Compete strongly with summer species for moisture and nutrient. Not known as a serious weed of natural ecosystems. Major displacement of annual grasses/ground covers. “Dense infestations occur in pastures and on river flats, producing a complete ground cover.” Likely to have a major impact on plants in the lower stratum (Victorian Invasive Plants). Thorn apple (recurved) competes strongly with summer species for moisture and nutrients. Although it displaces annual grasses, ground cover and riparian vegetation, it is not known to be a serious weed of natural ecosystems. Dense infestations occur in pastures and on river flats, producing a complete ground cover. The plants die in the cooler autumn weather. However, dead plants bear capsules that may remain standing through winter into spring (Agriculture Victoria). While perhaps not dominant year-round, can dominate plant communities in the summer at the very least, and standing skeletons may alter plant communities.

The plants die in the cooler autumn weather, but dead plants bearing capsules may remain standing through winter into spring.” Potential for a minor change in the frequency of fire risk within dense patches (Victorian Invasive Plants). An exhaustive Google/Google Scholar search did not reveal any additional evidence of this and the question defaults to a “no” answer at this time.

All parts of the plant are poisonous; covered with numerous slender spines. All parts of Datura plants contain dangerous levels of poison and may be fatal if ingested by humans and other animals, including livestock and pets (EOL). All Datura plants contain tropane alkaloids such as scopolamine, hyoscyamine, and atropine, primarily in their seeds and flowers. Because of the presence of these substances, Datura has been used for centuries in some cultures as a poison. There can be a 5:1 toxin variation between plants and a given plant's toxicity depends on its age, where it is growing, and the local weather conditions. These variations makes Datura exceptionally hazardous as a drug. In traditional cultures, a great deal of experience with and detailed knowledge of Datura was critical to minimize harm. Many tragic incidents result from modern users ingesting Datura. For example, in the 1990s and 2000s, the United States media contained stories of adolescents and young adults dying or becoming seriously ill from intentionally ingesting Datura. There are also several reports in the medical literature of deaths from D. stramonium and D. ferox intoxication. Children are especially vulnerable to atropine poisoning. Datura toxins may be ingested accidentally by consumption of honey produced by several wasp species, including Brachygastra lecheguana, during the Datura blooming season. It appears that these semi-domesticated honey wasps collect Datura nectar for honey production which can lead to poisoning. In some parts of Europe and India, Datura has been a popular poison for suicide and murder. From 1950 to 1965, the State Chemical Laboratories in Agra, India, investigated 2,778 deaths caused by ingesting Datura. The US Centers for Disease Control and Prevention reported accidental poisoning resulting in hospitalization for a family of six who inadvertently ingested Datura used as an ingredient in stew (Wikipedia). Devils trumpet grows naturally in disturbed areas such as eroded sites, old fields, vacant lots, overgrazed pastures and rangeland, roadsides and abandoned roadbeds, and fencerows (PIER). Dense infestations would have a minor effect on aesthetics. However, as the leaves produce an unpleasant odour when crushed and the fruit is armed with spines, some recreational activities may be affected. “Dense infestations occur in pastures and on river flats, producing a complete ground cover.” Likely to have a major impact on plants in the lower stratum. “Dense infestations occur in pastures and on river flats, producing a complete ground cover.” Likely to reduce available fodder for fauna species (Victorian Invasive Plants). All parts of the plant, particularly seeds, are toxic to livestock and humans. Rank smell and bitter taste usually deters stock from grazing plants (Weeds Australia). Dense infestations occur in pastures and on river flats, producing a complete ground cover. The plants die in the cooler autumn weather. However, dead plants bear capsules that may remain standing through winter into spring (Agriculture Victoria). Reports of human poisoning have occurred (CDC). All members of this genus contain narcotics and are very poisonous, even in small doses (PFAF).

Typically reaches a height of 0.6 to 1.5 metres (EOL). Erect annual or sometimes perennial herb, commonly 30 to 60 cm high. Unlikely to affect human access to recreational areas (Victorian Invasive Plants). An exhaustive Google/Google Scholar search did not reveal any evidence of this and the question defaults to a “no” answer at this time.