The effects of catchment and riparian forest quality on stream environmental conditions across a tropical rainforest and oil palm landscape in Malaysian Borneo

Freshwaters provide valuable habitat and important ecosystem services, but are threatened worldwide by habitat loss and degradation. In Southeast Asia, rainforest streams are particularly threatened by logging and conversion to oil palm, but we lack information on the impacts of this on freshwater environmental conditions, and the relative importance of catchment versus riparian-scale disturbance. We studied sixteen streams in Sabah, Borneo, including old growth forest, logged forest, and oil palm sites. We assessed forest quality in riparian zones and across the whole catchment, and compared it with stream environmental conditions including water quality, structural complexity and organic inputs. We found that streams with the highest riparian forest quality were nearly 4 °C cooler, over 20 cm deeper, had over 40% less sand, greater canopy cover, more stored leaf litter and wider channels than oil palm streams with the lowest riparian forest quality. Other variables were significantly related to catchment-scale forest quality, with streams in the highest quality forest catchments having 40% more bedrock and 20 times more dead wood, along with higher phosphorus, and lower nitrate-N levels compared to streams with the lowest catchment-scale forest quality. Although riparian buffer strips went some way to protecting waterways, they did not maintain fully forest-like stream conditions. In addition, logged forest streams still showed signs of disturbance 10-15 years after selective logging. Our results suggest that maintenance and restoration of buffer strips can help to protect healthy freshwater ecosystems, but logging practices and catchment-scale forest management also need to be considered.During this work SHL was funded by a Natural Environment Research Council (NERC) studentship (number 1122589), Proforest, the Varley Gradwell Travelling Fellowship, Tim Whitmore Fund, Panton Trust and the Cambridge University Commonwealth Fund. MP and RME were supported by European Research Council Project number 281986. HB was funded by the S.T. Lee Fund

Mahdottoman geometrian havainnollistaminen 3d-animaatioilla

TIIVISTELMÄ Opinnäytetyön aiheena on Amos Andersonin taidemuseolle M.C. Escherin näyttelyä varten parityönä tehdyt 3d-mallit, sekä niitä varten tehty tausta tutkimus mahdottomista kuvista. Animaatioiden tarkoituksena oli havainnollistaa 3d-mallinnuksin Escherin töissä esiintyviä kuvia mahdottomista kappaleista. Kirjallisessa osiossa on tutkittu kuvien ja näkemisen teori-aa sekä erilaisia tapoja epätodellisten muotojen esittämiseen. Ne on jaettu yhdestä pisteestä näkemiseen, perspektiivikonstruktioihin ja minimaalipintoihin. Työssä selvisi, mihin kuvien illuusiot perustuvat ja, että 3d-grafiikan avulla voidaan luoda havainnollisia malleja vaikeaselkoisista kuvista. Opinnäytetyön liitteenä on valmiit animaatiot sisältävä cd-levy.The subject of this thesis was to create animations of impossible objects made for a M.C. Escher exhibition at Amos Anderson art museum in Helsinki and to do research on this subject. The modeling was done as a pair work with another student. The goal was to produce clarifying 3d-visualizations of impossible objects used by Escher in his artwork. The written part of the thesis deals with theories of perceiving images and different methods to present impossible forms, such as single point perception, perspective constructions and minimal surfaces. The work explains also how people usually react on these kinds of pictures and why. Working with this subject made me aware of different possibilities of 3d-animation as a tool to create depictive graphic models of obscure pictures and what these illusions are based on. A compact disc with all the animations is included in this thesis