A European pest to control a new zealand weed: investigating the safety of heather beetle, Lochmaea suturalis (Coleoptera: Chrysomelidae) for biological control of heather, Calluna vulgaris

Heather, Calluna vulgaris (L.) Hull, is a serious invasive weed in the central North Island of New Zealand, especially in Tongariro National Park, a World Heritage Area. Heather beetle, Lochmaea suturalis (Thomson), is a foliage-feeding pest of Calluna in Europe, that was selected as the most promising biological control agent for introduction into New Zealand, because it causes high levels of damage to Calluna in Europe. Host-range tests indicated that L. suturalis poses a negligible threat to native New Zealand plants. Cultivars of Calluna grown as ornamentals are suitable food plants, but are unlikely to be severely affected because L. suturalis requires a damp understorey of moss or litter for successful oviposition and pupation, which is rarely present in gardens. However, mosses and litter occurring under Calluna stands in Tongariro National Park are suitable substrates for eggs and pupae. Lochmaea suturalis released in New Zealand has been freed of parasitoids and a microsporidian disease that attack the beetles in Europe.     

The distribution of keratinophilic fungi in soils from New Zealand,and from two polynesian Islands

Summary (1) A total of 312 soils, 271 from New Zealand, 24 from Rarotonga, Cook Islands and 17 from Tokelau Islands was examined by the hair-baiting technique.(2)Microsporon gypseum was isolated from 1.5% of New Zealand soils and from 36.6% of Pacific Island soils. The difference in incidence in the two areas is significant.(3)Keratinomyces ajelloi andMicrosporon cookei were recovered from 52.8% and 7.7% of New Zealand soils respectively but neither species was isolated from the Island samples.K. ajelloi was found to be significantly associated with strongly acid soils, andM. cookei with a farmyard substrate.(4)Trichophyton terrestre was isolated from 1.1% of New Zealand and from 12.2% of Pacific Island soils. Two strains ofChrysosporium keratinophilum were isolated from New Zealand soils and an unidentifiedChrysosporium from one Rarotongan sample.(5) The distribution of the different species is discussed and compared with those reported in surveys carried out in other countries of the Southern Hemisphere. The effects of ambient temperature, and source and pH of the soil, on the distribution of keratinophilic fungi are considered, but there is insufficient detailed evidence to determine the importance of these factors in the ecology of these organisms.     

Dietary diversity in fruit-eating birds: a biogeographic comparison between New Zealand and Canada

If deterministic processes consistently structure ecological communities, similar patterns in species interactions should be observed in different geographic areas that experience similar environmental conditions. I tested for convergent patterns in dietary diversity of fruit-eating birds inhabiting similar latitude forests in the Northern and Southern hemispheres. I observed birds foraging for fruits over two fruiting seasons in both Nelson Lakes National Park, South Island, New Zealand, and the Pacific Rim National Park, Vancouver Island, Canada. I then conducted rarefaction analyses to compare community-level and species-level dietary diversity between geographic locales. Relationships between the size of each bird species and the average size of fruits consumed were also assessed. Results showed that the New Zealand bird community had greater overall dietary diversity than the Canadian community. However, similar levels of dietary diversity were observed among species within communities in both hemispheres. Positive relationships between bird size and fruit size were observed in New Zealand, but not in Canada. Therefore, while results showed some support for dietary convergence between hemispheres, several substantial differences were also observed, leading to mixed support for convergent patterns in the diets of fruit-eating birds between hemispheres.     

