Publications by Stephen R Pohe
New Zealand Journal of Ecology, 2022
Te Paki Ecological District (TPED) in Northland, New Zealand, is well known as an ecologically si... more Te Paki Ecological District (TPED) in Northland, New Zealand, is well known as an ecologically significant centre of endemism. However, due to extensive anthropogenic habitat degradation, native forest has been reduced to small, isolated remnants & many of its endemic species are threatened with extinction. Epigeal spider communities (species living on or near the ground) were surveyed within TPED by pitfall trapping at seven native forest remnants differing in plant composition and apparent seral stage to investigate how spider communities varied within them. Surveys were conducted four times over a 12-month period coinciding with winter, spring, summer and autumn. Changes in spider communities were related to differences in plant composition, which were in turn associated with differences in apparent seral stage of the vegetation. Spider communities in forests at later seral stages were dominated by species such as Rinawa, Porrhothele & Uliodon, whereas Euryopis, Cambridgea, Stanwellia & Hypodrassodes were most prevalent in remnants at earlier seral stages. These species could potentially serve as useful bioindicators of ecological succession or restoration. Apart from soil organic matter content none of the predictor variables tested, including plant species richness, were significantly correlated with spider richness or diversity. Spider richness & diversity are most likely determined by a complex interaction of environmental and temporal factors that operate at different spatial scales. This study has increased our understanding of the ecological associations of spider communities & established that TPED is an important centre of endemism for New Zealand spiders. We have also demonstrated the importance of forest remnants as reservoirs of indigenous spider diversity and helped resolve several historical taxonomic issues. Furthermore, we demonstrate the need for taxonomic research in this region of New Zealand & highlight the value of such biodiversity surveys.
Insects, 2022
The mayfly Acanthophlebia cruentata of Aotearoa, New Zealand, is widespread in Te Ika-aMaui North... more The mayfly Acanthophlebia cruentata of Aotearoa, New Zealand, is widespread in Te Ika-aMaui North Island streams, but has never been collected from South Island despite land connection during the last glacial maximum. Population structure of this mayfly might reflect re-colonisation after volcanic eruptions in North Island c1800 years ago, climate cycling or conceal older, cryptic diversity. We collected population samples from 33 locations to estimate levels of population genetic diversity and to document phenotypic variation. Relatively low intraspecific haplotype divergence was recorded among mitochondrial cytb sequences from 492 individuals, but these resolved three geographic-haplotype regions (north, west, east). We detected a signature of isolation by distance at low latitudes (north) but evidence of recent population growth in the west and east. We did not detect an effect of volcanic eruptions but infer range expansion into higher latitudes from a common ancestor during the last glacial period. As judged from wing length, both sexes of adult mayflies were larger at higher elevation and we found that haplotype region was also a significant predictor of Acanthophlebia cruentata size. This suggests that our mitochondrial marker is concordant with nuclear genetic differences that might be explained by founder effect during range expansion.
New Zealand Journal of Zoology, 2020
The invertebrate fauna of five ephemeral forest streams on Hauturu-o-Toi/Little Barrier Island in... more The invertebrate fauna of five ephemeral forest streams on Hauturu-o-Toi/Little Barrier Island in northern New Zealand was assessed in January 2014. Low summer flows restricted benthic sampling largely to pools that would, during periods of ‘normal’ flow, be main-channel riffle/run habitat. Additionally, adult stages of aquatic insects were sampled by light trapping. Fifty-three aquatic species/morphospecies were recorded during the study, including 25 new records, bringing total island species richness to 65. The fauna was dominated by Ephemeroptera and Trichoptera; species richness of Plecoptera and Diptera was low, and only single species of Mollusca and Crustacea were recorded. Species found were either common with broad New Zealand distributions, or species restricted to the North Island. No species was endemic to the island. Faunal comparisons with adjacent mainland streams indicated the island had similar assemblages of core taxa, but generally lower species richness, likely resulting from physiographic differences found there.
New Zealand Journal of Zoology, 2019
New Zealand Entomologist, 2018
New Zealand Natural Sciences, 2018
The New Zealand mayfly (Ephemeroptera) fauna currently comprises 55 described species belonging t... more The New Zealand mayfly (Ephemeroptera) fauna currently comprises 55 described species belonging to 20 genera in eight families. All species and genera are endemic to New Zealand, as are three families. The purpose of this paper is to draw together the fragmented information of published literature in the form of a checklist of New Zealand Ephemeroptera. The checklist is annotated with species authority and publication details, type specimen information (sex, life stage, type locality, collector, specimen repository), distribution and conservation status data, and previously recognised names, including synonyms. References to all valid species descriptions and previously recognised names are included in the bibliography.
