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Integrative analysis of stressor gradients reveals multiple discrete trait‐defined axes underlie community assembly
Get PDFThe generalizable functional attributes of organisms (traits) relate strongly to their environment across multiple levels of biological organization, making trait-based approaches a powerful mechanistic framework to understand species distributions and community composition in relation to environmental change. To investigate how a wide range of stressor types shape stream macroinvertebrate communities, we conducted an integrative analysis using community and taxon trait information across drying, flooding, eutrophication, fine sediment, and acid mine drainage (AMD) gradients. Each gradient spanned relatively unimpacted to severely impacted sites. To characterize community change in response to stressors, we incorporated abundance-based trait information from all stressor gradients in a single trait-based ordination (nonmetric multidimensional scaling), defining the trait space within which each stressor gradient acted. We hypothesized that different stressors would apply different environmental filters, moving communities along distinct axes in trait space and resulting in communities with definable trait combinations. Particularly strong relationships were associated with anthropogenically derived stressors (fine sediment, eutrophication, and AMD) compared to natural stressors (drying and flooding). Anthropogenic stressors instigated significant movement of communities along multiple axes in trait space, likely driven by limited adaptation to these novel stressors. We demonstrate that trait-based analysis of communities across multiple stressor gradients can support a more comprehensive understanding of how community composition changes than taxonomic methods or investigation of a single stressor type, and could underpin community-focused management actions
A preliminary investigation of myostatin gene (MSTN) variation in red deer (Cervus elaphus) and its implications for venison production in New Zealand
Get PDFMyostatin (MSTN), also known as growth differentiation factor 8 (GDF-8), is a negative regulator of lean muscle tissue growth. Variation in the gene has been studied in many domesticated species, because of its potential to dramatically increase muscle mass. It has, however, not been investigated in red deer (Cervus elaphus). In this study, variation in MSTN intron 1 was investigated in 211 male New Zealand red deer, for which phenotypic measurements of M. Longissimus dorsi (eye muscle) (width, depth, and area, together with 12-month weight) were recorded. Two sequence variants (named A and B) differing by one nucleotide (c.373 + 224) were identified in the intron 1 region of the gene resulting in three genotypes (AA, AB, and BB; frequencies of 63.5%, 30.8%, and 5.7%, respectively), but no association between this variation and any of the quantitative measurements was detected. These results suggest that the deer MSTN is less variable than for other livestock species and that its activity may be controlled to maintain a size–growth equilibrium
COVID-19 and the Locavores: Investigating the drivers of US consumer preferences for apples
Get PDFThis study provides insights and best-practice recommendations for marketing managers in the US food retail sector and the horticultural industry. An online survey distributed via a crowd sourcing platform in 2021 aimed to explore the factors that explained the intentions of US consumers to purchase locally grown apples. The Theory of Planned Behavior was used as a conceptual framework to shape the proposed model. The results emphasize the importance of behavioral, normative and control beliefs as important factors towards attitudes. Subjective norms and perceived behavioral control were also found to be key drivers in understanding behavioral intention. All concepts, with the exception of perceived behavioral control, were found to be significant behavioral predictors
Grassland plant and invertebrate species richness increases from mowing are mediated by impacts on soil chemistry
Get PDFPasture and improved grasslands are commonly managed by a combination of artificial fertilisation and biomass removal, but a deeper understanding of how management options interact over the long-term are required to improve sustainability. Studies of multi-trophic responses to these options can provide important insights for biodiversity and soil management, particularly when they cover long time periods. In this study, we provide a novel perspective on long-term experimental field studies of grassland management by examining the direct and indirect effects of N fertilisation and mowing (with biomass retention and removal) on above-ground biodiversity, below-ground soil chemistry and their interactions. Our experimental treatments were applied annually from 1994 in medium to high soil fertility conditions on a non-native pastoral farm in New Zealand, and analysis of data to 2013 show that in general, plants and soil properties did not respond to N fertiliser treatments. In response to mowing regimes, soil properties exhibited subtle, but annually varying changes mostly related to biomass retention or removal, and plant richness was consistently higher under all mowing treatments. The management regime with the greatest gains in diversity also depended on year of study. We further analysed the indirect effects of mowing treatments on plant and arthropod richness via soil properties using structural equation modelling, and found that the impact of mowing is likely to be mediated by soil chemistry changes. In particular, the direct positive impact of mowing on plant richness may be offset by changes to soil properties, depending on whether biomass is retained or removed. We suggest that management regime effects on soil chemistry may limit plant composition changes to those species able to take advantage of altered conditions. These findings suggest that management to improve grassland diversity and soil conditions should consider the abiotic history and conditions of the site
You are what you eat: Fungal metabolites and host plant affect the susceptibility of diamondback moth to entomopathogenic fungi
Get PDFBackground: Beauveria are entomopathogenic fungi of a broad range of arthropod pests. Many strains of Beauveria have been developed and marketed as biopesticides. Beauveria species are well-suited as the active ingredient within biopesticides because of their ease of mass production, ability to kill a wide range of pest species, consistency in different conditions, and safety with respect to human health. However, the efficacy of these biopesticides can be variable under field conditions. Two under-researched areas, which may limit the deployment of Beauveria-based biopesticides, are the type and amount of insecticidal compounds produced by these fungi and the influence of diet on the susceptibility of specific insect pests to these entomopathogens.
