Tadpoles are known to behaviorally respond to visual, auditory or chemical cues. I examined the influence of group size and light conditions on the activity of Phyllobates vittatus. I performed laboratory experiments to measure locomotor activity. Activity levels of tadpoles were higher in the groups. Light conditions did not influence activity level of tadpoles. My results suggest that the group size is one of the main factors influencing tadpole locomotor activity of Phyllobates vittatus.

Med den tekniska utvecklingen inom 3D-skanning det senaste decenniet har användningen av punkmolnsdata ökat signifikant. För att skapa dessa punkmoln används en mängd olika metoder och instrument. Bland annat används ofta fotogrammetri, terrester laserskanning eller mobil laserskanning. Med de nyare mobila skannrarna används oftast en SLAM-algoritm för att kunna korrekt skanna omgivningen samtidigt som skannern förflyttas. Till detta används oftast en IMU som positionerar skannern genom tröghetsnavigering eller kameror för att med triangulering bestämma positionen. Med nya förbättrade algoritmer och utrustning blir systemen hela tiden noggrannare och det utvecklas fler och fler nya system, ofta för specifika användningsområden. Matterport Pro2 3D-kamera som testades i detta projekt är ett sådant system som huvudsakligen utvecklats för att genom skanning, RGB-D och 360°- bilder visualisera och skapa digitala modeller av bostäder. Dessa modeller skapas både i form av punktmoln och meshmodeller. I projektet undersöks hur olika ljusförhållanden påverkar resultatet vid skapande av 3D-modeller med Matterport Pro2 kameran. Uppmätta längder mellan signaler utplacerade i testrummet användes för att kontrollera punktmolnen. Totalt skannades rummet fem gånger vid olika ljussättning varierande från 1 till 800 lux. Avvikelserna i längderna från punktmolnen jämfördes för att avgöra vilket punktmoln som avvek minst från de uppmätta längderna i rummet. Resultatet tyder på att bästa ljussättningen är runt 30 - 60 lux. Ingen skillnad i mätosäkerhet mellan övriga ljusnivåer kunde ses. Utöver det visar avvikelserna också tecken på påtagliga systematiskt fel vilket inte är helt oväntat och har påvisats av en tidigare studie av samma kamera. Detta betyder att kameran behöver kalibreras innan den används för skanning som kräver låg mätosäkerhet. / Due to the technological development within 3D-scanning the last decade usage of pointcloud data has increased significantly. To generate these pointclouds a plethora of methods and instrument are used. Among other photogrammetry, terrestrial laser scanning and mobile laser scanning are commonly used. With the newer mobile scanning systems a SLAM algorithm is usually used for the scanner to correctly scan the surroundings while being moved at the same time. To achieve this a IMU is usually used for positioning or cameras using triangulation. With new algorithms and equipment scanning systems keeps improving. This leads to more and more systems being developed, usually for a specific area of usage. Matterport Pro2 3D-camera which was tested in this project is such a system developed mainly for visualising and creating 3D-models of housing through scanning, RGB-D and 360°-images. These models generated are pointclouds aswell as meshmodels. In this project the effect of different illuminance has on the results when creating 3D-models with the Pro2 camera is tested. Measured distances between targets placed around the testing room were used for checking the point clouds for errors. In total five scans were performed at different illuminance varying from 1 – 800 lux. Deviations between measured distances and point cloud distances were compared to determine which point cloud deviated the least. Results show that an illuminance of about 30 - 60 lux gave the best result. Any significant differences between the other light conditions could not be determined. Furthermore, the results imply there is a systematic error which is not completely unexpected and has been shown in a previous study with the same camera. This means the camera needs a calibration before being used to scan where higher accuracy is needed.

In the wetter climates associated with the coastal forests of northwestern North America, coarse woody debris (CWD) accumulations in the form of snags, downed boles, and large branches can be large in natural forest ecosystems. Seedlings often regenerate on stumps and downed logs in the understory of old-growth coastal forests. The question remains though, whether CWD is a necessary component for seedling survival and growth in forests managed for commodity production. This study addresses one concern of forest managers: is there an immediate nutritional or moisture supply advantage conferred by CWD for the survival and growth of seedlings in the coastal climate of British Columbia? We compared survival and growth of seedlings planted in decaying wood compared to non-woody humus forms and mineral soil under heavy shade and full light conditions. Low light environments are of particular interest since reports of the strong association between CWD and regeneration has primarily referred to understory seedlings and saplings in old-growth forests.

