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Premise of the study: Primers were developed to amplify low-copy nuclear genes in Hawaiian Metrosideros (Myrtaceae). Methods and Results: Data from a pooled 454 Titanium run of the partial transcriptomes of four Metrosideros taxa were used to identify the loci of interest. Ten exon-primed intron-crossing (EPIC) markers were amplified and sequenced directly with success in Metrosideros, as well as in a representative selection of Myrtaceae, including Syzygium, Psidium, and Melaleuca for most of the markers. The loci amplified ranged between 500 and 1100 bp, and up to 117 polymorphic sites were observed within an individual gene alignment. Two introns contained microsatellites in some of the species. Conclusions: These novel primer pairs should be useful for phylogenetic analysis and population genetics of a broad range of Myrtaceae, particularly the diverse fleshy-fruited tribes Syzygieae and Myrteae.

To gain understanding about invasive species physiology and also potential water conservation strategies, we investigated tree-level water use following a woody invasive removal experiment in Hawaii. Invasives had much higher water use rates than the native tree species, and stand level water use decreased by ∼50% after invasive removal., While the supply of freshwater is expected to decline in many regions in the coming decades, invasive plant species, often ‘high water spenders’, are greatly expanding their ranges worldwide. In this study, we quantified the ecohydrological differences between native and invasive trees and also the effects of woody invasive removal on plot-level water use in a heavily invaded mono-dominant lowland wet tropical forest on the Island of Hawaii. We measured transpiration rates of co-occurring native and invasive tree species with and without woody invasive removal treatments. Twenty native Metrosideros polymorpha and 10 trees each of three invasive species, Cecropia obtusifolia, Macaranga mappa and Melastoma septemnervium, were instrumented with heat-dissipation sap-flux probes in four 100 m2 plots (two invaded, two removal) for 10 months. In the invaded plots, where both natives and invasives were present, Metrosideros had the lowest sap-flow rates per unit sapwood, but the highest sap-flow rates per whole tree, owing to its larger mean diameter than the invasive trees. Stand-level water use within the removal plots was half that of the invaded plots, even though the removal of invasives caused a small but significant increase in compensatory water use by the remaining native trees. By investigating the effects of invasive species on ecohydrology and comparing native vs. invasive physiological traits, we not only gain understanding about the functioning of invasive species, but we also highlight potential water-conservation strategies for heavily invaded mono-dominant tropical forests worldwide. Native-dominated forests free of invasive species can be conservative in overall water use, providing a strong rationale for the control of invasive species and preservation of native-dominated stands.

Cladistic analyses are presented of matK sequence data as well as a nonmolecular database for an identical set of exemplar species chosen to represent the core genera or groups of genera in Myrtaceae. Eleven robust clades are recognized on the molecular data. Polyphyly of the previously recognized Metrosideros and Leptospermum alliances is confirmed, and several smaller informal taxonomic groupings are recognized from among the members of the former alliance, i.e., the Tristania, Tristaniopsis, Metrosideros, and Lophostemon groups. The nonmolecular analysis provides only limited resolution of relationships. A degree of congruence exists between the two analyses in that two separate fleshy-fruited clades, the Acmena and Myrtoid groups, are identified, as are the Eucalypt and Tristania groups, and Psiloxylon and Heteropyxis are the first lineages to diverge in both analyses. A combined analysis recognized all 11 clades that received strong support from the molecular data. A high level of homoplasy is revealed in many of the nonmolecular characters when they are examined against the combined estimate of phylogeny.

A new species, Uncinia perplexa, is described from the Surville Cliffs, Northland, New Zealand. Uncinia pelplexa has leaves 2–5 mm wide, 15–24 fernale florets per ‘Pike, the utric1es are glabrous, ovate, and have a conspicuous beak, and the female glumes are membranous and deciduous. Uncinia perplexa occurs naturally Only On u1tramafic soils where it grows under Metrosideros excelsus forest. The chromosome number is 2n = 12x = 132, and this is a new number for Uncinia. Information is provided on the species habitat, distribution, abundance, and conservation status.

The yield, composition and fragrance of the essential oils of seven Metrosideros species, which are endemic to New Zealand, were examined by GC-MS. Their composition clearly divided the species into two groups. Group I oils (M. carminea, M. perforata, M. robusta and M. umbellata) contained abundant levels of monoterpenes (28–58%), while group II oils (M. diffusa, M. excelsa and M. fulgens) did not (0–2%). All species contained a large number of sesquiterpenes. The composition of the oil of each species had characteristic elements. The oil yields were low and their fragrances had no outstanding features.

Vizella metrosideri sp. nov. is described and illustrated from Metrosideros excelsa. It forms macroscopically indistinct colonies either within or beneath the cuticle on the upper surface of living leaves. The colonies comprise fruiting bodies of the teleomorph and anamorph, together with a sparse network of flattened, ribbon‐like hyphae with thickened, dark septa and alternating dark and light cells. Such hyphae are characteristic Of the genus. The distinction between Vizella and Entopeltis is discussed.

New Zealand pohutukawa (Metrosideros excelsa), a member of the Myrtaceae, is a large, mass-flowering tree endemic to northern New Zealand coastlines. Mainland populations have been reduced to fragmented stands, and the original suite of bird pollinators has been largely replaced by introduced species. The native pollinator fauna on several offshore islands is largely intact and includes three species of the New Zealand honeyeaters (Meliphagidae) and native, solitary bees. We estimated multilocus outcrossing rates for three mainland and two island populations and found that they were among the lowest in the Myrtaceae (t(m) = 0.22-0.53). The shift in pollinators had no measurable effect on the mating system. Mass-flowering facilitates geitonogamous selfing, and inbreeding depression in seedling height was detectable at 6 mo of growth. F(s) [Wright's (1965) Fixation Index] was consistently higher than F(m) in all populations, indicating that selection may eliminate selfed offspring from populations prior to achieving reproductive maturity. Results suggest that increased selfing in mainland populations due to pollinator changes is not responsible for current patterns of poor regeneration of this species.

