非本土杂草占据着天然河道、一般土地和有用的农田。最初，对土地农产品产生直接影响并进而产生经济影响的植物被归类为杂草。尽管自20世纪70年代以来，人们对自然生态系统的认识不断加深，促使人们将这些植物归类为环境杂草。杂草不仅影响农产品，而且影响整个国家的生态系统(Arcioni, 2016)。1999年，澳大利亚政府公布了引起最多问题的植物物种名单，如国家重点杂草(WONS)。后来在2012年更新，现在包含32个分类单元(Thorp and Lynch, 2000)。这种杂草的例子包括新娘蔓藤和沃特索尼亚。
The non-native weeds occupy the natural watercourses, general lands as well as the useful agricultural land. Initially, the plants which showed direct influence on the land’s agricultural produce and hence had the economic impact were classified as weeds. Though since 1970s, the increasing consciousness about the natural ecosystem had encouraged to classify the plants as environmental weeds. The weeds not only affect the agriculture produce but also have influence on the entire ecosystem of the country (Arcioni, 2016). In 1999, the Australian government has released the list of plant species that causes most problems as the Weeds of National Significance (WONS). It was later updated in 2012 and now contains 32 taxa (Thorp and Lynch, 2000). The examples of such weeds include the bridal creeper and Watsonia.
The non-native plant species other than the weeds are some organisms, like Phytophtheracinnamomior commonly called as dieback fungus. This fungus attacks plant groups and is known to kill certain plant species, thereby causing disturbance in the natural environmental procedures. As per the Biodiversity conservation and control of introduced species in Western Australia Report (2011), the ecosystem of Western Australia, specifically the Stirling Range National Park faces severe threat from the dieback fungus. The plants like grevilleasand banksias found in this region are much more susceptible to the dieback fungus (Alexander, 1996).