http://www.bibsonomy.org/burst/group/feldhamsterBibSonomy BuRST Feed for /group/feldhamster2009-01-06T14:19:57+01:00SpringerLink - Zeitschriftenbeitraghttp://www.bibsonomy.org/bibtex/2ce8b240e6be4b25e4645e73cc12911ad/rebeccalangerebeccalange2008-11-25T11:51:25+01:00pholidoptera orthoptera crickets HabitatFragm modelling metapopulation <span style="color:#555555;">F. <a href="http://www.bibsonomy.org/author/Jordán">Jord&#225;n</a> and A. <a href="http://www.bibsonomy.org/author/Báldi">B&#225;ldi</a> and K.-M. <a href="http://www.bibsonomy.org/author/Orci">Orci</a> and I. <a href="http://www.bibsonomy.org/author/Rácz">R&#225;cz</a> and Z. <a href="http://www.bibsonomy.org/author/Varga">Varga</a> </span><em>Landscape Ecology</em><em>18(1):83--92</em><em>#jan#2003. </em>Tue Nov 25 11:51:25 CET 2008Landscape Ecology#jan#183--92Characterizing the importance of habitat patches and corridors in maintaining the landscape connectivity of a Pholidoptera transsylvanica (Orthoptera) metapopulation182003pholidoptera orthoptera crickets HabitatFragm modelling metapopulation Since the fragmentation of natural habitats is one of the most serious problems for many endangered species, it is highly interesting to study the properties of fragmented landscapes. As a basic property, landscape connectivity and its effects on various ecological processes are frequently in focus. First, we discuss the relevance of some graph properties in quantifying connectivity. Then, we propose a method how to quantify the relative importance of habitat patches and corridors in maintaining landscape connectivity. Our combined index explicitly considers pure topological properties and topographical measures, like the quality of both patches (local population size) and corridors (permeability). Finally, for illustration, we analyze the landscape graph of the endangered, brachypterous bush-cricket Pholidoptera transsylvanica. The landscape contains 11 patches and 13 corridors and is situated on the Aggtelek Karst, NE-Hungary. We characterize the importance of each node and link of the graph by local and global network indices. We show how different measures of connectivity may suggest different conservation preferences. We conclude, accordingly to our present index, by identifying one specific habitat patch and one specific corridor being in the most critical positions in maintaining connectivity. ER -http://www.bibsonomy.org/bibtex/2843ea4fe7ac7df9ef245ceabe57dbbf2/rebeccalangerebeccalange2008-09-03T10:59:27+02:00genetics allozymes speciesMobility conservation PopulationGenetics HabitatFragm geneticStructure <span style="color:#555555;">Byron C. <a href="http://www.bibsonomy.org/author/Wood">Wood</a> and Andrew S. <a href="http://www.bibsonomy.org/author/Pullin">Pullin</a> </span><em>Biodiversity and Conservation</em><em>11(8):1451--1468</em><em>#aug#2002. </em>Wed Sep 03 10:59:27 CEST 2008Biodiversity and Conservation#aug#81451--1468Persistence of species in a fragmented urban landscape: the importance of dispersal ability and habitat availability for grassland butterflies112002genetics allozymes speciesMobility conservation PopulationGenetics HabitatFragm geneticStructure Some species cope with, and survive in, urban areas better than others.From a conservation viewpoint it is important to understand why some species arerare or are excluded in the urban landscape, in order that we might take actionto conserve and restore species. Two ecological factors that might explain thedistribution and abundance of butterfly species in the urban landscape aredispersal ability and the availability of suitable habitat. The influence ofthese factors was assessed by examining the distribution and genetic structureof four grassland butterfly species in the West Midlands conurbation, UK. Thefour species differ in their distribution and abundance, mobility and habitatspecificity. No significant fit to the isolation-by-distance model was found forany of the study species at this spatial scale. MeanFST values revealed a non-significant level ofpopulation structuring for two species, Pieris napi (L.)and Maniola jurtina (L.), but moderate and significantpopulation differentiation for Pyronia tithonus (L.) andCoenonympha pamphilus (L.). Results suggest that thesespecies are limited more by the availability of suitable habitat than by theirability to move among habitat patches. Conservation strategies for thesegrassland species should initially focus on the creation and appropriatemanagement of suitable habitat. More sedentary species that have already beenexcluded from the conurbation may require a more complex strategy for theirsuccessful restoration. ER -Arbeit zeigt den Einfluss von Straßen auf die Bautenstrukturen von Hamstern in Hessen diesseits und jenseits von großen Straßen.http://www.bibsonomy.org/bibtex/2de1a87d0763967eac6357a152dd34db4/karinnadrowskikarinnadrowski2008-08-29T14:00:33+02:00Infrastruktur Melanie_Richter