Webpages tagged with «OTC»
World-wide observations of current climate change, such as increased temperature and severe rain events and droughts are caused by release of CO2 by human activities using fossil fuels and by biogeochemical feed-back mechanisms (Solomon et al. 2007, Wesssel et al. 2004, Melillo et al. 2011). Such changes may disrupt the functioning of terrestrial ecosystems on our planet, which are vulnerable to disturbance (Millennium Ecosystem Assessment 2005, Elmendorf 2012).
A climate change experiment with open top chambers (OTCs) was established in the Dryas octopetala heath on Sanddalsnuten in 2000. Combined warming and nutrient addition has increased productivity and grass dominance at the cost of mosses, lichens, and small herbs, resulting in decreased diversity. In a seed sowing experiment we examined the relative role of dispersal and local interactions for alpine plant community diversity under climate warming. The long term effects of warming and local interactions on species recruitment and community dynamics will be examined in the coming years. This project is part of the International Tundra Experiment (ITEX).
Dividing available resources between reproduction and different somatic processes in organisms is associated to trade-offs in each species life-history. The variability in cost responses in plants has been discussed upon the variability in environmental conditions. We established a field experiment at Sanddalsnuten with the alpine herb, Parnassia palustris L. in focus. The reproductive level was artificially manipulated to determine if there exists cost of reproduction in this species. The field experiments involved manipulations of temperature regime by using open top chambers (OTCs) to simulate a warmer climate, and manipulations of current level of reproductive investment by supplemental hand-pollination (increasing output) and bud removal (decreasing output). Growth, survival, and reproduction was then determined the next year and compared inside and outside the OTCs.