The global spread of invasive alien plants (IAPs) is intricately linked with human activities and climate change, posing significant threats to biodiversity and ecosystem stability (Catford et al., 2009; Bellard et al., 2012). The IAPs are introduced through human-mediated pathways such as agricultural practices, global trade and tourism, and the development of transportation corridors. These activities facilitate the spread of these species into various ecosystems (Dukes and Mooney, 1999; Pejchar and Mooney, 2009; Adhikari et al., 2021). Changing climatic conditions, coupled with human-induced habitat disturbances, accelerate the spread of invasive plant species by altering ecosystem dynamics and resource availability (Walther et al., 2009; Bellard et al., 2013). Furthermore, human intervention not only shapes societal progress but also significantly impacts ecosystem stability and biodiversity (González-Moreno et al., 2014).

In addition to human activities, rapid climate warming and globalization have accelerated the invasion and dispersal of IAPs worldwide. With global temperatures projected to increase by approximately 2.7 °C by the end of the century (Walther et al., 2009; Bellard et al., 2013; Ripple et al., 2024), the changing climate can alter ecological conditions, thereby shifting suitable habitats and enhancing the establishment and spread of IAPs (Bellard et al., 2013; Petitpierre et al., 2016). Human-induced environmental changes, combined with increasing temperatures, exacerbate the spread of IAPs, which highlights the need for proactive strategies to mitigate their impact on global ecosystems (Zimmermann et al., 2014; Liu et al., 2024).

Arundo donax, also known as giant reed, is a highly invasive, fast-growing perennial grass native to East Asia (Perdue, 1958; Pilu et al., 2012). It has been cultivated for thousands of years across Asia and Europe for various traditional applications, including the provision of construction materials, fencing, basket weaving, and reeds in woodwind instruments (Perdue, 1958; Bell, 1998; Guthrie, 2007; Jiménez-Ruiz et al., 2021). Over time, the species has been introduced into tropical, subtropical, and warm temperate regions worldwide, where it has naturalized and subsequently become invasive (Jiménez-Ruiz et al., 2021; Goolsby et al., 2023). Historical records indicate its introduction into North America during the early 1800s, South Africa during the late 1700s, and Australia during the mid-1800s, primarily for ornamental purposes and erosion control (Guthrie, 2007; Virtue et al., 2010; CABI, 2022). In recent decades, A. donax has been widely planted for additional purposes, including the production of walking sticks, fishing poles and musical instruments and as a potential biofuel source (CABI, 2022).

The species exhibits rapid growth, with an observed height increase of up to 10 cm per day, reaching a maximum height of approximately 7.62 m within a year and yielding nearly 25 tons of biomass per acre per harvest (Bell, 1998; Sidella, 2013; CABI, 2022; CISR, 2022). The primary mode of reproduction is vegetative propagation through rhizomes and plant fragments, enabling rapid colonization and regrowth following disturbance (Ozudogru et al., 2023). Dispersal occurs through both natural and anthropogenic mechanisms; notably, hydrological events such as flooding facilitate the downstream transport of rhizome fragments, whereas human-mediated activities, including soil displacement and intentional planting, significantly contribute to its widespread establishment (Bell, 1998; Guthrie, 2007; Goolsby et al., 2023).

Arundo donax is a highly adaptable species capable of thriving under a wide range of climatic and soil conditions, making it one of the most invasive plants globally. It can grow in regions with annual precipitation amounts ranging from 300 to 4000 mm and temperatures between 9 °C and 29 °C (Perdue, 1958; Weber, 2017; Haworth et al., 2019). Its remarkable drought resistance is due to its extensive underground system of rhizomes and deep roots that can penetrate up to 5 m into the soil, enabling it to access water and nutrients even under arid conditions (Sánchez et al., 2021). A. donax also demonstrates remarkable ecological plasticity, thriving across a wide range of soil types, including loose sandy soils, gravelly substrates, heavy clay, and riverine sediments (Jiménez-Ruiz et al., 2021; Goolsby et al., 2023). Its physiological adaptations, including a base growth temperature threshold of 9 °C and a high carbon dioxide exchange capacity, enable it to persist under diverse climatic conditions, ranging from warm to cold environments and humid to arid environments (Perdue, 1958; Spencer and Ksander, 2006). This extensive adaptability has led to its classification as one of the world’s 100 most invasive alien species (ISSG, 2011; CABI, 2022).

