Spontaneous Plants Research Articles

Phytoremediation potential depends on the degree of soil pollution: a case study in an urban brownfield

Phytoremediation is a cost-effective nature-based solution for brownfield reclamation. The choice of phytoextraction or phytostabilization strategies is highly relevant when planning full-scale treatments. A suitable approach to identify such species involves the evaluation of plants that grow spontaneously on the contaminated sites. Here, we sought to determine the phytoremediation potential of three spontaneous plant species, namely the trees Acer pseudoplatanus L (A. pseudoplatanus) and Betula celtiberica Rothm. & Vasc (B. celtiberica), and the shrub Buddleja davidii Franch (B. davidii), for the recovery of an urban brownfield. To determine the response of the species to the degree of contamination, we conducted soil and vegetation sampling inside and outside the site. The concentrations of As, Cu, and Zn in soil and plant samples were measured, and then various indexes related to phytoremediation were calculated. The translocation factor and transfer coefficient indicated that vegetation outside the brownfield had phytoextraction capacity while the same plants inside the brownfield revealed phytostabilization properties. Given our results, we propose that the selected species are suitable for phytostabilization strategies in areas with high concentrations of contaminants, whereas they could be used for phytoextraction only in soils with low or moderate levels of pollution.Graphical

Alpine Diet in Valmalenco (Lombardy, Italy): Nutritional Features of Spontaneous Plants and Traditional Dishes.

Along the Alps, the Alpine diet is considered to be one of the most common nutritional models. Next to traditional animal-based products, spontaneous plants of the territory are collected and eaten. The aim of this study is to evaluate the nutritional features of selected autochthonous plants of the territory and the typical recipe of green gnocchi. The analyses of proximate composition, carotenoid, total phenol, and mineral contents in raw and cooked plant samples and the chemical composition and in vitro starch digestibility in green and control gnocchi were performed. Except for Aruncus dioicus, all the wild plants contained high levels of carotenoids (15-20 mg/100 g FW), mainly as xanthophylls. Rumex acetosa showed the highest levels of total phenols (554 mg GAE/100 g FW), and Urtica dioica can be considered to be a good dietary source of iron, calcium, and magnesium (4.9, 410, and 72 mg/100 g FW). Cooking significantly decreased the potassium and magnesium contents in all wild species, and total phenols and carotenoids in Aruncus dioicus, Blitum bonus-henricus, and Silene vulgaris (p < 0.05). The slowly digestible fraction of starch (%SDS/available starch), which is inversely correlated to insulin demand, was significantly increased in green gnocchi compared to matched control gnocchi (p < 0.05). Traditional consumption of spontaneous plants in the Alpine regions might increase the dietary intakes of several bioactive substances and contribute to cover the nutritional needs of micronutrients.

Microarthropod communities act as functional mediators of ecosystem recovery in abandoned metal(loid) mine tailings in semiarid areas

Abandoned metal(loid) mine tailings show inhospitable conditions for the establishment of above- and below-ground communities (e.g., high metal(loid) levels, organic matter and nutrient deficiency). This worsens in semiarid areas due to the harsh climate conditions. Fertility islands (vegetation patches formed by plants that spontaneously colonize the tailings) can serve as potential nucleation spots fostering beneficial plant-microbial interactions. However, less attention has been paid to the soil invertebrates living beneath these patches and their functional role. Here, we studied whether the spontaneous plant colonization of abandoned metal(loid) mine tailings led to a greater presence of soil microarthropod communities and whether this could contribute to improving ecosystem functionality. Microarthropods were extracted, taxonomically identified and subsequently assigned to different functional groups (saphrophages, omnivores, predators) in bare soils and differently vegetated patches within metalliferous mine tailings and surrounding forests in southeast Spain. Microarthropod communities were significantly different in bare soils compared with vegetated patches in mine tailings and surrounding forests. Plant colonization led to an increase in microarthropod abundance in tailing soils, especially of mites and springtails. Moreover, saprophages and omnivores, but not predators, were favored in vegetated patches. The initial microarthropod colonization was mainly linked to higher organic matter accumulation and greater microbial activity in the vegetated patches within mine tailings. Moreover, soil formation processes already initiated in the tailings were beneficial for soil biota establishment. Thus, below-ground communities created an anchorage point for plant communities by primarily starting heterotrophic activities in the vegetated patches, thereby contributing to recover ecosystem functionality.

