MEPS10675
Antarctica’s ecological isolation will be broken by storm-driven dispersal and warming
Publisher: Springer Science and Business Media LLC
Date: 16-07-2018
Breaking down the barrier: dispersal across the Antarctic Polar Front
Publisher: Wiley
Date: 23-05-2016
DOI: 10.1111/ECOG.02449
Organellar genomes of giant kelp from the southern hemisphere
Publisher: Informa UK Limited
Date: 28-03-2023
Report Writing Assessment for Postgraduate Students: Lecturer’s Perspective
Publisher: Springer International Publishing
Date: 2019
Rapid winter warming could disrupt coastal marine fish community structure
Publisher: Springer Science and Business Media LLC
Date: 13-07-2020
Priority effects can lead to underestimation of dispersal and invasion potential
Publisher: Springer Science and Business Media LLC
Date: 28-05-2015
Seaweed Phylogeography
Publisher: Springer Netherlands
Date: 2016
Women in biogeography
Publisher: Wiley
Date: 26-07-2021
DOI: 10.1111/JBI.14223
Abstract: Despite increasing awareness of issues affecting inclusivity, equity and ersity, change has been slow in science and academia, and gender disparities remain significant. Biogeography has not escaped this pattern. Here, we present a virtual issue compiling some of the most cited papers led by women that have been published in the Journal of Biogeography since 2009 in an effort to equalize visibility of women's influential work. We summarize leading gender disparities and their potential underlying causes, and present our motivation and methodology in compiling this issue. We further provide a blog, website and social media links to highlight the research of the authors whose work is showcased here. Highlighting influential contributions by women biogeographers is a small step towards equalizing visibility across genders. We hope that this virtual issue will also contribute in some way to creating a greater sense of belonging for women biogeographers.
Can a terrestrial ectoparasite disperse with its marine host?
Publisher: University of Chicago Press
Date: 03-2019
DOI: 10.1086/701726
Abstract: One of the most extreme ex les of parasite adaptation comes from terrestrial ectoparasites exploiting marine hosts. Despite the ubiquity of such ectoparasitism and its ecological and evolutionary importance, investigations of the responses of ectoparasites to conditions encountered on their hosts are rare. In the case of penguins and their ticks, current understanding suggests that ticks freely parasitize their hosts on land but are incapable of surviving extended oceanic journeys. We examined this conjecture by assessing the physiological capacity of little penguin ticks to endure at-sea foraging and dispersal events of their hosts. Survival in penguins ticks was not significantly compromised by exposure to depths commonly associated with host es (40 and 60 m), repeated seawater exposure relevant to the most common (30 s) and longest (120 s) recorded host es, or extended (48 h) exposure to seawater. Mean (±SD) closed-phase durations in adult and nymphal ticks exhibiting discontinuous gas exchange ( 339 ± 237 and 240 ± 295 s, respectively) exceeded that of the maximum recorded host e duration (120 s). Normoxic-anoxic-normoxic respirometry also confirmed spiracle closure. Mean metabolic rates ( 0.354 ± 0.220 and 4.853 ± 4.930 μL/h at 25°C for unfed and fed adult females, respectively) were significantly influenced by temperature optimal and LT
Australian penguin ticks screened for novel Borrelia species
Publisher: Elsevier BV
Date: 02-2018
DOI: 10.1016/J.TTBDIS.2017.12.007
Abstract: Lyme borreliosis (or Lyme Disease) is an emerging threat to human health in the Northern Hemisphere caused by tick-borne bacteria from the Borrelia burgdorferi sensu lato (Bbsl) complex. Seabirds are important reservoir hosts of some members of the Bbsl complex in the Northern Hemisphere, and some evidence suggests this may be true of penguins in the Southern Hemisphere. While the Bbsl complex has not been detected in Australia, a novel Borrelia species ('Candidatus Borrelia tachyglossi') was recently sequenced from native ticks (Ixodes holocyclus and Bothriocroton concolor) parasitising echidnas (Tachyglossus aculeatus), suggesting unidentified borreliae may be circulating amongst native wildlife and their ticks. In the present study, we investigated whether ticks parasitising little penguins (Eudyptula novaehollandiae) harbour native or introduced Borrelia bacteria. We chose this penguin species because it is heavily exploited by ticks during the breeding season, lives in close proximity to other potential reservoir hosts (including native wildlife and migratory seabirds), and is known to be infected with other tick-borne pathogens (Babesia). We screened over 230 penguin ticks (Ixodes spp.) from colonies in south-eastern Australia, and found no evidence of Borrelia DNA. The apparent absence or rarity of the bacterium in south-eastern Australia has important implications for identifying potential tick-borne pathogens in an understudied region.
