A review on invasive false indigo bush (Amorpha fruticosa L.): Nuisance plant with multiple benefits

Abstract Increased mobility of people around the globe has facilitated transferring species to new environments, where some have found suitable conditions and even become invasive. False indigo‐bush (Amorpha fruticosa L.) is a plant native to North America but has intentionally or unintentionally spread over the Northern Hemisphere, where it often becomes invasive. The plant is especially easily dispersed within the watersheds of large rivers, where seasonal flooding is regular. Seeds and other propagules are buoyant, and when the water recedes, new plants emerge, forming dense thickets where only a few other species can co‐exist. In order to sustain native biodiversity, spread control is needed. However, mechanical control and eradication measures currently in use are labor demanding and costly, while application of herbicides is limited. On the other hand, the plant possesses a number of beneficial properties, such as phytochemical applications (medical and insecticidal effects), biocoenotic uses (honey plant, ornamental features), and ecosystem services (soil stabilization, provision of food for animals, and fiber and biomass for industry, e.g., nanocellulose). For the reasons above mentioned, the plant is considered quite controversial, and the paper discusses both aspects: potential detrimental effects when introduced to new habitats and its beneficial uses for human society. In addition, the paper presents alternative measures of spreading control (e.g., grazing) and argues that exploiting it for beneficial purposes might help spread control, thus covering the expenses of controlling its distribution.


| INTRODUC TI ON
Invasive species are characterized by fast spreading due to producing numerous offsprings, which can be dispersed from their mother plants at large distances (Richardson et al., 2000). They have a high survival rate due to high tolerance/plasticity in response to a variety of environmental conditions. In the case of plant species and depending on the type of propagation, natural pathways can induce and accelerate spreading, especially in dramatic events such as natural disasters (floods, winds, surface erosion, etc.). Moreover, the spreading of invasive species has been significantly influenced by humans. Historically, after huge geographic discoveries, exotic plants were brought unintentionally or intentionally into new environments and cultivated as gardening plants or ornamental plants. People's increased mobility has further promoted spreading by connecting geographically distant regions (Miyawaki & Washitani, 2004) and erasing natural barriers. Subsequently, if an invasive species reaches new habitat, its ability to adapt to new conditions, coupled with biotic and abiotic factors of the host habitat, will determine its further fate in terms of survival and reproduction (Blackburn et al., 2011;Lodge, 1993). In addition, from the moment of introduction to a new environment until becoming invasive, a species has to endure and overcome different points in the invasion process defined by the unified framework proposed by Blackburn et al. (2011). Depending on the ability of a species, some were naturalized and successfully spread in the wild. Occasionally, the spreading of alien species is facilitated by coupled actions of humans and environmental properties of new habitats. There is a twofold role of human activitiestransporting propagation material and altering habitats. Transport of propagation material can be intentional and unintentional. The success of invading new habitats is predominantly affected by the similarity to their natural habitats (abiotic factors), the competitive strength of native species, while anthropogenically modified habitats facilitate the spreading of nonnative species, leading to biodiversity loss and the disruption of local ecosystems and ecosystem functions (SCBD, 2006).
False indigo bush (Amorpha fruticosa L.), shown in Figure 1, represents a good example of an invasive plant to which all aforementioned spreading pathways can be applied. Therefore, its successful spreading from North America across most parts of the Northern Hemisphere has taken place for a few centuries. Intentional spreading of the species by humans indicates that it possesses some attributes for which it has been considered beneficial. In the case of A. fruticosa, there is a wide range of uses, and each organ from fruits and flowers down to its roots has some use-value. It has potential for medicinal, food, and industrial applications (Ciuvăţ et al., 2016;DeHaan et al., 2006;Hovanet et al., 2015;Krpan et al., 2014;Zhuo et al., 2017). The above facts, that is, its invasive character and the fact that it can be exploited for various purposes, make A. fruticosa L. quite controversial.
Our intention is to provide an extensive overview of A. fruticosa's history of spreading, reproductive morphology, and preferences toward the abiotic and biotic surroundings. In addition, given its controversial nature, we have examined spread control measures and listed possible uses to offer comprehensive and viable solutions for managing A. fruticosa in areas where it represents a threat and nuisance.

