Metrosideros Robusta Research Articles

Exploring the Chemical Properties and Biological Activity of Four New Zealand Monofloral Honeys to Support the Māori Vision and Aspirations.

Honey production and export are significant contributors to the Aotearoa New Zealand economy, generating over 400 million dollars in revenue. Its main export is mānuka (Leptospermum scoparium) honey, which has a high commercial value due to its medicinal properties that are linked to its unique chemical composition. The compound methylglyoxal (MGO) has been identified as the main floral marker and is used as a quality indicator, often labelled as unique mānuka factor (UMF). However, the high demand for mānuka honey creates pressure on beekeepers and may have negative ecological consequences by favouring extensive mānuka monocultures to the detriment of other native species. There are other honeys native to New Zealand, such as kāmahi (Weinmannia racemosa), kānuka (Kunzea ericoides), rātā (Metrosideros robusta) and rewarewa (Knightia excelsa), that also have medicinal properties; however, they are less well known in the local and global market. Indigenous Māori communities envision the production and commercialization (locally and internationally) of these honeys as an opportunity to generate income and secure a sustainable future in alignment with their worldview (Te Ao Māori) and values (tikanga Māori). Diversifying the market could lead to a more sustainable income for beekeepers and reduce pressure on Māori and the conservation land, while supporting indigenous communities to realize their vision and aspirations. This manuscript provides an extensive review of the scientific literature, technical literature and traditional knowledge databases describing the plants of interest and their traditional medicinal uses (rongoā) and the chemical properties of each honey, potential floral markers and their biological activity. For each honey type, we also identify knowledge gaps and potential research avenues. This information will assist Māori beekeepers, researchers, consumers and other stakeholders in making informed decisions regarding future research and the production, marketing and consumption of these native monofloral honeys.

Phytoremediation of microbial contamination in soil by New Zealand native plants

Novel research has demonstrated that the roots of some bioactive plants - called pathogen phytoremediation plants - enhance die-off of pathogenic organisms in the soil. Strategic establishment of pathogen phytoremediation plants may reduce the transport of human pathogens to water sources. Such plantings could be used in riparian margins, as buffer strips to protect drinking water supplies, or block planting in ‘critical source areas’ of microbial contamination, such as grazing paddocks, organic waste – including sewage sludge - amended land, animal feedlots and housing facilities, and manure storage areas. This work aimed to investigate the antimicrobial activity of a range of New Zealand native plants known for their antimicrobial potential from previous research or through indigenous knowledge, and to assess if any of them could potentially be used for pathogen phytoremediation. Two laboratory screening experiments demonstrated the antimicrobial activity of Leptospermum scoparium, including the local variety swamp mānuka, Kunzea ericoides, Pseudowintera colorata, and Metrosideros robusta against three human pathogens and two indicator organisms. A greenhouse experiment showed a 90% reduction of Escherichia coli numbers in dairy shed effluent irrigated pots after 14 days in soils under swamp L. scoparium and M. robusta, compared with 45 days in soil under Lolium perenne. The pH in the soil under swamp L. scoparium and M. robusta was significantly lower than under L. perenne, which could partially explain the faster E. coli reduction.

Deadwood in New Zealand's indigenous forests

We present the results of a systematic, unbiased national survey of deadwood volume and biomass in New Zealand's remaining indigenous forests based on an 8-km grid of 894 permanent plots. New Zealand's old growth evergreen temperate forests are largely comprised of long-lived, slow-growing tree species typically growing in cool, humid conditions; collectively these conditions are thought to promote accumulation of high deadwood stocks. We estimated deadwood biomass and volume in New Zealand's forests and compared these stocks with published values from other broadleaved evergreen temperate forests. Mean deadwood biomass in New Zealand was 54 Mg ha −1 but ranged across plots from 0 to 550 Mg ha −1. Mean deadwood volume was 158 m 3 ha −1 and ranged across plots from 0 to 1890 m 3 ha −1. Fallen logs accounted for 63% of total deadwood volume and 65% of total deadwood biomass, with standing dead trees being the remainder. Each piece of deadwood was classified into one of three broad decay classes and >40% of deadwood was fallen logs of the intermediate decay class. Deadwood biomass and volume varied 1.8- and 1.9-fold, respectively, among forest types and was greatest in broadleaved forests, dominated by Weinmannia racemosa (Cunoniaceae), Metrosideros umbellata (Myrtaceae) and Metrosideros robusta, and broadleaf- Nothofagus (Nothofagaceae) forests supporting the large tree species Nothofagus fusca. Deadwood biomass and volume were least in broadleaf-conifer admixtures. We used structural equation models to determine whether deadwood biomass could be predicted from climate and environment (vapor pressure deficit, elevation and slope), live tree biomass, forest composition (captured by two ordination axes), wood density of live trees, and tree size (a proxy for stand age). The model that best fit the data retained only vapor pressure deficit, live tree biomass and the first ordination axis as predictors of deadwood biomass. However, this model predicted just 2.4% of the variation in deadwood biomass, suggesting that additional factors not captured by this dataset, such as disturbance dynamics, may control deadwood abundance. Comparisons with other temperate and tropical forests did not support the hypothesis that New Zealand's cool temperate rainforests support higher than expected biomass or volume of deadwood.

