Patterns of diversity and habitat relationships in terrestrial mollusc communities of the Pukeamaru Ecological District, northeastern New Zealand

Aim The New Zealand terrestrial mollusc fauna is among the most speciose in the world, with often remarkably high richness at lowland forest sites. We sought to elucidate general explanations for patterns of richness in terrestrial mollusc communities by analysis of species coexistence and habitat relationships within a New Zealand district fauna. Location Pukeamaru Ecological District, eastern North Island, New Zealand. Methods We sampled molluscs using qualitative methods at twenty-three sites and quantitatively by frame sampling of scrubland-forest floor litter at sixteen of these sites and analysed patterns of species richness and turnover in relation to regional species pools and local habitat attributes. We then tested for nonrandom assemblage of taxa along diversity and habitat gradients. Results Ninety-four indigenous mollusc species were recorded from a district fauna estimated at 102 indigenous species: only two species were endemic. From the presumptive geological history of the district, the low endemism, and Brooks parsimony and indicator species analyses of faunal relationships, the communities were indicated to have resulted by accumulation of colonists from other New Zealand districts since the Miocene. Richness ranged from two or three indigenous species in dune habitats to fifty-nine species in a floristically rich forest. Beta diversity was high and site occupancy per species was low, indicating communities structured by successive replacement of ecological equivalents. Sites differing in vegetation had characteristic species assemblages, indicating a degree of habitat specialization. Canonical correspondence analysis indicated that canopy tree species, canopy height, floristic diversity, altitude, litter mass, and litter pH were important determinants of species assemblage in scrubland and forest. Richness was strongly associated with site floristic diversity and, for litter-dwelling species, the pH of litter substrate. High richness occurred at those sites supporting molluscs in high abundance. Shell-shape distributions were essentially Cainian unimodal, with communities dominated by snail species with subglobose to discoidal shells. Mean and variance of shell size increased with mollusc species richness and floristic diversity at sites, indicating dominance of communities by small-shelled species at early successional or floristically poor sites, and increased richness resulting from addition of larger snails into vacant niches. Shifts in shell form were associated with sympatry in several congeneric taxa. Main conclusions The underdispersion of shell shape, relative to faunas elsewhere in the world, indicates that community structure in New Zealand land snail faunas has been constrained by limited phylogenetic diversity and/or by convergence upon successful adaptations. The remarkably high richness that characterizes these communities indicates special conditions allow coexistence of numerous species. The relationship between floristic diversity at sites and the richness, diversity, and shell-size distributions of the molluscs suggests assemblages structured around niche partitioning among competing species. While there is an element of congruence between vegetation and mollusc pattern, this study indicates that assembly rules will be defined, and spatial pattern predicted, only through a better understanding of the linkage between regional species pool, organism traits, environment, and local community assemblage.     

Parasitism in species of Bathymodiolus (Bivalvia: Mytilidae) mussels from deep-sea seep and hydrothermal vents

Bivalve species, especially mussels, are biomass dominants in many deep-sea chemosynthetic ecosystems. As in shallow-water environments, parasites are likely to be important factors in the population dynamics of bivalve communities in chemosynthetic ecosystems, but there has been little study of parasitism in deep-sea seep or vent molluscs. In this study, parasite types, diversity, prevalence, infection density and non-infectious indicators of stress or disease as related to host age, reproductive condition, and endosymbiont density were assessed in mussels (Bathymodiolus heckerae) from 2 seep sites and mussels (B. puteoserpentis) from 2 vent sites. We identified 10 microbial or parasitic agents in histological sections. Parasite types included 3 viral-like gut inclusions, 2 rickettsia-like gill inclusions, a rickettsia-like mantle inclusion, a bacterial gill-rosette, a chlamydia-like gut inclusion, gill-dwelling ciliates, and an unidentified inclusion in gut tissues. Parasite species richness was greater in seep mussels than in vent mussels, with the seep mussels possessing 9 types of parasites compared to 2 in the vent mussels. One of the viral-like inclusions infecting the seep mussel B. heckerae was pathogenic, causing lysis of the digestive tubules. The prevalence and intensity of infection by this pathogen were greater in hosts with shell lengths less than 100 mm. Mussels from all 4 sites also exhibited intense infiltration of tissues and blood spaces by enlarged hemocytes. Hemocytic infiltration (hemocytosis) showed variable degrees of severity that were not associated with other host factors examined.     

