Papers by Nicholas Dickinson
Soil ecology letters, Jan 18, 2024
New Zealand Journal of Ecology, 2017
Important knowledge gaps remain with regards to the ecology and the systematics of New Zealand's ... more Important knowledge gaps remain with regards to the ecology and the systematics of New Zealand's native earthworms. With many putative new species yet to be described, often specimens cannot be named, which makes species inventory, monitoring and community comparisons difficult. Our work aimed to identify new putative taxa of New Zealand native species of earthworms, and describe their distribution in selected human-modified ecosystems. A total of 24 earthworm taxa (13 native and 11 exotic) were identified using a DNA barcoding approach focusing on 16S rDNA and COI (cytochrome oxidase subunit 1). The combination of morphological and molecular analyses were complementary in elucidating species identity. However, of the 13 native taxa, eight could not be named and are likely to be undescribed species from the genera Octochaetus, Maoridrilus and Deinodrilus. Most native species appeared to have a restricted geographic distribution linked to soil conditions, in particular pH and organic matter.
Research Square (Research Square), Aug 5, 2022
Background Experimental work using pot trials and mesocosm studies has indicated that species com... more Background Experimental work using pot trials and mesocosm studies has indicated that species combinations are more effective in mitigating the soil nutrient constraints that limit pasture productivity in New Zealand's hill country, but there is little eld evidence to support this. Aim We question whether coexistence of species provides an opportunity to facilitate enhanced uptake and improved procurement of key soil nutrients by assemblages of plants in these mid-altitude grasslands. Methods Native and exotic legumes and co-occurring plant species were sampled according to whether they were growing together in close proximity or in single species patches. Foliar concentrations of nutrients were compared. Results Uptake of nutrients by a native broom, Carmichaelia petriei, was enhanced when it was growing in combination with native tussock grasses. Enhanced uptake of eight nutrients was recorded in foliage of an exotic legume, Lotus pedunculatus, when it was growing with native grasses or within the acuminate foliage of Aciphylla aurea (golden spaniard). Foliar concentrations of only P and Mn were elevated in white clover (Trifolium repens) foliage when it was growing in combination with grasses. Overall, mutual facilitation of nutrient uptake by combinations of species growing together was in evidence. Conclusions Some species that are less desirable from an agricultural perspective may improve acquisition of soil nutrients by the plant community. Novel native species assemblages represent an opportunity to re ne pasture management. Exploiting combinations of plant species that facilitate optimal exploitation of nutrients could reduce fertiliser requirements, enhancing and protecting biodiversity in pastoral grasslands.
Journal of Agriculture and Forestry University
Wheat bug, Nysius huttoni, is considered as an economic pest of forage Brassicas and many other c... more Wheat bug, Nysius huttoni, is considered as an economic pest of forage Brassicas and many other cultivated crops, such as wheat, kale, and vegetables in New Zealand. Insecticides- as seed coatings and sprays are frequently used to manage this pest, but a high proportion of these insecticidal compounds enter the soil and leads to pesticide resistance, and they may impact beneficial arthropods and soil microorganisms, creating an adverse effect on ecosystem services (ES). In this paper, we discuss a technology, that we have developed to trap , for example, wheat bug away from kale seedlings, and integrating these in less susceptible kale cultivars that can potentially reduce over-reliance on orthodox pesticides on brassicas. Laboratory studies were conducted to screen the suitable trap crop among nine other plants (alyssum, wheat, phacelia, buckwheat, coriander, white clover, alfalfa, and kale) mainly by considering growth stages (vegetative and flowering), and select less susceptible...
Background Combination of grasses and nitrogen-fixing legumes are ubiquitous in most natural and ... more Background Combination of grasses and nitrogen-fixing legumes are ubiquitous in most natural and derived pastoral grasslands. This was not formerly the case in New Zealand’s unique indigenous grasslands that are now frequently impacted by exotic pasture grasses and legumes. Understanding the co-existence of native and exotic plants is the broad focus of this research.Aims Spillover of nitrogen (N) from clovers to grasses in diverse pasture is well known. We question whether grasses provide reciprocal nutritional benefits to legumes. Does the mutual exploitation of soil biogeochemistry by legumes and grasses help to explain their coexistence and, if so, does this have implications for biodiversity in NZ’s novel native grassland communities? Methods Combinations of grasses and legumes, including a native tussock grass, were grown in a nutrient-poor high country soil (low P, S, Ca, Mg, Mn, and B) in a pot experiment, quantifying the foliar acquisition of nutrients from soil. Foliage of...