Straße Cricetus_cricetus Richter Hamster Melanie Bau <span style="color:#555555;">Melanie <a href="http://www.bibsonomy.org/author/Richter">Richter</a> </span><em>Professur f&#252;r Tier&#246;kologie, Justus-Liebig-Universit&#228;t, Gie&#223;en, </em>(<em>2008</em>)Fri Aug 29 14:00:33 CEST 2008Analyse räumlicher Zusammenhänge zum Feldhamster \it{Cricetus cricetus} in Hessen2008Infrastruktur Melanie_Richter Straße Cricetus_cricetus Richter Hamster Melanie Bau Eine einseitige Anleitung, wie eine Ooffice Literaturdatenbank aus JabRef oder BibSonomy exportiert und importiert werden kann.http://www.bibsonomy.org/bibtex/2d4841a7228ffc7a84eb0117b62b800b0/karinnadrowskikarinnadrowski2008-08-08T14:15:59+02:00OpenOffice Literaturverzeichnis BibSonomy literature Literatur JabRef <span style="color:#555555;">Karin <a href="http://www.bibsonomy.org/author/Nadrowski">Nadrowski</a> </span>(<em>2008</em>)Fri Aug 08 14:15:59 CEST 2008Anleitung Literaturverzeichnis Ooffice JabRef Bibsonomy2008OpenOffice Literaturverzeichnis BibSonomy literature Literatur JabRef http://www.bibsonomy.org/bibtex/248a7ba329b561e16fbb4ec584e38f36e/rebeccalangerebeccalange2008-07-18T14:25:32+02:00schätzer recapture metapopulation dispersal statistics <span style="color:#555555;">Klaus <a href="http://www.bibsonomy.org/author/Henle">Henle</a> and Bernd <a href="http://www.bibsonomy.org/author/Gruber">Gruber</a> </span>(<em>in prep</em>)Fri Jul 18 14:25:32 CEST 2008Erfassung und Analyse von Tierpopulationen - Eine Einführung in Methoden und Anwendungsmöglichkeiten im Naturschutzin prepschätzer recapture metapopulation dispersal statistics Inhaltsverzeichnis Vorwort 1 Einführung 2 Population und Metapopulation 2.1 Konzepte und Abgrenzung 2.2 Populationsparameter 3 Methodenwahl und Versuchsplanung 3.1 Methodenwahl und Anwendungsmöglichkeiten im Naturschutz 3.2 Versuchsplanung und Datenprotokollierung 4 Relative Häufigkeit 4.1 Generelle Grundlagen 4.2 Häufigkeitsindices 4.2.1 Zählungen von Tierspuren 4.2.2 Zählungen von Tieren 4.2.3 Fang von Tieren 4.3 Häufigkeitsklassen 4.4 Schätzmethoden 4.4.1 Linientaxierung und Punkt-Stop-Methoden 4.4.2 Nachweisfrequenzen 4.4.3 Nachbarschaftsdistanzen 4.5 Korrekturfaktoren 5 Absolute Häufigkeit 5.1 Vermutungen 5.2 Totalerfassung 5.2.1 Totalerfassung im Gesamtgebiet 5.2.2 Totalerfassung auf Probeflächen 5.2.2.1 Homogene Untersuchungsgebiete 5.2.2.2 Stratifizierte Erfassung in heterogenen Untersuchungsgebieten 5.3 Distanzerfassungen zur Schätzung von Populationsgröße und -dichte 5.3.1 Linientransektschätzungen 5.3.2 Punkt-Radius-Methode 5.4 Abfangen und Hinzufügen von Individuen 5.4.1 Selektives Abfangen und Hinzufügen (KELKER’s Methode) 5.4.2 Unselektives Abfangen (Fang-Aufwand- Methoden) 6 Reproduktion und Mortalität 6.1 Reproduktion 6.2 Lebenserwartung 6.3 Mortalität 6.4 Lebenstafeln 7 Markierung-Wiederfang-Analysen 7.1 Grundannahmen von Markierung- Wiederfang-Analysen 7.2 Geschlossene Populationen (Populationsgröße) 7.2.1 LINCOLN-PETERSEN-Schätzung 7.2.2 Fangfrequenzmodelle 7.2.3 BAYES’sche Schätzverfahren 7.2.4 Modell CAPTURE 7.3 Populationsdichte 7.4 Offene Populationen 7.4.1 Mindest-Populationsgröße und Mindest- Überlebensraten 7.4.2 JOLLY-SEBER-Modell 7.4.3 MANLY-PARR-Modell 7.4.4 Robuster Versuchsplan 7.4.5 Von der Tagespopulationsgröße zur Gesamtpopulationsgröße 7.4.6 Ringfund- und Jagdmarkenanalysen 7.4.7 Vergleich von Mortalitätsraten für unterschiedliche Zeiträume 7.4.8 Separation von Emigration und Mortalität 8 Aktivitätsraum und Dispersion 9 Artenzahl und relative Häufigkeit von Arten Appendix I - Bezugsquellen von Computerprogrammen Appendix II - Computerprogramme Literatur Stichwortverzeichnishttp://www.bibsonomy.org/bibtex/28c5a356c91c0ff9412afcf347641d26e/karinnadrowskikarinnadrowski2008-07-16T16:18:30+02:00scientific_communities SCOOP Wiki KnowWe BIOLOG <span style="color:#555555;">J. <a href="http://www.bibsonomy.org/author/Baumeister">Baumeister</a> and Jochen <a href="http://www.bibsonomy.org/author/Reutelshoefer">Reutelshoefer</a> and Fabian <a href="http://www.bibsonomy.org/author/Haupt">Haupt</a> and Karin <a href="http://www.bibsonomy.org/author/Nadrowski">Nadrowski</a> </span><em>Proceedings of 2nd Workshop on Scientific Communities of Practice (SCOOP), </em><em>Bremen, Germany, </em>(<em>2008</em>)Wed Jul 16 16:18:30 CEST 2008Bremen, GermanyProceedings of 2nd Workshop on Scientific Communities of Practice (SCOOP)Capture and Refactoring in Knowledge Wikis. Coping with the Knowledge Soup2008scientific_communities SCOOP Wiki KnowWe BIOLOG http://www.bibsonomy.org/bibtex/2936dde51342040786a9d14b2387605ae/karinnadrowskikarinnadrowski2008-07-11T11:31:04+02:00parasitism nematode <span style="color:#555555;">E. J. L. <a href="http://www.bibsonomy.org/author/Soulsby">Soulsby</a> </span><em>Lea &amp; Febiger, </em><em>Philadelphia, </em>(<em>1982</em>)Fri Jul 11 11:31:04 CEST 2008PhiladelphiaHelminths, Arthropods and Protozoa of Domesticated Animals1982parasitism