Recent literature on lichens—213

Affeld, K., J. Sullivan, S. P. Worner & R. K. Didham. 2008. Can spatial variation in epiphyte diversity and community structure be predicted from sampling vascular epiphytes alone? Journal of Biogeography 35(12): 2274–2288. [Study in temperate rain forest of South Island, New Zealand, on epiphytes of Metrosideros robusta trees. Lichens ranged from 10–18% of the epiphytic flora. ‘‘Although we found some evidence that vascular plant seedling establishment was linked to the presence of lichens and the biomass of nonliving components in the epiphyte mats, there was no correlation in the spatial patterning or determinants of species richness between non-vascular and vascular plants.’’ There is no listing of the lichen species encountered.] Aptroot, A. & L. Sparrius. 2008. Crustose Roccellaceae in the Galapagos Islands, with the new species Schismatomma spierii. The Bryologist 111(4): 659–666. [Treatment of 24 spp. (many new records for the Galapagos and Ecuador); key. New: S. spierii n.sp. on coastal and inland trees. ‘‘Lecanographa laingiana is reported for the first time from the New World.’’ The genus Opegrapha was not included in this study.] Armaleo, D., Y. Zhang & S. Cheung. 2008. Light might regulate divergently depside and depsidone accumulation in the lichen Parmotrema hypotropum by affecting thallus temperature and water potential. Mycologia 100(4): 565–576. [A direct correlation was observed between the yearly amount of light reaching the lichen and the amount of atranorin. In contrast, the amount of norstictic acid decreased with increasing light.] Benatti, M. N. & M. P. Marcelli. 2007. Generos de fungos liquenizados dos manguezais do sul-sudeste do Brasil, com enfoque no manguezal do Rio Itanhaem, Sao Paulo. Acta Botanica Brasilica 21(4): 863–878. [Treatment of 81 genera (including a key) of lichens from mangrove forests in the region. In Portuguese with English abstract.] ——— & ———. 2008. Especies de Parmotrema (Parmeliaceae, Ascomycetes liquenizados) com maculas reticulares do litoral centro-sul do estado de Sao Paulo, Brasil. Hoehnea 35(1): 75–90. [Treatment (with key) of 6 spp. previously placed in the genus Rimelia. In Portuguese with English summary.] Berger, F. & A. Aptroot. 2008. Bactrospora flavopruinosa, a new lichen species from Bermuda. Lichenologist 40(6): 543–547. [New: B. flavopruinosa n.sp. from decorticated trunk of Juniperus bermudiana.] Bielczyk, U. 2005. Porosty w Tatrach. Pamietnik Polskiego Towarzystaw Tatrzanskiego [Memoir of the Polish Tatra Society] 14: 7–18. [General article on lichens of the Tatra Mountains, Poland. In Polish.] Bostock, P. & A. Holland. 2008. Appendix VIII: New names and taxa for Queensland plants, algae, lichens, bryophytes and fungi. July 2006 to June 2007. Pages 41–54. In A. Holland & P. Postock (eds.), Queensland Herbarium Achievements 2006–2007. Environmental Protection Agency, The State Government of Queensland. [Brief compiled report including 20 lichen spp.] Botting, R. S., J. Campbell & A. L. Fredeen. 2008. Contrasting arboreal and terrestrial macrolichen and bryophyte communities in old-growth sub-boreal forests of central British Columbia. The Bryologist 111(4): 607–619. [Authors analyzed biomass and nitrogen content in 71 spp. of macrolichens and 47 spp. of bryophytes in the study area NE of Prince George. ‘‘In total, terrestrial and arboreal lichens and bryophytes represented 20–39 kg N ha in this old-growth sub-boreal spruce ecosystem.’’] Bowker, M. A., G. W. Koch, J. Belnap & N. C. Johnson. 2008. Nutrient availability affects pigment production but not growth in lichens of biological soil crusts. Soil Biology and Biochemistry 40(11): 2819–2826. [Experiments with Collema tenax. ‘‘Although Mn fertilization does not appear likely to increase photosynthesis or growth of Collema, it could have a role in survivorship during environmentally * The cumulative database for this series is available in searchable form on the World Wide Web at http://www.nhm.uio.no/botanisk/bot-mus/ lav/sok_rll.htm. I owe special thanks to Bill Buck for providing copies of papers by other authors, which were otherwise unavailable to me, and to the cooperating authors who send reprints or electronic versions of their works to me for inclusion in this series.

