Plant Invasion

Biodiversity and sustainable development in Sub-Saharan Africa (SSA) are considerably impacted by invasive alien plants (IAPs). Increasing plant invasions in SSA threaten agricultural productivity, biodiversity conservation, and other socioeconomic activities, which in turn put the United Nations Sustainable Development Goals (SDGs) in peril. In order to effectively combat IAPs, understanding their functional traits (morphological, physiological, and phenological traits) and integrating them into remote sensing (RS) is vital. While functional traits influence IAPs’ fitness to invade and establish in a new geographical range, RS aids in studying them remotely, delineating and mapping them, and predicting their potential invasions. The information on this study topic was gathered by reviewing various existing studies published between 2000 and 2024. Based on this review, it was deduced that the majority of IAPs are fast-growing (or acquisitive), with a shorter leaf lifespan, bigger leaves, and higher plant height, ultimately resulting in a higher resource acquisition ability. We established further that in SSA, there are limited studies on IAP functional traits and their integration in RS. Many studies conducted in the region focus mostly on IAP distribution. Evidence from prior studies revealed that functional trait remote sensing (FTRS)-based research not only improves detection and mapping but also predicts whether a certain alien plant can become invasive or expand its distribution range. Thus, using the FTRS approach could help IAP management in SSA, ultimately achieving the SDGs. Our review discusses IAP implications in SSA (e.g., Angola, Tanzania, Benin, Kenya, Uganda, Rwanda, Zambia, Burundi, Zimbabwe, Botswana, Malawi, etc.) and for the achievement of SDGs; functional traits and their impact on alien invasions; and the importance of incorporating functional traits into RS. Full article

Soybean is a high-value food source, and the invasive weeds Mexican prickly poppy (Argemone ochroleuca) could release allelochemicals that inhibit the growth of this crop. The impact of A. ochroleuca on the germination and growth of soybean is not well documented. Therefore, the aim of this study was to evaluate the TLC profiles of different extracts of A. ochroleuca and assess the effects of extracts on the germination of soybean seeds. Shoots and roots of A. ochroleuca were weighed and 100 g of each was separately extracted with 1000 mL deionized water, hexane or acetone. Ten concentrations of water extracts ranging from 10 to 100 mL per 100 mL of deionized water and three concentrations of acetone and hexane extracts ranging from 2.5 to 7.5 g/L were separately used for seed germination bioassays. Thin-layer chromatography (TLC) analysis was used to compare the chemical profiles in the shoot and root water, and in the hexane and acetone extracts of A. ochroleuca. The highest reduction was recorded from the water extract, at 100%. The TLC profiling of A. ochroleuca addressed different classes of compounds, including alkaloids, phenolic acids and flavanoids. There is, however, a need to identify the most active phytochemicals in the suppression of germination. Full article

Phytolacca americana, introduced to China in the 20th century for its medicinal properties, has posed a significant ecological and agricultural challenge. Its prolific fruit production, high reproductive coefficient, adaptability, and toxic roots and fruits have led to the formation of monoculture communities, reducing native species diversity and posing threats to agriculture, human and animal health, and local ecosystems. Understanding its potential distribution patterns at a regional scale and its response to climate change is essential for effective monitoring, management, and control. In this study, we utilized the Maxent model to simulate potential habitat areas of P. americana across three timeframes (current, 2050s, and 2070s) under three climate change scenarios (SSP126, SSP245, and SSP585). Leveraging data from 556 P. americana sites across China, we employed ROC curves to assess the prediction accuracy. Our findings highlight key environmental factors influencing P. americana’s geographical distribution, including the driest month’s precipitation, the coldest month’s minimum temperature, the wettest month’s precipitation, isothermality, and temperature annual range. Under current climate conditions, P. americana potentially inhabits 280.26 × 10⁴ km² in China, with a concentration in 27 provinces and cities within the Yangtze River basin and its southern regions. While future climate change scenarios do not drastically alter the total suitable area, the proportions of high and low-suitability areas decrease over time, shifting towards moderate suitability. Specifically, in the SSP126 scenario, the centroid of the predicted suitable area shifts northeastward and then southwestward. In contrast, in the SSP245 and SSP585 scenarios, the centroid shifts northward. Full article

