Ambrosia artemisiifolia is the most noxious invasive species of weed in Hungary. The aim of this study was to quantify the environmental and land-use factors that explain the variance in its abundance in arable fields. A survey of 243 arable fields was carried out across Hungary, and 19 environmental and 12 land-use factors were measured. These were used as explanatory variables in classification and regression tree models. The abundance of A. artemisiifolia was significantly higher at the edges than at the centres of fields. The most important land-use variables explaining the variance in abundance of A. artemisiifolia were crop type and crop cover, with the highest abundance recorded in sunflower fields and fields with low crop cover. The following explanatory environmental variables were associated with significantly higher A. artemisiifolia abundance: sandy or acidic soils, mean April precipitation > 39 mm, mean annual precipitation > 592 mm and mean May temperature < 15.5 °C. Ambrosia artemisiifolia was significantly less abundant in fields with soils containing high concentrations of Na, K and Mn. Both farmers and nature conservationists should be made aware of the conditions and practices that favour ragweed so that they can develop effective and selective ragweed control practices, particularly in arable habitats with a high diversity of weeds.
The number of little owls, Athene noctua is decreasing in many European countries. In order to evaluate causes of the decline in Poland, habitat preferences of this species were analysed. Using GIS methods, 25 settled territories of the little owl, recorded during field surveys between 2000 and 2005, were compared with 50 unsettled locations. It was found that the proportion of built-up areas was higher in the occupied territories than in the random locations. No differences in grassland, forest and field proportion, habitat diversity and edge length were recorded between the occupied, and the random locations. The amount of forest and the proportion of built up areas appeared to be the best predictor of the occurrence of the little owl. Next, habitat use at 7 additional territories, which were occupied by little owls in 1980–90s and later abandoned, was analysed. In 2006, as compared to the period 1980–90, numbers of pollard willows decreased, whereas the number of buildings increased in these territories. The overall results lead to a conclusion that the little owl shows a high degree of habitat plasticity. The decrease of the area of grasslands and numbers of pollard willows is not likely to explain the population decline of the species.
Studie shrnuje výsledky studia vztahů mezi klimatickými změnami a osídlením a využíváním krajiny v době poledové. Výzkum ukázal, že proměny klimatu se na pravěkém zemědělství a využívání krajiny odrážely zásadním způsobem a že ovlivnily vývoj pravěkých kultur. Optimalizovaný systém využívání krajiny, vytvořený jednou pravěkou kulturou, se stal při klimatických změnách fragilní. Reakcí na klimatické fluktuace, spočívající v nutnosti změny strategie využívání krajiny, byl někdy i zánik jedné archeologické kultury a její nahrazení kulturou novou. and The article summarizes the results of the study of relations between the prehistoric settlement pattern and climate during the Holocene. The pattern of relations between prehistoric settlement and landscape reflected climatic fluctuations. All prehistoric cultures had to find the optimal strategy of land use under given conditions, and the optimalized system of agriculture/animal husbandry became fragile; climatic changes caused usually the end of one prehistoric culture, while the next culture often reflected the necessary changes of economic strategy; establishment of a new system developed as a response to the new situation.
Factors which have a negative impact on mammal populations were reviewed for all 83 native species occurring in Germany today. Forest management affects most species of the mammal fauna as well as of the sub-groups of Red List species and of species for which a special responsibility for their conservation has been determined in Germany. This is because a high proportion of German mammals are forest-dwelling, which means they are exposed to current harmful forestry practices such as selective harvest of ancient trees. The review also highlights population reduction by direct take of individuals (legal, illegal or accidental) and habitat fragmentation as major conservation problems affecting many species. The analysis of negative impact factors underline the importance of ongoing „traditional“ conservation measures. However, the result of climate change and invasive alien species being less important for conservation, as only few species are affected so far in Germany, is doubtful. The impacts of these two factors may be underestimated owing to a general lack of data. To ensure that conservation problems can be identified and appropriate measures are taken, the implementation of a mammal monitoring programme and specific research projects are needed. International cooperation might be helpful to overcome national shortcomings in mammal conservation in Germany and other European countries.
The abandonment of less productive agricultural land and the intensification of agricultural land use are the main features of the Common Agricultural Policy (CAP) that Croatia will enforce now as new member of the EU. Due to
demographic changes and the economic transition in Croatia resulting from
war in the 1990s, substantial tracts of agricultural land were abandoned. We investigated two habitat types in the protected floodplain landscape of Lonjsko polje in the continental part of the country: arable land and pastures.
Both habitats were maintained by agricultural management and suffered from partial abandonment. Land abandonment increased the susceptibility to encroachment by the invasive plant species Amorpha fruticosa. Data on bird communities were obtained during the breeding season in 2010 while there were high water levels in the floodplain. Data were collected from 63 points, and a total of 1447 individuals from 70 species were recorded during
the study. We found that the bird community structure was primarily related to the presence/abandonment of agricultural land use and the habitat type. Further, we detected that the bird community structure in the same habitat type differed by management intensity. Open habitat specialists were most influenced by land abandonment. However, the conservation value (according to the Species of European Conservation Concern value, SPEC) of grazed pastures and abandoned pastures did not differ significantly, in part because the overgrown pastures with high water levels were found to be suitable for Acrocephalus species. The shift in bird community structure between abandoned and managed arable lands were smaller than those
detected in the pastoral communities. Because land abandonment is a widespread phenomenon in Croatia, we emphasize the urgent need
for a nationwide monitoring program for farmland birds to register the resulting changes in farmland bird communities and to develop appropriate agri-environment measures to mitigate the process.