Isolation and characterization of microsatellite loci from Lochmaea suturalis, the heather beetle (Coleoptera: Chrysomelidae), a pest in Europe and a biocontrol agent in New Zealand

The heather beetle Lochmaea suturalis which is native to northwest Europe has been released as a biocontrol agent for heather in New Zealand. We have isolated and optimized eight microsatellite loci from New Zealand beetles. These loci provide markers with high polymorphism ranging from four to 20 alleles per locus. Observed heterozygosity averaged 0.631 per locus. These results suggest the markers are useful for population studies that will contribute to assessment of L. suturalis as a biocontrol agent.     

Vegetative Production and Performance of

Aspects of the production and vegetative performance of Calluna vulgaris (heather) were examined in four areas of New Zealand between 1981 and 1983; Tongariro National Park in the North Island, together with Mount Cook National Park, the Wilderness Scientific Reserve, and Ben Callum peat bog in the South Island. The height and height/width quotient of Calluna bushes, the diameter increment of woody stems and the amount of flowers/stem all decreased with altitude. Other age-adjusted components of stem biomass were positively related to soil depth, soil moisture, soil organic content and soil pH. Biomass by direct harvest gave values between 300 g per m and 2200 g per m for plant communities with Calluna. These are similar Values to recorded from British and European heaths, although the contribution of Calluna to the total biomass was often less in New Zealand. Calluna from New Zealand has a higher proportion of wood relative to total biomass than is normally found in Britain and Europe and this is probably related to the management of British and European heaths by burning. Multiple regressions indicated that increased woodiness is associated with lower altitudes and deeper, moister soils. Woodiness tended to decrease on more organic and more acidic soils, with a corresponding increase in the proportion of green shoots. Flowering declined with increased altitude, while the proportion of green shoots relative to total biomass increased. It is suggested that the upward extension of Calluna within Tongariro National Park is limited mainly by constraints on flowering and sexual reproduction.     

The effect of heather beetle Lochmaea suturalis on vegetation in a wet heath in NE Scotland

An outbreak of heather beetle Lochmaea suturalis on a wet heath in north-east Scotland was monitored. In many respects, the outbreak was similar to those described in lowland heaths; it started at a particular locus and when the Calluna vulgaris was depleted, spread throughout the heath. Population size then decreased annually due to some undetermined exogenous factor. A contributory factor may be the high incidence (35%) of parasitoid infestation which is density independent and, thus, not controlling.
There is no evidence that the hairiness of the var. hirsuta of Calluna has an effect on herbivory by Lochmaea. The distribution of larvae through the canopy is neither influenced by the morphology of Calluna , nor by the associated species, and appears to be at random. This probably represents the distribution of eggs since little lateral migration of the larvae takes place.
The response of the vegetation to herbivory is not simple. Associated with decreased cover of Calluna is an increase in Sphagnum plumulosum and Hypnum jutlandicum and reduction in S. compactum and Pleurozium schreberi. Changes seem to depend on initial vegetation and other parameters not measured (e.g. proximity of propagules, microclimate). Regeneration of Calluna does occur, largely by layering; although seedling occurrence increases in some areas, especially in Sphagnum , it seems unlikely that this will make a major contribution to the recovery of Calluna.     

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.     

Heather and heathlands

GIMINGHAM, C. H., 1989. Heather and heathlands. Studies of the biology and ecology of heather (Calluna vulgaris (L.) Hull) reveal a remarkable combination of characteristics, accounting for its success as a heathland dominant and its ability to persist under traditional forms of use and management. New work on the life history and physiology of the species is helping to explain recent changes in heathlands, and to develop appropriate methods of conservation.     

Post-establishment assessment of host plant specificity of Arytainilla spartiophila (Hemiptera: Psyllidae), an adventive biological control agent of Scotch broom,Cytisus scoparius

Scotch broom, Cytisus scoparius (Fabaceae), is a shrub native to Europe that is invasive in the USA, New Zealand and Australia. The psyllid Arytainilla spartiophila has been purposely introduced to Australia and New Zealand as a biological control agent of C. scoparius, but is an accidental introduction to California. Lupines (Lupinus spp.) are the closest native taxon to Cytisus in North America, and are therefore considered to be at the highest risk for non-target damage. However, because no lupines are native to Australia or New Zealand, only one imported forage species was evaluated during prior host specificity testing. We conducted a laboratory nymphal transfer experiment, a field choice experiment and a field survey to assess risk to three lupine species (Lupinus albifrons, Lupinus bicolor and Lupinus formosus). In the laboratory, 20% of third-instar nymphs were able to develop to adulthood on L. formosus but not on the other lupine species, while 40% completed development on C. scoparius. In the field experiment, potted lupine and C. scoparius plants were placed beside large infested C. scoparius plants; oviposition occurred on all the potted C. scoparius plants, but on none of the lupines. In the field survey, no A. spartiophila eggs or nymphs were found on naturally occurring lupines growing adjacent to infested C. scoparius. The results indicate that A. spartiophila is not likely to damage or reproduce on lupines in the field. This study provides an example of how field studies can help clarify the host specificity of biological control agents.     

