A new record of Percursaria percursa (Ulvaceae, Ulvales) on the North Island, New Zealand

The filamentous green alga Percursaria percursa (Ulvaceae, Ulvales) was recorded for the first time on the North Island of New Zealand at mokoroa Estuary, Tauranga Harbour. This species is previously known within New Zealand from only two records, both from the South Island. In Tauranga Harbour, this species was restricted to anoxic estuarine sediments where mangrove forests had been mulched, and mulchate left in situ. Percursaria percursa was found intertwined with Ulva spp. and Rhizoclonium spp. Surveys of other North and South Island estuaries suggest that this alga, although occurring as part of nuisance green algal blooms in Tauranga Harbour, has only colonized human-impacted locations, and has not yet been observed in natural' estuarine ecosystems in New Zealand. As this species was found intertwined with other mat-forming filamentous green algae, it can easily be misidentified in the field, leading to both over- and under-reporting of species occurrence

Barcoding of the cytochrome oxidase I (COI) indicates a recent introduction of Ciona savignyi into New Zealand and provides a rapid method for Ciona species discrimination

Mitochondrial cytochrome oxidase I (COI) gene sequencing (DNA barcoding) of Ciona specimens from New Zealand (NZ) led to the first record of the solitary ascidian Ciona savignyi in the Southern Hemisphere. We sought to quantify C. savignyi COI genetic diversity around the NZ archipelago and to compare this with diversity within C. savignyi's native range in the north-west Pacific. Ciona savignyi specimens were collected from two NZ sites and from three sites around Japan. COI sequences (595 bp) were amplified and measures of genetic diversity were calculated. Based on differences between their COI sequences we developed a PCR-based assay to distinguish C. savignyi from the morphologically similar C. intestinalis. A total of 12 C. savignyi COI haplotypes were recovered from the 76 samples. Of the four haplotypes observed in NZ, two were unique. From the 10 haplotypes observed in the Japan samples, eight were unique. The C. savignyi populations in Japan were found to contain higher haplotype diversity when compared with those in NZ. The NZ samples contained only a small subset of the haplotype variation of the Japan samples, however, NZ samples did harbor two haplotypes not observed in the Japan samples. A PCR-based assay developed from the COI sequences was able to reliably discriminate the two Ciona species. The low COI genetic diversity within the two NZ C. savignyi populations sampled is consistent with a founder effect associated loss of genetic diversity. The robust PCR-based assay for distinguishing C. savignyi and C. intestinalis may find application in ecological and taxonomic studies and can be applied to both archival materials and live animals

Are current ecological restoration practices capturing natural levels of genetic diversity? A New Zealand case study using AFLP and ISSR data from mahoe (Melicytus ramiflorus)

Sourcing plant species of local provenance (eco-sourcing) has become standard practice in plant community restoration projects. Along with established ecological restoration practices, knowledge of genetic variation in existing and restored forest fragments is important for ensuring the maintenance of natural levels of genetic variation and connectivity (gene flow) among populations. The application of restoration genetics often employs anonymous ‘fingerprinting’ markers in combination with limited sample sizes due to financial constraints. Here, we used two such marker systems, AFLPs and ISSRs, to estimate population-level genetic variation of a frequently used species in restoration projects in New Zealand, māhoe (Melicytus ramiflorus, Violaceae). We examined two rural and two urban forest fragments, as potential local source populations, to determine whether the māhoe population at the recently (re)constructed ecosystem at Waiwhakareke Natural Heritage Park (WNHP), Hamilton, New Zealand reflects the genetic variation observed in these four potential source populations. Both marker systems produced similar results and indicated, even with small population sizes, that levels of genetic variation at WNHP were comparable to in situ populations. However, the AFLPs did provide finer resolution of the population genetic structure than ISSRs. ISSRs, which are less expensive and technically less demanding to generate than AFLPs, may be sufficient for restoration projects where only a broad level of genotypic resolution is required. We recommend the use of AFLPs when species with a high conservation status are being used due to the greater resolution of this technique

Diet selectivity in a terrestrial forest invertebrate, the Auckland tree wētā, across three habitat zones.

Insects are important but overlooked components of forest ecosystems of New Zealand. For many invertebrate species, information on foraging patterns and trophic relationships is lacking. We examined diet composition and selectivity in a large bodied invertebrate, the Auckland tree wētā, in three habitat zones in a lowland New Zealand forest. We asked if Hemideina thoracica selectively forage from available plant food sources, and if these choices were lipid-rich compared to non-preferred available plants. We also identified the proportion of invertebrates in their frass as a proxy for omnivory. From reconnaissance plot sampling, together with faecal fragment analysis, we report that more than 93% of individual wētā had eaten other invertebrates before capture. Wētā in the highest elevation hillslope habitat consumed significantly fewer plants on average than wētā on either the low elevation terrace or mid-slope habitat. Hillslope wētā also had the highest average number of invertebrate fragments in their frass, significantly more than wētā in the low elevation terrace habitat. Wētā showed high variability in the consumption of fruit and seeds across all habitats. Generally, we did not observe diet differences between the sexes (although it appears that male wētā in the mid hillslope habitat ate fruits and seeds more voraciously than females), suggesting that the sexes have similar niche breadths and display similar degrees of omnivorous behaviour. Extraction of leaf lipids demonstrated a range of lipid content values in available plants, and Ivlev’s electivity index indicated that plant species which demonstrated high electivity, tended to have higher concentrations of lipids in their leaves. Our findings indicate that H. thoracica forage omnivorously and selectively, and hence play multiple roles in native ecosystems and food webs

Above the treeline: a nature guide to alpine New Zealand [Book review]