Palmate-leaved morning glory (Ipomoea cairica (L.) Sweet) is a fast-growing perennial herbaceous twining vine that was recently discovered to invade mangrove wetlands in China. To understand the mechanism of its successful invasion, the salt tolerance of a coastal ecotype from Zhuhai and a terrestrial ecotype from Guangzhou were compared under salt stress. The morphological, physiological, and biochemical parameters related to growth, ion homeostasis, photosynthetic pigments, chlorophyll fluorescence parameters, oxidative stress, and apoptosis were measured in both ecotypes. Monitoring apoptosis showed that the protoplasts of the coastal ecotype underwent apoptosis and were later compared with those of the terrestrial ecotype. The coastal ecotype was also found to have higher regenerated stems; less water loss, sodium (Na⁺) uptake, and membrane damage; higher salt gland density and area; and better photosynthetic performance than the terrestrial ecotype. The coastal ecotype probably prevented salt-related damage by reducing its water loss and secreting excess Na⁺ through its lower stomatal density and higher density and area of salt glands. The coastal ecotype also maintained a better balance of Na⁺, potassium ions, nitrogen, and phosphorus under salt stress. Moreover, the coastal ecotype had higher activities of antioxidant enzymes, including superoxide dismutase, peroxidase, and catalase, and a higher content of non-enzymatic antioxidants, including proline and anthocyanins, which indicate a stronger antioxidant ability. Our results suggest that the coastal ecotype adapts to a higher salt tolerance than the terrestrial ecotype by enhancing its exclusion of salt, adjusting its osmolytes, and through photosynthetic efficiency, which could explain its successful invasion in the mangrove wetland ecosystem. Full article

Chinese tallow is a non-native invasive tree expanding in range and abundance throughout the southern United States. Several biogeographical studies mapping tallow distribution and examining key underlying environmental factors relied on the U.S. Forest Service Forest Inventory and Analysis (FIA) data, representing forestlands at scales of ~2400 ha. However, given that most invasive trees, like tallow, are cosmopolitan and dynamic in nature, FIA data fails to capture the extent and severity of the invasion especially outside areas classified as forestlands. To develop tallow maps that more adequately depict its distribution at finer spatial scales and to capture observations in non-forestlands, we combined verified citizen science observations with FIA data. Further, we described spatiotemporal patterns and compared citizen science to FIA and other previously published distribution maps. From our work, although tallow is prevalent in the south, Louisiana, Texas, and Mississippi were the most invaded states. Tallow was associated with flatwoods and prairie grasslands of the Gulf Coast. Annual extreme minimum temperatures of less than −12.2 °C (10 °F) represented the northern limit of naturalized tallow populations. Tallow’s northward and inland expansion was captured in citizen science and FIA data, indicating a tallow spread rate ranging from 5 to 20 km annually over the last decade. Systematic sampling, such as FIA, and citizen science data both have their own unique pitfalls. However, the use of citizen science data can complement invasive plant distribution mapping, especially when combined with data from established systematic monitoring networks. This approach provides for a more complete understanding of invasive tree extent and spatiotemporal dynamics across large landscapes. Full article

The Revillagigedo Archipelago, located in the Eastern Pacific Ocean, stands out for its unique biological richness and endemism. These islands remained uninhabited until the second half of the twentieth century, allowing a better conservation status than on other oceanic islands. However, the continuous introduction of potentially invasive alien plant species, and the lack of adequate control or eradication actions, jeopardize the conservation and restoration of these islands’ fragile ecosystems. We present the most complete vascular plant species inventory and an updated list of alien plant species of the Revillagigedo Archipelago, which was compiled through an extensive review of national and international plant collections and other sources. Our 272 species list includes 106 alien plant species (39.3%; 104 in Socorro, and 16 in Clarion): 67 (24.8%) are naturalized, 14 (5.2%) are casual aliens, and 25 (9.3%) subsist under cultivation. The documented alien species belong to 73 families. Annual and perennial herbs are the prevailing life forms in the alien flora, while naturalized species are primarily native to North America. The number of introduced species has increased significantly since the islands became inhabited. Many of the recently introduced species pose a major invasion risk like on other islands of the world. Full article