| IN CRE A S ING RE S E ARCH AT TENTI ON FO R A . FRUTICOSA
Data about A. fruticosa, concerning the species origin and distribution, habitats, and adverse and beneficial effects considering its ecology, allelopathic effects, medical, and other uses, were derived from scientific publications using services such as Web of Science-WOS, PubMed, Google Scholar, and ScienceDirect. In addition, relevant databases such as Global Biodiversity Information Facility (GBIF, 2021), Centre for Agriculture and Bioscience International (CABI, 2020), and European and Mediterranean Plant Protection Organization (EPPO) (2021) were also valuable sources of references and distribution maps. In this review, we have shown separately results for each repository. We have focused only on the number of publications during the time per repository, simultaneously avoiding debate on possible duplications, their sources, or methods for data processing. The search of major repositories and academic search engines upon using "amorpha fruticosa" as a keyword revealed the following numbers of publications: ScienceDirect-417, Scopus-369, WOS-226, PubMed-97 and Google Scholar around 13.700. There is an evident increase in publication number in ScienceDirect, followed by WOS and PubMed, particularly in the second decade of the 21st century after being at a low level of <10 publications per year since the 1990s, indicating that it is a vivid field of investigation ( Figure 2). Moreover, our goal was to emphasize fields in which most publications were published concerning A. fruticosa, that is, to identify F I G U R E 1 Amorpha fruticosa in flowering phase, Obedska Bara Special Nature Reserve, Serbia.
research fields which are in the focus of the scientific community.
Fortunately, ScienceDirect and Scopus provided such a possibility automatically. Therefore, we are presenting results just for these repositories. According to ScienceDirect, the most represented are publications related to agricultural and biological sciences (36%) and environmental sciences (28%), whereas for the same areas by Scopus, the share is 43% and 25%, respectively ( Figure 3). In addition, publications in other categories are represented by less than 10%, for example, in biochemistry, genetics and molecular biology; Earth and planetary sciences, as well as in chemistry; pharmacology, toxicology, and pharmaceutics; social sciences; energy (Figure 3a).
The general conclusion that can be drawn from the representation of publications by research fields (Figure 2) implies that investigating A. fruticosa from the ecological and environmental perspective presently dominates over research related to its molecular and phytochemical nature. Therefore, this paper provides a comprehensive review encompassing A. fruticosa distribution, biology, and ecology, including invasiveness and control/management. Nevertheless, beneficial uses are also included since its valuation may help in spread control.

| ORIG IN AND DIS TRIBUTION
Amorpha fruticosa is native to North America. Its native range extends from southern Canada to northern Mexico, west to California, and east to Florida (Gleason & Cronquist, 1991;Ulrich & Zaspel, 2000).
In several states of the United States, it is regarded as a noxious weed (DiTomaso et al., 2013;Glad & Halse, 1992). Native range and its present distribution are shown in map ( Figure 4).
The first records on its introduction to Europe date back to 1724 when it was brought as an ornamental plant to England (Karmyzova, 2014). Afterward, it used to be widely planted in Europe at the beginning of the 20th century and was introduced in North Asia before the middle of the same century (Jung, 2014;Takagi & Hioki, 2013;Ulrich & Zaspel, 2000;USDA-ARS, 2021). Presently A.
fruticosa is reported to be invasive in a number of European countries (EPPO, 2021;Roy et al., 2020). In Europe, it has been cultivated for its ornamental features (Cullen, 1995) and as a honey plant. In addition, due to its protective properties against soil erosion, it has been intentionally dispersed along freshly built canals to stabilize embankments, especially in some regions of southeast Europe, where later it has become naturalized. The first written data on the presence of A. fruticosa in southeast Europe, for example, in Hungary and Bulgaria, dates back to the 1920s and 1930s (Pedashenko et al., 2012;Szentesi, 1999;Szigetvári & Toth, 2008). Presently in this region, it has been recognized among the most invasive species, and spread control is urgently needed (Doroftei et al., 2005;Gudžinskas & Žalneravičius, 2015;Körmöczi, 2012;Kozuharova et al., 2017;Kucsicsa et al., 2018). Gudžinskas and Žalneravičius (2015) reported that A. fruticosa was first found in 2015 in Lithuania as naturalized and potentially invasive, and the same can be assumed for Central Russia (EPPO, 2021). In addition, in the south of the Russian Far East, it has been present in botanical gardens and landscape design F I G U R E 2 Number of publications on Amorpha fruticosa deposited in PubMed, WOS, and ScienceDirect, for period 1990-2020. of urban and suburban areas . In China, A. fruticosa is a common shrub of its temperate regions widely planted as a windbreaker (Liu et al., 2005) and intentionally spread on Loess Plateau to stabilize soil (Yan et al., 2017) across the Delta of the Yellow River (Guo et al., 2018). In Japan, A. fruticosa was introduced from the eastern part of North and Central America to revegetate artificial slopes. However, it has later spread out to watersheds of rivers Hokkaido, Honshu, Shikoku, Kyusyu, and Okinawa (Hioki et al., 2015), posing now a significant threat to the local biodiversity.
In the future, its ornamental value might be the reason for further spreading to the rest of Asia and also potentially to other continents, such as Africa and Central America (CABI, 2020).
Global databases such as EPPO, CABI, and GBIF can give insight into present distribution, but also the history of spreading. For example, the GBIF database presently stores more than 16,000 records, of which for more than 8000, the exact location is provided, accompanied by the date of observation. Using geo-positioned data, we have produced maps showing the distribution of A. fruticosa for certain periods from its first records until the present day ( Figure 5). It is evident from the map (Figure 5a) that in the second half of the 19th and the first half of the 20th century, the species has been brought to new habitats considerably remote from its native ones. This includes Europe, Asia, and the Far East, but also spreading across the North American continent. And concerning its native range, there is an obvious lack of georeferenced data for A. fruticosa for the period 1727-

