8 search hits
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Changes in the fledging success over time with increasing population size in the Northern Lapwing Vanellus vanellus on Wangerooge Island (Lower Saxony, Germany)
(2006)
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Julia Schröder
Mathias Heckroth
Thomas Clemens
- In this study, we report the results of a long-term investigation on changes in population size and fledging
success of Northern Lapwing on Wangerooge, a German Wadden Sea island. This population is increasing over a period
of 34 years in contrast to numerous populations in North-western Europe. The reproductive success however declines
over time and also with population density. Both effects cannot be considered separately due to autocorrelation.
However, it is noted that the population on Wangerooge is not sustained by local recruitment only. This outcome is
even more alarming as coastal areas and islands are considered as rare high quality meadow bird habitats. According
to the present results Wangerooge cannot be considered as a source habitat for Northern Lapwings in North-western
Germany.
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Breeding success of Black-tailed Godwits Limosa limosa under ‘mosaic management’, an experimental agrienvironment scheme in The Netherlands
(2006)
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Hans Schekkerman
Wolf Teunissen
Ernst Oosterveld
- Black-tailed Godwits (Limosa limosa) have been declining for decades in The Netherlands and so far this has
not been slowed by conservation measures. A new form of agri-environment scheme was tried out in 2003-2005 at 6
sites where a ‘grassland mosaic’ (200-300 ha) was created by collectives of farmers through a diverse use of fields including
postponed and staggered mowing, (early) grazing, creating ‘refuge strips’ during mowing, and active nest protection.
We measured breeding success of godwits in each of the experimental sites and nearby, paired controls. Breeding
success was higher (0.28 chicks fledged /pair) in mosaics than in controls, but due to lower agricultural nest losses only.
Chick survival was 11 % in both mosaics and controls. The amount of late-mown and other grassland suitable for chicks
hardly differed between treatments during the fledging period, mainly due to rainfall delaying postponed mowing in
all sites. Chick survival was however positively correlated with site variation in the amount of high grass (>18 cm).
Breeding success was high enough to compensate for adult mortality (ca. 0.6) in only one mosaic site. Chick survival
was lower than in previous Godwit studies, indicating that additional loss factors have increased. Predation (50-80 % of
chicks, mostly by birds) is a candidate, but changes in the suitability of late-mown grassland (insect abundance and
sward density in grass monocultures) may also play a role. Consequently a higher management investment is needed
to achieve a self-sustaining population.
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The importance of early breeding in Black-tailed Godwits (Limosa limosa)
(2006)
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Julia Schröder
Jos Hooijmeijer
Christiaan Both
Theunis Piersma
- Human impacts on the landscape have increased the penalties for Black-tailed Godwits laying their eggs
too late, especially in the very intensive agricultural landscapes of The Netherlands. Thus, godwits have experienced a
dramatic change of their fitness landscape, because the advance in mowing date made late clutches worthless destroying
either eggs or chicks. To determine the driving forces of the recent population decline we study the individual
variation in timing of breeding with respect to reproductive success in a population unaffected by mowing. Our results
show that even in a low intensity agricultural area it is very important for godwits to breed early in the season.
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Predation on meadowbirds in The Netherlands – results of a four-year study
(2006)
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Wolf Teunissen
Hans Schekkerman
Frank Willems
- Meadowbird populations in The Netherlands are under great pressure. Recently, predation is named increasingly
often as one of the key factors in contributing to the declines. A four-year research project (2001-2005) aimed to
collect (as yet mostly nonexisting) data to provide a factual basis for this discussion. A country-wide inventory based
on data for wader nests found by volunteers who mark nests for their protection from grazing/mowing indicated that
above-average predation losses are found predominantly in the half-open landscapes of northern and eastern Netherlands,
but also locally in the low-lying open grasslands which are the key areas for meadowbirds. Nest predation has
increased in recent years, but the same is true for agricultural losses, at least in areas where no nest-protection takes
place.
