Ergänzende Informationen zu Publikationen von Deborah Vogt

Bitte kontaktieren Sie Deborah Vogt um Kopien dieser Publikationen zu erhalten

2011 A database on visible diurnal spring migration of birds (Central Europe: Lake Constance) — Armbruster GFJ, Schweizer M & Vogt DR — Ecology 92: 1865

Millions of birds migrate each year between breeding grounds and overwintering areas. Migration behavior is influenced by a number of factors: day length, physiological and genetic factors, the magnetic compass, population dynamics, and weather and climatic conditions. Historical and current data on avian migration are of broad scientific value. Most of information on avian migration is presented in form of summary statistics (e.g., duration of migration, number of individuals, trend line over years) in published studies, but original data sets are not readily available. Here, we describe the first open-source archive on visible diurnal spring migration in Central Europe. The database comprises the records of a systematic field study, which covers 35541 records of migrating birds for more than 138000 specimens of 96 species. Data were collected during the spring periods of 1984, 1985, and 1986. Bird census was conducted at the tip of the Höri peninsula in Lake Constance, Germany (north of the Alps: 47°41'49.11'' N, 9°00'21.52'' E). Migrating birds were counted from the beginning of March to the beginning of May each morning using fine-grained 15-min intervals. Flock size, migration heading, and weather conditions are provided for each species, e.g., for the European Chaffinch Fringilla coelebs. In all three years we found evidence that Chaffinches ceased to migrate to northeastern and eastern direction at the end of the observation period. The migration pattern of two thrush species (Turdus merula and T. viscivorus) is also presented in more detail. Turdus merula had its migration peak always early in the morning, whereas migration of T. viscivorus was recorded from the early morning onward, with a peak at late morning to noon. Migration records are also documented for species that are generally believed to be resident birds in the inland of Central Europe (e. g., Streptopelia decaocto, Parus palustris, Certhia brachydactyla, Pica pica). Our archive might be of significance for studying patterns of daily migration, e.g., the effect of weather on spring migration intensity and for methodological studies on the same issue.

Keywords: bird migration - Bodensee (Germany) - Hori peninsula (Germany) - Lake Constance (Germany) - spring avian migration

2010 Testing spatial theories of plant coexistence: No consistent differences in intra- and interspecific interaction distances — Vogt DR, Murrell DJ & Stoll P — American Naturalist 175: 73–84 doi> 10.1086/648556

Plants stand still and interact with their immediate neighbors, and theory has shown that the distances over which these interactions occur may have important consequences for population and community dynamics. In particular, if intraspecific competition occurs over longer distances than interspecific competition (heteromyopia), coexistence can be promoted. We examined how intraspecific and interspecific competition scales with neighbor distance in a target-neighbor greenhouse competition experiment. Individuals from co-occurring forbs from calcareous grasslands were grown in isolation and with single conspecific or heterospecific neighbors at 5, 10 or 15 cm distance (Plantago lanceolata versus Plantago media and Hieracium pilosella versus Prunella grandiflora). Neighbor effects were strong and declined with distance. Interaction distances varied greatly within and between species but we found no evidence for heteromyopia. Instead neighbor identity effects were mostly explained by relative size differences between target and neighbor. We found a complex interaction between final neighbor size and identity, such that neighbor identity may only become important as the neighbor becomes very large compared to the target individual. Our results suggest that species-specific size differences between neighboring individuals determine both the strength of competitive interactions and the distance over which these occur

Keywords: competition experiment - heteromyopia - individual-based models - log response ratio - neighborhood

2005 Eine dreijährige Feldstudie zum sichtbaren Frühjahrszug am Bodensee (Süddeutschland) — Armbruster GFJ, Renz D & Schweizer M — Vogelwarte 43: 171–178
Artikel als pdf Datei herunterladen (© Deutsche Ornithologen-Gesellschaft)

We presently develop a data bank on visible diurnal spring migration. Data were collected in three spring periods (1984 - 1986) at an exposed observation point at the bank of Lake Constance (Bodensee, southern Germany). 831 observation hours were done in 194 days from beginning of March to beginning of May, each day from sunrise to late morning/midday. The project yielded 35,583 records of migrants, with a total number of 138,543 individuals in 96 species. The results from Lake Constance are briefly compared to a Dutch study (LWVT/SOVON 2002), particularly focusing on spring migration of forest birds. Moreover, the following points are addressed: median signals and phenology (with special emphasis on fourteen 'calendar' bird species and black kite Milvus migrans), migration behaviour of typical resident birds (for eurasian collared dove Streptopelia decaocto, carrion crow Corvus corone corone and house sparrow Passer domesticus), main migration heading (for penduline tit Remiz pendulinus, meadow pipit Anthus pratensis and wood lark Lullula arborea), and treecreepers Certhia brachydactyla as rare migrants. With a second, long-term investigation at Lake Constance putative changes in migration behaviour during the last decades could be detected. In the next step, we provide the final version of the database as open source, for free download from the Internet. This will allow other researchers an extension of comparative analyses, e.g. for a detailed evaluation of migration pattern and predominate weather conditions.