| Reproductive biology
Amorpha fruticosa is a fast-growing shrub, which reproduces sexually-by producing a large number of seeds. Pollination is performed by insects, mainly bees, belonging to the genus Andrena F I G U R E 3 Representation of publications on Amorpha fruticosa concerning research area according to: (a) ScienceDirect and (b) Scopus. (CABI, 2020;Halbritter & Heigl, 2021), and also by Apis mellifera L.
Pollen is small (10-25 μm), isopolar, oblate, with three colporous aperture (CABI, 2020;Halbritter & Heigl, 2021). Apart from sexual reproduction, it can also proliferate vegetatively (asexuate) by sprouting, and stems can root at the nodes (Szigetvári, 2002), generating spindles from its superficial roots. These spindles can be very well-developed and ramify widely (Harold et al., 2005). In response to flooding events, A. fruticosa forms adventitious roots (Kozlowski, 1997). It is considered to be a facultative halophyte and tolerates medium saline soils, since germination is inhibited at 3000 mg/L NaCl, while reduced values of germination parameters were recorded at concentrations of 700 and 1400 mg/L of NaCl (Đukić et al., 2010). One of the reasons might be that rhizobial strains isolated from A. fruticosa were not tolerant to salt concentrations above 1% NaCl (Ulrich & Zaspel, 2000).
In alluvial soils near rivers, almost 2/3 of the species' seeds stay in the upper soil layer up to 10 cm, while almost 1/3 can be found in the 10-20 cm soil layer (Blagojević et al., 2015). The same research revealed that a soil layer of 0-30 cm contained 3270 seeds/m 2 , with a germination percentage of 3.73%, that is, the number of potential plants was 122 plants/m 2 . The spreading of A. fruticosa is facilitated by its seed pods being buoyant and spreadable by water (Blagojević et al., 2015;Szigetvári, 2002). In addition, birds and small mammals are also reported to feed on seeds, for example, specimens of Parus sp. consume A. fruticosa seeds, which might also help the species' propagation (Doroftei et al., 2005).