nematode It's not the number, but length and fecundity that can be controlled by the hosthttp://www.bibsonomy.org/bibtex/2150b4bb5f000f90c44f08c3be4aa2ff5/karinnadrowskikarinnadrowski2008-07-11T11:23:40+02:00parasitism nematode sheep <span style="color:#555555;">M. J. <a href="http://www.bibsonomy.org/author/Stear">Stear</a> and K. <a href="http://www.bibsonomy.org/author/Bairden">Bairden</a> and J. L. <a href="http://www.bibsonomy.org/author/Duncan">Duncan</a> and P. H. <a href="http://www.bibsonomy.org/author/Holmes">Holmes</a> and Q. A. <a href="http://www.bibsonomy.org/author/McKellar">McKellar</a> and M. <a href="http://www.bibsonomy.org/author/Park">Park</a> and S. <a href="http://www.bibsonomy.org/author/Strain">Strain</a> and M. <a href="http://www.bibsonomy.org/author/Murray">Murray</a> and S. C. <a href="http://www.bibsonomy.org/author/Bishop">Bishop</a> and G. <a href="http://www.bibsonomy.org/author/Gettinby">Gettinby</a> </span><em>Nature</em><em>389(6646):27--27</em><em>September1997. </em>Fri Jul 11 11:23:40 CEST 2008NatureSeptember664627--27How hosts control worms3891997parasitism nematode sheep http://www.bibsonomy.org/bibtex/2148a8d041f00e574c304e22f36ae9789/melanie_richtermelanie_richter2008-07-08T14:29:55+02:00distributionendangered_species range_fragmentation <span style="color:#555555;">Agata <a href="http://www.bibsonomy.org/author/Banaszek">Banaszek</a> and Joanna <a href="http://www.bibsonomy.org/author/Ziomek">Ziomek</a> </span><em>Folia Zoologica</em><em>56(3):235-242</em>(<em>2007</em>)Tue Jul 08 14:29:55 CEST 2008Folia Zoologica 3235-242 The common hamster, Cricetus cricetus in Poland: status and current range562007distributionendangered_species range_fragmentation The current range and distribution of the common hamster, Cricetus cricetus in Poland was established. The range of the species has dwindled substantially in the course of just 30 years and the process is still going on. The Polish populations are isolated from the Belarussian, Czech and German ones, there is low probability of some exchange with Ukrainian hamsters. Moreover, two main areas of hamster distribution in Poland are isolated from each other. In view of the marked shrinkage and fragmentation of the range, we propose changing the status of this species in Poland from unknown (DD) to endangered (EN).http://www.bibsonomy.org/bibtex/226cd51addc15f2ca6b3957e6d7ab5d66/melanie_richtermelanie_richter2008-07-08T14:28:31+02:00habitat fragmentation common bottleneck hamster <span style="color:#555555;">K. <a href="http://www.bibsonomy.org/author/Neumann">Neumann</a> and H. <a href="http://www.bibsonomy.org/author/Jansman">Jansman</a> and A. <a href="http://www.bibsonomy.org/author/Kayser">Kayser</a> and S. <a href="http://www.bibsonomy.org/author/Maak">Maak</a> and R. <a href="http://www.bibsonomy.org/author/Gattermann">Gattermann</a> </span><em>Conservation genetics</em><em>5(2):181-193</em><em>March2004. </em><em>DOI: 10.1023/B:COGE.0000030002.01948.b3 . </em>Tue Jul 08 14:28:31 CEST 2008Conservation geneticsMarchDOI: 10.1023/B:COGE.0000030002.01948.b32181-193Multiple bottlenecks in threatened western European populations of the common hamster Cricetus cricetus (L.)52004habitat fragmentation common bottleneck hamster Common hamsters Cricetus cricetus (L.)show a highly fragmented distributionpattern across Europe. Over the last decades,human influence caused significant populationdeclines in particular at the western rangeboundary. Despite the initiation of breedingand release programs the genetic structure anddiversity of European common hamsterpopulations is largely unknown. In this study,hamsters from ten localities in five Europeancountries were investigated. Mitochondrialcontrol region was sequenced from 145 animalsrepresenting all sampled populations. 385hamster were screened for polymorphisms at 11microsatellite loci. Both marker systemsrevealed extensive genetic differentiationamong European common hamsters. Westernpopulations displayed very low levels of mtDNAdiversity (H = 0 – 0.2, Alsace, Limburg,Flanders, Baden-Wuerttemberg) compared toeastern populations from Saxony-Anhalt,Thuringia and Southern Moravia (H = 0.663– 0.816). Microsatellite analyses revealed asimilar pattern with low to moderate diversityvalues in western hamsters (A = 1.636 –5.364; H e = 0.111 – 0.504) and highlevels of polymorphism in eastern hamsters(A = 8.909 – 9.818; H e = 0.712– 0.786). High microsatellite based F STmeasures (up to 0.635) suggest a typical islandmodel of distribution with no current gene flowbetween most areas. Western hamster populationsexhibit obvious similarities in mitochondrialhaplotype and microsatellite alleledistributions. Gene trees group westernhamsters consistently together on the samebranch but bootstrap values never reachedsignificance. There are strong indications thatlow diversity in western populations ispartially caused by a joint historic founderevent and not