NATO Science Series
Phytoextraction of Cd using Salix is likely to be suitable only for urban and agricultural soils ... more Phytoextraction of Cd using Salix is likely to be suitable only for urban and agricultural soils with low-level contamination; unrealistically long time scales make this unsuitable for mine spoils or heavily contaminated Industrial sites. Under short-rotation coppice, willows can be expected to have a productive lifecycle of about 30 years. After this period the root bole could be relatively easily removed. It would also be important to harvest foliage. Shortrotation coppice systems in northern Europe generally rely on harvesting the trees during winter, often when the ground is frozen to provide easier access for agricultural machinery. However, in terms of metal removal, a substantial proportion of Cd is relocated to the foliage; leaf fall in autumn may actually increase the concentration and availability of the metal in the surface and would require earlier harvesting along with the woody stems.
1. Kānuka (Kunzea serotina, Myrtaceae) dryland shrubland communities of the lowland plains of Sou... more 1. Kānuka (Kunzea serotina, Myrtaceae) dryland shrubland communities of the lowland plains of South Island (Te Wai Pounamu) New Zealand (Aoteoroa) contain a ground cover largely consisting of mosses, predominantly Hypnum cupressiforme. There has been no previous study of the role of mosses in this threatened habitat which is currently being restored within a contemporary irrigated and intensively-farmed landscape that may be incompatible with this component of the ecosystem. 2. The aim of the present study was to investigate the influence of moss ground cover on hydrology, nitrogen (N) availability and vascular plant interactions, and in relation to nutrient spillover from adjacent farmland. Experimental work was a combination of glasshouse experiments and field-based studies. 3. Extremes of soil temperature and moisture were found to be mediated by the moss carpet, which also influenced N speciation; available N declined with moss depth. The moss layer decreased the amount of germi...
Restoration Ecology, 2016
SB conceived the study, coordinated the sampling and wrote the manuscript; SB, YNK conducted mole... more SB conceived the study, coordinated the sampling and wrote the manuscript; SB, YNK conducted molecular analyses and identified the specimens based on morphology; SB, YNK, MB, NMD collected and hand sorted the specimens in the field; SB, MCL performed the statistical analyses; SB, YNK, MB, MCL, NMD edited the publication.
Journal of Economic Entomology, 2018
Nysius huttoni is an endemic New Zealand insect pest. Its feeding can seriously reduce crop estab... more Nysius huttoni is an endemic New Zealand insect pest. Its feeding can seriously reduce crop establishment in forage brassicas. A series of choice, no-choice and paired-choice tests were conducted in a controlledtemperature room to evaluate the pest's host preferences on seedlings of eight plant species: Lobularia maritima (alyssum), Triticum aestivum (wheat), Phacelia tanacetifolia (phacelia), Fagopyrum esculentum (buckwheat), Coriandrum sativum (coriander), Trifolium repens (white clover) and Medicago sativa (alfalfa), and Brassica oleracea (kale) as a potentially susceptible control. In choice tests, wheat was the most preferred followed by alyssum, buckwheat and phacelia, all being significantly more favoured than kale. Survival rate of wheat bugs over 120 h was: on phacelia (71.0%), clover (69.0%), alyssum (48.0%) and wheat (47%), which were all significantly higher than on kale seedlings. Alyssum and wheat were more susceptible to N. huttoni feeding damage than were other tested plants. High survival rates were recorded in paired choice tests on kale and alyssum (78.3%) compared with the other paired choice tests. The implications of these findings are important for developing ecological management strategies in, or around, forage brassica fields.
