Discaria Toumatou Research Articles

Do Woody Plants Facilitate Herbaceous Plants in Dryland New Zealand?

Aims: Woody plants are postulated to facilitate understory herbaceous plants in arid and semi-arid environments worldwide, the so-called ‘nurse plant’ effect, but this mechanism. has been little studied in the drylands of New Zealand. Indigenous dryland plants postulated to have grown under woody shrubs in New Zealand before European settlement may benefit from their recovery, or even their replacement by exotic substitutes. The aim of this study was to investigate woody pant facilitation of understory herbaceous plants in dryland New Zealand.
 Study Design: In this study I investigated the effects of canopies of four shrub species – Kunzea serotina, Discaria toumatou, Rosa rubiginosa and Coprosma propinqua – on herbaceous plant species richness, in the presence and absence of rabbit grazing (for K. serotina).
 Place and Duration of Study: The study was conducted in the drylands of Central Otago, New Zealand, from August 2007 to January 2009.
 Results: Herbaceous plant species richness was lower under canopies of K. serotina, possibly because the dense canopy shaded the understorey plants. It was higher under C. propinqua, D. toumatou and R. rubiginosa canopies than in their adjacent open grasslands, but for all three species this effect was seen only in winter. Woody plant canopy protection of understorey herbaceous plants against winter frost may explain the effects. Grazing significantly decreased herbaceous plant species richness. Since D. toumatou, R. rubiginosa and C. propinqua showed facilitative effects on herbaceous plant species richness they are possible agents for the restoration of dryland vegetation.
 Conclusion: I conclude that control of grazing and the protection of these three woody species could be a good management strategy for the maintenance of a predominantly indigenous dryland mixed herbaceous and woody vegetation in Central Otago.

Do woody plants create ‘fertile islands’ in dryland New Zealand?

Woody plants in arid and semi-arid environments may enhance soil nutrient status, the so-called ‘fertile island’ effect, but this mechanism has never been tested in the drylands of New Zealand. In this study I investigated effects of Kunzea serotina, Discaria toumatou, Rosa rubiginosa, and Coprosma propinqua on soil properties in the drylands of central Otago, New Zealand. Soils had significantly higher organic matter under C. propinqua and significantly higher nitrate and phosphorus concentrations under K.

Persistence of biodiversity in a dryland remnant within an intensified dairy farm landscape

The lowland Canterbury Plains of New Zealand have been extensively modified since human occupation, but with recent conversions to irrigated dairy farming very few remnants of native dryland vegetation remain in the region. We investigated soil chemistry, plant distribution and soil invertebrates along transects in Bankside Scientific Reserve, a small (2.6 ha) remnant. The vegetation is a mosaic of native woody shrubs, predominantly Kunzea serotina (kanuka, Myrtaceae) and Discaria toumatou (matagouri, Rhamnaceae), and dry grassland. Changed soil conditions appear to have made the reserve less conducive for native species, but better suited to invasion by exotic plants. Compared with detailed surveys before the dairy conversion, only 31% of the original 65 native vascular plant species were recorded in the present study and 27 new exotic species had arrived since the original survey. Soil nutrient concentrations and pH were lower in the reserve than in surrounding farmland; peaks of nitrate and ammonium were recorded at the boundary. Soil phosphate was elevated in lower-lying areas within the reserve, an effect associated with natural drainage channels and evident up to 20 m into the reserve. Four species of native megascolecid earthworms were found in the reserve but not in neighbouring pasture, whereas the diversity and abundance of beetles and spiders in the reserve was similar to that observed at least 10 m into surrounding farmland. This study highlights the importance of the soil environment in sustaining biodiversity. We conclude that this remnant retains valuable communities of native species, but is apparently being impacted by phosphate encroachment and habitat fragmentation. This does not appear to be an intractable management issue for the interface between agricultural systems and conservation sites within a dairy landscape mosaic. We suggest that attention is required to maintain buffer zones adjacent to small, isolated and vulnerable remnants of original biota that are surrounded by intensive agriculture.

