Weed communities of root crops in the Pamir Alai Mts , Tajikistan ( Middle Asia )

According to the ten-volume flora of the former Soviet Socialist Republic of Tajikistan [1–8], supplemented by the works of Zakirov [9], Tzvelev [10], and Ikonnikov [11], ca. 4550 vascular plant species occur in Tajikistan. This number is not final, as recently some new records regarding the Tajik flora have been published (e.g. [12–17]). Moreover, some species new to science have been described based on plant specimens collected in the general area of this country (e.g. [18–25]). Tajik vascular plant flora is considered as among the richest in the area of the former Soviet Union. This area is also recognized as one of the most important centers of weed species in the world [26]. Approximately 30% of vascular plant species known from Tajikistan are generally accepted endemics of the country [8,27,28]. It is worth mentioning that the Pamir-Alai range is part of the middle Asian mountain system recognized by Conservation International to be among thirty-four so-called hotspots of biodiversity [29] and as one of the eleven most important focal points of future plant diversity studies and conservation [30]. On the other hand, having the near-lowest adaptive capacity to climate instability, Tajikistan is regarded as the country most sensitive in the world to climate change [31]. According to Baettig et al. [32], it is exposed to a high risk of climate change, which is going to be one of the most important degradation factors for the vegetation cover of the country. Recent syntaxonomical studies of segetal communities have been carried out for several years now in many regions of the world, mainly in countries of Central Europe (e.g. [33–39]) and Asia [40–42]. For several regions similar in terms of climatic conditions (the Mediterranean and Irano-Turanian geobotanical provinces) useful data regarding field communities are available, e.g. for Afghanistan, Serbia, Italy, Greece, Romania, Bulgaria, and Spain [43–50]. There is little data from the Saharo-Sindian province, where numerous weed species ranging as far as Tajikistan in the east originate [51–53]. Unfortunately, to date, in some regions of Central Asia, for example in Kyrgyzstan, Kazakhstan, or Uzbekistan, no research on the plant communities of these field ecosystems has been conducted. This applies to cereal as well as root crops. Research on agrocoenoses has been carried out across the globe, within a range of contexts and with different levels of intensiveness. Recently, a large number of papers have documented the problem of maintaining conservation values for agrocoenoses in relation to the intensification of crop production. In Europe as well as in Asia, for cereal and root crops, a decrease in biodiversity has been noted, as exemplified by the Abstract


Introduction
According to the ten-volume flora of the former Soviet Socialist Republic of Tajikistan [1][2][3][4][5][6][7][8], supplemented by the works of Zakirov [9], Tzvelev [10], and Ikonnikov [11], ca.4550 vascular plant species occur in Tajikistan.This number is not final, as recently some new records regarding the Tajik flora have been published (e.g.[12][13][14][15][16][17]).Moreover, some species new to science have been described based on plant specimens collected in the general area of this country (e.g.[18][19][20][21][22][23][24][25]).Tajik vascular plant flora is considered as among the richest in the area of the former Soviet Union.This area is also recognized as one of the most important centers of weed species in the world [26].Approximately 30% of vascular plant species known from Tajikistan are generally accepted endemics of the country [8,27,28].It is worth mentioning that the Pamir-Alai range is part of the middle Asian mountain system recognized by Conservation International to be among thirty-four so-called hotspots of biodiversity [29] and as one of the eleven most important focal points of future plant diversity studies and conservation [30].On the other hand, having the near-lowest adaptive capacity to climate instability, Tajikistan is regarded as the country most sensitive in the world to climate change [31].According to Baettig et al. [32], it is exposed to a high risk of climate change, which is going to be one of the most important degradation factors for the vegetation cover of the country.abandonment of unprofitable crops (especially in middle and higher mountain elevations) and intensification of the production of others [54][55][56][57][58][59][60].
In some regions of the world, relationships between the richness of vegetation patches and various abiotic factors, as well as the abundance of weed flora in crop communities, e.g.altitude, soil type, climate, etc., have been relatively well studied [61][62][63][64][65].
A number of studies have appeared recently, which record basic floristic and vegetation data for root crops or cereals, often focusing on their special role for the protection of threatened or endemic species [66][67][68][69][70].As well, vanishing and rare species, and communities related to agricultural land and weed habitats other than agrocoenoses, have been a center of attention for botanists in recent years [58,[71][72][73][74][75][76].Additionally, changes in segetal flora over the years have been analyzed (e.g.[77]).The growing interest in endangered weed species is the reason for the first conservation projects involving extinct or disappearing taxa (e.g.[78]).Specific biological features, which are probably responsible for weed regression (e.g.[79]) or expansion (e.g.[80]) have received less attention.Therefore, it is nearly incomprehensible that within one of the world's cradles of weeds, virtually no conservation research focused on weed flora has been conducted.