As a highly invasive species, A. donax exhibits profound ecological and economic impacts, particularly in riparian ecosystems, where it aggressively displaces native vegetation, alters soil nutrient dynamics, and increases fire hazards due to its high flammability (Ambrose and Rundel, 2007; Bruno et al., 2019). This highly invasive grass forms dense monospecific stands along waterways, thereby consuming nearly three times more water than native plants do, which is a major concern in areas with large-scale invasions, such as Australia, New Zealand, South Africa, the United States, and Mexico (Lambert et al., 2010; Virtue et al., 2010; Haddadchi et al., 2013; Nkuna et al., 2018; Jiménez-Ruiz et al., 2021). In South Africa, A. donax is the most abundant and widespread invasive alien grass species, and compulsory inclusion is legally required in invasive species control programs. Its dense growth disrupts the hydrological system, further reducing water availability in already water-scarce regions, making it a nationally recognized problematic invasive weed (Nkuna et al., 2018; Tshapa et al., 2021). Similarly, in California, A. donax exacerbates flood risks and fire hazards in riparian zones, with its dense, dormant biomass serving as a vertical fuel source that promotes the occurrence of wildfires and increases fire severity (Dudley, 2000; Quinn et al., 2007). Given its significant ecological and economic impacts, A. donax has become a priority for control and management efforts to mitigate further environmental and economic losses.

In recent years, species distribution models (SDMs) have emerged as critical tools for predicting the potential geographical distributions of species under changing climatic conditions (Araújo and Guisan, 2006; Franklin, 2013). Among the various SDMs, such as the maximum entropy (MaxEnt) algorithm, CLIMEX model, random forest (RF) models, generalized linear models (GLMs), and artificial neural networks (ANNs), the MaxEnt algorithm has gained widespread recognition for its effectiveness in modeling species distributions, particularly for IAPs (Booth et al., 2014; Byeon et al., 2018; Adhikari et al., 2022, 2025). The MaxEnt model is especially advantageous for analyzing presence-only data and provides notable performance even with limited sample sizes (Phillips et al., 2006; Yi et al., 2016). Despite its limitations, including the risk of overfitting, the MaxEnt model remains an effective tool for assessing invasion risk and guiding IAP management (Phillips et al., 2017). Its ability to integrate bioclimatic variables and simulate species distributions under current and future climate scenarios makes it invaluable for understanding and mitigating the ecological impacts of invasive species (Phillips et al., 2006; Wang et al., 2023).

Considering the highly invasive nature and global impact of A. donax on agriculture, nature, and the economy, further studies are needed to support the control and management of invasive weeds. In this study, global species occurrence records of A. donax are employed to estimate its invasion risk in various countries and predict invasion risk on the basis of bioclimatic variables under current and potential future shared socioeconomic pathway (SSP) climate change scenarios (SSP2-4.5 and SSP5-8.5). This research is designed to achieve three primary aims: (1) identify the key environmental variables influencing the distribution of A. donax, (2) predict the potential geographical distribution of A. donax under current and future climate change scenarios, and (3) classify the invasion risk levels of A. donax in different countries. By elucidating the invasion dynamics of this highly invasive species, this study aims to contribute to the development of early warning systems, prevention strategies, and targeted management plans. Ultimately, the findings of the study could support global efforts to mitigate the ecological and socioeconomic disruptions caused by A. donax invasions.

This study provides critical insights into the global invasion dynamics of A. donax, with significant implications for biodiversity conservation and invasive species management under the global environment change. The identification of HII as the most significant predictor of species distribution underscores the growing role of anthropogenic activities in facilitating biological invasions (Chen et al., 2021). Environmental factors such as temperature, soil quality, and resource availability govern habitat. Human activities such as urbanization, transportation network establishment, land use changes, and intentional species introductions, catalyze the establishment and spread of invasive species (Kueffer, 2017; Chen et al., 2021). These anthropogenic activities not only disrupt the ecological balance but also create pathways for colonization, particularly through coastal waterways, highways, and navigable rivers, which serve as conduits for invasive propagules (With, 2002; Catford et al., 2012). Furthermore, ecosystem modifications such as infrastructure expansion, nocturnal lighting, and hydrological changes increase invasion risk through the generation of disturbed habitats that favor nonnative species over native species (Okorondu et al., 2022).

