Invasive Species Richness Research Articles

Habitat fragmentation differentially affects invasive and native plant diversity in a human-dominated wetland island system

Managing invasive species requires identifying the factors that determine alien species invasion success. This study investigates how anthropogenic and biogeographical factors influence alien plant invasion in the Sanyang Wetlands, a human-dominated island system in Wenzhou City, China. Specifically, we analyzed whether human activities (e.g., habitat heterogeneity, proportion of road area, and cultivation) and island characteristics (e.g., island area, isolation) affect the diversity of native and invasive plant species similarly. We also assessed the applicability of the equilibrium theory of island biogeography to invasive plant species diversity and examined how these factors affect invasive plant species with different dispersal syndromes (anemochore, zoochore, and autochore). We found that both invasive and native species richness positively correlate with island area, habitat heterogeneity, and proportion of road area. However, although native species richness was negatively correlated with isolation, invasive species richness was not. The diversity and composition of invasive species with different dispersal syndromes were determined by different variables; for example, the composition and diversity of zoochores was increased by habitat heterogeneity, while anemochore species richness was increased by the proportion of road area, whereas anemochore species composition was influenced by distance to the nearest island. We conclude that habitat fragmentation differentially affects invasive and native plant diversity, aligning with the predictions of the equilibrium theory of island biogeography only for native species but not for invasive species. Our findings indicate that tailoring habitat attributes and regulating human activities could be effective strategies for mitigating the spread of invasive species in fragmented landscapes.

The influence of climatic and human-induced factors on the spatial distribution of invasive plant species richness across the Loess Plateau

Biological invasion poses a critical global issue, leading to substantial detrimental impacts on biodiversity, the environment, and the economy. The objective of the study is to offer a thorough understanding of how both climatic and human-induced elements impact the geographic richness of invasive plant species across the Loess Plateau. We evaluate the distribution of invasive plant species at the county level across the Loess Plateau by examining herbarium records from China. We incorporate 16 climatic and anthropogenic variables to depict the local environmental settings. Furthermore, we apply a classification and regression tree approach to investigate the correlation between the richness of invasive plant species and the identified factors. Our study demonstrates that a total of 401 invasive plant species are identified, which are spread across 249 genera and 61 families. Among these, the Asteraceae family stands out as the most prevalent, trailed by Poaceae and Fabaceae. The spatial distribution of invasive plant species richness reveals a notable trend, with the highest frequencies found in the southeastern parts of the region and the lowest in the northwestern areas. It is noteworthy that regions with higher levels of economic advancement tend to harbor a more significant abundance of invasive plant species. The richness of invasive plant species on the Loess Plateau is predominantly shaped by a combination of climatic and human variables, such as annual precipitation, gross domestic product, maximum temperature of warmest month, and minimum temperature of coldest month. To fully comprehend the ecological and biological mechanisms underlying the diversity of invasive plant species on the Loess Plateau, a pioneering conceptual framework has been established. Our study suggests that achieving a harmonious equilibrium among development, conservation, and invasion mitigation is essential for recognizing emerging risks associated with habitat alterations, climate change, and socio-economic advancements in arid regions.

Biochar soil addition alters ant functional traits as exemplified with three species

The response of soil microorganisms and plants in soil ecosystems to biochar is well recognised. However, biochars’ impact on large soil animal, such as ants, is inadequately understood, with only limited studies focusing on the abundance and mortality rates of some specific ant species. In this study, soil physicochemical properties, and ant community diversity and functional characteristics were compared between experimental plots with and without biochar application. No significant differences in soil (soil physicochemical properties) or ants (ant community richness, species abundance, and morphological characteristics) were observed between the two plots before biochar application. However, the biochar-treated plot soil surface temperatures, pH, and soil water content were significantly higher after 48 weeks. Biochar application promoted Cardiocondyla nuda (by 426%) and Formica japonica abundance (by 93%), but decreased Solenopsis invicta invasive ant species richness (by 54%), consistent with the fact that changes in soil properties were more beneficial to the former two species. In addition, in biochar-treated plots, F. japonica and S. invicta generally showed larger body size (18% and 6.7%), larger eyes (2.7% and 4.0%), and longer femurs (6.3% and 7.9%), which enabled them to respond better to potential barriers, such as plants. Our results highlighted that, besides species abundance and community structure, certain ant functional morphological indicators were also informative in evaluating biochar ecological implications.Graphical abstract