At a local scale, predation losses vary greatly from area to area and from year to year. Temperature loggers in nest
showed that diurnal and nocturnal predators contribute equally in total predation losses up to 50%, but higher predation
losses are mainly caused by nocturnal predators. As many as 10 animal species were identified as nest predators
on nests under surveillance with video cameras. Chick survival, investigated using radiotelemetry, was very low. About
60-80% were lost by predation, 5-15% by agricultural activities and 10-15% to all kind of other losses. At least 15
predator species were implied, with an apparently larger share taken by birds (notably Buzzard (16%) and Grey Heron
(7-18%)) than mammals, with one exception: stoat (16%). Of the most-discussed predator species, Carrion Crows were
W. Teunissen et al. Osnabrücker Naturwiss. Mitt. 32 2006
138
remarkably rarely involved in both nest and chick predation, while Red Foxes take a large toll of clutches in some areas,
but not in others.
Of all losses during the reproductive cycle about 75% and 60% was due to predation in Lapwing and Black-tailed
Godwit respectively. Predation on chicks by birds had the largest effect on total breeding success, but at the same time
elimination of this loss factor (if at all possible) alone would not be sufficient to establish a self-sustaining population.
Predation seems to have become a factor of importance in some areas, in combination with already existing other
losses. Our findings suggest that solutions to predation problems probably have to be found in locally/regionally targeted,
specific action on multiple fronts rather than countrywide measures.
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Generating and Visualizing a Soccer Knowledge Base
(2006)
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Paul Buitelaar
Thomas Eigner
Greg Gulrajani
Alexander Schutz
Melanie Siegel
Nicolas Weber
Philipp Cimiano
Günter Ladwig
Matthias Mantel
Honggang Zhu
- This demo abstract describes the SmartWeb Ontology-based Information Extraction System (SOBIE). A key feature of SOBIE is that all information is extracted and stored with respect to the SmartWeb ontology. In this way, other components of the systems, which use the same ontology, can access this information in a straightforward way. We will show how information extracted by SOBIE is visualized within its original context, thus enhancing the browsing experience of the end user.
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Ontology-based Information Extraction with SOBA
(2006)
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Paul Buitelaar
Philipp Cimiano
Stefania Racioppa
Melanie Siegel
- In this paper we describe SOBA, a sub-component of the SmartWeb multi-modal dialog system. SOBA is a component for ontologybased information extraction from soccer web pages for automatic population of a knowledge base that can be used for domainspecific question answering. SOBA realizes a tight connection between the ontology, knowledge base and the information extraction component. The originality of SOBA is in the fact that it extracts information from heterogeneous sources such as tabular structures, text and image captions in a semantically integrated way. In particular, it stores extracted information in a knowledge base, and in turn uses the knowledge base to interpret and link newly extracted information with respect to already existing entities.
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JACY - A Grammar for Annotating Syntax, Semantics and Pragmatics of Written and Spoken Japanese for NLP Application Purposes
(2006)
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Melanie Siegel
- In this text, we describe the development of a broad coverage grammar for Japanese that has
been built for and used in different application contexts. The grammar is based on work done
in the Verbmobil project (Siegel 2000) on machine translation of spoken dialogues in the
domain of travel planning. The second application for JACY was the automatic email
response task. Grammar development was described in Oepen et al. (2002a). Third, it was
applied to the task of understanding material on mobile phones available on the internet, while
embedded in the project DeepThought (Callmeier et al. 2004, Uszkoreit et al. 2004).
Currently, it is being used for treebanking and ontology extraction from dictionary definition
sentences by the Japanese company NTT (Bond et al. 2004).
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A Thousand and One Nights between Orient and Occident
(2006)
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Julia Genz
- No other country is influenced in its political, social and cultural structures by both western and eastern mentality such as Lebanon, and hardly any other country has such a pivotal function. In this mediator function it can be compared with a literary work, that merits its role in world literature as hardly any other piece of literature in regard to the co-operation of Orient and Occident. I am thinking of the collection of "A Thousand and One Nights", or with its original title "Alf Laila wa-Laila".