only by recent population breakdowns. Overlapping mitochondrial haplotypesprove a close association between westernhamsters and animals from the east German rangein the recent past which does not support theexistence of a separate subspecies C. c.canescens in Europe. Hamsters from southernMoravia emerged as the genetically mostdistinguished population and could be part of a different genetic lineage in Europe.http://www.bibsonomy.org/bibtex/264e5ac6c5de7263b3fced6cb05f38c3f/melanie_richtermelanie_richter2008-07-08T14:28:02+02:00Mammals epidemiological Fragmentation <span style="color:#555555;">Gerardo <a href="http://www.bibsonomy.org/author/Suzan">Suzan</a> and Anibal <a href="http://www.bibsonomy.org/author/Armien">Armien</a> and James N. <a href="http://www.bibsonomy.org/author/Mills">Mills</a> and Erika <a href="http://www.bibsonomy.org/author/Marce">Marce</a> and Gerardo <a href="http://www.bibsonomy.org/author/Ceballos">Ceballos</a> and Mario <a href="http://www.bibsonomy.org/author/Avila">Avila</a> and Jorge <a href="http://www.bibsonomy.org/author/Salazar-Bravo">Salazar-Bravo</a> and Luis <a href="http://www.bibsonomy.org/author/Ruedas">Ruedas</a> and Blas <a href="http://www.bibsonomy.org/author/Armien">Armien</a> and Terry L. <a href="http://www.bibsonomy.org/author/Yates">Yates</a> </span><em>Journal of Mammalogy</em><em>89(3):684–690</em><em>June2008. </em>Tue Jul 08 14:28:02 CEST 2008Journal of MammalogyJune3684–690 Epidemiological considerations of rodent community composition in fragmented landscapes in Panama892008Mammals epidemiological Fragmentation We predicted that more-fragmented habitats are associated with lower diversity of small mammals and higher densities of populations of rodents that are hosts of hantaviruses. We compared diversity and distribution of small mammals that are either hosts or nonhosts of hantaviruses in 6 Panamanian national parks and adjacent areas with varying degree of human impacts. We sampled forest, edge, and anthropogenically disturbed habitats. The generalist rodents Oligoryzomys fulvescens (reservoir of Choclo virus) and Zygodontomys brevicauda (reservoir of Calabazo virus) were more abundant in disturbed habitats, especially in smaller and more isolated patches, where population density and diversity of other rodent species was lowest. In contrast, these 2 species had lower abundances in larger forested areas with more nonreservoir species of small mammals. Our results suggest that the change in the natural environment resulting from tropical deforestation is increasing the abundance and distribution of species that are reservoirs for hantaviruses. Therefore, it is likely that forest fragmentation has contributed to recent outbreaks of hantavirus pulmonary syndrome in tropical areas. Conservation of natural resources becomes all the more imperative, not only for protecting fauna and flora but also for human health.http://www.bibsonomy.org/bibtex/2e8e09612d4f56b1ae88a7a805a2ce627/melanie_richtermelanie_richter2008-07-08T14:27:08+02:00Hamsterschutz Boden Bauverteilung Vorkommen <span style="color:#555555;">Anja <a href="http://www.bibsonomy.org/author/Weidling">Weidling</a> and Michael <a href="http://www.bibsonomy.org/author/Stubbe">Stubbe</a> </span><em>Naturschutz und Landschaftspflege in Brandenburg</em>(<em>1998</em>)Tue Jul 08 14:27:08 CEST 2008Naturschutz und Landschaftspflege in Brandenburg18-21Feldhamstervorkommen in Abhängigkeit vom Boden11998Hamsterschutz Boden Bauverteilung Vorkommen http://www.bibsonomy.org/bibtex/27d7907b41bafdcc4e03936f1f94f491e/rebeccalangerebeccalange2008-07-07T14:25:15+02:00genetics microsatellites GenotypingErrors <span style="color:#555555;">Alexander <a href="http://www.bibsonomy.org/author/Kiewert">Kiewert</a> </span><em>Universit&#228;t zu L&#252;beck - Institut f&#252;r Medizinische Biometrie und Statistik, </em>(<em>2006</em>)Mon Jul 07 14:25:15 CEST 2008Empfehlungen zur Qualitätssicherung von Genotypisierungsdaten bei familienbasierten Studien mit Mikrosatelliten2006genetics microsatellites GenotypingErrors Life history strategy and ecosystem impact of a small mammal herbivore in a mountain steppehttp://www.bibsonomy.org/bibtex/2af6da0c7c096dd2cbd219a77114765cb/karinnadrowskikarinnadrowski2008-07-05T21:46:11+02:00pika Nadrowski Gobi Mongolia dissertation Ochotona_pallasi Ochotona <span style="color:#555555;">Karin <a href="http://www.bibsonomy.org/author/Nadrowski">Nadrowski</a> </span><em>Fachbereich Geographie, Universit&#228;t Marburg, </em>(<em>2006</em>)Sat Jul 05 21:46:11 CEST 2008Life history strategy and ecosystem impact of a small mammal herbivore in a mountain steppe2006pika Nadrowski Gobi Mongolia dissertation Ochotona_pallasi Ochotona Kurzfassung in Englisch: Pikas (genus Ochotona) were suspected to possibly behave as „small mammal pests" in the mountain steppes of the Gobi Gurvan Saikhan National Conservation Park (GGS) in the Mongolian Gobi Altai. The present