The invertebrate fauna of epiphyte mats in the canopy of northern rata (Myrtaceae: Metrosideros robusta A. Cunn.) on the West Coast of the South Island, New Zealand

The range of microhabitats and microclimatic conditions provided by epiphytes has been linked to the high diversity of invertebrates in many forest canopies worldwide, but comparably little is known about the invertebrate fauna in this habitat in New Zealand. This study compiled an inventory of the invertebrate fauna of epiphyte mats in the canopy of northern rata (Myrtaceae: Metrosideros robusta A. Cunn.) at two study sites on the West Coast of the South Island. A total of 242 069 invertebrate specimens was collected over one year, representing 4 phyla, 9 classes and more than 160 families, 225 genera and 446 species. At least 10 new species and 3 new genera were identified, while 5 species were recorded outside their known geographical range. Epiphyte mats provided habitat for an invertebrate fauna, highly diverse and abundant both taxonomically and functionally, dominated in terms of abundance by Acari, Collembola and Hymenoptera (largely ants), and in terms of feeding guilds by epiphyte grazers and ants. As the first inventory of this taxonomic depth and breadth compiled for New Zealand forest epiphyte habitats, this study provides important baseline data for the conservation of biodiversity in New Zealand's indigenous forests.

Can spatial variation in epiphyte diversity and community structure be predicted from sampling vascular epiphytes alone?

AbstractAim Non‐vascular epiphytes have been largely ignored in studies examining the biotic and abiotic determinants of spatial variation in epiphyte diversity. Our aim was to test whether the spatial patterning of species richness, biomass and community composition across geographic regions, among trees within regions, and among branches within trees is consistent between the vascular and non‐vascular components of the temperate rain forest flora.Location Coastal lowland podocarp‐broadleaved forests on the west coast of the South Island of New Zealand.Methods We collected single samples (30 × 25 cm) from 96 epiphyte assemblages located on the inner branches of 40 northern rata (Metrosideros robusta) trees. For each sample, branch characteristics such as branch height, branch diameter, branch angle, branch aspect, and minimum and maximum epiphyte mat depth were recorded. The biomass for each individual epiphyte species was determined.Results Northern rata was host to a total of 157 species, comprising 32 vascular and 125 non‐vascular species, with liverworts representing 41% of all species. Within epiphyte mats, the average total organic biomass of 3.5 kg m−2 of branch surface area consisted largely of non‐living biomass and roots. Vascular and non‐vascular epiphytes showed strikingly different spatial patterns in species richness, biomass and composition between sites, among trees within sites, and among branches within trees, which could not be explained by the branch structural characteristics we measured. The two plant groups had no significant association in community composition (r = 0.04, P = 0.08). However, the species richness of vascular plant seedlings was strongly linked to the presence/absence of lichens.Main conclusions Non‐vascular plants contributed substantially to the high species richness and biomass recorded in this study, which was comparable to that of some tropical rain forests. High variability in community composition among epiphyte mats, and very low correlation with any of the environmental factors measured possibly indicate high levels of stochasticity in seed or spore colonization, establishment success or community assembly among branches in these canopy communities. Although we found some evidence that vascular plant seedling establishment was linked to the presence of lichens and the biomass of non‐living components in the epiphyte mats, there was no correlation in the spatial patterning or determinants of species richness between non‐vascular and vascular plants. Consequently, variation in total epiphyte biodiversity could not be predicted from the measurement of vascular plant diversity alone, which highlights the crucial importance of sampling non‐vascular plants when undertaking epiphyte community studies.

A new genus and species of felt scale (Hemiptera: Coccoidea: Eriococcidae) from epiphyte communities of northern rata (Metrosideros robusta Cunn.: Myrtaceae) canopy in New Zealand

The adult female, 2nd-instar female and 1st-instar nymph of a new genus and species of felt scale insect Affeldococcus kathrinae (Eriococcidae) are described from epiphyte mats in the high canopy of northern rata trees. The material was collected from two study sites on the west side of the South Island, New Zealand: Bullock Creek, Punakaiki, and at the start of the Heaphy Track near Karamea. This new species is unlike any others in the New Zealand fauna and apparently shares convergent features with the cactus-feeding Dactylopius species (Dactylopiidae), and possibly some relationship with the Australian genus Phacelococcus Miller. An additional couplet is provided to include this new genus in the key to genera of Eriococcidae present in New Zealand.