Diversity of greenspace design and management impacts pollinator communities in a densely urbanized landscape: the city of Paris, France

The response of insect pollinator communities to increasing urbanization is shaped by landscape and local factors. But what about habitats that are already highly artificial? We investigated the drivers of pollinator diversity in a dense urban matrix, the city of Paris. We monitored insect pollinator communities monthly (March-October) for two consecutive years in 12 green spaces that differed in their management practices, focusing on four insect orders (Hymenoptera, Diptera, Lepidoptera, Coleoptera). Pollinator abundance and species richness were both positively tied to green space size and flowering plant species richness, but negatively linked to surrounding impervious surfaces. In addition, environmental features at both the local and landscape scales influenced the composition and functional diversity of wild bee communities. Indeed, small and large bees responded differently, with the occurrence of large-bodied species being impaired by the proportion of impervious surfaces but strongly enhanced by plant species richness. Also, sites with a majority of spontaneous plant species had more functionally diverse bee communities, with oligolectic species more likely to be found.These results, consistent with the literature, can guide the design and management practices of urban green spaces to promote pollinator diversity and pollination function, even in dense urban environments.

Microbiological properties of soils are sensitive to changes provided by organic cultivation of banana ‘BRS Princesa’ in the semi-arid region

Soil microbiota has a key role in the dynamics of natural and agro-ecosystems and is sensitive to changes in these environments. This study evaluated changes in the microbiological properties of soils under an organic production system of banana ‘BRS Princesa’ (Musa spp.). The experimental design consisted of completely randomized blocks, with four replications. Treatments consisted of 1) soil cover with green manure and agricultural gypsum at a dose of 2,820 kg ha−1, 2) soil cover with green manure without gypsum application, 3) soil cover with weeds and agricultural gypsum at a dose of 2,820 kg ha−1, 4) soil cover with spontaneous plants without gypsum application, and two controls: 5) soil under native Caatinga and 6) soil under regenerating forest (capoeira). The evaluated properties were β-glucosidase, arylsulfatase, acid phosphatase, fluorescein diacetate hydrolysis activities (FDA), carbon and phosphorus contents in microbial biomass, basal soil respiration, microbial and metabolic quotients, and arbuscular mycorrhizal fungi spore density. Soil samples were collected from the 0–0.20m depth layer in two seasons. No parameter could distinguish the treatments. Spontaneous plants provided conditions equivalent to those under green manure. Agricultural gypsum application also did not influence the microbial biomass and microbiota activity, in the analyzed soil depth. However, β-glucosidase and arylsulfatase activities, the carbon content in microbial biomass, and metabolic and microbial quotients were sensitive to land-use changes and could distinguish areas under organic cultivation from those under native vegetation. Therefore, these properties can be considered good indicators for monitoring the quality of these soils. Furthermore, microbial communities of soils under organic cultivation responded with arylsulfatase activity corresponding to that found in soils under regenerating forest, which may indicate that organic management tends to provide the microbiota with a condition similar to that found under situations that are little disturbing to edaphic living.