New Zealand Journal of Zoology, 2018
The Weta, 2015
The dragonfly Tramea loewii has recently become established in New Zealand, with a known distribu... more The dragonfly Tramea loewii has recently become established in New Zealand, with a known distribution on the Aupouri Peninsula north of Kaitaia. To determine whether the species has spread further south, the littoral zones of eleven central Northland lakes from Ahipara to Waipu were sampled. Searches for exuviae and adults of T. loewii were also conducted at each lake. Larval T. loewii were only found at the Uretiti sand pit lake near Ruakaka, south of Whangarei. Many exuviae and adults in flight were also observed at the lake, indicating the species is established there. This represents a substantial range expansion and is the southernmost record of T. loewii to date.
New Zealand Journal of Marine and Freshwater Research, 2015
The littoral macroinvertebrate faunas of 17 dune lakes on the Aupouri Peninsula in northern New Z... more The littoral macroinvertebrate faunas of 17 dune lakes on the Aupouri Peninsula in northern New Zealand were examined. Land cover of individual catchments was principally sand dunes and scrub, plantation forest, pasture, or a mixture of plantation forest and pasture. Sampling was concentrated in the sedge beds, submerged macrophytes and surface sediment layers of the littoral zone. Sixty-eight invertebrate taxa were recorded, 11–30 per lake. Relative abundance of major faunal groups differed considerably among lakes but a core group of common species was found in three quarters of them. Neither community composition, nor various measures of species richness were related significantly to catchment land cover classes. A feature of the lake fauna was the occurrence of three introduced species of Gastropoda and eight self-introduced insect species, including five dragonflies. One of the latter, Hemicordulia australiae, was found in all lakes and made up 3% of all invertebrates collected.
New Zealand Entomologist, 2013
Life histories of four dragonfly species were investigated in the littoral zone of Lake Heather, ... more Life histories of four dragonfly species were investigated in the littoral zone of Lake Heather, a shallow sand dune lake near Kaitaia in the far north of New Zealand. All four species are self-introduced to New Zealand. Collections of larvae made in seven months from February 2011 to February 2012 were used to infer larval development. Aeshna brevistyla (Aeshnidae), the most abundant species, was semivoltine, Tramea loewii (Libellulidae) and Hemicordulia australiae (Corduliidae) were univoltine and, although difficult to interpret, our data suggest Diplacodes bipunctata (Libellulidae) was bivoltine with autumn and winter-spring generations. Adults of all four species were seen in December and February, T. loewii was also on the wing in late March, A. brevistyla in October and D. bipunctata in November.
The Weta, Jul 2012
Microporus thoreyi (Signoret, 1882) is a poorly known but visually striking member of the heterop... more Microporus thoreyi (Signoret, 1882) is a poorly known but visually striking member of the heteropteran family Cydnidae (burrower or burrowing bugs). It has a shiny black, broadly oval body, and on first glance is easily mistaken for a dorso- ventrally flattened beetle. It has light, orange-brown legs that have a fossorial appearance and prominent bristles along the margins of the thorax. The front of the head (anteocular margin) bears prominent, short stout pegs interspersed with longer bristles. Body length of the three specimens examined by Lariviere in her description of the species ranged from 4.36 - 4.75 mm. Her account also includes a line drawing of M. thoreyi and sketches of the female first gonocoxae and metathoracic scent gland opening. An excellent photograph of the species is provided by Thorpe.
New Zealand Journal of Zoology, 2011
ABSTRACT The dragonfly Tramea loewii (Odonata: Libellulidae) was first seen in New Zealand in 200... more ABSTRACT The dragonfly Tramea loewii (Odonata: Libellulidae) was first seen in New Zealand in 2005, on the Aupouri Peninsula, Northland, and is likely to be self-introduced from Australia. To determine whether the species had become established on the Peninsula, an aquatic survey of 17 lakes was carried out in November 2008. Larvae were found in eight lakes, including six at the southern end of the Peninsula. Most colonised lakes were surrounded by pasture and had dense marginal beds of sedges and rushes where most larvae were collected. Six of an estimated 14 larval instars were found, the penultimate (F-1) and antepenultimate (F-2) instars being most common. The most abundant prey items in the guts of 17 late-instar larvae were Corixidae, chironomid larvae and damselfly larvae. The potential effect of T. loewii on resident lake faunas is discussed briefly.