Chloroplast DNA diversity of Hieracium Pilosella (Asteraceae) introduced to New Zealand: reticulation, hybridization, and invasion

The European hawkweed Hieracium pilosella is a successful invader and a troublesome weed in New Zealand. The systematics of the genus Hieracium is extremely complex and contentious, probably due to recent speciation, hybridization, polyploidy, and diverse reproductive strategies. In the first chloroplast DNA survey of the group, we sequenced 285 plants (including H. pilosella and 12 other species of subgenus Pilosella) from New Zealand and Europe for 900 bp of trnL-trnF. Eleven haplotypes were identified with much sharing among species. Three haplotypes (A, D, G) were found in seven, three, and four species, respectively, but two species (H. lactucella and H. auricula) had single, private haplotypes. Our cpDNA data for subgenus Pilosella are consistent with the group's having incomplete lineage sorting and/or recent reticulate evolution. Six haplotypes were identified in H. pilosella, four of these unique to this taxon in our sample. In New Zealand, haplotype A was common and occurred in plants of different ploidy (i.e., 4×, 5×, 6×), whereas haplotypes C, B, and M were restricted to 4×, 5×, and 6× plants, respectively. The distribution of haplotype variation suggests that some or all of the H. pilosella seeds accidentally introduced into New Zealand probably came from east Europe rather than the United Kingdom and that a minimum of four lineages were introduced. Within New Zealand, hybridization of H. pilosella with a related taxon (probably H. praealtum) has occurred at least three times, involving both obligate sexual tetraploids and facultative apomictic pentaploids of H. pilosella.     

Transition from heathland to grassland initiated by the heather beetle

This paper discusses the transition from heather-dominated vegetation to one dominated by grass. The dominating species involved are Calluna vulgaris and Deschampsia flexuosa. The study covered three years, 1980–82, and was done at the Hoorneboeg heathland in the Netherlands. Several factors account for this transition: damage caused by the chrysomelid heather beetle Lochmaea suturalis Thomson, soil type, and interaction between beetle damage and Deschampsia when already present underneath or in the immediate vicinity of a Calluna canopy. There was a time-lag between beetle damage and grass establishment or expansion. In fact, this transition concerns a type of vegetation succession and can be treated as such. This succession therefore involves several causative factors external to the system Calluna-Deschampsia. The successional process is conceived as a stochastic one defined by transition probabilities which depend on a time component, a space component and a logistic response component. All these components are discussed in this paper, but the discussion of yet another component, the crowding of Deschampsia itself, will be treated separately.     

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).     

Effects of enhanced UVB on populations of the phloem feeding insect Strophingia ericae (Homoptera: Psylloidea) on heather (Calluna vulgaris)

Heather plants (Calluna vulgaris (L.) Hull) were grown for two years (April 1994–October 1996) under ambient or enhanced ultraviolet-B radiation (UVB: 280–315 nm), provided as a modulated treatment simulating a 15% ozone depletion (seasonally adjusted). Populations of the psyllid (Strophingia ericae (Curtis)) were measured before treatment and at yearly intervals thereafter. Before treatment there was no significant difference in the psyllid populations between treatments, or between the experimental and source populations. Enhanced UVB progressively produced a reduction in S. ericae populations compared with controls over 27 months. Analyses of C, N, total water soluble phenolics, total free amino acids and measurements of leaf angles and distances between leaflets demonstrated no effects of UVB treatment. However, concentrations of the amino acid isoleucine were lower (28%) in C. vulgaris exposed to the enhanced UVB treatment. Over the duration of the experiment the psyllid population structure at Lancaster changed from that typical of the upland site of origin (two-year cycle with overlapping cohorts) to a one-year life cycle typical of lowland sites, but this was independent of UVB treatments. Reduced isoleucine might explain the negative effects of elevated UVB on psyllid population numbers, but the precise effects of UVB on host chemistry and morphology are unknown. The problem of interpreting herbivore responses to enhanced UVB treatments in the field is discussed.     

