Montag, 19 Dezember 2022 15:58

JIGUET, F., DOXA, A. & ROBERT, A. (2008)

The origin of out-of-range pelicans in Europe: wild bird dispersal or zoo escapes?

Ibis 150(3), Juli 2008:606–618, doi:10.1111/j.1474-919X.2008.00830.x

Abstract:

We tested whether spatial and annual patterns of occurrence of out-of-range Great White Pelecanus onocrotalus, Dalmatian Pelecanus crispus and Pink-backed Pelicans Pelecanus rufescens recorded in Europe between 1980 and 2004 supported a natural vagrancy theory. Candidate variables tested were those likely to influence dispersal and escape probability (distance to the usual breeding/wintering range, national captive stock), and wild breeding population sizes and their movements (size of breeding colonies, climate conditions on wintering grounds or during dispersal). Spatial vagrancy patterns supported the hypothesis of wild birds dispersing from their normal range, with decreasing national totals with increasing distance to the usual range for the three species. Annual out-of-range numbers of Great White Pelican were predicted by breeding colony size and breeding success in Greece, with a further effect of Sahel rainfall during the previous year. Annual numbers of Dalmatian Pelican were related to the North Atlantic Oscillation index and to breeding success in Greece. Finally, annual numbers of Pink-backed Pelican were predicted by summer Sahel rainfall, which is known to drive dispersal of the species northwards into the sub-Sahelian steppes during wet summers there. Hence, annual vagrancy patterns in Europe were well predicted for all three species by population size indices, reproductive success and/or climatic components, which presumably influence survival and/or dispersal. We therefore consider that vagrancy patterns were driven by wild birds, whereas escapes – even if potentially numerous – do not create sufficient ‘noise’ to hide these patterns.

jiguet-biblio

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Donnerstag, 06 August 2020 13:14

CSAR, D., SCHAUER, M. & GUMPINGER, C. (2012)

Long-term investigation on fish migration patterns between pre-alpine lakes and their major tributaries with special focus on protected species within SAC areas.

Conference Paper 9th ISE 2012, Vienna. (PDF)

Abstract:

In the designated SAC (Special Area of Conservation) site“Mond-und Attersee” (comprising two large pre-alpine lakes in Upper Austria and the mouths of their major tributaries) the spawning migration of the protected species pearlfish (Rutilus meidingeri) and Danube bleak (Alburnus mento) was investigated in the years 2004 and 2010. For this purpose, a dynamic fishweir with an integrated trap for catching upstream migrating fish was installed near the mouths of the respective rivers. The main factor correlating with the spawning migration turned out to be the water temperature of the rivers. Furthermore, differences between sexes were found concerning body length and weight as well as the main immigration period into the streams.

csar-biblio

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Freitag, 24 Februar 2017 15:43

RICHTER, H. V. & CUMMING, G. S. (2006)

Food availability and annual migration of the straw-colored fruit bat (Eidolon helvum).

Journal of Zoology 268: 35–44.
doi:10.1111/j.1469-7998.2005.00020.x

Abstract:

Animal migrations offer a unique opportunity for developing and testing hypotheses about the ecological requirements of different species and the tradeoffs that they make between conflicting life-history demands. There has been relatively little research into the causes and consequences of migrations by fruit bats, despite their potential significance for pollination and seed dispersal. We assessed the causes of one of the most spectacular migrations of fruit bats known: the annual influx of an estimated 5–10 million E. helvum into Kasanka National Park in Zambia. We tested several predictions based on the hypothesis that E. helvum migrates to exploit seasonal variations in food supply opportunistically. Phenological data, feeding observations and monitoring of fruit bat movements provided the first quantitative evidence in support of the hypothesis that the migration of E. helvum in Zambia is driven by food supply. The E. helvum colony exhibited several surprising behaviors, including a tendency for migratory satellite colonies to aggregate, rather than to disperse, during the time of peak food production, and a tendency to fly well beyond the most immediate food sources when foraging. Alternative hypotheses to explain the E. helvum migration were not supported, but further research is needed to clarify the results of this preliminary study. Both the size of the colony and its potential for large-scale movements suggest that this bat may play an important economic and ecological role over a significant portion of sub-Saharan Africa. Information is still lacking about migration routes, food sources, habitat requirements and the role of migration in disease transmission between colonies of E. helvum.

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Donnerstag, 14 Juni 2018 16:08

REMPFLER, T. (2013)

Raum-Zeit-System des Rothirsches im Wildnispark Zürich und dessen Umgebung.

Masterarbeit

55 Seiten

Institut Umwelt und Natürliche Ressourcen der ZHAW, Wädenswil
Betreuung: Prof. Dr. sc. ETH R.E. Graf, Dozent Forschungsgruppe Wildtiermanagement WILMA
in Zusammenarbept mit Wildnispark Zürich / Wildpark Langenberg (Direktor: Ch. Stauffer)

Volltext

Zusammenfassung:

Der Rothirsch Cervus elaphus  L. war im 19. Jahrhundert in der Schweiz weitgehend ausgerottet. Ausgehend von den Alpen und Voralpen breitet er sich heute aus und besiedelt auch das Mitteland wieder. Im Wildnispark Zürich (WPZ) ist er seit ca. 20 Jahren vermehrt anzutreffen. Ziel dieser Studie war es, die Verbteitung des Rothirsches im WPZ und dessen Umgebung zeitlich und räumlich zu beschreiben. Weiter waren Bestandesgrösse, Bestandeszusammensetzung und Wanderrouten aufzuführen.