Phytosociological research is essential in order to document the syntaxonomic diversity of weed phytocoenoses.Unfortunately, only a few works focused on vegetation classification have been issued recently [81][82][83].They are all the more important because so far there have been no syntaxonomic works on segetal communities published on this country, even though the vegetation is so rich and relatively well preserved due to the low intensity of cultivation.Outside Middle Asia, segetal weed vegetation studies have been conducted for a few areas situated a bit further within the region, e.g.Bashkortostan (southern Urals) and Mongolia in Central Asia [41,42,84].

Study area
Tajikistan covers 143500 km 2 and is situated in the Middle Asia between E 36°40'-41°05' and N 67°31'-75°14' (Fig. 1).This is a typically mountainous country, with more than 50% of the area located above 3000 m.The southern part of Tajikistan is influenced by a subtropical climate, while the northern part is situated in the temperate climate zone [85].Generally, the country is characterized by high insolation, a low percentage of cloud cover, high amplitude of annual temperatures, low humidity and low precipitation.In subtropical regions of Tajikistan, the average temperatures in June are around 30°C.In the temperate zone, which in Tajikistan comprises mainly the high mountains, the climate is much harsher, with average temperatures in July between 9.7°C and 13.5°C.Annual precipitation in Tajikistan ranges from ca. 70 mm (in the Pamirs) to ca. 600 mm (in the Hissar Range).The lower limit of perpetual snow is at an altitude of 3500-3600 meters above sea level in the western part of the country, 5800 m in the eastern regions (Fig. 2) [86,87].The cultivation zones are distributed in accordance with the perpetual snow cover, from ca. 350-3300 m in western Tajikistan up to about 4800 m in eastern Pamir.
This study was conducted in the northern, northwestern, southwestern and southeastern parts of Tajikistan, mainly in the valleys of the Syr Darya, Amu Darya, Pyandzh, Veshan, Vakhsh, Zeravshan, Kafirnighan, Khanaka and Surkhan Darya Rivers, where vast areas of root cultivations are concentrated.The studied vegetation patches are located between 344 and 2615 meters above sea level.They are developed on different types of substrate, with a range of soil pH between 6.8 to 7.9, and containing various granulometric structures.

Data and analyses
The field study was conducted in 2011.During the study 107 phytosociological relevés were made.The plot size used to sample vegetation was established so as to represent full floristic composition, varying from 25 to 30 m 2 depending on plant density and homogeneity of vegetation cover.For each vegetation patch all vascular plants were recorded.Cryptogams were not noted because of their secondary importance in the segetal communities in the Middle Asia.Plant species were recorded according to the Braun-Blanquet cover-abundance scale [88].Geographical coordinates, elevation above sea level, aspect and slope inclination were noted for each relevé.
All relevés were stored in a database using the JUICE software [89].A TWINSPAN analysis [90] was used to perform the preliminary classification of communities.The data from the relevés showed a clear unimodal response, enabling us to use a detrended correspondence analysis (DCA) with a floristic data set (presence-absence data, no down weighting of rare species) to check floristic-sociological classification and to show relationships between the groups.For ordination, CANOCO for Windows 4.5 was used [91].
Species nomenclature mainly followed Czerepanov [99].Plant material collected during field studies was deposited in the Herbarium of Middle Asian Mountains, hosted in OPUN (Opole University, Poland) and KRA (Jagiellonian University, Poland).
The DCA ordination run for the entire data set clearly segregates the association described as new to science (Brassico campestris-Lamietum amplexicauli) as well as other associations.The reason for this is, of course, the essential differences in the floristic composition and structure of individual phytocoenoses.Only plots closely related in terms of habitat conditions, such as some phytocoenoses of Convolvulo-Cyperetum, Galinsogo-Setarietum and Daturo-Hibiscetum, are not clearly distinguishable one from another.This is probably due to the irrigation of the fields in which they appear and the occurrence of common species of wet habitats such as Plantago major, Polygonum aviculare and Cyperus rotundus.Diagnostic species: Cyperus rotundus.