Methods: To understand and remedy this weakness, we investigated the effect of insect diet and Beauveria-derived toxins on the susceptibility of diamondback moth larvae to Beauveria infection. Two New Zealand-derived fungal isolates, B. pseudobassiana I12 Damo and B. bassiana CTL20, previously identified with high virulence towards diamondback moth larvae, were selected for this study. Larvae of diamondback moth were fed on four different plant diets, based on different types of Brassicaceae, namely broccoli, cabbage, cauliflower, and radish, before their susceptibility to the two isolates of Beauveria was assessed. A second experiment assessed secondary metabolites produced from three genetically diverse isolates of Beauveria for their virulence towards diamondback moth larvae.
Results: Diamondback moth larvae fed on broccoli were more susceptible to infection by B. pseudobassiana while larvae fed on radish were more susceptible to infection by B. bassiana. Furthermore, the supernatant from an isolate of B. pseudobassiana resulted in 55% and 65% mortality for half and full-strength culture filtrates, respectively, while the filtrates from two other Beauveria isolates, including a B. bassiana isolate, killed less than 50% of larvae. This study demonstrated different levels of susceptibility of the insects raised on different plant diets and the potential use of metabolites produced by Beauveria isolates in addition to their conidia
Preadaptation, hybridisation, and breeding system shape the invasion of three Rumex species in New Zealand : A thesis submitted in partial fulfilment of the requirements for the Degree of Doctor of Philosophy at Lincoln University
Get PDFResearch has previously shown that Rumex (Polygonaceae) species introduced to New Zealand have multiple potential drivers behind their success, such as phenotypic plasticity, enemy release, and niche shift. However, it is not known whether these changes were caused by post-introduction evolution, or what other drivers could explain the success of these agricultural weeds. I combined demo-genetic traits and processes to assess how hybridisation and introgression, genetic differentiation, and breeding system contribute to the invasiveness of three introduced Rumex species. I compared plants from the species’ native (Europe, mainly the UK) and introduced (New Zealand) range and assessed whether the success is more likely due to prior adaptation or post-introduction evolution.
Ploidy is associated with increased invasiveness, and if a species has multiple geo-cytotypes, higher ploidies are often found within the introduced range. Similarly, self-compatibility can help introduced populations to counter mate limitation and mixed mating can introduce new alleles to populations. I found no differences in genome sizes or chromosome numbers between plants from the two ranges using flow cytometry and manual chromosome counts. In addition, a comparison between bagged and unbagged Rumex conglomeratus plants showed no consequences from selfing, indicating mixed mating strategies. Surprisingly, the overall seed viability was lower for provenances from the introduced range compared to the native range. Hybridisation and introgression can increase genetic variation and help with adaptation to new environments. In a field survey, hybrid plants were found in New Zealand. However, the majority were likely first-generation hybrids, making introgression an unlikely driver behind the invasiveness. In addition, the parent species co-occurrence was lower in New Zealand compared to the UK. Lastly, genetic differentiation can indicate the origin of the introduction, as well as how likely a post-introduction evolution is a driver behind the invasiveness. A minimal differentiation was revealed by genotyping-by-sequencing both within but also between the native and introduced ranges. The population genetic analyses suggest that the UK is a likely origin for these species but admixture from elsewhere was also found. This would have likely helped the introduced populations to maintain comparable level of genetic variation to the native populations.