Genetic impacts of physical disturbance processes in coastal marine ecosystems
Publisher: Wiley
Date: 17-07-2022
DOI: 10.1111/JBI.14464
Abstract: Coastal habitats are among the most dynamic environments on earth and are highly vulnerable to large‐scale physical disturbance. Genetic studies of nearshore marine species are revealing long‐lasting signatures of major coastal disturbance events. We synthesize emerging data to highlight how physical perturbations can impact the phylogeographic patterns of coastal populations. Coastal marine and estuarine taxa. Coastal regions around the globe. We synthesize coastal genetic and genomic literature, focussing particularly on the phylogeographic consequences of natural disturbance events including uplift, tsunami, hurricanes, glaciations and sea‐level fluctuations. We focus on studies with clear physical analytical frameworks constrained by abiotic data. Tectonic and atmospheric disruptions can be considered shot‐term events with major impacts on populations adjacent to the centre of disturbance, typically resulting in the evolution of shallow phylogeographic patterns. Long‐lived climate‐driven disturbances such as glaciations, however, operate over vast geographic scales and often drive deep evolutionary patterns in affected populations. We show that studies using genome‐wide data could better identify fine‐scale signatures of both past and contemporary habitat perturbations. Recent data reveal the interplay between physical upheaval and coastal phylogeography, indicating that disturbance can affect ersity, connectivity and demography of coastal populations. The interplay between long‐lived large‐scale disturbance and species‐specific biotic traits has shaped deep phylogeographic patterns of coastal taxa. Additionally, it could be argued that, at least for some regions, short‐term disturbance is the ‘rule’ rather than the ‘exception’, and thus, represents a key driver of coastal genetic patterns in disturbance prone coastal regions. Geo‐genomic approaches that combine genome‐wide data with explicit habitat models or disturbance history information have been particularly successful in explaining the drivers of coastal evolutionary change. We argue that future integration of genomic and physical data will be crucial for tracing evolutionary trends in fast‐changing marine environments.
Change in Southern Hemisphere Intertidal Communities Through Climate Cycles: The Role of Dispersing Algae
Publisher: Springer Netherlands
Date: 2016
Molecular evidence supports coastal dispersal among estuaries for two benthic marine worm (Nephtyidae) species in southeastern Australia
Publisher: Springer Science and Business Media LLC
Date: 05-05-2015
Population genomic analysis reveals genetic structure and thermal-tolerant genotypes in remnant Tasmanian giant kelp populations
Publisher: Cold Spring Harbor Laboratory
Date: 10-10-2023
GENETIC AND MORPHOLOGICAL ANALYSES OF THE SOUTHERN BULL KELP DURVILLAEA ANTARCTICA (PHAEOPHYCEAE: DURVILLAEALES) IN NEW ZEALAND REVEAL CRYPTIC SPECIES1
Publisher: Wiley
Date: 04-2009
DOI: 10.1111/J.1529-8817.2009.00658.X
Abstract: Many macroalgae exhibit considerable intraspecific morphological variation, but whether such variation reflects phenotypic plasticity or underlying genetic differences is often poorly understood. We quantified both morphological and genetic variation of 96 plants from seven field sites across eastern South Island, New Zealand, to assess genetic differences between morphotypes of the southern bull kelp Durvillaea antarctica (Cham.) Har. Consistent DNA sequence differentiation across mitochondrial, plastid, and nuclear loci was correlated with two broadly sympatric morphotypes: "cape" and "thonged." These ecologically, morphologically, and genetically distinct bull-kelp lineages were previously considered to be environmentally determined phenotypes with no underlying genetic basis. Interestingly, the sheltered "cape" lineage appears essentially genetically uniform across its South Island range, whereas the exposed "thonged" lineage exhibits marked phylogeographic structure across its range. Results suggest that D. antarctica in New Zealand comprises two reproductively isolated species.
Multigene phylogeny of the southern bull-kelp genus Durvillaea (Phaeophyceae: Fucales)
Publisher: Elsevier BV
Date: 12-2010
DOI: 10.1016/J.YMPEV.2010.10.011
Abstract: Durvillaea (southern bull-kelp) is an economically and ecologically important brown algal genus that dominates many exposed, rocky coasts in the cold-temperate Southern Hemisphere. Of its five currently-recognized species, four are non-buoyant and restricted to the south-western Pacific, whereas one is both buoyant and widely distributed. Durvillaea has had an unsettled taxonomic history. Although its position within the brown algae (Phaeophyceae) has now been largely resolved through the use of molecular techniques, the taxonomic status of several Durvillaea species/morphotypes remains unresolved. Previous molecular phylogenetic studies of phaeophycean taxa have included few Durvillaea s les, and have consequently paid little or no attention to variation within this genus. The current study presents phylogenetic analyses of four genetic markers (mitchondrial: COI chloroplast: rbcL and nuclear: 18S and 28S) to resolve phylogenetic relationships within Durvillaea. Results support the monophyly of solid-bladed taxa D. willana, D. potatorum, and D. sp. A (an undescribed species from the Antipodes Islands), whereas the widespread, buoyant D. antarctica is paraphyletic, with solid-bladed D.chathamensis placed sister to a D. antarctica clade from northern NZ but within D. antarctica sensu lato. The phylogenetic and ecological ersity detected within D. antarctica indicate that it is a species complex of five deeply ergent clades. Under a phylogenetic species concept, Durvillaea can be interpreted as a complex of nine distinct evolutionary lineages, only one of which has an intercontinental distribution ('subantarctic'D. antarctica).