Environmental and anthropogenic drivers of invasive plant diversity and distribution in the Himalaya

Invasive alien species (IAS) are currently considered as one of the major causes of global environmental change. To manage the IAS, it is crucial to identify the different environmental and associated anthropogenic drivers that contribute to invasion of alien species in non-native regions. Although multiple drivers of invasion have been identified at a global scale, the relative roles of these are known to vary considerably at regional scales. Here, we investigate the role of key environmental and anthropogenic drivers in determining the diversity and distribution of selected invasive alien plant species in Kashmir Himalaya. We generated an extensive distribution dataset of these species through field sampling across the region and supplemented it with novel herbarium records. We also extracted data on the relevant environmental (climatic, soil and topographic) and anthropogenic drivers for the study region. The random forest model was employed to quantify the relative contribution of these drivers to determine the two common diversity metrics (species richness and abundance) of selected invasive alien plants. We found that soil water content followed by distance to city, the maximum air temperature, soil pH, soil temperature and human population density exerted the greatest influence on species richness of the invasive plants. Species abundance was significantly influenced by the maximum air temperature followed by soil temperature, distance to city, slope, soil pH and human population density. Overall, our findings help in disentangling the individual and interactive roles of multiple drivers of plant invasions, with wide-ranging implications for management in this Himalayan region and similar landscapes elsewhere.

Economic impact disharmony in global biological invasions

A dominant syndrome of the Anthropocene is the rapid worldwide spread of invasive species with devastating environmental and socio-economic impacts. However, the dynamics underlying the impacts of biological invasions remain contested. A hypothesis posits that the richness of impactful invasive species increases proportionally with the richness of non-native species more generally. A competing hypothesis suggests that certain species features disproportionately enhance the chances of non-native species becoming impactful, causing invasive species to arise disproportionately relative to the numbers of non-native species. We test whether invasive species with reported monetary costs reflect global numbers of established non-native species among phyla, classes, and families. Our results reveal that numbers of invasive species with economic costs largely reflect non-native species richness among taxa (i.e., in 96 % of families). However, a few costly taxa were over- and under-represented, and their composition differed among environments and regions. Chordates, nematodes, and pathogenic groups tended to be the most over-represented phyla with reported monetary costs, with mammals, insects, fungi, roundworms, and medically-important microorganisms being over-represented classes. Numbers of costly invasive species increased significantly with non-native richness per taxon, while monetary cost magnitudes at the family level were also significantly related to costly invasive species richness. Costs were biased towards a few ‘hyper-costly’ taxa (such as termites, mosquitoes, cats, weevils, rodents, ants, and asters). Ordination analysis revealed significant dissimilarity between non-native and costly invasive taxon assemblages. These results highlight taxonomic groups which harbour disproportionately high numbers of costly invasive species and monetary cost magnitudes. Collectively, our findings support prevention of arrival and containment of spread of non-native species as a whole through effective strategies for mitigation of the rapidly amplifying impacts of invasive species. Yet, the hyper- costly taxa identified here should receive greater focus from managers to reduce impacts of current invasive species.

