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Brushtail possum (Trichosurus vulpecula) movement and removal success in the sea-cliff eco-systems of Banks Peninsula
No full textBrushtail possums (Trichosurus vulpecula) are well-recognized for their ability to inflict widespread damage on much of Aotearoa New Zealand's native flora and fauna, putting them firmly on the list of invasive species to be targeted for removal. However, there is little understanding of how the vegetative and topographical features of sea-cliff eco-systems influence their movements, and the subsequent impacts on control operations. With the instigation of the Predator Free New Zealand 2050 program, this becomes key information for each type of eco-system to achieve total and complete eradication nationwide. This project focuses on the influence of habitat in this particular environment, how this impacts possum movements and home-ranges in comparison to current understanding in other types of eco-systems such as dryland pasture or forest eco-systems. Alongside Pest Free Banks Peninsula, attention was turned to how best to eradicate this invasive pest species in a landscape that provides significant topographical challenges. GPS tracking collars will be used to evaluate possum movement and habitat use, then uniquely marked mortality collars and cameras will determine the success of a ground-based bait station operation in removing this population. Encounter-interaction rates, bait take, how these both change over time, as well as estimated population removal percentage will all be used to help determine operational success. We predict that the project results will be able to inform organizations such as Pest Free Banks Peninsula whether ground-base bait station operations will provide the outcomes they require, and to identify areas that would benefit from further investigation
Bryophyte community composition is influenced by microhabitat and cover of vascular plants and lichens in New Zealand montane forest
Get PDFBryophytes are important to terrestrial ecosystems, as they build soil and improve habitats for vascular plants. We investigated the influence of substrate pH, light, and cover of lichens and vascular plants on bryophyte communities in different microhabitats near the Lewis Pass. The effect of tree diameter and trunk aspect on epiphytic communities was also examined. In total, 30 bryophyte species were identified in 98 0.25 m² quadrats in five forest microhabitats (kānuka/mānuka and beech forest floor, beech tree trunks, and streamside and decomposing wood in beech forest). Bryophyte community composition in streamside microhabitats differed from all other microhabitats. Bryophyte community composition on the beech forest floor differed from the community on kānuka/mānuka forest floor; these differences were correlated with vascular plant and lichen cover. The composition and cover of epiphytic communities on tree trunks were correlated with aspect and lichen cover, there was no effect of tree diameter. No effect of substrate pH was found, although pH only ranged from 4 to 6. This study is one of the first in New Zealand to study the relationship between environmental factors and bryophyte communities in beech and kānuka/mānuka forests, contributing to our understanding of these understudied, key components of New Zealand forest ecosystems
Dynamic connectedness among the implied volatilities of oil prices and financial assets: New evidence of the COVID-19 pandemic
No full textThis paper examines the dynamic connectedness among the implied volatilities of oil prices (OVX) and fourteen other assets, which can be grouped into five different assets classes (i.e., energy commodities, stock markets, precious metals, exchange rates and bond markets). To do so we estimate a recently developed time-varying parameter vector autoregressive (TVP-VAR) connectedness approach using daily data spanning from March 16th, 2011 to March 3rd, 2021 — covering the first year of the COVID-19 pandemic. The empirical results suggest that connectedness across the different asset classes and oil price implied volatilities are varying over time and fluctuate at very high levels. The dynamic total connectedness ranges between 65% and 85% indicating a high degree of cross-market risk linkages. Furthermore, we find that the oil market is becoming more integrated with the financial markets, since it tends to be materially impacted by abrupt fluctuations of the global financial markets’ volatilities. More specifically, the analysis shows that, throughout the period, OVX is a net receiver of shocks to the remaining implied volatilities. Finally, the net pairwise connectedness measures suggest that OVX is constantly at the net receiving end vis-a-vis the majority of the asset classes’ implied volatilities. Those findings are of major importance for portfolio and risk management in terms of asset allocation and diversification
