scholarly journals Oceanic rafting by a coastal community

2010 ◽  
Vol 278 (1706) ◽  
pp. 649-655 ◽  
Author(s):  
Ceridwen I. Fraser ◽  
Raisa Nikula ◽  
Jonathan M. Waters

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 diverse 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.

2018 ◽  
Vol 32 (2) ◽  
pp. 253 ◽  
Author(s):  
Jonathan M. Waters ◽  
Tania M. King ◽  
Ceridwen I. Fraser ◽  
Chris Garden

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.


The Condor ◽  
2019 ◽  
Vol 121 (3) ◽  
Author(s):  
Nicolas J Rawlence ◽  
Matt J Rayner ◽  
Tim G Lovegrove ◽  
Debbie Stoddart ◽  
Melanie Vermeulen ◽  
...  

Abstract Genetic data are increasingly being used to prioritize species conservation in a fiscally constrained age of seemingly boundless conservation crises. Such data can also reveal previously cryptic biodiversity requiring further revision of conservation management guidelines. Using a combination of mitochondrial (control region) and nuclear (beta fibrinogen intron 7) DNA, and morphology, we reveal that the endemic New Zealand Spotted Shag (Phalacrocorax punctatus) complex exhibits phylogenetic structure that is decoupled from previously recorded qualitative morphological variation. Crucially, the most genetically distinct populations within P. punctatus are from northern New Zealand; recent surveys show that these populations, which house important genetic diversity within Spotted Shags, are in danger of being extirpated. In contrast, we find the previously phenotypically differentiated nominate (P. punctatus punctatus) and Blue (P. punctatus oliveri) Shag subspecies show no genetic and morphological separation, and are of least conservation concern.


2014 ◽  
Vol 281 (1786) ◽  
pp. 20140097 ◽  
Author(s):  
Catherine J. Collins ◽  
Nicolas J. Rawlence ◽  
Stefan Prost ◽  
Christian N. K. Anderson ◽  
Michael Knapp ◽  
...  

Extinctions can dramatically reshape biological communities. As a case in point, ancient mass extinction events apparently facilitated dramatic new evolutionary radiations of surviving lineages. However, scientists have yet to fully understand the consequences of more recent biological upheaval, such as the megafaunal extinctions that occurred globally over the past 50 kyr. New Zealand was the world's last large landmass to be colonized by humans, and its exceptional archaeological record documents a vast number of vertebrate extinctions in the immediate aftermath of Polynesian arrival approximately AD 1280. This recently colonized archipelago thus presents an outstanding opportunity to test for rapid biological responses to extinction. Here, we use ancient DNA (aDNA) analysis to show that extinction of an endemic sea lion lineage ( Phocarctos spp.) apparently facilitated a subsequent northward range expansion of a previously subantarctic-limited lineage. This finding parallels a similar extinction–replacement event in penguins ( Megadyptes spp.). In both cases, an endemic mainland clade was completely eliminated soon after human arrival, and then replaced by a genetically divergent clade from the remote subantarctic region, all within the space of a few centuries. These data suggest that ecological and demographic processes can play a role in constraining lineage distributions, even for highly dispersive species, and highlight the potential for dynamic biological responses to extinction.


2003 ◽  
Vol 51 (6) ◽  
pp. 673 ◽  
Author(s):  
S. A. Halse ◽  
J. K. Ruprecht ◽  
A. M. Pinder

Saline water was common in south-west Western Australian aquatic systems prior to land-clearing because most streams and wetlands were ephemeral and evapo-concentrated as they dried, and there were high concentrations of stored salt in groundwater and soil profiles. Nevertheless, a 1998 review of salinity trends in rivers of south-west Western Australia showed that 20-fold increases in salinity concentrations had occurred since clearing in the medium-rainfall zone (300–700 mm). More recent data confirm these trends and show that elevated salinities have already caused substantial changes to the biological communities of aquatic ecosystems. Further substantial changes will occur, despite the flora and fauna of the south-west being comparatively well adapted to the presence of salinity in the landscape. Up to one-third of wetland and river invertebrate species, large numbers of plants and a substantial proportion of the waterbird fauna will disappear from the wheatbelt, a region that has high biodiversity value and endemism. Increased salinities are not the only threat associated with salinisation: increased water volumes, longer periods of inundation and more widespread acidity are also likely to be detrimental to the biota.


2018 ◽  
Vol 34 (4) ◽  
pp. 803-810 ◽  
Author(s):  
Mary-Ann Carter ◽  
Louise N Signal ◽  
Richard Edwards ◽  
Janet Hoek

AbstractDespite the global popularity of sport, we know surprisingly little about food in sports settings. This two-phased study analysed the foods available in New Zealand sports settings. Phase one included a systematic literature review and 18 interviews with key informants from national and regional sporting organizations. Phase two involved 37 key informant interviews with stakeholders from two exemplar sports, rugby and netball and direct observations at netball and rugby venues. This study found most foods and beverages at New Zealand sports events were energy-dense and nutrient-poor. Caterers’ control over food provision, socio-cultural attitudes which view unhealthy foods as normal, and a dominant profit motive, appear to be the key factors influencing the food environment in sports settings. Food environments in sport settings provide frequent opportunities to purchase and consume energy-dense, nutrient-poor foods. The research shows we have competing players in the sports context—unhealthy food and healthy physical activity. Achieving sustainable healthy change in sports settings will be challenging when the prevailing attitude normalizes the unhealthy environment. Nutrition policies in sports clubs are urgently needed to increase the availability of healthy food. This requires support from health agencies and leadership from national sports organizations. Given the international nature of the food industry and sport, these findings from New Zealand may assist other countries to better understand the nature of food in sport and adopt appropriate interventions to reduce the obesogenic environment that is sport.