The differences in plant invasion in two types of shorelines under flow regulation of the Three Gorges Reservoir

Riparian zones, crucial for linking fluvial and terrestrial habitats, are among the most diverse ecosystems. However, they are intensively invaded by alien plants, particularly in dam-regulated rivers. Therefore, understanding the mechanisms underlying plant invasion in dam-regulated river systems has become increasingly important, given that over two-thirds of global rivers are artificially regulated. Regulated rivers may flood upland areas or pristine riparian zones, resulting in shorelines developed from pre-upland and pre-riparian areas. However, differences in invasion intensities, adaptive strategies of invasive plants, and native species' resistance (namely the diversity-invasibility relationship) across these shorelines are unclear. To address these uncertainties, we performed field investigations in the Three Gorges Reservoir (TGR) on the upper Yangtze River, where both pre-upland and pre-riparian shorelines are present. Our findings indicate that pre-upland shorelines are more intensively invaded, showing higher relative richness and cover of invasive species. Invasive plants in this area displayed more conservative resource strategies and greater drought tolerance, exhibiting lower community-weighted mean (CWM) specific leaf area, higher CWM leaf dry mass content, and larger CWM seed mass. Pre-upland shorelines' invasibility decreased as the richness and cover of native species increased, a trend not observed in pre-riparian shorelines. The observed variations in plant invasion between the two shoreline types are primarily driven by differences in resident plant presence, soil moisture levels, and hydrological disturbances. This study provides valuable insights for policymakers and practitioners involved in managing invasive plants in regulated river ecosystems.

Landscape heterogeneity can partially offset negative effects of habitat loss on mammalian biodiversity in agroecosystems

Abstract Intensive, large‐scale agriculture promotes the conversion of natural habitats and diversified crops into monocultures, decreasing both native vegetation cover and landscape heterogeneity, leading to landscape simplification. Yet, a key knowledge gap persists on the relative impacts of the loss of native vegetation and landscape heterogeneity on biodiversity. Addressing this gap is pressing to support policies that conciliate agricultural production and biodiversity conservation and to move forward some scientific controversies, as the ‘land sharing versus land sparing’ and ‘habitat loss versus fragmentation’ debates. Through a hierarchical sampling design that maximised variation, while minimising correlation, between landscape heterogeneity and native vegetation cover, we recorded the occurrence of medium and large‐bodied mammals in native vegetation and agricultural areas of 55 landscapes in a global conservation hotspot and a key commodity production area—the Brazilian Savanna, Cerrado. We compared simple, additive and interactive models to investigate the effects of landscape heterogeneity and native vegetation cover on richness and composition of native and invasive mammals. Native and invasive mammal communities were affected by both native vegetation cover and landscape heterogeneity, although the effects of the first was stronger than the later. Both aspects had positive effects on native species richness and negative effects on invasive species richness, indicating that the loss of native vegetation and the reduction in landscape heterogeneity lead to biotic homogenisation. Yet, while landscape heterogeneity benefited most native species, the direction of its effect varied among invasive species and depended on native vegetation cover. Synthesis and applications. Besides reducing habitat loss, avoiding landscape homogenisation is key for conciliating agricultural production and biodiversity conservation, pointing to the relevance of policies encouraging crop diversification. As increasing landscape heterogeneity can in part compensate the negative effects of losing native habitat on biodiversity in agroecosystems, policies can gain feasibility by adjusting the balance between native vegetation cover and landscape heterogeneity according to what best suits local restraints and demands.

Spatial variation of soil seed banks along a gradient of anthropogenic disturbances in tropical forests on coral islands