Functional structure and interactions within communities composed of cover crops and spontaneous species, along a cropping practices gradient

Inclusion of a cover crop is an interesting way to diversify cropping systems and support ecosystem functions and services impaired by intensified monocultures. However, pure covers are hard to obtain without substantial management, and mixed covers—wherein some spontaneous species coexist with sown cover crops—seem to be a good alternative. Greater insight into factors influencing the composition and density of the spontaneous plant community is needed to achieve relatively good control of the performances of this mixed cover. Here we addressed two questions: 1) How does the functional structure of communities with a highly competitive sown cover crop and/or high initial species diversity differ from the functional structure of communities with the opposite characteristics? 2) Can aboveground species traits explain interactions between cover crops and spontaneous species present in the same community? In a fallowed field in Guadeloupe (West French Indies), we studied communities composed of one sown cover crop species and spontaneous species growing simultaneously in the plot. The study was conducted along two unrelated experimentally-devised gradients resulting from cropping practices: a competitivity gradient of a sown cover crop species and an initial species diversity gradient resulting from an initial soil perturbation induced by the false seedbed technique. These factors (soil tillage modality before cover crop sowing and cover crop species identity) were combined in a split-plot design. Seven and twelve months after cover crop sowing, community species densities and biomasses were assessed. Leaf trait values of the 12 most present species were measured at flowering to describe the functional structure of the community using the community weighted trait means and variances, and a functional diversity index. Our results showed high functional divergence in communities with highly competitive cover crops, which suggests differentiation of functional niches between species, but no clear differences in communities with high and low initial species diversity. We also showed that the studied species were positioned along a gradient from acquisitive to conservative strategies of resource capture and use according to their leaf trait values, regardless of their type (cover crops or spontaneous species), and that cover crop species had higher trait values related to size than spontaneous species. Finally, we demonstrated that interactions between cover crops and spontaneous species could be better explained by the cover crop dynamic height or community biomasses than by the measured aboveground functional traits and that the plant growth habit had a central role. This study shed light on interactions between sown cover crops and spontaneous species, which are pivotal to the design of diversified cropping systems.

Driving effects of land use and landscape pattern on different spontaneous plant life forms along urban river corridors in a fast-growing city

River corridors are critical in connecting fragmented greenspace and providing habitats for plants and animals. There is a paucity of information on the detailed influence of land use and landscape patterns on the richness and diversity of distinct life forms of urban spontaneous vegetation. This study aimed to identify the variables that dramatically affect spontaneous plants and then disentangle how to manage such a variety of land types to maximize the biodiversity-supporting function of urban river corridors. The total species richness was remarkably influenced by the amount of commercial, industrial, and waterbody area and the landscape complexity of water, green space, and unused land. In addition, the spontaneous plant assemblages of different life forms significantly differed in their responses to land use and landscape variables. Vines were more sensitive to urban sites, i.e., strongly negatively affected by residential and commercial areas but positively supported by green space and cropland. Multivariate regression trees indicated that the total plant assemblages were clustered most remarkably by the total industrial area, and the classified responding variables differed among distinct life forms. The colonizing habitat of spontaneous plants explained a high proportion of the variance and was also closely related to the surrounding land use and landscape pattern. These scale-specific interaction effects ultimately determined the variation in richness among various spontaneous plant assemblages in urban sites. Based on these results, in future city river planning and design, spontaneous vegetation could be protected and promoted by a nature-based solution according to their adaptability and preference for distinct landscape characteristics and habitat features.

Biology and life table of Tetranychus neocaledonicus André (1933) (Acari: Tetranychidae) in different hosts