Multiple factors determine the rate of increase of an invading non-native tree in New Zealand

We reconstructed the invasion of a non-native tree (hawthorn, Crataegus monogyna) into fire-induced grassland in montane South Island, New Zealand. Using the relationship between height and age to reconstruct the rate of increase of the population, we identified three distinct invasion phases. We hypothesised that these related to the abundance of woody vegetation and therefore of non-native blackbirds (Turdus merula), the primary disperser of hawthorn in this environment. From the 1930s to 1959, increase was relatively slow, with hawthorn spread probably constrained due to browsing of seedlings by European rabbits (Oryctolagus cuniculus) and the low abundance of a native N-fixing shrub (matagouri, Discaria toumatou) providing few perches and nesting sites for blackbirds and safe sites for hawthorn establishment. Subsequently, from 1959 to 1976, hawthorn showed greater than six fold acceleration in its rate of population increase, resulting largely from intensive rabbit control, less frequent fires, and aerial topdressing of phosphate fertilizer promoting the growth of matagouri scrub. In addition, maturing hawthorn trees provided additional food and nesting sites for blackbirds. Hawthorn population increase slowed again from 1976, possibly because most suitable habitat in the immediate vicinity of the population neared saturation. From this case study we have constructed a general hypothesis for the factors determining the rate of invasion of matagouri—grassland habitats by bird-dispersed non-native woody plants in montane New Zealand.

Distribution of native forest in the upper Clutha district, Otago, New Zealand

The upper Clutha district extends from steep, glaciated mountains along the South Island Main Divide to broad plateaus and terraced valleys further downstream, and covers an annual precipitation gradient from 4000 m to 400 mm. all forest prevails from the valley floors to the subalpine tree limit in n0fi‐weste‐n headwaters, but southwards down the rainfall gradient becomes increasingly confined to small pockets. Nothofagus is overwhelmingly dominant, with N. menziesii prevailing in the north‐west and N. solandri vu. cliffortioides in drier country to the east. Pockets of forest in the south of the district cm consist of ei&er species. Nothofagus fusca co‐do&ates with the other Nothofagus species at low altitudes through part of the Matukituki catchment, and Over a small area by Lake Hawea. Low‐altitude N. menziesii forest in the Makarora Valley has a similar composition to forests west of the Main Divide, and includes several conifer species and a wide range of broad‐leaved trees, notably Weinrnannia racemosa. The hardiest conifers, Podocarpus hallii and Phyllocladus alpinus, are widely distributed in the Nothofagus forests of the district and also dominate small stands of native trees on otherwise treeless mountains. In the moister part of the district Kunzea ericoides and Leptospemum scoparium are succes‐sional to broad‐leaved forest, whereas in the drier parts they are self‐perpetuating. Grey scrub, dominated mainly by Discaria toumatou, is widespread on slopes where rainfall is low, and on river flats under higher rainfall. Small trees of Sophora microphylls and Olearia spp. occw locally in this scrub.

Shrub succession and invasibility in a New Zealand montane grassland

Abstract Two successive shrub invasions of a short tussock grassland induced by grazing and burning were examined in montane South Island, New Zealand. The first invasion was by a native shrub, matagouri (Discaria toumatou Raoul). The second invasion was by an exotic shrub, Scotch broom (Cytisus scoparius (L.) Link), which invaded the matagouri shrubland that had developed over the grassland. The invasions were investigated using analysis of spatial patterns of both shrubs and tussocks, and age, growth rates and size structure of the shrubs. Competition between the two shrub species was examined using spatial patterns and comparing allometric relationships. After initial invasion by matagouri of the grasslands, stand density increased by consolidation about its initial colonization points. Current matagouri distribution is often negatively associated with tussocks. Scotch broom occurs most frequently in a dense sward of introduced grasses and occasionally in tussocks in interstices among matagouri shrubs. Despite the palatability of Scotch broom to sheep that graze the site, there was no evidence that the spiny matagouri facilitates invasion by protecting Scotch broom seedlings; rather there was negative association between the shrub species. The two species probably compete for above‐ground space. However, diameter and height growth rates of Scotch broom far exceed those of matagouri so Scotch broom is likely to increase in biomass rapidly at the site. The autogenic organization and disturbance history of the resident plant communities have rendered each vulnerable to successive invasions.

