Impact of fire on bellyache bush (Jatropha gossypiifolia) plant mortality and seedling recruitment

A 2-yr trial investigated the efficacy of fire as a control technique for bellyache bush (Jatropha gossypiifolia) in riparian habitats. Spring burns were applied in successive years (September 1999 and October 2000), and their impact on juvenile, mature and old bellyache bush plants was determined. Post-fire seedling recruitment was monitored for 21 months after the initial burn. The first fire significantly (P mature > old. In contrast, seedling emergence was significantly (P < 0.05) increased after burning. Emergence in burnt plots over the wet season following the first fire was 2.7-fold that in unburnt controls. Even with high mortality during the subsequent periods, seedling density in burnt plots at the end of the study averaged 368 000 per ha compared with 40 000 per ha in the unburnt controls. It is expected that the residual population of bellyache bush would produce enough seed to soon reinfest the area. These results stress that fire should be one of a number of tools, which may be used for control of bellyache bush. They also highlight the need for development of integrated control strategies that not only treat the primary infestations but also the many seedlings that emerge from the residual soil seedbank

Effect of dry heat on germination and viability of Cryptostegia grandiflora seeds

The present study described the effect of six dry heat intensities (28, 40, 60, 80, 100, and 200°C) and eight heat durations (0.5, 1, 2, 3, 6, 12, 24, and 36 min) on germination, viability, and germination rate of one-year-old seeds of the invasive weed rubber vine (Cryptostegia grandiflora R.Br.). Heat induced seed mortality is of significance to land managers, especially in pastoral areas, where prescribed burning is used to control rubber vine. There was a highly significant interaction between heat intensity and heat duration on germination, viability and germination rate of rubber vine seed. Seed germination was reduced once temperatures reached 80°C for more than 24 min. Raising the temperature to 100°C completely inhibited germination at 6 min and induced a total kill of seeds at 24 min. Further increases in dry heat to 200°C advanced inhibition of germination to 1 min and induced total kill of seeds at 3 min. Germination rate at 80, 100, and 200°C slowed down by 42, 65 and 91% of the original rate respectively. Above 80°C a negative correlation was detected between (i) germination response and heat duration, (ii) seed viability and heat duration, and (iii) germination rate and heat duration whereas seed viability was positively correlated with seed germination. The apparent tolerance to high temperature in rubber vine seeds indicates that high-intensity fires may be a requirement for maintenance of an effective seed management strategy in rubber vine infested habitats

Sap Flow and Water Consumption of Captain Cook Tree [Cascabela thevetia (l.) Lippold].

A two-year field study documented the diurnal and nocturnal sap flow rates and water consumption of young (YCC), adult (ACC) and mature (MCC) Captain Cook trees [Cascabela thevetia (L.) Lippold] that were invading a riparian habitat in northern Queensland. For comparison, two native trees [black tea tree (Melaleuca bracteata F. Muell.) and Moreton Bay ash (Corymbia tessellaris (F.Muell.) K.D.Hill & L.A.S.Johnson)] growing in association with Captain Cook tree were also monitored. Sap flow measurements were grouped into eight timeframes per day (early morning, late morning, early afternoon, late afternoon, early night, late night, early dawn and late dawn). Significant interactions in sap flow rate occurred between plant types, timeframes, and months. The magnitude of sap flow rate was Moreton Bay ash (YCC,ACC) and black tea tree(MCC). Maximum sap flow rates tended to occur during early (1-3 pm) to mid-afternoon (4-6 pm) for all age groups of Captain Cook tree and the two native trees. Diurnal sap flow rates were significantly greater than nocturnal, and on a monthly basis sap flow rates were highest over the spring to autumn period (September-May) and lowest during winter (June–August). Significant differences in water consumption also occurred between species and months. Water consumption peak time varied between plant types with most plants peaking in January except for MCC and Moreton Bay ash trees for which peak water consumption occurred in June and July respectively. Water consumption was high across all seasons except winter. The magnitude of water consumption was Moreton Bay ash, black tea tree (YCC,ACC,MCC trees). Moreton Bay ash registered maximal monthly water consumption (4700 L) compared with minimal consumption by MCC trees (55 L). On average, Captain Cook trees used 99% and 72% less water than Moreton Bay ash and black tea trees respectively. The significantly lower water consumption by Captain Cook trees compared with Moreton Bay ash and black tea trees may be offset by high population densities. Results also suggest that knowledge of optimal sap flow timeframes may be advantageous in exploring optimal timing for application of control operations related to management of Captain Cook trees

Can competition with pasture be used to manipulate bellyache bush (Jatropha gossypiifolia L.) population biology?