Suburban development and resultant changes in the vegetation of the bushland of the northern Sydney region

Bushland sites in the northern suburbs of Sydney were compared to sites in Brisbane Waters National Park, Ku-ring-gai Chase National Park and Royal National Park which are relatively unaffected by suburban development. Both shale-derived and sandstone-derived soil in four physiographical locations were examined, with three replicates of each of the 16 combinations. Phosphorus levels are higher in the soils of suburban sites compared to soils derived from similar rock bases in non-suburban sites. Phosphorus levels are also higher on shale-derived than on sandstone-derived soils, and lower on hilltops than in other physiographic positions. Suburban sandstone sites have soil phosphorus levels similar to those of non-suburban shale sites. Three major and three minor clusters of species were distinguished using a hierarchical agglomerative clustering. The major clusters consisted of (1) species commonly associated with wet sclerophyll forests and rainforest margins, (2) species directly or indirectly related to the presence of man, and (3) species associated with dry sclerophyll forests and heaths. Using analyses of variance and covariance, and logit models, the abundance of the first main cluster was related to nutrient-rich soils and the abundance of the third main cluster to low nutrient soils whereas the presence of the second main cluster was almost entirely restricted to sites surrounded by suburbs. The development of suburbs around vegetation patches has led to an increase in the abundance of native and exotic mesomorphic species and the addition of phosphorus to the soils. The data presented in this paper indicates that high phosphorus levels and presence of mesomorphic species are related.     

Colour preferences in North Island robins (

There is growing awareness and concern in New Zealand about native birds eating poisonous baits intended for pest species such as brushtail possums (Trichosurus vulpecula) and rats (Rattus rattus, R.,norvegicus, R. exulans). We investigated the colour preferences of North Island robins (Petroica australis) a species known to be vulnerable to poisoning. The main aims were to determine if: (1) robins had colour preferences, (2) the preferences were consistent between two separate populations and 3) the preferences were similar to those found previously in weka (Gallirallus australis), another native species. Robins in Pureora Forest Park and Te Urewera National Park were individually offered a choice between differently coloured versions of a novel food (red, yellow, brown, green, light blue and medium blue) daily, for six consecutive days. Robins showed food colour preferences pecking more at the red, yellow and green cake than the medium blue, light blue or brown cake. No difference was evident in the colour preferences of the two populations. The colour preferences of robins were similar to those reported previously with weka. Dyeing poisonous baits may be sufficient to stop a proportion of robins from eating them. Further work is needed to determine how colour preferences vary across seasons, populations and species.     

Growth pattern and distribution of biomass of Calluna vulgaris on an ombrotrophic peat bog

The distribution pattern of Calluna vulgaris on the ombrotrophic peat bog Åkhultmyren, S. Sweden, was investigated.
Calluna occurs primarily on hummocks, with its maximum biomass (ca 250 g m⁻² above ground, and ca 300 g m⁻² below ground) concentrated on hummock tops. Biomass decreased gradually along the hummock-hollow gradient to a level of ca 5 cm above the water level. This decreasing biomass was correlated with a decrease in the predominant age of the above ground shoots from 6–8 yr to 3–4 yr old shoots.
Calluna is characterized by extremely slow diameter growth and biomass increment. There was, however, a poor relation between height above water level and stem thickness, assimilating biomass and total shoot weight, respectively.     

Drainage, soil fertility and fire frequency determine composition and structure of gumland heaths in northern New?Zealand

Vegetation and soils were sampled at remaining gumland heath ecosystems in northern New?Zealand to determine vegetation patterns, environmental controls and major threats to long-term persistence. Classification and ordination techniques identified six vegetation types reflecting differences in drainage, rainfall, altitude, nutrients, and time since fire. Two modal types reflected opposite ends of the main environmental spectra. Leptospermum scoparium (Myrtaceae) shrubland occurred on relatively better drained sites with lower rainfall, altitude, and soil nutrient levels, whereas Gleichenia dicarpa (Gleicheniaceae) fernland typically occurred on more poorly drained sites with higher rainfall, altitude, and nutrient levels. Another widespread vegetation type dominated by both Leptospermum scoparium and Gleichenia dicarpa occupied plots of intermediate drainage, rainfall, altitude and nutrients. The three remaining types were of limited distribution and reflected uncommon combinations of environmental conditions or recent fire. Low soil nutrients in gumlands (mean total N = 0.182%, total P = 0.004%, oven-dry weight) are reflected in low Leptospermum scoparium foliage nutrients (mean total N = 0.858%, total P = 0.034%, δ¹⁵N = δ6.06‰, oven-dry weight) and slow growth rates (mean annual height growth rate = 11.90 cm year^?1), as in heathlands in Australia and South Africa. Gumlands are threatened by non-native plant species invasion, especially Hakea sericea (Proteaceae); habitat destruction for agricultural, industrial, and suburban development; and nutrient enrichment from adjacent agricultural land. Currently, fire is much less common in gumlands (mean time since fire = 18.4 years) than during early European settlement and some communities are apparently reverting to forest. Research to investigate the use of fire as a management tool is recommended for long-term conservation of New?Zealand gumlands.     

