Predicted spread based on the basic ecology of invasive alien species

The problem of invasive alien species in various regions and the difficulty of implementing countermeasures

Invasive alien species, organisms that have been taken out of their original habitat by humans and become established in a new one, can sometimes have negative effects on human society. Many may remember the sensation that arose in 2017, when the presence of highly venomous fire ants was confirmed in Japan for the first time. The cost of controlling invasive alien species is estimated to be well over 0 billion per year globally, and the problem of invasive alien species is now a major threat to society.
In order to mitigate or deter the negative effects of invasive alien species that have already been introduced or taken root, measures are being taken in many places to exterminate the target species and prevent their spread. However, in today’s increasingly globalized world, new invasive alien species are introduced every year. Furthermore, in many cases, by the time the negative effects of an invasive alien species become apparent, it has already spread over a wide area, at which point ad hoc responses are largely ineffective. In order to achieve effective countermeasures with limited labor resources, it is necessary to clarify the basic ecology of the target species, develop management techniques such as extermination based on that basic ecology, and develop a wide-area plan to determine how to spatially allocate the efforts to apply those techniques.

Future projections based on basic ecology and proper allocation of extermination efforts

Establishing a method for predicting the spread of the target species is an effective means for appropriately allocating management efforts spatially. This is akin to making a weather forecast that considers invasive alien species as bad weather. If a certain level of reliability can be ensured, despite the uncertainty, it will be possible to make a decision to carry out extermination activities or not based on the results, just like deciding whether or not to take an umbrella with you based on the probability of rainfall.

One of the themes we are working on in our laboratory is predicting the spread of invasive alien species. In recent years, we have been particularly active in research aimed at predicting the spread of target species by conducting computer simulations based on their basic ecology, which contributes to the efficiency of extermination measures. In recent examples, we conducted a study to predict the spread of white popinac, an invasive plant that is spreading in the Ogasawara Islands, and the red-necked longhorn beetle, an invasive insect that kills cherry and peach trees, and to identify areas where extermination efforts should be focused. Carrying this out requires both basic knowledge of the target species and the technology to handle high-performance computers, making this research a very interdisciplinary effort.


Department of Tourism Science, Graduate School of Urban Environmental Sciences
Accociate Professor
OSAWA Takeshi

Completed doctoral program at the Graduate School of Human Development and Environment, Kobe University. In current role since 2018.