Magdalena Lenda

Conservation of farmland birds faces different challenges in Western and Central-Eastern Europe

Abstract. Birds are commonly used as an example of the strongly declining farmland biodiversity in Europe. The populations of many species have been shown to suffer from intensification of management, reduction of landscape heterogeneity, and habitat loss and fragmentation. These conditions particularly dominate farmland in the economically well developed countries of Western Europe. Currently, the farmland environment in Central-Eastern Europe is generally more extensive than in Western Europe and a larger proportion of people still live in rural areas; thus generating different conditions for birds living in agricultural areas. Furthermore, the quasi-subsistence farming in much of Central-Eastern Europe has resulted in agricultural landscapes that are generally more complex than those in Western Europe. To protect declining bird populations living in farmland, detailed knowledge on both species and communities is necessary. However, due to scientific tradition and availability of funding, the majority of studies have been carried out in Western Europe. In consequence this provokes a question: are findings obtained in western conditions useful to identify the fate of farmland bird biodiversity in Central-Eastern Europe? Therefore, the major goal of this paper is to highlight some local and regional differences in biodiversity patterns within EU farmland by comparing intensive agricultural landscapes with more extensive ones. More specifically, we aim to outline differences in agricultural landscapes and land use history in the two regions, use farmland birds to provide examples of the differences in species dynamics and species-habitat interactions between the two regions, and discuss possible social and ecological drivers of the differences in the context of biodiversity conservation. Factors governing spatio-temporal dynamics of farmland bird populations may differ in intensive and extensive landscapes as illustrated here using the Grey Partridge Perdix perdix and the Red-backed Shrike Lanius collurio as examples. The unevenness of farmland bird studies distribution across Europe was also presented. We call for more emphasis on pluralism in furthering both pan-European research on farmland bird ecology and conservation strategies. We also highlight some features specific to Central-Eastern Europe that merit consideration for the more efficient conservation of farmland birds and farmland biodiversity across Europe.

Plant establishment and invasions: an increase in a seed disperser combined with land abandonment causes an invasion of the non-native walnut in Europe.

Successful invasive species often are established for a long time period before increasing exponentially in abundance. This lag phase is one of the least understood phenomena of biological invasions. Plant invasions depend on three factors: a seed source, suitable habitat and a seed disperser. The non-native walnut, Juglans regia, has been planted for centuries in Central Europe but, until recently, has not spread beyond planted areas. However, in the past 20 years, we have observed a rapid increase in walnut abundance, specifically in abandoned agricultural fields. The dominant walnut disperser is the rook, Corvus frugilegus. During the past 50 years, rooks have increased in abundance and now commonly inhabit human settlements, where walnut trees are planted. Central Europe has, in the past few decades, experienced large-scale land abandonment. Walnut seeds dispersed into ploughed fields do not survive, but when cached into ploughed and then abandoned fields, they successfully establish. Rooks preferentially cache seeds in ploughed fields. Thus, land-use change combined with disperser changes can cause rapid increase of a non-native species, allowing it to become invasive. This may have cascading effects on the entire ecosystem. Thus, species that are non-native and not invasive can become invasive as habitats and dispersers change.

Railway Embankments as New Habitat for Pollinators in an Agricultural Landscape

Pollinating insect populations, essential for maintaining wild plant diversity and agricultural productivity, rely on (semi)natural habitats. An increasing human population is encroaching upon and deteriorating pollinator habitats. Thus the population persistence of pollinating insects and their associated ecosystem services may depend upon on man-made novel habitats; however, their importance for ecosystem services is barely understood. We tested if man-made infrastructure (railway embankments) in an agricultural landscape establishes novel habitats that support large populations of pollinators (bees, butterflies, hoverflies) when compared to typical habitats for these insects, i.e., semi-natural grasslands. We also identified key environmental factors affecting the species richness and abundance of pollinators on embankments. Species richness and abundance of bees and butterflies were higher for railway embankments than for grasslands. The occurrence of bare (non-vegetated) ground on embankments positively affected bee species richness and abundance, but negatively affected butterfly populations. Species richness and abundance of butterflies positively depended on species richness of native plants on embankments, whereas bee species richness was positively affected by species richness of non-native flowering plants. The density of shrubs on embankments negatively affected the number of bee species and their abundance. Bee and hoverfly species richness were positively related to wood cover in a landscape surrounding embankments. This is the first study showing that railway embankments constitute valuable habitat for the conservation of pollinators in farmland. Specific conservation strategies involving embankments should focus on preventing habitat deterioration due to encroachment of dense shrubs and maintaining grassland vegetation with patches of bare ground.

