Collins R.A.,Lincoln University at Christchurch |
Cruickshank R.H.,Lincoln University at Christchurch
Molecular Ecology Resources | Year: 2013
Despite the broad benefits that DNA barcoding can bring to a diverse range of biological disciplines, a number of shortcomings still exist in terms of the experimental design of studies incorporating this approach. One underlying reason for this lies in the confusion that often exists between species discovery and specimen identification, and this is reflected in the way that hypotheses are generated and tested. Although these aims can be associated, they are quite distinct and require different methodological approaches, but their conflation has led to the frequently inappropriate use of commonly used analytical methods such as neighbour-joining trees, bootstrap resampling and fixed distance thresholds. Furthermore, the misidentification of voucher specimens can also have serious implications for end users of reference libraries such as the Barcode of Life Data Systems, and in this regard we advocate increased diligence in the a priori identification of specimens to be used for this purpose. This commentary provides an assessment of seven deficiencies that we identify as common in the DNA barcoding literature, and outline some potential improvements for its adaptation and adoption towards more reliable and accurate outcomes. © 2012 John Wiley & Sons Ltd.
Hulme P.E.,Lincoln University at Christchurch
Journal of Applied Ecology | Year: 2012
Many alien weeds pose significant environmental and/or economic threats across the globe, and methods to assess the potential risk of species introductions are key components in the management of plant invasions. Three broad approaches have been adopted in weed risk assessment: quantitative statistical models, semi-quantitative scoring and qualitative expert assessment. Yet, the effectiveness of these different approaches is rarely evaluated. By bringing together perspectives drawn from statistics, complexity theory, bioeconomics and cognitive psychology, this review presents the first interdisciplinary appraisal of whether weed risk assessment is a valuable tool in the management of plant invasions. Problems in obtaining an objective measure of the hazards posed by weeds, challenges of predicting complex hierarchical and nonlinear systems, difficulties in quantifying uncertainty and variability, as well as cognitive biases in expert judgement, all limit the utility of current risk assessment approaches. The accuracy of weed risk assessment protocols is usually insufficient, given inherent low base-rates even when the costs and benefits of decisions are taken into account, and implies that the predictive value of weed risk assessment is questionable. Current practices could be improved to address consistent hazard identification, encompass a hierarchy of spatio-temporal scales, incorporate uncertainty, generate realistic base-rates, and train risk assessors to limit cognitive biases. However, such refinements may still fail to predict weed risks any better than a knowledge of prior invasion history and quality of climate match. Alternative approaches include scenario planning that seeks qualitative inputs regarding hypothetical events to facilitate long-range planning using multiple alternatives each explicit in their treatment of uncertainty. This represents a change from prevention towards adaptive management where the difficulty in prediction is acknowledged and investment targets early detection, mitigation and management. Synthesis and applications. Scenario planning may be particularly suitable for weeds as they can be rapidly surveyed and have sufficiently long lag phases between naturalisation and invasion that early detection is often feasible. If integrated with assessments of ecosystem vulnerability to invasion and interventions to improve ecosystem resilience, it would deliver a robust post-border approach to invasive plant management. This approach would address threats from new introductions as well as 'sleeper weeds' already present in a region. © 2011 The Author. Journal of Applied Ecology © 2011 British Ecological Society.
Hughey K.F.D.,Lincoln University at Christchurch
Water Resources Management | Year: 2013
In New Zealand and elsewhere no system has existed for objectively ranking the relative importance of different use (e. g., irrigation and hydro electric power) and non-use (e. g., whitewater kayaking, recreational angling, native birdlife) river values. Development of such a system would provide an opportunity for improved policies and rules around water and river use, development and conservation opportunities, and for understanding tradeoffs when competing and overlapping demands are placed on the same resource. In this paper the River Values Assessment System (RiVAS), a Multi Criteria Analysis based approach, is described and demonstrated by application to the salmonid angling value (and in a more limited way to swimming) in Tasman District rivers of the South Island, New Zealand. The system has 10 steps, and a decision support system which finally helps decide the national, regional or local (or high, medium or low) importance or significance of rivers for particular values. As with any MCA approach there is a wide range of limitations all of which are addressed, and none of which are ultimately fatally detrimental to the system. © 2013 Springer Science+Business Media Dordrecht.