Poor regeneration of natural vegetation is a major factor contributing to the degradation of tropical coral islands. Soil seed banks (SSB) are important for maintaining the resilience of plant communities. However, the community characteristics and spatial distribution of SSBs and the controlling factors along human disturbance on coral islands are unclear. To fill this gap, we measured the community structure and spatial distributions of forest SSBs on three coral islands in the South China Sea, with varying degrees of human disturbance. The results showed that strong human disturbance increased the diversity, richness, and density of SSBs, as well as increased the richness of invasive species. With increased human disturbance, the heterogeneity pattern of SSBs spatial distribution changed from difference between forest east and west to forest center and edge. The similarity between the SSBs and above-ground vegetation also increased, and the distribution of invasive species extended from the edge to the central area of the forests, demonstrating that human disturbance limited the outward dispersal of seeds of resident species but increased the inward dispersal of seeds of invasive species. Interaction between soil properties, plant characteristics, and human disturbance explained 23–45% of the spatial variation of forest SSBs on the coral islands. However, human disturbance reduced the correlations of plant communities and spatial distribution of SSBs with soil factors (i.e., available phosphorus and total nitrogen) and increased the correlations of the community characteristics of SSB with landscape heterogeneity index, road distance, and shrub and litter cover. Resident seed dispersal on tropical coral islands might be enhanced by reducing building height, constructing buildings in down-wind locations, and preserving corridors that support animal movement among forest fragments.

Effects of Invasive Plant Diversity on Soil Microbial Communities

Native plant communities can be invaded by different numbers of alien plant species or by the same number of alien plant species with different levels of evenness. However, little is known about how alien invasive plant species richness and evenness affect soil microbial communities. We constructed native herbaceous plant communities invaded by exotic plants with different richness (1, 2, 4 and 8 species) and evenness (high and low) and analyzed soil physico-chemical properties and the diversity and composition of soil fungal and bacterial communities by high-throughput Illumina sequencing. Overall, the species richness and evenness of invasive plants had no significant effect on bacterial and fungal alpha diversity (OTUs, Shannon, Simpson, Chao1 and ACE) or the soil physico-chemical properties. However, invasive species richness had a significant impact on the relative abundance of the most dominant fungi, Ascomycota and Bipolaris, and the dominant bacteria, Actinobacteriota, which increased with increasing invasive species richness. The relative abundance of the dominant microbial groups was significantly correlated with the relative abundance of some specific invasive plants in the community. This study sheds new light on the effects of plant co-invasion on soil microbial communities, which may help us understand the underlying mechanisms of multiple alien plant invasion processes from the perspective of soil microorganisms.

Impacts of Livestock Grazing on Vegetation and Soil in Lowland Grassland Ecosystem of Nepal

Livestock grazing is one of the largest sectors for land use globally, and contrasting impacts (negative, neutral, and positive) of livestock grazing on vegetation and soil have been observed. In Koshi Tappu Wildlife Reserve (KTWR), livestock grazing is one of the major problems but has been feebly addressed in previous research. This study, therefore, aims to determine the impacts of livestock grazing on vegetation and soil quality in grasslands of core and buffer zones of KTWR. Less grazing intensity was observed at the core zone compared to the buffer zone. Livestock grazing was observed with negative impacts on the richness and diversity of the plant species causing changes in the community assemblages. Invasive plant species richness, however, was found higher in the low grazed areas. Differences in soil pH, phosphorus, and potassium content between high and low grazed areas were not observed. In contrast, soil electrical conductivity, bulk density, and nitrogen content were significantly higher in the high grazed areas. Controlled grazing is recommended at buffer zone grasslands of KTWR to enhance plant diversity and nutrient availability. The core areas of the reserve should be managed for reducing the abundance and distribution of invasive alien plant species.

Diversity and Typology of Land-Use Explain the Occurrence of Alien Plants in a Protected Area.

Plant life history and functional characteristics play an important role in determining the invasive potential of plant species and have implications for management approaches. We studied the distribution of 24 alien plant taxa in a protected area in relation to different land-uses by applying ordination analyses and generalized linear models. Taxa richness is best explained by the presence of built-up areas, followed by residential areas, marshlands, and agricultural lands with semi-natural formations. The diversity of land-use within the grid cell proved to be an important explanatory factor, being the only significant variable explaining the richness of wood perennials and vines. The richness of annual herbs and seed-dispersed taxa is explained by a similar set of variables, with the exception of residential areas. The richness of invasive species is explained only by agricultural land and the diversity of land-use. The richness of taxa with predominant vegetative dispersal is best explained by built-up, marshland, and seminatural areas along with land-use diversity. When we consider only the presence of plant groups within grid cells, the results are similar. The results of similar studies may provide an important tool for defining sustainable practices and overall conservation management in protected areas.