Tetranychus neocaledonicus colonizes both cultivated and spontaneous plants. Species such as Phaseolus lunatus, Vigna unguiculata, Abelmoschus esculentus, and Glycine max are listed as hosts to T. neocaledonicus. However, very little is known about the bioecological aspects of this host-T. neocaledonicus interaction. The present study aims to determine the biological aspects (development and survival of immature individuals, reproduction, and fertility life table parameters) of T. neocaledonicus in P. lunatus, V. unguiculata, A. esculentus, and G. max. Individuals of T. neocaledonicus multiplied in laboratory were used on plants of P. lunatus to establish the experiments. To evaluate biological and reproductive parameters, three daily assessments were performed during the immature stages and one assessment during the adult stage. The mean developmental time from egg to adult was recorded. The highest mean was observed in V. unguiculata (13.57 days). Tetranychus neocaledonicus showed the highest fecundity in V. unguiculata, G. max and P. lunatus: 93.75, 93.38, and 79.10 eggs/female and longevity of 43.78, 33.42, and 47.26 days, respectively. Survival rate was above 50% until the 50th day in P. lunatus, 65th day in G. max and V. unguiculata, and 40th day in A. esculentus. The hosts G. max and V. unguiculata provided the highest net reproduction rates (R0) for T. neocaledonicus. The intrinsic rate of increase rm was lower when mites parasitized V. unguiculata and A. esculentus. This also happened for the finite rate of increase (λ). Host plants affect the performance and the biological, population, and reproductive parameters of T. neocaledonicus. Glycine max is the most favorable host for the development and reproduction of T. neocaledonicus.

Beta diversity of urban spontaneous plants and its drivers in 9 major cities of Yunnan province, China

Urbanization has significantly reshaped regional biodiversity structure globally. Previous studies suggested that urban communities of spontaneous plants are well adapted to the urban environment. However, a perspective of urbanization that accounts for the joint impacts of the current state (as expressed by urbanization intensity) and the historical progress of urbanization (as expressed by urbanization rate) to reveal the mechanisms underlying the biodiversity patterns of spontaneous plants in cities is still lacking. Here we present data and analysis of spontaneous plants sampled in 709 patches within 82 sites of built-up areas from nine cities distributed across climatic and floristic zones in Yunnan province, a biodiversity hotspot in China. We used the exponent (z) of a species accumulation curve (SAC) model to characterize beta diversity among patches in a site, and found a higher beta diversity of native species compared with non-natives, indicating that the species composition of native plants is more heterogeneous. The beta diversity of all species groups was best explained by the constant c of the SAC (a proxy of alpha diversity), followed by the urbanization intensity (as expressed by the proportion of sealed surface and patches’ Shannon diversity index), and urbanization rate (as expressed by the sealed surface expansion rate). Moreover, beta diversity of non-native species was additionally negatively correlated with altitude. Our results suggest that the interplay of natural environmental factors and human-induced urbanization shape diversity of urban spontaneous plants in Yunnan province. Our findings emphasize that urban spontaneous plants diversity is not only a reflection of the current state of urbanization, but also a consequence of historical processes of urbanization.

Insecticidal and repellent effects of Mentha longifolia L. essential oil against Aphis craccivora Koch (Hemiptera: Aphididae)

BackgroundChemical control is generally used against aphids. The harmful effects of the chemicals used in the control on the environment and human health have contributed to the development of alternative control methods. The main objective of this study was to determine chemical composition of Mentha longifolia L. essential oil obtained from spontaneous plants in Algeria, investigate repellent and con-tact toxicity effect on Aphis craccivora Koch control, and assess the impacts of essential oil on development, survival and reproduction of A. craccivora.ResultsThe essential oil showed a concentration dependent significant toxic and repellent effects. The highest effect was recorded for 8 μl/ml concentration of essential oil. The repellent effect and mortality rate in 8 μl/ml concentration were 84.37 and 80.66%, respectively. The values of LC50 and LC90 were 1.848 and 26.782 μl/ml, respectively. The effect of essential oil on immature period, adult longevity, natal period, survival, and fecundity was statistically significant (p < 0.05).ConclusionsThe findings in this study showed that the essential oil of M. longifolia harvested in the Tamanrasset region of Algeria has a toxic effect on A. craccivora, and can have a potential to be used as an insecticide to control A. craccivora. The use of environmentally friendly bioinsecticide will enable effective management of A. craccivora.Graphical

Organic farming increases functional diversity and ecosystem service provision of spontaneous vegetation in Mediterranean vineyards