study shows that the Mongolian pika (Ochotona pallasi pricei ), a subspecies of the Pallas pika, is the dominant small mammal species in the mountain steppes of the GGS. It outnumbered other small mammals by one order of magnitude and outweighed them by two of them. Data on capture and observation are available for three summers and one winter from a trapping grid of 100x100m2, including a summer of drought. Data based on observation was more reliable in terms of encounter success than data based on capture. Captured juveniles were discriminated from adults using information on the development of their weight. An average adult weight was estimated to range between 180 and 200 g. Possible scenarios for dynamics of population densities were simulated using a system of Leslie-matrices based on estimates for survival and reproduction of the observed individuals. Survival rates were estimated using maximum likelihood techniques with competing models for survival and recapture probabilities. The most parsimonious model included effects of population density, age, and sex on survival, while there was no effect of cohort affiliation nor climatic factors season and drought. Generally, adults showed higher survival rates than juveniles, females showed higher survival rates than males, and survival declined with density. Estimates for reproduction were based on the observations of litter number and size, resulting in a maximum of 13 juveniles per female pika. Simulated population densities were similar to the measured population densities, but did not reflect the effects of the year of drought. Population densities were measured using pooled data from capture and observation sessions. In the study period pika densities varied between 14.6 and 49.8 individuals per ha. Median density was 21.4 animals, which is less than the 28 burrows on the trapping site. Lowest densities were reached one year after the summer of drought, indicating a time lag of one year in the response to the drought conditions. Comparing reproductive effort, factors influencing survival rates, and density dynamics of the Mongolian pika with other species of the genus shows that this species exhibits traits of the group of non-burrowing pikas, which are closer to a K-type of life history strategy than the group of burrowing pikas. Density dependent survival indicates that burrow possession may be crucial for survival. Ecosystem impact of the pikas was assessed studying the productivity of the burrow habitat in comparison to steppe habitat together with the effect of grazing by pikas and by larger herbivores. Productivity and biomass removal was measured using exclosure plots on burrow and steppe habitat. Burrows showed higher productivity than steppe habitats when water availability was higher. The grass Agropyron cristatum profited most from the burrow habitat in terms of biomass and quality. This grass is an important fodder plant for livestock. An effect of livestock grazing was missed by the experiment. The productivity of the vegetation was controlled by the availability of moisture, not by pika grazing, although individual pikas removed more biomass, when it was available. This biomass is probably stored in the burrows. Pikas preferentially grazed Agropyron cristatum on burrow plots. Burrows were estimated to last 120 years at least. The studied system behaved according to the prediction based on the non-equilibrium theory of rangeland dynamics: plant productivity was controlled by climatic conditions, as was the density of the herbivores. However, although pika densities varied, there were upper and lower limits to this variation made possible by the territorial behaviour of the animals. Possession of territories together with harvesting plant material enables the species to mitigate climatic inter-annual variability. Pika burrow densities were controlled by altitude and thus probably by the longterm availability of plant biomass. Livestock densities had only a small effect on burrow densities. However, this effect changed at the pediment angle separating pediments from the mountain ranges, indicating a change of system behaviour. The present study shows that the Mongolian pika cannot be seen as „small mammal pest" species, since its densities are controlled by the availability of burrows and it has a positive influence on pasture quality. Kurzfassung in Deutsch: Kleinsäuger der Gattung Pfeifhasen (Ochotona) wurden verdächtigt, als „Plagen" in den Bergsteppen des Gobi Gurvan Saikhan Nationalparks im mongolischen Gobi Altai aufzutreten. Die vorliegende Arbeit zeigt dass der Mongolische Pfeifhase (Ochotona pallasi pricei), eine Unterart des Pallas Pfeifhasen, die dominierende Kleinsäugerart in den Bergsteppen des GGS ist. Sie übertrifft die anderen Kleinsäuger um eine Größenordnung in der Anzahl und um zwei Größenordnungen im Gewicht. Über den Zeitraum von drei Sommern und einem Winter wurden vom Jahr 2000 