Mountain forests are an important part of the landscape in our country. In the last three decades they have been seriously damaged by anthropogenic influence, especially immissions. The immissions make worse the health status of Norway spruce (Picea abies) forests, which cause changes in a structure of herbaceous layer, in which the health status of forest stand is reflected. The main goals of my work were to map the cover of herbaceous and mossy layers in two permanent research plots in the Giant Mountains ( Alžbětinka, Modrý důl), to create maps of herbaceous cover, to digitize them and to compare these maps with the extent in years 1993-1994 using a developing analysis in GIS and to detect influence of light conditions on herbaceous layer. Using digitizing and static evaluation of prepared detailed vegetation maps of the both permanent research plots, some important changes were found out in dominant soil cover categories. In the first research plot Alžbětinka, decline of the grass Calamagrostis villosa and increasing of Vaccinium myrtillus cover were evident. In the second research plot Modrý důl, decline of both investigated species, Avenella flexuosa and Calamagrostis villosa, was observed. Another goal of my research was to detect influence of the light conditions on herbaceous layer and nature regeneration of the Norway spruce on permanent research plot Modrý důl. Dependence of the basic categories of the soil cover on the percentual ratio of the light gaps in the crown canopy was proved. Dependence of the height of the seedlings on the ratio of the light gaps was also tested but it was not statistically proved. The negative dependence of survival on the ratio of the light gaps of the seedlings germinated in 1996 was proved, but not of the seedlings germinated in 2004.

Evacuation of trains in tunnels is currently taking place in diverse ways. One of the methods implies that passengers leave the train along the railways on elevated walkways. The knowledge about the impact of elevated walkways on the safety level is today very limited. As more and more elevated walkways are designed in rail tunnels, it is important that studies and evacuation trials are made to investigate how those affect the safety level of the evacuation. This master thesis’ project aims to investigate the relationship between low light conditions, people's behaviour and ability to evacuate a train on an elevated walkway. To investigate this, the core in the work consisted a practical evacuation trial which purpose was to study people’s movement on a raised walkway under different illumination levels: 200 lux, 5 lux and 1 lux. A total of 16 escape trials were performed as controlled evacuations on a simulated elevated walkway with the measures 1.2x20 meters with a level difference down to the ground plane of 1.24 meters. The result of the evacuation trial showed that the intensity of illumination played a significant role in both the movement speed, the person flow and the peoples distance to the edge. The peoples flow and speed did generally decrease during the partial trials performed during the weaker light intensities, 5 lux and 1 lux, compared to partial trials performed during 200 lux. A general result regarding the effect of light intensity on the people’s distance to the edge is that during the partial trials performed with the weaker light intensities, 5 lux and 1 lux, more people chose to go further from the edge. The conclusion of these results is that a minimum brightness in tunnels should be 1 lux, but a stronger illumination should be sought to increase the safety of the passengers in case of evacuation. Regarding the learning effect on the trial procedure, it can be seen from the results that the more trials carried out, the closer the edge the people went combined with an increased speed and flow. The people became comfortable in the environment and hesitated less, which generated a source of error in the result. A conclusion of the practical evacuation trial is that by conducting a trial in this type of environment, we were given the opportunity to study the problems as well as the complexity that an evacuation may imply. The experiment further provided valuable information and knowledge about the problems that may arise in an evacuation, both from a technical and behavioural perspective.

Light is essential component of forest ecosystem, as limited light availability in forest-floor restricts herb and tree seedlings growth. Importance of light availability for maintaining plant species diversity and community structure wasn't sufficiently evaluated in the Czech Republic. This study focus on the ecological relevance of light availability on both landscape and local scale. Relationship of light to cover, diversity and species composition was quantified in the thesis. Dominant tree species affected light availability and its spatial variability. Light availability was along the soil reaction and slope most influential factor for large-scale species diversity. Within-site light variability affected plant diversity more than soil reaction variability. Measuring light by means of hemispherical photography seems to be an appropriate for studies like this. Light availability influnence on community compostition is weak in comparison with other environmental gradients.