Spontaneous plant species in agricultural systems (i.e., weeds) are bound to become key ecological indicators of agroecosystem resilience as they show high sensitivity to management, while they ensure the assembly of multiple ecological functions. Here we used the response-effect functional framework on spontaneous plant species growing in both organic and conventional vineyards, to assess whether their plant communities respond to contrasted farming systems and to soil conditions according to its competitive response and the provisioning of pollination services.The results show that the spontaneous plant communities and its functions better reflected the effects of management -when considering the dichotomy organic-conventional farming- rather than soil conditions. Organic management in vineyards promoted higher plant species richness, with varied competitive response strategies to deal with different environmental conditions and management disturbances. Organic vineyards held more diverse and resilient plant communities for the provisioning of pollinator services than the conventional ones, which is expected to enhance pollinator communities with diverse feeding guilds. In contrast, conventional farming systems selected anemophilous plants or those with flower attributes related to generalist pollinators.Such results highlight the significance of organic farming for the sustainment of the local accompanying plant diversity but also for the provisioning of ecosystem services in these agricultural landscapes. Besides, the study reinforces the applicability of the response-effect framework to identify the effects of vineyard management on the spontaneous plant communities and its potential impacts on the pollinator communities.

Microbiome Associated with Olive Cultivation: A Review

International research has devoted much effort to the study of the impacts caused to the soil by different management practices applied to olive cultivation. Such management involves techniques considered conventional, including the control of spontaneous plants with herbicides or machines, inorganic fertilizers, and pesticides to control pests and diseases. Equally, some producers use sustainable techniques, including drastic pruning, the use of cultivars that are tolerant to diseases and adverse climates, the use of organic conditioners in the soil, the maintenance of vegetation cover with spontaneous plants, and the use of inoculants, among others. In both conventional and sustainable/organic management, the effects on soil quality, crop development, and production are accessed through the presence, activity, and/or behavior of microorganisms, microbial groups, and their processes in the soil and/or directly in the crop itself, such as endophytes and epiphytes. Thus, our present review seeks to assemble research information, not only regarding the role of microorganisms on growth and development of the olive tree (Olea europaea L.). We looked mainly for reviews that reveal the impacts of different management practices applied in countries that produce olive oil and olives, which can serve as a basis and inspiration for Brazilian studies on the subject.

Spontaneous Plant Diversity in Urban Contexts: A Review of Its Impact and Importance

To promote sustainability in urban green spaces, it is necessary to know the diversity of spontaneous species in these spaces. Based on the investigation and analysis of the relevant scientific literature, the diversity of spontaneous species and their importance was contextually discussed, along with the assessment of local biodiversity impact in green spaces. Studies on green spaces, spontaneous flora, biodiversity or ecosystem services, and studies on exotic species and adaptability were summarized. Finally, the existing issues regarding biodiversity and urbanization, and the role of spontaneous plants in restoring industrial areas were discussed. Based on the research carried out, it is considered that green spaces contain unique and useful biodiversity resulting from their management. Spontaneous flora can be a generator of plants with aesthetic character, which can be grown in an ecologically sound way in private gardens and natural spaces in town and village zones, with certain remarkable farming-biological characteristics (ecological plasticity, high hardiness, etc.). Biodiversity is a relevant feature of urban landscapes, offering multiple gains, and the conservation of this biodiversity in urban green spaces is fundamental and requires an integrated approach. However, urbanisation usually has a detrimental influence on local species’ diversity.

