ORCID Profile
0000-0001-8314-0428
Current Organisations
Utrecht University
,
University of Otago
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Publisher: The Royal Society
Date: 30-09-1996
Abstract: Seed mass is correlated with a number of other plant traits, including dispersal mode, growth form and specific leaf area. Specific leaf area is the main determinant of potential relative growth rate and an indicator of the site quality to which a species is adapted. The relationships with dispersal mode and growth form have consistent form in five datasets from three continents, and each account for about 20-30 % of variation in log seed mass. Thus, there is also very substantial variation within growth form and dispersal categories. Much, but not all, of the 20-30% is associated with shifted family composition between growth forms or dispersal modes. Experiments have shown that seedlings of larger-seeded species are better able to survive hazards including deep shade, drought, physical damage and the presence of competing vegetation. If there is a common mechanism under these different hazards, it seemingly must be a ‘reserve effect’, whereby during deployment and early growth larger-seeded species hold a bigger percentage of seed reserves uncommitted to seedling structure and available to support respiration or repair damage. A reserve effect has not yet been demonstrated directly. It remains possible that different mechanisms operate under different hazards. Under a reserve effect, advantages of larger seed size should be temporary, and temporary advantage has indeed been observed with regard to seedling survival under dense shade. Although larger seed mass confers benefits on seedlings, larger seeds must necessarily be produced in smaller numbers per unit of resource allocated. Seed mass is presumed to have evolved as a compromise between these counterposed pressures. Yet there has proved to be surprisingly little difference in average seed mass between very different vegetation regions, at least in temperate climates. Rather, there is startlingly wide variation in seed mass among species growing interspersed with each other. Recent applications of game theory may be capable of accounting for this wide variation between coexisting species, but at present these models are driven by competition among seedling species (as opposed to between seedlings and adults). It remains unclear whether competition among seedlings is a decisive influence on species composition in most of the world’s vegetation types.
Publisher: JSTOR
Date: 06-1995
DOI: 10.2307/2261605
Publisher: Springer Science and Business Media LLC
Date: 23-09-2011
Publisher: Elsevier BV
Date: 07-2006
Publisher: Wiley
Date: 06-11-2017
DOI: 10.1111/AJCO.12785
Abstract: Despite the considerable impact of neuroendocrine tumors (NETs) on patients' lives, the patient journey is not well documented. The aim of this survey was to identify the impact and burden of NETs from the patient perspective. This was a self-reported global survey regarding NET knowledge/awareness, disease impact/management, interaction with medical teams, and desired improvements. One hundred thirty-eight patients (7% of the global study) in the Oceania region answered closed-ended questions using graded descriptors on their experience of living with NETs. The personal lives of patients were negatively impacted by NETs, including overall energy levels (72%, 99/138), emotional health (66%, 91/138), and finances (56%, 77/138). Eighty-one percent (22/27) of patients not currently working stated that their NET was the reason they were not employed. Of those still working, taking days off work (64%, 39/61), working reduced hours (44%, 27/61) and stopping work for a period of time (31%, 19/61) were the most frequently reported outcomes of having a NET. Although most patients felt supported by their medical team (53% [73/138] reported being extremely or very supported by healthcare professionals in general), patients also identified areas for improvement in patient care. Better access to NET-specific treatments (58%, 80/138), more awareness about NETs (58%, 80/138) and materials to help patients better explain their condition (52%, 72/138) were indicated by patients as ways to help them live better with their disease. The survey demonstrated a considerable burden of NETs on patients' lives and identified areas for improvements in long-term management.