Metrosideros bartlettii (Myrtaceae) is a distinctive and extremely rare tree, endemic to New Zealand, first discovered in 1975. Prior to this study, a total of 19 adult individuals of the species had been reported; these are located in three small forest remnants in the far north of the North Island of New Zealand. Here we describe a total of 31 adult M. bartlettii at the three sites, including 12 individuals newly discovered by us. We analyse the genetic diversity of the species, using microsatellites to examine the chloroplast genome and amplified fragment length polymorphisms (AFLPs) to monitor nuclear variation. The results clearly demonstrate that M. bartlettii is a unique species, distinct from its two closest relatives M. robusta and M. excelsa. Analysis of genetic diversity within the 31 remaining individuals of M. bartlettii showed an average heterozygosity (H) of 0.18 and a proportion of polymorphic genes (P) of 0.44. Population structure, as shown by 286 AFLP loci, varied between the three geographical sites; the site with fewest individuals, containing two trees, showed some separation from the populations at the other two locations. These two latter sites, by contrast, had highly overlapping AFLP population diversity profiles. The implications of these results for conservation of the species are discussed.

We recorded the times of flowering, fruiting, and leafing for ten native canopy and subcanopy trees and shrubs (monthly from December 1994 through December 1997) in a montane cloud forest with relatively aseasonal rainfall on the island of Maui, Hawaii. These species represented the great majority of individual woody plants at the site. Flowers and fruits were available in the community year-round; however, all species exhibited annual patterns of flowering, and four species showed annual patterns of fruiting while the rest fruited in supra-annual patterns. Many species had protracted flowering or fruiting peaks, and some bore small numbers of flowers or fruit year-round. Most species flowered in a monthly peak mainly between May and August, corresponding to the period of greatest solar irradiance and marginally higher temperatures. Fruit ripening followed at varying intervals. In contrast, the heaviest flowering occurred between November and March, resulting from bloom of the dominant tree, Metrosideros polymorpha. At the highest elevations, Metrosideros flowering was heaviest during September, but peak flowering of lower elevation trees occurred in late fall and winter. Two forms of this species differed in their temporal and spatial patterns of flowering. For M. polymorpha var. polymorpha and var. incana, bloom peaked annually between November and January; however, for M. polymorpha var. glaberrima, flowering peaked from April through July, with an earlier secondary peak in January.

We have identified two new species of Metrosideros subg. Mearnsia (Myrtaceae) growing on, and apparently endemic to, the massif known as the Roches d’Ouaïème in New Caledonia. Of these two species, we include M. whitakeri in sect. Mearnsia and M. rotundifolia in sect. Calyptropelala. Both morphological assessments and phylogenetic analyses based on nrDNA sequence variation produced congruent interpretations of the novelty of the new species and of their classification.

An annotated list is presented of all fungi known to be associated with indigenous species of Metrosideros in New Zealand. This includes information on 209 species of fungi, with records taken from the literature, as well as unpublished information associated with specimens held in Herbarium PDD and in Herbarium NZFRI(M). There are relatively few primary pathogens or other fungi specifically associated with Metrosideros. Some secondary pathogens may play a role in dieback of Metrosideros spp., especially following possum browsing. Many wood‐rotting basidiomycetes and other saprobes are included. A few endophytic fungi have been isolated from symptomless leaves. Some non‐specific vesicular‐arbuscular mycorrhizal fungi are listed, but mushroom‐like fungi are rarely recorded as Metrosideros does not form endotrophic mycorrhizal associations.

The pollen and spores from surface samples consisting of moss polsters and soils collected from 15 sites in Northland and Rangitoto Island were analysed. Sample sites were chosen to be representative of differing plant communities in the Northland region. Major plant communities could be distinguished by their characteristic pollen spectra but minor associations were difficult to distinguish. Gymnosperms (anemophilous) are generally proportionately or over‐represented compared with zoophi‐lous taxa. A notable exception to this is Agathis australis which is typically grossly under‐represented. Angiosperm elements of Northland forests are generally very poorly represented, the exception being Metrosideros spp. which are either well or over‐represented. In contrast to reports from other parts of New Zealand, moderate to high values (>5%) of Nothofagus subgenus Fuscospora pollen in Northland spectra suggest local presence. Poaceae pollen records only low frequencies in forest spectra, but dominates g...

We developed 15 polymorphic microsatellite loci from the Hawaiian tree Metrosideros polymorpha. These loci were screened against two varieties from several populations and from 23 individuals from one mid-elevation population on Hawaii Island. Loci were variable with the number of alleles per locus ranging from three to 24. Polymorphic information content ranged from 0.222 to 0.941, and observed heterozygosity ranged from 0.261 to 0.955.

Summary. The type specimen of Metrosideros regelii is discussed. It contains a mixture of two species, representing different genera, and a lectotype is chosen. The generic position of the species is considered in the light of morphology and recent molecular evidence and the new combination, Mearnsia regelii, made.