Bellyache bush (Jatropha gossypiifolia L.) is an invasive weed that poses economic and environmental problems in northern Australia. Competition between pasture and bellyache bush was examined in North Queensland using combinations of five pasture treatments (uncut (control); cut as low, medium, and high pasture; and no pasture) and four bellyache bush densities (0, 2, 6 and 12plantsm(-2)) in a buffel grass (Cenchrus ciliaris L.) dominated pasture. The pasture treatments were applied approximately once per year but no treatments were applied directly to the bellyache bush plants. Measurements of bellyache bush flowering, seed formation, and mortality were undertaken over a 9-year period, along with monitoring the pasture basal cover and plant species diversity. Maximum flowering rates of bellyache bush occurred after 9 years (97%) in plots containing no pasture, with the lowest rates of 9% in uncut control plots. Earliest flowering (322 days after planting) and seed formation (411 days) also occurred in plots with no pasture compared with all other pasture treatments (range 1314-1393 days for seed formation to occur). No seeds were produced in uncut plots. At the end of 9 years, mortality rates of bellyache bush plants initially planted averaged 73% for treatments with some pasture compared with 55% under the no-pasture treatment. The percentage of herbaceous plant basal cover in uncut plots was increased 5-fold after 9 years, much greater than the average 2% increase recorded across the low, medium, and high pasture treatments. The number of herbaceous species in uncut plots remained largely unchanged, whereas there was an average reduction of 46% in the cut pasture treatments. Buffel grass remained the species with the greatest basal cover across all cut pasture treatments, followed by sabi grass (Urochloa mosambicensis (Hack.) Dandy) and then red Natal grass (Melinis repens (Willd.) Ziska). These results suggest that grazing strategies that maintain a healthy and competitive pasture layer may contribute to reducing the rate of spread of bellyache bush and complement traditional control techniques such as the use of herbicides

MATERIAL ARQUEOLÓGICO [Material gráfico]

Copia digital. Madrid : Ministerio de Educación, Cultura y Deporte, 201

Διευρύνοντας το Μεθοδολογικό πλάισιο των Ολοκληρωμένων Μοντέλων Χρήσεων-Γης και Μεταφορών: Χωρικά Οικονομετρικά Μοντέλα και Αξιολόγηση Πολιτικών

323 σ.Στην παρούσα εργασία εξετάζεται η διεύρυνση του μεθοδολογικού πλαισίου των Όλοκληρωμένων Μοντέλων Χρήσεων-Γης και Μεταφορών σε κάθε επίπεδο. Οι προτεινόμενες βελτιώσεις αποσκοπούν στην αύξηση των ικανοτήτων πρόβλεψης, αξιοποιώντας τα οφέλη της μικροπροσομοίωσης σε τρείς διαστάσεις, άτομο, χώρο και χρόνο, με σκοπό να καταστόύν τα μοντέλα αυτά ευέλικτα εργαλεία αξιολοόγησης πολιτικών.In this research, the methodological framework of the Integrated Land-Use and Transport (LUTI) models is extended at every level. The objective of developing and implementing LUTI models is to predict the direct and indirect impacts of –transport and land-use– policies, on the environment, the society and the economy. The proposed improvements aim to increase the predicting capabilities of the current LUTI models, exploiting the strengths of microsimulation in three dimensions, agents, space and time, in order to render them flexible platforms for policy evaluation. The effects of the current economic crisis are discussed and explored throughout the doctoral dissertation. Aiming to decrease the required budget for a LUTI model development, public on-line data are used to a large part of the analysis. Moreover, a graph-theoretic solution for associations generation in synthetic simulation is suggested. Different types of spatial econometric models are used for the development of real estate price models, which form fundamental component of every LUTI model. Urban quality indicators (i.e. accessibility, population segregation, economic viability, available open space, housing affordability, land-use and social mix, and building density) are effectively employed manifesting the benefits of trans-disciplinary collaboration in urban planning. In this research, a policy evaluation methodology based on distributions rather than single aggregate measures of quality indicators is proposed. The results indicate that spatial econometrics effectively remove the spatial autocorrelation and achieve higher accuracy than the traditional linear regression, in predicting the dwelling prices. The impact of transportation infrastructure locations on real estate purchase prices and rents differs, depending on the type of the transit system. Qualitative transit infrastructure has preserved the real estate prices at higher levels during the crisis. Synthetic populations and real, on-line, crowdsourced data can efficiently be used for the development of LUTI models. Finally, agent-based LUTI models provide an opportunity for the development of an improved, flexible policy evaluation platform.Δημήτριος Β. Ευθυμίο