Invasive blue mussels threaten regional scale genetic diversity in mainland and remote offshore locations: the need for baseline data and enhanced protection in the Southern Ocean

Human‐mediated biological transfers of species have substantially modified many ecosystems with profound environmental and economic consequences. However, in many cases, invasion events are very hard to identify because of the absence of an appropriate baseline of information for receiving sites/regions. In this study, use of high‐resolution genetic markers (single nucleotide polymorphisms – SNPs) highlights the threat of introduced Northern Hemisphere blue mussels (Mytilus galloprovincialis) at a regional scale to Southern Hemisphere lineages of blue mussels via hybridization and introgression. Analysis of a multispecies SNP dataset reveals hotspots of invasive Northern Hemisphere blue mussels in some mainland New Zealand locations, as well as the existence of unique native lineages of blue mussels on remote oceanic islands in the Southern Ocean that are now threatened by invasive mussels. Samples collected from an oil rig that has moved between South Africa, Australia, and New Zealand were identified as invasive Northern Hemisphere mussels, revealing the relative ease with which such non‐native species may be moved from region to region. In combination, our results highlight the existence of unique lineages of mussels (and by extension, presumably of other taxa) on remote offshore islands in the Southern Ocean, the need for more baseline data to help identify bioinvasion events, the ongoing threat of hybridization and introgression posed by invasive species, and the need for greater protection of some of the world's last great remote areas.     

Interlineage Mytilus galloprovincialis Lmk. 1819 hybridization yields inconsistent genetic outcomes in the Southern hemisphere

A Southern hemisphere lineage of the blue mussel Mytilus galloprovincialis has been diverging in allopatry from Northern hemisphere conspecifics for 0.84–1.2 million years. Secondary contact between Southern and Northern hemisphere mussels in Chile, New Zealand and Australia provides an opportunity to better understand the extent and consequences of extensive range expansion. Non-native M. galloprovincialis and hybrids, as detected from RFLP assays of nuclear and mitochondrial DNA, are present in all three countries and significant cytonuclear disequilibria exist for native homozygotes in Chile and New Zealand, non-native homozygotes in Chile and non-native heterozygotes in New Zealand. Introductions into Australia are rare events given that no pure non-native mussels were detected. Immigration from one or both taxa into the hybrid zone may underlie disequilibria in New Zealand, whilst gender-directional crossing with limited ongoing hybridization contributes to disequilibria in Chile. Hybridization dynamics do not pose a threat to the Southern lineage in Chile and Australia, but in New Zealand, introgression, continued immigration and slight hybridization gender bias towards non-native maternal parents could lead to the regional extirpation of the native lineage.     

Exploration of the Canyon-Incised Continental Margin of the Northeastern United States Reveals Dynamic Habitats and Diverse Communities

The continental margin off the northeastern United States (NEUS) contains numerous, topographically complex features that increase habitat heterogeneity across the region. However, the majority of these rugged features have never been surveyed, particularly using direct observations. During summer 2013, 31 Remotely-Operated Vehicle (ROV) dives were conducted from 494 to 3271 m depth across a variety of seafloor features to document communities and to infer geological processes that produced such features. The ROV surveyed six broad-scale habitat features, consisting of shelf-breaching canyons, slope-sourced canyons, inter-canyon areas, open-slope/landslide-scar areas, hydrocarbon seeps, and Mytilus Seamount. Four previously unknown chemosynthetic communities dominated by Bathymodiolus mussels were documented. Seafloor methane hydrate was observed at two seep sites. Multivariate analyses indicated that depth and broad-scale habitat significantly influenced megafaunal coral (58 taxa), demersal fish (69 taxa), and decapod crustacean (34 taxa) assemblages. Species richness of fishes and crustaceans significantly declined with depth, while there was no relationship between coral richness and depth. Turnover in assemblage structure occurred on the middle to lower slope at the approximate boundaries of water masses found previously in the region. Coral species richness was also an important variable explaining variation in fish and crustacean assemblages. Coral diversity may serve as an indicator of habitat suitability and variation in available niche diversity for these taxonomic groups. Our surveys added 24 putative coral species and three fishes to the known regional fauna, including the black coral Telopathes magna, the octocoral Metallogorgia melanotrichos and the fishes Gaidropsarus argentatus, Guttigadus latifrons, and Lepidion guentheri. Marine litter was observed on 81% of the dives, with at least 12 coral colonies entangled in debris. While initial exploration revealed the NEUS region to be both geologically dynamic and biologically diverse, further research into the abiotic conditions and the biotic interactions that influence species abundance and distribution is needed.     

