PLANT COMMUNITIES IN ARABLE FIELDS OF THE SKIERBIESZÓW LANDSCAPE PARK

Floristic research on segetal communities was carried out in 2000 on arable fields in the Skierbieszów Landscape Park and its protected zone. Three communities of segetal weeds in cereal crops, and two communities of segetal weeds in root crops were separated in the arable fields of the Skierbieszów Landscape Park. The community Vicietum tetraspermae typicum commonly occurred in cereal crops on brown soils developed from loess soils. The community Echinochloo-Setarietum, which belongs to root crops, was noted in the same habitat. The greatest richness of species was found in Consolido-Brometum and Lamio Veronicetum politae, with the average of 25 species in one record. Both communities were abundant in rare segetal species which are considered to be endangered in our country: Adonis aestivalis, Euphorbia exigua, Lathyrus tuberosus, Muscari comosum, Thlaspi perfoliatum, Veronica polita, Agrostemma githago.


INTRODUCTION
The common use of herbicides and high doses of fertilizers trigger the disappearance of many segetal communities.This concerns especially the communities growing in very poor and acid, or calcerous soil.Species distinctive for these environments disappear, and nitrophilous species thrive.Impoverished communities are formed with one or two species clearly dominating (A n i o ł -K w i a t k o w s k a , 1990; T r ą b a and Z i e m i ń s k a , 2006).For a long time, naturalists have been paying attention to the necessity to retain diversity of species in segetal communities (S i c i ń s k i , 2001).M e d w e c k a -K o r n a ś (1986) notes that rare species and protected species can survive only if their habitats and environments within plant communities are protected.Protection of biodiversity is easier in protected areas, such as landscape parks.Agricultural management is limited there, which gives a better opportunity to counteract the threats.The aim of this study is to characterise the diversity of species of segetal communities in cereal crops and root crops in the Skierbieszów Landscape Park and its protected zone.
The aim of the study is to separate and describe weed species in cereal crops and root crops in brown soils and rendzinas of the Skierbieszów Landscape Park and its protected zone.The research that was carried out allows to distinguish endangered and rare species of segetal flora in the investigated area.Detailed studies of segetal communities were not conducted in this area.Fragmentary studies on the plants of the Skierbieszów Landscape Park were made by F i j a ł k o w s k i and A d a m c z y k (1990).

MATERIALS AND METHODS
Floristic research on segetal communities was carried out in 2000 on arable fields in the Skierbieszów Landscape Park and its protected zone (Fig. 2) on brown soils and rendzinas.Moreover, in May 2001 the list of segetal flora species was supplemented with typically spring species.The type and kind of soil and its agricultural usability were determined on the basis of soil-agricultural maps at a scale of 1:5000.In cereal and root crops, 110 phytosociological records were taken using the Braun-Blanquet method (1964).Species nomenclature followed M i r e k et al. (2002) and the classification of communities was based on the system proposed by M a t u s z k i e w i c z (2002).The records were grouped into communities of weeds, which were subsequently put into floristic tables (Tabs 1-2).In the tables, the degree of constancy (S) and the cover coefficient (D) were calculated for specific taxons; only these species were included which reached at   Explanation:* Bwl-brown soil formed from loess, R -rendzinas, 1-very good wheat complex, 2 -good wheat complex, 3 -defective wheat complex, Ch -characteristic species.
cd. Table 1 least once constancy II in one community.Soil samples were collected from the patches of plant communities in order to determine the pH of the surface layer of the soil.The results of this analysis were put in the headings of the tables (Tabs 1, 2).The investigated areas are shown in Fig. 2.

Characterisation of the investigated area
The Skierbieszów Landscape Park is located in the Lublin province and occupies the eastern part of the province, called Wierzchowina Grabowiecka or 'działy Grabowieckie', which apart from Roztocze belongs to the most interesting subregions of Eastern Poland, as far as nature and landscapes are concerned.The park was set up in 1995 and includes the whole area of Skierbieszów commune and parts of the following communes: Stary Zamość, Izbica, Sitno, Grabowiec, Miączyn, Kraśniczyn, and Krasnystaw, with a total area of 35 488 ha, including the protected zone 47 967 ha (F i j a ł k o w s k i , 1996).According to geobotanical division of the Lublin region, the area of the Skierbieszów Landscape Park belongs to the Lowland-Highland Province, Central European, Baltic Division, Central Highlands Division, Land: Lublin Highland (S z a f e r , 1959).
The areas surrounding Skierbieszów are known in geobotanical literature for beech forests on the northeast boundaries (F i j a ł k o w s k i and A d a m c z y k , 1990).Another characteristic feature of the area is the occurrence of swards and xerothermal thickets.The arable sites of the park consisted of 145 weed species, including 40 protected species.The main branch of human activity in the investigated area is agriculture.Therefore, arable lands account for the greatest part of the Park and its protected zone.Arable lands cover almost 80% of the area (Census of Agriculture 2003) and can be found mainly in the following communes: Grabowiec, Sitno, Miączyn, whereas in the communes: Stary Zamość, Skierbieszów, Izbica, arable lands cover a smaller part of the area.The greatest area in the structure of arable lands is covered with arable soils.There are small areas of meadows and pastures.The high quality of the area for agricultural production in the landscape park (F i j a ł k o w s k i , 1990) provides great opportunities to cultivate high demand crops, such as wheat and root crops; the former takes up 66% of the cultivated area; potatoes and beet cover slightly smaller areas (Census of Agriculture 2003).

