Search for dissertations about: "niche separation"

Showing result 1 - 5 of 14 swedish dissertations containing the words niche separation.

  2. 1. The evolutionary ecology of niche separation : Studies on the sympatric butterflies Leptidea sinapis and Leptidea reali

    Author : Magne Friberg; Wiklund Christer; John N. Thompson; Stockholms universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Lepidoptera; ecological character displacement; reproductive isolation; species discrimination; habitat; host plant; life history; sexual selection; female choice; Biology; Biologi; zoologisk ekologi; Animal Ecology;

    Abstract : Studies of ecology and evolution have become largely integrated, and increasing attention is paid to the role of ecology for speciation and post speciation divergence. In this thesis I have applied an in-depth approach studying the ecology of a butterfly species pair; the morphologically virtually identical sister-species, the Wood white (Leptidea sinapis) and Reál’s wood white (Leptidea reali). READ MORE

  4. 2. Genetic variation, clonal diversity and breeding system in sedges (Carex)

    Author : Olle Jonsson; Biologiska institutionen; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Systematic botany; Carex ericetorum; Carex caryophyllea; Carex bigelowii; Carex arenaria; phenology; niche; genet identification; clone size; isozyme; gene flow; introgression; allozyme; gene diversity; population genetics; taxonomy; morphology; phytogeography; chemotaxonomy. Physiology of nonvascular plants; Systematisk botanik; taxonomi; morfologi; kemotaxonomi. Växters fysiologi inte kärlväxter .;

    Abstract : In this thesis I investigate genetic variation in clonal plants within the wind-pollinated plant family Cyperaceae and, in particular, in species of Carex. Clonal diversity and the spatial distribution of clones (genets) within populations was investigated in Carex bigelowii (in Iceland and Scandinavia) and C. READ MORE

  5. 3. Ecology of parasitoids and their hosts in oilseed rape fields

    Author : Josef Berger; Biodiversitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; parasitoids; herbivores; oilseed rape; pollen beetle; cabbage stem weevil; parasitoid community; niche separation; landscape scale; community composition; landscape configuration; Species abundance distribution SAD models; dispersal; metacommunity;

    Abstract : Oilseed rape fields are a very common crop in the agricultural landscape of southern Sweden, and they can harbour surprisingly many insect species. Some of them are herbivores that feed on various parts of the oilseed rape plant, others are natural enemies of the herbivores, and even more species are tourists from the surrounding landscape. READ MORE

  6. 4. Variation in Pseudorchis albida s.l. (Orchidaceae) and Carex capitata s.l. (Cyperaceae) : Morphology, genetic diversity, ecology and systematics

    Author : Lars-Gunnar Reinhammar; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Ecology; Pseudorchis; Carex; morphologic variation; allozymes; immigration history; regeneration niche; biodiversity; ordinations; Ekologi; Terrestrial; freshwater and marine ecology; Terrestisk; limnisk och marin ekologi; systematisk botanik; Systematic Botany;

    Abstract : In the Scandinavian flora, several species-pairs where one member is an alpine species andthe other is a closely related lowland species, have been described. The aim of this studywas to investigate two such examples, viz. Pseudorchis albida s.s. READ MORE

  7. 5. Systematics, phylogeography and polyploid evolution in the Dactylorhiza maculata complex (Orchidaceae)

    Author : David Ståhlberg; Biologiska institutionen; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; ITS; morphometry; taxonomy; Systematic botany; Växtekologi; Plant ecology; vegetation analysis; recombination; polyploidy; plastid DNA; niche differentiation; chemotaxonomy. Physiology of nonvascular plants; morphology; phytogeography; hybrid zone; glacial refugia; Dactylorhiza; flow cytometry; Systematisk botanik; taxonomi; morfologi; kemotaxonomi. Växters fysiologi inte kärlväxter .;

    Abstract : The aim of this thesis was to investigate and describe different aspects of variation in the Dactylorhiza maculata complex and to relate the variation patterns to underlying biological processes such as Quaternary migration history, hybridization and polyploid evolution. The variation patterns were analysed at various geographic levels using molecular markers (plastid DNA and ITS of nrDNA), cytological data, morphometry and ecological data. READ MORE