Diversity and distribution variation of urban spontaneous vegetation with distinct frequencies along river corridors in a fast-growing city

River corridors are vital to urban ecology, regulating climate and providing habitats for animals. Spontaneous plants naturally colonize various spaces therein, where they play important roles. Previous studies have explored many factors driving spontaneous plant diversity at the city scale and in specific habitats. However, we lack a holistic understanding of the diversity and distribution of variation of spontaneous vegetation that directly reflects the effects of urbanization. We conducted a field study of 1250 sample plots along river corridors in Chengdu, a fast-growing city in China, and the spontaneous plants in fifteen microhabitat types were surveyed. Diversity and distribution patterns were examined for species with distinct dispersal abilities. There was a far greater richness of occasional species compared to dominant and common species, but occasional species were markedly less abundant. Vacant lots and natural riverbanks harbored the most species, but revetment walls and lawns also supported a considerable number of species, especially in the city center. Species diversity among different urban areas was strongly related to microhabitat conditions. The proportions of dominant, common, and occasional species varied among communities. In communities on vacant lots of less urbanized areas, the richness of dominant species was greater, whereas in green spaces created by planted vegetation, occasional species were more diverse. Green space microenvironments are hospitable to some rare species. Urbanization and microhabitats have co-effects and thus ultimately determine diversity and distribution patterns. Such patterns, if linked to ecological and ornamental value, can provide a new perspective and nature-based solutions to urban rewilding and landscape design.

Characterization of Cucurbit Aphid-Borne Yellows Virus (CABYV) from Passion Fruit in Brazil: Evidence of a Complex of Species within CABYV Isolates.

High-throughput sequencing (HTS) has been an important tool for the discovery of plant viruses and their surveillance. In 2015, several virus-like symptoms were observed in passion fruit (PF) plants in Bahia state, Brazil. Using HTS technology, bioinformatics tools, RT-PCR, and Sanger sequencing, we identified the cucurbit aphid-borne yellows virus (CABYV, Polerovirus, Solemoviridae) in co-infection with cowpea aphid-borne mosaic virus (CABMV, Potyvirus, Potyviridae) in PF, in green manure, and spontaneous plants in several localities in Bahia. Complete genomes of CABYV-PF isolates were determined and analyzed with other CABYV isolates available in GenBank that have been identified in various countries. Phylogenetic analysis and pairwise identity comparison with CABYV isolates showed that CABYV-PFs are more closely related to French and Spanish isolates. Overall, analyses of all the CABYV genomes revealed that these could represent ten distinct species, and we thus proposed reclassifying these CABYV as isolates into ten species, tentatively named "Polerovirus curcubitaeprimum" to "Polerovirus curcubitaenonum", and "Polerovirus melo". CABYV-PF is a member of "Polerovirus curcubitaeprimum".

Bringing spontaneous plants to cultivation: issues and constraints for medicinal and aromatic plants

Bringing spontaneous plants to cultivation: issues and constraints for medicinal and aromatic plants

Overview of the Success of In Vitro Culture for Ex Situ Conservation and Sustainable Utilization of Endemic and Subendemic Native Plants of Romania

Romania has a relatively high diversity of plant species, including 3829 vascular and 979 non-vascular spontaneous plant taxa (species and subspecies). Due to uncontrolled harvesting as well as other causes, including climate change and ecological collapse, the speed of species extinction and the narrowing of the genetic base of plant resources has been reported as a critical issue. Therefore, the national Red List of Romanian flora includes 1453 threatened taxa, of which 95 are endemic and 90 subendemic. Many of these have high ornamental, medicinal–cosmetic, and/or aromatic properties. The high extinction risk of these valuable plants has stimulated both the reconsideration of their vital importance as genetic resources and interest in finding effective methods for conservation. Cultivating these phytogenetic resources in a human-controlled environment is of high importance for effective ex situ conservation, which can further serve sustainable exploitation needs and may facilitate in situ conservation actions. In vitro culture is a powerful tool for producing elite plants for cultivation for different purposes. This review summarizes the current knowledge on in vitro multiplication of 22 endemic and subendemic native plants of Romania, examining the materials used, the treatments applied, and the results obtained in each stage of the micropropagation protocol (culture initiation, proliferation, rooting, and acclimatization). The findings from the reviewed studies are presented in a comparative way, and the potential of plant tissue culture in conservation and sustainable exploitation of these Romanian species is outlined.