A review of the freshwater ostracods of New Zealand

Summary The freshwater ostracod fauna of New Zealand is reviewed, and a key is given to the 28 known living species, belonging to 18 genera. 10 new species are described, and 8 genera are recorded for the first time from New Zealand. Brief notes on the habitat and life-history of some of the species are given.Present address: Dept. of Zoology, The University, Glasgow     

Bivalves in a bottleneck: taxonomy,phylogeography and conservation of freshwater mussels (Bivalvia: Unionoida) in Australasia

The conservation biology of Australasian freshwater mussels is hindered by lack of a taxonomic framework that employs molecular data as a complement to shell characters, larval forms and internal anatomy. The fauna includes more than 32 known species (30+ Hyriidae, 2 Unionidae), but has not been revised for 55 years, despite minor amendments. The hyriids are relics of Gondwana, represented in Australia and New Guinea by the ancestral Velesunioninae and in Australia and New Zealand by the Hyriinae (Tribe Hyridellini). Many taxonomic and phylogeographic issues await resolution, including the relationships between Australasian and South American species, and between Australian and New Zealand species, and the status of species in New Guinea (including uncertain reports of Unionidae) and the Solomon Islands. Once these are clarified, it will be easier to identify threatened species and evaluate the conservation status of the fauna. At present, only seven taxa are named in the IUCN Red List or under national/state legislation, and these are not representative. Threatening processes include altered flow regimes, catchment disturbances, salinisation, pollution and invasive species. While the need for a taxonomic revision is paramount, progress in conservation may depend also upon involving the wider community.     

Biogeography and Potential Exchanges Among the Atlantic Equatorial Belt Cold-Seep Faunas

Like hydrothermal vents along oceanic ridges, cold seeps are patchy and isolated ecosystems along continental margins, extending from bathyal to abyssal depths. The Atlantic Equatorial Belt (AEB), from the Gulf of Mexico to the Gulf of Guinea, was one focus of the Census of Marine Life ChEss (Chemosynthetic Ecosystems) program to study biogeography of seep and vent fauna. We present a review and analysis of collections from five seep regions along the AEB: the Gulf of Mexico where extensive faunal sampling has been conducted from 400 to 3300m, the Barbados accretionary prism, the Blake ridge diapir, and in the Eastern Atlantic from the Congo and Gabon margins and the recently explored Nigeria margin. Of the 72 taxa identified at the species level, a total of 9 species or species complexes are identified as amphi-Atlantic. Similarity analyses based on both Bray Curtis and Hellinger distances among 9 faunal collections, and principal component analysis based on presence/absence of megafauna species at these sites, suggest that within the AEB seep megafauna community structure is influenced primarily by depth rather than by geographic distance. Depth segregation is observed between 1000 and 2000m, with the middle slope sites either grouped with those deeper than 2000m or with the shallower sites. The highest level of community similarity was found between the seeps of the Florida escarpment and Congo margin. In the western Atlantic, the highest degree of similarity is observed between the shallowest sites of the Barbados prism and of the Louisiana slope. The high number of amphi-atlantic cold-seep species that do not cluster according to biogeographic regions, and the importance of depth in structuring AEB cold-seep communities are the major conclusions of this study. The hydrothermal vent sites along the Mid Atlantic Ridge (MAR) did not appear as “stepping stones” for dispersal of the AEB seep fauna, however, the south MAR and off axis regions should be further explored to more fully test this hypothesis.     