| Habitat
Amorpha fruticosa grows in a wide range of habitats, including riparian and alluvial habitats, sandy banks of ravines, coastal areas, dunes, and disturbed land, such as plantations, orchards, meadows, urban areas, and fishing pond depressions (Botta-Dukát, 2008;Doroftei et al., 2005;Dumitrascu et al., 2013;EPPO, 2021;Karmyzova, 2014;Szigetvári, 2002). It often can be found on wet habitats dominated by Salix alba and Populus alba galleries, riparian galleries and thickets, alluvial forests with, riparian mixed forests, and along the great rivers (Dumitrascu et al., 2013;EPPO, 2021). The species can be rarely found on the edges of water bodies that are constantly wet (Pedashenko et al., 2012), since it does not tolerate constantly wet conditions, but only temporary during flooding periods. It is taught to be weak competitor in forests, usually suppressed by tree species (Szigetvári, 2002). However, according to our observations in Special Nature Reserve Obedska Bara, Serbia, it dominates bush layer in mixed forest of English oak (Quercus robur L.), manna ash (Fraxinus ornus L.), black poplar (Populus nigra L.), and common hornbeam (Carpinus betulus L.), whereas on meadows and pastures, it absolutely predominates in a few years. It succeeds thanks to a number of its attributes, that is, fast growth, shading competitors, its nitrogen-fixing ability (Boscutti et al., 2020), and suppressing allelopathic effects (Csiszár, 2009;Xiao et al., 2016). Its ability to inhibit the germination and growth of other plant species by the release of allelopathic substances was confirmed by Csiszár (2009) andCsiszár et al. (2013) who found out that the juglone index for A. fruticosa was near 1 for lower extract concentration or 2 for higher extract concentration, while Xiao et al. (2016) proved inhibition in growth of some medical plants planted in the humus soil of A. fruticosa. This may suggest that allelopathic effects could contribute to the overall success of the invasion process. Expansion of A. fruticosa not only contributes to biodiversity decrease but might also lead to the formation of almost impenetrable stands together with other vine or shrub species (e.g., Echinocystis lobata, Robinia pseudoacacia, Prunus F I G U R E 4 Native distribution of Amorpha fruticosa and its present range within the North American continent. spinosa, Rosa canina, and Rubus sp.) (Glišić et al., 2014;Sándor & Kiss, 2008).
The species prefers a warm temperate climate with dry summer or dry winter, or wet all year, and continental climate with dry summer, or wet all year (CABI, 2020) (Table 1). Concerning low temperatures, it seems that the number of frosty days influences seed germination (Doroftei et al., 2005). Amorpha fruticosa inhabits soils of acid, alkaline or neutral chemical reaction, and light or medium soils texture (CABI, 2020). It grows in well-drained soils, medium to wet. Although it prefers to grow along watercourses, it can tolerate dry soils and occasional flooding. Its well-developed root system enables it to be relatively wind-tolerant (Doroftei et al., 2005;Kozuharova et al., 2017). The species prefers to grow at sites with high illumination (Takagi & Hioki, 2013), but it also tolerates partial shade (Doroftei et al., 2005). Regarding pH, A. fruticosa studied in the Danube Delta was tolerant to a pH range of 5.8-7.6 (Doroftei et al., 2005), while according to other sources, the range it tolerates is wider, that is, 5.0-8.5 (Harold et al., 2005; USDA, 2019).

| Ecology
Belonging to the order Fabales, A. fruticosa establishes mutual relationships with symbiotic bacteria, which enable capturing and binding atmospheric nitrogen, thus promoting plant growth and contributing to soil fertility. Research on rhizobial strains nodulating A. fruticosa compared to other legumes confirmed that A. fruticosa as a neophytic plant could form nodules with several phylogenetically different rhizobia. This might be an important attribute for adapting to new habitats compared to archaeophytic plants, which are specialized and host only one or a few specific microsymbionts (Ulrich & Zaspel, 2000).
Branches and leaves of A. fruticosa are dense, clustered, fastgrowing, and closed early, leading to relatively fast ground covering (Yin, 1993). This characteristic can be assumed as positive from the aspect of A. fruticosa since the plants get relatively resistant to environmental conditions. However, from the point of view of other plant species forming native vegetation, dense growth, and abundant shade inhibit the growth of other native, where especially herbaceous plants are susceptible. It provides food not only to bees but also to some other insects such as Zerene cesonia (CABI, 2020).
Moreover, a few bird species of order Passeriformes were found within a canopy of A. fruticosa (Doroftei et al., 2005).
The species well tolerates waterlogged stress (Wang et al., 2012) and can grow in temporary wet conditions. It is considered to be facultative halophyte, since germination is inhibited at 3000 mg/L of NaCl, while reduced values of germination parameters were recorded at concentrations of 700 and 1400 mg/L of NaCl (Đukić et al., 2010).

