Does cattle movement between forest pastures and fertilized grasslands affect the bryophyte and vascular plant communities in vulnerable forest pasture biotopes?
Tuomo Takala a,*, Jasmiina Haverinen a,1, Eeva Kuusela a, Teemu Tahvanainen a,
Jari Kouki b aUniversity of Eastern Finland, Faculty of Science and Forestry, Department of Biology, Finland bUniversity of Eastern Finland, Faculty of Science and Forestry, School of Forest Sciences, Finland
A R T I C L E I N F O
Received 31 May 2014
Received in revised form 21 November 2014
Accepted 3 December 2014
Available online 9 January 2015
EU agri-environmental program
Semi-natural rural biotope
A B S T R A C T
The intensification of agriculture has led to a dramatic decrease in traditional forest pastures in Northern
Europe. Furthermore, the remaining forest pastures have often lost their typical characteristics due to eutrophication and forestry practices. We investigated whether the common management practice of fencing forest pastures within the same enclosures as fertilized grassland pastures leads to eutrophication and the consequent decline of bryophyte and vascular plant diversity in Finnish forest pastures, given that when cattle can freely roam between the fertilized grassland pastures and unfertilized forest pastures, nutrients are transported to the forest pastures in the feces and urine of the grazing animals. We found that grazing led to higher electrical conductivity and potassium (K) levels in the forest pastures (n =18) compared to the background levels in adjacent non-grazed forests (n =18).
Vascular plant species richness and diversity (Shannon’s entropy)were higher and community structures different in the forest pastures compared to the adjacent forests. Highest species richness was observed in the forest pastures that were unconnected to fertilized grasslands (n =7). Connection here refers to the situation where cattle can access both forest pasture and adjacent fertilized grassland simultaneously.
Furthermore,many species indicative of valuable semi-natural pasture biotopeswere found only in these traditionally managed forest pastures. In contrast, bryophyte species richness did not differ between the forests and the two types of forest pastures. Moreover, bryophyte communities largely overlapped between the forests and the forest pastures. Our results indicate that even if the forest pastures connected to the fertilized grasslands sustain plant communities that are characteristic of unfertilized semi-natural forest pastures, the conservational quality and diversity of vascular plant communities in particular may be reduced in comparison to the forest pastures without grassland connection. This decline can, at least partially, be caused by the transport of nutrients to the forest pastures and, hence, we recommend that forest pastures are not connected with fertilized grasslands. ã 2014 Elsevier B.V. All rights reserved. 1. Introduction
In Finland, forest pastures were classified as endangered in the first assessment of threatened habitat types in 2008 (Schulman et al., 2008). From the 1950s to the present, the total area of forest pastures has decreased byover 99%, as fertilized grassland pastures established on cultivated land were increasingly used for forage production and as pastures (Schulman et al., 2008). Furthermore, the quality of the remaining forest pastures is often low because of intensive forestry and eutrophication (Schulman et al., 2008). The decrease in area and quality has affected all Finnish semi-natural (traditional) rural biotopes and, as a consequence, numerous species dependent on these environments have become threatened (Rassi et al., 2010).
The effects of cattle grazing on biodiversity are generally positive in productive habitats of Northern Europe (Olff and Ritchie, 1998; Proulx and Mazumder, 1998). However, * Corresponding author. Tel.: +358 44 9118160; fax: +358 13 251 3590.
E-mail addresses: firstname.lastname@example.org (T. Takala), email@example.com (J. Haverinen), firstname.lastname@example.org (E. Kuusela), email@example.com (T. Tahvanainen), firstname.lastname@example.org (J. Kouki) . 1 Present address: University of Eastern Finland, Faculty of Science and Forestry,
Department of Biology, Joensuu Campus, Yliopistokatu 7, P.O.Box 111, FIN-80101,
Joensuu, Finland. http://dx.doi.org/10.1016/j.agee.2014.12.005 0167-8809/ã 2014 Elsevier B.V. All rights reserved.
Agriculture, Ecosystems and Environment 201 (2015) 26–42
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Agriculture, Ecosystems and Environment journa l homepage: www.e lsevier .com/ locate /agee understanding the effects of different management practices is essential for a comprehensive assessment of biodiversity patterns in semi-natural biotopes (Klimek et al., 2007). The fencing of seminatural forest pasture and fertilized grassland pasture into the same enclosure is one of the controversial practices generally thought to cause eutrophication in the forest pasture (Pykälä, 2001), although this practice is not permitted in forest pastures subsidized via European Union (EU) agri-environmental aid. If substantial harmful effects arise, the recommended management approach is to maintain separate enclosures in the forest pastures and fertilized grasslands. At the same time, however, the management of forest pasturesmust be practicable for the farmers and provide sufficient quality for grazing animals. Otherwise there is a risk that forest pastures will be abandoned and this will lead to a further decline in the area of semi-natural rural biotopes.
In Finland, the recommended stocking rates per hectare for a 120 day annual grazing period range from 2.5 to 7.5 (depending on cattle type) in fertilized grasslands and from 0.05 to 0.8 in forest pastures (Salminen and Kekäläinen, 2000). If the stocking rate in an enclosure that comprises both forest pastures and fertilized grassland pastures is determined by the productivity of the grassland, then there is a risk that the grazing intensity will be too high and potential eutrophication in the forest pasture is likely, as the free-roaming cattle will transfer nutrients in the urine and manure from the highly-productive fertilized grasslands to lowproductive unfertilized forest pastures (Pykälä, 2001; Uytvanck et al., 2010). It is worth noting that in practice, farmers adjust grazing intensity and grazing periods in accordance with seasonal weather conditions, prevailing herd sizes on their property and on other practical considerations rather than on official guidelines.