Spontaneous Vegetation Research Articles

Enhancing the Rural Landscape Character: The Low Frequency of Inter-Row Wildflower Meadow Harvest Positively Affects Biodiversity While Maintaining Grape Quantitative and Qualitative Traits in a ‘Sultanina’ Vineyard in Greece

The development of inter-row wildflower meadows in vineyards could restore and preserve biodiversity as well as enhance the local rural landscape character. Herein, the prospect of inter-row development of a wildflower meadow from spontaneous vegetation growing within a table grape ‘Sultanina’ vineyard was studied for two years through the effect of different intensities of harvest on the meadow composition, arthropod presence, and grape vine produce. Three harvest treatments (constant, periodic, and none) were examined. The growth (height and area of groundcover) and number of plants per species that composed the inter-row wildflower meadow as well as the insects found within it and on the grape vine plants were recorded. At maturity, the main quantitative (yield/vine) and qualitative characteristics (soluble solids, pH, and total titratable acidity) of the grapes were evaluated. Results showed that both the quantitative and qualitative characteristics of the grape vines did not differ between treatments. The inter-row vineyard meadow composition that constituted of 21 herbaceous species did not differ between the periodic- and no-harvest treatments. Insect pests hosted within the meadow did not pose a threat to ‘Sultanina’ grapes, although thrips within the inter-row meadow showed a preference for Convolvulus arvensis. The overall results suggest the application of either a periodic- or no-harvest on the spontaneous vegetation of a Mediterranean ‘Sultanina’ vineyard over two years and constitutes the development of inter-row wildflower meadows from spontaneous vegetations as an appealing and promising sustainable vineyard floor management practice for permanent use that needs to be further researched.

Determinants of Evapotranspiration in Urban Rain Gardens: A Case Study with Lysimeters under Temperate Climate

Accurate evaluation of evapotranspiration (ET) flux is an important issue in sustainable urban drainage systems that target not only flow rate limitations, but also aim at the restoration of natural water balances. This is especially true in context where infiltration possibilities are limited. However, its assessment suffers from insufficient understanding. In this study, ET in 1 m3 pilot rain gardens were studied from eight lysimeters monitored for three years in Paris (France). Daily ET was calculated for each lysimeter based on a mass balance approach and the related uncertainties were assessed at ±0.42 to 0.58 mm. Results showed that for these lysimeters, ET is the major term in water budget (61 to 90% of the precipitations) with maximum values reaching 8–12 mm. Furthermore, the major determinants of ET are the existence or not of an internal water storage and the atmospheric factors. The vegetation type is a secondary determinant, with little difference between herbaceous and shrub configurations, maximum ET for spontaneous vegetation, and minimal values when vegetation was regularly removed. Shading of lysimeters by surroundings buildings is also important, leading to lower values. Finally, ET of lysimeters is higher than tested reference values (evaporimeter, FAO-56, and local Météo-France equations).

Evaluation of potentially available nitrogen by biological and chemical methods in soil cultivated with maize in succession to cover crops

Estimating mineralization rates is one of the best ways to predict N availability over time. However, different methods can lead to distinct predictions, especially when different production systems are used. The aim of this study was to compare biological and chemical methods commonly used to estimate the potentially available N in a soil cultivated with maize in succession to cover crops and N fertilization. The experimental area has been cultivated with cover crops (jack bean, velvet bean, millet and spontaneous vegetation) and N fertilization (0, 60, 120 and 180 kg N ha−1) since the year 2000 in a split-plot design with cover crops as the main treatments and N rates as secondary treatments. The biological evaluation of N mineralization was performed by means of an aerobic incubation of soil samples, while the chemical methods were either by the use of saline ((Ca(H2PO4)2, CaCl2, KCl) and Illinois soil test and direct steam distillation (DSD). Soil C and N contents were not affected by the cover crops, even after sixteen years of cultivation. The utilization of N by maize plants was affected by cover crops, especially for jack bean, while N fertilization led to a maximum absorption point, estimated in 158 kg N ha−1. The methods for evaluating the potentially available N behaved differently among treatments. The DSD method has significantly correlated with maize N uptake and yield, which demonstrates that it was the most promising method to estimate the potentially available N, although it is not yet calibrated for all agricultural systems.