DNA Extraction Techniques for Genomic Analyses of Macroalgae
Publisher: Springer Netherlands
Date: 2016
Obesity Is Associated With Low NAD+/SIRT Pathway Expression in Adipose Tissue of BMI-Discordant Monozygotic Twins
Publisher: The Endocrine Society
Date: 2016
DOI: 10.1210/JC.2015-3095
Abstract: Sirtuins (SIRTs) regulate cellular metabolism and mitochondrial function according to the energy state of the cell reflected by NAD(+) levels. Our aim was to determine whether expressions of SIRTs and NAD(+) biosynthesis genes are affected by acquired obesity and how possible alterations are connected with metabolic dysfunction while controlling for genetic and familial factors. We studied a cross-sectional s le of 40 healthy pairs of monozygotic twins, including 26 pairs who were discordant for body mass index (within-pair difference > 3 kg/m(2)), from the FinnTwin12 and FinnTwin16 cohorts. Subcutaneous adipose tissue (SAT) transcriptomics was analyzed by using Affymetrix U133 Plus 2.0 chips, total SAT (poly-ADP) ribose polymerase (PARP) activity by an ELISA kit, body composition by dual-energy x-ray absorptiometry and magnetic resonance imaging/spectroscopy, and insulin sensitivity by an oral glucose tolerance test. SIRT1, SIRT3, SIRT5, NAMPT, NMNAT2, NMNAT3, and NRK1 expressions were significantly down-regulated and the activity of main cellular NAD(+) consumers, PARPs, trended to be higher in the SAT of heavier co-twins of body mass index-discordant pairs. Controlling for twin-shared factors, SIRT1, SIRT3, NAMPT, NMNAT3, and NRK1 were significantly negatively correlated with adiposity, SIRT1, SIRT5, NMNAT2, NMNAT3, and NRK1 were negatively correlated with inflammation, and SIRT1 and SIRT5 were positively correlated with insulin sensitivity. Expressions of genes involved in mitochondrial unfolded protein response were also significantly down-regulated in the heavier co-twins. Our data highlight a strong relationship of reduced NAD(+)/SIRT pathway expression with acquired obesity, inflammation, insulin resistance, and impaired mitochondrial protein homeostasis in SAT.
Asymmetric dispersal of southern bull-kelp (Durvillaea antarctica) adults in coastal New Zealand: Testing an oceanographic hypothesis
Publisher: Wiley
Date: 28-09-2010
Northward range extension for Durvillaea poha bull kelp: Response to tectonic disturbance?
Publisher: Wiley
Date: 26-05-2021
DOI: 10.1111/JPY.13179
Abstract: Understanding the forces that shape species distributions is increasingly important in a fast‐changing world. Although major disturbance events can adversely affect natural populations, they can also present new opportunities, for ex le by opening up habitat for colonization by other lineages. Following extensive geographic s ling, we use genomic data to infer a range extension following disturbance for an ecologically important intertidal macroalgal species. Specifically, we genotyped 288 southern bull kelp ( Durvillaea ) plants from 28 localities across central New Zealand. All specimens from the North Island were expected to be D. antarctica , but unexpectedly 10 s les from four sites were identified as D. poha . Extensive s ling from the northern South Island (105 s les at five locations) confirmed the absence of D. poha north of the Kaikōura Peninsula. The North Island specimens of D. poha therefore reveal a biogeographic disjunction, some 150 km northeast of the nearest (South Island) population of this species. Based on strong geographic correspondence between these North Island s les and historic disturbance, we infer that tectonic upheaval, particularly earthquake‐generated landslides, likely extirpated local D. antarctica and created an opportunity for a northward range expansion event by D. poha . Close phylogenomic relationships between this new North Island population and South Island s les support a geologically recent northward expansion, rather than a deeper evolutionary origin. These findings indicate the potential of large‐scale disturbances to facilitate sudden biogeographic range expansions, and they emphasize the ability of genomic analyses with fine‐scale s ling to reveal long‐lasting signatures of past disturbance, dispersal, and colonization.
How disturbance and dispersal influence intraspecific structure
Publisher: Wiley
Date: 05-12-2018
Genetic Affinities between Trans-Oceanic Populations of Non-Buoyant Macroalgae in the High Latitudes of the Southern Hemisphere
Publisher: Public Library of Science (PLoS)
Date: 22-07-2013
Differential Clinicopathological Risk and Prognosis of Major Papillary Thyroid Cancer Variants
Publisher: The Endocrine Society
Date: 2016
DOI: 10.1210/JC.2015-2917
The Role of Floating Plants in Dispersal of Biota Across Habitats and Ecosystems
Publisher: CRC Press
Date: 26-08-2016
Sedimentology of a wreck: The Rainbow Warrior revisited
Publisher: Elsevier BV
Date: 11-2011
DOI: 10.1016/J.MARPOLBUL.2011.08.028
Abstract: The wreck of the Rainbow Warrior, a 40-m ship sunk on 12 December 1987 in Matauri Bay (34° 59' S, 173° 56' E), Cavalli Islands, northeastern New Zealand, offers an opportunity to investigate the impact of artificial substrate on temperate carbonate sedimentation. Surface sediment s les showed no significant textural or compositional difference between sediments near the wreck and those far from it. The large and erse carbonate-producing community resident on the wreck (dominated by bryozoans, corals and sponges) has not had a measurable influence on adjacent bottom sediments (dominated by bivalves and barnacles), even after 21 years. It is likely that carbonate production on the Rainbow Warrior is insufficient to leave any sedimentary record over the potential lifetime of the wreck on the seafloor, which informs our understanding of the long-term impacts of shipwrecks (and other artificial substrata) on the local benthic environment in shallow temperate ecosystems.
Phylogeographic Structure in Penguin Ticks across an Ocean Basin Indicates Allopatric Divergence and Rare Trans-Oceanic Dispersal
Publisher: Public Library of Science (PLoS)
Date: 17-06-2015
Pathogen inferred to have dispersed thousands of kilometres at sea, infecting multiple keystone kelp species
Publisher: Springer Science and Business Media LLC
Date: 18-03-2021
DOI: 10.1007/S00227-021-03853-8
Abstract: Protistan pathogens have been found to infect populations of some large brown macroalgae. Infection could reduce the ability of macroalgae to withstand hydrodynamic pressures through weakening tissues and reducing flexibility. Widespread mortality of macroalgae if disease outbreaks were to occur could have important flow-on consequences for bio ersity and ecosystem function. Recent discoveries of the protistan pathogen Maullinia infecting the ecologically keystone southern bull kelp Durvillaea in Chile, Australia, and on Marion Island, raise the possibility that this pathogen is dispersing across ocean basins with buoyant hosts. To determine whether Maullinia also infects southern bull kelp in New Zealand, s les of gall-like tissue from Durvillaea antarctica , D. poha , and D. willana were collected from intertidal sites, and genetic analyses (sequencing of partial 18S rRNA) carried out. Maullinia infections were detected in all three species of Durvillaea . Phylogenetic analyses show a close relationship of New Zealand Maullinia to M. braseltonii previously detected in Chile and on Marion Island. Based on its genetic similarity to distant lineages and its presence on buoyant hosts that have been shown to drift long distances at seas, we infer that Maullinia has dispersed across the Southern Ocean through rafting of infected bull kelp. Understanding the capacity of pathogens to disperse across oceans is critical part of forecasting and managing ecosystem responses to environmental change.
