Vegetation of uncultivated arable land under different ...

Agriculture, Ecosystems and Environment 92 (2002) 225–233

Vegetation of uncultivated arable land under different management in Finnish and Russian Karelia Juha Jantunen∗ , Kimmo Saarinen Karelian Environment Institute, Lääkärintie 15, FIN-55330 Tiuruniemi, Finland Received 16 March 2001; received in revised form 21 August 2001; accepted 24 August 2001

Abstract The vegetation of uncultivated arable land under modern, cereal/forage cropping in Finnish Karelia (n = 10) and old fashioned hay cultivation in Russian Karelia (n = 10) was compared in terms of their species composition. The plots (n = 160) were located in field margins, fallow fields and non-intensively used or abandoned hay fields unploughed over the last five years. In the TWINSPAN classification, the Finnish and Russian sites ended up in their own groups, with the exception of two sites. The mean numbers of taxa were only slightly higher in Russia, but there were major differences in species composition. According to indicator species analysis, the Finnish sites were characterised by species of early successional stages and nutrient rich, abandoned fields, such as Epilobium angustifolium, Sonchus arvensis, Elymus repens, Anthriscus sylvestris and Tussilago farfara. The Russian sites were characterised by species adapted to more stable conditions (Ranunculus acris, Luzula multiflora), cultivated species (Dactylis glomerata, Alopecurus pratensis) and species benefiting from hay cultivation (Leucanthemum vulgare, Galium album). The number and cover of monocotyledon species, sedges in particular, was higher in Russia, the cover of perennial weeds being higher in Finland. © 2002 Elsevier Science B.V. All rights reserved. Keywords: Fallow land; Field margins; Finland; Hay fields; Russian Karelia; Vegetation

1. Introduction The border between Finland and Russia offers a unique opportunity for evaluating human impact on agricultural environments. Large areas of Karelia across the border were under similar management regimes while belonging to Autonomous Finland (1809–1917) and Finland (1917–1944), but after the Second World War, Karelia was divided by the present Finno–Russian border. Since then, the history of agricultural management differed between adjacent areas in Finnish and Russian Karelia. ∗ Corresponding author. Tel.: +358-5-432-8632; fax: +358-5-432-8625. E-mail address: [email protected] (J. Jantunen).

According to agricultural statistics for Finland (National Board of Agriculture, 1940–1998) and Russian Karelia (Sunkin, 1967; Koboev, 1980, 1985; Volkov, 1993, 1998, 1999), there are five major differences in agricultural management between the two countries. 1. Decrease in field area in Finland. In the province of North Karelia (S.E. Finland), the field area has decreased from 139,000 to 83,300 ha between the 1960s and 1998 due to the centralisation of production and the depopulation of the countryside (Pykälä and Lappalainen, 1998). During the same period in the Republic of Karelia, the field area has increased from 66,000 to 75,000 ha. 2. Extensive cultivation of cereals in Finland. Since the 1960s, 30–40% of the total field area has been

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J. Jantunen, K. Saarinen / Agriculture, Ecosystems and Environment 92 (2002) 225–233