Publisher: New Zealand Ecological Society
Date: 31-01-2022
Publisher: Springer Science and Business Media LLC
Date: 09-2006
DOI: 10.1007/S00442-006-0523-Z
Abstract: Accessory costs of reproduction are those that are necessary to mature a seed, but that do not involve the direct cost of provisioning the seed itself. This study aims to quantify accessory costs in a range of species, and test whether they decrease as a proportion of total reproductive expenditure with increasing seed mass, as might be expected if economies of scale came into play at larger seed sizes. We also test whether accessory costs varied with growth form, pollination mode, and dispersal mode, with the expectation that biotic pollination and dispersal modes should incur greater costs. Reproductive allocation (dry biomass) over one season, was calculated for 14 diclinous angiosperm species. Accessory costs averaged 73% of total reproductive allocation, with the majority spent on packaging and dispersal. Total accessory costs, packaging and dispersal costs, and costs incurred prior to pollination were proportional to direct costs of reproduction in major axis regressions. However, larger seeded species incurred significantly greater costs associated with aborted seeds and fruits, and matured a smaller proportion of ovules. This is consistent with larger seeded species being more selective of the ovules/embryos matured than small-seeded species. Total accessory costs, and proportion of ovules aborted, were also significantly greater for biotically dispersed species, but only due to an association with larger seed masses. Costs associated with abortions were lower for biotically pollinated species, due to a general trend of more ovules per ovary, resulting in greater cost sharing. This study demonstrates that expenditure on items other than seeds accounts for the majority of reproductive allocation in flowering plants. Yet, far more literature exists on seed mass variation than on investment in accessory structures. We found a proportional relationship between accessory costs and seed mass that warrants further investigation within the context of selection on margin returns on investment.
Publisher: Wiley
Date: 1997
Publisher: Norwegian Polar Institute
Date: 2016
Publisher: Center for Open Science
Date: 05-08-2022
Publisher: Informa UK Limited
Date: 11-2015
DOI: 10.1657/AAAR0014-098
Publisher: Wiley
Date: 30-11-2022
Abstract: Tree seedling establishment outside forest boundaries is controlled by many interacting factors. Understanding the relative importance of different pressures is essential for improving techniques for forest restoration and for understanding the potential of forest boundaries to shift and adapt to changing climate conditions. We investigated constraints on the spread of a key southern hemisphere forest type into grasslands by undertaking a multifactorial experiment sowing Nothofagus cliffortioides (Nothofagaceae) in a historically deforested retired pasture. We manipulated factors to determine the relative effects of sheltered microsites, competition with pasture species, availability of ectomycorrhizal fungi, soil nutrients and rabbit herbivory, on seedling emergence and survival. Overall survival was low (11.7% after 6 months and 1.5% after 10 months), but there were strong treatment effects on both seedling establishment and survival. The availability of shelter and competition with pasture species had strongest effects, with the presence of pasture species initially aiding seedling emergence due to a sheltering effect, but negatively affecting survival at later stages. Most remaining seedlings at the conclusion of the experiment had formed ectomycorrhizae regardless of whether inoculum was supplied, and seedling survival and health was positively related to ectomycorrhizal colonization. Fertilizing had less of an effect than other factors, and results regarding rabbit herbivory were inconclusive. Synthesis and applications . This study provides new insights into how factors interact to limit tree seedling establishment in grasslands and forest expansion into neighbouring ecosystems. This improves understanding of the ability of an ectomycorrhizal keystone forest species to migrate and adapt to climate change. This study also assists restoration practitioners in selecting techniques that will enhance seedling establishment, and highlights that direct seeding approaches in open grasslands are unlikely to result in high rates of Nothofagus establishment.
Publisher: Informa UK Limited
Date: 11-01-2023
Publisher: Wiley
Date: 18-04-2012
Publisher: Wiley
Date: 07-04-2015
DOI: 10.1111/AEC.12238
Publisher: Oxford University Press (OUP)
Date: 28-02-2017
Publisher: Wiley
Date: 29-08-2012
DOI: 10.1111/J.1558-5646.2011.01425.X
Abstract: Accessory costs of reproduction frequently equal or exceed direct investment in offspring, and can limit the evolution of small offspring sizes. Early angiosperms had minimum seed sizes, an order of magnitude smaller than their contemporaries. It has been proposed that changes to reproductive features at the base of the angiosperm clade reduced accessory costs thus removing the fitness disadvantage of small seeds. We measured accessory costs of reproduction in 25 extant gymnosperms and angiosperms, to test whether angiosperms can produce small seeds more economically than gymnosperms. Total accessory costs scaled isometrically to seed mass for angiosperms but less than isometrically for gymnosperms, so that smaller seeds were proportionally more expensive for gymnosperms to produce. In particular, costs of abortions and packaging structures were significantly higher in gymnosperms. Also, the relationship between seed:ovule ratio and seed size was negative in angiosperms but positive in gymnosperms. We argue that the carpel was a key evolutionary innovation reducing accessory costs in angiosperms by allowing sporophytic control of pre- and postzygotic mate selection and timing of resource allocation. The resulting reduction in costs of aborting unfertilized ovules or genetically inferior embryos would have lowered total reproductive costs enabling early angiosperms to evolve small seed sizes and short generation times.