Sorghum halepense competes with crops and grass species in cropland, grassland, and urban environments, increasing invasion risk. However, the invasive historical dynamics and distribution patterns of S. halepense associated with current and future climate change and land-use change (LUC) remain unknown. We first analyzed the invasive historical dynamics of S. halepense to explore its invasion status and expansion trends. We then used a species distribution model to examine how future climate change and LUC will facilitate the invasion of S. halepense. We reconstructed the countries that have historically been invaded by S. halepense based on databases with detailed records of countries and occurrences. We ran biomod2 based on climate data and land-use data at 5′ resolution, assessing the significance of environmental variables and LUC. Sorghum halepense was widely distributed worldwide through grain trade and forage introduction, except in Africa. Europe and North America provided most potential global suitable habitats (PGSHs) for S. halepense in cropland, grassland, and urban environments, representing 48.69%, 20.79%, and 84.82%, respectively. The future PGSHs of S. halepense increased continuously in the Northern Hemisphere, transferring to higher latitudes. Environmental variables were more significant than LUC in predicting the PGSHs of S. halepense. Future PGSHs of S. halepense are expected to increase, exacerbating the invasion risk through agricultural LUC. These results provide a basis for the early warning and prevention of S. halepense worldwide. Full article

Predicting the likelihood that non-native species will be introduced into new areas remains one of conservation’s greatest challenges and, consequently, it is necessary to adopt adequate management measures to mitigate the effects of future biological invasions. At present, not much information is available on the areas in which non-native aquatic plant species could establish themselves in the Iberian Peninsula. Species distribution models were used to predict the potential invasion risk of (1) non-native aquatic plant species already established in the peninsula (32 species) and (2) those with the potential to invade the peninsula (40 species). The results revealed that the Iberian Peninsula contains a number of areas capable of hosting non-native aquatic plant species. Areas under anthropogenic pressure are at the greatest risk of invasion, and the variable most related to invasion risk is temperature. The results of this work were used to create the Invasion Risk Atlas for Alien Aquatic Plants in the Iberian Peninsula, a novel online resource that provides information about the potential distribution of non-native aquatic plant species. The atlas and this article are intended to serve as reference tools for the development of public policies, management regimes, and control strategies aimed at the prevention, mitigation, and eradication of non-native aquatic plant species. Full article

Aeolesthes sarta or Trirachys sarta is a polyphagous long-horned beetle that has caused severe damage to the Populus alba forests/plantations in its regions of origin. Climate change could accelerate the introduction and spread of invasive pest species, potentially causing ecological damage and economic losses. Furthermore, globalization and increased trade can inadvertently transport pests across borders into regions where they do not already occur. Hence, it is crucial to identify areas where the climate is most suitable for the establishment of A. sarta’s and which areas of the world are suitable for the growth of P. alba under climate change scenarios. This study employed the CLIMEX model to estimate the potential global distribution of A. sarta and its correlation with its dominant host, P. alba, under current climatic conditions and potential future scenarios, namely the A1B and A2 climate change scenarios (CCSs). Under current climatic conditions, the model indicates that the establishment of a climatically suitable habitat for A. sarta extends beyond its current known range. The model estimated that, under the world’s current climatic conditions, 41.06% of the world can provide suitable areas (EI > 0) for the survival of A. sarta. For P. alba, under the current climatic conditions, suitable regions for the growth of P. alba are present in all continents (excluding Antarctica); under the world’s current climatic conditions, 53.52% of the world can provide suitable areas for the growth of P. alba (EI > 0). Climate change will significantly alter the number of suitable habitats for A. sarta development and P. alba growth globally. In future climatic conditions, the number areas capable of supplying suitable habitats (EI > 0) for A. sarta will slightly decrease to 40.14% (under A1B and A2 CCSs), while, for P. alba, the number areas capable of supplying suitable habitats will also marginally decrease to 50.39% (under A1B scenario), and this figure is estimated to drop to 48.41% (under A2 scenario) by the end century (2100). Asia, Europe, North America, South America, and Oceania have a high percentage of highly suitable areas for A. sarta development and P. alba growth under current climatic conditions; however, according to estimates of future climatic conditions, by the end century, only Asia, Europe, North America, and Oceania will have a high percentage of highly suitable areas for A. sarta development and P. alba growth. The range of highly suitable habitats is likely to increase in the northern hemisphere; however, this range is expected to shrink with regards to the southern hemisphere. The range contraction was higher under the A2 climate change scenario due to a higher warming trend than in the A1B scenario. Due to climate change, the range of A. sarta development shifted, as did the P. alba growth range, which, thanks to the suitable environmental conditions for the growth of P. alba, makes all those regions vulnerable to the introduction and development of A. sarta. Strict monitoring, prevention, and control measures at borders, airports, and seaports before the trade of P. alba and other suitable host species wood (logs/billets) are highly recommended to prevent the spread of A. sarta and ensure biodiversity security. It is expected that the A. sarta and P. alba climate models presented here will be useful for management purposes since both can be adapted to guide decisions about imparting resources to regions where the threat of pest invasion remains and away from regions where climate suitability is predicted to decrease in the future. Full article