under cereals in North Karelia. In Russian Karelia, cereals cultivation practically ceased during the 1950s, covering 0–6% of the total field area. Correspondingly, the area of fields growing forage plants has varied between 50–60% on the Finnish side, and between 80–90% on the Russian side. 3. Efficient use of fertilisers in Finland (Raatikainen, 1986). Between 1980 and 1995 80–100 kg/ha nitrogen were applied annually. In Leningrad region, chemical nitrogen fertilisers applied at the rate of 70–100 kg/ha during the 1980s, have decreased to 15–30 kg/ha by 1998 (Regional Council of South Karelia, 2000). In Russia, manure has been the most common fertiliser during the last few decades. 4. Efficient use of pesticides and herbicides in Finland (Mukula and Ruuttunen, 1969). On average, 2 kg/ha of pesticides were used during the 1980s, but since then the amount has decreased due to new production methods and more effective compounds (Hynninen and Blomqvist, 1995; Pykälä and Lappalainen, 1998). In Russian Karelia, the use of plant-protective chemicals has been sporadic (Regional Council of South Karelia, 2000). 5. Large area of fields with underground drainage in Finland. Since the 1940s, the total area of fields with underground drainage has increased from 5 to 53% of the field area. The majority of Russian fields are still drained by open ditches and there has been little if any renovation of the old underground drainage network in Russian Karelia since the 1940s (Isachenko, 1996). Agricultural practices in Finland have included more intensified methods than in Russian Karelia. The floral and faunal diversity on arable land was concentrated on uncultivated and little used areas which have been degraded by farming methods. Modern agriculture has caused several problems for species on arable land. According to Jennersten et al. (1997), these are: (1) the loss of habitats including semi-natural grasslands and smaller, interstitial areas of uncultivated land within the arable landscape (Alanen, 1996; Marttila et al., 1999); (2) a decrease in habitat quality, e.g. due to high chemical inputs (de Snoo and van der Poll, 1999); (3) increased isolation and reduced dispersal between habitats (Eriksson, 1996); (4) reduced gene flow between communities (Frankham, 1995) and (5) decreased interspecific relationships, e.g. between

plants and insect pollinators (Pekkarinen et al., 1987). The species composition in marginal areas was compared under modern cereal and forage cultivation in Finland and old fashioned hay cultivation in Russian Karelia. The aim was to study whether large-scale differences in agricultural practices had any effects on the vegetation of uncultivated or little used arable areas.

2. Methods The study was carried out in the border district of Finland and Russia (Fig. 1). The whole study area belongs to the southern boreal vegetation zone (Ahti et al., 1968), has similar climatic conditions (Alalammi, 1988) and is located on the east Fennoscandian bedrock, forming a natural unit (Kotiranta et al., 1998). The northern part of the area belongs to the regional soil fertility zone, the so-called Sortavala grove district, which was less pronounced on the Finnish side (Kalliola, 1973). A total of 20 field areas were included in the study. All fields surrounded by ditches were located either on flat ground or on slight slopes. All the sites in

Fig. 1. The location of the study area (A) and sites (B) in the border district of Finland and Russia.


Finland (n = 10) were divided into fields of different cultivated species and fallow fields. The Russian sites (n = 10) comprised hay fields, except for one site, which was partly under cereals. Seven hay fields were managed by annual mowing with ploughing and sowing at intervals of 5–10 years, and three of the sites had been abandoned. The mean area of the sites was 7.2 ha in Finland, 12.0 ha in Russia. The vegetation data for each site were collected on eight 2 m × 2 m sample plots. The plots (n = 80 + 80) were located in uncultivated parts of the site which had not been ploughed during the last 5 years. In Finland, plots represented field margins (24), annually mown old fields (12) and fallow fields (56). In Russia, plots were located along field margins (18) and in annually mown (38) or abandoned hay fields (24). The plots were studied in July between 1997 and 1999. Finnish and Russian sites formed comparative pairs, and the members of each pair were studied during a 4 day period. The abundance of each species was estimated by projection cover using a percentage scale (0–100%), their taxonomy as defined by Hämet-Ahti et al. (1998). Similarities between sites were studied by the divisive and polythetic method, TWINSPAN (two-way indicator species analysis; Hill, 1979). TWINSPAN analyses the data based on presence/absence of “pseudospecies”, which are numbered 1–5, representing classes of abundance. The ranges of the abundance were defined by cut levels of 0, 2, 5, 10 and 20% in the analysis. Pseudospecies Vicia cracca 5, for example, was present in plots where the cover of the species was ≥20%. Taxa indicating the Finnish and Russian agricultural areas were determined by indicator species analysis (Dufrene and Legendre, 1997). The method combines information on the concentration of species abundance and the faithfulness of the occurrence of a species in a particular group in either Finnish or Russian sites. It produces indicator values for each species in the groups. The indicator values, ranging from zero (no indication) to 100 (perfect indication), were tested for statistical significance using a Monte Carlo technique. The effects of agricultural management were characterised by eight groups of taxa: (1) monocotyledons as a whole, with further division into (2) graminoids (Poaceae) and (3) sedges (Cyperaceae), (4) dicotyledons as a whole with further division into (5) annual and (6) perennial weeds, (7) grazing-tolerant species