Penguin ectoparasite panmixia suggests extensive host movement within a colony
Publisher: Oxford University Press (OUP)
Date: 07-2018
DOI: 10.1642/AUK-17-226.1
Genotyping‐by‐sequencing for biogeography
Publisher: Wiley
Date: 07-11-2022
DOI: 10.1111/JBI.14516
Abstract: Genotyping‐by‐sequencing (GBS) and similar reduced‐representation sequencing methods, such as restriction site‐associated DNA sequencing (RADseq), have been revolutionary for genetic analyses in biogeography. However, navigating the many different methodological and analytical approaches and numerous sources of potential error can be overwhelming. We provide an overview of key considerations for biogeographical research using GBS, from s le design through data filtering to the sharing of data, which should particularly assist new users. All taxa. Worldwide. We review recent advances for GBS and compare differences among GBS methods and analytical approaches. We highlight the concerns most relevant for biogeographical research, and emphasise practical limitations for studies on non‐model organisms. GBS methods vary substantially and recent literature demonstrates the need for careful study design and data filtering relevant to the study organism and hypothesis under investigation. Biogeographical research using non‐model organisms or long‐term s ling are likely to face some practical limitations compared to ideal GBS study designs. The methodological information recorded in published manuscripts often varies. We outline a general framework for planning and undertaking biogeographical research using GBS. GBS and similar approaches have grown rapidly in popularity for biogeographical research. Evaluating, recording and justifying decisions throughout a GBS workflow—across s ling, library preparation and sequencing, identifying and filtering s les and loci, biogeographical analyses, and sharing data—is crucial for improving scientific reproducibility and compatibility among GBS datasets. This review outlines ways to improve and simplify GBS research, thereby enhancing our capacity to use genomic data to address broad‐scale biogeographical questions.
Kelp genes reveal effects of subantarctic sea ice during the Last Glacial Maximum
Publisher: Proceedings of the National Academy of Sciences
Date: 03-03-2009
Abstract: The end of the Last Glacial Maximum (LGM) dramatically reshaped temperate ecosystems, with many species moving poleward as temperatures rose and ice receded. Whereas reinvading terrestrial taxa tracked melting glaciers, marine biota recolonized ocean habitats freed by retreating sea ice. The extent of sea ice in the Southern Hemisphere during the LGM has, however, yet to be fully resolved, with most palaeogeographic studies suggesting only minimal or patchy ice cover in subantarctic waters. Here, through population genetic analyses of the widespread Southern Bull Kelp ( Durvillaea antarctica ), we present evidence for persistent ice scour affecting subantarctic islands during the LGM. Using mitochondrial and chloroplast genetic markers (COI rbc L) to genetically characterize some 300 kelp s les from 45 Southern Ocean localities, we reveal a remarkable pattern of recent recolonization in the subantarctic. Specifically, in contrast to the marked phylogeographic structure observed across coastal New Zealand and Chile (10- to 100-km scales), subantarctic s les show striking genetic homogeneity over vast distances (10,000-km scales), with a single widespread haplotype observed for each marker. From these results, we suggest that sea ice expanded further and ice scour during the LGM impacted shallow-water subantarctic marine ecosystems more extensively than previously suggested.
Structure function tensor scaling in the logarithmic region derived from the attached eddy model of wall-bounded turbulent flows
Publisher: American Physical Society (APS)
Date: 05-06-2017
Parallel recolonizations generate distinct genomic sectors in kelp following high‐magnitude earthquake disturbance
Publisher: Wiley
Date: 21-06-2022
DOI: 10.1111/MEC.16535
Abstract: Large‐scale disturbance events have the potential to drastically reshape bio ersity patterns. Notably, newly vacant habitat space cleared by disturbance can be colonized by multiple lineages, which can lead to the evolution of distinct spatial “sectors” of genetic ersity within a species. We test for disturbance‐driven sectoring of genetic ersity in intertidal southern bull kelp, Durvillaea antarctica (Chamisso) Hariot, following the high‐magnitude 1855 Wairarapa earthquake in New Zealand. Specifically, we use genotyping‐by‐sequencing (GBS) to analyse fine‐scale population structure across the uplift zone and apply machine learning to assess the fit of alternative recolonizaton models. Our analysis reveals that specimens from the uplift zone carry distinctive genomic signatures potentially linked to post‐earthquake recolonization processes. Specifically, our analysis identifies two parapatric spatial‐genomic sectors of D. antarctica at Turakirae Head, which experienced the most dramatic uplift. Based on phylogeographical modelling, we infer that bull kelp in the Wellington region was probably a source for recolonization of the heavily uplifted Turakirae Head coastline, via two parallel, eastward recolonization events. By identifying multiple parapatric genotypic sectors within a recently recolonized coastal region, the current study provides support for the hypothesis that competing lineage expansions can generate striking spatial structuring of genetic ersity, even in highly dispersive taxa.
