Sökning: "seed plants"

Visar resultat 1 - 5 av 103 avhandlingar innehållade orden seed plants.

1. 1. Seed mobility and connectivity in changing rural landscapes

   Författare :Alistair G. Auffret; Sara Cousins; Robin Pakeman; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Biodiversity; Conservation; Functional connectivity; Historical ecology; Human-mediated dispersal; Invasive species; Landscape Ecology; Long-distance dispersal; Restoration; Seed bank; Seed dispersal; Seed rain; Structural connectivity; Physical Geography; naturgeografi;

   Sammanfattning : The success or failure of many organisms to respond to the challenges of habitat destruction and a warming climate lies in the ability of plant species to disperse between isolated habitats or to migrate to new ranges. European semi-natural grasslands represent one of the world's most species-rich habitats at small scales, but agricultural intensification during the 20th century has meant that many plant species are left only on small fragments of former habitat. LÄS MER

3. 2. The role of regeneration in plant niche differentiation and habitat specialization

   Författare :Dirk-Jan ten Brink; Biologiska institutionen; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; seed mass; seed size; drought; shade; seed germination; seed dormancy; seedling establishment; plant community ecology; assembly rules; habitat specialization; plant recruitment; Regeneration; niche differentiation; phylogenetic independent contrasts; plant traits; soil fertility; comparative ecology;

   Sammanfattning : To predict the effects of environmental change and nature management on the distribution of plant species, it is crucial to understand the mechanisms of plant niche differentiation and habitat specialization. The importance to habitat specialization of particular plant traits and requirement of the regenerative phase of the plants life has received scanty interest. LÄS MER

4. 3. Effects of seed size and habitat on recruitment patterns in grassland and forest plants

   Författare :Karin Lönnberg; Ove Eriksson; Per Milberg; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Seed size; seedling establishment; seedling survival; recruitment; seed removal; co-existence; game-theory; Plant Ecology; växtekologi;

   Sammanfattning : A trade-off between seed size and seed number is central in seed ecology, and has been suggested to be related to a trade-off between competition and colonization, as well as to a trade-off between stress tolerance and fecundity. Large seeds endure hazards during establishment, such as shading, drought, litter coverage and competition from other plants, better than do small seeds, due to a larger amount of stored resources in the seed. LÄS MER

5. 4. On the Ecology and Evolution of seed and Bud Dormancy

   Författare :Patric Nilsson; Biologiska institutionen; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; bet-hedging; overcompensation; herbivory; plant compensatory growth; bud dormancy; endosperm; seed provisioning; Seed dormancy; parent-offspring conflicts; Ecology; Ekologi; Botany; Botanik;

   Sammanfattning : This thesis considers the ecological and evolutionary significance of seed and bud dormancy. First, I present theoretical support to the idea that seed dormancy may evolve as a strategy to reduce sib competition in temporally homogeneous environments. LÄS MER

7. 5. Colonisation and extinction of vascular plants on islands off the Swedish east coast

   Författare :Anders Löfgren; Lars Ericson; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; plants; ecological succession; colonizing ability; population dynamics; grasslands; islands; Sweden; plant ecology; Plant Ecology; växtekologi;

   Sammanfattning : Persistence of species is a function of colonisation and extinction among patches at a regional scale. A decrease in area and an increased isolation of suitable patches may result in a decreased colonisation rate and an increased extinction rate among species. LÄS MER