Invasive C₄ grasses can inhibit the natural regeneration of secondary forest in tropical landscapes after the cessation of intensive use for grazing and agriculture. In Panama, invasive Saccharum spontaneum forms dense stands that require active management to re-establish forest successional processes. In this region, restoration strategies typically involve clearing grass cover manually and applying fertilizer prior to planting tree seedlings. However, if fertilizers alleviate nutrient limitation and enhance grass competition with tree seedlings, these practices may exacerbate the costs of Saccharum control and hamper restoration goals. Here, we evaluated how S. spontaneum responds to nitrogen and phosphorus addition in the field to determine whether S. spontaneum is nutrient limited in this system. S. spontaneum was limited by both nitrogen and phosphorus, as revealed through increased foliar nutrient concentrations. S. spontaneum biomass was significantly greater in both nitrogen and phosphorus addition plots after both the first growth period (early rainy season) and second growth period (late rainy season), with stronger effects of nutrient limitation during the second growth period for both N limitation and N and P co-limitation. Nutrient limitation in S. spontaneum highlights a potential risk of fertilizer applications during restoration, agriculture, and agroforestry activities in which invasion of this aggressive weed is a challenge to land management. Full article

Plant invasions are closely related to environmental filtering and biointeractions; however, the variations in invasive plant niches along latitudinal gradients in heterogeneous habitats remain unclear. In this study, we conducted a two-year survey in China spanning 21° N–37° N to explore the niche characteristics of plant species within communities invaded by the amphibious alien weed Alternanthera philoxeroides in both terrestrial and aquatic habitats as well as their latitudinal trends. We found that A. philoxeroides had the greatest niche breadth in the studied communities. The species pairs with the highest niche similarity were A. philoxeroides–Digitaria sanguinalis in terrestrial communities and Cyperus rotundus–Kyllinga brevifolia in aquatic communities. The niche similarity between A. philoxeroides and its accompanying species in terrestrial habitats was significantly higher than that in aquatic habitats (t = 5.954; p < 0.001). The niche breadth of A. philoxeroides had no obvious latitudinal trend, while the niche breadth of its accompanying species in the terrestrial community significantly decreased with increasing latitude (F_{7, 57} = 4.364, p = 0.001). In the terrestrial communities, the niche similarity between A. philoxeroides and its accompanying species significantly decreased with increasing latitude (F_{7, 57} = 3.671, p = 0.003), while the niche overlap significantly increased with increasing latitude (F_{7, 57} = 8.916, p < 0.001). However, the aquatic species’ niche characteristics had no obvious latitudinal trends. These findings indicated that habitat heterogeneity significantly affected the species’ niche characteristics in A. philoxeroides-invaded communities. Environmental filtering at low latitudes allowed the invasive and accompanying species to evolve similar niches, while the cold climate at high latitudes increased the niche overlap between the invader and accompanying species. Our findings are crucial for predicting the dynamics of invasive plant communities under global change and for understanding the mechanisms of species coexistence. Full article

Predicting the direction and magnitude of change in soil dynamics caused by invasive plant species has proven to be difficult because these changes are often reported to be species- and habitat-specific. This study was conducted to determine changes in three soil properties, eight soil ions, and seven soil microelements under established stands of four invasive plants, Prosopis juliflora, Ipomoea carnea, Leucaena leucocephala, and Opuntia ficus-indica. Soil properties, ions, and microelements were measured in sites invaded by these four species in southwest Saudi Arabia, and these values were compared to the results for the same 18 parameters from adjacent sites with native vegetation. Because this study was conducted in an arid ecosystem, we predict that these four invasive plants will significantly alter the soil properties, ions, and microelements in the areas they invaded. While the soils of sites with the four invasive plant species generally had higher values for soil properties and ions compared to sites with native vegetation, in most instances these differences were not statistically significant. However, the soils within sites invaded by I. carnea, L. leucocephala, and P. juliflora had statistically significant differences for some soil parameters. For sites invaded by O. puntia ficus-indica, no soil properties, ions, or microelements were significantly different compared to adjacent sites with native vegetation. Sites invaded by the four plant species generally exhibited differences in the 11 soil properties, but in no instance were these differences statistically significant. All three soil properties and one soil ion (Ca) were significantly different across the four stands of native vegetation. For the seven soil microelements, significantly different values were detected for Co and Ni, but only among stands of the four invasive plant species. These results indicate that the four invasive plant species altered soil properties, ions, and microelements, but for most of the parameters we assessed, not significantly. Our results do not support our initial prediction, but are in general agreement with previous published findings, which indicate that the effects of invasive plants on soil dynamics vary idiosyncratically among invasive species and among invaded habitats. Full article