The use of metapopulation and optimal foraging theories to predict movement and foraging decisions of mobile animals in heterogeneous landscapes

Metapopulation and optimal foraging theories predict the presence of animals and their duration, respectively, in foraging patches. This paper examines use of these two theories to describe the movements and patterns of foraging in patches used by Caspian gulls (Laruscachinnans) at inland reservoirs during the chick-rearing period. We assumed that birds would move differently across diverse habitats, with some types of land cover less permeable than others, and some landscape features acting as corridors. We also expected larger and less isolated patches, and patches that were close to corridors, to have a higher probability of the presence of foraging birds, and that they would be more abundant, forage for a shorter time, and hunt smaller prey than in small, more isolated patches surrounded by barriers. Forests seem to be a much less permeable type of land cover, whereas rivers became corridors for Caspian gulls during foraging trips. Probability of bird presence was positively related to the size of foraging patches and negatively linked with distance to the nearest river, distance to the nearest foraging patch, and the presence of forests in the vicinity. The same factors significantly affected bird abundance. Contrary to expectations, the duration and success of foraging were not influenced by any variable we measured, suggesting that although larger patches contain a higher abundance of fish, their density and the probability of capturing prey were relatively stable among the various patches. However, gulls that foraged in more isolated ponds that were located further from the river and the colony, and also surrounded by forest, captured larger fish more often than birds that foraged near the colony in less-isolated patches. Pooling metapopulation and optimal foraging concepts seems to be valuable in describing patch use by foraging animals.

Different flight behaviour of the endangered scarce large blue butterfly Phengaris teleius (Lepidoptera: Lycaenidae) within and outside its habitat patches

Understanding individual movements in heterogeneous environments is central to predicting how landscape changes affect animal populations. An important but poorly understood phenomenon is behavioural response to habitat boundaries and the way animals cross inhospitable matrix surrounding habitat patches. Here, we analyze movement decisions, flight behaviour, and activity of the endangered scarce large blue Phengaris (Maculinea) teleius, focusing on the differences among the patterns observed in patch interior, at patch boundaries and within matrix. The probability of crossing an external patch boundary, regardless of the land use in the adjacent area, was considerably lower than crossing a ‘control line’ within patch interior. Movement distances, flight durations and net squared displacement were largest in matrix, while similarly smaller at patch boundaries and in patch interior. The distribution of angles between successive movements was clearly clustered around 0° (indicating flight in a straight line) in matrix and at patch boundaries, but not in patch interior. There were no differences in time spent on foraging, resting and ovipositing between patch interior and boundaries, but the first two activities rarely, and oviposition never, happened in matrix. Our results suggest that although P. teleius adults do not avoid using the resources located in the boundaries of habitat patches, they often return to the interior of the patches when crossing their boundaries. However, having entered the matrix the butterflies perform relatively long and straight flights. The estimated probability of emigration and net squared distance implies that the dispersal between local populations is common in this species in the studied area.

Butterfly responses to environmental factors in fragmented calcareous grasslands

Although there is much research showing a strong negative effect of habitat fragmentation and deterioration on the viability of different insect populations and on species richness, the effect of fragmentation is modified by other local and landscape factors. One of the most substantial gaps in knowledge is whether species are similar in their response to the same environmental factors and if their response mirrors response of the entire community. From the conservation point of view this knowledge is of primary importance in planning conservation actions, yet these studies are rare. In this paper we test the relative effects of habitat patch and landscape characteristics on butterflies inhabiting calcareous grasslands in southern Poland. Butterfly species richness and abundance were positively affected by patch size and wind shelter. In the case of species richness there was also a positive effect of plant species richness. Butterfly diversity was enhanced in wind sheltered patches, and commonness (non-rarity) enhanced by distance to buildings and by shorter vegetation. Multivariate analysis suggested differences in the responses of individual species to the examined environmental variables, with some species more responsive to patch size and shelter and others to sward height. The conservation of butterfly communities requires sensible and complex management to ensure high habitat diversity. The most important challenge for future studies on calcareous grasslands is to formulate a model of management that guarantees high species richness and conservation of each individual species.

Corridors, local food resources, and climatic conditions affect the utilization of the urban environment by the Black-headed Gull Larus ridibundus in winter.