Zoogeography and relationships of Australasian skates (Chondrichthyes: Rajidae)

Aim To investigate distributional patterns and derivation of skates in the Australasian realm. Location Australasia. Methods Genus‐group skate taxa were defined for this region for the first time and new systematic information, as well as bathymetric and geographical data, used to identify distribution patterns. Results The extant skate fauna of Australasia (Australia, New Zealand, New Caledonia and adjacent subAntarctic dependencies) is highly diverse and endemic with sixty‐two species from twelve currently recognized, nominal genus‐group taxa. These include the hardnose skate (rajin) groups Anacanthobatis, Amblyraja, Dipturus, Okamejei, Rajella and Leucoraja, and softnose skate (arhynchobatin) genera Arhynchobatis, Bathyraja, Insentiraja, Irolita, Pavoraja and Notoraja. Additional new and currently unrecognized nominal taxa of both specific and supraspecific ranks also occur in the region. The subfamily Arhynchobatinae is particularly speciose in Australasia, and the New Zealand/New Caledonian fauna is dominated by undescribed supraspecific taxa and species. The Australian fauna, although well represented by arhynchobatins, is dominated by Dipturus‐like skates and shows little overlap in species composition with the fauna of New Zealand and New Caledonia. Similarly, these faunas exhibit no overlap with the polar faunas of the Australian subAntarctic dependencies (Heard and Macdonald Islands) to the south. Skates appear to be absent from the Macquarie Ridge at the southern margin of the New Zealand Plateau. Their absence off New Guinea probably reflects inadequate sampling and the subsequent poor knowledge of that region's deepwater fish fauna. Main conclusions Skates appear to have existed in the eastern, Australasian sector of Gondwana before fragmentation in the late Cretaceous. The extant fauna appears to be derived from elements of Gondwanan origin, dispersal from the eastern and western Tethys Sea, and intraregional vicariance speciation.     

Comparative composition, diversity and trophic ecology of sediment macrofauna at vents, seeps and organic falls

Sediments associated with hydrothermal venting, methane seepage and large organic falls such as whale, wood and plant detritus create deep-sea networks of soft-sediment habitats fueled, at least in part, by the oxidation of reduced chemicals. Biological studies at deep-sea vents, seeps and organic falls have looked at macrofaunal taxa, but there has yet to be a systematic comparison of the community-level attributes of sediment macrobenthos in various reducing ecosystems. Here we review key similarities and differences in the sediment-dwelling assemblages of each system with the goals of (1) generating a predictive framework for the exploration and study of newly identified reducing habitats, and (2) identifying taxa and communities that overlap across ecosystems. We show that deep-sea seep, vent and organic-fall sediments are highly heterogeneous. They sustain different geochemical and microbial processes that are reflected in a complex mosaic of habitats inhabited by a mixture of specialist (heterotrophic and symbiont-associated) and background fauna. Community-level comparisons reveal that vent, seep and organic-fall macrofauna are very distinct in terms of composition at the family level, although they share many dominant taxa among these highly sulphidic habitats. Stress gradients are good predictors of macrofaunal diversity at some sites, but habitat heterogeneity and facilitation often modify community structure. The biogeochemical differences across ecosystems and within habitats result in wide differences in organic utilization (i.e., food sources) and in the prevalence of chemosynthesis-derived nutrition. In the Pacific, vents, seeps and organic-falls exhibit distinct macrofaunal assemblages at broad-scales contributing to ß diversity. This has important implications for the conservation of reducing ecosystems, which face growing threats from human activities.     

Process and pattern in the biogeography of New Zealand – a global microcosm?

Aim  To describe New Zealand's historical terrestrial biogeography and place this history in a wider Southern Hemisphere context.
Location  New Zealand.
Methods  The analysis is based primarily on literature on the distributions and relationships of New Zealand's terrestrial flora and fauna.
Results  New Zealand is shown to have a biota that has broad relationships, primarily around the cool Southern Hemisphere, as well as with New Caledonia to the north. There are hints of ancient Gondwanan taxa, although the long-argued predominance of taxa derived by vicariant processes, driven by plate tectonics and the fragmentation of Gondwana, is no longer accepted as a principal explanation of the biota's origins and relationships.
Main conclusions  Most of the terrestrial New Zealand flora and fauna has clearly arrived in New Zealand much more recently than the postulated separation of New Zealand from Gondwana, dated at c. 80 Ma. There is a view that New Zealand may have disappeared completely beneath the sea in the early Cenozoic, and acceptance of this would mean derivation of the entire biota by transoceanic dispersal. However, there are elements in the biota that seem to have broad distributions that date back to Gondwanan times, and also some that are thought unlikely to have been able to disperse to New Zealand across ocean gaps, especially freshwater organisms. Very strong connections to the biota of Australia, rather than to South America, are inconsistent with the timing of New Zealand's ancient and early separation from Gondwana and seem likely to have resulted from dispersal.     