bis zum Jahr 2002 Informationen zu den markierten Tieren mithilfe von Fallenfang und Beobachtung auf einer 100x100m2 großen Untersuchungsfläche gesammelt. Der Zeitraum der Untersuchungen schloss eine strenge Dürre im Sommer 2001 mit ein. Juvenile Tiere konnten aufgrund ihrer Gewichtsentwicklung von Adulten unterschieden werden. Ein durchschnittliches Adultgewicht wurde zwischen 180 und 200 g geschätzt. In einem Matrixmodell der Populationsdynamik wurden Ergebnisse zu Überlebensraten und Reproduktionsraten der beobachteten Individuen zusammengefasst. Überlebensraten wurden mit Maximum-Likelihood-Methoden ermittelt, wobei verschiedene Modelle mit Überlebens- und Wiederfangraten miteinander konkurrierten. Das sparsamste Modell beinhaltete Populationsdichte, Alter, und Geschlecht als Einflussgrößen für Überlebensraten, nicht aber die Zugehörigkeit zu einer bestimmten Kohorte oder die klimatischen Faktoren Saisonalität und Dürre. Generell zeigten adulte Tiere höhere Überlebensraten als juvenile, Weibchen höhere als Männchen und die Überlebensrate sank mit der Populationsdichte. Reproduktionsraten wurden basierend auf Beobachtungen zur Anzahl und Größe der Würfe geschätzt. Dies ergab einen Median von drei Juvenilen und ein Maximum von dreizehn Juvenilen pro Weibchen. Obwohl die simulierten und die gemessenen Populationsdichten vergleichbare Größenordnungen hatten, konnten das Matrixmodell die Auswirkungen der Dürre auf die Populationsdichte nicht abbilden. Populationsdichten wurden mithilfe der aus Fang und Beobachtung zusammengelegten Daten gemessen. Populationsdichten schwankten zwischen 14.6 und 49.8 Individuen pro ha. Der Median der Dichten lag mit 21.4 Tieren unterhalb der Anzahl der Bauten auf der Untersuchungsfläche (28 Bauten pro ha). Die niedrigsten Dichten wurden im Jahr nach der Dürre gemessen. Dies macht einen Verzögerungseffekt der Dürrebedingungen um ein Jahr wahrscheinlich. Werden reproduktiver Einsatz, die Einflussgrößen der Überlebensraten und die Entwicklung der Populationsdichten des Mongolischen Pfeifhasen verglichen mit dem anderer Arten der Gattung, so zeigt diese Art Eigenschaften aus der Gruppe der „nichtgrabenden" Pfeifhasen, die näher einem K-Typ von Überlebensstrategien stehen. Die Dichteabhängigkeit der Überlebensraten legt nahe, dass der Besitz eines Baus entscheidend für das Überleben von Individuen ist. Über die Produktivität der Bauten im Vergleich zur Steppe wurde der Einfluss der Pfeifhasen auf das Ökosystem abgeschätzt. Gleichzeitig wurde die Beweidung durch Pfeifhasen und größere Herbivoren untersucht. Dazu wurde ein Ausschlussexperiment genutzt. Auf Bauten war die Produktivität dann höher, wenn auch mehr Feuchtigkeit vorhanden war. Das Gras Agropyron cristatum profitierte am meisten von den Bedingungen auf Bauten bezüglich Biomassezuwachs und Qualität der Biomasse. Eine Beweidung durch größere Herbivore konnte von diesem Experiment nicht nachgewiesen werden. Pfeifhasen ernteten zwischen 10 und 35% der vorhandenen Biomasse, wobei Agropyron cristatum auf den Bauten bevorzugt wurde. Der Biomassezuwachs der Vegetation wurde allerdings vom Niederschlag begrenzt, nicht durch den Effekt der Beweidung. Das untersuchte Ökosystem bestätigte die Vorhersagen, die auf der Theorie einer Nichtgleichgewichtsdynamik von Weideland basieren: Sowohl die Produktivität der Vegetation als auch die Dichte der Herbivoren wurde von der klimatischen Variabilität kontrolliert. Allerdings variierten die Pfeifhasendichten nicht stark, es gab untere und obere Grenzen der Schwankungen. Diese Grenzen werden durch das territoriale Verhalten der Tiere ermöglicht. Der Besitz eines Territoriums zusammen mit dem Ernten pflanzlicher Biomasse ermöglicht es der Art, die Auswirkungen der inter-annuellen klimatischen Variabilität zu mildern. Eine Bauten-Lebensdauer wurde auf mindestens 120 Jahren geschätzt. Bautendichten von Pfeifhasen wurden von der Höhenlage beeinflusst und damit wahrscheinlich von der Langzeitverfügbarkeit von Biomasse. Viehdichten dagegen haben nur einen kleinen Einfluss auf Bautendichten von Pfeifhasen. Mongolische Pfeifhasen (Ochotona pallasi pricei) kommen somit nicht als „Kleinsäugerplage" in Betracht, da ihre Populationsdichten durch die Anzahl der Bauten begrenzt werden und sie die Weidequalität positiv beeinflussen.http://www.bibsonomy.org/bibtex/238a4f6c9ccc5c8629b0566da9a44ca61/melanie_richtermelanie_richter2008-07-03T13:13:24+02:00sex-biased_parasitism helminths <span style="color:#555555;">Blackwell <a href="http://www.bibsonomy.org/author/Publishing">Publishing</a> (eds.). </span><em>Journal of Avian Biology</em><em>39(3):272-276</em><em>May2008. </em><em>DOI: 10.1111/j.2008.0908-8857.04340.x . </em>Thu Jul 03 13:13:24 CEST 2008Journal of Avian BiologyMayDOI: 10.1111/j.2008.0908-8857.04340.x 3272-276Male-biased parasitism by common helminths is not explained by sex differences in body size or spleen mass of breeding cormorants Phalacrocorax