Journal of Biogeography Innovation Awards, 2023
Publisher: Wiley
Date: 05-06-2023
DOI: 10.1111/JBI.14630
Association Between BRAF V600E Mutation and Recurrence of Papillary Thyroid Cancer
Publisher: American Society of Clinical Oncology (ASCO)
Date: 2015
Abstract: To investigate the prognostic value of BRAF V600E mutation for the recurrence of papillary thyroid cancer (PTC). This was a retrospective multicenter study of the relationship between BRAF V600E mutation and recurrence of PTC in 2,099 patients (1,615 women and 484 men), with a median age of 45 years (interquartile range [IQR], 34 to 58 years) and a median follow-up time of 36 months (IQR, 14 to 75 months). The overall BRAF V600E mutation prevalence was 48.5% (1,017 of 2,099). PTC recurrence occurred in 20.9% (213 of 1,017) of BRAF V600E mutation–positive and 11.6% (125 of 1,082) of BRAF V600E mutation–negative patients. Recurrence rates were 47.71 (95% CI, 41.72 to 54.57) versus 26.03 (95% CI, 21.85 to 31.02) per 1,000 person-years in BRAF mutation–positive versus –negative patients (P .001), with a hazard ratio (HR) of 1.82 (95% CI, 1.46 to 2.28), which remained significant in a multivariable model adjusting for patient sex and age at diagnosis, medical center, and various conventional pathologic factors. Significant association between BRAF mutation and PTC recurrence was also found in patients with conventionally low-risk disease stage I or II and micro-PTC and within various subtypes of PTC. For ex le, in BRAF mutation–positive versus –negative follicular-variant PTC, recurrence occurred in 21.3% (19 of 89) and 7.0% (24 of 342) of patients, respectively, with recurrence rates of 53.84 (95% CI, 34.34 to 84.40) versus 19.47 (95% CI, 13.05 to 29.04) per 1,000 person-years (P .001) and an HR of 3.20 (95% CI, 1.46 to 7.02) after adjustment for clinicopathologic factors. BRAF mutation was associated with poorer recurrence-free probability in Kaplan-Meier survival analyses in various clinicopathologic categories. This large multicenter study demonstrates an independent prognostic value of BRAF V600E mutation for PTC recurrence in various clinicopathologic categories.
Evidence of plant and animal communities at exposed and subglacial (cave) geothermal sites in Antarctica
Publisher: Springer Science and Business Media LLC
Date: 17-08-2017
Durvillaea poha sp. nov. (Fucales, Phaeophyceae): a buoyant southern bull-kelp species endemic to New Zealand
Publisher: Informa UK Limited
Date: 03-2012
DOI: 10.2216/11-47.1
Algal Parasite Herpodiscus durvillaeae (Phaeophyceae: Sphacelariales) Inferred to have Traversed the Pacific Ocean with its Buoyant Host
Publisher: Wiley
Date: 21-11-2013
DOI: 10.1111/JPY.12017
Abstract: The parasitic phaeophycean endophyte Herpodiscus durvillaeae (Lindauer) G. R. South has previously only been recorded from New Zealand, in association with a single host species, Durvillaea antarctica (Chamisso) Hariot (southern bull-kelp). Here we use DNA sequence data from plastid and nuclear markers (chloroplast rbcL, ribosomal LSU, and a nuclear pseudogene copy of COI) to test for the presence of H. durvillaeae beyond the New Zealand region, and on host species other than D. antarctica. Analyses of s les from the Falkland Islands confirm the first record of H. durvillaeae from the Atlantic Ocean. We report that Falkland Islands H. durvillaeae are genetically indistinguishable from s les of this species from New Zealand's sub-Antarctic C bell Island, suggesting recent dispersal of the parasite across the Pacific Ocean, presumably by rafting with its buoyant macroalgal host. We also here record H. durvillaeae from New Zealand endemics Durvillaea poha Fraser et al. and D. willana Lindauer.
Glacial oceanographic contrasts explain phylogeography of Australian bull kelp
Publisher: Wiley
Date: 05-2009
Reconsidering connectivity in the sub-Antarctic
Publisher: Wiley
Date: 29-03-2017
DOI: 10.1111/BRV.12327
Abstract: Extreme and remote environments provide useful settings to test ideas about the ecological and evolutionary drivers of biological ersity. In the sub-Antarctic, isolation by geographic, geological and glaciological processes has long been thought to underpin patterns in the region's terrestrial and marine ersity. Molecular studies using increasingly high-resolution data are, however, challenging this perspective, demonstrating that many taxa disperse among distant sub-Antarctic landmasses. Here, we reconsider connectivity in the sub-Antarctic region, identifying which taxa are relatively isolated, which are well connected, and the scales across which this connectivity occurs in both terrestrial and marine systems. Although many organisms show evidence of occasional long-distance, trans-oceanic dispersal, these events are often insufficient to maintain gene flow across the region. Species that do show evidence of connectivity across large distances include both active dispersers and more sedentary species. Overall, connectivity patterns in the sub-Antarctic at intra- and inter-island scales are highly complex, influenced by life-history traits and local dynamics such as relative dispersal capacity and propagule pressure, natal philopatry, feeding associations, the extent of human exploitation, past climate cycles, contemporary climate, and physical barriers to movement. An increasing use of molecular data - particularly genomic data sets that can reveal fine-scale patterns - and more effective international collaboration and communication that facilitates integration of data from across the sub-Antarctic, are providing fresh insights into the processes driving patterns of ersity in the region. These insights offer a platform for assessing the ways in which changing dispersal mechanisms, such as through increasing human activity and changes to wind and ocean circulation, may alter sub-Antarctic bio ersity patterns in the future.