This article reviews the book "Above the treeline: a nature guide to alpine New Zealand", by Sir Alan F. Mark (with contributors)

Genetic variability of New Zealand seagrass (Zostera muelleri) assessed at multiple spatial scales

We conducted RAPD analyses at multiple spatial scales to contribute to the conservation and future restoration of New Zealand's seagrass, Zostera muelleri Irmisch ex Asch. (Zosteraceae). Initially we focused on fine-scale genetic variation within two estuaries on the North Island, one on the East coast the other on the West coast. Within each estuary individuals were genetically similar, however, there was clear genetic separation between the two sites (genetic distance D = 0.2965). Genetic variation within a sampling location (m scale) was similar to that observed among sampling locations (km scale) within a site (21% and 28%, respectively) and smaller than that observed between sites (51%). We then expanded our sampling to include a further six populations distributed across almost the entire latitudinal (ca. 15°) gradient of the North and South Islands. At this scale genetic differences were closely correlated with coastal currents. There was a clear separation between North Island and South Island populations and further separation between the East and West coast populations of each Island. Sites located along the same section of coastline were more genetically similar than those from the opposite coast and other Island. Genetic similarity was highest within each of the sites, indicating a low degree of gene flow between populations. We recommend that any future restoration and conservation projects use only locally eco-sourced materials for population augmentations

Biological flora of New Zealand 13. Pittosporum cornifolium, tāwhiri karo, cornel-leaved pittosporum

A comprehensive review of the morphology, anatomy, taxonomy, chemistry and ecology of the endemic New Zealand facultative shrub epiphyte Pittosporum cornifolium (Pittosporaceae) is presented. Strong habitat specificity restricts this species to lowland forest and coastal habitats, which are widely yet discontinuously distributed north of latitude 42°15′S. Pittosporum cornifolium is typically associated with old growth forest systems and low nutrient substrates, with low mean daily temperatures in the coldest month (0.5 kPa) apparently restricting its distribution. Significant morphological variability is evident in leaves and flowers, especially with respect to plants from the Poor Knights Islands. Genetic analyses of five mainland populations and individuals representing Poor Knights Islands populations revealed relatively low genetic diversity at the population level which is likely to be the result of geographic isolation. Molecular phylogenetic studies suggest a New Caledonian origin for the species with close affinities to both P. pimeleoides subspecies. Several lines of evidence suggest recognition of the Poor Knights Islands entity as a new taxon. However, analysis of additional morphological, reproductive and molecular data across the full geographic range will be required to confirm current inferences. Although populations have declined, P. cornifolium is not currently threatened, however, it should be considered for reintroduction to sites in districts where its range has been severely reduced

Data from: A new species of Pittosporum described from the Poor Knights Islands, Northland, Aotearoa/New Zealand

Here we describe Pittosporum roimata Gemmill & S.N. Carter, the only vascular plant endemic to the Poor Knights Islands, Northland, Aotearoa/New Zealand. This new species has previously been referred to as a distinct variant of Pittosporum cornifolium (tāwhiri karo, wharewhareatua), a morphologically similar epiphytic shrub known from both main islands of New Zealand as well as other off shore islands. We have segregated this new species from P. cornifolium based on morphology, DNA sequence variation, as well as distribution. Pittosporum roimata is distinguished from P. cornifolium by a number of characters, including having larger thicker leaves with shorter petioles, flowers with yellow petals, larger inflorescences, and producing several terminal fruits per stem. Pittosporum roimata is locally common on the islands of Tawhiti Rahi, Aorangi, and Aorangaia, growing on rocky substrates associated with Xeronema callistemon (raupo taranga) and Metrosideros excelsa (pōhutukawa). Using the current New Zealand Threat Classification System, we suggest a preliminary classification of this new species as 'At Risk / Naturally Uncommon' qualified DP [Data Poor), OL [One Location]

New Zealand seagrass – More threatened than IUCN review indicates

A recent article describing an extinction risk assessment of the world’s seagrass species (Short et al., 2011) assigned New Zealand’s only seagrass species, Zostera muelleri, to the IUCN Red List category of ‘Least Concern’. We are concerned that this assignment does not reflect the true status of Z. muelleri in New Zealand (one of three countries where this species occurs) and that such a categorisation will detract from efforts to prevent further decline of this species

Testing broadcast seeding methods to restore urban forests in the presence of seed predators

Forest restoration in urban areas often occurs in isolation from remnant forest, limiting the chances for recolonization by native species. Plants with bird-dispersed seeds can be particularly vulnerable to dispersal limitation and regeneration can be further impeded by non-native seed predators. We used a factorial experiment to investigate broadcast seeding as a method to reintroduce trees with large seeds and fleshy fruits into early successional forests. We assessed rates of seed and fruit loss, germination and seedling establishment in three seed treatments: (1) caging to exclude introduced mammalian seed predators; (2) removal of fleshy fruit pericarp; and (3) placing seeds in nutritionally enriched clay balls. Across all species (Beilschmiedia tawa, Elaeocarpus dentatus, and Litsea calicaris) seeds and fruits accessible to mammalian predators suffered significantly greater loss (58%) than those protected by cages (4%). However, seed and fruit loss in the presence of predators was reduced to only 35% across all species by the treatment combining the removal of fruit flesh and clay ball application to seeds. Establishment of B. tawa seedlings after 1 year was significantly enhanced by the clay ball treatment (12% of seeds sown vs. 6% without clay balls). Very low establishment rates were recorded for E. dentatus and L. calicaris. Broadcast seeding was found to be a viable method of improving regeneration of large-seeded late successional trees and may be a cost-effective alternative to planting saplings. Seedling establishment can be improved with fruit flesh removal and clay ball treatments, especially in the presence of mammalian seed predators