RESULTS AND DISCUSSION
In the area of the Skierbieszów Landscape Park and its protected zone, three communities of cereal crops and two communities of root crops were distinguished.The community Vicietum tetraspermae is the most common in the investigated area.It occurred on loess soils that belong to good wheat and defective wheat complex.The pH of the surface layer of the soil ranged from pH 4.1 to 7.0 (Tab.1).The reaction of most of the analysed soil samples was acidic or slightly acidic (O b o j s k i a n d S t r ą c z y ń s k i , 1995).
Vicia tetrasperma occurred most frequently in the community, another species -Bromus secalinus -was found very rarely (Tab.1).
The Vicietum tetraspermae typicum community developed mainly in winter wheat, less frequently in rye canopy.The community consisted of 82 weed species.An average of 22.9 taxons was noted in one record.Much greater floristic richness was found in an analogical community in the protected zone of Roztocze National Park (Z i e m i ń s k a -S m y k , 2006), where about 30 species were noted in one record.The same community that was distinguished by S k r z y c z y ń s k a in the area of 'Wysoczyzna Kaluszyńska' consisted of a smaller number of species (S k r z y c z y ń s k a and S k r a j n a 2004), with an average of 18 species in one record.
The Vicietum tetraspermae typicum community frequently occurs in the Lublin region (F i j a ł k o ws k i , 1996; K u c h a r c z y k , 1999; Z i e m i ń s k a -S m y k , 2006), and in the whole country (A n i o ł -K w i a t k o w s k a , 1990; S k r z y c z y ń s k a , 1994).It is replaced with the community Echinochloo-Setarietum in root crops (A n i o ł -K w i a t k o w s k a , 1990; K u c h a r c z y k , 1999).
Within the typical Vicia tetrasperma community, a variant was separated that occurred very frequently -Apera spica-venti, which developed in environments similar to a typical community.However, this community was very poor floristically because on the average 19.8 taxons were observed.It occurred most frequently in Majdan Skierbieszowski, Drewniki, Osiczyna, Udrycze, Pańska Dolina, Nowa Lipina and Drewniki.The species characteristic for the community had low cover coefficients and degrees of constancy (Tab.1).The physiognomy of the community was mainly built by Apera spica-venti, with the cover coefficient of over 3800.Other perennial species that  k a , 1990).
The Consolido-Brometum community that belongs, like Vicietum tetraspermae, to the Aperion community developed in the investigated area in rendzinas of the defective wheat complex.The pH of the surface layer of the soil was neutral -within 6.7-7.0.The community was found mainly in winter wheat canopy and was represented by 85 weed species.It was floristically rich, with an average number of 25.9 taxons in one record.The community was observed in Kryniczki, Chomęciska Małe, Borowina Starozamojska and Orłów Murowany.Among the most characteristic species, Consolida regalis was the one that was found most frequently (Tab.1), but Bromus secalinus occurred very rarely.From the Aperion community, the following taxons were noticed: Apera spica-venti, Vicia hirsuta, and less frequently V. sativa.In the calciphilous Caucalidion community, attention should be paid to Melandrium noctiflorum, Agrostemma githago, Avena fatua, Euphorbia exigua, Lathyrus tuberosus, and from the remaining group -Muscari comosum.They belong to rare calciphilous species in segetal flora of our country (F i j a ł k o w s k i , 1996; S i c i ń s k i , 2001; W a r c h o l i ń s k a , 1998).Over a dozen plants of this species were found in the area of Skierbieszów Landscape Park (fallow land and adjacent arable fields in Borowina Starozamojska).
The Avena fatua community infested mainly spring crops (mixture, oats, barley) in rendzina and brown loess soils with a slightly acidic soil pH (Tab.1).This community was floristically poor, with an average of 18.8 species in one record (66 species on average).The community was observed in the following places: Orłów Murowany, Chomęciska Małe, Kryniczki, Suchodębie, Pańska Dolina.The community had features that place it between the Caucalidion and Aperion communities.This community was dominated by Avena fatua, from the calciphilous Caucalidion community, and reached high constancy (V) and the cover coefficient of about 1980.From the acidophilous Aperion community, Apera spica-venti and Vicia hirsuta occurred quite frequently.From the Polygono-Chenopodietalia suborder, Setaria pumila was the most common.The community with similar floristic contents, described as an impoverished community from the Caucalidion community, is known from a study of W n u k et al. (1989).The association of Avena fatua in spring crops was described by H o ł d y ń s k i (1991) in Żuławy Wiślane.