Risk of Facilitated Invasion Depends Upon Invader Identity, Not Environmental Severity, Along an Aridity Gradient

Positive interactions can drive the assembly of desert plant communities, but we know little about the species-specificity of positive associations between native shrubs and invasive annual species along aridity gradients. These measures are essential for explaining, predicting, and managing community-level responses to plant invasions and environmental change. Here, we measured the intensity of spatial associations among native shrubs and the annual plant community—including multiple invasive species and their native neighbors—along an aridity gradient across the Mojave and San Joaquin Deserts, United States. Along the gradient, we sampled the abundance and species richness of invasive and native annual species using 180 pairs of shrub and open microsites. Across the gradient, the invasive annualsBromus madritensisssp.rubens(B. rubens),B. tectorum,B. diandrus, Hordeum murinum, andBrassica tournefortiiwere consistently more abundant under shrubs than away from shrubs, suggesting positive effects of shrubs on these species. In contrast, abundance of the invasive annualSchismusspp. was greater away from shrubs than under shrubs, suggesting negative effects of shrubs on this species. Similarly, native annual abundance (pooled) and native species richness were greater away from shrubs than under shrubs. Shrub-annual associations were not influenced by shrub size or aridity. Interestingly, we found correlative evidence thatB. rubensreduced native abundance (pooled), native species richness, and exotic abundance (pooled) under, but not away from shrubs. We conclude that native shrubs have considerable potential to directly (by increasing invader abundance) and indirectly (by increasing negative impacts of invaders on neighbors) facilitate plant invasions along broad environmental gradients, but these effects may depend more upon invader identity than environmental severity.

Assessing and Predicting the Distribution of Riparian Invasive Plants in Continental Portugal

The number of alien plant species is growing steadily across all world regions. These numbers tend to be exceptionally high in riparian ecosystems, often with substantial negative consequences for native species communities and ecosystem services provision. Here, we map the richness of invasive alien plant species in riparian ecosystems of continental Portugal, assess the relative importance of human and natural factors in shaping the uncovered patterns, and predict richness values along watercourses and at the municipal level for the whole study area. We found a higher richness of invasive alien plants in low altitudes and in downstream areas where human concentration is high. As time progresses, ongoing and increasing levels of socio-economic activity and globalization of plant trade will conceivably lead to a higher number of alien species becoming established. National and sub-national measures aiming to prevent and manage biological invasions in riparian ecosystems require coordinated efforts involving both local entities and those with responsibilities in the management of upstream catchment areas. These efforts must also be targeted to achieve future biodiversity protection goals as part of the EU Biodiversity Strategy for 2030.

Richness, not evenness, of invasive plant species promotes invasion success into native plant communities via selection effects

Native plant communities are often invaded by multiple alien species. It is still unclear how increasing diversity of alien invasive species suppresses the growth of native species and thus contributes to invasion success. In the subtropical monsoon region of southeast China, we experimentally created a native plant community with 18 herbaceous species. One week later, we let it be invaded by either zero (controls without invasion), one, two, four or eight alien plant species, with either high or low species evenness. After a four‐month growth period we harvested the aboveground biomass of each species. We found that increasing invasive species richness significantly increased invasive plant biomass, the biomass of all invasive and native plant species within the community, and invasion success (the ratio of invasive plant biomass to the biomass of all native and invasive plants), but it did not significantly reduce native plant biomass. Experimentally manipulating invasive species evenness did not influence invasion success and did not show any differential suppression effects on native plants. One invasive species,Sesbania cannabina, became dominant in terms of plant biomass, irrespective of its proportion in the alien plant mixtures. Throughout this experiment, effects of invasive species richness on invasion success were mainly due to such selection effects among the invasive species. On the other hand, the unchanged biomass of native species under increasing invasive plant richness suggests the presence of at least partly complementary resource niches between invasive and native species.