A macrofossil flora from early Aranuian lake-bed deposits, Doubtful River, Waiau-uha catchment, North Canterbury, New Zealand

Sediments deposited in an early Aranuian lake in a mountain valley contain abundant, well-preserved fossil wood, leaves, and seeds. Radiocarbon dates ranging from 13 300 to 10 800 yr B.P. have been obtained for wood samples. The macrofossil species represented all grow in the region today. By analogy with modern plant communities, the fossil assemblage appears to be drawn from two main kinds of vegetation complex: hillside scrub, with Phyllocladus alpinus a major component; and valley-floor communities, including river floodplain, with Racomitrium lanuginosum abundant and associated grassland with dwarf shrubs (Leucopogon fraseri) and thorn scrub (Discaria toumatou). The scarcity of Podocarpus hallii fossils suggests that the climate was cooler than now. Archeria traversii fossils indicate that precipitation was at least as high as now.

Amplification of 16S rRNA genes from Frankia strains in root nodules of Ceanothus griseus, Coriaria arborea, Coriaria plumosa, Discaria toumatou, and Purshia tridentata.

To study the global diversity of plant-symbiotic nitrogen-fixing Frankia strains, a rapid method was used to isolate DNA from these actinomycetes in root nodules. The procedure used involved dissecting the symbiont from nodule lobes; ascorbic acid was used to maintain plant phenolic compounds in the reduced state. Genes for the small-subunit rRNA (16S ribosomal DNA) were amplified by the PCR, and the amplicons were cycle sequenced. Less than 1 mg (fresh weight) of nodule tissue and fewer than 10 vesicle clusters could serve as the starting material for template preparation. Partial sequences were obtained from symbionts residing in nodules from Ceanothus griseus, Coriaria arborea, Coriaria plumosa, Discaria toumatou, and Purshia tridentata. The sequences obtained from Ceonothus griseus and P. tridentata nodules were identical to the sequence previously reported for the endophyte of Dryas drummondii. The sequences from Frankia strains in Coriaria arborea and Coriaria plumosa nodules were identical to one another and indicate a separate lineage for these strains. The Frankia strains in Discaria toumatou nodules yielded a unique sequence that places them in a lineage close to bacteria that infect members of the Elaeagnaceae.

A method for inducing rapid germination in seed ofDiscaria toumatouRaoul

A reliable technique for achieving rapid seed germination in matagouri or wild Irishman (Discaria toumatou Raoul), an endemic woody shrub with seed which had previously proved difficult to germinat...

Late Holocene displacements and characteristic earthquakes on the Hope River segment of the Hope Fault, New Zealand

Abstract On the Hope River segment of the Hope Fault, west of Hanmer Springs, New Zealand, a 36 m dextral offset of a dated river terrace riser indicates an average local late Holocene horizontal slip-rate of 10.5 ± 0.5 m/kyr. A trench excavated across the fault in a nearby swamp revealed five silt layers within a 1.5 m thick column of peat. Radiocarbon dates and plant pollen indicate that the base of the swamp is approximately 700 years old, so peat has accumulated at an average rate of 2.35 ± 0.6 mm/yr. The youngest silt layer was probably derived from a landslide triggered during an M 7–7.3 earthquake in 1888 ad, and the older silt layers are attributed to similar prehistoric (pre-1850 ad) earthquakes. Pollen from the lowest silt shows brief local dominance of lacebark (Hoheria cf. H. lyalli) during a phase of former beech (Nothofagus) forest. Sharp increases in the percentage of matagouri (Discaria toumatou) pollen follow the younger silt layers, which were deposited during a later period of fire-indu...

