Sökning: "seedling survival"
Visar resultat 1 - 5 av 21 avhandlingar innehållade orden seedling survival.
1. Effects of seed size and habitat on recruitment patterns in grassland and forest plants
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
2. Plant Population Dynamics of Dodonaea angustifolia and Olea europaea ssp. cuspidata in Dry Afromontane Forests of Ethiopia
Sammanfattning : Human disturbance has led to excessive deforestation and to a very limited forest cover in the Afromontane zone of Ethiopia, which forms a large part of the country. Thus urgent conservation measures are required to ameliorate the situation. LÄS MER
3. Reproductive patterns of birches (Betula spp.) in northern Sweden
Sammanfattning : The aim of this thesis was to study patterns of reproduction of Betula pendula and B. pubescens coll. along an altitudinal, coastal-inland, gradient in northern Sweden. The altitudinal variation was related to the distribution of the birch taxa along the gradient. LÄS MER
4. Mosses as mediators of climate change : implications for tree seedling establishment in the tundra
Sammanfattning : Alpine and arctic tree line expansion depends on the establishment of tree seedlings above the current tree line, which is expected to occur with climate warming. However, tree lines often fail to respond to higher temperatures. Other environmental factors are therefore likely important for tree seedling establishment. LÄS MER
5. Consequences of bushmeat hunting in tropical forests
Sammanfattning : This thesis evaluates the effect of bushmeat hunting in southeastern Nigerian rainforests on: 1) adult tree, seedling, and animal community compositions 2) germination and survival among seedlings in association with competition 3) changes in community composition at multiple trophic levels 4) leaf nitrogen concentration (LNC), leaf mass per area (LMA) and stem specific density (SSD) 5) on human reliance on forest resources and rural people use forest resources. Data for the first four evaluations were obtained from surveys, manipulative experiments in seedling plots and collected leaf samples in three pairs of sites with high (hunted sites) and low (protected sites) hunting pressure but with similar adult tree composition. LÄS MER