Farming Intensity Affects Soil Seedbank Composition and Spontaneous Vegetation of Arable Weeds

Former studies carried out in the 2000s in the Lahn-Dill region located in the middle-east of the German state Hesse stated a depletion of arable weeds on the field scale and more diverse weed flora on the landscape scale. Current study, having started in 2018, aims to contribute to a better understanding of the interactions between arable weed species diversity, farming intensity, grown crops and landscape area. Moreover, the potential of organic farming methods for conservation and promotion the arable weed diversity is aimed to be assessed with the study. In total, 42 fields in two landscape regions were sampled—six seedbank samples were collected from each field; additionally, data on spontaneous arable weed flora were recorded each spring from 2019 to 2021; emerged aboveground weeds were identified in the fields and their coverage was documented. Four factors were considered in the field trial: Farming practice, landscape area, soil depth and the current crop. Effects of these factors on arable weed species diversity were calculated with a Generalized Linear Model (GLM), resulting in significant effects of the management system, the area and the current crop. Among the four organic farming systems that were sampled, the time period of organic growing had a significant effect on weed seed numbers in the soil with an increase in seed numbers. Average seedbank species numbers were around twice as high in organic farming systems (18 species) compared to conventional managed fields (nine species). Evidence of an ongoing species decline in the region on the landscape scale could be detected by comparison with a former study. Especially rare and endangered weed species are a concern due to seedbank and current vegetation depletion tendencies.

Low productivity substrate leads to functional diversification of green roof plant assemblage

Green roofs are roof free spaces where living organisms can find an appropriate habitat to colonise. The establishment of plant species with different functionality can enhance biodiversity and provide ecosystem services. However, drought and nutrient availability can affect the plant development. The extensive green roof was set up in Pisa (Italy) in 2014, 12 modules of 10 cm depth were filled with three substrates composed of compost from municipal mixed waste, pelletised paper sludge, and commercial tephra product (Vulcaflor), as follows: Vulcaflor + compost, Vulcaflor + pellet + compost, and Vulcaflor + pellet, characterised by decreasing level of nitrogen content. The species planted in 2014 were chosen from the herbaceous spontaneous vegetation of urban and rural swards not often mowed, plus two sedum species. After the establishment phase, the green roof community was progressively dominated by Sedum species and other species were seeded in 2016. In 2018–19 the plant functional types and the community structure were monitored. Besides seasonal fluctuations, nitrogen shaped the composition of the community, and Sedum species showed high cover values in nitrogen-richer substrates. Annual forbs colonised the plots with a lower nitrogen content. In summer, the number of species drastically fell, and Sedum album was dominant in the three substrates. Seedling recruitment regenerated the community in the cooler season, increasing the diversity in the poor substrate. The scarcity of nitrogen led to the development of stress-tolerator annuals increasing the biodiversity in the rainy-cool season. Annual species constitute a transient seed bank which enables the system to regenerate when rain follows periods of heat and drought.

Landscape transformations in Albania. A photographic survey on the traces of Italian travellers in the Balkans


 
 
 After the fall of the Ottoman Empire, Albania became a possible land of conquest for Italy, France, and Austria. Explorations and surveys of the newly liberated territory involved numerous scientific a nd military expeditions. At the end of the nineteenth century, the Reale Società Geografica Italiana had been carrying out a systematic study of Albanian landscape, mainly aimed at geographical research. Relevant Italian scholars and geographers travelled to Tirana and Valona. Antonio Baldacci (1867-1950) between 1892 and 1902, Roberto Almagià (1884-1962), Aldo Sestini (1904-1988) in 1940, Bruno Castiglioni (1898-1945) who recorded geomorphological aspects as an army officer following Italian troops. Two expeditions in 1940 allowed them to collect all the information needed to publish the fundamental monograph “L’Albania”, printed in 1943. Bruno Castiglioni oversaw the geomorphological aspects of the study, Ferdinando Milone covered anthropology and economics, and Aldo Sestini investigated the geographical features of each region. Another landmark contribution is Antonio Baldacci’s Itinerari albanesi: (1892-1902), which described discovering an obscure land, its natural features and the built environment.
 The contribution for the sixth issue of Sophie draws on a photographic campaign carried out between July 2016 and June 2018, and currently being finalised in the form of a Catalogue of Landscape Typologies. The author c onducts a photographic c ampaign a long the s ame itineraries covered by the aforementioned geographers, discovering similarities and differences with the contemporary Albanian landscape. Manuscripts, diplomatic accounts, publications, and photographs produced by Italian travellers of the early twentieth century are being compared with the current status of the visual environment. Tourism-related activities have altered the scenery of the coast, particularly the so-called Riviera that connects Vlorë with Sarandë, while other sectors of the northern mainland have remained relatively unchanged.
 This ongoing research is expected to inform a general catalogue of Albanian landscapes, intended as a tool for planning future interventions across the country. The catalogue could be a useful tool to build an alternative visual cartography. The Catalogue of Landscape Typologies collects four hundred geolocated shots of selected views, which have been classified and redrawn to identify recurring features and visual landmarks. Images are being disassembled in coherent morphological layers: woods, agricultural plains, cultivated slopes, spontaneous vegetation fields, urbanization areas, water bodies and the profile of the mountains. Contemporary Albania and other countries in the Balkans are rapidly changing the quality of its built environment in an attempt to emerge and progress towards the European standards. On the other hand, one could argue that unique views can be lost along the way.
 