As limited differences were found between the native and introduced populations, the investigated traits and processes are unlikely to explain the invasiveness in New Zealand. Rather, the success of these species is likely caused by prior adaptation. In addition, as these species are primarily agricultural weeds within both provenances, anthropogenically induced adaptation to invade is likely the main driver behind the success of these species. This method of adaptation, likely coupled with jack-of-all-trades genotypes, have allowed the species to thrive in manmade habitats, all around the globe. Thus, similar weeds within these habitats need to be carefully monitored to prevent further invasions in the future
Characterisation of tannin and aroma profiles of Pinot noir wines made with or without grape pomace
Get PDFThe contribution of grape pomace on tannin concentration, tannin composition and aroma profile of Pinot noir wine was studied using different fermentation media to make up four treatments: GJ-P, grape juice plus pomace; MJ-P, model juice plus pomace; GJ, grape juice; MJ, model juice. The MJ-P treatment showed significantly lower amounts of tannins, mean degree of polymerisation (mDP), similar amounts of anthocyanin, and a similar secondary aroma profile compared to the GJ-P treatment. Grape pomace addition significantly increased the tannin concentration in wines. This study was also revealed the importance of phenolics present in grape juice in tannin polymerisation and final tannin concentration in wines. Grape pomace addition significantly reduced some important aroma compounds such as acetate esters (except ethyl acetate), most of the volatile fatty acids, a few ethyl esters and β-damascenone but increased some primary aromas in wines due to the presence of their aroma precursors in skins. Hence, these results indicate that grape pomace may bind or delay the release of some aroma compounds and/or lose these compounds during cap management in GJ-P and MJ-P treatments compared to the respective juice treatments
Shifting discourses of nature in participatory processes for environmental management
No full textThe increasing use of participatory processes in environmental governance and management has implications for the way different conceptualisations of nature and the environment are recognised within environmental decision-making. This article draws on a case study of the Ōngātoro Maketū estuary restoration initiative in Aotearoa, New Zealand, to examine how shifting discourses of nature and the environment intersect with the exercise of power to influence decision-making on the estuary. The study is based on a qualitative analysis of an archive of historical policy and planning documents, and 25 in-depth interviews with participants involved in the restoration initiative. The analysis demonstrates that despite a participatory process that often reinforced the dominant cultural paradigm and power relations, it created the space for different knowledge forms including western science and Māori knowledge to help improve the quality of decisions. We argue that well-designed participatory processes have much potential to address the growing complexity and uncertainty underpinning environmental governance and management
Energy prices and the macroeconomy: New evidence from Hodrick–Prescott and Hamilton filters
No full textPurpose: This paper aims to investigate the cyclical associations among energy prices and key macroeconomic variables for the USA.
Design/methodology/approach: To this end, the recently developed Hamilton filter (HF) and the oft-used Hodrick–Prescott filter (HPF) are used. The two methods produce starkly different results regarding the relationships between energy prices on the one hand and output and employment on the other. Findings: While the HF suggests that energy prices are acyclical, the HPF suggests they are procyclical. However, the associations between energy prices and inflation are robust across the two methods, indicating that energy prices are strongly correlated with – and lead – the consumer price index (CPI). Furthermore, unlike the results produced by the HPF, those produced by the HF are robust across seasonally adjusted and unadjusted data.
Research limitations/implications: Given the inherent seasonality in energy prices and the differences in the underlying processes that generate macroeconomic and energy prices, the results obtained from the HPF filter should be interpreted with caution.
Originality/value: To the best of the authors’ knowledge, this is the first study that uses the recently developed HF to examine the associations between the cyclical behaviors of three key macroeconomic variables in the USA – the industrial production index, the CPI, and total nonfarm employment – and the prices of natural gas, crude oil, gasoline, diesel, and heating oil. Second, this study presents a comparison of the results produced by the two filtering techniques. Third, recognizing that energy prices are characterized by seasonality, this study tests the robustness of the results produced by the two filters across seasonally adjusted and unadjusted data
Socio-ecological resilience by design for flood-prone waterfront cities: A comparative study of New Orleans, USA; Brisbane, Australia and Christchurch, New Zealand
No full textWith climate change having increasing impacts on our cities and regions, the need for long-term and sustainable solutions is critical. Natural hazards are increasing in occurrence and intensity, and cities are proposing plans to increase their capacities to resist and withstand these occurrences. Resilience of cities to environmental hazards is often dominated by a worldview of ‘a system in equilibrium’, but this negates the wide diversity of social and ecological systems responding to change around the world. Three cities are used in this chapter as case studies to show how each have similarities in flood and disaster-prone physical landscapes and human influences. New Orleans (United States), Brisbane (Australia) and Christchurch (New Zealand) have had similar colonial-influenced histories, have managed water as both an asset and a liability, and have begun city planning for improved socio-ecological resilience. The case studies illustrate barriers and enablers that are context-specific and require landscape architectural design solutions to contribute to more robust and resilient cities in the face of likely hazards in their part of the world. The three selected cities have numerous experiences specific to their own unique circumstances that are related in this chapter to socio-environmental drivers that enhance their adaptive capacity. By comparing cities with similar histories but divergent experiences specific to their own geomorphological and meteorological hazards, we suggest that cities must find what is appropriate for their particular socio-ecological contexts through resilience by design