Detection of fish and mussel DNA in lake sediment cores depends on location, species, and molecular method
No full textEnvironmental DNA provides an opportunity to track long‐term changes in biological communities in lake ecosystems but the detection of macroorganisms, such as freshwater fish and mussels, in sedimentary DNA (sedDNA) has only been successfully reported in a few studies to date. Factors such as low abundance of the target organisms, sampling location, the molecular approach used, and DNA quantity may influence detection, though studies exploring these factors are lacking. In the present study, sediment cores were collected from a depocenter and nearshore site in a small shallow lake where some historical fish survey data was available. DNA was extracted from the sediment core and analyzed for Anguilla australis (shortfin eel), Echyridella menziesii (freshwater mussel), and Perca fluviatilis (European perch) using droplet digital PCR (ddPCR) and general fish (class Actinopterygii) and macroinvertebrates using metabarcoding. The data from the historical fish surveys (last 20 years) aligned with the molecular data except for a lack of Anguilla dieffenbachii (longfin eel) DNA detection. Generalized additive mixed model analysis showed significantly higher detections in samples from the nearshore compared to depocenter core, which is most likely related to habitat of the target species. Differential detection of target species was likely caused by their ecology and locality. The ddPCR assays were more sensitive (88 ± 3% of samples with positive detections) than metabarcoding (48 ± 10%). However, the metabarcoding enabled the detection of additional fish species. Target species detection was negatively impacted by a reduction in total DNA concentration in older sediments. This research highlights that current molecular techniques used to target fish and mussel sedDNA can result in inconsistent temporal and spatial detection of species, especially in older sediments. We recommend that the methodology and interpretation of sedDNA results need to be considered in the context of species ecology, abundance, and DNA concentrations
Reconstructing Holocene fire records using dune footslope deposits at the Cooloola Sand Mass, Australia
No full textIn this study, we assess charcoal records from eolian deposits within the Cooloola Sand Mass, a subtropical coastal dune system in eastern Australia, to determine whether they can be used as a proxy for Holocene fire history. We excavate four profiles in depositional wedges at the base of dune slipfaces (footslope deposits) and calculate charcoal concentrations for three size classes (180-250 m, 250-355 m, and 355 m-2 mm) at predetermined depth intervals. Age-depth models are constructed for each profile using radiocarbon measurements (n = 46) and basal optically stimulated luminescence ages (n = 4). All records appear intact with little evidence of postdepositional mixing as demonstrated by minimal age reversals and consistent trends in charcoal concentration and accumulation rates (CHAR) among size classes. Combining all four records, we generate a ca. 7 cal ka BP terrestrial fire history that depicts distinct peaks representing periods of increased local fire activity at <0.3, 1.1-0.4, 2.2-1.6, 3.4-2.6, and 6.7-5.3 cal ka BP. Our findings parallel regional records and highlight the utility of dune footslopes as ecological and sedimentary archives. As dune fields are much more common than wetlands and lakes in semiarid and arid areas, these deposits have the potential to increase the spatial resolution of fire records globally
Start-up firms' investments: when economic policy uncertainty matters?