The Convolvulo arvensis-Cyperetum rotundi association is among those particularly common in Tajikistan.Phytocoenoses dominated by, or featuring a high share of, Cyperus rotundus developed mostly in middle sections of alpine rivers of the study areas, among others, the Syr Darya, Pasrud Darya, Yagnob, Zeravshan, Kafirnighan and Vakhsh Rivers, mostly at altitudes of ca.700-900 m.Convolvulo arvensis-Cyperetum rotundi occurs mainly in maize, potato, tomato, cotton, leek and, rarely, in parsley plantations.The association develops in moist and fertile, brown soils with close to neutral reactions (pH approx.7.3; Fig. 4).Fields are in most cases irrigated.Cyperus rotundus is not always apparently dominant; however, in a few plots, the cover of this diagnostic species exceeds 40%.The mean cover value of Cyperus rotundus is ca.10-20%.In phytocoenosis, which is relatively rich in species, ca.14  Diagnostic species: Hibiscus trionum, Datura stramonium.Plots of this association have been observed spread mainly over the southern Tajikistan and Prisyrdaryan geobotanical regions.They are typified by loose cultivation of maize, cotton, lentils, onions, beans and, sporadically, carrots.The phytocoenoses were recorded within a range of altitudes from ca. 700 to 1000 meters above sea level (Fig. 4).The community prefers warm, deep, brown soils with inconsiderable gravel or sand content.The reaction of the substrate was neutral or slightly alkaline [pH 7.0-7.3(7.7)].Fields are often irrigated.In a single plot, between 10 and 20 species were noted.The average number of species per relevé was 14.The maximum cover of weed species in the phytocoenoses was about 65%, or, in most cases, ca.45%.Besides diagnostic species, this association is characterized by a high share of meadow or pasture species including Cynodon dactylon, Plantago major, and Polygonum persicaria.This is mainly because of the irrigation of the plantations.To the most constant taxa belong Amaranthus retroflexus, Abutilon theophrasti, Convolvulus arvensis, Solanum nigrum, Portulaca oleracea and Xanthium italicum.The diagnostic taxa generally prefer warm sites throughout the area of their occurrence in the east Mediterranean-Irano-Turanian region within medium-height mountainous locations.
The association occurs sporadically in the southern Tajikistan geobotanical region.It prefers medium elevations, that is, altitudes of 800 to 1000 meters above sea level (Fig. 4).The association develops mainly in potato and lentil cultivations.Its phytocoenoses are associated with fertile, relatively dry, neutral or slightly alkaline soils, often with high sand content and quite loose.Between 10 and 20 species were recorded in a single plot (mean approx.15).The phytocoenoses of Setario pumilae-Sorghetum halepensi association are characterized by a relatively high cover of herb layer.The maximum cover of weed species in the phytocoenoses was about 85%.The mean cover of the whole "c" layer was ca.65-70% (Fig. 4).The diagnostic Sorghum halepense has relatively high cover in all plots.To the most abundant and constant species found in phytocoenoses belong Xanthium italicum, Helianthus tuberosus, Echinochloa crus-galli and Cyperus rotundus.Cereal crop species from the Turgenio-Roemerietalia refractae order such as Avena trichophylla or Cirsium incanum were also noted in observed plots.
The association is very distinct from other segetal weed communities noted in Tajikistan (Fig. 3).It is associated mainly with maize, lentil, potato, sunflower, and tomato fields situated at medium elevations within an altitudinal range of 800 to 1180 meters above sea level (Fig. 4).The association develops on relatively dry, sandy soil, or soil with significant stone content or gravel fraction substrates.The soil is neutral or slightly alkaline [pH 7.0-7.5(7.8)],moderately fertile, and sporadically irrigated.Plots of the association are moderately rich in species, containing from 10-24 taxa (mean approx.14).The total cover of weed species in the phytocoenoses rarely exceeds 80%, and in most cases it fluctuates around 60% (Fig. 4).Typical for the observed plots was the relatively significant cover of the diagnostic species Xanthium italicum, which attains an average value of approx.30-35%.Among the species with the highest constancy are Setaria viridis, Galium spurium, Echinochloa crus-galli, Cichorium intybus, Chenopodium album and Convolvulus arvensis.In several plots, due to the irrigation, considerable cover of Cynodon dactylon was found.Also, the Cuscuta campestris which parasitise Xanthium italicum have significant cover in few plots.