Possible Mechanism for Spontaneous Establishment of Calluna vulgaris in a Recently Abandoned Agricultural Field

In Western Europe, arable lands have been abandoned to increase the area of nature, such as Calluna vulgaris –dominated heathlands. However, the growth conditions, e.g., nutrient availability and lack of a phenolics-rich organic layer, on ex-arable sandy soils differ markedly from those of heathland and will favor fast-growing plant species. Succession toward Calluna -dominated heathland is expected to take decades unless intensive restoration management is applied. Here, we report a possible mechanism to explain the occurrence of Calluna patches (0.7–2.0 m diameter) in a 10-year abandoned agricultural field within a dominant vegetation of grasses and forbs. All roots sampled from the Calluna patches were colonized by ericoid mycorrhizal (ERM) and other endomycorrhizal fungi. Both nitrogen mineralization of soil organic N and potential nitrogen mineralization (arginine ammonification) were much lower in soil under Calluna patches than in the rest of the ex-arable soil, although other soil characteristics did not differ. The nitrogen to phosphorus ratio in Calluna shoots was much greater than that in shoots of grasses and forbs, indicating that the latter were more N limited. The results indicate that the association with ERM fungi is probably providing the host competitive superiority for nitrogen even in a soil with low organic matter content. Our results suggest that the conversion from arable land into heathland may be accomplished by the immediate establishment of Calluna seedlings and ERM inoculum when agricultural activities are stopped. This needs to be tested in controlled experiments.     

Digging the New York City Skyline: Soil Fungal Communities in Green Roofs and City Parks

In urban environments, green roofs provide a number of benefits, including decreased urban heat island effects and reduced energy costs for buildings. However, little research has been done on the non-plant biota associated with green roofs, which likely affect their functionality. For the current study, we evaluated whether or not green roofs planted with two native plant communities in New York City functioned as habitats for soil fungal communities, and compared fungal communities in green roof growing media to soil microbial composition in five city parks, including Central Park and the High Line. Ten replicate roofs were sampled one year after planting; three of these roofs were more intensively sampled and compared to nearby city parks. Using Illumina sequencing of the fungal ITS region we found that green roofs supported a diverse fungal community, with numerous taxa belonging to fungal groups capable of surviving in disturbed and polluted habitats. Across roofs, there was significant biogeographical clustering of fungal communities, indicating that community assembly of roof microbes across the greater New York City area is locally variable. Green roof fungal communities were compositionally distinct from city parks and only 54% of the green roof taxa were also found in the park soils. Phospholipid fatty acid analysis revealed that park soils had greater microbial biomass and higher bacterial to fungal ratios than green roof substrates. City park soils were also more enriched with heavy metals, had lower pH, and lower quantities of total bases (Ca, K, and Mg) compared to green roof substrates. While fungal communities were compositionally distinct across green roofs, they did not differentiate by plant community. Together, these results suggest that fungi living in the growing medium of green roofs may be an underestimated component of these biotic systems functioning to support some of the valued ecological services of green roofs.     

