Martin Wikelski
New data on the migration of European animals
[pp. 11-28, 11 coloured and 2 black-and-white figures, 1 table]

The use of miniature transmitter gave a boost to the study of animal migrations. Up to now, the databank movebank holds over 500 millions GPS points worldwide. These data sets now allow us to study population processes by using the patterns of movement of individual animals. Within blackbird populations with different migration behavior, the survival probability of migratory birds exceeds that of sessile ones. Furthermore, the individual tracking of storks gives details about the use of energy during their flight and at the ground, but also about the causes of death along their migration routes. Population analyses can then help to recognize the main risks along the migration routes, and thus contribute to the development of sustainable and adequate conservation strategies. At the moment, nearly all of the GPS tagged juvenile storks die along the eastern migration route to Africa. Finally, the data of tagged sea gulls and doves help to study navigation and orientation of birds.

Within the nascent ICARUS project, a global transmitter system to study natural events and life processes on earth will be established, which also includes migration movements of animals. While the sampled data of conventional miniature transmitters must be downloaded from the data logger, the new transmitters used in the ICARUS project will send movement data or, e. g., meteorological data worldwide continuously and in near-real time to the movebank databank. Thus, tagged animals will help to forecast natural disasters, to recognize the spread diseases via animals or to observe weather conditions.

Ilse Storch
Changes in the wildlife fauna of Central Europe: What are the differences between “winners” and “losers”?
[pp. 29-42, 8 coloured and 2 black-and-white figures]

The article summarizes how the wildlife fauna of Central Europe has changed in recent decades. While some species have increased to the extent that they are already perceived as problematic (“problem animal beaver”), others make it into the headlines through seemingly bizarre conservation decisions (“hamster stops highway construction”). The successful comeback of the “winners” – species that increase in distribution and abundance – and the poor status of the “losers” – threatened species with negative population trends – are related to human land use and attitudes.

Based on case studies, the paper discusses these issues for larger mammalian species occurring in Germany. Common, adaptable species favoured by land use and climate warming are the wild boar, roe deer and red fox; species formerly extirpated by intensive hunting, but now re-expanding are the wolf and the beaver; and relative newcomers (Neozoans) include the raccoon and the racoon dog. In contrast, some species with specialized habitat needs, such as the European hamster and European hare, continue to decline due to intensified human land use, especially of the open landscape.

Wolfgang Fiedler
Changes in migration and breeding behaviour of birds
[pp. 43-56, 2 colour plates, 5 coloured and 2 black-and-white figures, 1 table]

To a certain extent, birds can react to changes in climate with changes in migration and breeding behaviour. Warmer springs in recent years have led to an advance of the spring migration in most migratory bird species, while the autumn migration shows a more complex pattern. The onset of breeding (date of egg laying) has also advanced in many species, resulting in a prolonged breeding period, which may even permit a second clutch. Other predicted effects of warmer climate, such as an increase in clutch size due to earlier egg laying, are prominent in some species, but barely detectable in others. Details of migration behaviour, such as the time difference in male and female arrival, are also changing in some species. Many species now shorten their migration routes to winter closer to their breeding grounds, and in populations of partial migrants, the share of nonmigrants is increasing.

The paper focuses on three aspects: (1) Not all environmental changes that cause behavioural changes are due to climate change. Human activity directly affects birds’ environment, but also indirectly, for example, via changes in agricultural practices. (2) It is often unclear which of the observed changes are phenotypic and which involve genetic changes. In other words, to what extent can individual behavioural plasticity balance environmental changes and where do we see evolutionary adaptations shaped by mutation and selection. And, finally, (3) are there limitations of evolutionary adaption.

Franz Bairlein
Changes in populations of middle European birds
[pp. 57-72, 9 coloured and 1 black-and-white figures, 1 table]

Bird populations in Central Europe over the last decades have developed dichotomously. Some, such as the white stork, common crane, white-tailed eagle, and the Eurasian blackcap, for which conservation programs have been successful, are increasing. The populations of many other species, especially those of agricultural landscapes, such as the peewit, Eurasian skylark and common starling, however, have decreased. This is also the case for species migrating to tropical wintering grounds, like the cuckoo and the redstart.

In most of these cases, we know little or nothing about the underlying causes, which especially for migrating species are manifold and complex. These species are affected by conditions in the breeding area, along their migrating routes, and in their wintering area, including ecological and climatic factors as well as human predation. Causal analyses are necessary to detect and document the full range of these factors; “intuitive” associations or explanations are mostly inadequate. Only if we understand changes in populations (decreases as well as increases) causally, will we be able to develop sustainable conservation strategies and instruments. The best approach are comparative analyses, for example, using species that are ecologically similar but differ in their migration patterns, or that show regionally different population trends. The common starling, for example, has increasing population densities in the south of Germany, but decreasing ones in the north. Reasons for this are currently unknown.