Summary Dicranopteris linearis (Gleicheniaceae), a native fern common throughout the Old World tropics and Polynesia, forms dense thickets > 3m deep over large areas of open-canopy, oligotrophic, wet Hawaiian rainforests. Our objectives were to identify leaf- and whole plant-level traits that are key to its success and to determine its community-and ecosystem-level consequences in primary successional sites. Along an elevational gradient from 90 to 1660m, mean maximum net assimilation rates of Dicranopteris ranged from 2.9 to 5.0 μmol m−2 s−1, compared with 3.6–9.5 μmol m−1 s−1 in the codominant tree Metrosideros polymorpha. Gas-exchange characteristics did not explain Dicranopteris' success, nor its trends in production. However, indeterminate, clonal growth form, shallow rhizomes, marcescent leaves with low decomposability, and a mat-forming capacity enabled Dicranopteris to colonize sites and to maintain dominance via high effective leaf area, despte its low biomass. Phosphorus use efficiency, which reached 24 kg g−1, was exceptionally high, allowing colonization of phosphorus-poor sites. Dicranopteris contributed up to 74% of above-ground net primary productivity in a site where it contained only 14% of live biomass. It accounted for up to 57% and 47% of total nitrogen and phosphorus uptake by plants, respectively, where it contained only 24% and 30% of plant nitrogen and phosphorus. Dicranopteris leaves are short-lived and slow to decompose; thus, fixed carbon is transferred quickly to soil detrital pools where it contributes to aggrading soil organic matter pools and may exacerbate oligotrophic conditions, thereby strongly influencing soil genesis and ecosystem development. The fern therefore influences forest-floor light regimes and directs later community development. An exclusion experiment demonstrated that Dicranopteris competed with Metrosideros, but lack of revegetation in 40% of the exclusion area after 39 months showed that Dicranopteris also colonized microenvironments unavailable to its endemic codominants. Dicranopteris may play an important role in resisting invasions of exotic species into Hawaiian rainforests.

Non-native perennial grasses form 30% of the live understory biomass in seasonally dry, submontane forests in Hawaii Volcanoes National Park, yet their effects on native species are unknown. We removed these grasses from plots of 20 m × 20 m in 1991 and maintained removal and control areas over the next three years. Two fast growing shrub species, Dodonaea viscosa and Osteomeles anthylidifolia, increased in size significantly more in removal areas than in controls. Individuals of the most abundant shrub species, Styphelia tameiameia showed no net growth response to grass removal. They did, however, change their architecture: many branches along the mid and upper sections of the main trunk died and a proliferation of new leaves and shoots occurred in the lower 40 cm of trunk. Basal diameter increase was very small in Metrosideros polymorpha, the dominant tree species in these sites. All species except Styphelia had significantly increased leaf tissue nitrogen in removal plots by 18 months after removal when compared to shrubs in control areas suggesting that removal plot shrubs had greater access to soil nitrogen. Available soil-N pools, which were generally higher in the removal plots, support this interpretation. Light levels near the soil surface were also higher where grasses were removed than where they were present which may have contributed to increased shrub growth. By contrast, soil moisture was consistently lower where grasses were removed than where they were still present. Shrub tissue carbon isotope values were consistent with the interpretation that shrubs in removal plots had less rather than more water available to them. Hence, the increased growth observed in removal plot shrubs could not be due to release from moisture competition. Lastly, our results showed that seedlings of all woody species except Metrosideros were significantly more abundant in removal plots at both one and three years after removal and initially high sapling mortality was balanced by high recruitment into the sapling class. We believe that over time this will result in increased densities of native shrubs if grasses are kept out. With the presence of grasses, shrub growth in these woodlands is reduced and biomass is shifting towards grasses.

An earlier study suggested that soils on the windward slope of Mount Haleakala are excessively waterlogged at low altitudes but become better drained upslope. We analyzed altitudinal changes in soil N turn over, vegetation mass, and foliar chemical composition of the dominant canopy species, Metrosideros polymorpha (Myrtaceae), on this slope. The basal areas and DBH2× height (an index for volume) of woody species ≥2 m in height increased with altitude (as opposed to a general trend elsewhere), peaked at 1800 m elev., and abruptly declined above this altitude. Foliar N and P concentrations of Metrosideros showed a similar altitudinal trend with DBH2× height values. Foliar Fe and Al concentrations steadily increased downslope, but were low again at 450 m, the lowest altitude, contrary to expectation based on waterlogging. Toxic forms of Fe and Al may retard root penetration in waterlogged soils and thus the uptake of these elements. The net N mineralization rate for topsoils incubated in situ was 78.6 μg/g/20d at 1800 m elev., while small amounts of N were immobilized at 450, 1200 and 2200 m elev. The net N mineralization rates of the topsoils, which were air-dried to their permanent wilting points and incubated at 26°C, were greater than those of the wet samples at 26°C, only for the lowest altitude. Conversely, the net N mineralization rates of the topsoils which were kept wet and incubated at the higher temperature of 26°C were greater (P < 0.1) than those of the in situ wet samples only for 1800 m elev. The rates were the same for 450 and 2200 m elev. where the soils were waterlogged and very dry, respectively; thus, N turn over was more strongly limited by moisture than by temperature in these cases. Nutrient availability improved with altitude up to 1800 m elev. in association with the moisture gradient, and appeared to be responsible for the observed pattern in vegetation mass.

The native tree Metrosideros polymorpha dominates Hawaiian forests across a very wide range of soil fertility, including both sites where forest production is limited by nitrogen (N) and others where it is limited by phosphorus (P). Five long-term fertilization experiments have further broadened the range of nutrient availabilities experienced by Metrosideros. Adding P to P-limited sites increased foliar P concentrations threefold and litter P concentrations up to 10-fold; lignin concentrations decreased, and the decomposability of leaf litter increased from 32%–35% to 36%–46% mass loss in the first year. Adding N to N-limited sites increased leaf and litter N concentrations by only 15%–20%, with little or no effect on the decomposability of tissue.