Community reassembly: a test using limestone grassland in New Zealand

To examine community reassembly, we sampled grasslands on calcareous soil (4%–24% CaCO₃) in New Zealand that were largely composed of species introduced from Britain. We tested whether the British species had reassembled on New Zealand limestone into the same communities as they form on limestone in Britain. The vegetation of six New Zealand sites was sampled, each with ten 2 × 2 m quadrats that followed the standard methodology of the British National Vegetation Classification (NVC). Analysing species presence and cover using program TableFit with the full database of British species, the New Zealand species assemblages gave poor to moderate fits (40%–72%) to the communities of the NVC, and even then not to calcareous grassland, though one site did fit to a calcareous spring community. The poor fits can be partly attributed to the absence from New Zealand of many British calcareous-specialist species. On omitting from the NVC database all species not present in New Zealand, the fits increased somewhat to 48%–77%. Using this modified database, two sites fitted British calcareous grassland communities. These two sites are on thinner soil (<10 cm depth), under lower rainfall. Where fits were obtained to calcareous communities, the environment of the community in Britain matched very well that of the New Zealand site. It is concluded that environmental and perhaps biotic filtering has been strong enough in some sites to assort alien species into the same species assemblages as they form in their native range, indicating the Deterministic model of community structure. However, the absence of some species has prevented full reassembly.     

Patterns of tree community composition along a coastal dune chronosequence in lowland temperate rain forest in New Zealand

Soil chronosequences provide an opportunity to examine the influence of long-term pedogenesis on the biomass and composition of associated tree communities. We assessed variation in the species composition of trees, saplings, and seedlings, and the basal area of adult trees, in lowland temperate rain forest along the Haast chronosequence on the west coast of the South Island of New Zealand. The sequence consists of Holocene dune ridges formed following periodic earthquake disturbance and is characterized by rapid podzol development, including a marked decline in phosphorus concentrations, accumulation of a thick organic horizon, and formation of a cemented iron pan. Tree basal area increased for the first few hundred years and then declined in parallel with the decline in total soil phosphorus, consistent with the concept of forest retrogression. There were also marked changes in the composition of the tree community, from dominance by conifers on young soils to a mixed conifer?Cangiosperm forest on old soils. Although a variety of factors could account for these changes, partial Mantel tests revealed strong correlations between tree community composition and soil nutrients. The relationships differed among life history stages, however, because the adult tree community composition was correlated strongly with nutrients in the mineral soil, whereas the seedling community composition was correlated with nutrients in the organic horizon, presumably reflecting differences in rooting depth. The changes in the tree community at Haast are consistent with disturbance-related succession in conifer?Cangiosperm forests in the region, but the opposite of patterns along the nearby Franz Josef post-glacial chronosequence, where conifers are most abundant on old soils. The Haast chronosequence is therefore an important additional example of forest retrogression linked to long-term soil phosphorus depletion, and provides evidence for the role of soil nutrients in determining the distribution of tree species during long-term succession in lowland temperate rain forests in New Zealand.     

Dams, ducks and DNA: identifying the effects of a hydro-electric scheme on New Zealand's endangered blue duck

Blue duck are conspicuous inhabitants of headwatersections of many rivers in the central North Island of NewZealand. These rivers are also home to a number ofhydro-electricity dams. One scheme in particular – the TongariroPower Development (TPD) involves the reduction and diversion ofwater flow from the headwaters of the Whakapapa, Whanganui andTongariro Rivers in the central North Island of New Zealand. Numbers of the endangered blue duck (Hymenolaimus malacorhynchos)on the Tongariro River have declined markedly in the last decade. Opinions have differed as to whether this indicated a reductionin the `health' of the population or simply a reduction in thecarrying capacity of the river. The issue centered aroundwhether the Tongariro River population was still self-sustaining,or reliant upon immigration from other source rivers. DNAmarkers were used to estimate the relative contributions tooverall recruitment of production from within the population andmigration from external sources. Up to 11 birds were collectedfrom one unmodified population, two stable modified populationsand one declining population. DNA fingerprinting results from twomultilocus probes were analysed using a one-way ANOVA and showedthat mean bandsharing among individuals from the Tongariro River(0.19) was significantly lower than values recorded from thethree other rivers (0.37–0.39). Discovery curves alsoindicated that the Tongariro population contains more geneticvariation than the other three. These results suggest that theTongariro River population is a `sink' dependent upon immigrationfrom a number of different source populations, rather than localproduction.     