 

Assessment of the Transfer of Trace Metals to Spontaneous Plants on Abandoned Pyrrhotite Mine: Potential Application for Phytostabilization of Phosphate Wastes.

The abandoned Kettara pyrrhotite mine (Marrakech region, Morocco) is a real source of acid mine drainage (AMD) and heavy metal pollution from previous mining operations—which has spread, particularly because of wind erosion. A store-and-release cover system made of phosphate wastes was built on the site for preventing AMD. To ensure the integrity of this cover and its durability, it is desirable to revegetate it (phytostabilization) with plants adapted to the edaphoclimatic conditions of the region. In this paper, a study was carried out on the spontaneous vegetation around the phosphate cover in order to consider the selection of plants to promote the stabilization of the Kettara mine tailings pond. Nine species of native plants with their rhizospheric soils growing in agricultural soils and tailings from the Kettara mine were collected, and metals (As, Cd, Co, Cu, Pb, Zn, Ni, Cr) were analyzed. The soil analysis showed that the tailings contained high concentrations of Cu (177.64 mg/kg) and Pb (116.80 mg/kg) and that the agricultural soil contained high concentrations of As (25.07 mg/kg) and Cu (251.96 mg/kg) exceeding the toxicity level (Cu > 100 mg/kg, Pb > 100 mg/kg, As > 20 mg/kg). The plant analysis showed low trace metal accumulation in Scolymus hispanicus, Festuca ovina, Cleome brachycarpa, Carlina involucrata and Peganum harmala. These species had a bioconcentration factor (BCF) greater than 1 and a translocation factor (TF) less than 1, demonstrating a high tolerance to trace metals. Therefore, they are good candidates for use in the phytoremediation of the Kettara mine tailings. These species could also potentially be used for the phytostabilization of the phosphate waste cover of the Kettara mine, thus completing the rehabilitation process of this area.

Chemical and microbiological changes in the soil mediated by different vegetative coverings in a Natal orange orchard

Proper soil cover management for citrus cultivation can contribute to increased productivity and improved soil quality. This study examined five different vegetative coverings [Urochloa brizantha; U. decumbens, U. ruziziensis, spontaneous vegetation, and herbicide application (glyphosate) in the total area] in the inter rows of a Natal orange orchard [Citrus sinensis (L.) Osbeck] grafted on the Swingle citrumelo (C. paradisi × Poncirus trifoliata). Their effects on the microbiological and chemical attributes of the soil and the vegetative development in the orchard were examined. Chemical (Ca2+, Mg2+, K+, P, pH, H+Al, CECpH7, base saturation, and OM) and microbiological (carbon and nitrogen of microbial biomass, basal respiration, and metabolic quotient) soil attributes in the rows and inter-rows were evaluated for the orchard in 2018 and 2019. There was a significant difference for most variables in the 2 years studied, emphasizing 2019 for microbiological parameters and OM, with the latter being 14.8% lower in the treatment with glyphosate in the total area compared to the treatment with spontaneous vegetation. The results showed the benefits of vegetation cover with brachiaria in inter-rows of the Natal sweet orange orchard in the chemical and microbiological attributes of the soil, especially in carbon and nitrogen of the microbial biomass.