Metrosideros polymorpha, a dominant tree species in Hawaiian ecosystems, occupies a wide range of habitats. Complementary field and common-garden studies of M. polymorpha populations were conducted across an altitudinal gradient at two different substrate ages to ascertain if the large phenotypic variation of this species is determined by genetic differences or by phenotypic modifications resulting from environmental conditions. Several characteristics, including ecophysiological behavior and anatomical features, were largely induced by the environment. However, other characteristics, particularly leaf morphology, appeared to be mainly determined by genetic background. Common garden plants exhibited higher average rates of net assimilation (5.8 μmol CO2 m−2 s−1) and higher average stomatal conductance (0.18 mol H2O m−2 s−1) than their field counterparts (3.0 μmol CO2 m−2 s−1, and 0.13 mol H2O m−2 s−1 respectively). Foliar δ13C of most common-garden plants was similar among sites of origin with an average value of −26.9‰. In contrast, mean values of foliar δ13C in field plants increased substantially from −29.5‰ at low elevation to −24.8‰ at high elevation. Leaf mass per unit area increased significantly as a function of elevation in both field and common garden plants; however, the range of values was much narrower in common garden plants (211–308 g m−2 for common garden versus 107–407 g m−2 for field plants). Nitrogen content measured on a leaf area basis in common garden plants ranged from 1.4 g m−2 to 2.4 g m−2 and from 0.8 g m−2 to 2.5 g m−2 in field plants. Photosynthetic nitrogen use efficiency (PNUE) decreased 50% with increasing elevation in field plants and only 20% in plants from young substrates in the common garden. This was a result of higher rates of net CO2 assimilation in the common garden plants. Leaf tissue and cell layer thickness, and degree of leaf pubescence increased significantly with elevation in field plants, whereas in common garden plants, variation with elevation of origin was much narrower, or was entirely absent. Morphological characteristics such as leaf size, petiole length, and internode length decreased with increasing elevation in the field and were retained when grown in the common garden, suggesting a potential genetic basis for these traits. The combination of environmentally induced variability in physiological and anatomical characteristics and genetically determined variation in morphological traits allows Hawaiian M. polymorpha to attain and dominate an extremely wide ecological distribution not observed in other tree species.

Hawaiian forests are subject to the effects of periodic hurricane conditions. Hurricane Iniki struck the island of Kauai, Hawaii on September 11, 1992 with winds exceeding 200 km/h and caused defoliation, felling of trees by snapping and uprooting, and standing tree mortality due excessive limb and leaf loss. The purpose of this study was to evaluate if measured wood mechanical characteristics could be correlated with stem failure of trees under windstorm conditions. A field survey indicated that post-hurricane stem condition (snapped, uprooted, or standing) differed among five common canopy species and was significantly correlated with stem apparent elastic modulus (relative flexibility). Species that tended to snap had significantly higher apparent elastic moduli than those that remained standing or were uprooted. Wood density and stem diameter were not significantly related to stem failure mode. Native trees had a higher percentage per species of standing individuals but also had increased uprooting. Nonnative tree species were more often snapped and fewer were standing after the hurricane. The higher incidence of stem failure for introduced canopy trees may increase the spread of alien understory species following wind disturbance events. These relationships provide a simple means to predict relative differences in stem failure due to high wind conditions and should be considered in planning reforestation efforts on the Hawaiian Islands.

Although trees comprise a primary component of terrestrial species richness, the drivers and temporal scale of divergence in trees remain poorly understood. We examined the landscape-dominant tree, Metrosideros polymorpha, for variation at nine microsatellite loci across 23 populations on young Hawai'i Island, sampling each of the island's five varieties throughout its full geographic range. For four varieties, principal coordinate analysis revealed strong clustering of populations by variety across the 10 430 km(2) island, indicating partitioning of the species into multiple evolutionarily significant units. The single island-endemic form, riparian var. newellii, showed especially strong differentiation from other varieties despite occurring in sympatry with other varieties and likely evolved from a bog form on the oldest volcano, Kohala, within the past 500 000 years. Along with comparable riparian forms on other Pacific Islands, var. newellii appears to represent parallel incipient ecological speciation within Metrosideros. Greater genetic distance among the more common varieties on the oldest volcano and an inverse relationship between allelic diversity and substrate age appear consistent with colonization of Hawai'i Island by older, partially diverged varieties followed by increased hybridization among varieties on younger volcanoes. This study demonstrates that broad population-level sampling is required to uncover patterns of diversification within a ubiquitous and long-lived tree species. Hawaiian Metrosideros appears to be a case of incipient radiation in trees and thus should be useful for studies of divergence and the evolution of reproductive isolating barriers at the early stages of speciation.

The genus Metrosideros includes several tree, shrub and vine species, native to the Pacific Islands. Seedlings from 25 seed lots of Metrosideros polymorpha and two seed lots of M. tremuloides with symptoms of root rot, stem girdling, wilting and round, purple leaf spots were observed in the Forestry Nursery at the Universidade Federal de Viçosa, Brazil. In the original disease site, seedling mortality reached up to 71% in M. polymorpha and 34% in M. tremuloides. Single conidial cultures obtained from infected leaf, root and stem samples of M. polymorpha were used to identify the fungal species. Morphological characters and DNA sequences of four loci, containing partial sequences of β-tubulin (TUB2), histone H3 (HIS3), calmodulin (CAL) and the elongation factor (tef-1α) genes of three isolates, indicated that they belong to a new species, described here as Calonectria metrosideri sp. nov. Potting medium infestation and inoculation of seedlings of M. polymorpha with an inoculum suspension at 1 × 104 conidia ml−1 induced typical symptoms of the disease (leaf spots, root rot and wilt), similar to those observed under natural conditions. Calonectria metrosideri was re-isolated, which fulfilled Koch's postulates, and confirmed its status as a pathogen.