Josef H. Reichholf
Butterflies and birds: Why did their abundance change within the last centuries?
[pp. 73-90, 4 coloured and 10 black-and-white figures]

Over the past 50 years, the populations of many animal species have decreased markedly, with farmland species being most severely hit. However, there have also been spectacular comebacks, such as those of the Grey Crane, the White-tailed Eagle, the Osprey, and others. To explain such changes in abundances, it has become convenient to blame climate change. For birds and Lepidoptera (butterflies and moths), however, recent changes in climate appear to have had a small impact if any. Instead, decreased abundances were caused by highly industrialized farming practices with oversized fields stocked with monocultures, especially maize (corn), a fertilizer oversupply, and extensive use of herbicides and pesticides. In towns and forests, abundances of butterflies and moths have not significantly changed, although populations of Lepidoptera whose caterpillars feed on the nitrogen-tolerant stinging nettles have increased. In agricultural landscapes, by contrast, the abundances of most Lepidoptera have decreased by >80 % since the early 1970s. This downward trend is closely mirrored by the farmland bird species in the study area (in Bavaria) as well as in the European Union in general. In forests or cities, however, most bird species have maintained their population sizes. The growing populations of some of the “comeback” bird species are due to their protection from shooting. Intensive hunting likewise has destroyed the former attempts of European Bee-eaters to breed in Bavaria. The species now breeds successfully due to legal protection, and its recent increase, therefore, is a result of this protection and not primarily caused by climatic warming. Anthropogenic climate change as a facile explanation for faunal changes currently may hinder the search for more direct underlying causes.

Axel Hausmann
The project Barcoding Fauna Bavarica: monitoring of population changes and range extensions of insects in Bavaria
[pp.  91-104, 9 coloured figures, 1 table]

The insect fauna of the state of Bavaria comprises some 30 000 species (about 80 % of Bavaria’s fauna). Insects live in all types of habitats and ecological niches. A high percentage of the species have narrow niche requirements, making them good indicators of environmental change. Monitoring of insects, however, is hampered by difficult species identification, a lack of taxonomists, and immensely time-consuming workflows, especially considering the huge numbers of individuals and species from bulk samples. Insect monitoring has therefore been largely restricted to butterflies, grasshoppers, and dragonflies. These easily identifiable groups, however, make up just 1 % of the Bavarian insect fauna. The problem can be overcome by DNA barcoding, i. e., by species identification through a sequence in the mitochondrial COI 5’ gene. As part of the “Barcoding Fauna Bavarica” project, which began in 2009, the Bavarian State Collections of Zoology have produced DNA barcodes for 20 000 species, all deposited and accessible in an international online database. Up to now, six new lepidopteran (moth) species for Central Europe, 26 new species for Germany, and 60 new species for Bavaria, and even higher numbers of hymenopteran and fly species have been discovered. The recently developed method of Next-Generation Sequencing (NGS) allows the identification of numerous species from a single sample. The efficiency and reliability of NGS analyses was demonstrated in a pilot project (early warning system for invasive and pest-relevant species; project “German Barcode of Life”).

Sylvia Cremer
Invasive ants in Europe: how they spread and change the native fauna
[pp. 105-115, 10 coloured figures]

The social insects bees, wasps, ants, and termites are species-rich, occur in many habitats, and often constitute a large part of the biomass. Many are also invasive, including species of termites, the red imported fire ant, and the Argentine ant.

While invasive social insects have been a problem in Southern Europe for some time, Central Europa was free of invasive ant species until recently because most ants are adapted to warmer climates. Only in the 1990s, did Lasius neglectus, a close relative of the common black garden ant, arrive in Germany. First described in 1990 based on individuals collected in Budapest, the species has since been detected for example in France, Germany, Spain, England, and Kyrgyzstan. The species is spread with soil during construction work or plantings, and L. neglectus therefore is often found in parks and botanical gardens. Another invasive ant now spreading in southern Germany is Formica fuscocinerea, which occurs along rivers, including in the sandy floodplains of the river Isar. As is typical of pioneer species, F. fuscocinerea quickly becomes extremely abundant and therefore causes problems for example on playgrounds in Munich.

All invasive ant species are characterized by cooperation across nests, leading to strongly interconnected, very large super-colonies. The resulting dominance results in the extinction of native ant species as well as other arthropod species and thus in the reduction of biodiversity.

Annette Menzel
Climate change and its influence on animals and plants
[pp. 117-132, 12 coloured figures]

The ongoing rapid climate change has already led to strong changes in the global flora and fauna. For a formal attribution of observed changes to human-induced climate change (as attempted in the Intergovernmental Panel on Climate Change IPCC), however, one needs scientific methods of detection and attribution. These involve (1) selection of suitable parameters, the changes in which can be directly linked to the anthropogenic influence via greenhouse gas emissions, such as warming of atmosphere and oceans, sea level rise, and decline of snow and ice cover in the Arctic. (2) Detection of significant changes in flora or fauna based on long-term observational time series related to one of the climate-related parameters, non-climatic drivers of floristic or faunistic change, such as land use and land degradation, must be largely excluded. Examples for such climate-attributable change include earlier leaf-out, earlier flowering, or earlier fruiting. (3) Lastly, analyses of spatial-temporal patterns and the statistical correlation between changes in the climate parameters and the observed floristic, faunistic, or phenological changes.

Not all changes should automatically be attributed to climate change. Thus, changes in the timing and abundance of pollen production, as an example, also reflect changes in land use and land cover, eutrophication, and newly invasive plant species.