Sökning: "Lars E. Ericson"

Visar resultat 1 - 5 av 7 avhandlingar innehållade orden Lars E. Ericson.

1. 1. Epiphytic lichen responses to nitrogen deposition

   Författare :Otilia Johansson; Kristin Palmqvist; Johan Olofsson; Annika Nordin; Lars E Ericson; Peter Crittenden; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Lichens; air pollution; nitrogen deposition; phosphorus; growth; chlorophyll a; boreal forest; field experiment; irrigation; carbon based secondary compounds; Lavar; luftföroreningar; alg; svamp; kväve; fosfor; skog; Terrestrial ecology; Terrestrisk ekologi; ekologisk botanik; Ecological Botany;

   Sammanfattning : Nitrogen (N) deposition has increased globally over the last 150 years and further increase is predicted for the future. Nitrogen is an important nutrient for lichens, involved in many processes in both photobiont and mycobiont.  However, N can be a stressor, causing many lichens and lichen communities to disappear with increased deposition. LÄS MER

3. 2. Metapopulation and metacommunity processes, dispersal strategies and life-history trade-offs in epiphytes

   Författare :Swantje Löbel; Håkan Rydin; Tord Snäll; Lars E. Ericson; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; asexual; biodiversity; bryophytes; dispersal limitation; establishment; evolution of reproductive traits; germination; growth; habitat fragmentation; landscape dynamics; local processes; patch-tracking; pH; reproduction; species richness; species interactions; Other biology; Övrig biologi; Ecological Botany; Ekologisk botanik;

   Sammanfattning : The aim of this thesis was to increase knowledge about metapopulation and metacommunity processes in patchy, dynamic landscapes, using epiphytic bryophytes as a model system. Host trees and deciduous forest stands in the coniferous landscape are patchy, temporal and undergo changes in habitat quality during succession. LÄS MER

4. 3. Interactions between natural enemies and the dioecious herb Silene dioica

   Författare :Viktoria Pettersson; Barbara E. Giles; Lars Ericson; Pia Mutikainen; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Silene dioica; Delia criniventris; Caryocolum viscariella; Microbotryum violaceum; plant-herbivore interactions; plant -pathogen interactions; sex bias; sex rato; successional gradients; fitness effects; Skeppsvik Archipelago; Terrestrial ecology; Terrestisk ekologi; ekologisk botanik; Ecological Botany;

   Sammanfattning : About 6% of all angiosperms are dioecious. This separation of sexual function to male and female individuals, and the fundamentally different patterns of reproductive resource allocation that follows that separation, are thought to have important ecological and evolutionary consequences for plant enemy interactions. LÄS MER

5. 4. Colonization Patterns of Wood-inhabiting Fungi in Boreal Forest

   Författare :Jörgen Olsson; Lars Ericson; Jørund Rolstad; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Wood-inhabiting fungi; colonization; dispersal; restoration fire; saproxylic beetles; conservation; forest management; boreal forest; Terrestrial ecology; Terrestisk ekologi;

   Sammanfattning : Forest management practices have changed the over-all structure of the Fennoscandian forest landscape resulting in a lack of suitable substrates for many wood-inhabiting species. The objectives of this thesis was to describe the colonization patterns of wood-inhabiting fungi, including the potential role of beetles as dispersal vectors, on different types of dead wood substrate and assess the importance of active measures in the forest landscape in order to restore biodiversity i. LÄS MER

7. 5. Systemic fungal diseases in natural plant populations

   Författare :Anders Wennström; Lars Ericson; Peter G. Ayres; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Systemic diseases; rust; smut; Puccinia minussensis; Lactuca sibirica; Puccinia pulsatillae; Pulsatilla pratensis; lateral growth; abiotic factors; disease transmission; Svampsjukdomar hos växter;

   Sammanfattning : The purpose of this thesis was to study interactions between systemic fungal diseases and perennial plants. Using the systemic rust Puccinia minussensis on the host plant Lactuca sibirica, and the rust Puccinia pulsatillae on the host plant Pulsatilla pratensis, this thesis focused on: (i) the effects of systemic diseases on their hosts (ii) host and pathogen responses to abiotic factors, (iii) the importance of life history strategies for understanding host-pathogen interactions, and (iv) the evolutionary consequences of living in close associations. LÄS MER