Spontaneous Vegetation as an Alternative to Cover Crops in Olive Orchards Reduces Water Erosion and Improves Soil Physical Properties Under Tropical Conditions

Spontaneous Vegetation as an Alternative to Cover Crops in Olive Orchards Reduces Water Erosion and Improves Soil Physical Properties Under Tropical Conditions

Socio-Ecological Dimensions of Spontaneous Plants on Green Roofs

Green roofs have the potential to provide socio-ecological services in urban settings that lack vegetation and open space. However, implementation of green roofs is limited by high construction and maintenance costs. Consequently, green roof projects often disproportionately benefit wealthy communities and can further marginalise disadvantaged communities by increasing property values and housing costs. Vegetation cover on green roofs is crucial to their provisioning of socio-ecological services. Evidence suggests that green roof plantings change over time, especially with limited maintenance, and are replaced with spontaneous “weedy” species. This is often perceived as a failure of the original green roof design intent and spontaneous species are usually removed. However, where good coverage is achieved, spontaneous vegetation could provide beneficial services such as stormwater mitigation, habitat provision, and climate regulation. While social norms about “weediness” may limit the desirability of some spontaneous species, research suggests that their acceptability on green roofs increases with coverage. As spontaneous species can establish on green roofs without irrigation and fertiliser, reduced input costs could help facilitate adoption particularly in markets without an established green roof industry. Construction costs may also be reduced in hot and dry climates where deeper substrates are necessary to ensure plant survival, as many spontaneous species are able to colonise shallow substrates and can regenerate from seed. If implemented based on socio-ecological need, green roofs with spontaneous vegetation coverage may apply less pressure to property values and housing costs than conventionally planted green roofs, increasing the resilience of urban communities while limiting gentrification.

Unused railway lines as a contributor to bird abundance, species richness and diversity in intensively managed farmland

Agricultural landscapes are characterized by a variety of habitats resulting from man-made transformations of the natural environment. Progressing agricultural intensification is leading to a reduction in natural and semi-natural habitats, resulting in turn in a loss of biodiversity. In farmland, natural habitats such as field margins, hedgerows, and meadows are progressively declining or being transformed. There is a need for regionally adjusted schemes that balance agricultural production and biodiversity conservation due to strong differences even within one country. We present a potential tool that can mitigate biodiversity loss in farmland ecosystems. In this study, we compared transects on three different habitat types: unused railway lines, dirt road verges and fields in terms of overall, farmland and open land bird species abundance, richness and Shannon-Wiener diversity index as well as community composition in intensively managed agricultural landscapes. We predicted that 1) bird abundance, species richness and diversity would be greater in vegetation structure along unused railway lines due to their spontaneous vegetation character than in other habitats, and 2) bird community composition would be different between three habitat types (unused railway lines, farmland roads and transects in farming areas). Our findings demonstrated that habitats along unused railway lines provide a suitable environment for farmland birds, increasing bird diversity in the agricultural landscape and playing a wider role in biodiversity conservation. Vegetation structures along unused railway lines may act as alternative refuges for birds in each season, providing food resources, nesting, shelter, perching, singing, and resting sites as well as constitute a kind of ecological corridor running within an intensively used agricultural landscape.

Weeds in action: Vegetal political ecology of unwanted plants

This paper presents a vegetal political ecology of weeds. Weeds have barely been analysed in the burgeoning field of ‘more-than-human’ scholarship, this despite their ubiquity and considerable impact on human social life. We review how geographical scholarship has represented weeds’ material and political status: mostly as invasive plants, annoying species in private gardens and spontaneous vegetation in urbanized landscapes. Then, bringing together weed science, agronomic science and the critical geography of agriculture, we show how weeds ecology, weeds management and the environmental problems which weeds are entangled have critically shaped the industrial agriculture paradigm. Three main arguments emerging from our analysis open up new research avenues: weeds’ disruptive character might shape our understanding of human-plant relationships; human-weeds relation in agriculture have non-trivial socio-economic and political implications; and more-than-human approaches, such as vegetal political ecology, might challenge dominant modes of considering and practicing agriculture.

