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.

No abstract

Modeling techniques were developed to quantify the probability of Tilletia indica entering and establishing in Western Australia (WA), and to simulate spread, containment, and the economic impact of the pathogen. Entry of T. indica is most likely to occur through imports of bulk grain or fertilizer (0.023 +/- 0.017 entries per year and approximately 0.009 +/- 0.009 establishments per year). Entry may also occur through straw goods, new or second-hand agricultural machinery, and on personal effects of travelers who have visited regions with infected plants. The combined probability of entry and establishment of T. indica, for all pathways of entry, is about one entry every 25 years and one establishment every 67 years. Alternatively, sensitivity analysis does show that increases in quarantine funding can reduce the probability of entry to about one entry every 50 years and less than one establishment every 100 years. T. indica is spread efficiently through contaminated farm machinery, seed and soil, rain, air currents, and animals. Depending on the rate of spread of the pathogen and the amount of resources allocated for detection, the time until first detection could range from 4 to 11 years and the economic impact could range from 8 to 24% of the total value of wheat production in WA.

The objective of this paper was to use established meteorologi cal modelling methods to determi ne wheat growing regions in South Africa that would be favourable to infection by Til/etia indica, and to determine whether irrigation schedules influence climatic suitability for the pathogen. Under natural climatic conditions, only locations planted to rainfed spring-type wheat in the western and southern production regions of the Western Cape experienced climatic conditions suited to T indica development. Humid Thermal Indexes (HTI) were usually within the suitable range of 2.2 to 3.3 (HTI range 2.09-3.20, mean 2.58) and most locations experienced at least one Suitable Rain Event (SRE) (range 0.78-2.44) during the susceptible period. In contrast, central and eastern wheat growing regions in South Africa were likely to be too hot andlor dry under natural climatic conditions (HTI range 0.61-1.67, mean 1.06) and there was usually less than one SRE (range 0-0.63) for early and mid-planted wheat. HTI usually increased to levels within the suitable range for T indica development (HTI range 1.56-2.57, mean 2.14) in early-planted irrigated wheat. For mid-and late-planted irrigated wheat, HTI also increased, however, levels mostly remained below the minimum critical level of 2.2 (range 1.13-2.29, mean 1.59). These results indicate that in irrigated wheat, the later the crop is sown the less likely suitable climatic conditions for pathogen development will prevail. This may not apply to farms where crops are irrigated every 24 h, as minimum critical relative humidity (RH) is likely to be maintained and the probability of T indica spores surviving would potentially be increased. Farmers may need to consider altering irrigation schedules so that suitable climatic conditions for development and spread of T indica are limited.Keywords: climatic suitability, humid thermal index, relative humidity, suitable rain events *To whom corre~rondence ~hould be addre~~ed (rret()rza@~ci.lI()vs.ac.za)

Summary The distribution and rate of spread of the introduced weed bridal creeper, Asparagus asparagoides (L.) Wight, were calculated from the results of a questionnaire that was distributed to landholders in the south‐west of Western Australia. The weed was associated with regions that receive more than 350 mm of annual rainfall. There was a weak association between properties that had a longer history of disturbance through clearing of native vegetation and the presence of A. asparagoides. On a local scale, the questionnaire indicated that the rate of spread of A. asparagoides peaked at 0.6 m/yr of radial spread for patches of 10 m2. The rate of spread of A. asparagoides on a regional scale was calculated as 0.09 postcode regions per year. While 50% of respondents indicated that they attempted to control the weed, only 20% of land managers on neighbouring properties (usually roadside reserves) were involved in some type of weed control. The level of weed control also influenced rates of spread calculated for weed patches for the two groups. Asparagus asparagoides was not ranked highly as a weed by landholders, whereas government officials surveyed considered it the most important environmental weed.