Das Untersuchungsgebiet umgab den WPZ grossräumig und erstreckte sich von der Stadt Zürich im Osten bis nach Lachen (Kanton Schwyz), und im Süden bis zum Rossberg. Die Datenerhebung erfolgte im gesamten Perimeter über Befragungen von Fachkundigen zu Hirschnachweisen, im Sihlwald zusätzlich über ein Fotofallenmonitoring. Als Nachweise galten jagdliche Abschüsse, Fallwild, eindeutig zuordnungsbare Fegestellen, Losung, Schälschäden, Suhlen, Trittsiegel, Sichtbeobachtungen und Fotos. Das Monitoring generierte mit 19 Fotofallen Daten von Ende November 2012 bis Mitte Mai 2013. Die Kantonalen Jagd- und Fallwildstatistiken aus den Jahren 1999 bis 2012 ergänzten die Datenaufnahme. Ein übernommenes GIS-gestütztes Habitatmodell, das auf Expertenmeinungen beruhte, stellte die erhobenen Informationen in einen räumlichen Bezug.

Im Fotofallenmonitoring waren ein Achtender und zwei Spiesser eindeutig zu identifizieren. Unter Berücksichtigung der Nicht-Identifizierbarkeit weiblicher Individuen und Jungtiere sowie teilweise unzureichender Bildqualität, schätzte ich den Bestand aufgrund der Fotos auf fünf bis zwölf Individuen.

Aus den Befragungen sowie den Jagd- und Fallwildstatistiken ging hervor, dass die Hirschnachweise nach einem Zwischenhoch in den 1980er Jahren wieder abnahmen und erst seit dem Jahr 2010 anhaltend zunehmen. Als Hauptverbreitungsgebiete stellten sich der Kanton Schwyz, der Höhronen, der Morgartenberg, die Gebiete südwestlich des Aegerisees inkl. Hürital, der Zugerberg, die Baarburg und die Albiskette, insbesondere der Sihlwald heraus.

Alle diese Gebiete bewertete das Habitatmodell mit für den Hirsch geeigneten Bedingungen. Folglich liegt die Erwartung nahe, dass auch weitere, gemäss Modell günstige Lebensräume vom Rothirsch besiedelt werden. Diese muss aber nicht zwingend erfüllt werden, da das Modell zwar die Landschaft bewertet, aber z.B. unterbrochene Ausbreitungsachsen nicht berücksichtigt. Hingegen konnten die Befragten intakte Wanderrouten grob bezeichnen und dabei im Wesentlichen die Hauptverbreitungsgebiete untereinander verbinden. Der Rothirsch kommt im Sihlwald ganzjährig vor, wobei die spärlichen Fotofallennachweise in den Monaten Januar, Februar, April und Mai dafür sprechen, dass der Lebensraum der Hirsche zumindest in diesen Monaten über den Sihlwald hinausreicht.

Die Fotofallen lieferten an 11 der 19 Standorte insgesamt 31 Rothirschnachweise. Aufgrund der Empfindlichkeit des Hirschs gegenüber menschlichen Störungen war zu erwarten, dass im Verhältnis zur Anzahl Fallen innerhalb der Kernzone, in der menschliche Aktivitäten durch Besucherlenkungsmassnahmen reguliert sind, mehr Hirschnachweise gelingen würden als ausserhalb. Das Fotofallenmonitoring hat dies tendenziell bestätigt. Weiter lieferte es ausschliesslich Nachweise zwischen 14:00 Uhr und 06:00 Uhr (Europäische Winterzeit), was auf eine recht ausgeprägte Nachtaktivität hindeutet. Auch dieses Verhalten kann als Anpassung an die menschlichen Aktivitäten interpretiert werden.

Für detailliertere Erkenntnisse zum Raum-Zeit-System des Rothirsches im Wildnispark Zürich sind zusätzliche Untersuchungen nötig. Zum einen dürfte das Fortführen des Fotofallenmonitorings während eines weiteren Jahres einen vertieften Einblick in saisonale Unterschiede ermöglichen. Telemetriestudien sind darüber hinaus geeignet, das Verhalten von Wildtieren auf einer feineren Skala zu beschreiben. Weiter werden daraus exakte Wanderrouten sichtbar.

Genetische Methoden werden zur Bestandesschätzung (Minisatelliten), aber auch zur Identifizierung von Populationen eingesetzt (Microsatelliten und mitochondriale DNA), woraus zu schliessen wäre, mit welchen anderen Populationen die Hirsche im Sihlwald in Verbindung stehen oder standen, und wo sie ursprünglich herkamen.

