Stiftelsen Oscar och Lili Lamms Minne
Du är här: Hem // 2009 
TitelLinking aboveground and belowground: how foliar herbivory affects soil oribatid mite communities
NoFO2009-0054
UniversitetSveriges lantbruksuniversitet
InstitutionInstitutionen för Ekologi
HuvudsökandeAstrid Taylor
Beviljat belopp 300 000
Sammanfattning
Ecologists are becoming increasingly aware of the belowground effects of aboveground, foliar herbivory on the structure of decomposer communities and their functions e.g. decomposition and nutrient cycling. However, the underlying mechanisms and the effects on individual groups of soil organism and their interactions are poorly understood. The present project will provide new valuable insight into these belowground effects of herbivory. My objective is to examine how different levels of above-ground herbivory alter the abundance and community structure of oribatid mites along a productivity gradient in a Swedish boreal forest. Due to a number of characteristic features in their live cycle oribatid mites qualify as good indicator organisms of environmental changes and (natural) disturbance. My aim is to relate changes in oribatid mite community structure to different levels of herbivory. Another goal is to link the results of my study with research on other soil organism groups (collaborative research on mycorrhizal fungi and collembolans) that strongly interact with oribatid mites. Investigating foliar herbivory along a productivity gradient will also allow to assess the impact of plant community composition on herbivore effects. The study site is a long-term experiment in northern Sweden where the effect of different intensities of moose browsing on above-ground plant parameters along a forest productivity gradient has been investigated for 10 years. Fenced exclosures were used to simulate 4 intensities of moose browsing at 8 forests sites along the gradient. Simulation will be terminated at the end of 2009, therefore samples for oribatid mite determination need to be taken in autumn 2009. 10 soil samples will be taken randomly at each of the 4 moose density treatments and at 4 sites along the productivity gradient (160 samples in total). Animals will be extracted and stored in alcohol. Processing of the mites will start in January 2010 and will be finished in December 2010. First oribatid mites will be sorted to genus level by a laboratory assistant (six month, working 50%) and will then be identified to species level by A.R. Taylor (three month, working 100%). Studies on belowground effects of herbivory are rare and show highly variable results, strongly depending on the ecosystem studied. With the prospect of profound shifts in the dynamics of Scandinavian forest ecosystems within this century, it is important to improve our understanding of these above-belowground links. The latter is essential in order to predict how herbivory as an external driver of above ground vegetation dynamics will affect i) the diversity of decomposer organisms, and ii) important ecosystem processes like carbon and nutrient sequestration and iii) soil and forest productivity. In order to manage forests as a renewable resource, it is critical to account for these effects when developing wildlife management, forestry and conservation plans for Swedish forests ecosystems.