Herbivore exclusion and active planting stimulate reed marsh development on a newly constructed archipelago

Wetlands provide vital services on which human societies depend. As they have been rapidly degrading due to anthropogenic impacts worldwide, wetland restoration is increasingly applied. When a return to the original state of a wetland is constrained, forward-looking restoration can provide a new way to enhance an ecosystem's ecological integrity. However, the direction in which new ecosystems will develop is strongly coupled to the initial environmental conditions and may benefit from active decisions on (future) management.To improve the natural values of a degrading freshwater lake in the Netherlands, a forward-looking restoration project was initiated in lake Markermeer in 2016, involving the construction of a 700-ha archipelago called the “Marker Wadden”. This archipelago should provide new habitat to higher trophic levels in the lake's food web through the development of currently missing Common reed (Phragmites australis) dominated marshlands with gradual land-water transitions. However, the restoration project faces strong grazing pressure by Greylag geese (Anser anser) that possibly inhibit reed establishment.Here, we aimed to unravel the effect of herbivory by Greylag geese (using exclosures) and the introduction of reed rhizomes on early vegetation development and carbon dynamics on the bare soils of this new ecosystem in a manipulative field experiment. Our results showed that excluding herbivores strongly increased reed-vegetation cover, density and maximum height, but only when reed rhizomes were actively introduced. Spontaneous vegetation development on bare soils was limited, and colonization by Broadleaf cattail (Typha latifolia) dominated over reed. Net ecosystem exchange of carbon and ecosystem respiration were strongly linked to vegetation development, with highest methane emissions in the most densely vegetated plots.We conclude that the establishment of reed marshes can strongly benefit from excluding herbivores and the introduction of reed, and that otherwise other vegetation types may establish more slowly in newly created wetlands. This illustrates how active management of vegetation development has the potential to benefit novel ecosystems.

Artificial field defects: A low-cost measure to support arthropod diversity in arable fields

Biodiversity is rapidly declining worldwide, with agricultural intensification being among the main drivers of this process. Effective conservation measures in agricultural landscapes are therefore urgently needed. Here we introduce a novel low-cost conservation measure called artificial field defects, i.e., areas where crop is not sown and spontaneous vegetation grows. To evaluate their biodiversity potential, we compared abundance and species richness of various arthropod taxa between artificially created field defects and control plots within oilseed rape (OSR) fields. The effectiveness of field defects to support biodiversity was examined using an experiment with a factorial design comparing OSR flowering and ripening phases, location of field defects (field edge vs interior) and field defect type (sown with a nectar-rich plant vs no sowing). Arthropod sampling was conducted by employing several complementary methods: pitfall trapping, pan trapping, sweep netting and individual counting. Butterflies, true bugs, bees and wasps were more abundant and species-rich in both types of defects than in OSR controls. In contrast, ground-dwelling taxa had more individuals and species in controls. Overall, arthropod abundance and species richness increased, and field defects became relatively more attractive, during OSR ripening compared to OSR flowering. Location of defects had little effect, with only butterfly and spider assemblages being more abundant and species-rich at field edges compared to interiors. Our data indicate that artificial field defects can provide a simple agri-environmental measure to support various arthropod groups. However, further studies are needed to assess their biodiversity value at the landscape scale, and evaluate the balance between costs and benefits for farmers.

Polyphenols leaching and seed dormancy in carob (Ceratonia siliqua L.) in relation to hot water treatment

Carob (Ceratonia siliqua L.) is a relevant element of the Mediterranean spontaneous vegetation. Moreover, it is useful in reforestation, and it is currently re-valued for sustainable agriculture in dryland areas. However, the difficulties tied to carob propagation (mainly seed dormancy) hamper its large-scale cultivation. In this paper, the effects of four seed treatments (no treatment [control], soaking at 70 °C and 90 °C in water, or in 96% sulphuric acid) on five carob genotypes germination were studied. As compared to the very low germination of untreated seeds (0–13% germination), sulphuric acid (93–100% germination) and 90 °C water soaking (from 72 to > 90% germination in four out the five genotypes) were effective in promoting germination. Soaking at 90 °C resulted in the leaching of a higher amount of total polyphenols from the genotypes seed coat as compared to soaking at 70 °C. A significant correlation (0.75**) was ascertained between polyphenol leaching of the different genotypes and germination. These results suggest that dormancy in this species is not primarily associated with seed coat hardness, as it is generally thought, but also with the release of polyphenols. Polyphenols determination of the dormant and the few non-dormant seeds of the different genotypes also seem to confirm this hypothesis since these last showed an almost halved total polyphenols content (on average 17.0) as compared to dormant ones (34.8 mg g−1 of seed FW). Further studies may determine the polyphenols involved, but also assess new, easier to carry out, seed treatments. The important role of the galactomannans on seed germination of carob is also discussed. Finally, similar studies may enhance the knowledge of dormancy processes in other Fabaceae species whose germination is positively affected by hot water treatments.