Global diversity of oligochaetous clitellates (“Oligochaeta”; Clitellata) in freshwater

One of the predicted consequences of climate change is an increase in the occurrence of extreme rainfall and a subsequent increase in frequency of high flow events in rivers. High flow events have the potential to impact estuarine communities like mussel assemblages due to decreased salinity and/or the transport of sediments, organic matter and nutrients from the terrestrial environment to the estuary. The impact of two high flow events was investigated using mussels located within the Conwy estuary, North Wales, using the ‘Beyond BACI’ approach. Three study sites were chosen, the potentially impacted site (Conwy) and two control sites located outside the estuary. Sampling took place over 18 months with samples being collected before and after each event. On each sampling occasion, the following data were collected: the total haemocyte count (THC) and condition index (CI) of the mussels and the diversity (Hlog_e) of their associated macrofauna. A significant effect of the first event (22nd October 2004) was found on the CI of the Conwy mussels, whereas a significant effect of the second event (10th October 2005) was found on mussel THC. No effect of either event was found on the diversity of the associated fauna. The results of this study suggest that any increase in the number or intensity of heavy precipitation or high flow events have potential implications for the health and resilience of estuarine mussel populations. Guest editors: J. Davenport, G. Burnell, T. Cross, M. Emmerson, R. McAllen, R. Ramsay & E. Rogan Challenges to Marine Ecosystems     

Rules for macroorganisms applied to microorganisms: patterns of endemism in benthic freshwater diatoms

Ecological theory based on the dynamic equilibrium model (DEM) suggests that maintenance of endemic taxa is most likely in stable, unproductive environments. We tested whether this hypothesis, which was developed mainly using terrestrial plant examples, held when applied to distributions of benthic freshwater diatoms in New Zealand. Given current arguments for the ubiquity of microbial organisms, with distributions determined mainly by environmental tolerances, demonstration that distinctive taxa with evidently restricted distributions conform to theory applicable to larger organisms would lend support to the opposite point of view, that barriers to dispersal do exist. We examined diatom communities from over 320 sites representing the entire spectrum of freshwater habitats in New Zealand and assessed relative abundances of the main taxa present. Each taxon distinguished was assigned to one of five distribution categories ranging from cosmopolitan to endemic. We derived indices of disturbance and productivity for each site using the River Environment Classification (REC), a GIS-based classification system developed for New Zealand rivers. Diatom taxa assigned to endemic or distinctive potential endemic categories were significantly more abundant in low disturbance sites but occurred across a range of productivities. However, bogs and tarns, both of which fell mainly into low disturbance and productivity classes, were distinctive in supporting relatively high proportions of endemic and potential endemic diatoms. Thus our findings in general conformed to the patterns predicted by the DEM, thereby supporting the role of dispersal limitation in diatoms. At the same time, conformity with the DEM helps to explain the continued coexistence in New Zealand freshwaters of many common and apparently cosmopolitan taxa with endemic diatoms, since the DEM explanation for maintenance of endemism does not rely on geographic isolation of species.     

Vicars,tramps and assembly of the New Zealand avifauna: a review of molecular phylogenetic evidence

The avifauna of New Zealand is taxonomically and ecologically distinctive, as is typical of island biotas. However, the potential for an old geological age of New Zealand has encouraged a popular notion of a ‘Moa’s ark’ based on the idea that much of the fauna was isolated when Zealandia broke from Gondwana c. 83 million years ago. Molecular phylogenetics has proved useful for exploring the relative importance of different biogeographical processes, revealing for example that ‘tramp’ species (widely dispersing taxa) have arrived in New Zealand even in the last few hundred years, and that some avian taxa have close phylogenetic relatives overseas (predominantly Australian), indicating their recent ancestors were tramps, too. Distinctive taxa with deep phylogenetic ancestry might be ‘vicars’ that owe their presence to vicariance, but lack of close morphological, taxonomic and phylogenetic affinity provides only tenuous evidence for this. Disproving the alternative possibility that apparent vicars are descended from tramps that dispersed in earlier times remains challenging, but molecular analyses have yielded startling insights. Among New Zealand’s iconic taxa, the world’s largest eagle shared a Pleistocene ancestor with a small Australian eagle, and giant, flightless moa are phylogenetic sisters of the much smaller, flying tinamous of South America. The New Zealand avifauna is neither isolated nor stable, but demonstrative of prolonged and ongoing colonization, speciation and extinction.     