Vegetation, water infiltration, and soil carbon response to Adaptive Multi-Paddock and Conventional grazing in Southeastern USA ranches

We examine Adaptive Multi-Paddock (AMP) grazed with short grazing events and planned recovery periods and paired ranches using Conventional Continuous Grazing (CG) at low stock density on vegetation, water infiltration, and soil carbon across SE USA. Increased vegetation standing biomass and plant species dominance-diversity were measured in AMP grazed ranches. Invasive perennial plant species richness and abundance increased with AMP grazing in the south, while in the north they increased on CG grazed ranches. Percent bare ground was significantly greater in CG at the Alabama and Mississippi sites, no different at the Kentucky and mid-Alabama sites, and greater on AMP at the Tennessee pair. On average, surface water infiltration was higher on AMP than paired CG ranches. Averaged over all locations, soil organic carbon stocks to a depth of 1 m were over 13% greater on AMP than CG ranches, and standing crop biomass was >300% higher on AMP ranches. AMP grazing supported substantially higher livestock stocking levels while providing significant improvements in vegetation, soil carbon, and water infiltration functions. AMP grazing also significantly increased available forage nutrition for key constituents, and increased soil carbon to provide significant resource and economic benefits for improving ecological health, resilience, and durability of the family ranch.

Responses of Soil Microbial Community Size, Respiration Rate and Functional Diversity to Invasive Plant Species Richness

Responses of Soil Microbial Community Size, Respiration Rate and Functional Diversity to Invasive Plant Species Richness

Uloga riparijalnih oblasti u invaziji stranih biljnih vrsta

Biological invasions represent one of the defining features of the Anthropocene, causing major problems and incurring significant economic losses worldwide, which are only projected to increase in the future. Riparian zones, as critical transition zones, despite providing numerous ecosystem services, are exposed to a multitude of human pressures, making them highly vulnerable to plant invasions. In fact, in Europe, riparian areas are considered to be among the most vulnerable habitat types. As foci of invasive plant species richness, they play an important role in the process of their spread into nearby terrestrial ecosystems. Various disturbance events, both natural (i.e. floods) and artificial (e.g. hydro-morphological alterations), in addition to a strong propagule pressure these areas are subjected to, increase the invasibility of these vulnerable zones. Given their ecological importance and susceptibility to plant invasions, the preservation and restoration of riparian zones is especially important in light of climate change. In order to preserve and restore the ecosystem services and biodiversity of riparian areas, invasive alien plants have to be managed. The success of restoration measures and control activities can be affected by many variables, such as the invasive plants' residence time and their legacy effects. Furthermore, different environmental factors and drivers of invasion must also be considered, as they could potentially impair the restoration measures. Finally, a successful restoration effort depends on the inclusion of all the relevant stakeholders and their understanding of the importance of preventing and managing plant invasions.

How Biodiversity-Friendly Is Regenerative Grazing?

Regenerative grazing management (ReGM) seeks to mimic natural grazing dynamics to restore degraded soils and the ecological processes underpinning sustainable livestock production while enhancing biodiversity. Regenerative grazing, including holistic planned grazing and related methods, is an adaptive, rotational stocking approach in which dense livestock herds are rotated rapidly through multiple paddocks in short bouts of grazing to defoliate plants evenly and infrequently, interspersed with long recovery periods to boost regrowth. The concentrated “hoof action” of herds in ReGM is regarded vital for regenerating soils and ecosystem services. Evidence (from 58 studies) that ReGM benefits biodiversity is reviewed. Soils enriched by ReGM have increased microbial bioactivity, higher fungal:bacteria biomass, greater functional diversity, and richer microarthropods and macrofauna communities. Vegetation responds inconsistently, with increased, neutral, or decreased total plant diversity, richness of forage grasses and invasive species under ReGM: grasses tend to be favored but shrubs and forbs can be depleted by the mechanical action of hooves. Trampling also reduces numerous arthropods by altering vegetation structure, but creates favorable habitat and food for a few taxa, such as dung beetles. Similarly, grazing-induced structural changes benefit some birds (for foraging, nest sites) while heavy stocking during winter and droughts reduces food for seedeaters and songbirds. With herding and no fences, wildlife (herbivores and predators) thrives on nutritious regrowth while having access to large undisturbed areas. It is concluded that ReGM does not universally promote biodiversity but can be adapted to provide greater landscape habitat heterogeneity suitable to a wider range of biota.