The Echinochloo-Setarietum community was found in similar environments as Vicietum tetrasper-mae typicum.It occurred commonly in the area where sugar beet, beetroot, and potato were cultivated.74 species of weeds were noticed in the community, with the average of 22.4 taxons in one record.The community was found in the following places of the Park: Zabytów, Sulmice, Udrycze, Stryjów, Cieszyn, Wierzba and Majdan Sitaniecki.The most characteristic species in the community were: Echinochloa crus-galli and Setaria pumila (Tab.2).From the Polygono-Chenopodietalia suborder, a very important role in crop infestation was played by Chenopodium album.and Matricaria maritima ssp.indora as well as Myosotis arvensis from Stellarietea mediae.
The Echinochloo-Setarietum community commonly occurs in root crops in the Lublin region ( The variant Echinochloo-Setraietum with Galinsoga parviflora had a high contribution of Galinsoga parviflora and Echinochloa crus-galli (Tab.2).This variant differed from a typical community in the high contribution of species such as Chenopodium album and Stellaria media (Tab.2).Phytocoenoses of this type were observed in Stara Wieś, Stryjów, Zabytów, and Czajki in potato and sugar beet canopy.There was significantly lower richness of species in the community than in a typical variant, in one phytosociological record 18.6 species of weeds were observed, with a total number of 49 species.
A community with similar floristic contents was observed by Towpasz and Barabasz-Krasny in the area of Czarnorzęki-Strzyżów Landscape Park (2006) and S k r z y c z y ń s k a and M a r c i n i u k from Siedlce (2003).
The Lamio-Veronicetum politae community is a representative of eutrophilous alliance Polygono-Chenopodion.In the area of the Park it occurred mainly in rendzinas of the defective wheat complex with neutral reaction (Tab.2).The community occupied small areas in Kryniczki, Borowina Starozamojska and Chomęciska Małe.The total number of 49 weed species was observed in the community, with the average number of species in the relevé -25.2 taxons.A characteristic species in the community -Veronica polita -occurred often and grew thickly (V degree of constancy); the second taxon -Lamium amplexicaule -was more rarely encountered.In the community, numerous rare calciphilous species were observed such as: Euphorbia exigua, Aethusa cynapium, Melandrium noctiflorum.The physiognomy of the community was determined by Matricaria maritima ssp.indora, Chenopodium album, and Cirisium arvense (Tab.2).Lamio-Veronicetum politae was described by H o ł d y ń s k i (1991), K u c h a r c z y k (1999) as well as T r ą b a and Z i e m i ń s k a (1994).This community undergoes significant changes caused by anthropopression, which result in the elimination of species with narrow ecological amplitude, such as the species characteristic for this community (F i j a ł k o w s k i , 1996; S i c i ń s k i 2001; W a r c h o l i ń s k a , 1998).

CONCLUSIONS
1. Three segetal communities were separated in cereal crops, in rendzinas and loess soils of the Skierbieszów Landscape Park.Two segetal communities were separated in root crops, in rendzinas and loess soils of the Skierbieszów Landscape Park.2. Vicietum tetrsperma typicum was the most frequently found community in cereal crops in loess soils in the investigated area.The Echinochloo-Setarietum community was found in root crops on the same soils.3. The greatest richness of species was found in Consolido-Brometum and Lamio Veronicetum politae, 25 species on the average.Both communities were abundant in rare segetal species which are considered to be endangered in our country; they were as follows: Adonis aestivalis, Veronica polita, Thlaspi perfoliatum, Euphorbia exigua, Lathyrus tuberosus, and Muscari comosum.These phytocoenoses and their habitats should be protected.
F ij a ł k o w s k i , 1996; K u c h a r c z y k , 1999; T r ą b a and Z i e m i ń s k a , 2006) and in the whole country (A n i o ł -K w i a t k o w s k a , 1990, H o ł d y ń s k i , 1991, R z y m o w s k a and S k r z y c z y ń s k a , 2007).

Table 2
Floristic diversity and species richness in root-crops communities in Skierbieszów Landscape Park.