This study compares biodiversity indicators based on plant and bird communities in eight mosaic landscapes in Hungary, dominated by a mixture of agro-ecosystems and grasslands. The eight landscapes were selected to represent the diversity of the mixed agricultural landscapes of South-East Europe, where a mosaic pattern of intensively managed farmlands and high nature value semi natural grasslands is still relatively prevalent. Bird communities were described using several assemblage-level (species number, total abundance, and Shannon diversity of the assemblage, based on 15 pre-selected key farmland bird species), as well as species-level (presence/absence of the 15 bird species) indicators, which were checked against a synthetic landscape quality indicator describing the degradation of the local plant communities with respect to an ideal baseline (vegetation-based natural capital index, NCI). The authors were interested if and how the assemblage- and species-level bird indicators can describe landscape quality in South-East European agricultural mosaic landscapes.
It was found that assemblage-level bird indicators were poorly associated to the landscape quality measured in terms of NCI: only total abundance correlated significantly with NCI. On the other hand, species-level indicators were much more successful in predicting landscape quality. Six (Alauda arvensis, Emberiza calandra, Falco tinnunculus, Motacilla flava, Limosa limosa, Vanellus vanellus) of the 15 farmland bird species studied showed significant positive correlation with NCI, while three species (Emberiza citrinella, Galerida cristata, Sylvia communis) exhibited negative correlations. We also found that it was possible to draw conclusions about the landscape quality in an agricultural landscape based on the bird communities better, than to predict the bird assemblages from vegetation condition.
The negative correlations for species that indicate good quality habitats in Western Europe, underline the context specificity of biodiversity indicators: whereas the conditions preferred by these species can be considered relatively natural in Western Europe, they correspond to relatively degraded habitats in South-East Europe. The nine farmland bird species which showed a significant connection to NCI can be seen as potential candidates for a regional Farmland Bird Index customized for agricultural landscapes in South-East Europe, in the Pannonian biogeographic region, or in Hungary