Abstract:

Red deer Cervus elaphus  L. were largely extinct in Switzerland by the 19th century. However, the species has been dispersing from the Alps and Alpine foothills in recent times and is currently recolonising the Swiss Midlands. In the Wildnispark Zürich (WPZ), their numbers have been increasing for approximately 20 years. The aim of this study was to describe the temporal and spatial distribution of red deer in the WPZ and its surroundings. In addition, population size, the composition of the population and dispersal routes were investigated.

Though centred around WPZ, the study area extended from Zurich in the west to Lachen in the east (canton Schwyz), and to the Rossberg in the south. Interviews were conducted with experts regarding evidence of deer presence over the whole study area. Shot animals, damage on trees caused by antlers, scats, peeled bark, wallows, tracks, direct observations and photographs were regarded as evidence of presence. In addition I conducted a monitoring program using camera traps in the Sihlwald. Nineteen camera traps provided data from the end of November 2012 until mid May 2013. Cantonal hunting statistics from 1999 to 2012 completed the dataset. An existing habitat model in GIS based on expert opinion enabled extrapolation of spatial information.

The camera traps took pictures of one eightpointer and two male yearlings. Considering that females and calves could not be individually identified, and some images were of insufficient quality, I estimated an absolute abundance of five to twelve individuals.

Interviews and hunting statistics showed a peak in deer presence in the 1980’s. After a decrease in numbers, they have increased continuously since 2010. The main areas of distribution are Canton Schwyz, Höhronen, Morgartenberg, south-western area of Aegerisee including Hürital, Zugerberg, Baarburg and Albis range, particularly the Sihlwald. The habitat model showed suitable conditions for red deer in all these areas. Therefore, it would be expected that other suitable areas indicated by the model will also be colonised by red deer. However, this may not necessarily be the case since the model judges landscapes but does not take into account interrupted dispersal corridors, for example. By contrast, respondents were able to roughly describe intact migration routes and to connect the main areas of distribution.

In the Sihlwald, red deer show a year-round presence. The fact that only few photos were taken by the camera traps in January, February, April and May indicates that homeranges of deer extend beyond the Sihlwald at least during these months. Camera trapping provided 31 photos of red deer in 11 out of 19 locations. Red deer react sensitively to human disturbance. Therefore, it was expected that - in proportion to the number of traps - traps inside the core area would provide more photos of the animals than cameras outside, because human activities are regulated inside this area. Camera trapping has confirmed this trend. Furthermore, photos of red deer were taken exclusively between 02:00 p.m. and 06:00 a.m. (European wintertime), which indicates a typically nocturnal lifestyle.

This behaviour can also be interpreted as an adaptation to human activities. Additional studies are necessary to obtain a more detailed insight into spatial and temporal patterns of red deer activity in the WPZ. Continuing camera trapping for another year might give a better insight into seasonal differences. Furthermore, telemetry studies are suitable to describe behaviour at a finer scale. In addition, exact dispersal routes might become visible.

Genetic methods are used to estimate population size (mini-satellites), but also to identify population structure (micro-satellites and mitochondrial DNA). This might permit inferences about connections between populations in and around Sihlwald, and shed light on where these red deer originally came from.

 

rempfler-biblio

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Donnerstag, 14 Juni 2018 08:28

Anadrome Fische

Anadrome Fische leben primär im Meer, wandern aber zur Laichablage aus dem Meer in Süßgewässer und suchen dort geeignete Laichplätze auf. Die Fische wandern bereits als Jungfische ins Meer zurück.

Beispiele: Maifisch, Atlantischer Stör, Waxdick, Lachs, Meerforelle.

 

anadrom-term

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Donnerstag, 14 Juni 2018 08:24

Katadrome Fische

Katadrome Fische sind Wanderfische, die den größeren Teil ihres Lebens im Süßwasser verbringen und  oft Tausende Kilometer von ihrem Heimatfluss entfernt liegende Laichplätze im Meer aufsuchen. Beispiel: Euopäischer Aal

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Evidence of climate change effects on within-winter movements of European mallards (Anas platyrhynchos).

Ibis 152: 600-609.

Abstract:

We analysed within‐winter (December–February) movements of Mallard using the EURING Data Bank. Most movements were directed towards the south or southwest during all three winter months. Distances covered increased with winter harshness and generally decreased from 1952 to 2004. Mallards appear to move less than other duck species during winter. Long‐distance movements of Mallards seem to be related to cold weather, birds only moving long distances in large numbers during the very coldest winters. Movements are not restricted during midwinter, but occur throughout the winter. The decreasing within‐winter movement over time (1952–2004) could be explained by decreasing reporting probabilities and/or warmer winters in recent decades. However, the first is only true if the decrease in reporting probability increases with distance moved, for which we found no indication in our study. Therefore, we suggest that the pattern found is evidence of long‐term winter warming reducing the distance of within‐winter movements in this species.

sauter-biblio

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© Peter Dollinger, Zoo Office Bern hyperworx