Geothermal activity helps life survive glacial cycles
Publisher: Proceedings of the National Academy of Sciences
Date: 10-03-2014
Abstract: The evolution and maintenance of ersity through cycles of past climate change have hinged largely on the availability of refugia. Geothermal refugia may have been particularly important for survival through past glaciations. Our spatial modeling of Antarctic bio ersity indicates that some terrestrial groups likely survived throughout intense glacial cycles on ice-free land or in sub-ice caves associated with areas of geothermal activity, from which recolonization of the rest of the continent took place. These results provide unexpected insights into the responses of various species to past climate change and the importance of geothermal regions in promoting bio ersity. Furthermore, they indicate the likely locations of bio ersity “hotspots” in Antarctica, suggesting a critical focus for future conservation efforts.
Human impacts in an urban port: The carbonate budget, Otago Harbour, New Zealand
Publisher: Elsevier BV
Date: 12-2010
The importance of replicating genomic analyses to verify phylogenetic signal for recently evolved lineages
Publisher: Wiley
Date: 04-07-2016
DOI: 10.1111/MEC.13708
Abstract: Genomewide SNP data generated by nontargeted methods such as RAD and GBS are increasingly being used in phylogenetic and phylogeographic analyses. When these methods are used in the absence of a reference genome, however, little is known about the locations and evolution of the SNPs. In using such data to address phylogenetic questions, researchers risk drawing false conclusions, particularly if a representative number of SNPs is not obtained. Here, we empirically test the robustness of phylogenetic inference based on SNP data for closely related lineages. We conducted a genomewide analysis of 75 712 SNPs, generated via GBS, of southern bull-kelp (Durvillaea). Durvillaea chathamensis co-occurs with D. antarctica on Chatham Island, but the two species have previously been found to be so genetically similar that the status of the former has been questioned. Our results show that D. chathamensis, which differs from D. antarctica ecologically as well as morphologically, is indeed a reproductively isolated species. Furthermore, our replicated analyses show that D. chathamensis cannot be reliably distinguished phylogenetically from closely related D. antarctica using subsets (ranging in size from 400 to 10 000 sites) of the 40 912 parsimony-informative SNPs in our data set and that bootstrap values alone can give misleading impressions of the strength of phylogenetic inferences. These results highlight the importance of independently replicating SNP analyses to verify that phylogenetic inferences based on nontargeted SNP data are robust. Our study also demonstrates that modern genomic approaches can be used to identify cases of recent or incipient speciation that traditional approaches (e.g. Sanger sequencing of a few loci) may be unable to detect or resolve.
The genomic footprint of coastal earthquake uplift
Publisher: The Royal Society
Date: 08-07-2020
Abstract: Theory suggests that catastrophic earth-history events can drive rapid biological evolution, but empirical evidence for such processes is scarce. Destructive geological events such as earthquakes can represent large-scale natural experiments for inferring such evolutionary processes. We capitalized on a major prehistoric (800 yr BP) geological uplift event affecting a southern New Zealand coastline to test for the lasting genomic impacts of disturbance. Genome-wide analyses of three co-distributed keystone kelp taxa revealed that post-earthquake recolonization drove the evolution of novel, large-scale intertidal spatial genetic ‘sectors’ which are tightly linked to geological fault boundaries. Demographic simulations confirmed that, following widespread extirpation, parallel expansions into newly vacant habitats rapidly restructured genome-wide ersity. Interspecific differences in recolonization mode and tempo reflect differing ecological constraints relating to habitat choice and dispersal capacity among taxa. This study highlights the rapid and enduring evolutionary effects of catastrophic ecosystem disturbance and reveals the key role of range expansion in reshaping spatial genetic patterns.
European hydromedusa Eleutheria dichotoma (Cnidaria: Hydrozoa: Anthomedusae) found at high densities in New South Wales, Australia: Distribution, biology and habitat
Publisher: Cambridge University Press (CUP)
Date: 15-06-2006
DOI: 10.1017/S0025315406013592
Abstract: Eleutheria dichotoma , a hydrozoan not previously recorded from the southern hemisphere, was found at high densities at several locations along the coast of New South Wales (NSW), Australia, between August and November 2005. The identity of the species was confirmed by morphological and molecular (16S rDNA) comparisons with European specimens. Local densities, distribution and habitat (algal substrate) were examined. The medusae were found along a 400 km stretch of coastline between Bateau Bay (33°23′S 151°29′E) and Pebbly Beach (35°35′S 150°43′E), primarily on the green alga Ulva , at mean densities of more than 50 in iduals per 10 cm 2 plot. The species is probably a recent introduction to Australia.
Flying the nest: male dispersal and multiple paternity enables extrafamilial matings for the invasive bark beetle Dendroctonus micans
Publisher: Springer Science and Business Media LLC
Date: 16-04-2014
DOI: 10.1038/HDY.2014.34
Oceanic rafting by a coastal community
Publisher: The Royal Society
Date: 15-09-2011
Abstract: Oceanic rafting is thought to play a fundamental role in assembling the biological communities of isolated coastal ecosystems. Direct observations of this key ecological and evolutionary process are, however, critically lacking. The importance of macroalgal rafting as a dispersal mechanism has remained uncertain, largely owing to lack of knowledge about the capacity of fauna to survive long voyages at sea and successfully make landfall and establish. Here, we directly document the rafting of a erse assemblage of intertidal organisms across several hundred kilometres of open ocean, from the subantarctic to mainland New Zealand. Multispecies analyses using phylogeographic and ecological data indicate that 10 epifaunal invertebrate species rafted on six large bull kelp specimens for several weeks from the subantarctic Auckland and/or Snares Islands to the Otago coast of New Zealand, a minimum distance of some 400–600 km. These genetic data are the first to demonstrate that passive rafting can enable simultaneous trans-oceanic transport and landfall of numerous coastal taxa.