C-Methyl-flavonoids from the leaf waxes of some Myrtaceae

The thin waxy coatings on leaves of nine species of Callistemon, two of Melaleuca and one species of Metrosideros, have been studied for the occurrence of leaf surface flavonoids. The Callistemon species and Metrosideros robusta exhibit only C-methylated flavonoids, while O-methyl flavonoids were detected in Melaleuca huegelii. The new natural C-methyl flavonol, 5,7-dihydroxy-3,8,4′-trimethoxy-6-C-methylflavone, was isolated from Metrosideros robusta. The leaf wax of Callistemon coccineus contains the novel C-methylflavonoid, 5,4′-dihydroxy-8-C-methyl-7-methoxy flavanone.

Establishment patterns and host tree preferences of the emergent hemi‐epiphytic tree Metrosideros robusta in northern New Zealand

The relative importance of terrestrial and epiphytic establishment of the emergent tree Metrosideros robusta (Myrtaceae) and its host tree species and sizes, were surveyed in seven different forest types with different disturbance histories in northern New Zealand. At two disturbed sites, M. robusta established terrestrially. At less disturbed sites, most M. robusta were hemi‐epiphytic, but terrestrially established individuals had colonised occasional canopy gaps. M. robusta occurred more commonly on large host trees (>50 cm diameter) than either relative density or relative basal area of host trees would predict, suggesting that large trees are intrinsically better places to establish and not just bigger targets. M. robusta grew on 20 of the 42 tree species sampled. Vitex lucens, dead trees, and the podocarps Dacrydium cupressinum, Dacrycarpus dacrydioides, and Prumnopitys ferruginea were more common as hosts than their relative densities predicted at all sites where they were present. Other host species such as Podocarpus hallii and Laurelia novae‐zelandiae were “preferred” at some sites, but not at others. M. robusta tended to establish in different sites on different host tree species. Hauturu (Little Barrier Island), where the Australian brushtail possum (Trichosurus vulpecula) has never been present, had the highest number of saplings and fewest dead M. robusta, suggesting that this introduced browser is changing the size structure of mainland New Zealand M. robusta populations.

Effects of possum browsing on northern rata, Orongorongo Valley, Wellington, New Zealand

Browse damage to northern rata (Metrosideros robusta) caused by brushtail possums (Trichosurus vulpeculd) was measured on 24 trees in the Orongorongo Valley, near Wellington, in 1970–74. Fifteen of the same trees were re‐assessed annually for browse damage and defoliation in 1990–94. Resurveying allowed a check on mortality since 1974 and an opportunity to assess the importance of natural fluctuations in possum density and their impacts on northern rata. Since 1970, possum density has fluctuated between 6 and 12 possums ha‐1, the latter in 1990 being the highest level since 1966. In 1990 all 21 trees surviving in 1974 were still alive, and the 15 trees in this survey showed nil‐to‐light possum browse. By 1994, one tree had been wind damaged, 7 showed heavy browse damage and extensive defoliation, and 7 still showed only light browse. The extent of possum damage varied markedly between years, and from tree to tree, but overall damage levels increased progressively from 1990 to 1994 while possum density remained consistently above the long‐term average. This study has reinforced Meads's (1976) findings that possums are the main cause of decline in numbers of northern rata, but does not confirm Meads's prediction of ongoing high mortality. The high level of mortality in 1970–74 and the increasing levels of damage seen in 1990–94 seem to result from a combination of periods of above‐average possum numbers and other stress factors such as drought.

An interglacial macrofossil flora from Schulz Creek, north Westland, New Zealand

On a raised shoreline assumed to be of early Kaihinu Interglacial age (more than 100 kyr ago), in north Westland, well-preserved plant fossils are exposed in sediments in a road-cutting. They were probably deposited in a small freshwater lagoon behind a beach ridge, on a prograded shore. The fossils are robust (wood, coriaceous leaves, tough fruit, or seeds); almost certainly they represent only a proportion of the flora in Schulz Creek catchment at the time. The species composition (including Dacrydium cupressinum, Podocarpus hallii, Prumnopitys ferruginea, small conifers, Nothofagus spp., Metrosideros robusta, Elaeocarpus dentatus) suggests that the climate when the deposit was laid down was probably as mild as it is now. Most of the plant species of the fossil flora occur today in Schulz Creek catchment and the remainder live nearby.