No full textPurpose: This study examines the impact of economic policy uncertainty (EPU) on investment decision-making of start-up firms in Japan. While existing literature suggests firms generally retrench investment under EPU, the authors argue that start-ups’ investment behaviours are likely different given the fact that start-ups always have to compete for survival. Design/methodology/approach: The authors investigate the impact of general economic policy and policy-specific uncertainty, including monetary policy, fiscal policy, trade policy and exchange rate policy uncertainty, on corporate investment of start-up firms using multiple fixed-effect regression. A wide range of robustness and endogeneity tests are conducted to ensure the validity and soundness of the empirical findings. Findings: The authors document a positive effect of EPU on start-up investment, to suggesting that the investment behaviour of start-ups is backed by venture capital distinct from that of mature firms. The results show that start-ups are more vulnerable during the changes in trade and exchange rate policies; uncertainties in monetary and fiscal policies do not restrain firms' investment. However, the effect varies in the cross-sections. Financial constraints have a moderating effect on the relation-ship between EPU on start-up investment. Institutional investors have an incremental effect on the positive relationship between EPU and start-up investment by encouraging risky investments. Originality/value: This is the first study to investigate how start-up investment is influenced by EPU, thus providing a new understanding of the investment behaviour of start-up firms during uncertainty. Further investigation sheds light on the roles of institutional and managerial ownership in this newfound relationship
Broad-host-range lytic Erwinia phage key with exopolysaccharide degrading activity
No full textIn this study, the genome of the lytic broad-host-range phage Key infecting Erwinia amylovora, Erwinia horticola, and Pantoea agglomerans strains was characterized. Key phage has a 115,651 bp long double-stranded DNA genome with the G + C ratio of 39.03%, encoding 182 proteins and 27 tRNA genes. The majority (69%) of predicted coding sequences (CDSs) encode proteins with unknown functions. The protein products of 57 annotated genes were found to have probable functions in nucleotide metabolism, DNA replication, recombination, repair, and packaging, virion morphogenesis, phage-host interaction and lysis. Furthermore, the product of gene 141 shared amino acid sequence similarity and conserved domain architecture with the exopolysaccharide (EPS) degrading proteins of Erwinia and Pantoea infecting phages as well as bacterial EPS biosynthesis proteins. Due to the genome synteny and similarity to the proteins of T5-related phages, phage Key, together with its closest relative, Pantoea phage AAS21, was suggested to represent a novel genus within the Demerecviridae family, for which we tentatively propose the name “Keyvirus”
Understanding New Zealand's environmental compliance through the 'eye in the sky'
Get PDFFreshwater resources in New Zealand are under increasing pressure.
Regulatory frameworks around on-farm environmental compliance have become more complex.
Farm plans that are used to identify risks and develop mitigation strategies for freshwater quality can be time consuming and costly to develop and monitor.
Can the ‘eye in the sky’, drones, help improve the efficiency of these processes
Pejorative suffixes and combining forms in English by José A. Sánchez Fajardo
No full textLike the first lines in a novel can set the tone for a book so do the opening lines of this book under review: ‘The need to semantically depreciate standard words is a linguistic universal. English therefore is no exception’ (p. 1). This is a rather polite way of saying humans need ways to express their dislike and even hatred of one another or of other things. While this may seem like a sad indictment of our species it is useful understanding the process by which these negative expressions develop
Dairy cows grazing plantain-based pastures have increased urine patches and reduced urine N concentration that potentially decreases N leaching from a pastoral system
Get PDFThe objective of this study was to determine the effect of grazing plantain-based pastures on urine volume, urination frequency, and urinary nitrogen (UN) concentration of dairy cows under a typical pastoral dairy practice offering approximately 25% supplemented feeds. The experiment was a completely randomised design with three pasture treatments (perennial ryegrass–white clover (RGWC); RGWC + low plantain rate (PLL); and RGWC + high plantain rate (PLH)), five replicate plots, and repeated in two sequential grazing periods. Forty-five lactating Friesian × Jersey cows were randomly assigned into three groups of 15 animals each to graze over six days in adaptation paddocks and three days in experimental plots. Urine flow sensors were used to measure urine volume and urinary frequency, while spot urine sampling was conducted to determine nitrogen (N) concentration in cow urine. The results showed that including 25% plantain in the diet (PLH) increased daily urine volume by 44% and the daily number of urinations by 28%, compared to grazing the RGWC pasture. In addition, N concentration in cow urine was decreased by 18 and 29% when the diet contained 18% and 25% plantain, respectively. In conclusion, under a typical dairy farm practice, incorporating plantain into the RGWC pasture with the proportion of 25% plantain in the diet can increase the number of urine patches and reduce the concentration of N in the urine, thereby providing the opportunity to decrease N leaching from pastoral systems