The community with Chrysanthemum coronarium is extremely rare in Tajikistan.Plots of this community were found only in one location in the Vakhsh river valley at the altitude of ca.1000 meters above sea level (Fig. 4).It has been noted in Lens culinaris and Solanum tuberosum plantations on deep, brown, loessic and slightly alkaline soil.The substrate was generally dry; however, it is supposed that the field undergoes irregular irrigation.Only 10 species were recorded in the relevés; thus, the association is among the poorest (Fig. 4).The diagnostic taxon has been observed in both plots, with considerable cover of 55-60%.The total cover of weed species in the phytocoenoses does not exceed 65%.The association is characterized by a high proportion of Stellarietea mediae species, e.g.Setaria viridis, Chenopodium album, Amaranthus retroflexus, Sorghum halepense or Cyperus rotundus (Tab.S2, rel.[34][35].Also, taxa typical for cereal crop vegetation from the Turgenio-Roemerietalia refractae order were noted in phytocoenoses (e.g.Anthemis altissima, Avena trichophylla).This is related to the crop rotation cycle and the proximity of cereal and root crops.Diagnostic species: Galinsoga parviflora, Galinsoga ciliata.The association was found in only a few places in Tajikistan, in sandy fields, mainly around Dushanbe in the southern Tajikistan region.Plots of the phytocoenosis were noted at altitudes of ca.1000-1200 meters above sea level (mean approx.1180; Fig. 4).The association was found mostly in potato cultivations.Its phytocoenoses are associated with moderately fertile, mesic dry and neutral (pH 6.8-7.2) brown soils, which contain a high percentage of sand or gravel fractions.The researched plots were species-poor, containing on average approx.13 species in a single patch.The phytocoenoses of Galinsogo-Setarietum are characterized by a relatively high cover of herb layer due to the considerable domination of Galinsoga parviflora, Kochia scoparia or Oxalis fontana.Apart from diagnostic species, plots of this association often include Sonchus oleraceus, Plantago lanceolata, Polygonum persicaria, Trifolium repens and Polygonum aviculare (Tab.1).
The association is the least thermophilous syntaxon of all those recorded in root crops in Tajikistan.It occurs mostly in the Zeravshanian, Hissar-Darvasian and eastern Tajikistanian geobotanical regions at relatively high altitudes, from generally 1900 to 2500 meters above sea level (mean approx.2100; Fig. 4).The association develops mainly in potato cultivations.Its phytocoenoses are associated with unfertile, neutral or moderately alkaline, grey soils and rankers, which are often very stony and loose.Recorded plots were sometimes observed on northern slopes of alpine river valleys (e.g.Yagnob, Pastrud Darya, Iskander Darya) or on northern rock walls.Between 5 and 17 weeds were recorded in a single plot (mean approx.11).The plots of the Brassico campestris-Lamietum amplexicauli association are characterized by a relatively low cover of herb layer.The maximum cover of weed species in the phytocoenoses was about 70%.The mean cover of the whole "c" layer was ca.35% (Fig. 4).Co-occurring species generally represent root-crop weeds (e.g.Chenopodium album, Sonchus oleraceus).However, there is also a relatively considerable share of cereal-crop field species (e.g.Fagopyrum tataricum, Lepyrodiclis holosteoides, Torilis leptophylla).These phytocoenoses are also supported by species typical for ruderal habitats, like Sisymbrium altissimum or Melilotus officinalis (Tab.2).Diagnostic species: Portulaca oleracea.The association of Portulacetum oleracei is among the most widely distributed in Tajikistan.However, within vegetable crops it was found sporadically.Phytocoenoses dominated by Portulaca oleracea developed mostly at middle elevations of river valleys in the southern Tajikistanian and Prisyrdaryan geobotanical regions, mostly at altitudes of ca.750-950 meters above sea level.Portulacetum oleracei occurs mainly in potato plantations.The association develops on moist and fertile, deep, brown soils with a relatively high content of sand or gravel.The substratum is close to neutral (pH approx.7.2-7.5;Fig. 4).Fields are located in sunny places and sometimes irrigated.Portulaca oleracea is always apparently dominant.The cover of this diagnostic species exceeds 60%.The phytocoenoses of the association feature significant total cover of weeds, more than 70%.In phytocoenoses relatively rich in species, ca.14 taxa have been noted on average.Co-occurring species represent segetal (e.g.Echinochloa crus-galli, Chenopodium album, Setaria viridis, Amaranthus retroflexus, Veronica persica) or ruderal (e.g.Melilotus indicus, Malva neglecta, Amaranthus blitum, Cynodon dactylon) vegetation (Tab.3).

