Wellington, May 5 : New, invasive plant-destroying insects, weeds and diseases will increasingly challenge New Zealand's borders as a warming climate makes plants and ecosystems more exposed and vulnerable, said a report released on Friday. New Zealand is already experiencing negative impacts of established invasive species, and future changes in land use and agricultural practices will exacerbate some of these impacts, said invasion ecologist Nicolas Meurisse, one of the authors of the "Global Change and New Zealand Biosecurity" report, published by the Better Border Biosecurity research collaboration. The report highlighted trends such as climate change, saying globally increasing pest emergences and movements will also challenge the ability to prevent future invasions, Meurisse said. The report is the culmination of a two-year government funded research project to review how global changes could impact New Zealand's plant biosecurity system and the various productive and natural ecosystems it protects, he said. "Biological invasions are already a big concern for New Zealand with its unique insular ecosystems and being home to one of the highest proportions of threatened indigenous species in the world," said the invasion ecologist, adding the country's economy is also very dependent on its primary sector. Megatrends such as changes in trade routes, extreme weather, sea and air currents, human movement, and international conflict are all likely to result in an increased risk of entry to New Zealand by "alien" plant pests, and thus affect New Zealand's plant border biosecurity systems, he said. One of the most predictable and impactful megatrends is rising CO2 levels and resulting warmer climates, Meurisse said, adding climate change will affect the growing environments and the pests and diseases that threaten them. The report found that existing crops, such as kiwi, citrus, grapes and avocados, may be grown in new areas as local climates change, and new crops may become viable, such as peanuts, soybeans, chickpeas, quinoa, oats, pineapple, banana and rice. These current and future crops, as well as plants in natural landscapes which can not be moved to suit warmer climates, will likely be threatened by new suites of pests, weeds and pathogens that may or may not already be present in New Zealand. The report calls for developing new methods to forecast, track and monitor changing border pressures, and better understanding the vulnerabilities of New Zealand plants and ecosystems and potential impacts of invasive pests and pathogens. /IANS