Rentabilidade do cultivo orgânico de cenoura sob interferência de plantas espontâneas e métodos de semeadura

ABSTRACT Spontaneous plants in vegetable growing areas significantly impact yield and costs, regardless of the adopted cultivation system. This study aimed to evaluate weed interference periods on the profitability of organic carrot cultivation under different sowing methods. Two experiments were set up [weed control and coexistence, in a randomized block design arranged as split plots (5 × 2), with five cultivation periods: 15, 20, 25, 30 and 35 days after sowing] and two sowing methods were applied: direct and water-conditioned sowing. Based on the production data and technical coefficients, the economic evaluation of production was carried out, with calculation of production costs and revenues. The highest net revenue was obtained when the growing area was kept clean for 19 to 30 days. The total revenue increased linearly by R$ 0.33 m−2 for each day of weed control, while, for the coexistence treatment, it decreased by R$ -0.37 m−2. The water-conditioned sowing increased the economic indicators of the organic carrot cultivation.

Kulturowe czynniki postaw wobec „czwartej przyrody” w przestrzeni miejskiej

Cultural factors of attitudes towards "nature of the fourth kind” in urban space The return of spontaneous plants to the city is now considered a valuable process helping to balance degraded urban ecosystems (Kowarik, Körner 2005, Jakubowski 2019, 2020). However, research on public attitudes towards the “nature of the fourth kind” in the city and peri-urban areas shows that they are not unequivocally positive and are accompanied by conflicting feelings (Hunziker 1995, Bauer 2005, Sonti 2019). Addressing the issue of ambivalence associated with new wilderness, the article proposes its cultural interpretation. Firstly, it contextualises ambivalence as a contemporary form of the “numinous” experience (Otto 1999) that arises in encounters with the life dynamics of spontaneous plants that escape human control. Secondly, it identifies archetypal spatial figures of Western urban culture, namely wall and parcel, as cultural factors shaping attitudes toward the new wilderness both at the level of “situations” and “ideologies” (Kłoskowska 1973). Thirdly, it aims to reorient the view of new wilderness in the city with the use of the topological concept of “figuration” (Lash 2012) and the idea of thinking together with plants (Haraway 2016). The above issues are presented against the backdrop of two questions: about the politics guiding research on the social perception of the new wilderness and about the possibility of developing a more nuanced understanding of the “nature of the fourth kind” concept that goes beyond the scale of the wastelands by taking into account the micro-perspective of the mobile urban subject and the unconventional creativity of plants.

DIVERSITY OF SPONTANEOUS PLANTS IN PUBLIC GARDENS AT ARID ENVIRONMENTS

Public gardens are necessary to improve the quality of life, and wellbeing of urban residents. The objective of this study was to inventory the floristic diversity of spontaneous species in three sites representing different public gardens in southwestern Algeria. To document all spontaneous species present, a total of 64 quadrats were established in August 2021. To express differences in diversity between sites, the species richness and biological diversity index were used. A total of 375 individuals, representing 15 families, 29 genera, and 31 species were recorded. The family Asteraceae is represented by the highest number of species (7 species) followed by Amaranthaceae and Poaceae (5 species), whereas, 10 families are represented by one species each. Therophytes (58.06%) and Chamephytes (16.13%) are relatively high life forms of the vegetation spectra. Phytogeographical analysis of the vegetation in the area revealed the forte representation of cosmopolitan elements. The ranges of diversity indices observed in the three sites were: Shannon- Weaver index (2.99-3.86), Evenness index (0.76-0.88) and Sørensen coefficient (53%-61%). The application of principal component analysis to the data characterized the ecological gradients responsible for the distribution of these taxa at the level of the three sites. This study contains important information on spontaneous plants in arid environments, which should be integrated into the priority of plant genetic resources valorization programs.