Effect of microwave radiation on seed mortality of rubber vine (Cryptostegia grandiflora R.Br.), parthenium (Parthenium hysterophorous L.) and bellyache bush (Jatropha gossypiifolia L.)

A trial was undertaken to evaluate the effect of microwaves on seed mortality of three weed species. Seeds of rubber vine (Cryptostegia grandiflora R.Br.), parthenium (Parthenium hysterophorous L.) and bellyache bush (Jatropha gossypiifolia L.) were buried at six depths (0, 2.5, 5, 10, 20 and 40 cm) in coarse sand maintained at one of two moisture levels, oven dry or wet (field capacity), and then subjected to one of five microwave radiation durations of (0, 2, 4, 8 and 16 min). Significant interactions between soil moisture level, microwave radiation duration, seed burial depth and species were detected for mortality of seeds of all three species. Maximum seed mortality of rubber vine (88%), parthenium (67%) and bellyache bush (94%) occurred in wet soil irradiated for 16 min. Maximum seed mortality of rubber vine and bellyache bush seeds occurred in seeds buried at 2.5 cm depth whereas that of parthenium occurred in seeds buried at 10 cm depth. Maximum soil temperatures of 114.1 and 87.5°C in dry and wet soil respectively occurred at 2.5 cm depth following 16 min irradiation. Irrespective of the greater soil temperatures recorded in dry soil, irradiating seeds in wet soil generally increased seed mortality 2.9-fold compared with dry soil. Moisture content of wet soil averaged 5.7% compared with 0.1% for dry soil. Results suggest that microwave radiation has the potential to kill seeds located in the soil seed bank. However, many factors, including weed species susceptibility, determine the effectiveness of microwave radiation on buried seeds. Microwave radiation may be an alternative to conventional methods at rapidly depleting soil seed banks in the field, particularly in relatively wet soils that contain long lived weed seeds

Data journalism beyond majority world countries:Challenges and opportunities

© 2019, © 2019 Informa UK Limited, trading as Taylor & Francis Group. This commentary reflects on the state of research on data journalism and discusses future directions for this line of work. Drawing on theory in international development and postcolonial studies, we discuss three critical pitfalls that we encourage future scholarship in this area to avoid. These include using a linear model of progress, in which journalists in Majority World nations struggle to ‘catch up’ to their Minority World counterparts because of the ‘obstacles’ they face; reproducing a simplistic split between the ‘West and the Rest’, thus missing the complex interaction of structures operating at different levels; and failing to examine journalistic agency due to an overemphasis on the technical structuring of the ‘tools’ used in data journalism. We also encourage scholars to engage in more comparative work rather than single case studies; increase dialogic communication between scholarship produced in, or about, different parts of the world; and incorporate more diverse methodologies with the aim of building theory. More broadly, we advocate for greater critical reflection upon—if not the challenging of—our dominant modes of thought in order to build more nuanced frameworks for explaining the complex causes, and potentially mixed effects, of data journalism around the world