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and (8) traditional grassland species. Weeds included annual taxa (21 observed), except for Rhinanthus, Euphrasia and Melampyrum, which are not usually considered as weeds, and nine perennial taxa, which constantly inhabit fields and other ploughed sites (Ellenberg, 1988; Hämet-Ahti et al., 1998). Grazing-tolerant species were adapted to grazing and mowing by their growth form (Grime, 1979; Oksanen and Ranta, 1992). The group included 21 species with rosettes and prostrate forms. Traditional grassland species (nine observed) were used for characterising the quality of habitat, as these species indicate long-term grazing, hay making and old settlement (Pykälä et al., 1994). They have become rare in Finland due to a lack of traditionally managed pastures and meadows. The summarised number and cover of species in the groups were compared between Finland and Russia by the Mann–Whitney U-test.

3. Results In the TWINSPAN classification, Finnish and Russian sites were clustered in different groups, except for two sites (Fig. 2). At the third division level, the sites were classified into six groups with regard to the intensity of cultivation. Group 0 consisted of intensively cultivated sites, and species benefiting from ploughing, such as Elymus repens and Sonchus arvensis, were more abundant than in the opposite group. In group 00, the only Russian site was the one partly under cereals where the use of manure was observed. Group 1 consisted of older hay or fallow fields. Two of the Finnish sites in group 1 were mown annually. The species composition in Russian sites of group 11 resembled semi-natural grasslands, probably due to long-term annual mowing as the only management method. The average number of species in sites of groups 0 and 1 was 44.3 (S.D. = 10.6) and 51.6 (S.D. = 5.8), respectively. The total number of taxa in Finnish sites was 131 and in Russian sites 134, 98 of which were found in both countries (Table 1). The graminoids had the highest cover in both countries. Phleum pratense (7.9%), Agrostis capillaris (7.9%) and E. repens (6.3%) had the highest mean cover in Finnish sites, Deschampsia cespitosa (14.3%), P. pratense (11.4%) and Alopecurus pratensis (7.2%) in Russian sites. According to the

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Fig. 2. TWINSPAN classification of Finnish and Russian Karelian fields as regards the vegetation in uncultivated areas. The names of species are abbreviated to the first four letters. Numbers after names refer to cover cut levels. Numbers in paranthesis indicate the presence of species in groups of a particular division. Table 1 Taxa of uncultivated arable land in Finnish (n = 10) and Russian Karelia (n = 10)a Group

Epilobium angustifolium Sonchus arvensis Equisetum sylvaticum Urtica dioica Myosotis arvensis Hieracium umbellatum Tussilago farfara Ranunculus repens Gnaphalium sylvaticum Linaria vulgaris Anthriscus sylvestris Geranium sylvestris Betula pendula Rumex acetosella Elymus repens Lathyrus pratensis Rumex acetosa Aegopodium podagraria Achillea millefolia Trifolium pratense Viola tricolor

pW pW aW pW G G pW

G pW

G G aW

Occurrence

Abundance

FIN

RUS

9 7 7 6 5 4 5 10 3 3 9 5 3 4 9 10 6 6 10 7 3

3 1 1 1 1 1 2 9 1 0 7 3 1 2 8 10 5 5 8 9 1

FIN 3.93 0.47 1.33 0.94 0.09 0.63 1.77 4.19 0.09 0.35 2.04 0.48 0.39 1.08 6.33 5.38 0.73 5.71 3.03 3.45 0.15

Indicator values RUS

FIN

RUS

0.11 0.03 0.01 0.01