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Our research activities

Local to meso-scale process-oriented studies

In the field:

Our field studies (commenced in 2001) are primarily conducted in a system of altitudinal gradients and a separate system of island-main transect pairs. Altitudinal gradients are valuable as a a proxy for natural climatic variation in studies of life history responses in insects. The island-mainland transects pairs are specifically designed to elucidate the importance of dispersal versus climate for moth population fluctuations. We focus on the following:

  • Host-parasitoid dynamics in altitudinal gradients
  • Phenological development and timing in moth, birch and parasitoids
  • The role of climate and dispersal on local spatial dynamics
  • Local spatial synchrony and travelling waves
  • Dispersal and local recruitment in altitudinal gradients (to begin in 2008)
  • The ecology and dynamics of an invasive moth species, A. aurantiaria

In the laboratory:

The timing of larval emergence from the eggs in relation to the timing of budburst in the host tree is a critical stage in the life cycle of birch forest moth and hence for the development of population outbreaks. The process is temperature dependent. In addition to tailored field studies of larval and birch phenology, we are currently initiating a study of developmental rates of moth larvae and parasitoids under controlled temperature regimes in the laboratory. We will focus on the following:

  • Developing species specific models for the temperature-dependent development (in particular timing of egg hatch) of each moth species

  • The relationship between parasitoid and moth phenology (match/mismatch) under different temperature scenarios (in particular the observed increasingly earlier spring)
  • The relationship between birch and moth phenology (match/mismatch) under different temperature scenarios (in particular earlier spring)

Large-scale spatial dynamics and pattern analyses

Moth population data are tediously sampled in the field. Ground measures cannot be obtained for large geographical regions. Fortunately, several aspects of the birch forest-moth system makes it suitable for remote sensing approaches: i) severe outbreaks result in (near-)complete defoliation, possibly forest death, which can be observed both from airplane and from satellite, ii) the phenogical stage in birch development that is most important for larval development is the timing of bud burst. This can be determined from satellite. In 2006, we initiated remote sensing studies in order to obtain large-scale information on the distribution, extent and temporal dynamics of severe moth outbreaks. From 2008 this will be extended by parallell ground and satellite studies of birch forest phenology. In addition we analyse regional patterns of spatio-temporal outbreak dynamics using historical outbreak records. We focus on the following:

  • Use of remote sensing vegetation indices to identify moth outbreak areas.
  • Surveillance of birch forest phenology (in particular timing of bud burst): from field measures to satellite imagery (to begin in 2008)
  • The relationship between large-scale variation in phenological dates and the distribution of moth outbreaks (to begin in 2009/2010)
  • Aerial surveys of outbreak areas in Troms county.
  • Spatial dynamics and pattern analyses of historical outbreak records.