Black-headed Gulls Larus ridibundus (BHGs) in urban areas are a public nuisance. The aim of this study is to investigate the factors affecting the occurrence and abundance of the BHG foraging in urban areas in winter. The study was conducted in the city of Krakow (southern Poland) in four easily identifiable urban habitats: (1) areas with blocks of flats, (2) areas with congested housing, (3) detached single-family housing and (4) green areas. In each of these four habitats, 60 small (1-ha) plots were randomly chosen, and the bird’s presence and abundance were noted. Results revealed that birds occurred most frequently and in the largest numbers in plots with blocks of flats and green areas as well as plots located close to rivers and water reservoirs. This highlights the importance of ecological corridors and stepping-stones for the presence of this species in the city. Food resources had no effect on the presence of the gulls but the abundance of the species was positively correlated with the number of litter-bins. This indicates that local food resources could be more important than large landfills for this species in urban habitats during winter. No human disturbance indices had an effect on the occurrence and abundance of the BHG. Higher temperature and lack of snow cover positively affected utilization of the urban habitats by the species that indicates that global warming may speed up synurbanization of the BHG. To control the number of BHGs in urban areas, we suggest preventing access to local food resources by placing litter bins with waste baskets that are inaccessible to animals. Also, the public should behave appropriately towards gulls and refrain from feeding them intentionally.

Effect of the Internet Commerce on Dispersal Modes of Invasive Alien Species

The spread of invasive alien plants has considerable environmental and economic consequences, and is one of the most challenging ecological problems. The spread of invasive alien plant species depends largely on long-distance dispersal, which is typically linked with human activity. The increasing domination of the internet will have impacts upon almost all components of our lives, including potential consequences for the spread of invasive species. To determine whether the rise of Internet commerce has any consequences for the spread of invasive alien plant species, we studied the sale of thirteen of some of the most harmful Europe invasive alien plant species sold as decorative plants from twenty-eight large, well known gardening shops in Poland that sold both via the Internet and through traditional customer sales. We also analyzed temporal changes in the number of invasive plants sold in the largest Polish internet auction portal. When sold through the Internet invasive alien plant species were transported considerably longer distances than for traditional sales. For internet sales, seeds of invasive alien plant species were transported further than were live plants saplings; this was not the case for traditional sales. Also, with e-commerce the shape of distance distribution were flattened with low skewness comparing with traditional sale where the distributions were peaked and right-skewed. Thus, e-commerce created novel modes of long-distance dispersal, while traditional sale resembled more natural dispersal modes. Moreover, analysis of sale in the biggest Polish internet auction portal showed that the number of alien specimens sold via the internet has increased markedly over recent years. Therefore internet commerce is likely to increase the rate at which ecological communities become homogenized and increase spread of invasive species by increasing the rate of long distance dispersal.

Short-Lived Ants Take Greater Risks during Food Collection

Life-history theory predicts that organisms should alter their behavior if life expectancy declines. Recent theoretical work has focused on worker life expectancy as an ultimate factor in allocating risk-related tasks among the workforce in social insects. A key prediction of this evolutionary model is that workers with shorter life expectancy should perform riskier tasks. We tested this hypothesis, using laboratory colonies of the ant Myrmica scabrinodis. We modified foraging so that it differed in level of risk by manipulating distances, temperatures, and the presence of competitors on foraging patches. The life expectancies of foragers were shortened by poisoning with carbon dioxide or by injury through removal of their propodeal spines. Both treatments significantly shortened worker life expectancy in comparison with untreated ants. We show, for the first time, that foragers with a shorter life expectancy foraged under risk more often than foragers in the control group. Thus, a worker’s strategy of foraging under risky circumstances appears to be fine-tuned to its life expectancy.

New methods of crop production and farmland birds: effects of plastic mulches on species richness and abundance

Summary 1. Modern methods of crop production are regarded as one of the major factors moderating ecosystem processes in agricultural landscapes and may negatively affect farmland biodiversity. One method which is on the increase is mulching: the use of plastic foil to cover crops at sowing in order to promote early growth by reducing the negative effects of variable temperatures and to limit pesticide use. However, almost nothing is known of the role of mulching on farmland biodiversity. 2. In this study, carried out in southern Poland in 2011, we investigated the impact of mulching with plastic foil on the number of species and abundance of farmland birds at two spatial scales. 3. At the local scale, bird species number and abundance were lower in areas where foil was used than those in the control areas, both during the period when the foil was used and after it was removed from the crops. At the landscape scale, we found a significant negative relationship between the proportion of crops covered by foil and bird species richness and abundance. Farmland specialists, nonfarmland birds, ground nesters and above-ground nesting species were all negatively affected by foil mulching. Foil had a negative effect on potential resources for birds including adult butterflies and their larvae and weed species. 4. Synthesis and applications. Our results provide the first evidence that the use of foil for mulching has negative effects on farmland bird populations, probably through the trophic cascade and habitat disturbance. Therefore, foil mulches must be considered as another factor contributing to the decline of farmland biodiversity. We suggest limiting the use of this method of vegetable production at the farm level. Decreasing the field size and converting some arable fields into grassland patches are proposed as mitigation measures in landscapes with high foil cover.