Nuthall P.L.,Lincoln University at Christchurch
Agricultural Systems | Year: 2012
Successful grazing management is critical for stock farmers using pasture as the main source of food. Yet many farmers fall a long way short of the output of animal products possible given the pasture production achieved. Farmers have available a number of formal tools to help manage grazing systems, yet few make use of them. Another approach is to develop 'expert systems' encapsulating the skills of the most efficient farmers. This idea is explored based on the information obtained from three successful farmers who were interviewed on a regular basis over several years. The conclusion was that the rules and systems used by one farmer are not likely to apply to another due to their uniqueness. In effect the farmers build up their own personalised intuitive expert system. Thus, a more practical approach is to better train this intuitive skill. A discussion on what constitutes an expert is provided as this leads onto isolating the skills that need improving, and then onto exploring intuition and how it embodies the expert skills. A conclusion on how a farmer's intuition might be improved is offered. Intuition is used by all farmers so the discussion has implications for all farming types. Finally, comments on research into intuition are offered. © 2011 Elsevier Ltd.
Harsch M.A.,Lincoln University at Christchurch |
Bader M.Y.,University of Oldenburg
Global Ecology and Biogeography | Year: 2011
Aim Treelines occur globally within a narrow range of mean growing season temperatures, suggesting that low-temperature growth limitation determines the position of the treeline. However, treelines also exhibit features that indicate that other mechanisms, such as biomass loss not resulting in mortality (dieback) and mortality, determine treeline position and dynamics. Debate regarding the mechanisms controlling treeline position and dynamics may be resolved by identifying the mechanisms controlling prominent treeline spatial patterns (or 'form') such as the spatial structure of the transition from closed forest to the tree limit. Recent treeline studies world-wide have confirmed a close link between form and dynamics. Location The concepts presented refer to alpine treelines globally. Methods In this review, we describe how varying dominance of three general 'first-level' mechanisms (tree performance: growth limitation, seedling mortality and dieback) result in different treeline forms, what 'second-level' mechanisms (stresses, e.g. freezing damage, photoinhibition) may underlie these general mechanisms, and how they are modulated by interactions with neighbours ('third-level' mechanisms). This hierarchy of mechanisms should facilitate discussions about treeline formation and dynamics. Results We distinguish four primary treeline forms: diffuse, abrupt, island and krummholz. Growth limitation is dominant only at the diffuse treeline, which is the form that has most frequently responded as expected to growing-season warming, whereas the other forms are controlled by dieback and seedling mortality and are relatively unresponsive. Main conclusions Treeline form provides a means for explaining the current variability in treeline position and dynamics and for exploring the general mechanisms controlling the responses of treelines to climatic change. Form indicates the relative dependence of tree performance on various aspects of the external climate (especially summer warmth versus winter stressors) and on internal feedbacks, thus allowing inferences on the type as well as strength of climate-change responses. © 2011 Blackwell Publishing Ltd.
Swaffield S.,Lincoln University at Christchurch
Landscape Ecology | Year: 2013
The relationship between science, design, local governance and values is explored using a Christchurch New Zealand case study. Arguments for greater use of design in science are reviewed, and design revealed as fundamentally different from science, being based upon values rather than logic. The role of local governance is examined, and also shown to be value based. This creates tensions with conventional logic based approaches to landscape science. A recently proposed model of design in science is compared with an alternative model that emerges from the recent experience of preparing a wetlands and waterways strategy, in which science is instead engaged with a values based design process. © 2012 Springer Science+Business Media B.V.