Theses by Stephen R Pohe
University of Canterbury PhD thesis, 2019
Research link: http://hdl.handle.net/10092/16946 The aim of this thesis is to extend our knowled... more Research link: http://hdl.handle.net/10092/16946 The aim of this thesis is to extend our knowledge of the New Zealand Ephemeroptera (mayflies) with particular reference to the latitudinal and altitudinal distribution of species and community assemblages. The study was centered on a nationwide survey of 81 streams located in predominantly unmodified landscapes, many of which were native forest. Three sites on each stream were sampled by light trapping of imagos (adults) and subimagos as well as supplementary collecting of nymphal stages. An initial study of four types of fluorescent lights showed that although mayflies were attracted to all four types, blacklight and blacklight-blue light were most effective. Because, blacklight-blue light was also less effective at attracting non-target terrestrial species, it was used in the nationwide survey. A total of 47 described mayfly species were obtained in the survey, 85% of the fauna known to occur in the country. Five probable undescribed species were also collected, and several previously described species were recognised as possible ‘morphospecies’ complexes, that may contain cryptic species. Of the almost 14,000 individuals taken in light traps, 39% were imagos and 61% subimagos; 63% of imagos were female, whereas the sex ratio of subimagos was approximately even (54% male, 46% female). Three gynandromorph adults were also collected. Alpha diversity throughout the country ranged from 3–24 species per stream. Species richness declined from north to south, and with increasing altitude, and the similarity of mayfly assemblages to each other declined with distance. Thirty-eight species are recognised from the North Island (15 North Island endemics), 41 from the South Island (16 South Island endemics) and 23 shared by both islands. Species richness on Stewart Island was 14 (1 possible endemic) but further study of the island’s fauna is required. Effects of latitude and altitude were revealed in the widespread and common species Coloburiscus humeralis, which increased in size (forewing length) from north to south, and with altitude. Investigations focusing on two poorly known species, Siphlaenigma janae and Isothraulus abditus, showed they had restricted and fragmented distributions, and were in need of habitat protection to reduce the likelihood of further decline. Genetic structure of S. janae, assessed using the barcoding fragment of the mitochondrial COI gene, indicated the presence of geographically distinct haplotype networks in the northern and central North Island, and the northwest South Island. Isothraulus abditus, which was found only in the North Island from Northland to Whanganui, exhibited less genetic variability (COI gene) than S. janae, but also had geographically isolated haplotypes, suggesting limited dispersal. Both species had their greatest genetic diversity in Northland, which other workers have suggested was a likely refuge from Pleistocene glaciations and subsequently a source of recolonization further south. Overall the present study has expanded knowledge of the New Zealand Ephemeroptera by documenting patterns of species richness and community similarity in relation to latitude and altitude within the country, and provided new information and a better understanding of the distribution, ecology and conservation needs of poorly known species.
Auckland University of Technology MAppSci thesis, 2008
Technical reports by Stephen R Pohe
Unpublished technical report, 2022
Terrestrial amphipods (Crustacea: Amphipoda: Talitroidea) or landhoppers have often been overlook... more Terrestrial amphipods (Crustacea: Amphipoda: Talitroidea) or landhoppers have often been overlooked as research or conservation subjects in New Zealand. Currently, there are 28 native species of landhopper described from New Zealand. Information around their conservation needs is scant and only one species is currently assessed in the New Zealand Threat Classification System (NZTCS). There is an urgent need therefore to understand the conservation requirements of our native landhoppers. This report presents the recommended threat statuses for all 28 native landhopper species described from New Zealand. Recommendations for a further eight undescribed New Zealand species, as well as two introduced species, are also presented. Two species were assessed as being Threatened (both Nationally Vulnerable), and 11 taxa were classed as At Risk (two as Relict, and nine as Naturally Uncommon). Most native species fell into the Not Threatened and Data Deficient categories. Two species are listed as Introduced and Naturalised. All but one of the assessments were newly proposed listings for the NZTCS. The implications of the recommended rankings on research and management of landhoppers in New Zealand are discussed. Notably, serious knowledge gaps around the taxonomic status of many New Zealand landhoppers are impeding our ability to accurately determine appropriate threat statuses and conservation measures. A pending journal publication will therefore focus in more detail on the current state of the taxonomy.
Unpublished technical report, 2020
Conference posters by Stephen R Pohe
In late 2008 an unusual mayfly nymph was collected from a stony stream in the northernmost part o... more In late 2008 an unusual mayfly nymph was collected from a stony stream in the northernmost part of Northland, New Zealand. Additional nymphal, subimaginal and adult material resulted in the description by one of us (MJW) of a new species of Leptophlebiidae (Ephemeroptera) and a new genus, Aupouriella, erected to contain it. Aupouriella pohei, given the common name kanapa Karaaroa by the landowner of the type locality, is unique among New Zealand Ephemeroptera in that eyes of adult males are not divided into upper and lower portions, and that nymphs, subimagos and adults all have very slender legs. Little is known of the biology, ecology or distribution of this mayfly other than aspects of the physical environment of the sole stream in which the species was found, and the species of co-occurring stream invertebrates. The Department of Conservation Threat Classification System for aquatic invertebrates is currently being revised and A. pohei has been placed as Nationally Critical.
Duplicates for deletion by Stephen R Pohe
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Publications by Stephen R Pohe
Theses by Stephen R Pohe
Technical reports by Stephen R Pohe
Conference posters by Stephen R Pohe
Duplicates for deletion by Stephen R Pohe