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supported by Australian Research Council and Landcare Research NZ |
17th February 2009, at Auatralian National University, Canberra. |
SPEAKERS INCLUDE |
On Tuesday 17th February there will be an intensive 1-day research course offered, open to interested researchers, especially ECR and HDR.
The purpose of the remainder of the week for working group participants will be to discuss the potential impact of climate change on biological control of weeds, identify research priorities and develop a framework for predicting biological control of weeds under future climate conditions.
Background
Almost 50% of organisms on earth are made up of plants and herbivores and their interactions are powerful drivers shaping communities and ecosystems. For instance, herbivores influence the fitness of plants through both consumption and damage to host plant parts, which forms the basis of the argument behind using insect herbivores as biocontrol agents to control invasive plants in habitats. Changes in environmental physiology associated with current climate changes in particular elevated CO2 and temperatures, alterations in carbon-nitrogen ratio and reduced water availability are likely to have consequences on plant-herbivore interactions. Therefore understanding how these changes may affect plant-herbivore interactions is critical to predict future trends in biological control of invasive plants.
Atmospheric carbon dioxide and temperature are rising and are expected to affect ecosystem structures and functions. A range of studies have been carried out on the effects of elevated CO2 on plant growth and in general, elevated CO2 raises the photosynthetic rate, biomass, and water efficiency (in C3 plants), changes allocation pattern and anatomy and cuts nitrogen concentrations. In regard to plant-herbivore interactions alterations in allocation patterns and increased plant growth influence the quality of plants as food resources for herbivores. A reduction in foliar nitrogen levels for example, effect the nutritional quality for insect herbivores and might stimulate an increase in consumption or/and lengthen development times, which results in an increase vulnerability period to predators, parasitoids and pathogens.
Fewer studies have investigated the direct effect of elevated CO2 on aspects such as insect physiology and behaviour but there is a variety of studies available on indirect effects as described above where herbivores respond to changes in their host plants. The majority of studies concluded that under elevated CO2 conditions insect survival is expected to decrease. Less mobile feeding guilds such as leaf-mining insects, which are generally confined to one or two leaves for their larval development, are likely to be more sensitive to alteration in nutritional values of leaves than more mobile feeding guilds. This aspect would have significant implications on current and future biological control project of weeds involving different feeding guilds.
Plan-insect interactions provide the bases for biological control of invasive plants around the world and as new exotic weed problems are likely to increase following growing global trade and travel, biological control also increases and provides an effective and economical management technique. However, changes in environmental physiology associated with climate change are likely to change the selection and success of future biological control agents. Given the current understanding of the effects and speed of climate change, there is an urgent need to understand the impact and implications of aspects associated with climate change on biological control of invasive plants.
Last Updated January 2009
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