Crossing the front: Contrasting stormforced dispersal dynamics revealed by biological, geological and genetic analysis of beach-cast kelp
Publisher: The Royal Society
Date: 03-2018
Abstract: The subtropical front (STF) generally represents a substantial oceanographic barrier to dispersal between cold-sub-Antarctic and warm-temperate water masses. Recent studies have suggested that storm events can drastically influence marine dispersal and patterns. Here we analyse biological and geological dispersal driven by two major, contrasting storm events in southern New Zealand, 2017. We integrate biological and physical data to show that a severe southerly system in July 2017 disrupted this barrier by promoting movement of substantial numbers of southern sub-Antarctic Durvillaea kelp rafts across the STF, to make landfall in mainland NZ. By contrast, a less intense easterly storm (Cyclone Cook, April 2017) resulted in more moderate dispersal distances, with minimal dispersal between the sub-Antarctic and mainland New Zealand. These quantitative analyses of approximately 200 freshly beach-cast kelp specimens indicate that storm intensity and wind direction can strongly influence marine dispersal and landfall outcomes.
Founder takes all: Density-dependent processes structure biodiversity
Publisher: Elsevier BV
Date: 02-2013
DOI: 10.1016/J.TREE.2012.08.024
Abstract: Density-dependent processes play a key role in the spatial structuring of bio ersity. Specifically, interrelated demographic processes, such as gene surfing, high-density blocking, and competitive exclusion, can generate striking geographic contrasts in the distributions of genes and species. Here, we propose that well-studied evolutionary and ecological biogeographic patterns of postglacial recolonization, progressive island colonization, microbial sectoring, and even the 'Out of Africa' pattern of human expansion, are fundamentally similar, underpinned by a 'founder takes all' density-dependent principle. Additionally, we hypothesize that older historic constraints of density-dependent processes are seen today in the dramatic biogeographic shifts that occur in response to human-mediated extinction events, whereby surviving lineages rapidly expand their ranges to replace extinct sister taxa.
Southern Hemisphere coasts are biologically connected by frequent, long-distance rafting events
Publisher: Elsevier BV
Date: 07-2022
DOI: 10.1016/J.CUB.2022.05.035
Abstract: Globally, species distributions are shifting in response to environmental change,
Concordant phylogeographic responses to large‐scale coastal disturbance in intertidal macroalgae and their epibiota
Publisher: Wiley
Date: 05-11-2022
DOI: 10.1111/MEC.16245
Abstract: Major ecological disturbance events can provide opportunities to assess multispecies responses to upheaval. In particular, catastrophic disturbances that regionally extirpate habitat‐forming species can potentially influence the genetic ersity of large numbers of codistributed taxa. However, due to the rarity of such disturbance events over ecological timeframes, the genetic dynamics of multispecies recolonization processes have remained little understood. Here, we use single nucleotide polymorphism (SNP) data from multiple coastal species to track the dynamics of cocolonization events in response to ancient earthquake disturbance in southern New Zealand. Specifically, we use a comparative phylogeographic approach to understand the extent to which epifauna (with varying ecological associations with their macroalgal hosts) share comparable spatial and temporal recolonization patterns. Our study reveals concordant disturbance‐related phylogeographic breaks in two intertidal macroalgal species along with two associated epibiotic species (a chiton and an isopod). By contrast, two codistributed species, one of which is an epibiotic hipod and the other a subtidal macroalga, show few, if any, genetic effects of palaeoseismic coastal uplift. Phylogeographic model selection reveals similar post‐uplift recolonization routes for the epibiotic chiton and isopod and their macroalgal hosts. Additionally, codemographic analyses support synchronous population expansions of these four phylogeographically similar taxa. Our findings indicate that coastal paleoseismic activity has driven concordant impacts on multiple codistributed species, with concerted recolonization events probably facilitated by macroalgal rafting. These results highlight that high‐resolution comparative genomic data can help reconstruct concerted multispecies responses to recent ecological disturbance.
An integrated ecological, genetic and geological assessment of long-distance dispersal by invertebrates on kelp rafts
Publisher: California Digital Library (CDL)
Date: 31-12-2018
DOI: 10.21425/F5FBG40888
The Biogeographic Importance of Buoyancy in Macroalgae: A Case Study of the Southern Bull‐Kelp Genus Durvillaea (Phaeophyceae), Including Descriptions of Two New Species1
Publisher: Wiley
Date: 21-11-2019
DOI: 10.1111/JPY.12939
Abstract: Long-distance dispersal plays a key role in evolution, facilitating allopatric ergence, range expansions, and species movement in response to environmental change. Even species that seem poorly suited to dispersal can sometimes travel long distances, for ex le via hitchhiking with other, more intrinsically dispersive species. In marine macroalgae, buoyancy can enable adults-and erse hitchhikers-to drift long distances, but the evolution and role of this trait are poorly understood. The southern bull-kelp genus Durvillaea includes several non-buoyant and buoyant species, including some that have only recently been recognized. In revising the genus, we not only provide updated identification tools and describe two new species (D. incurvata comb. nov. from Chile and D. fenestrata sp. nov. from the Antipodes Islands), but also carry out biogeographic analyses to determine the evolutionary history of buoyancy in the genus. Although the ancestral state was resolved as non-buoyant, the distribution of species suggests that this trait has been both gained and lost, possibly more than once. We conclude that although buoyancy is a trait that can be useful for dispersal (creating evolutionary pressure for its gain), there is also evolutionary pressure for its loss as it restricts species to narrow environmental ranges (i.e., shallow depths).