The management and removal of invasive species may give rise to unanticipated changes in plant-pollinator mutualisms because they can alter the composition and functioning of plant-pollinator interactions in a variety of ways. To utilize a functional approach for invasive species management, we examined the restoration of plant-pollinator mutualisms following the large-scale removal of an invasive nectar thief and arthropod predator, Vespula pensylvanica. We reduced V. pensylvanica populations in large plots managed over multiple years to examine the response of plant-pollinator mutualisms and the fruit production of a functionally important endemic Hawaiian tree species, Metrosideros polymorpha. To integrate knowledge of the invader's behaviour and the plant's mating system, we determined the efficacy of V. pensylvanica as a pollinator of M. polymorpha and quantified the dependence of M. polymorpha on animal pollination (e.g. level of self-compatibility and pollen limitation). The reduction of V. pensylvanica in managed sites, when compared to unmanaged sites, resulted in a significant increase in the visitation rates of effective bee pollinators (e.g. introduced Apis mellifera and native Hylaeus spp.) and in the fruit production of M. polymorpha. Apis mellifera, following the management of V. pensylvanica, appears to be acting as a substitute pollinator for M. polymorpha, replacing extinct or threatened bird and bee species in our study system. Synthesis and applications. Fruit production of the native M. polymorpha was increased after management of the invasive pollinator predator V. pensylvanica; however, the main pollinators were no longer native but introduced. This research thus demonstrates the diverse impacts of introduced species on ecological function and the ambiguous role they play in restoration. We recommend incorporating ecological function and context into invasive species management as this approach may enable conservation managers to simultaneously minimize the negative and maximize the positive impacts (e.g. taxon substitution) of introduced species. Such novel restoration approaches are needed, especially in highly degraded ecosystems. Fruit production of the native M. polymorpha was increased after management of the invasive pollinator predator V. pensylvanica; however, the main pollinators were no longer native but introduced. This research thus demonstrates the diverse impacts of introduced species on ecological function and the ambiguous role they play in restoration. We recommend incorporating ecological function and context into invasive species management as this approach may enable conservation managers to simultaneously minimize the negative and maximize the positive impacts (e.g. taxon substitution) of introduced species. Such novel restoration approaches are needed, especially in highly degraded ecosystems. © 2012 British Ecological Society.

Throughout the 1960s and 1970s there was a rapid decline and canopy dieback in the Metrosideros polymorpha dominated rain forest of Hawai'i. An analysis of air photo sets from 1954, 1965, and 1972, covering the windward slopes of Mauna Kea and Mauna Loa, gave support for an alien disease hypothesis. A total demise of the native forest was predicted for the early 1990s. This prediction as well as the disease hypothesis proved to be wrong. Various searches for a single climatic cause also failed to explain the dieback. The spatial dynamics of the dieback phenomenon were newly analyzed with an additional air photo set from 1977 and by using GIS with spatial statistics. Two juxtaposed and climatically similar landscape matrix samples of ca. 200 km2, one each on Mauna Loa and Mauna Kea, were subjected to an analysis of landform heterogeneity and superimposed dieback patterns. The Mauna Loa matrix displays up to 15 000 yr old lava flows, while the Mauna Kea matrix displays up to 250 000 yr old substrates. Initiation of dieback occurred simultaneously on both mountains and was highly correlated with poorly-drained sites. The progression of dieback, however, followed a gradient of decreasing soil moisture, which often terminated at clearly recognizable substrate boundaries in the Mauna Loa matrix and moved over well-drained hill sites in the Mauna Kea matrix. Metrosideros dieback spread across the entire spectrum of volcanic substrates and habitat moisture regimes and developed from a smaller into a larger patch mosaic. By 1977, ca. 50 % of the forest area in both sample matrices had gone into dieback. Thereafter, the dieback came to a halt. The domino-type collapse, which frequently came to a halt at volcanic substrate boundaries, indicates that stands in better drained sites were also predisposed to die. Stands on adjoining substrates often survived. Substrates with dieback stands displayed no other obvious vigor-reducing stresses. The canopy trees on such substrates may have a common history, such as a major disturbance (including dieback) that synchronized stand development in the past. Subsequent weather disturbances and other abiotic/endogenous stresses associated with stand maturation, such as nutrient limitations and stand-level senescence, may reinforce a rhythmic synchrony over several generations of canopy cohorts.

Density, annual survival, philopatry, and movements of two species of Hawaiian honeycreepers, the Apapane (Himatione sanguinea) and the Iiwi (Vestiaria coccinea), were studied at four sites on the island of Hawaii. Highest densities of both species occurred during the breeding season and were highly correlated with flowering by Metrosideros. Annual survival probability (the complement of which includes permanent emigration) was 0.13 ± 0.07 for hatching-year (HY) Apapane, 0.72 ± 0.11 for adult Apapane, 0.09 ± 0.05 for HY Iiwi, and 0.55 ± 0.12 for adult Iiwi. Survival of adult Iiwi was the lowest of six species of native Hawaiian forest birds and may be related to their high susceptibility to avian disease. Small resident populations of both species remained on our study sites throughout the year, but 78% of 1,361 Apapane and 82% of 891 Iiwi were never captured or seen after their initial capture. Widespread movements of Apapane and Iiwi in response to the seasonal and patchy availability of Metrosideros nectar have important implications for disease transmission since Apapane are the primary carrier of avian malaria and avian pox in Hawaii, and Iiwi appear to be highly susceptible to mortality from malaria.

We determined the consequences of systematic changes in nutrient availability during long-term soil development by measuring foliar nutrient concentrations. Sun leaves of the dominant tree Metrosideros polymorpha and of eight other species were sampled in Hawaiian rain forests developed on substrates that were 0.3 x 10 3 , 2.1 x 10 3 , 5 x 10 3 , 20 x 10 3 , 150 x 10 3 , 1400 x 10 3 , and 4100 x 10 3 yr old. Elevation, annual precipitation, parent material, and dominant species were nearly constant along this gradient. Foliar N and P concentrations in Metrosideros were lowest in the youngest site (0.72% and 0.052% for N and P, respectively), increased to a maximum on 20 X 10 3 and 150 x 10 3 -yr-old substrates (1.45% and 0.108%), and then declined close to the initial concentrations in the oldest site (0.86% and 0.061%); N:P ratios in foliage varied relatively little across the sites. Most other species followed a similar pattern of variation. On a per unit leaf area basis, foliar N and P contents in Metrosideros also peaked on intermediate-aged substrates. Foliar nutrient concentrations in Metrosideros sun leaves were determined across a parallel but wetter substrate age gradient. The pattern of variation was similar on both gradients, but the magnitude of variation was smaller on the wetter sequence of sites. Overall, the pattern of variation in foliar nutrients with substrate age is consistent with conceptual models for the dynamics of soil nutrient availability during long-term soil development, and with measurements of soil properties along this sequence.

