Browsing by Subject "lajirunsaus"
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(2010)This thesis studies the tree species’ juvenile diversity in cacao (Theobroma cacao L.) based agroforestry and in primary forest in a natural conservation forest environment of Lore Lindu National Park, Sulawesi, Indonesia. Species’ adult composition in Lore Lindu National Park is relatively well studied, less is known about tree species’ diversity in seedling communities particularly in frequently disturbed cacao agroforestry field environment. Cacao production forms a potentially serious thread for maintaining the conservation areas pristine and forested in Sulawesi. The impacts of cacao production on natural environment are directly linked to the diversity and abundance of shade tree usage. The study aims at comparing differences between cacao agroforestry and natural forest in the surrounding area in their species composition in seedling and sapling size categories. The study was carried out in two parts. Biodiversity inventory of seedlings and saplings was combined with social survey with farmer interviews. Aim of the survey was to gain knowledge of the cacao fields, and farmers’ observations and choices regarding tree species associated with cacao. Data was collected in summer 2008. The assessment of the impact of environmental factors of solar radiation, weeding frequency, cacao tree planting density, distance to forest and distance to main park road, and type of habitat on seedling and sapling compositions was done with Non-metric Multidimensional Scaling (NMS). Outlier analysis was used to assess distorting variables for NMS, and Multi-Response Permutation Procedures (MRPP) analysis to differentiate the impact of categorical variables. Sampling success was estimated with rarefaction curves and jackknife estimate of species richness. In the inventory 135 species of trees and shrubs were found. Only some agroforestry related species were dominating. The most species rich were sapling communities in forest habitat. NMS was showing generally low linear correlation between variation of species composition and environmental variables. Solar radiation was having most significance as explaining variable. The most clearly separated in ordination were cacao and forest habitats. The results of seedling and sapling inventory were only partly coinciding with farmers’ knowledge of the tree species occurring on their fields. More research with frequent assessment of seedling cohorts is needed due to natural variability of cohorts and high mortality rate of seedlings.
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(2016)For the conservation of biodiversity, it is important to examine the factors that shape species richness in different ecosystems. Global warming is predicted to be most pronounced in arctic-alpine areas and arctic environments, especially in major ecotones, like environments close to the tree lines. Therefore by examining the species richness, distribution and requirements of species living in mountainous areas, it is possible to assess the effects of climate change in different spatial scales. Elevational gradients are suitable for this kind of research, because many ecosystems processes and structure of local communities change along elevational gradients. Studies carried out in elevational gradients can help us to find out the mechanisms that shape local communities. The elevational patterns of species richness of micro-organisms like diatoms have been studied increasingly lately, but the results of the factors shaping species richness along elevational gradient are varied between different studies and groups of micro-organisms. Therefore it is important to learn more about the factors that shape species richness of micro-organisms along elevational gradients. In this thesis’s the elevational patterns of species richness and species evenness were studied in three different mountain streams in northern Norway and Kilpisjärvi (n= 44). The study also examines the effects of altitude to taxonomic relatedness of diatom species. Diatom and water chemistry samples were collected in August 2013. Generalized linear models (GLM) were used to analyse species richness and the correlation between environmental variables and species richness were examined with pairwise correlation tests. Taxonomic distinctness was calculated with taxondive-command. According to the GLM, the species richness was best explained (49,2 %) by pH of stream water, stream depth, conductivity and altitude. Species evenness was best explained (45,6 %) by water temperature and total nitrogen (TN). Altitude showed a statistically significant relation to species richness (p= 0,003) and species evenness only in Lepänjoki (p< 5,45e+07). Species were not phylogenetically more clustered as elevation increased. Altitude did not explain the taxonomic distinctness of diatom species in the research streams. It can be concluded that a deeper riverbed guarantee more stable conditions to diatom species. Similarly, higher water pH value is more favorable habitat for diatoms, than acidic waters. Altitude may affect species richness through bedrock geology, which probably affects pH value and conductivity in the research streams. The short elevational gradients probably affect the fact that species richness did not decrease as altitude increased and that the species were not closely related to each other at the upper end of the gradient.
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