Synopsis of syntaxa
Based on this study, we propose the following classification of the weed communities of root crops in Tajikistan: Stellarietea

Discussion
So far, few studies concerning segetal weeds in Tajikistan have been published, and the existing publications were issued quite a long time ago (e.g.[100]).To discover distribution patterns and the species richness of Tajikistan's segetal flora, a reconnaissance field study and a research query were conducted in the years 2008-2010.As a result of the analyses, it was determined that Tajikistan's segetal flora consists of 689 taxa.The most weed-abundant families include Fabaceae, Asteraceae, Chenopodiaceae, Lamiaceae, Boraginaceae and Brassicaceae.The most weed-rich regions of the country are the southwestern areas, i.e. the southern Tajikistanian geobotanical region where over 500 species were observed.Also, the Hissar-Darvasian, Prisyrdaryan and Zeravshanian regions, where approx.350 weed species occur, are also rich in segetal flora.As regards vertical distribution, the largest weed species richness was observed within the range of 800 to 1700 meters above sea level.Due to very extensive agriculture as well as relatively small fields, weed occurrence is frequent outside segetal communities in Tajikistan.Weeds were usually noted in riverbed gravels, screes, wastelands, rushes, xerothermic grasslands and in typical ruderal communities [101].The richness of the segetal communities is clearly visible when the number of species in separate patches of vegetation, with up to 50 taxa per plot in crop cultivations, is considered.The total number of species detected in the data set as a whole is significant.This is relatively rich flora when compared to other crop cultivation areas in the world (e.g.[35,36,39,50,71,102]).
The floristic structure and separateness of the community makes it necessary to distinguish a new association: Brassico campestris-Lamietum aplexicauli.This is one of the most interesting phytocoenoses occurring in the highest elevations occupied by root-crop cultivations in the Pamir Alai Mts (ca.1900-3000 meters above sea level).The association corresponds with another typically mountainous segetal community known from cereal-crop fields of the Middle Asia: Fagopyro tatarici-Lathyretum sativi [83].Both associations have developed on similar soils and have many species in common, such as: Brassica campestris, Fagopyrum tataricum, Lepyrodiclis holosteoides or Torilis leptophylla.However, the cereal association has a clearly narrower range, being restricted to the eastern Pamir.
Another interesting root-crop association is Convolvulo arvensis-Cyperetum rotundi Carretero et Aguilella ex Ninot, X. Font, Masalles et Vigo 2010-2011.This phytocoenosis is apparently related to irrigated fields and has the greatest share in cotton plantations.The association was described as a weed community chiefly formed by geophytes like Cyperus rotundus and Convolvulus arvensis and including other generalist ruderals like Portulaca oleracea, Amaranthus blitum or A. retroflexus [97].
Although it has been suggested that the community develops under a cultivation regime of low intensity, including irrigation, it seems obvious that compared to a more continental climate (e.g.littoral Mediterranean conditions in Spain), in Tajikistan the association needs quite intensive irrigation.It is one of the most widespread segetal plant associations in Tajikistan.Because of the abundant occurrence of Cyperus rotundus it could be compared to Setario ambiguae-Cyperetum rotundi Brullo, Scelsi & Spampinato 2001 from Sicily, which also occurs in alluvial, moist soils within the thermo-and mesomediterranean bioclimatic belts, but generally in citrus groves [45].It could be also compared to Digitario sanguinalis-Cyperetum rotundi Bergmeier 2008, known from sandy or loamy-sandy alkaline soils from citrus cultivations in Crete [103].
As Convolvulo arvensis-Cyperetum rotundi has frequently been found in Europe in ruderal habitats or fields and orchards close to disturbed biotopes, a subassociation characterized by a considerably high share of Kochia scoparia could be distinguished.In researched plots in Tajikistan several relevés are dominated by Kochia scoparia; thus it seems plausible to separate the new syntaxon at the lowest rank as a segetal phytocoenosis closely related to communities from the Atriplicion alliance (e.g.[95,97,[104][105][106]).