Plant roots are an important component of underground food webs in mesocaverns, lava tubes, and solution caves. Trees such as Metrosideros , Eucalyptus , Ficus , and Brachychiton are adapted to send their roots through porous rock to get water and nutrients. These trees are primary producers, photosynthesizing and sending energy in the form of carbohydrates into their roots. Surface species that live on and around roots may venture deep underground along roots, but most are not able to survive deep in caves and become food for predators and scavengers. In some groups, including the planthopper family Cixiidae and the moth family Noctuidae, new species have evolved traits that allow them to spend their entire life cycle underground. Besides these primary consumers (herbivores), tree root communities in caves include carnivores, detritivores, decomposers, and fungivores. Many of these animals are obligate cave species (troglobites) and are generally restricted to habitats with high humidity and low air motion found in mesocaverns and the deep cave zone. Protection of troglobites in tree root communities requires more than simply protecting the caves in which they occur, it requires determining the plant species that provide the roots, and protecting these species on the surface over the cave and associated mesocaverns.

We determined controls on litter decomposition and nutrient release for the widespread native tree Metrosideros polymorpha in 11 sites arrayed on gradients of elevation, precipitation, and substrate age on Hawaiian lava flows. The effects of site characteristics were evaluated using three common substrates (Metrosideros leaf litter from one of the sites, wood dowels, and filter paper) decomposed in each of the sites, and the inherent decomposability of tissue (substrate quality) was evaluated using Metrosideros leaf litter from each of the sites decomposed in a common site. Site characteristics were responsible for most of the variation in rates of decomposition in the range of sites and substrates examined. Common substrates decomposed much more rapidly in warm, low elevation sites; apparent Q10 values, calculated on the basis of variation in mean annual temperature with elevation on individual lava flows, ranged from 4 to 11. Litter decomposed slowly in the dry sites, but leaf litter produced in the dry sites decomposed more than twice as rapidly as litter from wet sites when both were measured in the same site. The higher substrate quality of litter from dry sites could be due to trade—offs among nutrient—use efficiency, water—use efficiency, and carbon gain by water—limited Metrosideros. We used these results to test a revision of the CENTURY soil organic matter model that had been designed to simulate the decomposition of surface litter. Simulations accurately matched the pattern but underestimated the magnitude of among—site differences in the decomposition of common substrates in a range of sites. Analyses of both field and simulation results suggested that the decomposition of Metrosideros leaf litter could be limited by nitrogen availability.

Mesosepis papua Wygodzinsky Figs. 19, 20 Mesosepis papua Wygodzinsky, 1966: 396 ���398, fig. 119. Material examined. AUSTRALIA: Queensland: 1 ��, Cape York, Top Rocky Yard, 13.9 o S 143.2 o E, 3 May 1961, J.L. Gressitt (BPBM); 1 sex unknown, Crystal Cascades, 16.6 o S 145.3 o E, May 1994 (QM); 1 sex unknown, 3 km E. Lockerbie, Cape York, 10.8 o S 142.5 o E, 19���22 March 1987, G.B. Monteith, Pyrethrum on logs, RF (QM); 2 sex unknown, Kuranda, 16.8 o S 145.6 o E, 22���28 December 1958, D.K. McAlpine (AM). Diagnosis. This species can be recognized in Australia by the diagnostic features of the genus as well as its wing patterning (Fig. 19). Distribution. Northern Queensland and New Guinea (Fig. 20). Remarks. Wygodzinsky (1966) described this species as occurring only in New Guinea, though he remarks that a second species is known, but not described, from Australia. Our observations suggest that all Australian material from this genus appears to be conspecific with M. papua., Published as part of Tatarnic, Nikolai J., Wall, Michael A. & Cassis, Gerasimos, 2011, A systematic revision of the Australian ploiarioline thread-legged assassin bugs (Hemiptera: Reduviidae: Emesinae), pp. 1-30 in Zootaxa 2762 on pages 27-28, DOI: 10.5281/zenodo.203726, {"references":["Wygodzinsky, P. (1966) A monograph of the Emesinae (Reduviidae, Hemiptera). Bulletin of the American Museum of Natural History, 133, 1 - 614."]}

We tested the hypothesis that trees growing at high elevations with occasional freezing temperatures have smaller diameter xylem vessels than trees of the same species growing at lower and warmer elevations. The young branch wood of the wide-ranging Hawaiian tree species Metrosideros polymorpha (Myrtaceae) was examined in three natural field populations (high, middle, and low elevations: 2469, 1280, and 107 m a.s.l., respectively) and contrasted with seedlings from these populations that were grown in a common garden at middle elevation (1190 m). Previous studies showed that these populations have some genetic differences and have distinctive leaf structure and ecophysiological traits. Vessel diameter was significantly smaller in the high elevation field and common garden plants than in middle elevation plants. However, high elevation vessels were wider in common garden plants compared to field plants, indicating that vessel diameter is determined both by genotype (parental populations) and environment (growing conditions different from those of parents). Reduced vessel diameter has implications for resistance to cavitation induced by freezing and/or drought in plants growing near tree line in Hawaii.