Can natural enemies of current insect pests provide biotic resistance to future pests?

1. Economic pests jeopardize agricultural production worldwide. Classical biological control, comprising the import of exotic natural enemies to control target pest populations, has a successful history in many countries. However, little is known about how these natural enemies contribute to the suppression of pests that are yet to arrive. Biotic resistance theory, though, posits that communities resist species invasions as a result of natural enemies.
2. We assessed the potential of the resident exotic parasitoid wasp fauna in New Zealand (intentionally‐introduced biological control agents and unintentionally‐introduced species) to provide biotic resistance against possible future pests. A dataset was generated containing resident exotic parasitoid species (Ichneumonoidea: Braconidae; Ichneumonidae) in New Zealand, as well as their known global host ranges and the pest status of host species, to infer the potential for biotic resistance.
3. The known exotic ichneumonoid fauna in New Zealand comprises 65 species. These species associate with 107 host species in New Zealand, of which 54 species are pests. However, the current exotic species could potentially suppress 442 pest species not yet occurring in New Zealand.
4. This approach could be used to inform pest management programmes worldwide. Future research should consider how biotic resistance from the established parasitoid fauna can be used to inform specific decisions with respect to classical biological control.

     

Patterns of Deep-Sea Genetic Connectivity in the New Zealand Region: Implications for Management of Benthic Ecosystems

Patterns of genetic connectivity are increasingly considered in the design of marine protected areas (MPAs) in both shallow and deep water. In the New Zealand Exclusive Economic Zone (EEZ), deep-sea communities at upper bathyal depths (<2000 m) are vulnerable to anthropogenic disturbance from fishing and potential mining operations. Currently, patterns of genetic connectivity among deep-sea populations throughout New Zealand’s EEZ are not well understood. Using the mitochondrial Cytochrome Oxidase I and 16S rRNA genes as genetic markers, this study aimed to elucidate patterns of genetic connectivity among populations of two common benthic invertebrates with contrasting life history strategies. Populations of the squat lobster Munida gracilis and the polychaete Hyalinoecia longibranchiata were sampled from continental slope, seamount, and offshore rise habitats on the Chatham Rise, Hikurangi Margin, and Challenger Plateau. For the polychaete, significant population structure was detected among distinct populations on the Chatham Rise, the Hikurangi Margin, and the Challenger Plateau. Significant genetic differences existed between slope and seamount populations on the Hikurangi Margin, as did evidence of population differentiation between the northeast and southwest parts of the Chatham Rise. In contrast, no significant population structure was detected across the study area for the squat lobster. Patterns of genetic connectivity in Hyalinoecia longibranchiata are likely influenced by a number of factors including current regimes that operate on varying spatial and temporal scales to produce potential barriers to dispersal. The striking difference in population structure between species can be attributed to differences in life history strategies. The results of this study are discussed in the context of existing conservation areas that are intended to manage anthropogenic threats to deep-sea benthic communities in the New Zealand region.     

The palaeoecology of the latest Jurassic–earliest Cretaceous hydrocarbon seep carbonates from Spitsbergen,Svalbard

Latest Jurassic–earliest Cretaceous hydrocarbon seeps from Spitsbergen, Svalbard, are known to contain unusual fauna, lacking most of the species characteristic for roughly coeval seep deposits. This study summarizes and analyses the fauna from 16 seep carbonate bodies from Spitsbergen to explain its composition. The seeps formed in a shallow epicontinental sea with widespread deposition of fine‐grained, organic‐rich sediments. They are spread over a relatively large area and are positioned roughly in the same interval, indicating seepage over extensive areas of the palaeo‐Barents Sea. The seep fauna is very species rich and with low dominance, comprising 54 species, with a composition similar to that of Jurassic–Cretaceous normal‐marine environments of other Boreal seas. Seep‐restricted fauna is not abundant and is represented by four species only. Hokkaidoconchids and possible siboglinid worm tubes characteristic for high sulphide fluxes are rare. Apart from seep‐restricted sulphide‐mining lucinid and thyasirid bivalves, chemosymbiosis was also a source of nourishment for background solemyid and nucinellid bivalves, all of which take sulphide from infaunal sources. This all suggests a relatively weak sulphide flux. The high diversity and low dominance of the fauna and significant richness and abundance of background species is typical for shallow water seeps.     

