Sökning: "delayed dispersal"

Visar resultat 1 - 5 av 6 avhandlingar innehållade orden delayed dispersal.

  1. 1. Cooperative Breeding in the Southern Anteater-Chat : Sexual Disparity, Survival and Dispersal

    Författare :Jonathan Barnaby; Jan Ekman; Anssi Laurila; Rita Covas; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Southern anteater-chat; Myrmecocichla formicivora; cooperative breeding; social evolution; behavioural ecology; delayed dispersal; family living; Africa; Biologi med inriktning mot populationsbiologi; Biology with specialization in Population Biology;

    Sammanfattning : Group-living sets the scene for complex social behaviours such as cooperative breeding, and exploring the factors that shape group-living is crucial in understanding these behaviours. This thesis explores the ecology of a population of the facultative cooperative breeding southern anteater-chat (Myrmecocichla formicivora), a group-living bird species endemic to southern Africa. LÄS MER

  3. 2. Plant community assembly and biodiversity: a spatio-temporal perspective

    Författare :Oliver Purschke; Biodiversitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; phylogenetic diversity; null model; life-history traits; land use history; landscape fragmentation; dispersal; functional diversity; semi-natural grasslands;

    Sammanfattning : Biodiversity, the variety of life at all organisational levels from genes to ecosystems, affects ecosystem processes and therefore the goods and services ecosystems provide. More research is needed to provide new insights into biodiversity changes and the processes that drive these changes, in order to formulate effective policy and conservation measures to stop the ongoing biodiversity loss. LÄS MER

  4. 3. The Nepotistic Parent; Predator Protection, Kinship and Philopatry

    Författare :Michael Griesser; Jan Ekman; Ronald Mumme; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Biology; referential alarm calls; delayed dispersal; nepotism; vigilance; alarm calling; mobbing; extended parental care; families; Perisoreus infaustus; Siberian jay; Biologi; Biology; Biologi; populationsbiologi; Population Biology;

    Sammanfattning : Evolution is fuelled by independent reproduction events. Yet, the offspring of at least three percent of all bird species postpone dispersal and forego independent reproduction. LÄS MER

  5. 4. Behaviour and life-history responses to chick provisioning under risk of nest predation

    Författare :Sönke Eggers; David Winkler; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Biology; Chick provisioning; clutch size; delayed dispersal; nest concealment; nest predation; parental care; population decline; Perisoreus infaustus; Siberian jay; Biologi; Biology; Biologi; populationsbiologi; Population Biology;

    Sammanfattning : This thesis examines risk management in breeding Siberian jays (Perisoreus infaustus), which is indigenous to the northern taiga. Parent behaviour and the nest are cryptic. A new nest is built each year. It is placed on spruce or pine branches close to the trunk and well insulated with lichens, feathers and reindeer hair. LÄS MER

  7. 5. Effects of Habitat Quality on Behavioural Decisions and Population Dynamics in the Siberian Jay

    Författare :Magdalena Nystrand; Jan Ekman; Erik Matthysen; Uppsala universitet; []
    Nyckelord :Biology; Perisoreus infaustus; relatedness; delayed dispersal; predation risk; foraging; trade-off; demography; source-sink dynamics; forest structure; Biologi;

    Sammanfattning : The dynamics of natural populations may be influenced by a variety of factors, ranging from feeding interference and territoriality to the risk of predation and climatic effects. The relative influence of these factors may be contingent upon the quality of the habitat in which individuals reside. LÄS MER