Agricultural land abandonment and biodiversity

15 May 2013 | Article
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Rural landscape constantly changes replying to human demands and socio-economic challenges. Farming practices in fertile and accessible land, usually lowlands, are increasingly intensified, while mountains’ farming systems become marginalized and abandoned. A two-year project lead by University of Ioannina, Greece analysed the impact of agricultural abandonment on landscape structure, vegetation and farmland birds in South-Eastern Europe. The 72 sites in the Balkans were part of the research, 12 in Albania and 20 in Bulgaria, Croatia and Greece.

Europe's countryside is characterized by rich cultural landscapes’ diversity that has been shaped by traditional land use practices. Different studies reveal a dynamic pattern of succession stages’ impacts on biodiversity, but the general trend shows a decline of diversity due to the loss of habitat heterogeneity. Species richness is higher in open habitats or farmlands, while shrublands host fewer species, but sustain several endemic. The effects of abandonment differ among species, depending on their ecological niches.

A research project “Impact of agricultural abandonment on landscape structure, vegetation and farmland birds in SE Europe” (2010-2012), funded by SEE-ERA.NET PLUS was coordinated by the University of Ioannina, with the participation of the Agricultural University of Tirana, the University of Vienna , the Bulgarian Academy of Sciences and the University of Zagreb.

72 sampling sites were classified by forest encroachment representing the abandonment gradient. The occurring habitat types were mapped based on current imagery, using a standardized protocol for ecological mapping and cartographic interpretation. Woody plants were sampled using a modification of EBONE sampling methodology. Birds were sampled using the point count method in 6 - 9 circular plots that were systematically located within each site. All birds seen or heard within each plot for 5 minute interval were recorded twice per year in 617 sampled plots. Sampling resulted in a total of 14,456 individuals of 66 passerine bird species, out of which 21 are of European conservation concern. The bird communities were negatively affected by land abandonment all over the Balkans, as a statistically significant reduction in species number was noted in the whole study area.

The study area in Albania included the southern part of the country, along Vjosa River and the Korça Region. A total number of 78 woody plant species and 57 passerine bird species, with 1,363 individuals were identified, out of which 20 species are of European conservation concern. Results from Albania show that agriculture land abandonment does not affect bird communities in terms of Simpson diversity index. The abundance of different woody land cover categories showed no significant change. Bird species such as Coruvus corone, Carduelis carduelis and Coturnix coturnix have been mostly sampled in the highly woody plant covered sites. Emberiza cirlus, Garulus grandarious, Galerida cristata, Lanius collurio and Luscinia megarhynchos are relatively more frequent in sites with less than 50% woody plant coverage. Passer domesticus was much more sampled in the third land cover category, whereas Passer montanus and Pica pica were mostly frequent in sites slightly covered by woody vegetation.

The effect land abandonment has on passerine bird communities is considerable. Open habitat species seem to be the most sensitive and affected by the habitat loss. Open habitat and shrubland Mediterranean species are considered prone to lose their distribution range under current landscape dynamics in Western Europe.

Traditional, low-intensity agricultural practices are known to result in landscape heterogeneity which affects species richness. One of the recommendations would be the implementation of policies that would motivate people to live in remote areas and apply traditional land use practices. Possible activities could be the promotion of biological farming the establishment of a local products market, and subsidies policy towards traditional extensive farming practices. They should be included in the priorities of agricultural policy for farmland bird diversity conservation in Greece, as local extinction and reduction of abundance of birds characteristic for these cultural landscapes is expected to grow as land abandonment continues. In any case caution should be taken when applying policies that promote landscape heterogeneity, as fragmentation beyond a threshold could favour cosmopolitan species against species that require large areas of continuous habitat .

Prepared by Spase Shumka and Mirjan Topi, PPNEA

References:
1. Farina, A., 1997. Landscape structure and breeding bird distribution in a sub-Mediterranean agro-ecosystem. Landscape Ecology 12, 365–378.
2. Edenius, L., Sjoberg, K., 1997. Distribution of birds in natural landscape mosaics of old‐growth forests in northern Sweden: relations to habitat area and landscape context. Ecography 20, 425–431.


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