Vegetation/environment relationships in lowland and montane vegetation of the Kawarau Gorge, Central Otago, New Zealand

Abstract Vegetation patterns In the valley of the Kawarau Gorge, Central Otago, were examined using ordination and classification. Two-way Indicator Species Analysis revealed fifteen communities, many of which were dominated by the shrubs Rosa rubiginosa and Discaria toumatou, but which mostly differed in understorey species. Other distinct communities included scabweed, thyme/ brier, pasture, bracken, dense shrubland, and subalpine snow tussock grassland. Classification divisions were correlated to the 21 environmental factors measured at each site by using rank correlation coefficients. Various factors distinguished some of the fifteen communities, while higher level classification divisions were correlated with a number of factors Including position within the valley, altitude, aspect, grazing by rabbits, gravel, soil acidity, soil carbon, and the nutrients potassium and magnesium. Detrended Correspondence Analysis revealed a very clear xeric/mesic vegetation gradient In the first axis, and a poorly de...

Seasonal Pollen Collection by Honeybees from Grass/Shrub Highlands in Canterbury, New Zealand

SummaryHoneybee (Apis mellifera ligustica Spinola) pollen pellets were trapped weekly from September to May in a high country area inland from Christchurch, New Zealand. The major pollen types identified were Discaria toumatou, Taraxacum-type, Trifolium repens and Coprosma sp. Unmodified high country appears to have adequate spring pollen sources but there may be a dearth of forage sources in the late summer and autumn if Taraxacum-type s and thistles are not present. Indigenous anemophilous sources supplied over 80% of the pollen during the first two months in spring but very little through the rest of the year. Introduced entomophilous species were virtually the sole source over the last five months. Honeybees collected no pollen on six of the 38 observation dates due to adverse weather.

The Nutrient Composition of Honeybee-Collected Pollen in Otago, New Zealand

SummaryThe following pollen species were analysed for moisture, fat, carbohydrate, minerals and amino acids; white clover (Trifolium repens L,), willow (Salix sp. L,), hawkweed (Hieracium pilosela L.), broom (Cytisus sp. L,), bush lawyer/blackberry (Rubus sp. L.), matagouri (Discaria toumatou Raoul), pine (Pinus sp. L.), thistle (Cirsium sp. Miller) and kiwifruit (Actinidia deliciosa A. Chev.). The moisture content of the pollen ranged from 16·8% (matagouri) to 25·9% (willow). The fat content ranged from 0·17% (staminate kiwifruit pollen) to 13·40% (hawkweed). Total carbohydrate ranged from 12·6% (matagouri) to 29·6% (pistillate kiwifruit), while reducing sugars ranged from 11·1% (matagouri) to 25·7% (pistillate kiwifruit). The protein content, which is commonly regarded as an index of nutritional quality ranged from 2·9% (pistillate kiwifruit) to 23·5% (broom). Most of the species analysed contained sufficient nutrients for honeybee growth and development.

Protandry, pollination, and self-incompatibility inDiscaria toumatou

Abstract Discaria toumatou (Rhamnaceae) is a spiny shrub endemic to New Zealand. The small white flowers are protandrous. Pollen is presented first and removed by wasps, flies, and bees which visit the flowers; after one to three days the three stylar branches unfold and an exudate is produced covering the stigmatic area at the tip of each branch. Pollen germinates only on the three restricted receptive areas. Controlled crosses on field plants and fluorescent microscopy confirm that D. toumatou is self-incompatible. The site of inhibition is at the stigma. The species provides a clear example of the co-occurrence of dichogamy and self-incompatibility, and has an unspecialised pollination system as is characteristic of many New Zealand plants.

Control of matagouri with picloram in mixture with 2, 4, 5-T or triclopyr

Control of matagouri with picloram in mixture with 2, 4, 5-T or triclopyr

Flowering currant (Ribes sanguineum) shrublands in the lower Waitaki Valley, South Canterbury

Abstract Flowering currant (Ribes sanguineum) is classified as a noxious plant in Waitaki County, South Canterbury. On the north bank of the Waitaki River it forms scrub-grasslands w1th the spiny shrub, matagouri (Discaria toumatou), and species of Coprosma, particularly on shady hill slopes and gullies. The stem diameters of flowering currant and matagouri were measured and the ages were determined from ring counts. There is a close positive relationship between stem diameter and age in the flowering currant. Most seedlings establish beneath matagouri bushes and although flowering currant can spread by suckering and layering, this is largely prevented by sheep and rabbit grazing. Most flowering currant bushes are more than 10 years old, and the apparent spread of this plant in recent years has resulted from the suppression of matagouri growth by flowering currant bushes. The flowering currant stands are self-perpetuating, but they are being slowly invaded by wind-dispersed adventive trees. Flowering curr...

