Forecasting climate suitability for Karnal bunt of wheat: A comparison of two meteorological methods

This paper compares two previously established meteorological modelling methods when determining areas in Western Australia (WA) where conditions are favourable for infection of wheat (Triticum aestivum) by Tilletia indica, the cause of Karnal bunt. There was a strong correlation (r = 0.83) between the Humid Thermal Index (HTI) model, which used long-term, average-monthly data, and the rainfall model, which was based on the per cent chance of at least three Suitable Rain Events (SRE) during the susceptible period (August to October). Results suggest that northern wheat growing areas are too hot and dry (HTI 3, chance of SRE 68-97%), eastern areas are marginal to too hot and dry (HTI around 2.2, chance of SRE 24-50%), and western areas are suitable (HTI between 2.2 and 3.3, chance of SRE 41-78%). The between and within year analysis indicated that infection was more likely to occur if anthesis occurred in northern areas in August, in October in southern areas, in September in eastern areas, and in August, September, and October in western and south-eastern areas. Model results suggest that data on HTI and SRE within each year may be more accurate in determining climatic suitability for Karnal bunt in WA, compared to long-term, average data. In the event that T. indica does successfully enter WA, it may be possible to limit spread of Karnal bunt through carefully planned sowing schedules

Seed dispersal of fleshy-fruited invasive plants by birds: contributing factors and management options

The ecology of seed dispersal by vertebrates has been investigated extensively over recent decades, yet only limited research has been conducted on how suites of invasive plants and frugivorous birds interact. In this review, we examine how plant fruit traits (morphology, colour and display, nutritional quality, accessibility and phenology), avian traits (fruit handling techniques, gut passage time and effect, bird movements and social behaviour and dietary composition) and landscape structure (fruit neighbourhood, habitat loss and fragmentation and perch tree effects) affect frugivory and seed dispersal in invasive plants. This functional approach could be used to develop generic models of seed dispersal distributions for suites of invasive plant species and improve management efficiencies. Four broad research approaches are described that could direct management of bird-dispersed invasive plants at the landscape scale, by manipulating dispersal. First, research is needed to quantify the effect of biological control agents on dispersal, particularly how changes in fruit production and/or quality affect fruit choice by frugivores, dispersal distributions of seed and post-dispersal processes. Second, we explore how seed dispersal could be directed, such as by manipulating perch structures and/or vegetation density to attract frugivorous birds after they have been foraging on invasive plant fruits. Third, the major sources of seed spread could be identified and removed (i.e. targeting core or satellite infestations, particular habitats and creating barrier zones). Fourth, alternative food resources could be provided for frugivores, to replace fruits of invasive plants, and their use quantified