Hydrocharis laevigata (Humb. & Bonpl. ex Willd.) Byng & Christenh. [= Limnobium laevigatum (Humb. & Bonpl. ex Willd.) Heine], Hydrocharitaceae, is a floating-leaf aquatic plant that is native to inland South America. It is an invasive species in several parts of the world. Reports of its presence in Europe have been recently published: naturalised populations occur in three locations on the Iberian Peninsula. The literature also contains records of the species in Hungary and Poland. In addition, it has been observed in Sweden, Belgium, and the Netherlands. H. laevigata is highly adaptable and can profoundly transform habitat conditions in its invasive range, causing major issues for ecosystem conservation and human activities. Until recently, H. laevigata was not to be found in natural environments in Europe. Factors explaining its spread include its use as an ornamental plant, the eutrophication of inland waters, and the effects of global warming. With a focus on Europe, this short communication provides information on the species’ distribution, taxonomy, biology, habitat, and negative impacts. Full article

Aeolesthes sarta (Solsky 1871) (Coleoptera: Cerambycidae) is a polyphagous longhorned beetle species that primarily damages broadleaved tree species. This pest is distributed in the western and northern regions of Pakistan, where it caused serious damage to Populus spp. plantations. However, the growth and dispersal patterns of insects and pests are changing due to climate change. Modeling the range expansion or contraction of A. sarta development regions in Pakistan was the goal of the current study, assuming climate change might influence the geographical distribution of A. sarta in Pakistan. Under historical and future climatic conditions, A. sarta distribution areas were estimated using the CLIMEX model. Three time periods, 2030 (early century), 2070 (late century), and 2100 (end century), were forecasted for habitat suitability using the two climate change scenarios (CCSs) A1B and A2. Under the historic climatic condition (HCC), A. sarta was distributed in most areas of Pakistan, and its optimum habitat accounted for 71.67% of its total potential distribution. In the early-century period, optimum habitat dropped to 50.60% and 52.22% under A1B and A2 scenarios in the suitable condition. In the late-century period, optimum habitat further reduced to 31.76% and 30.60% under A1B and A2 scenarios. Moreover, at the end-century period, severe range shrinkage was predicted in the optimum habitat (19.99% under both CSSs). The model predicted a shift in the suitable habitat areas for A. sarta to the west and north. Furthermore, most climatically suitable areas under historic conditions became unsuitable during the end-century period. These projected results will assist in identifying the impacts of global warming on the possible distribution of A. sarta, thereby offering vital information for developing early forecasting and pest-prevention techniques to prevent further loss of forest and woodland trees. Full article

Invasive alien plants have rapidly established and spread in nature reserves via roads and now pose a threat to biodiversity. To understand the mechanism and distribution patterns of invasive alien herbs, we compared the altitude patterns of native and invasive alien herbs based on 105 plots in the Dayao Mountain National Nature Reserve. This study also compared the distribution patterns of new (introduced to China after 1900) and old (introduced to China before 1900) invasive alien herbs. In addition, we examined the effects of climatic factors and human activities on the distribution patterns of species richness. In our study, 151 native herbs species and 18 invasive alien herbs species were observed, of which 12 were new invasive alien herbs. Old invasive alien herbs occurred more frequently and occupied a wider range of altitudes than new invasive alien herbs. The richness of native herbs tended to decrease with increasing altitude, and the altitude patterns of the richness of all invasive herbs and new invasive alien herbs were hump-shaped. Based on an analysis using the linear mixed model, the results indicated that temperature was the main factor limiting the altitude patterns of native herbs, and that temperature and human activities were essential factors in the distribution and spread of all invasive alien herbs and new invasive alien herbs. The intensity of human interference is a crucial driver of the spread of new invasive alien herbs to higher altitudes. Full article

Fragmentation is one of the major threats to biodiversity. In a fragmented landscape, forest specialists are losing suitable forest habitats with specific site and microclimate conditions, which results in their local extinction. Conversely, the invasion of alien species is facilitated by open forest areas and increased boundaries between forest fragments and adjacent land. We studied the effect of fragmentation in terms of fragment size impact on overall plant species richness and on selected ecologically important groups’ richness, composition, and diversity. We surveyed vegetation in the interior of 47 fragments of various sizes and one unfragmented reference forest. Our results reveal that the effect of fragmentation is complex and differs for studied plant groups. Decreasing fragment size negatively affects the overall plant richness and richness of native and ancient forest indicator plants as well as their diversity, while the effect is positive for alien plants. The highest proportion of ancient forest indicator plant species and the lowest proportion of alien plants in the unfragmented forest underline the great conservation value of forest fragments. At the same time, our results reveal that large and diverse forest ecosystems are susceptible to biological invasions as well. Full article