Soil Biology and Biochemistry, 2006
Planting trees to stabilize metalliferous mine tailings is a widely used form of land reclamation... more Planting trees to stabilize metalliferous mine tailings is a widely used form of land reclamation although substantial soil amendment is invariably required, both to improve the physico-chemical status of the tailings and to ameliorate toxicity prior to planting. Here, we report a glasshouse study of the combined effects of burrowing earthworms (Pheretima guillelmi) and arbuscular mycorrhizal fungi (Glomus spp., AMF) on establishment of a naturally invasive, woody, nitrogen-fixing legume, Leucaena leucocephala, on topsoil-amended Pb/Zn mine tailings. AMF provided the most effective preliminary inoculant, improving N, P and K uptake, but earthworms had more influence improving N nutrition. In most cases, the combined effects of AMF and earthworms were additive and proved to be beneficial to plant growth, plant nutrition and for protection against uptake of toxic metals. AMF influenced metal uptake more than earthworms, but together they reduced mobility of Pb and Zn in soil by as much as 25%. Some minor but significant negative interactions were also evident; for example, earthworms enhanced soil microbial activity but inhibited the beneficial effects of AMF on N 2 -fixation. We argue that increased attention to ecological interactions in soil could reduce costs and improve the efficacy of restoring a vegetation cover to land impacted by contaminated spoils.
Forest Ecology and Management, 2004
A large-scale field experiment on 11 closed old-style landfill sites aims to identify the constra... more A large-scale field experiment on 11 closed old-style landfill sites aims to identify the constraints to tree survival and growth, and the opportunity for restoration to community forestry. This paper analyses survival and growth during the first 3 years. A preliminary site investigation showed that the main environmental constraints to tree growth were soil depth, site exposure, soil compaction, waterlogging and low soil oxygen. None of the sites were suitable for forestry according to current guidelines. Thirty-nine plots (mostly 40 m  40 m) at the 11 landfill sites were each planted with 21 woody species, amounting to 8 ha of experimental plots within 14 ha of buffer zone planting. All planting stock was of the same origin, planted at the same time in a randomised-block design. Despite herbicide applications, weed competition had the largest inhibitory effect on establishment in the first year. Patterns of survival and growth were contradictory; often species with poor survival rates grew well and vice versa. The most successful species were late successional species (compared to pioneers), native species (compared to exotics), shrubs (compared to trees) and broadleaves (compared to conifers). Eight of the 21 species could be recommended to be good general choices for landfill sites. It is concluded that all sites were suitable for community forestry, although two sites would require additional soil amendment. Species recommendations to suit a particular range of environmental determinants at other landfill sites is complicated by the mound-like shape of landfills and a high degree of within-site and within-plot variability; this was a more important determinant of mortality and growth than was the particular species planted. Differences between plots were reflected in mortality data, whereas growth data separated differences between species. Monitoring of the plots and further experimental work at the sites will continue for at least 15 years.
Frontiers in Plant Science, 2019
Root foraging may increase plant nutrient acquisition at the cost of reducing the total volume of... more Root foraging may increase plant nutrient acquisition at the cost of reducing the total volume of soil explored, thereby reducing the chance of the roots encountering additional patches. Patches in soil seldom contain just one nutrient: the patch may also have distinct textural, hydrological, and toxicological characteristics. We sought to determine the characteristics of root foraging by a pioneering species, Leptospermum scoparium, using pot trials and rhizobox experiments with patches of biosolids. The growth of L. scoparium was increased by <50 t/ha equiv. of biosolids but higher doses were inhibitory. Roots foraged patches of biosolids in a low-fertility soil. There was no evidence of chemotaxis, rather, the roots proliferated toward the patch of biosolids, following chemical gradients of nitrate. While the biosolids also contained high concentrations of other nutrients (P, K, and S), only significant chemical gradients of nitrate were found. Once the roots encountered a patch of biosolids, the growth of the plant increased to a level similar to plants growing in soil homogeneously mixed with biosolids or surface-applied biosolids. Our results indicate that roots forage nitrate, which is mobile in soil, and that gradients of nitrate may lead to patches containing other less mobile nutrients, such as phosphate or potassium.