History, current status and future of marine macroalgal research in New Zealand: Taxonomy, ecology, physiology and human uses

New Zealand has a rich and diverse macroalgal flora that has been studied since James Cook's first voyage to New Zealand in 1769. The New Zealand region ranges from cool temperate seas at southerly latitudes to subtropical waters in the north. Here we review the history of phycological research in New Zealand since 1900, and the current status of research in taxonomy, ecology, physiology and seaweed uses including aqua‐culture and seaweed extracts. Some 770 species of seaweed are known to New Zealand, of which 22 are alien. Few taxa have received monographic treatment and many remain to be described. Polysaccharides have been identified from over 80 New Zealand seaweeds and many of these compounds have commercial potential. In addition to urgent taxonomic work, future research should include a national program of long‐term (> 5 years) monitoring of macroalgal communities, rates of growth and primary production, and the contribution of seaweed‐based production to coastal food webs.     

Orthoglymma wangapeka gen.n., sp.n. (Coleoptera: Carabidae: Broscini): a newly discovered relict from the Buller Terrane,north‐western South Island,New Zealand,corroborates a general pattern of Gondwanan endemism

Orthoglymma Liebherr, Marris, Emberson, Syrett & Roig‐Juñent gen.n. (Coleoptera: Carabidae: Broscini) is described to accommodate the single type species Orthoglymma wangapeka Liebherr, Marris, Emberson, Syrett & Roig‐Juñent sp.n., known from the Wangapeka Track, Kahurangi National Park, north‐western South Island, New Zealand. Orthoglymma wangapeka sp.n. is analysed cladistically along with a comprehensive array of 42 other broscine generic terminals and four out‐group taxa, using information obtained from 73 morphological characters, and placed as adelphotaxon to the remainder of subtribe Nothobroscina, a clade distributed in New Zealand, southern South America and Australia. Based on fossil evidence for Carabidae, the occurrence of Orthoglymma wangapeka sp.n. on the Buller Terrane, a geological feature once situated on the eastern margin of Gondwana, and early cladistic divergence of Orthoglymma from the remaining Nothobroscina, Orthoglymma wangapeka sp.n. is interpreted as a Gondwanan relict. The New Zealand arthropod fauna is reviewed to identify other taxa in existence at the time of Cretaceous vicariance of New Zealand and Australia. These candidate Gondwanan taxa, all of which are specified using fossil data or molecular divergence‐based estimates, are analysed biogeographically. Where phylogenetic hypotheses are available, primordial distributions are optimized using event‐based, dispersal‐vicariance (DIVA) analysis. The hypothesized Gondwanan‐aged taxa demonstrate inordinate fidelity to the Gondwanan‐aged geological terranes that constitute the western portions of New Zealand, especially in the South Island. Persistence of these relicts through a hypothesized ‘Oligocene drowning’ event is the most parsimonious explanation for the concentration of Gondwanan relicts in the Nelson, Buller and Fiordland districts of the South Island. Geographic patterns of Gondwanan‐aged taxa are compared with distributions of taxa hypothesized to have colonized New Zealand across the Tasman Sea from Australia and New Caledonia, subsequent to Cretaceous vicariance. These post‐Gondwanan taxa exhibit very different patterns of distribution and diversification in New Zealand, including: (i) abundant endemism in Northland, and the islands and peninsulas of the North Island; (ii) species geographically restricted to areas underlain by the youngest Rakaia and Pahau geological terranes; and (iii) species exhibiting exceedingly widespread geographic distributions spanning geological terranes of disparate ages.

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Composition and zonation of benthic invertebrate communities in a New Zealand kauri forest stream

SUMMARY. The macro-invertebrate fauna of Waitakere River and its tributaries, a northern New Zealand kauri forest stream, was surveyed in January 1974 and January and June 1975, as part of a study on stream community dynamics. This survey and regular samples in the study area provided 144 taxa, almost three times the maximum number previously recorded from a New Zealand stream. Many species were restricted in distribution to a high gradient tributary, or the low gradient mainstream. These did not follow the division into rhithron and potamon families suggested for New Zealand.