| INVA S IVENE SS OF A . FRUTICOSA
It seems that A. fruticosa does not represent a threat in terms of invasiveness within its natural habitats. For example, according to Hupp and Osterkamp (1996), A. fruticosa contributes to forming riparian vegetation of the Plum Creek, Colorado (USA). There, it has been listed in 6th place (out of 8), by importance, of common woody species. However, it has been introduced in to the states of New England and Washington, but it was recognized as a noxious weed, that is, Connecticut (USDA, 2019) and Washington (WS NWCB, 2022).
Concerning invasiveness, A. fruticosa is now generally recognized as one of Europe's most invasive alien species ( Figure 5). It has a high reproductive capacity, forms dense thickets and outcompetes native flora, changing successional patterns, and reducing biodiversity (CABI, 2020;Cronk & Fuller, 2001;Glišić et al., 2014). The main natural factor contributing to invasions is flooding which facilitates the dispersal of seeds and other propagation material by water (Pyšek & Prach, 1994). Another argument is the fact that river corridors are characterized by longitudinal continuity, as recognized in the river continuum concept (Rood et al., 2010). Therefore, habitats with wet and mesic conditions are more susceptible to invasions than dry ones (Botta-Dukát, 2008). In addition, the Danube watershed's dense hydrological network and favorable continental climate facilitated the spreading of its water-dispersed propagules (Pedashenko et al., 2012;Pyšek & Prach, 1994).
In Europe, during the past two decades, a significant presence of A. fruticosa causing nuisance has been reported in Hungary, Bulgaria, and Romania Szigetvári, 2002). In other southeast European countries, for example, Croatia, Slovenia, and Serbia the species is recognized as highly invasive within the Sava River Basin (Blagojević et al., 2015;Kus Veenvliet, 2021). The main factors responsible for the introduction and spreading of A. fruticosa are presented in Figure 6. Generally, it can be concluded that A. fruticosa is an important invasive species in Europe (CABI, 2020;Roy et al., 2020) and Asia (CABI, 2020).

| Impact on habitats and biodiversity
A nonnative species in new forest habitats may have profound and cascading effects, reflected in various aspects, starting from modifying tree species composition to changes in nutrient, carbon, and water cycle (Boscutti et al., 2020;Liebhold et al., 2017;Pellegrini et al., 2021). Additionally, A. fruticosa has especially a pronounced impact in soil enrichment by N due to nitrogen-fixing ability. The mentioned property causes alterations in the N cycle, which leads to cascading effect on other soil functions, eventually decreasing the biodiversity of native vegetation (Boscutti et al., 2020). This assumption can be applied to A. fruticosa, which is considered not just TA B L E 1 Climate that A. fruticosa L. prefers (CABI, 2020;Peel et al., 2007) (Peel et al., 2007).
as invasive species, but rather a transformer species that invades disturbed areas (Kozuharova et al., 2017;Protopopova et al., 2006;Szigetvári, 2002). Due to its nitrogen-fixing ability, A. fruticosa enriches the soil with nitrogen and substantially changes its content, thus making less favorable conditions for native flora. Therefore, it is characterized as a transformer species (Pellegrini et al., 2021). In addition, its outstanding characteristics, such as rapid growth, fast closing, and formation of dense thickets, contribute to its ability to outcompete native flora. All the mentioned properties lead to native habitat fragmentation and loss, deteriorating ecosystem structure and functioning, changing successional patterns, and finally reflecting on overall biodiversity decrease (Cronk & Fuller, 2001;De Poorter et al., 2007;Kucsicsa et al., 2018;Sărăţeanu, 2010). Despite the mentioned impacts, not all regions and vegetation types are affected by the same intensity (Vitousek et al., 1997). fruticosa (Csiszár, 2009). In addition, habitat alterations made by A.
fruticosa overgrowth significantly influence the composition of soil invertebrates, which are not directly related to the plant but could be instead attributed to microclimatic conditions of changed habitats (Brigić et al., 2014 (Szigetvári, 2002). Mechanical control is the primary means of control within protected areas since the application of chemicals is prohibited (Ciuvăţ et al., 2016). In man-made habitats such as in poplar plantations, agrochemical measures are permitted. Regular management usually assumes