auritus392008sex-biased_parasitism helminths In vertebrates, males are often more parasitised than conspecific females. This bias in parasitism might result from sex differences in parasite exposure and/or susceptibility to infection. Such information is important for testing hypotheses about allocation of resources to life histories of males and females and for testing hypotheses about factors thought to influence parasite fitness and parasite dynamics. We tested whether double-crested cormorants Phalacrocorax auritus exhibit male-biased parasitism by gut helminths. The prevalence of nematode Contracaecum spp. and trematode Drepanocaphalus spathans infections was similar to 90% and 39%, respectively. Cestode, primarily Paradilepis caballeroi and acanthocephalan Andracantha gravida infections were less common (< 10%). Male and female cormorants did not differ in prevalence of infection by any helminth species. However, males had twice the abundance and intensity of Contracaecum spp. infections and twice the intensity of D. spathans infections than found in females. For common parasites showing male-biased parasitism, degree of parasitism was also unrelated to body size or mass in either sex. Males and females did not differ in spleen mass and spleen mass was unrelated to abundance of common parasites. Furthermore, abundance of trematodes and nematodes was not correlated. At present, male biases in parasitism by nematodes and trematodes in cormorants are independent patterns that remain unexplained, but are most likely attributable to sex differences in exposure and/or immunological differences not yet assessed.http://www.bibsonomy.org/bibtex/24c12c72804222a6c2877b8f7fd698084/karinnadrowskikarinnadrowski2008-07-03T11:01:43+02:00species_richness species_accumulation species_area_relationship diversity Gotelli rarefaction <span style="color:#555555;">N. J. <a href="http://www.bibsonomy.org/author/Gotelli">Gotelli</a> and R. K. <a href="http://www.bibsonomy.org/author/Colwell">Colwell</a> </span><em>Ecol. Lett.</em><em>4(4):379 - 391</em>(<em>2001</em>)Thu Jul 03 11:01:43 CEST 2008Ecol. Lett.4379 - 391Quantifying biodiversity: procedures and pitfalls in the measurement and comparison of species richness42001species_richness species_accumulation species_area_relationship diversity Gotelli rarefaction Species richness is a fundamental measurement of community and regional diversity, and it underlies many ecological models and conservation strategies. In spite of its importance, ecologists have not always appreciated the effects of abundance and sampling effort on richness measures and comparisons. We survey a series of common pitfalls in quantifying and comparing taxon richness. These pitfalls can be largely avoided by using accumulation and rarefaction curves, which may be based on either individuals or samples. These taxon sampling curves contain the basic information for valid richness comparisons, including category-subcategory ratios (species-to-genus and species-to-individual ratios). Rarefaction methods - both sample-based and individual-based - allow for meaningful standardization and comparison of datasets. Standardizing data sets by area or sampling effort may produce very different results compared to standardizing by number of individuals collected, and it is not always clear which measure of diversity is more appropriate. Asymptotic richness estimators provide lower-bound estimates for taxon-rich groups such as tropical arthropods, in which observed richness rarely reaches an asymptote, despite intensive sampling. Recent examples of diversity studies of tropical trees, stream invertebrates, and herbaceous plants emphasize the importance of carefully quantifying species richness using taxon sampling curves.http://www.bibsonomy.org/bibtex/282a4d6a25e84f3205d8a41398ec17514/karinnadrowskikarinnadrowski2008-07-03T10:58:59+02:00species_accumulation additive_partitioning species_area_relationship diversity biodiversity rarefaction <span style="color:#555555;">Thomas O. <a href="http://www.bibsonomy.org/author/Crist">Crist</a> and Joseph A. <a href="http://www.bibsonomy.org/author/Veech">Veech</a> </span><em>Ecology Letters</em><em>9(8):923-932</em>(<em>2006</em>)Thu Jul 03 10:58:59 CEST 2008Ecology Letters8923-932Additive partitioning of rarefaction curves and species-area relationships: unifying alpha, betha- and gamma-diversity with sample size and habitat areas92006species_accumulation additive_partitioning species_area_relationship diversity biodiversity rarefaction Abstract Additive partitioning of species diversity is widely applicable to different kinds of sampling regimes at multiple spatial and temporal scales. In additive partitioning, the diversity within and among samples (alpha and beta) is expressed in the same units of species richness, thus allowing direct comparison of alpha and beta. Despite its broad applicability, there are few demonstrated linkages