Drivers of spontaneous plant richness patterns in urban green space within a biodiversity hotspot

Urban green space provides refuges for species that are unintentionally introduced by humans and which do not belong to the remnants of natural habitats in urban areas. However, the quantitative relationships between urban green space properties and these spontaneous species are unclear. To address this, we surveyed plant species occurring in urban green patches in Kunming city, which is located in a biodiversity hotspot in southwest China. We classified spontaneous plants into native, non-native and invasive plant species. A total of 386 spontaneous species belonging to 278 genera and 92 families were recorded in 190 patches. Most of the recorded species were herbaceous plants (76.2 %). While invasive species constituted a relatively small proportion of the total species pool (17.9 %), six out of ten of the most frequently occurring species were invasive. Regression models inspired by the theory of Island Biogeography show that total, native, non-native and invasive spontaneous species richness in urban green patches were best explained by the size of the ‘island’ (patch area), dispersal limitations (as expressed by ‘distance to city boundary’) and edge effects (as shown by the landscape shape index). While the set of drivers of spontaneous plants is similar for the different groups of species, the relative importance of each driver varies among them. Our study provides quantification of drivers of biodiversity patterns in urban green space. Based on this understanding, planning and management of urban green space can be adapted to maximize spontaneous plant conservation in rapidly urbanizing biodiversity hotspot regions.

Spatial distribution patterns of invasive alien species in China

The spatial distribution of invasive alien species is driven by various factors, and should be comprehensively evaluated based on multiple invasion indices and different taxonomic groups. In our study, we constructed three sets of invasion indices: (1) absolute invasive alien species (AIAS) richness; (2) weighted invasive alien species (WIAS) richness; (3) relative invasive alien species (RIAS) richness. First, we used principal component analysis (PCA) and k-means clustering to distinguish the invasion risk levels of 28 provinces in China. Then, the ordinary least squares (OLS) and partial least squares (PLS) regression methods were used to explore the factors predicting the distribution patterns of three sets of invasion indices for total species, plants and animals. Finally, the residuals’ regressions of alien plant species richness on alien animal species richness were used to evaluate the effect of environmental and anthropogenic factors on spatial congruence. Results showed that 17 provinces were identified as high invasion risk regions (Liaoning, Hebei, Shandong, Anhui, Jiangsu, Zhejiang, Hunan, Hubei, Jiangxi, Guangdong, Guangxi, Fujian, Taiwan, Hainan, Guizhou, Yunnan and Sichuan). For environmental factors, the potential evapotranspiration (PET) or actual evapotranspiration (AET) could better predict AIAS and WIAS richness, and area better predicted RIAS richness. For anthropogenic factors, the gross domestic product (GDP) or human population explained more variation in AIAS or WIAS richness, and transport volume or GDP could better explain the variation in RIAS richness. Generally, the environmental and anthropogenic factors showed identical prediction ability. The results of PLS regressions indicated that one set of predictors showed similar effects to the alien plants and animals within a model, and indicated the spatial distribution congruence of them. Removing the environmental and anthropogenic factors, to some extent, will weaken the congruence, but the congruence of plants and animals still exists for AIAS and RIAS richness. Our study provides meaningful information for the prediction and management of the biological invasions.