F I G U R E 6
The main natural and human induced factors responsible for the introduction and spreading of Amorpha fruticosa and final outcomes (within the intersection).
replanting, but with previous soil plowing and removing old logs.
During the procedure, root fragmentation occurs, which contributes to plant survival and propagation (Pedashenko et al., 2012).
In such cases, if eradication is the goal, chemical control must be employed.  (Kozuharova et al., 2017).
Another side of the problem lies in changes in land use.
Abandoning traditional extensive human disturbance regime, such as mowing and grazing, pastures and meadows have transformed into gallery forests due to natural succession. The absence of these actions contributes to and facilitates A. fruticosa colonizing the meadow communities, leading to the formation of dense homogenous thickets within 5-6 years (Kóra, 2002), or even faster 4-5 years (Pellegrini et al., 2021). This process results in a significant biodiversity decrease, where only rare meadow plant species can survive and compete under the closed canopy of A. fruticosa (Kóra, 2002;Zavagno & D'Auria, 2001).
As a precaution, if A. fruticosa is intentionally introduced for commercial or environmental purposes, control measures must be first tested on a pilot area to select the best measure before planting on vast areas (Hioki et al., 2015). Bearing in mind that A. fruticosa is mainly spread by water; it can be assumed that dams and reservoirs may prevent the downstream spreading of an invasive species.
Furthermore, such man-made structures lead to fragmentation of the river corridor and impede the transfer of invasive species propagules, thus providing an environmental benefit (Rood et al., 2010).

| Beneficial uses of A. fruticosa
During the centuries, the species has been used traditionally for forage, woody biomass, indigenous medicine etc. Still, lately, its applications have been diversified, and sophisticated technologies were applied for some uses, for example, for research in the field of medicine or for obtaining nanocellulose (Figure 7) Therefore, A. fruticosa is used for stimulating immunity, treating diabetes, metabolic disease, and cancer (Cvetković et al., 2019;Kozuharova et al., 2017;Lee et al., 2006;Lee et al., 2016), as well as possessing antimicrobial properties and for treating stomach pain, intestinal worms, eczema, neuralgia, carbuncle, burns, wounds, and rheumatism. In search for possible antitumor agents, Li et al. (1993) extracted 8 novel cytotoxic compounds, belonging to rotenoids and isoflavones. Furthermore, Muharini et al. (2017) found 14 new natural compounds, together with 40 already known isolated from the fruits of A. fruticosa, and tested them for their antimicrobial activity. Some compounds showed potent to moderate antibacterial activities against several Gram-positive bacteria. The same research confirmed that some natural compounds derived from fruits of A. fruticosa were significantly cytotoxic against the mouse lymphoma cell line. In Table 2 are summarized medical properties of the plant, concerning traditional use and new applications in medicine.
Additionally, an extensive review of A. fruticosa medical properties is given by Kozuharova et al. (2017).
Another potential beneficial use is in obtaining insecticidal formulations. Historically, already during the first half of the 20th century, Brett (1946)

investigated A. fruticosa for its insecticidal
properties. Tests on 29 species of insects and mites showed that the extract acted as a stomach and contact poison for tested species. In addition, it showed repellent ability to house and horn flies for more than 12 h when sprayed on cattle. The most susceptible to it were chinch bugs, cotton aphids, pea aphids, chrysanthemum aphids, and spotted cucumber beetles. According to research by Qu et al. (1998), 4 active compounds from leaves of A. fruticosa were isolated: (1) 6alpha, 12alpha-dehydro-alpha-toxicorol, (2) 6alpha, 12alphadehydro-deguelin, (3) (±)-tephrosin, and (4) (−)-6-hydroxy-6alpha.

Leaf
Retenoids have shown significant anti-tumor effect on mouse skin tumor Konoshima et al. (1993) Stimulating immunity Fruit Stimulating growth of human T cells Lee et al. (2006) Antimicrobial Fruit, leaf, root Positive antimicrobial effect on certain Gram positive and Gram negative bacteria Mitscher et al. (1981), Hovanet et al. (2015), Muharini et al. (2017), Kim et al. (2011) nanocellulose could be further applied in various domains like electronics, biomedicine, and aerospace.

| Biocoenotic uses and ecosystem properties
It has already been elaborated that A. fruticosa can have a suppressive effect on native biodiversity due to its ability to reproduce and adapt successfully. Nevertheless, its reproduction is facilitated by pollinators which are in turn attracted by numerous inflorescences rich in pollen and nectar. Amorpha fruticosa represents an important food source for bees and other insects within its native and new habitats where it has been introduced (Kozuharova et al., 2017). Therefore, it is regarded as a significant honey plant from the point of ecosystems and beekeepers (Li et al., 2014;Stefanic et al., 2004). In addition, since the 18th century, A. fruticosa has been considered a valuable decorative plant (Cullen, 1995). Its growth, phenology, adaptability, and resistance make the plant suitable for different types of urban green spaces and gardens in China. Above all, it is considered a water-saving plant suitable for planting in urban areas with water shortages, such as in Beijing (Huang, 2005).