Calonectria spp. are important pathogens of ornamental plants in nurseries, especially in the Northern Hemisphere. They are commonly associated with a wide range of disease symptoms of roots, leaves and shoots. During a recent survey in Tunisia, a number of Calonectria spp. were isolated from tissues of ornamental plants showing symptoms of leaf spot, crown and root rot. The aim of this study was to identify these Calonectria spp. using morphological and DNA sequence comparisons. Two previously undescribed Calonectria spp., C. pseudomexicana sp. nov. and C. tunisiana sp. nov., were recognised. Calonectria mexicana and C. polizzii are newly reported for the African continent. Pathogenicity tests with all four Calonectria spp. showed that they are able to cause disease on seedlings of Callistemon spp., Dodonaea viscosa, Metrosideros spp. and Myrtus communis.

An overview of forest diebacks in regions of the Pacific Rim strongly implicated extreme climatic fluctuations as a cause of dieback in the absence of significant acidic deposition and O3 pollution. There was strong circumstantial evidence that extreme moisture fluctuations had incited cavitation injury on Eucalyptus, Metrosideros and Nothofagus species with recent dieback.

Three taxa of Myrtaceae leaf macrofossils, including Eucalyptus sp. and Metrosideros sp., are described from Miocene Manuherikia Group sediments of Central Otago, New Zealand. A number of undetermined myrtacean leaves are also illustrated. Two types of Myrtaceae fruiting bodies are described. One of these is identified as Eucalyptus sp.

A late Pleistocene palynological record of vegetation and climate is investigated from a 5m lignite section within terrestrial cover beds of the Ngarino Marine Terrace on Ararata Road, near Hawera, south Taranaki, New Zealand. The pollen assemblages are dominated throughout by high levels of pollen derived from gymnosperm trees. A lower zone (AR1) is characterised by high levels of pollen of Prumnopitys taxifolia, Libocedrus, shrubs and grass, interpreted to represent a stadial phase with climate cooler and drier compared with present. A middle zone (AR2) is characterised by high levels of pollen of P. taxifolia, Dacrydium cupressinum, Metrosideros and spores of Cyathea dealbata-type and of the bryophyte Bryosporis anisopolaris Mildenhall and Bussell. Pollen values for Libocedrus and grass are low. These assemblages are similar to Holocene pollen spectra in the region but differ in containing high levels of Dracophyllum-type and Restionaceae pollen, and Gleichenia spores. The zone also lacks any significa...

Genetic evidence for recent and incipient speciation in the evolution of Hawaiian Metrosideros (Myrtaceae)

Myricafjaya, an introduced nitrogen-fixing tree, is rapidly invading volcan- ically disturbed forests in Hawaii Volcanoes National Park on the island of Hawai'i. We investigated the direct effects of Myrica on the establishment and growth of the native tree, Metrosideros polymorpha, in a forest that is recovering from burial under a 10-200 cm deep layer of volcanic cinder. The number of Metrosideros seedlings found under Metro- sideros trees, in the open, and under Myrica trees was 0.12/M2, 0.01/m2, and zero, re- spectively. Myrica litter inhibited Metrosideros germination in field experiments; germi- nation occurred only when Myrica litter was removed. In open sites, the addition of nitrogen-rich Myrica soils increased dry mass accumulation of transplanted Metrosideros seedlings. Shade from Myrica canopies (or shade cloth) in- creased survivorship and height growth but not dry mass accumulation of Metrosideros seedlings. Isolated Metrosideros trees increased diameter growth in response to nitrogen fertilizer but not in response to the presence of adjacent Myrica trees, despite previous findings that Myrica trees elevate available nitrogen in the soil. Myrica basal diameter and height growth were consistently greater than that of Metrosideros in all size classes. Although Myrica does not readily invade closed, late-successional Metrosideros forests, on young, volcanically disturbed soils it is rapidly establishing dense, monospecific stands under which Metrosi- deros does not regenerate.

A one year pollen trapping study across the Southern Alps, New Zealand, is described. A specially-designed trap collected pollen from seven forested and non-forested sites during all four seasons of the year from October 1987 to September 1988. The accumulation rates of the pollen of broadleaved angiosperm trees (Metrosideros umbellata, Quintinia acutifolia and Weinmannia racemosa) were most concentrated near their source, but declined rapidly a few hundred metres away. Metrosideros pollen had the highest accumulation rate of all the taxa studied. More Nothofagus fusca type pollen was collected from the grassland sites than in the forested areas. The pollens of herbaceous species were scarce in forested areas. Pollens of local taxa were most frequent, especially in redeposited material. Redeposition contributed a relatively small part of the annual pollen deposition.

Knowledge of the evolutionary history of plants that are ecologically dominant in modern ecosystems is critical to understanding the historical development of those ecosystems. Metrosideros is a plant genus found in many ecological and altitudinal zones throughout the Pacific. In the Hawaiian Islands, Metrosideros polymorpha is an ecologically dominant species and is also highly polymorphic in both growth form and ecology. Using 10 non-coding chloroplast regions, we investigated haplotype diversity in the five currently recognized Hawaiian Metrosideros species and an established out-group, Metrosideros collina , from French Polynesia. Multiple haplotype groups were found, but these did not match morphological delimitations. Alternative morphologies sharing the same haplotype, as well as similar morphologies occurring within several distinct island clades, could be the result of developmental plasticity, parallel evolution or chloroplast capture. The geographical structure of the data is consistent with a pattern of age progressive island colonizations and suggests de novo intra-island diversification. If single colonization events resulted in a similar array of morphologies on each island, this would represent parallel radiations within a single, highly polymorphic species. However, we were unable to resolve whether the pattern is instead explained by ancient introgression and incomplete lineage sorting resulting in repeated chloroplast capture. Using several calibration methods, we estimate the colonization of the Hawaiian Islands to be potentially as old as 3.9 (−6.3) Myr with an ancestral position for Kaua'i in the colonization and evolution of Metrosideros in the Hawaiian Islands. This would represent a more ancient arrival of Metrosideros to this region than previous studies have suggested.