Publisher: Springer Science and Business Media LLC
Date: 02-07-2015
Publisher: Frontiers Media SA
Date: 2012
Publisher: University of Chicago Press
Date: 09-1995
DOI: 10.1086/285804
Publisher: Cold Spring Harbor Laboratory
Date: 08-04-2022
DOI: 10.1101/2022.04.06.487384
Abstract: 1. Understanding what drives community assembly processes and how communities respond to environmental gradients are fundamental goals in community ecology. Ectomycorrhizal fungi support major forest systems across the globe, but the ersity, distribution and environmental controls affecting ectomycorrhizal community composition are unknown in many regions, particularly in the southern hemisphere. Here we investigate the assembly of ectomycorrhizal fungal communities based on eDNA s les from 81 Nothofagus forests across New Zealand’s South Island. We apply zeta ersity analysis and multi-site generalised dissimilarity modelling (MS-GDM) to investigate assembly patterns and quantify the effects of 43 biotic and environmental variables on community turnover. The zeta ersity MS-GDM framework differentiates between the environmental factors driving turnover of rare and common species, so provides a more complete picture of community dynamics than traditional beta ersity analyses. Results showed that community assembly was dominated by deterministic rather than stochastic processes. Soil variables were important drivers across the full range of rare, intermediate and common species. Ground cover variables, forest patch size and rainfall had greater effects on turnover of rare species, whereas temperature variables and host tree size had greater effects on common species turnover. Applying these methods for the first time to fungi demonstrates that there are distinct differences in the ecological processes affecting different aspects of the ectomycorrhizal community, which has important implications for understanding the functional effects of community responses to environmental change.
Publisher: Wiley
Date: 29-03-2007
Publisher: Wiley
Date: 02-02-2023
DOI: 10.1111/MEC.16860
Abstract: A fundamental goal in community ecology is to understand what factors drive community assembly processes. The factors affecting ectomycorrhizal fungal communities are unknown in many regions, particularly in the southern hemisphere. We investigate community assembly using ITS2 metabarcoding of ectomycorrhizal fungi s led from 3943 hyphal ingrowth bags buried in 81 Nothofagus forests across New Zealand's South Island. By applying zeta ersity analysis and multisite generalized dissimilarity modelling (MS‐GDM) we quantify the effects of 43 biotic and environmental variables on community turnover. Unlike traditional beta ersity analyses that are heavily influenced by rare species, the zeta ersity framework differentiates between factors driving turnover of rare and common species, providing a more complete picture of community dynamics. We found that community assembly was dominated by deterministic rather than stochastic processes and identified ecological factors affecting all taxa, as well as others that were specifically important to rare or common taxa. Soil variables were important drivers of turnover for all species, whereas ground cover variables, forest patch size, precipitation and host tree identity had greater effects on rarer species, and tree size and temperature effects were specific to more common species. Interestingly, the effect of temperature on common species is in line with recent evidence from other Kingdoms, pointing to possible generality, and highlighting the importance of considering common species. Applying these methods to fungi has allowed us to identify the distinct ecological processes that structure rare and common taxa during community assembly. This has important implications for understanding the functional effects of community responses to environmental change.
Publisher: Society for Neuroscience
Date: 29-08-2012
DOI: 10.1523/JNEUROSCI.1088-12.2012
Abstract: Why are some in iduals more susceptible to the formation of inflexible habits than others? In the present study, we used diffusion tensor imaging to demonstrate that brain connectivity predicts in idual differences in relative goal-directed and habitual behavioral control in humans. Specifically, vulnerability to habitual “slips of action” toward no-longer-rewarding outcomes was predicted by estimated white matter tract strength in the premotor cortex seeded from the posterior putamen (as well as by gray matter density in the posterior putamen as determined with voxel-based morphometry). In contrast, flexible goal-directed action was predicted by estimated tract strength in the ventromedial prefrontal cortex seeded from the caudate. These findings suggest that integrity of dissociable corticostriatal pathways underlies in idual differences in action control in the healthy population, which may ultimately mediate vulnerability to impulse control disorders.