2021 ◽  
Author(s):  
◽  
Phil J. Sirvid

<p>The New Zealand Thomisidae (crab spiders) are represented in New Zealand by two subfamilies (Stephanopinae and Thomisinae) and were used as a model group to test two competing theories on the origins of the New Zealand spider fauna. The New Zealand thomisids are also given their first full taxonomic revision. The two origin models essentially represent species radiations following recent dispersal or ancient vicariance events. Modern distribution data suggested that the stephanopines are poor dispersers and may provide evidence demonstrating a long period of separation from Australia; while in contrast, thomisines are known to be excellent dispersers. Maximum Likelihood and Bayesian analyses of cytochrome c suboxidase subunit I (COI), 28S ribosomal RNA (28S), histone H3 (H3), NADH dehyrogenase 1 (ND1) data and a combined genetic dataset was undertaken. Results indicate New Zealand stephanopines and thomisines form distinct endemic groups separate from sampled Australian species and appear to have separated from them around 5-6 million years ago. Additionally, genetic data from this study showed i) colour variations are not indicative of cryptic species; ii) previously described species are genetically distinct; iii) several suspected new species are also genetically distinct; iv) the relatively recent establishment of two Australian stephanopines and the occurrence of similar COI haplotypes in disjunct locations suggest that the dispersal ability of stephanopines is greater than previously thought and that radiation following colonization from Australia is a plausible explanation for the current diversity of the New Zealand thomisid biota. The taxonomic revision raises the number of described species from eight to eleven based on a combination of morphological and genetic data. In the stephanopines, Bryantymella Gen. nov. is erected to contain the type species Bryantymella angularis (Urquhart, 1885) comb. nov. as well as B. angulata (Urquhart, 1885) comb. nov., B. thorini sp. nov. and B. brevirostris sp. nov. Two Australian species, Sidymella longipes (Koch, 1874) and S. trapezia (Koch, 1874), are also recorded for New Zealand. Sidymella benhami (Hogg, 1910) is considered to be a junior synonym of Bryantymella angulata (Urquhart, 1885). In the thomisines, all species are now included in the previously monotypic genus Cymbachina Bryant, 1933. The genus now encompasses the type species C. albobrunnea (Urquhart, 1893), C. ambara (Urquhart, 1885) comb. nov., C. albolimbata (L. Koch, 1893) comb. nov., C. sphaeroides (Urquhart, 1885) comb. nov. and D. urquharti sp. nov. Synema suteri Dahl, 1907 is regarded as a junior synonym of C. ambara (L. Koch 1893). All previously described species are redescribed to a modern standard and sexes for some species are described for the first time. Three new species are described. Photographs of adults and diagnostic genitalic characters are included, as are diagnostic keys and updated synonymic, geographic and biological information. Overall, this study indicates that New Zealand thomisids appear to have split from their Australian relatives some 5-6 million years ago and taken in concert with the recent establishment of two Australian stephanopine species, it appears that dispersal to New Zealand by Australian colonists and subsequent radiation into endemic New Zealand forms is a plausible explanation for the current state of the fauna. Genetic and morphological data are mutually supporting and in concert have helped inform the first taxonomic revision ever undertaken for this family in New Zealand.</p>


2021 ◽  
Author(s):  
◽  
Shay B. O'Neill

<p>The endemic fauna of the South Island has proven to be an ideal taxonomic group to examine the impact of climatic and geological processes on the evolution of New Zealand's biota since the Pliocene. This thesis examines the phylogeography of McCann's skink (Oligosoma maccanni) in order to provide insight into the relative contribution of Pliocene and Pleistocene processes on patterns of genetic structure in South Island biota. This thesis also investigates the phylogeography of the brown skink (O. zelandicum) to examine whether Cook Strait landbridges facilitated gene flow between the North and South Island in the late-Pleistocene. This thesis also investigates the presence of genealogical concordance across independent loci for the endemic alpine stick insect, Niveaphasma. I obtained mitochondrial DNA (mtDNA) sequence data (ND2 and ND4; 1284 bp) from across the range of both skink species and mtDNA (COI; 762 bp) and nuclear sequence data (EF1 ; 590 bp) from across the range of Niveaphasma. I used DGGE in order to resolve nuclear EF1 alleles and examined phylogeographic patterns in each species using Neighbour-Joining, Maximum Likelihood and Bayesian methods. Substantial phylogeographic structure was found within O. maccanni, with divergences among clades estimated to have occurred during the Pliocene. Populations in the Otago/Southland region formed a well-supported lineage within O. maccanni. A genetic break was evident between populations in east and west Otago, while north-south genetic breaks were evident within the Canterbury region. There was relatively minor phylogeographic structure within O. zelandicum. Our genetic data supports a single colonization of the North Island by O. zelandicum from the South Island, with the estimated timing of this event (0.46 Mya) consistent with the initial formation of Cook Strait. There was substantial genetic structuring identified within Niveaphasma, with a well-supported lineage present in the Otago/Southland region. There was also a genetic break between populations in Canterbury and eastern Otago with those in central Otago and Southland. The genetic data provided strong genealogical concordance between mtDNA haplotypes and nuclear alleles suggesting an accurate depiction of the historical isolation identified between the major clades of Niveaphasma. This finding offers compelling evidence for the use of nuclear gene  phylogeography alongside mtDNA for future evolutionary studies within New Zealand.</p>


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