Alkaloid Occurrence in Discaria toumatou

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAlkaloid Occurrence in Discaria toumatouSirichai Panichanun, I. Ralph C. Bick, and John W. BluntCite this: J. Nat. Prod. 1982, 45, 6, 777–778Publication Date (Print):November 1, 1982Publication History Published online1 July 2004Published inissue 1 November 1982https://doi.org/10.1021/np50024a027RIGHTS & PERMISSIONSArticle Views92Altmetric-Citations2LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (146 KB) Get e-Alerts Get e-Alerts

Scrubweed cover of South Island agricultural and pastoral land

Abstract This paper reports a quantitative field survey of occurrence (percent ground cover) and distribution of 13 scrubweeds in South Island agricultural and pastoral land below 1 220 m above sea level. Most ground cover was recorded for bracken (Pteridium aquilinum var. esculentum 2.85%) followed by matagouri (Discaria toumatou, 2.66%) and gorse (Ulex europaeus 1.84%). Lower estimates were recorded for kanukalmanuka (Leptospermum spp., 1.23%), broom (Cytisus scoparius, 0.92%), and sweet brier (Rosa rubiginosa, 0.88%). Provincial occurrences and areas of farmable land covered by scrubweeds are reported.

Variation in the Phenology of Natural Populations of Montane Shrubs in New Zealand

SUMMARY (1) Variation in flowering time of individuals in one population of each of three species of shrub was recorded over two growing seasons in montane scrub-grassland in the South Island of New Zealand. (2) There was considerable variation in flowering time within each popuLlation, but the flowering rank-order of individuals in different years was positively correlated. (3) Variation in flowering time was poorly correlated witlh the dLuration of flowering and the number of flowers and fruits per plant, except that variation in flowering time in Discaria toumatou (Rhamnaceae) was weakly positively correlated with the percentage fruit set in 1976-77. If both earlier and later flowering plants showed reduced fruit set this would suggest stabilizing selection, but there is no indication of such a pattern. Weak and inconsistent directional phenotypic selection for flowering time can be demonstrated for these two species however. (4) In the warm, dry summer of 1977-78, Leptospermum scoparium (Myrtaceae) and Dracophyllumn spp. (Epacridaceae) flowered on average 9 days and 5 days earlier respectively and for 17 and 8 days shorter duration than in the cool, damp summer of 1976-77. Further, L. scoparium plants had a lower production of flowers and fruits in the second season in comparison with the first season. Plants of Discaria toumatou also flowered earlier in 1977-78, but the duration of flowering and flower and fruit production was greater in 1977-78 than in the 1976-77 season. (5) Patterns of variation in flowering time are also apparent among adjacent populations depending on altitude and on the major geographical units of the range of species. Variation in flowering time both at the individual and the population level may be an important adaptation by which selection and physiological mechanisms increase reproductive success.

Sexual strategies in plants IV. The distributions of gender in two monomorphic shrub populations

Abstract The gender of plants of populations of two New Zealand montane shrub species during two flowering seasons is described: Discaria toumatou has hermaphrodite flowers and Leptospermum scoparium is andromonoecious. Individuals in such species that are monomorphic for their sexual type are often considered to behave equally as pollen and ovule parents in sexual reproduction. Counts of the numbers of pollen- and fruit-bearing flowers on a sample of plants demonstrate, however, that in one season individuals within each population span the range from exclusively pollen- to predominantly ovule-contributors in functional gender (the proportions of genes that are likely to be transmitted through pollen and ovules, based on parental investments). The distribution of gender within a population changes somewhat between years but is basically consistent. Gender in successive years is not correlated among individuals within a population, indicating that the environment influences femaleness. Femaleness is not c...