Publisher: Wiley
Date: 03-2021
DOI: 10.1111/REC.13333
Abstract: Nothofagus (southern beech) species form a major component of southern hemisphere forests, and in many regions are becoming an important focus for restoration efforts. However, restoration projects are predominantly carried out at small, local scales using a wide range of different techniques that have produced mixed results. In order to improve outcomes and develop general strategies for southern beech restoration, we review and compare data from previous trials to determine what techniques have been scientifically tested, identify the most effective methods, and pinpoint gaps in current practices. We assessed the effects of restoration techniques, applied in 91 trials from 22 publications across the southern hemisphere, on seedling survival and growth. Providing shelter improved both seedling survival and growth, controlling weeds improved survival, and protecting from herbivores improved seedling growth. Despite being one of the most commonly applied techniques, fertilizer application only marginally improved seedling survival and did not significantly influence seedling growth. Other techniques, such as increasing glasshouse container size or growth time or manipulating soil before planting, showed mixed results. Surprisingly, no trials examined the use of ectomycorrhizal fungal inoculum as a restoration technique. We discuss the outcomes of this review in the context of our current understanding of southern beech regeneration ecology, to inform future Nothofagus restoration practices and suggest where future research should be directed.
Publisher: Cambridge University Press (CUP)
Date: 05-2013
DOI: 10.1017/S0024282913000017
Abstract: Thamnolia vermicularis is a globally widespread arctic-alpine lichen with two distinct chemotypes. The intermixing of these chemotypes at the local scale and lack of genetic variation between them is puzzling given the apparent absence of specialized reproductive structures. Apothecia and conidiomata were originally reported for Thamnolia in the second half of the 19th century, but putative apothecia proved to be parasitic in origin. This study presents conclusive microscopic evidence for the existence of pycnidial conidiomata containing conidia on thalli of Thamnolia vermicularis from geographically widespread locations. Sequences of the internal transcribed spacer (ITS) region of ribosomal DNA from excised pycnidial conidiomata matched that of thallus tips from in idual Thamnolia thalli. Our examination of the historic literature found that the occurrence of pycnidial conidiomata was never disproved, but this information was lost from the post-1920s English-language literature. Our rediscovery of pycnidial conidiomata indicates that Thamnolia vermicularis possesses a reproductive strategy with the potential for long-distance dispersal of multitudes of mitotically produced conidia, providing a plausible explanation for the cosmopolitan distribution of the species and the low levels of genetic variation among populations. Reversible processes, for ex le alternative splicing, warrant consideration as explanations for chemotype intermixing.
Publisher: Cold Spring Harbor Laboratory
Date: 07-01-2021
DOI: 10.1101/2021.01.04.425314
Abstract: We introduce the AusTraits database - a compilation of measurements of plant traits for taxa in the Australian flora (hereafter AusTraits). AusTraits synthesises data on 375 traits across 29230 taxa from field c aigns, published literature, taxonomic monographs, and in idual taxa descriptions. Traits vary in scope from physiological measures of performance (e.g. photosynthetic gas exchange, water-use efficiency) to morphological parameters (e.g. leaf area, seed mass, plant height) which link to aspects of ecological variation. AusTraits contains curated and harmonised in idual-, species- and genus-level observations coupled to, where available, contextual information on site properties. This data descriptor provides information on version 2.1.0 of AusTraits which contains data for 937243 trait-by-taxa combinations. We envision AusTraits as an ongoing collaborative initiative for easily archiving and sharing trait data to increase our collective understanding of the Australian flora.
Publisher: Wiley
Date: 03-2023
DOI: 10.1111/NPH.18802
Abstract: Mechanisms of ersification in fungi are relatively poorly known. Many ectomycorrhizal symbionts show preference for particular host genera or families, so host–symbiont selection may be an important driver of fungal ersification in ectomycorrhizal systems. However, whether ectomycorrhizal hosts and symbionts show correlated evolutionary patterns remains untested, and it is unknown whether fungal specialisation also occurs in systems dominated by hosts from the same genus. We use metabarcoding of ectomycorrhizal fungi collected with hyphal ingrowth bags from Nothofagus forests across southern New Zealand to investigate host–symbiont specialisation and correlated evolution. We examine how ectomycorrhizal communities differ between host species and look for patterns of host–symbiont cophylogeny. We found substantial differences in ectomycorrhizal communities associated with different host taxa, particularly between hosts from different subgenera ( Lophozonia and Fuscospora ), but also between more closely related hosts. Twenty‐four per cent of fungal taxa tested showed affiliations to particular hosts, and tests for cophylogeny revealed significant correlations between host relatedness and the fungal phylogeny that extended to substantial evolutionary depth. These results provide new evidence of correlated evolution in ectomycorrhizal systems, indicating that preferences among closely related host species may represent an important evolutionary driver for local lineage ersification in ectomycorrhizal fungi.