Below-ground invasion, the coexistence of exotic and endemic earthworms in New Zealand soils
Foods
Soil properties in the foraging range of honeybees influence honey composition. We aimed to deter... more Soil properties in the foraging range of honeybees influence honey composition. We aimed to determine relationships between the antimicrobial properties of New Zealand mānuka (Leptospermum scoparium) honey and elemental concentrations in the honey, plants, and soils. We analyzed soils, plants, and fresh mānuka honey samples from the Wairarapa region of New Zealand for the chemical elements and the antimicrobial activity of the honey as indicated by methylglyoxal (MGO) and dihydroxyacetone (DHA). There were significant negative correlations between honey MGO and the concentrations of Mn, Cu, Mg, S, Na, Ba, K, Zn, and Al. These elements may provide a low-cost means of assessing mānuka honey quality. For individual elements, except for K, there were no correlations between the honeys, plants, and soils. Soil nitrate concentrations were negatively correlated with concentrations of MGO and DHA in the honey, which implies that soil fertility may be a determiner of mānuka honey quality.
Arsenic mobility and bioavailability in flooded industrially polluted UK soils
Land Contamination & Reclamation, Dec 1, 2010
Abstract There is a paucity of studies focusing on the fate of arsenic (As) in poorly drained per... more Abstract There is a paucity of studies focusing on the fate of arsenic (As) in poorly drained peri-urban land or clay-lined landfills. Evidence from rice paddy soils would indicate enhanced mobility and bioavailabil-ity of this metalloid in soils with impeded drainage. The fate of ...
Soil phosphorus dynamics along a short‐term ecological restoration trajectory of a coastal sandplain forest in New Zealand
Land Degradation & Development, 2020
We aim to understand the impact of ecological restoration on soil biogeochemistry, and the interr... more We aim to understand the impact of ecological restoration on soil biogeochemistry, and the interrelationship between vegetation and soil phosphorus. In a study of two different‐aged soils in coastal New Zealand, soils are described along a transition from abandoned agricultural pasture, through 6‐year old restoration plots, towards forest fragments that have been largely undisturbed for 75 and 166 years. Soil biogeochemistry varied spatially along this restoration trajectory; there were profound changes in surface soil, but little impact on deeper soil horizons. In the early stages, soil organic matter accumulation and decomposition, and increasing demand of N from fast‐growing plants corresponded with rapid nutrient mineralization. Loss of soil total P, an increase of occluded P, and the increasing importance of soil organic P as soils weathered and aged, supported conceptual models of longer‐term soil pedogenesis. There was no evidence that the success of the establishment of plan...
Journal of Soils and Sediments, 2020
Purpose Microplastics have been widely reported to contaminate aquatic environments, particularly... more Purpose Microplastics have been widely reported to contaminate aquatic environments, particularly impacting marine organisms, but little is known of microplastic contamination of the soil environment. This study compared the distribution of microplastics in forest, urban, and agricultural soils, investigating the reasons for differences in abundance associated with land use. We analyzed distribution and abundance of microplastics in 100 soils, representing different land use types that include forest, urban (traffic and residence), and agriculture the environs of Yeoju City. Sampling plots were located on a systematic grid with 2.5 km × 2.5km spacing. Topsoil (0-5 cm) was collected with a hand auger and samples were pretreated by drying, density separation using ZnCl 2 solution, organic matter digestion, and decompression filtration. Abundance of microplastics was measured by counting using a digital stereo microscope; microplastics were grouped by shapes (fragment, film, fiber, and sphere) and color (black, red, green, blue, yellow, white, and transparent). Fourier-transform infrared spectroscopy (FT-IR) analysis was used to identify polymer type of the microplastics. Results and discussion Soils of Yeoju contained an average 700 pieces•kg -1 of microplastics, but this greatly varied with land use types. Roadside soils had more microplastics (1108 pieces kg -1 ), mostly black styrene-butadiene rubber (SBR) fragments associated with tire dust. Unexpectedly, the largest amount of microplastics was detected not from urban soils but from an upland soil (3440 pieces kg -1 ). The mean abundance of microplastics in agricultural soil was 664 pieces kg -1 , varying with farming types; the highest abundance was at orchard sites, followed by upland, greenhouse, and then paddy field sites. Polyethylene (PE) and polypropylene (PP) were identified from microplastics sampled at upland, greenhouse, and orchard sites, while SBR-derived microplastics were found more widely in all farmland soils, implicating that mulching film usage and farm machinery. Conclusions Soil microplastic contamination is significant and widespread in urban and agricultural soils of Yeoju, but differs in form and distribution, according to the locality of traffic and farming. Atmospheric fallout to forest soils is quantified and found to be significantly impacted by microplastics. The use of mulching film as a source of PE and PP presents particular concern in terms of the effects of microplastic contamination on soil quality, health, and functionality in agroecosystems.