Regeneration patterns in a Central European dry heathland: effects of burning,sod-cutting and cutting

Vegetation development in dry heathlands was studied during a six-year period following experimental burning, sod-cutting and cutting in a continental area in the southern part of the Czech Republic (Podyjí National Park). Calluna vulgaris-dominated heathlands in the area were composed of uneven-aged stands and had been unmanaged for several decades. The aim of the study was testing the applicability of Western European management systems to nature conservation in a continental area. Species composition was recorded in 8 permanent plots using 25×25 cm grids, and vegetation recovery following different treatments was analysed. Calluna recovered successfully after burning. Burning dense heathlands, which contained a large amount of woody fuel, resulted in a medium-intensity fire that destroyed moss mats and litter and exposed patches of bare ground to facilitate Calluna regeneration by seed, in addition to vegetative regrowth. On the contrary, in open heathlands with patches of herbaceous vegetation, low-intensity fires which failed to expose mineral soil were more typical. Almost all Calluna regeneration was vegetative in this case, and regrowth was slower. Heathland recovery after sod-cutting to mineral soil depended on whether or not Calluna seed germination occurred in the plot. With germination, the community developed towards heathland; without towards grassland. Cutting promoted a striking increase in grass cover, which was followed by the slow recovery of Calluna. The experiments suggest that of these management systems, burning is perhaps the most appropriate in the study area. A nature conservation management system is proposed, based on sheep grazing combined with rotational burning of restricted patches.     

Mitochondrial haplotypes and the New Zealand origin of clonal European Potamopyrgus, an invasive aquatic snail

The small aquatic snail Potamopyrgus antipodarum is an important invading species in Europe, Australia and North America. European populations are generally believed to derive from accidental introductions from New Zealand, probably dating back to the mid-19th century. We have employed mitochondrial DNA sequences to test the proposed New Zealand origin of European Potamopyrgus, and to learn more about its genealogical history. Using a 481-bp region of the 16S ribosomal RNA gene, we identified 17 distinct haplotypes among 65 snails from New Zealand. In marked contrast, only two haplotypes were found across all European samples, which cover a large geographical area. Importantly, these two haplotypes are shared with snails from the North Island of New Zealand. Due to sampling limitations we cannot rule out a South Island origin for one of the haplotypes, but our results clearly demonstrate the New Zealand origin of European populations. The marked divergence among the two European haplotypes implies the successful colonization by two distinct mitochondrial lineages, which is consistent with previous data based on nuclear markers.     

Interaction between Some Pasture Species and 2

Possible control options are investigated for the introduced Hieracium weeds, particular problems in South Island high country, New Zealand. In a pot experiment regression of input to output ratios of above ground biomass over successive harvests, from binary mixtures was used to determine the competitive interaction between 13 pasture species and two Hieracium species, H. pilosella and H. praealtum, in a low fertility soil. Treatments also included a factorial of presence or absence of compartments separating root and shoots of species. Species differed in their mean growth rate, relative to Hieracium species. The ranking of mean growth rate relative to H. pilosella was Trifolium repens (best), Bromus inermis, Sanguisorba minor, Festuca novaezelandiae, F. rubra, Arrhenatherum elatius, Anthoxanthum odoratum, Lotus corniculatus, Hypochoeris radicata, Trifolium repens, T. hybridum, T. medium and Astragalus cicer. Shoot partitions decreased Hieracium's interaction with white clover while root partitions increased interaction with B. inermis. However, the rates were not related to the proportion of Hieracium in the mixtures, indicating a general lack of specific competitive effects against Hieracium.     