The pre-Taupo eruption (c.AD 130) forest of the Benneydale-Pureora district, central North Island, New Zealand

Abstract The composition and structure of three small areas of west Taupo forest, blasted down and buried during the c. AD 130 Taupo tephra eruption, are revealed by analysis of plant macrofossils, including leaves, seeds and wood. Data from these three sites and from the recently described Pureora buried forest were then used to interpret the pre-eruption vegetation along a 20 kilometre transect, from Pureora westward to Benneydale. All the stands were on flat or undulating terrain and dominated by podocarps, ranging from rimu (Dacrydium cupressinum)-tanekaha. (Phyllocladus trichomanoides) at Pureora to rimu at Benneydale. Broadleaved trees increased westward; on lower hillslopes in the Benneydale buried forest, northern rata (Metrosideros robusta) was an important canopy component. An amelioration of climate with decreasing altitude westward was indicated by a gradual change from prominence of horopito (Pseudowintera colorata) at Pureora to P. axillaris at Benneydale, and the presence of rewarewa (Knigh...

The Daily Course of Water Potential and Leaf Conductance in some New Zealand Plants

The field water potentials of some 23 species, mostly woody plants and ferns native to New Zealand (but including one introduced fern), were measured on various occasions, mostly during the 1982/83 summer. The minimum water potentials recorded in the field were highly correlated with the ability of cut shoots and leaves to avoid low water deficits and low water potentials when artificially desiccated in the laboratory. Species that maintained high water potentials in the field also showed lesser fluctuations in water potential than those that developed low water potentials. Leaf conductances and transpiration rates were measured in five species. Low conductances and transpiration rates were generally associated with those species that maintained high water potentials in the field (e.g. Phymatosorus diversifolius (W illd .) P ic . S er .), whereas high conductances and transpiration rates were generally associated with species that developed low water potentials (e.g Brachyglottis repanda F orst .). One species, Metrosideros robusta A. C unn . showed high conductances and transpiration rates but maintained a higher water potential in the field. Those species that showed the largest reductions of conductance in the early afternoon also showed the best recovery of shoot water potential. For the species examined, the artifical desiccation of cut shoots and leaves in the laboratory provides a guide to minimum water potentials in the field. These appear to be determined by rates of water loss from the shoot rather than the hydraulic conductivity of the soil-plant-atmosphere system.

Diet of the opossumTrichosuvus vulpecula(Kerr) in the Orongorongo Valley, Wellington, New Zealand, in relation to food‐plant availability

The food preferences of a population of opossums in 4.4 ha of lowland broadleaf/podocarp forest were studied for 4 years by faecal analysis. A survey and phenological records were made of the vegetation to compare foods eaten with foods available. Metrosideros robusta and Weinmannia racemosa contributed 60% to the leaf diet, and were being defoliated and killed by opossums. Metrosideros fulgens and Ripogonum scandens, both lianes, together contributed 15 % to the leaf diet but were eaten seasonally. About 10 other species contributed small amounts. Flowers, flower buds, fruit, seeds, bark, and petiole made up about 35 % of the total diet. Compared with their status in the same area 30 years ago, Fuchsia excorticata, Alectryon excelsus, Pseudopanax arboreum, Myrsine salicina, and Coriaria arborea are now rare or localised and of much less consequence in the diet.

Effects of opossum browsing on northern rata trees in the Orongorongo Valley, Wellington, New Zealand

Browsing damage caused by opossums (Trickosurus vulpecula) was assessed visually, against a simple index, on 24 northern rata trees (Metrosideros robusta A. Cunn.) every 2 months from November 1969 to November 1974. All 24 trees showed some damage, and 3 died as a result of continued heavy browsing; 7 of 26 other rata trees in the study area have died similarly since 1969. When opossums were excluded from 5 previously browsed trees, all recovered. Stick insects (Phasmatidae) contributed about 3% to the total damage, but with other defoliating insects may be more important in other parts of New Zealand.

THE CASTLE HILL BASIN.

CORRIGENDA. Professor V.J. Chapman has written to the Editor asking that two items be emended in his article, ‘The Geographical Status of New Zealand Lowland Forest Vegetation’ which was published in the New Zealand Geographer, Volume 14, Number 2, October 1958. On page 106, Metrosideros umbellata in line I should read Metrosideros robusta whilst P. nivalis in line 17 should read P. hallii.