Plant community assembly is the central issue in community ecology. As plant traits differ in different life history stages, the form, intensity and mechanism of interspecific interactions may change with the ontogenetic process of plants. However, our understanding of interspecific interaction mechanisms during germination is still limited. Here, we conducted a laboratory germination experiment using five dominant species in Chongming Dongtan (Spartina alterniflora, Scirpus mariqueter, Phragmites australis, Suaeda glauca and Tripolium vulgare) to assess their germination performance in control (monoculture), allelopathy and mixture treatments. The results indicated that seeds could affect germination performance of neighbors through both allelopathy and salinity modification. Salinity of the solution in Petri dishes after seed germination decreased significantly in most species combinations in competition treatment, and was negatively correlated with the number of total germinated seeds. Seed leachate of invasive Spartina alterniflora significantly accelerated the germination of two native halophytes Suaeda glauca and Tripolium vulgare, but not Scirpus mariqueter and Phragmites australis. The salt absorption by Spartina alterniflora seeds had inconsistent effects compared with that of its seed leachate. On the other hand, seed leachate of native Scirpus mariqueter and Phragmites australis significantly slowed down the germination of invasive Spartina alterniflora. The effect of salinity modification of Scirpus mariqueter on Spartina alterniflora was positive, whereas that of other species was neutral. Considering seed-to-seed interactions is an important perspective to understand the underlying mechanisms of community dynamics, species diversity maintenance and invasion of alien species, and can improve the effectiveness in the management of invaded coastal wetlands. Full article

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. Full article

Plant diversity in relatively harsh environments, such as metal-polluted areas tends to be relatively low. Invasive plants may invade harsh environments more easily than native plants. However, studies often find fewer invasive species in stressful edaphic habitats (such as serpentine soils). Those examples may represent relatively extreme conditions. Moderately stressful habitats may be more invaded given the advantages of invasive plants. We surveyed the plant diversity in four site pairs across three seasons. Sites consist of abandoned mines and reference sites. The mine sites have calcareous soils with relatively high iron, basic pH, and lower nutrients than reference sites. Results: There were 153 plant species among the four site pairs. Around 80 and 66% of species in calcareous and reference sites were introduced species respectively. Diversity varied across seasons but tended to be lower in the mine sites. One of the mines was significantly more invaded. Across sites, the number of invasive species and their abundances was not different from that of native species. Invasive plants are as capable of invading moderately stressful calcareous sites as native species, with some sites tending to be even more invaded. Full article

Invasive alien plants (IAPs) are considered to be one of the greatest threats to global biodiversity and ecosystems. Timely and accurate detection technology is needed to identify these invasive plants, helping to mitigate the damage to farmland, fruit trees and woodland. Hyperspectral technology has the potential to identify similar species. However, the challenge remains to simultaneously identify multiple invasive alien plants with similar colors based on image data. The spectral images were collected by a hyperspectral camera with a spectral range of 450–998 nm, and the raw spectra were extracted by Cubert software. First derivative (FD), Savitzky-Golay (SG) smoothing and standard normal variate (SNV) were used to preprocess the raw spectral data, respectively. Then, on the basis of preprocessing, principal component analysis (PCA) and ant colony optimization (ACO) were used for feature dimensionality reduction, and the reduced features were used as input variables for later modeling. Finally, a combination of both dimensionality reduction and non-dimensionality reduction is used for identification using support vector machines (SVM) and random forests (RF). In order to determine the optimal recognition model, a total of 18 combinations of different preprocessing methods, dimensionality reduction methods and classifiers were tested. The results showed that a combination of SG smoothing and SVM achieved a total accuracy (A) of 89.36%, an average accuracy (AA) of 89.39% and an average precision (AP) of 89.54% with a test time of 0.2639 s. In contrast, the combination of SG smoothing, the ACO, and SVM resulted in weaker performance in terms of A (86.76%), AA (86.99%) and AP (87.22%), but with less test time (0.0567 s). The SG-SVM and SG-ACO-SVM models should be selected considering accuracy and time cost, respectively, for recognition of the seven IAPs and background in the wild. Full article