Sökning: "Alpine"

Visar resultat 21 - 25 av 62 avhandlingar innehållade ordet Alpine.

1. 21. Herbivory and plant community structure in a subarctic altitudinal gradient

   Författare :Jon Moen; Nancy Huntly; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; arctic and alpine vegetation; competition; exclosures; lemmings; plant defences; plant-plant interactions; Ranunculus glacialis; snow-bed; structuring factors; tall herb meadow; vertebrate grazing; voles;

   Sammanfattning : The object of this thesis was to study plant community structure, especially in relation to vertebrate herbivory, in an altitudinal gradient in the Fennoscandian mountain chain.A sowing experiment in a high alpine Ranunculus glacialis population showed that seeds germinated better in cleared microsites than under established individuals. LÄS MER

3. 22. Chemical and isotopic records of polycyclic histories in a subducted continental crust (Dora-Maira Massif, Western Alps)

   Författare :Francesco Nosenzo; Paola Manzotti; Alasdair Skelton; Charlotte Möller; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Subduction; continental crust; polycyclic; garnet; metamorphic petrology; Geology; geologi;

   Sammanfattning : At convergent plate margin, part of the continental crust can be subducted and exhumed. During continental subduction a pre-existing crust is reworked. Remnants of an older orogen are recycled and subjected to (ultra)-high-pressure metamorphism. LÄS MER

4. 23. Population Differentiation in Solidago virgaurea along Altitudinal Gradients

   Författare :Anna Bergsten; Jon Ågren; Staffan Karlsson; Kari Lehtilä; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; population differentiation; altitudinal gradient; plant nutrient status; resorption efficiency; resorption proficiency; flowering phenology; countergradient variation; reproductive effort; flower production; cost of reproduction; Biology; Biologi; Other biology; Övrig biologi; Ecological Botany; Ekologisk botanik;

   Sammanfattning : Altitudinal gradients offer attractive opportunities for studies of population differentiation in response to environmental heterogeneity. In this thesis, I examined population differentiation along altitudinal gradients by combining common-garden experiments with field studies and experiments in alpine, subalpine and boreal populations of the perennial herb Solidago virgaurea. LÄS MER

5. 24. Mountain vegetation in the Faroe Islands in a climate change perspective

   Författare :Anna Maria Fosaa; Biologiska institutionen; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; klimatologi; marklära; Växtekologi; Fysisk geografi; climatology; cartography; pedology; geomorphology; climate change.; Physical geography; Raunkiær´s life-forms; biodiversity; Vegetation zones; plant communities; Plant ecology; kartografi; geomorfologi;

   Sammanfattning : This thesis is a study of the mountain vegetation in the Faroe Islands based on five altitudinal transects sampled during the period 1999-2001. The vegetation was studied on the basis of plant communities, life-forms and biodiversity of vascular plant species and is discussed in a climate change perspective. LÄS MER

7. 25. Plant-Animal Interactions and Evolution of Floral Display and Flowering Phenology in Arabidopsis lyrata

   Författare :Saskia Sandring; Jon Ågren; Johan Ehrlén; José Gómez; Uppsala universitet; []
   Nyckelord :Ecology; Arabidopsis lyrata; natural selection; floral display; phenology; flowering time; plant-animal interactions; pollination; herbivory; selection gradients; population differentiation; local adaptation; Ekologi;

   Sammanfattning : In this thesis, I combined comparative and experimental approaches to examine selection on reproductive traits, and population differentiation in the insect-pollinated, outcrossing, perennial herb Arabidopsis lyrata. More specifically, I (1) determined whether selection on flowering phenology and floral display can be attributed to interactions with pollinators and herbivores, (2) examined whether population differentiation in flowering phenology and floral display is correlated with current selection on these traits, and (3) tested for local adaptation from contrasting environments in Europe. LÄS MER