| Ecosystem services A. fruticosa provides
One of the most frequently used ecosystem services is the A. fruticosa's ability to stabilize soil on slopes. It has been widely used in forestry, preventing soil erosion, and reclamation of degraded environments (DeHaan et al., 2006;Yin, 1993). There are two ways by which A.
fruticosa can contribute to preventing soil erosion (Yin, 1993): (1) it is fast-growing and establishes a closed canopy in a short time, covering the ground quickly and thus intercepting rainfall and preventing soil erosion, and (2) mature A. fruticosa stands produe yearly a large amount of dead plant material thus protecting soil surface from splashing erosion. Therefore, the species has been considered as an ideal tree species for protecting forests at gully head and fixing the bank and cliff of slope embankment, soil consolidation, slope protection, ditch protection, as well as on railway embankments, and soil and water conservation (Kozuharova et al., 2017;Yin, 1993). In addition, it is also considered as suitable for revegetation of moderately saline soils (Đukić et al., 2010;Guo et al., 2018) and for stabilizing metals from Pb to Zn mine tailings (Sikdar et al., 2020), opening a new possibility for its application-phytomining.
Amorpha fruticosa expresses negative allelopathic effect toward some plant species (Xiao et al., 2016), while stimulating some others . Interestingly, the growth of another invasive plant Phytolacca americana could be controlled at the sites where A.
fruticosa was in vigorous growth (Fu et al., 2012). Besides, there are positive examples where A. fruticosa has been used as intercropping plant (Lygis et al., 2004), and possibilities to use it as for forage and biomass (DeHaan et al., 2006).  (Demeter et al., 2021) and even helping manage poplar and other soft-wood plantations. Therefore, this management option is truly multifunctional leading a "win-win-win" scenario (Demeter et al., 2021). On the contrary, in an area where a lower level of invasion is recorded, control of invading species is desirable and achievable. Nevertheless, the management of an invasive species is quite complex and it requires transdisciplinary endeavors (Richardson et al., 2014). This is especially necessary when a species shows dualistic nature-negative toward the environment and simultaneously satisfying human needs. Such challenging tasks require multidimensional evaluation including an interdisciplinary team which takes into consideration ethics, law, policy, ecology, and natural resources management (Schwartz et al., 2012), leading to the development of pragmatic solutions and innovative approaches to conflict resolution (Hobbs et al., 2013;Richardson et al., 2014).

| CON CLUS ION
The plant species A. fruticosa is quite controversial. In areas where it has been intentionally spread, especially for soil stabilization along canals, it represents a real threat to native biodiversity. There are a variety of measures that have proven to be effective for its spread control (mechanical, chemical, and biological, or alternating their TA B L E 3 Usage summary of A. fruticosa, apart from medical purposes

Seeds
Insecticidal-amorhinogenin to larvae of the mosquito Culex pipiens pallens (Diptera: Culicidae) Liang et al. (2015) Insecticidal, repellent Brett (1946), Qu et al. (1998) Fruit Amorfrutins used as an ingredient in some condiments Kozuharova et al. (2017) Branches Weaving of baskets and fences Traditional use Whole plant/roots Forestry-soil stabilization, erosion prevention, windbreak, shelterbelt Yin (1993)  However, in historically heavily affected regions a win-win scenario would be promoting its use for beneficial purposes, thus achieving speeding control in a cost-effective and sustainable manner.
Future perspectives may be oriented in two directions: investigation of proper integrated management strategies on spreading control, adequate for certain regions, and further exploration of beneficial effects. In both cases, finding economic value for A. fruticosa uses may help. Therefore, smart management in invaded areas based on its controlled exploitation for beneficial purposes could be a leading strategy in future A. fruticosa spreading control.

ACK N OWLED G M ENTS
This work was supported by the Ministry of Education, Science and Technological Development of the Republic of Serbia (Grant No. 451-03-9/2021-14/200117).

CO N FLI C T O F I NTE R E S T
None declared.