Invasion potential of Agrilus planipennis and other Agrilus beetles in Europe: import pathways of deciduous wood chips and MaxEnt analyses of potential distribution areas

Abstract

Bark‐ and wood‐boring beetles in the genus Agrilus (Coleoptera: Buprestidae) can survive wood‐chipping, and Agrilus planipennis has established in North America and European Russia with devastating impacts on forest ecosystems. The work presented in this paper combined import statistics of deciduous wood chips, Maximum entropy modelling (MaxEnt) of climatic similarities, and the distribution of potential tree hosts to predict the likelihood of four selected North American Agrilus species to become introduced and established in Europe. In agreement with the EU's energy‐policy target of increased use of wood chips, there was a linear or exponential increase in European imports of deciduous wood chips during the past 10 years from countries harbouring potentially harmful Agrilus species. MaxEnt showed high environmental suitability in Europe for the four selected Agrilus species, particularly in Eastern Europe and European Russia for A. anxius, A. bilineatus and A. planipennis and in southern Europe for A. politus. Documented susceptible host trees are widely distributed in the predicted areas of Agrilus distribution in Europe, and these areas receive large quantities of deciduous wood chips from countries where these and other Agrilus species are present. Thus, it was concluded that the fundamental conditions for introduction and establishment of Agrilus species in Europe are in place.

Minimum Winter Temperature as a Limiting Factor of the Potential Spread of Agrilus planipennis, an Alien Pest of Ash Trees, in Europe

“…The only attempt to predict the potential A. planipennis range in Europe by climatic variables was conducted using maximum entropy modelling [17]. This model has a number of serious flaws.…”

Pest survey card on Agrilus planipennis

“…Agrilus planipennis can tolerate high temperatures and shows remarkable thermal plasticity . Climatic conditions in the EU territory are generally not a limiting factor for EAB establishment and spread (VKM, 2014), and maximum entropy modelling (MaxEnt) shows a high environmental suitability overall for the EAB in Europe (Flø et al, 2015). Both mean temperatures and precipitation across Europe are suitable for the development of all life stages of the beetle, and there is not likely to be a climatic barrier to its establishment ( Figure 5).…”

Low Heat Availability Could Limit the Potential Spread of the Emerald Ash Borer to Northern Europe (Prognosis Based on Growing Degree Days per Year)

“…Climate and distribution of susceptible host plants are critical factors considered in predicting the potential distributions of alien species including A. planipennis [12]. Several prognoses of the potential range in Europe based on different approaches have been made [13][14][15]. Since the main factor limiting A. planipennis distribution is host availability, a high-resolution map of A. planipennis invasion risk for southern central Europe (Austria, Switzerland, Liechtenstein, southern Germany) was based on the distribution of ash trees F. excelsior [13].…”

“…Since the main factor limiting A. planipennis distribution is host availability, a high-resolution map of A. planipennis invasion risk for southern central Europe (Austria, Switzerland, Liechtenstein, southern Germany) was based on the distribution of ash trees F. excelsior [13]. Another model based on the maximum entropy modelling (MaxEnt) used the combination of 19 climatic parameters has shown that the regions of Europe adjacent to the known range of A. planipennis are suitable for this species; therefore, the climatic factors would not prevent the spread to adjacent regions [14]. The prognosis based on the minimum winter temperature as a possible limiting factor has shown that low winter temperatures would not prevent the spread of A. planipennis in all regions of Europe, except some eastern districts of European Russia [15].…”