Arundo donax exemplifies the profound influence of humans on invasion dynamics. Historically dispersed through intentional introductions for erosion control, biofuel production, and ornamental use, its global spread has been intensified by accidental transport via agricultural machinery and the nursery trade (Perdue, 1958; Bell, 1998; Haddadchi et al., 2013; Jiménez-Ruiz et al., 2021). Human-induced disturbances, including land development, agricultural runoff, and water management practices, create ideal conditions for A. donax dominance. Nutrient enrichment resulting from wastewater discharge and irrigation promotes soil fertility, enabling A. donax to outcompete native species, whereas mechanical disturbances, including bulldozing and tilling, can fragment A. donax rhizomes and stems, facilitating their vegetative reproduction and spread (Bell, 1998; Wijte et al., 2005). In fire-prone regions, human-induced burns enhance the competitive edge of A. donax, allowing rapid postfire recolonization while suppressing native vegetation recovery (Quinn et al., 2007; Goolsby et al., 2023). Given the notable influence of human activities on biological invasion, incorporating human factors, such as the HII, into invasion risk models increases the prediction accuracy, especially in regions with high levels of human activity (Bucklin et al., 2015; Zhu et al., 2017; Hong et al., 2021). In our study, the HII was the most critical environmental variable, with a significant contribution of 59% to the A. donax distribution modeling results (Figure 3A), underscoring the centrality of anthropogenic drivers in shaping its spread. Understanding these human-driven mechanisms is crucial for developing effective strategies to mitigate the spread and impact of IAPs and to preserve biodiversity and ecological balance.

Similarly, the annual mean temperature has second highest contribution in model prediction. Increasing temperature facilitates to expand the habitat of A. donax into the higher altitude and higher latitudes. The optimal temperature for A. donax germination varies between 20 °C and 30 °C (Bell, 1998), although it can tolerate a broader range of temperatures. However, temperatures below 0 °C can be detrimental to its growth (Bell, 1998; CABI, 2022). Given its preference for warm climates, A. donax has thrived in tropical, subtropical, and warm temperate regions, where it has adapted well to diverse soil types, including sandy gravel, heavy clay, and river sediments (CABI, 2022). Species resilience is highlighted by its ability to withstand increasing global temperatures, which have increased by approximately 1.1 °C since the late 19th century (Legg, 2021). This adaptability has facilitated an increase in the range of A. donax even under shifting climatic conditions. In support of this process, Bio 1 contributed significantly (23.60%) to the potential distribution of A. donax (Figure 3A), highlighting the dominant role of temperature in shaping its geographical spread.

Similarly, UV-B radiation plays a crucial role in determining the distribution of IAPs by influencing their competitive ability and survival (Hock et al., 2020; Mansinhos et al., 2024). While UV-B exposure can cause damage to DNA and cellular structures, leading to reduced growth rates and impaired reproduction, certain invasive species, such as A. donax, have developed adaptive mechanisms to thrive under high-UV and high-drought conditions (Liakoura et al., 1997; Mann et al., 2013). These adaptations include the production of UV-absorbing flavonoids and antioxidants, allowing them to exploit UV-driven changes in plant structure, nutrient cycling, and microbial interactions. In our study, UV-B radiation contributed 7.30% to the potential distribution of A. donax (Figure 3A). Although UV-B radiation can suppress invasive species by impairing their reproductive success, resilient species can withstand its effects, rendering UV-B radiation a key factor in predicting and managing plant invasions (Hock et al., 2020; Mansinhos et al., 2024).