Publisher: JSTOR
Date: 08-1995
DOI: 10.2307/2261640
Publisher: Wiley
Date: 20-04-2010
Publisher: Wiley
Date: 23-07-2018
DOI: 10.1111/AEC.12643
Publisher: Informa UK Limited
Date: 11-01-2021
Publisher: Magnolia Press
Date: 13-05-2020
DOI: 10.11646/PHYTOTAXA.442.4.1
Abstract: This study reports, based on molecular phylogenetic analyses and a morphological assessment, the second species of Pacifigeron, an endemic genus of Rapa Island in French Polynesia. Detailed morphological and ecological descriptions, illustrations, IUCN Red List assessment, and a distributional map are provided. Our results support the exclusion of Pacifigeron from the Celmisia group and also allow the re-circumscription of the Celmisia group. The new species Pacifigeron in isus can be differentiated from P. rapensis, among other characters, by its larger leaves, larger number of capitula per capitulescence, corollas lacking long uniseriate multicellular trichomes, style of the disc florets un ided, and absence of twin trichomes on the cypsela epidermis. Molecular data indicates that Pacifigeron is related to South American Andean genera rather than to the Celmisia group as was previously proposed. The Celmisia group is here re-circumscribed to include ca. 159 species distributed in Australasia within the following genera: Celmisia, Damnamenia, Olearia pro parte, Pachystegia, and Pleurophyllum. Given the taxonomic complexity and polyphyletic nature of Olearia, its taxonomy is briefly reviewed based on history, morphology, and phylogenetic evidence, which in turn allows delineation of its species composition within the Celmisia group. None of the Olearia species in the Celmisia group can be retained in Olearia since the type species, O. tomentosa, does not belong to the Celmisia group.
Publisher: Springer Science and Business Media LLC
Date: 23-04-2005
DOI: 10.1007/S00442-005-0087-3
Abstract: If snow cover in alpine environments were reduced through climatic warming, plants that are normally protected by snow-lie in winter would become exposed to greater extremes of temperature and solar radiation. We examined the annual course of frost resistance of species of native alpine plants from southern New Zealand that are normally buried in snowbanks over winter (Celmisia haastii and Celmisia prorepens) or in sheltered areas that may accumulate snow (Hebe odora) and other species, typical of more exposed areas, that are relatively snow-free (Celmisia viscosa, Poa colensoi, Dracophyllum muscoides). The frost resistance of these principal species was in accord with habitat: those from snowbanks or sheltered areas showed the least frost resistance, whereas species from exposed areas had greater frost resistance throughout the year. P. colensoi had the greatest frost resistance (-32.5 degrees C). All the principal species showed a rapid increase in frost resistance from summer to early winter (February-June) and maximum frost resistance in winter (July-August). The loss of resistance in late winter to early summer (August-December) was most rapid in P. colensoi and D. muscoides. Seasonal frost resistance of the principal species was more strongly related to daylength than to temperature, although all species except C. viscosa were significantly related to temperature when the influence of daylength was accounted for. Measurements of chlorophyll fluorescence indicated that photosynthetic efficiency of the principal species declined with increasing daylength. Levels of frost resistance of the six principal alpine plant species, and others measured during the growing season, were similar to those measured in tropical alpine areas and somewhat more resistant than those recorded in alpine areas of Europe. The potential for frost damage was greatest in spring. The current relationship of frost resistance with daylength is sufficient to prevent damage at any time of year. While warmer temperatures might lower frost resistance, they would also reduce the incidence of frosts, and the incidence of frost damage is unlikely to be altered. The relationship of frost resistance with daylength and temperature potentially provides a means of predicting the responses of alpine plants in response to global warming.
No related grants have been discovered for Janice Lord.