Journal of Plant Nutrition and Soil Science, 2018
Approximately 40% of New Zealand's land mass is fertilized grassland with entirely non‐native... more Approximately 40% of New Zealand's land mass is fertilized grassland with entirely non‐native plants, but currently there is substantially increased interest in restoration of native plants into contemporary agricultural matrices. Native vegetation is adapted to more acid and less fertile soils and their establishment and growth may be constrained by nutrient spillover from agricultural land. We investigated plant–soil interactions of native N‐fixing and early successional non N‐fixing plants in soils with variable fertility. The effects of soil amendments of urea (100 and 300 kg N ha−1), lime (6000 kg CaCO3 ha−1), and superphosphate (470 kg ha−1) and combinations of these treatments were evaluated in a glasshouse pot trial. Plant growth, soil pH, soil mineral N, Olsen P and nodule nitrogenase activity in N‐fixing plants were measured. Urea amendments to soil were not inhibitory to the growth of native N‐fixing plants at lower N application rates; two species responded positivel...
Applied Geochemistry, 2017
Numerous studies have shown that urban soils can contain elevated concentrations of heavy metals ... more Numerous studies have shown that urban soils can contain elevated concentrations of heavy metals (HMs). Christchurch, New Zealand, is a relatively young city (150 years old) with a population of 390,000. Most soils in Christchurch are sub-urban, with food production in residential gardens a popular activity. Earthquakes in 2010 and 2011 have resulted in the re-zoning of 630 ha of Christchurch, with suggestions that some of this land could be used for community gardens. We aimed to determine the HM concentrations in a selection of suburban gardens in Christchurch as well as in soils identified as being at risk of HM contamination due to hazardous former land uses or nearby activities. Heavy metal concentrations in suburban Christchurch garden soils were higher than normal background soil concentrations. Some 46% of the urban garden samples had Pb concentrations higher than the residential land use national standard of 210 mg kg À1 , with the most contaminated soil containing 2615 mg kg À1 Pb. Concentrations of As and Zn exceeded the residential land use national standards (20 mg kg À1 As and 400 mg kg À1 Zn) in 20% of the soils. Older neighbourhoods had significantly higher soil HM concentrations than younger neighbourhoods. Neighbourhoods developed pre-1950s had a mean Pb concentration of 282 mg kg À1 in their garden soils. Soil HM concentrations should be key criteria when determining the future land use of former residential areas that have been demolished because of the earthquakes in 2010 and 2011. Redeveloping these areas as parklands or forests would result in less human HM exposure than agriculture or community gardens where food is produced and bare soil is exposed.
Soil Research, 2017
Laboratory incubation studies were used to investigate whether and how variability of different p... more Laboratory incubation studies were used to investigate whether and how variability of different plant litters modifies the mobility of nitrogen in soil. Fallen plant foliage from native New Zealand plants of diverse fibre and nutrient content were selected, with C:N ratios ranging from 14 to 102. Different litters provided substantially different inputs of macro- and micronutrients to soil that affected the mobility of N. Both fibre content and C:N ratios were influential. A primary effect of litter addition to soil was modification of pH, largely attributable to calcium enrichment. Nitrate in soil was reduced by up to 85% following litter amendments. Incorporation of five native plant litters into soil significantly suppressed emissions of nitrous oxide. We interpret these findings in the context of plant residues from naturalistic planting on the borders of farm paddocks that may play a role in tightening the N cycle and restricting spillover of nitrogen pollutants to the wider en...
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Papers by Nicholas Dickinson