Spontaneous vegetation succession and recovery of ecosystem structure and function in a 40-year abandoned stone quarry in a Mexican tropical dryland

Background: The restoration of sites degraded by stone quarrying in drylands requires expensive interventions. However, these interventions cannot be used in tropical drylands because rural communities lack financial resources. Spontaneous vegetation succession may help restore degraded sites. However, spontaneous succession is evaluated by only comparing species composition between degraded and reference sites, without considering the structure and function of degraded sites. Question: Can spontaneous succession restore the structure and function of sites degraded by stone quarrying? Study sites and dates: San Rafael Coxcatlán, Puebla, 2013. Methods: We evaluated nine indicators of ecosystem structure and function in 4 degraded sites abandoned for 40 years and 1 reference site. Results: Spontaneous succession partially restored the structure and function of degraded sites. In all degraded sites, herb cover (20-49 %) and biocrust cover (21-51 %) were similar to those in reference site (19 %, 56 %). Three degraded sites also had canopy covers (57-76 %), shrub covers (51-52 %), and bare ground covers (2-3 %) similar to those in reference site (80 %, 42 %, 2 %). However, one degraded site displayed the opposite pattern (32 %, 8 %, 14 %). All degraded sites had lower tree cover (0-2 %), visual obstruction (6-25 %), and litter cover (3-30 %) than the reference site (21 %, 66 %, 77 %). Conclusions: Spontaneous succession helped restore the structure and function in some degraded sites.

The Study of Transformed Herbaceous Vegetation in the Area Flooded Due to Coal Mine Workings

Abstract The spontaneous vegetation in permanent flooding zone around technogenic water bodies arising on former pastures due to underground coal mining in the Western Donbass basin (steppe zone of Ukraine) was studied in 2018–2019. Occurrence and abundance of herbaceous plants were taken into account in 36 vegetation plots over a total area of 0.8 km2 in different habitats: dry, wet and flooded. In total, 83 plant species belonging to 31 families and 66 genera were identified, among which perennials dominated. Strong negative Pearson’s correlation was found between the amount and abundance of plant species and soil characteristics across the studied habitats, where the joint action of all edaphic factors determined the mosaic appearance of transformed vegetation. The spontaneous vegetation of the least disturbed xero-mesophilic habitats was most similar to (semi)natural grasslands, while the vegetation of hygrophilic habitats had a complete mismatch. Surrounding grasslands were not the most important diasporas’ source for spontaneous succession in the disturbed zone, and many species were supposed to come from the more remote areas. Recovery of target vegetation did not occur for 25 years of permanent subsidence and flooding due to radical transformation of landscape and soil and appearance of completely inappropriate habitats. At the same time, the unusual species composition of spontaneous vegetation and significant number of rare and endangered plants indicate the formation of valuable biotopes in the subsidence and flooding zone.

Are acts of selective planting and maintenance drivers for vegetation change in stormwater systems? A case study of two infiltration basins

Infiltration basins have been designed to receive and infiltrate stormwater. Upstream, the stormwater runs off urban surfaces, is collected by the sewer system, and then routed to infiltration basins. Then, the suspended solids carried by stormwater accumulate at the surface and form a sedimentary layer. Plants then colonize the soil surface and shape a new ecological system, ruling at the same time water quality and quantity. In this study, we monitored the dynamics of vegetation over two decades in two infiltration basins. One of these basins was subjected to vegetation maintenance (planting and mowing once every year), whereas the other basin was left to be colonized by spontaneous vegetation. Basic maintenance (1/year) may change the species at the beginning of the operation of the basins, but the impact is short term. However, this may be sufficient to prevent the growth of some invasive species. In the long term, spontaneous vegetation and water regimes turn the original ecosystem into a new one, combining initial planted species with new species. Our results show that the water regime seems to be the main factor controlling vegetation and that dry conditions allow the establishment of grasslands with typical plant species. Vegetation maintenance and the management of water levels may help prevent the establishment of invasive species and maintain species for the optimal functioning of infiltration basins.