Hulme P.E.,Lincoln University at Christchurch
Functional Ecology | Year: 2011
1.The reliability of species distribution models (SDM) to predict the probable response of alien plants to climate change rests on the assumption that plant performance in relation to temperature in the introduced range will be similar to that observed in the native range. Yet, alien plants may exhibit enhanced performance or different environment-distribution relationships following their introduction into a new area. Empirical data are therefore essential to test whether the responsiveness of species to climate is equivalent in the native and introduced ranges. 2.This study tests the assumption that phenological responses of plants to temperature are similar in both their native and introduced range. First flowering date (FFD) is widely used to assess the responsiveness of plants to recent warming arising from global change. For 19 species native to Europe, FFD observed in both the UK and USA between 1970 and 2000 was examined in relation to interannual variation in local temperatures. General trends, variability and responsiveness of FFD to warming were examined for consistency in the contrasting climate of Oxfordshire and Washington DC. 3.Mean FFD in Oxfordshire was a powerful predictor of the same variable in Washington DC, although summer flowering plants in Oxfordshire tended to flower earlier in the season in Washington DC. FFD varied considerably over 30years, but across all species, the range in FFD revealed a similar trend in both regions with larger ranges observed for earlier flowering species. 4.Comparable trends were found between Oxfordshire and Washington DC in the degree to which flowering advanced or regressed per unit temperature increase. In response to warming, the majority of species flowered earlier in both countries and the degree to which FFD responded to increasing temperature was greatest for species flowering earlier in the year. 5.These equivalent phenological responses to temperature across continents imply prediction of the performance of alien plants under climate change may be derived from a species' behaviour in its native range. While these findings support the use of SDM, they also indicate that these models could be significantly improved through the integration of phenological relationships parameterized from data in the native range. © 2011 The Author. Functional Ecology © 2011 British Ecological Society.
Hulme P.E.,Lincoln University at Christchurch
Trends in Ecology and Evolution | Year: 2011
Increasing evidence highlights the role that botanic gardens might have in plant invasions across the globe. Botanic gardens, often in global biodiversity hotspots, have been implicated in the early cultivation and/or introduction of most environmental weeds listed by IUCN as among the worst invasive species worldwide. Furthermore, most of the popular ornamental species in living collections around the globe have records as alien weeds. Voluntary codes of conduct to prevent the dissemination of invasive plants from botanic gardens have had limited uptake, with few risk assessments undertaken of individual living collections. A stronger global networking of botanic gardens to tackle biological invasions involving public outreach, information sharing and capacity building is a priority to prevent the problems of the past occurring in the future. © 2011 Elsevier Ltd.
Hulme P.E.,Lincoln University at Christchurch
New Phytologist | Year: 2011
Plant phenology is particularly sensitive to climate and a key indicator of environmental change. Globally, first flowering dates (FFDs) have advanced by several days per decade in response to recent climate warming, but, while earlier flowering should allow plant distributions to increase, a link between FFD and range changes has not been observed. Here I show for 347 species that the extent to which FFD has responded to climate warming is linked to the degree to which their relative distributions have changed over 30 yr across the British Isles. Native plant species whose phenology did not track climate change declined in distribution, whereas species that became more widespread all exhibited earlier flowering. In contrast, alien neophytes showed both a stronger phenological response to warming and a more marked increase in distribution, but no link between the two. These trends were consistent both for relative changes in the national distribution and for local abundance. At the national scale, the more recently an alien species became established in Britain, the more likely it was to increase in distribution irrespective of FFD, suggesting that recent changes in alien species distributions are decoupled from climate and driven by other factors. © The Author (2010). Journal compilation © New Phytologist Trust (2010).
Wargent J.J.,Massey University |
Jordan B.R.,Lincoln University at Christchurch
New Phytologist | Year: 2013
Largely because of concerns regarding global climate change, there is a burgeoning interest in the application of fundamental scientific knowledge in order to better exploit environmental cues in the achievement of desirable endpoints in crop production. Ultraviolet (UV) radiation is an energetic driver of a diverse range of plant responses and, despite historical concerns regarding the damaging consequences of UV-B radiation for global plant productivity as related to stratospheric ozone depletion, current developments representative of a range of organizational scales suggest that key plant responses to UV-B radiation may be exploitable in the context of a sustainable contribution towards the strengthening of global crop production, including alterations in secondary metabolism, enhanced photoprotection, up-regulation of the antioxidative response and modified resistance to pest and disease attack. Here, we discuss the prospect of this paradigm shift in photobiology, and consider the linkages between fundamental plant biology and crop-level outcomes that can be applied to the plant UV-B response, in addition to the consequences for related biota and many other facets of agro-ecosystem processes. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.