Contrasting patterns of population structure and demographic history in cryptic species of Bostrychia intricata (Rhodomelaceae, Rhodophyta) from New Zealand
Publisher: Wiley
Date: 14-05-2015
DOI: 10.1111/JPY.12305
Abstract: Spatial patterns of genetic ersity provide insight into the demography and history of species. Morphologically similar but genetically distinct "cryptic" species are increasingly being recognized in marine organisms through molecular analyses. Such species are, on closer inspection, often discovered to display contrasting life histories or occasionally minor morphological differences molecular tools can thus be useful indicators of ersity. Bostrychia intricata, a marine red alga, is widely distributed throughout the Southern Hemisphere and comprises many cryptic species. We used mitochondrial cytochrome c oxidase I gene sequences to assess the genetic variation, population genetic structure, and demographic history of B. intricata in New Zealand. Our results supported the existence of three cryptic species of B. intricata (N2, N4, and N5) in New Zealand. Cryptic species N4, which was found throughout New Zealand, showed a higher genetic ersity and wider distribution than the other two species, which were only found in the North Island and northern South Island. Our analyses showed low to moderate genetic differentiation among eastern North Island populations for cryptic species N2, but high differentiation among North and South Island populations for N4, suggesting different population structure between these cryptic species. Data also indicated that N2 has recently undergone population expansion, probably since the Last Glacial Maximum (LGM), while the higher genetic ersity in N4 populations suggests persistence in situ through the LGM. The contrasting population structures and inferred demographic histories of these species highlight that life history can vary greatly even among morphologically indistinguishable taxa.
Circumpolar dispersal by rafting in two subantarctic kelp-dwelling crustaceans
Publisher: Inter-Research Science Center
Date: 29-04-2010
DOI: 10.3354/MEPS08523
A morphological and phylogenetic investigation into divergence among sympatric Australian southern bull kelps ( Durvillaea potatorum and D. amatheiae sp. nov.)
Publisher: Elsevier BV
Date: 02-2017
DOI: 10.1016/J.YMPEV.2016.12.027
Abstract: Genetic analyses can reveal a wealth of hitherto undiscovered cryptic bio ersity. For co-occurring and morphologically similar species, the combination of molecular, ecological and morphological analyses provides an excellent opportunity for understanding some of the processes that can lead to ergence and speciation. The Australian endemic brown macroalga Durvillaea potatorum (Phaeophyceae) was examined with a combination of genetic and morphological approaches to confirm the presence of two separate species and to infer the processes that led to their ergence. A total of 331 in iduals from 11 sites around coastal Tasmania were collected and measured in situ for a range of morphological and ecological characteristics. Tissue s les were also collected for each in idual to allow genetic analyses using mitochondrial (COI) and nuclear (28S) markers. Genetic analyses confirmed the presence of two deeply ergent clades. The significant morphological differentiation, despite high levels of intra-lineage variability, further supported their recognition as distinct species. We describe a new species, D. amatheiae sp. nov., which is characterised by a narrower and proportionately shorter stipe, shorter total length, and higher number of stipitate lateral blades and branches than D. potatorum (sensu stricto). The occurrence of both species in sympatry along Tasmania's eastern and western coasts, as well as their contrasting patterns of haplotype ersity, supports a hypothesis of geographical isolation, allopatric speciation and subsequent secondary contact in response to sea level and ocean current change throughout the Pleistocene glaciation cycles. This research contributes to resolving the phylogenetic relationships, taxonomy and evolution of the ecologically keystone kelp genus Durvillaea.
Contemporary habitat discontinuity and historic glacial ice drive genetic divergence in Chilean kelp
Publisher: Springer Science and Business Media LLC
Date: 2010
Meta‐analysis of Antarctic phylogeography reveals strong sampling bias and critical knowledge gaps
Publisher: Wiley
Date: 22-11-2022
DOI: 10.1111/ECOG.06312
Abstract: Much of Antarctica's highly endemic terrestrial bio ersity is found in small ice‐free patches. Substantial genetic differentiation has been detected among populations across spatial scales. S ling is, however, often restricted to commonly‐accessed sites and we therefore lack a comprehensive understanding of broad‐scale biogeographic patterns, which could impede forecasts of the nature and impacts of future change. Here, we present a synthesis of published genetic studies across terrestrial Antarctica and the broader Antarctic region, aiming to identify current biogeographic patterns, environmental drivers of ersity and future research priorities. A database of all published genetic research from terrestrial fauna and flora (excl. microbes) across the Antarctic region was constructed. This database was then filtered to focus on the most well‐represented taxa and markers (mitochondrial COI for fauna, and nuclear ITS for flora). The final dataset comprised 7222 records, spanning 153 studies of 335 different species. There was strong taxonomic bias towards flowering plants (52% of all floral data sets) and springtails (54% of all faunal data sets), and geographic bias towards the Antarctic Peninsula and Victoria Land. Recent connectivity between the Antarctic continent and neighbouring landmasses, such as South America and the Southern Ocean Islands (SOIs), was inferred for some groups, but patterns observed for most taxa were strongly influenced by s ling biases. Above‐ground wind speed and habitat heterogeneity were positively correlated with genetic ersity indices overall though environment was a generally poor predictor of genetic ersity. The low resolution and variable coverage of data may also have reduced the power of our comparative inferences. In the future, higher‐resolution data, such as genomic SNPs and environmental modelling, alongside targeting s ling of remote sites and under s led taxa, will address current knowledge gaps and greatly advance our understanding of evolutionary processes across the Antarctic region.
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