Ecology typological assessment of forest vegetation of the North-Eastern Forest-Steppe of Ukraine

Recently, significantly increases the need for a detailed study of various aspects of the modern natural, spontaneous and artificially generated phytodiversity as the main element of the formation and regeneration of natural ecotypes structural elements for building national ecological network. It is necessary to examine various aspects of the natural and spontaneous vegetation formed. Based on the ecological specifics of the North-Eastern Forest-Steppe of Ukraine, a detailed analysis of natural and artificially formed forests on the floodplain, pine terrace and plateau of the rivers of the Dnieper and Seversky Donets basins, as well as in ravine-beam systems is required. Peculiarities of forest vegetation conditions, distribution of tree species and ecological conditions of their growth are given. According to forest management data, the area of the North-Eastern Forest-Steppe covered with forest vegetation is 336110.3 ha. The distribution of forest areas by edatopes is as follows: trophotopes — oak wood (220640.2 ha, 65.64%), sugruds (54739.2 ha, 16.29%), subors (52174.5 ha, 15.52%) and pine forests (8556.4 ha, 2.55%); hygrotopes — fresh conditions (282960.3 ha, 84.19%), dry (35576.7 ha, 10.59%), damp (12179.5 ha, 3.62%), moist (4634.3 ha, 1.38%), wet (749.0 ha, 0.22%) and very dry conditions (10.5 ha, 0.003%). There are 38 types of forests areas covered with forest vegetation, which are dominated by fresh maple-linden forest (183442.0 ha, 54.58%), a slightly smaller area occupied by fresh oak-pine forest (47040.9 ha, 14.00%) and linden-oak-pine sugrud (33999.3 ha, 10.12%), as well as dry maple-linden forest (28697.7 ha, 8.54%). The composition of forest-forming species is quite diverse and is represented by 60 species of woody and shrubby plants. The main forest-forming species is Quercus robur (190153.9 ha, 56.58%). Pinus sylvestris (86212.1 ha, 25.65%) and Fraxinus excelsior (20318.5 ha, 6.05%) have slightly smaller areas, all other species occupy small areas. Research a variety of forest habitats will provide an opportunity to plan the conservation, reproduction and protection of phytodiversity, including species of sozophytes from different conservation lists, as well as to balance the provision of ecosystem services by tree and shrub plantations of the North-Eastern Forest-Steppe of Ukraine.

Spontaneous vegetation in the horticultural belt of La Plata as host of Thripidae (Thysanoptera) vectors of Tospovirus: Relative risk as an epidemiological component

Black Death is a virosis caused by the Tomato Spotted Wilt Virus (TSWV), transmitted by thrips, and represents a complex problem since weed hosts for thrips vectors and the virus is accentuated as virus reservoir and vector sustenance. The objective was to generate, from a list of weeds that act as hosts for the four vector thrips species in the horticultural belt of La Plata, a relative risk categorization as an epidemiological component. Between 2000 and 2003, three sites were selected within the horticultural belt of La Plata (Buenos Aires, Argentina) where flowers of 21 weed hosts of Frankliniella occidentalis, Frankliniella schultzei, Frankliniella gemina and Thrips tabaci were sampled monthly (60 in total). For analysis, the sampling results were grouped into three annual seasons, corresponding to the phenology of greenhouse crops in the region. For the four thrips vectors, the abundance of adult thrips and the presence of their larvae were considered using an unsupervised hierarchical cluster analysis and the DGC multivariate mean comparison test to obtain the number of significant groups. From this base grouping, three risk groups (RG) were defined as a source of inoculum for these vectors: high (H), medium (M) and low (L) according to the status of the reproductive host (RH). The groups that emerged were: (H): RH of F occidentalis, (M): RH of F. schultzei and T. tabaci, and (L): RH of F. gemina or non-vector thrips. Periodic survey and early flowering suppression of nine weed species categorized as high risk is proposed. This implies the continuous monitoring of three weed species, to which other companion weeds are added according to the growing season.