We used airborne imaging spectroscopy and scanning light detection and ranging (LiDAR), along with bioacoustic recordings, to determine how a plant species invasion affects avian abundance and community composition across a range of Hawaiian submontane ecosystems. Total avian abundance and the ratio of native to exotic avifauna were highest in habitats with the highest canopy cover and height. Comparing biophysically equivalent sites, stands dominated by native Metrosideros polymorpha trees hosted larger native avian communities than did mixed stands of Metrosideros and the invasive tree Morella faya. A multi-trophic analysis strongly suggests that native avifauna provide biotic resistance against the invasion of Morella trees and exotic birds, thus slowing invasion “meltdowns” that disrupt the functioning of native Hawaiian ecosystems.

The pollen and spores dispersing from natural and semi-natural vegetation in the South Island of New Zealand were studied from moss polsters collected from 35 sites along a transect from Westland across the Southern Alps to Canterbury. Sites in Westland were dominated by local broadleaved angiosperm species (Metrosideros, Quintinia, Weinmannia) and Poaceae pollen. Sites above the treeline on the Main Divide showed anomalous high counts of exogenous Podocarpaceae pollen. This seems to be washed out of strong NW winds by orographic precipitation. Peat cores taken from 3 sites confirm that exogenous podocarp pollen influx has continued over at least the last 500 years. Nothofagus pollen dominates within the beech forest areas, but drops to 10% a short distance from the forest edge. Poaceae pollen shows low frequencies in forested sites, but dominates in grassland areas.

Soil nutrient stresses have been determined to contribute to stand-level dieback in two Pacific forest biomes, the Hawaiian Metrosideros rain forest and remnants of the eastern Australian Eucalyptus forest. In the Hawaiian dieback, low levels of N limit indigenous forest development early in primary succession on volcanic soils, while later in primary succession, stresses appear to be associated with soil aging, acidification, loss of cations, decreasing levels of P, increases in soluble Al, and, under poor drainage, sharp increases in soluble Fe. These nutrient limitations put a ceiling on stand development and growth and are considered as one of the three causes predisposing stands to dieback. In the rural or New England dieback of eastern Australia, indigenous eucalypts are adapted to ancient soils with very low levels of P, but pasture improvement with clover and fertilization with superphosphate has imposed different stresses on remnant eucalypts in pastures and nearby forest islands. After fertilization, the trees grow faster initially, but their foliage becomes highly nutritious for insects. Other factors also contribute to a build-up of insects as pests, which now threaten the remaining eucalypts. The rural dieback represents an example of how forests with low canopy species diversity, simplified structure, lack of successional species, and which are prone to dieback under natural conditions, can be destroyed by intensification of agricultural development. The paper closes with a summary of generic factors that were found to cause forest dieback under natural conditions and compares these to the anthropogenically superimposed stresses that led to aggravated tree and forest decline in the Australian rural or New England dieback. The suggestion is made that comparative dieback research at the global level will lead to an improved understanding of natural forest dynamics as an aid in interpreting the new stresses. imposed on forests by human activity.

The ratios of carbohydrate sink to source in the shoot systems of mature and juvenile Metrosideros polymorpha trees were compared, testing a prediction of the pipe model theory that this ratio is proportional to height, thus explaining the synchrony of forest decline in even-height stands. Volumes of sapwood (S) and inner bark (IB), and leaf mass (L) were measured by destructive sampling in 5 mature and 12 juvenile trees. S:L and IB:L of mature tree shoot systems were higher than of juvenile trees, strongly supporting the hypothesis that mature trees have a lower surplus of carbohydrate production and are less resistant to many forms of stress. The specific leaf burden (S:L and IB:L jointly) within the mature tree sample varied by a factor of about 2, compared with a variation in height by a factor of about 1.3 5, suggesting that a relatively strong environmental stress is needed to trigger the synchronous death of all or most trees in a stand. The pipe model, with its prediction of constant Huber value (stem cross-sectional area per unit supported leaf mass), does not accurately represent the distribution of either the sapwood or the inner bark in M. polymorpha. The sapwood Huber values varied significantly among the organ systems of individual trees and between life states. Within each organ system the sapwood cross-sectional area in larger stems was strongly correlated with supported leaf mass, while the inner-bark cross-sectional area was better correlated with the cross-sectional area of the stem. Sapwood Huber values were similar in twigs and small branches of juvenile and mature trees, but were much lower in the larger stems of mature trees than at any point in the juvenile trees. The pattern of variation of the inner-bark Huber values among organ systems was similar in juvenile and mature trees. A reduction of the sapwood Huber value in the large stems of mature trees associated with heartwood development decreased the rate of increase of S:L with size. IB: L increased very little in the juvenile state, but it increased rapidly in the mature state when leaf mass failed to increase in linear proportion with total tree volume. The volume of inner bark was found to be about one-half as great as the volume of sapwood in mature trees, but is likely to be responsible for a disproportionate part of total aboveground respiration.

Myrtus angustifolia Linnaeus, Systema Naturae, ed. 12, 2: 340; Mantissa Plantarum: 74. 1767. "Habitat ad Cap. b. spei." RCN: 3606. Type not designated. Original material: Schreber, Herb. Linn. No. 637.7 (LINN); [icon] in Burman, Rar. Afric. Pl.: 237, t. 83, f. 2. 1739. Current name: Metrosideros angustifolia (L.) Sm. (Myrtaceae)., Published as part of Jarvis, Charlie, 2007, Chapter 7: Linnaean Plant Names and their Types (part M), pp. 651-689 in Order out of Chaos. Linnaean Plant Types and their Types, London :Linnaean Society of London in association with the Natural History Museum on page 687, DOI: 10.5281/zenodo.291971