Invertebrate survey of coastal habitats and podocarp forest on Ulva Island,Rakiura National Park,New Zealand

Abstract

Inventory of the invertebrate fauna is important to establish taxonomic diversity, abundance and distribution, and hence the conservation of indigenous biodiversity. Invertebrate assemblages have been documented in some broadleaf‐podocarp forests and grassland habitats in New Zealand, but not in dense stands of coastal forest or in mature podocarp forest. This survey aimed to provide a taxonomic inventory of terrestrial invertebrates and their habitat associations on Ulva Island (Rakiura National Park, Stewart Island), an off‐shore sanctuary of significant conservation value in New Zealand. We systematically documented the invertebrate assemblages collected in ground litter and on tree trunks on the island. The invertebrate specimens identified represented 4 phyla, 6 classes, 25 orders and 62 species. The invertebrate fauna reported in this survey was distinct from those of lowland shrubland and broadleaved‐Nothofagus forests on the mainland, but shared species with that reported from another similar off‐shore island, Codfish Island (Whenua Hou).     

Experimental archaeology gardens assessing the productivity of ancient Māori cultivars of sweet potato, Ipomoea batatas [L.] Lam. in New Zealand

This paper presents estimates of yield for effort of the cultivar, ‘Taputini,’ which is sweet potato that was eaten by the Māori of New Zealand before European contact in the 18th century. The two experimental archaeology gardens were planted at sites on either side of Cook Strait: the one with clay soils is on the South Island at Robin Hood Bay; the one with sandy soils is at Whatarangi on the North Island. The records of labor input required to cultivate these gardens over seven years for Robin Hood Bay and six years for Whatarangi compared with crop yields provide data on the economics of pre-European kũmara gardening. Also reported are some of the properties of the soil. These gardens produced an average of 12 metric tons (1,000 kilograms=1 metric ton) per hectare (ha), which is not much less than contemporary yields for modern cultivars and 3 to 4 times most previous estimates of pre-European production.     

Genetic differentiation of starling (Sturnus vulgaris: Aves) populations in New Zealand and Great Britain

Several hundred starlings (Sturnus vulgaris) were introduced to New Zealand from Great Britain during1860–1880. Allozymic variation at 24 loci was analysed in winter populations sampled at six localities in each country. New Zealand samples had fewer alleles per locus but the same mean heterozygosity (3% per locus) and proportion of polymorphic loci as did British samples. Winter populations in Britain contain European migrants and were genetically homogeneous. Paradoxically, genetic distances among derived New Zealand populations, and between New Zealand and Great Britain were much greater, similar in magnitude to those observed among allopatric populations in other avian species. The geographical pattern of genetic variation in New Zealand suggests that reproductive isolation of populations and random drift have contributed to the development of population differentiation.     

Biomass allocation, shade tolerance and seedling survival of the invasive species

Berberis darwinii (Berberidaceae) is a serious environmental weed in New Zealand, capable of invading a range of different light environments from grazed pasture to intact forest. According to optimal partitioning models, some plants optimise growth under different environmental conditions by shifting biomass allocation among tissue types (e.g. roots, shoots) to maximise the capture of limiting resources (e.g. water, light). We examined patterns of growth, biomass allocation, and seedling survival in Berberis darwinii to determine whether any of these factors might be contributing to invasion success. Growth and biomass allocation parameters were measured on seedlings grown for 7 months in five natural light environments in the field. Survival was high in the sunniest sites, and low in the shadiest sites. Seedlings grown in full sun were an order of magnitude taller and heavier, had five times as many leaves, and proportionally more biomass allocated to leaves than seedlings grown in other light environments. In the shade, leaves were bigger and thinner, and leaf area as a proportion of total plant biomass increased, but the proportion of above- to below-ground biomass was similar across all light and soil moisture environments. In summary, although leaf traits were plastic, patterns of biomass allocation did not vary according to optimal partitioning models, and were not correlated with patterns of seedling survival. Implications for the management of this invasive species are discussed.