Spatial heterogeneities of human-mediated dispersal vectors accelerate the range expansion of invaders with source–destination-mediated dispersal

Abstract

Rapid range expansions of invasive species are a major threat to ecosystems. Understanding how invasive species increase their habitat ranges and how environmental factors, including intensity of human activities, influence dispersal processes is an important issue in invasion biology, especially for invasive species management. We have investigated how spatially heterogeneous factors influence range expansion of an invasive species by focusing on long-distance dispersal, which is frequently assisted by human activities. We have developed models varying two underlying processes of a dispersal event. These events are described by source and destination functions that determine spatial variations in dispersal frequency and the probability of being a dispersal destination. Using these models, we investigated how spatially heterogeneous long-distance dispersal influences range expansion. We found that: (1) spatial variations in the destination function slow down late population dynamics, (2) spatial variations in the source function increase the stochasticity of early population dynamics, and (3) the speed of early population dynamics changes when both the source and the destination functions are spatially heterogeneous and positively correlated. These results suggest an importance of spatial heterogeneity factors in controlling long-distance dispersal when predicting the future spread of invasive species.

Human-mediated dispersal drives the spread of the spotted lanternfly (Lycorma delicatula)

“…Our model predictions suggest that human-mediated dispersal is an extremely important driver of the spread of the SLF, and hence, we suggest future work focus on this component of SLF spread dynamics and forecasting. In a generalized modeling framework, research has explored how human-mediated dispersal accelerates the spread dynamics of invasive species 78 . Similar to a previous model that incorporated local spread dynamics (i.e., source [production] and destination [prob(establishment)]), our agent-based SLF spread model includes these same components that capture the effect of human-mediated dispersal of the SLF 78 .…”

“…In a generalized modeling framework, research has explored how human-mediated dispersal accelerates the spread dynamics of invasive species 78 . Similar to a previous model that incorporated local spread dynamics (i.e., source [production] and destination [prob(establishment)]), our agent-based SLF spread model includes these same components that capture the effect of human-mediated dispersal of the SLF 78 . For instance, we used both "local" SLF population densities in a given cell to directly influence the likelihood of whether a human-mediated dispersal event might occur, where higher densities of SLF led to more potential human-mediated movements.…”

Predicting the Global Distribution of Solenopsis geminata (Hymenoptera: Formicidae) under Climate Change Using the MaxEnt Model

“…These factors affect the shift in species distribution under natural conditions through active movement of the species themselves, resulting in a short-range dispersal and low dispersal speed. The dispersal speed is positively dependent on the population density of the species [51]. However, many invasive species display a high dispersal speed and long-distance dispersal, which are highly related to human activities [51][52][53], indicating that human-mediated dispersal accelerates the dispersal speed of invasive species, such as the emerald ash borer (Agrilus planipennis) in the USA [54] and the citrus flatid planthopper (Metcalfa pruinosa) in Korea [22].…”

“…The dispersal speed is positively dependent on the population density of the species [51]. However, many invasive species display a high dispersal speed and long-distance dispersal, which are highly related to human activities [51][52][53], indicating that human-mediated dispersal accelerates the dispersal speed of invasive species, such as the emerald ash borer (Agrilus planipennis) in the USA [54] and the citrus flatid planthopper (Metcalfa pruinosa) in Korea [22]. In particular, an increase in international trade and travel accelerates the dispersal of various invasive species on a global scale [55,56].…”

The establishment of plants following long-distance dispersal

“…(7) Impact. The effects of simultaneous invasions [26], aided by other factors that favor the invader [58,59], mean that human-mediated LDD can have a greater impact on local ecosystems than rare natural LDD events.…”