With respect to bioclimatic factors, A. donax exhibits rapid growth, extensive roots, clonal reproduction via rhizomes, and notable tolerance to temperature and drought, increasing its invasiveness (Perdue, 1958; Guthrie, 2007; CABI, 2022). Initially, introduced for erosion control, bioenergy production, and ornamental landscaping, A. donax has become invasive because of its high germination rate, ability to regenerate roots, and adaptability to diverse climates (Virtue et al., 2010; CABI, 2022). By outcompeting native species, it reduces biodiversity and disrupts ecosystem functions such as hydrology, soil chemistry, and fire regimes. A. donax monopolizes sunlight, water, and nutrients, altering ecosystem dynamics and posing a threat to native flora and fauna (Waterworth, 2015). Our model revealed its presence in 145 countries under current climate conditions, covering approximately 10.15% of the global land surface. This study supports global risk assessments identifying A. donax as one of the most pervasive and damaging invasive species (Early et al., 2016), highlighting the urgent need for coordinated management strategies to curb its spread and mitigate its ecological impacts. Our findings indicated that areas in Africa, Asia, and South America are likely to exhibit a significant increase in suitable habitats for A. donax, with its spatial distribution projected to increase by up to 312.08% from 2081–2100 (Table 2). Increasing anthropogenic activities and temperatures could result in habitat loss for native species while facilitating a shift from unsuitable areas to those that are highly suitable for A. donax. This expansion of suitable conditions, combined with its rapid growth, will likely increase the invasion range of A. donax, as similar to other IAPs, such as Lantana camara, Oxalis latifolia, Parthenium hysterophorus and Acacia mearnsii (Ahmad et al., 2019; Tiwari et al., 2022; Poudel et al., 2023; Adhikari et al., 2024; Poudel et al., 2024).

The SSP5-8.5 scenario produced a greater invasion risk for A. donax from 2081–2100 than the SSP2-4.5 scenario did, with notable increases in South Korea, Mexico, Vietnam, and Turkey and new risks emerging in Bangladesh, India, the Netherlands, Sri Lanka, Japan, and Bhutan, where the invasion risk may exceed 50% (Supplementary Table S4). Extreme climate changes under SSP5-8.5 cause expansion in suitable habitats, especially at relatively high latitudes and elevations, while adversely affecting native plant communities, increasing their vulnerability to invasion (Chen et al., 2022). The synergistic effects of climate change and human-driven factors, such as land use changes, exacerbate the invasion risk under SSP5-8.5 (Adhikari et al., 2019; Yang et al., 2023), resulting in a greater threat of global invasion than that under SSP2-4.5.

Countries were classified into five categories on the basis of their risk of invasion by A. donax. Currently, 39 countries, including Denmark, Guinea, Kuwait, and Norway, have no recorded presence of A. donax (Table 3). However, climate change and human-driven activities, such as research, exploration, exploitation, and tourism activities, have significantly increased over the past 200 years, increasing the likelihood of invasion in several of these countries (Weir, 2017; Adhikari et al., 2023a, 2024). Projections for 2081–2100 indicated a substantial shift in invasion risk patterns, with the proportion of global land classified as no-risk areas expected to decrease to just 5%. Conversely, areas categorized as high-invasion risk areas and very high-invasion risk areas are projected to expand, encompassing 38% of the global land area under both the SSP2-4.5 and SSP5-8.5 scenarios (Figure 8). These findings highlight countries at potential risk of invasion, emphasizing the need for the implementation of quarantine measures to prevent the introduction and spread of A. donax.

The limited northward distribution of A. donax is due primarily to climatic and environmental constraints that restrict its growth and survival at relatively high latitudes. As a warm-season C4 grass, A. donax is highly sensitive to low temperatures and cannot tolerate freezing conditions, which are common in northern regions such as Canada, northern Europe, and Siberia (Quinn et al., 2007; Mack, 2008). These areas experience harsh winters, shorter growing seasons, and reduced solar radiation, all of which limit the ability of plants to establish and thrive (Perdue, 1958; Bell, 1998). Additionally, water availability is often restricted in frozen soils, and repeated freeze–thaw cycles can cause plant rhizome damage, impeding plant spread (Dudley, 2000).

Human-mediated pathways, such as urbanization, agriculture, and transportation networks, typically facilitate the introduction and proliferation of invasive species such as A. donax. However, such activities are less prevalent in colder, sparsely populated northern regions, significantly reducing opportunities for anthropogenic dispersal and colonization (Dudley, 2000; Hulme, 2009; Early et al., 2016). Additionally, the competitive advantage of A. donax in warmer, disturbed ecosystems decreases in areas with colder climates, where native flora are better adapted to local environmental stressors (Bell, 1998; Goolsby et al., 2023).

The key limiting factors for A. donax at northern latitudes include low average annual temperatures, extreme cold during the winter months, and minimal human activity (Franco et al., 2006; CABI, 2022; Goolsby et al., 2023). These conditions collectively reduce habitat suitability and restrict species range expansion. The interplay of climatic stressors, physiological limitations, and reduced anthropogenic influence underscores the challenges facing A. donax in colonizing higher-latitude areas (Goolsby et al., 2023).