Another thermophilous association typical for arable root crop cultivations is Daturo stramonii-Hibiscetum trioni Bagrikova (1996) 1997.It has been recently described from vineyards of Crimea [96] as a species-poor community from the Atriplici-Chenopodietalia albi order.Considering the floristic structure, habitat conditions and climatic circumstances, the plots from Tajikistan are truly comparable to those reported from Crimea.The difference is in cultivated plants, as in Tajikistan the Daturo stramonii-Hibiscetum trioni association was found mainly in plantations of maize, cotton, lentils, onions, and beans, but not of potatoes.Also, the share of Cynodon dactylon is higher here, making the plots similar to Hibisco trioni-Cynodontetum Kolev 1976 described from the Balkans [50].However, this species has broader ecological amplitude in the Middle Asia, is not typical for segetal vegetation and its presence and abundance depends mainly on irrigation and trampling by cattle after harvest of the cultivation crop.Therefore, Cynodon dactylon seems not to be an appropriate diagnostic species for the association or alliance.This species, as well as other C4 grasses, have been reported as diagnostic for the ruderal and sometimes also segetal syntaxa from the Eragrostion cilianensi-minoris alliance typical for warm synanthropic habitats with sandy or gravelly soils.The studies of Čarni & Mucina [107], Kropač [108], Borhidi [109], Sanda et al. [47], Lososova et al. [36] and Němec et al. [110] have revealed the Hibisco trioni-Eragrostietum poaeoidis Soó et Tímár 1957 to be a rare association inhabiting arable fields mainly containing root crops, trampled habitats and recently disturbed synanthropic sites in Central Europe and the Balkans.However, due to a colder and wetter climate, the syntaxon has a higher level of participation of Eurosiberian or Boreal species in comparison to plots found in Tajikistan, where Irano-Turanian and Mediterranean taxa clearly prevail.
Several relevés have been identified as Portulacetum oleracei Felföldy 1942.This is a commonly occurring association throughout the eastern Mediterranean and Irano-Turanian provinces, known from vineyards, lavender, root crops and cotton plantations as well as orchards and vegetable gardens [47,94,96,109,111].In Tajikistan it develops mainly in poorly managed vegetable gardens with the lowest cultivation intensity.In these plots the crop cover is relatively low; thus the total weed cover can attain high values.The Portulacetum oleracei association has a rather insignificant share of ruderal species, such as Malva neglecta, Amaranthus lividus, or A. blitum.The association is confined to sunny places, close to ruderal habitats, with sandy substrata, often well supplied with water (irrigation) and nitrates.
Equiseto arvensi-Xanthietum italici Kolev 1976 develops on moderately fertile, often sandy or gravelly soils.The association was described from sandy fields in Bulgaria [50].Despite the absence of Equisetum arvense, which has a different ecological amplitude in Tajikistan (occurring mainly in bogs and riverside forests), plots with abundant occurrence of Xanthium italicum have been identified as Equiseto-Xanthietum italici because of floristic and habitat similarities to phytocoenoses known from the Balkans.The association shows a relative preference for the driest locations; however, it has also been observed in plots under an irrigation regime.Xanthium italicum prefers such unstable and changing moisture conditions.The species is regarded as diagnostic to associations typical for inundated river alluvials such as Xanthio strumarii-Bidentetum Timár 1947 from the Bidentetea class [47].
Another association occurring on relatively dry substrates is Setario pumilae-Sorghetum halepensi Ştefan et Oprea 1997.It is known from Romania and adjacent areas where it grows in irrigated fields, mainly root crops.In Tajikistan the association develops sporadically in the southern Tajikistanian geobotanical region.As in Europe, it is a rather species-poor association apparently dominated by grass species such as diagnostic Sorghum halepense or Setaria pumila.There is still a need to explore the communities of Sorgum halepense in more detailed studies and find its relation to other associations, such as Chondrillo junceae-Sorghetum halepensis Kolev 1976 (described from cereals in the Balkans [50]) or Hibisco trioni-Sorghetum halepensi (described from Dalmatia [112]).Also, Galinsogo-Setarietum merits further research in Tajikistan focusing especially on the syntaxonomical position of this community.Other root-crop associations play a minor role in segetal habitats of Tajikistan; however, they significantly contribute to the diversity of agrocoenoses.There is still a need for further research in root-crop communities of Tajikistan and the Middle Asia.Some of the above-mentioned syntaxa (e.g.Brassico-Lamietum or Convolvulo-Cyperetum) are significantly diversified in terms of floristic structure; hence, after collection of more data or enlargement of the survey area, it would seem possible to describe new syntaxa with at least subassociation rank.Taking more relevés may help to classify the community of Chrysanthemum coronarium and to discover its relation to Asphodelo fistulosi-Hordeetum leporini O. Bolòs 1956 chrysanthemetosum coronarii, Resedo albae-Chrysanthemetum coronarii O. Bolòs et Molinier 1958 or Malvo parviflorae-Chrysanthemetum coronarii Ferro 1980 [113][114][115].Chorological analyses and conservation considerations will also be of great importance in discovering the present distribution patterns of weed flora of Tajikistan.