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.     

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.     

Weta and the evolution of fleshy fruits in New Zealand

Fleshy fruits are typically coloured either red or black and are displayed in conspicuous locations where they can be easily located by birds. However, fleshy fruits in New Zealand are often white or translucently coloured and are displayed in the inner recesses of plant canopies. These characteristics have been attributed to coevolution with reptiles. I describe seed dispersal by a ground weta in Nelson lakes National Park, and hypothesise that the unusual characteristics of fleshy fruits in New Zealand may result from coevolution with weta.     

Review of invertebrate biological control agent regulation in Australia, New Zealand, Canada and the USA: recommendations for a harmonized European system

Europe lags far behind Australia, New Zealand, Canada and the USA in terms of implementing regulatory procedures for the import and release of invertebrate biological control agents (IBCAs). A number of standards, documents and guidelines have been produced over recent years in an attempt to harmonize regulation of IBCA introduction into Europe. Despite these efforts, the number of member countries implementing any form of IBCA regulation remains low, with many industries, biological practitioners and regulators fearing that a regulatory system would render the process of approval for IBCA introduction into a country costly and time consuming. Europe’s priority is therefore to formulate a regulatory system that will be readily approved of and adopted by all member countries. In this paper we review the current regulatory processes operating in Australia, New Zealand, Canada and the USA. There is potential for Europe to benefit from the years of experience that these countries have in IBCA regulation. We therefore propose recommendations based on features of the regulatory processes in each of the four countries that work well and that could be adopted to generate a workable Europe‐wide regulatory system.     

Management of heather for game and livestock

MOSS, R., 1989. Management of heather for game and livestock. Heather provides food and cover for moorland herbivores. Interactions between soils, drainage, climate, muirburn and grazing affect the species composition, structure and growth of moorland swards. Together, these aspects of a sward determine which and how many herbivores it can support. Grazing and burning maintain much heather ground which would otherwise revert to scrub or woodland. Heavy grazing by ungulates can turn a heathery sward into a graminaceous one, so reducing numbers of grouse and mountain hares. On good soils, invading graminoids are usually nutritious grasses and the carrying capacity for ungulates can increase. On poor soils, grazing and frequent burning may lead to swards dominated by poor quality grasses and sedges so that the carrying capacity for ungulates declines. One way of reinstating heather dominance is to remove livestock; where there are no heather plants left, other techniques may be necessary.     

Influence of target plant density on herbivorous insect oviposition choice: Ambrosia artemisiifolia L. (Asteraceae) and Zygogramma suturalis F. (Coleoptera: Chrysomelidae)

Zygogramma suturalis F. has been introduced to Russia for the biological control of the common ragweed Ambrosia artemisiifolia L. The functional response of Z. suturalis to the density of the target plant was studied at two levels: between plants and between 0.1 m² sampling plots. The number of Z. suturalis eggs per unit of plant weight was almost independent of plant weight, indicating that a functional response between plants is absent. However, tall and intermediate height plants received more eggs per phytomass unit than short plants. Between plots, correlation analysis showed that absolute Z. suturalis egg density is positively dependent on the ragweed density. Experiments showed that the locomotor activity of ovipositing females decreased when on the ragweed, suggesting orthokinesis. The number of leaf beetle eggs per unit of ragweed weight was negatively correlated with host plant density in May‐June, when the majority of eggs are laid, but was positively correlated in July and loosely, or not significantly, correlated in August. Seasonal changes in the functional response of a herbivorous insect to host plant population density have not been reported previously. A negative functional response of a herbivorous insect to target plant density can be a serious obstacle to the biological control of weeds.     

The invasive Australian redback spider, <Emphasis Type="Italic">Latrodectus hasseltii</Emphasis> Thorell 1870 (Araneae: Theridiidae): current and potential distributions,and likely impacts

Populations of the Australian redback spider, Latrodectus hasseltii Thorell 1870, were first recorded in New Zealand in the early 1980s and in Osaka, Japan in 1995. Reliable records suggest that naturalised populations of L. hasseltii in New Zealand are present only in Central Otago and New Plymouth. In Central Otago, L. hasseltii feeds on endangered invertebrates, such as Prodontria modesta (Broun 1909). Latrodectus hasseltii is also a hazard to the New Zealand endemic L. katipo through interbreeding and competitive displacement. CLIMEX^TM was used to model the potential global distribution of L. hasseltii based on current climate, and using ArcGIS^® 9.2, areas of suitable climate in New Zealand were overlaid with favourable habitats to identify areas most suitable for L. hasseltii establishment. In addition, shelter that urban areas offer L. hasseltii were modelled in CLIMEX and incorporated into ArcGIS to produce maps indicating cities and built up areas where the species could establish. The presence of L. hasseltii in New Zealand and Japan, and its possible spread to other areas, is of human health significance, and the species may also impact on native biodiversity.     