Despite its negative impacts, A. donax has significant economic value. It is utilized for biomass energy production, edible and medicinal fungus cultivation, windbreak construction, soil conservation, and soil remediation (Speck, 2003; Liu et al., 2009; Fagnano et al., 2015; Vasmara et al., 2023). Various methods have been employed to control the spread of A. donax (for example, mechanical control, such as repeated mowing, may be relatively effective, but even small root fragments can regenerate new growth) (Bell, 1998). Systemic herbicides are often applied after flowering, either as a cut-stump treatment or a foliar spray, with late summer or fall as the most effective period for application (Hoshovsky, 1986; Bell, 1998). Since A. donax rarely produces viable seeds, it spreads primarily through vegetative fragments, with rhizome clumps and culm nodes serving as key colonization sources (Bell, 1998). Control efforts are labor intensive, requiring multiple sessions to eliminate root fragments and prevent regrowth, often making it a costly, long-term process that can last up to 20 years (Hoshovsky, 1986; CABI, 2022). To prevent ecological disruption caused by A. donax, comprehensive border control measures are essential. The implementation of rigorous biosecurity protocols can restrict its spread, protect native plant biodiversity, and create opportunities for ecosystem restoration.

Although our study provides valuable insights into the invasion risk of A. donax, several limitations should be noted. First, we used a single GCM model, and incorporating multiple models in future analyses could improve the robustness of projections. Second, our global-scale analysis employed a 2.5-minute resolution, which may not accurately capture invasion dynamics in small or geographically isolated areas such as islands. Third, our study relied on model-based projections, and while the identified risk areas are informative, field validation is currently lacking. Finally, we applied only the Maxent model, which does not account for dispersal barriers and may therefore lead to under- or overestimation of potential distributions.

Future research should address the limitations identified in this study by incorporating multiple GCMs to enhance the robustness of climate projections, applying higher spatial resolutions for regional and island-scale analyses, and integrating dispersal mechanisms to more realistically capture invasion dynamics. Beyond the MaxEnt framework, employing ensemble modeling approaches that combine multiple species distribution models could help reduce biases and provide more reliable predictions. Moreover, field-based validation of the predicted high-risk areas is essential to ground-truth model outputs and refine management strategies. Together, these efforts will improve the accuracy of invasion risk assessments for A. donax and provide stronger scientific guidance for prevention, monitoring, and control under current and future climate change scenarios.

Our study highlights the urgent need for coordinated international strategies to manage the invasion risk of A. donax, particularly in regions highly vulnerable to its spread. We recommend implementing early detection, rapid response, and biosecurity measures, supported by strict regulations on its trade and cultivation. The species could be introduced through commercial grass seeds used in pasturelands; therefore, quarantine systems should be properly managed. Our study provides a list of countries potentially at risk of future invasion, which could serve as a reference for policymakers. As the study is based on model predictions, the results may differ from real-world scenarios and should therefore be applied with caution, especially in areas lacking field evidence. Furthermore, collaborative research on sustainable management approaches, along with awareness programs for stakeholders and the public, will be essential to minimize the ecological and economic impacts of A. donax under changing climate conditions.

Arundo donax poses a significant threat to biodiversity, ecosystems, and local economies. The risk of invasion is heightened by global climate change and human activities. In this study, species distribution modeling was applied to assess the invasion potential of A. donax globally under various climate change scenarios. Among the nine environmental variables considered, the HII contributed the most to the model output, emphasizing the role of human activities in facilitating its spread. Currently, A. donax occupies approximately 10.15% of the world’s land area, but projections suggest that this value will increase to 25.66% from 2081–2100. The rate of invasion is particularly high in Africa, where it is expected to increase by up to 312.08%. Several countries, including South Africa, Morocco, Belgium, and Israel, are at high risk of invasion. The study identified regions with varying levels of invasion risk—low, moderate, high, and very high—along with emerging risks and expansion areas between 2041–2060 and 2081–2100. The future risk assessment results indicated that at least 20 countries will transition from no risk to low risk categories, and 42 countries will move from low to high and very high invasion risk categories. The results highlight the urgent need for the formulation of stringent quarantine measures and proactive management strategies to prevent the spread of these IAPs and mitigate their environmental and economic impacts.