between additive partitioning and other approaches to analysing diversity. Here, we establish several connections between diversity partitions and patterns of habitat occupancy, rarefaction, and species-area relationships. We show that observed partitions of species richness are equivalent to sample-based rarefaction curves, and expected partitions from randomization tests are approximately equivalent to individual-based rarefaction. Additive partitions can also be applied to species-area relationships to determine the relative contributions of factors influencing the beta-diversity among habitat fragments.Birds and serviceshttp://www.bibsonomy.org/bibtex/2f3303fc285289e06d2ef9ae429633b20/karinnadrowskikarinnadrowski2008-07-03T10:35:35+02:00bird ecoystem biodiversity bird_decline extinction seeds forest ecology pollination dispersal <span style="color:#555555;">C. H. <a href="http://www.bibsonomy.org/author/Sekercioglu">Sekercioglu</a> and G. C. <a href="http://www.bibsonomy.org/author/Daily">Daily</a> and P. R. <a href="http://www.bibsonomy.org/author/Ehrlich">Ehrlich</a> </span><em>Proceedings Of The National Academy Of Sciences Of The United States Of America</em><em>101(52):18042--18047</em><em>December2004. </em>Thu Jul 03 10:35:35 CEST 2008Proceedings Of The National Academy Of Sciences Of The United States Of AmericaDecember5218042--18047Ecosystem consequences of bird declines1012004bird ecoystem biodiversity bird_decline extinction seeds forest ecology pollination dispersal We present a general framework for characterizing the ecological and societal consequences of biodiversity loss and applying it to the global avifauna. To investigate the potential ecological consequences of avian declines, we developed comprehensive databases of the status and functional roles of birds and a stochastic model for forecasting change. Overall, 21% of bird species are currently extinction-prone and 6.5% are functionally extinct, contributing negligibly to ecosystem processes. We show that a quarter or more of frugivorous and omnivorous species and one-third or more of herbivorous, piscivorous, and scavenger species are extinction-prone. Furthermore, our projections indicate that by 2100, 6-14% of all bird species will be extinct, and 7-25% (28-56% on oceanic islands) will be functionally extinct. Important ecosystem processes, particularly decomposition, pollination, and seed dispersal, will likely decline as a result.http://www.bibsonomy.org/bibtex/2e3ac77e738e482dfd2cd7a33f69317dd/karinnadrowskikarinnadrowski2008-07-02T17:20:52+02:00predator biodiversity biodiversity_surrogates biodiversity_loss birds <span style="color:#555555;">Mar <a href="http://www.bibsonomy.org/author/Cabeza">Cabeza</a> and Anni <a href="http://www.bibsonomy.org/author/Arponen">Arponen</a> and Astrid Van <a href="http://www.bibsonomy.org/author/Teeffelen">Teeffelen</a> </span><em>Journal of Applied Ecology</em><em>45(3):976--980</em>(<em>2008</em>)Wed Jul 02 17:20:52 CEST 2008Journal of Applied Ecology3976--980Top predators: hot or not? A call for systematic assessment of biodiversity surrogates452008predator biodiversity biodiversity_surrogates biodiversity_loss birds Sergio et al. (2006) argue that top predators are justified conservation surrogates based on a case study where raptor presence is associated with high species richness of birds, butterflies and trees. We question the methodology as well as the applicability of their results, and clarify differences between surrogates for biodiversity hotspots and surrogates for complementarity. We show that the results from Sergio et al. related to richness hotspots are not fully reliable and that the ability of top predators to identify complementary areas is not demonstrated. Given that complementarity-based surrogate studies have produced mixed results for a variety of reasons, we clarify some methodological misunderstandings while encouraging further testing of functional groups as biodiversity surrogates. Synthesis and applications. We call for caution in making generalizations, and emphasize that case studies on the use of surrogates should be conducted in a systematic manner. This will facilitate robust assessment across studies regarding the usefulness of particular species groups as biodiversity surrogates. Journal of Applied Ecology (2007) doi: 10.1111/j.1365-2664.2007.01364.xBrehm Buch über Hamsterhttp://www.bibsonomy.org/bibtex/2de823dfe1a7f27cd71c993ce26749984/melanie_richtermelanie_richter2008-07-02T15:16:44+02:00CricetusCricetus Hamster <span style="color:#555555;">Ulrich <a href="http://www.bibsonomy.org/author/Weinhold">Weinhold</a> and Anja <a href="http://www.bibsonomy.org/author/Kayser">Kayser</a> </span><em>Neue Brehm-B&#252;cherei </em><em>Westarp Wissenschaften-Verlagsgesellschaft GmbH, </em><em>Hohenwarsleben, </em>(<em>2006</em>)Wed Jul 02 15:16:44 CEST 2008HohenwarslebenNeue Brehm-BüchereiDer Feldhamster2006CricetusCricetus Hamster