Chloroplast DNA diversity in Calluna vulgaris (heather) populations in Europe

Variation in the chloroplast genome of Calluna vulgaris (heather), the dominant species of northwest European heath communities, was analysed using polymerase chain reaction-restriction fragment length polymorphisms (PCR-RFLPs) and microsatellites. No length polymorphisms were detected in the 100-200 base pair (bp) fragments amplified by the conserved microsatellite primers, and sequencing revealed that the repeat regions were interrupted relative to the corresponding sequence in Nicotiana tabacum. In contrast, PCR-RFLP analysis revealed high levels of haplotype diversity within populations (hS = 0.443, hT = 0.842), as well as substantial differentiation between populations (GST = 0.473). Diversity and differentiation were higher in southern Europe than in northern Europe. Interpreted in the light of data from allozyme studies and pollen core records, the results suggest that the main glacial refugia for C. vulgaris were located in southwest Europe, including northern Spain, the Pyrenees and the Massif Central region of France. There is also evidence for diffuse survival of the species at more northerly latitudes.     

Preliminary evidence suggests that beech scale insect honeydew has a negative effect on terrestrial litter decomposition rates in

Honeydew production by New Zealand beech scale insects (Ultracoelostoma spp., Hemiptera: Margarodidae) is widely considered to have a positive influence on native animal abundance and ecosystem functioning. As a first assessment of whether there is a positive relationship between honeydew throughfall and litter decomposition rates, we placed experimental litter bags in each of 10 high and 10 low honeydew plots in mixed southern beech (Nothofagus) forest at each of two sites, Lakehead and Rotoiti, in the Nelson Lakes National Park. High and low honeydew plots were selected using sooty mould biomass on the forest floor as a surrogate for honeydew throughfall, as sooty mould biomass was shown to be strongly correlated (r = 0.906) with scale insect population size at the Rotoiti site. Contrary to our expectation, terrestrial litter decomposition was significantly lower in high honeydew plots than in low honeydew plots, at both Lakehead and Rotoiti. The presence of introduced wasps (Vespula spp., Hymenoptera: Vespidae) at the Lakehead site did not appear to have any significant effect on litter decomposition rates, despite the fact that wasps are thought to intercept much of the honeydew produced in this forest. Variance in litter decomposition rates between high and low honeydew treatments was predominantly determined by a direct relationship between sooty mould biomass and litter decomposition rate at the scale of individual litter bags. However, the mechanistic explanation for the observed relationship is unclear. Future studies should be directed towards quantifying the functional relationship between honeydew throughfall and growth rates of sooty mould, and their subsequent effects on abiotic conditions, microarthropod community dynamics and microbial activity rates in litter.     

The importance of viticultural landscape features and ecosystem service enhancement for native butterflies in New Zealand vineyards

The fragmentation of habitats in intensively managed farming landscapes is often considered to be partly responsible for butterfly population decline in Europe and the USA. Although relatively little is known about New Zealand butterfly ecology, agricultural landscapes in lowland New Zealand are managed similarly to those in Europe and ecosystem services (ES) in these landscapes are generally at a low level. In the northern hemisphere, attempts are being made to address the problem through agri-environment schemes, but such farmer compensation is not available in New Zealand. Instead, landowner- and research-led initiatives are currently the only potential approaches. One such project in the Canterbury province, New Zealand, is the Greening Waipara project. This aims to return native plants to viticultural landscapes and enhance ES, and while research has sought to quantify economic benefits of the project, there has been no work to establish if the plantings are improving or are likely to improve non-target invertebrate biodiversity, for example arthropods that are not biocontrol agents. In the first study of its kind in New Zealand, butterfly surveys were conducted in vineyards and linear mixed modelling techniques were used to identify the most important vegetation and structural features which may influence butterfly distribution. While the native planting areas were not important for butterflies, remnant patches of native vegetation in unproductive areas were vital for sedentary species. These results are discussed in relation to the conservation of native species in New Zealand vineyards and in the context of conservation in and around farmland in general.