Five core research themes have been central to LTER Network science from the conception of the Network. Research in these core areas requires the involvement of many scientific disciplines, over long time spans and broad geographic scales. Data on the core areas are collected to establish and understand the existing conditions in an ecosystem before any experimental manipulation is begun.

The common focus on core areas facilitates comparison among and across sites in the Network.

  • Primary Production – Plant growth in most ecosystems forms the base or “primary” component of the food web. The amount and type of plant growth in an ecosystem helps to determine the amount and kind of animals (or “secondary” productivity) that can survive there. Read LTER research stories related to primary production.
  • Population Studies – A population is a group of organisms of the same species. Like canaries in the coal mine, changes in populations of organisms can be important indicators of environmental change. Read LTER research stories related to population studies.
  • Movement of Organic Matter – The entire ecosystem relies on the recycling of organic matter (and the nutrients it contains), including dead plants, animals, and other organisms. Decomposition of organic matter and its movement through the ecosystem is an important component of the food web. Read LTER research stories related to organic matter movement.
  • Movement of Inorganic Matter – Nitrogen, phosphorus, and other mineral nutrients are cycled through the ecosystem by way of decay and disturbances such as fire and flood. In excessive quantities nitrogen and other nutrients can have far-reaching and harmful effects on the environment. Read LTER research stories related to mineral cycling.
  • Disturbance Patterns – Disturbances often shape ecosystems by periodically reorganizing structure, allowing for significant changes in plant and animal populations and communities. Read LTER research stories related to disturbance patterns.

Two additional themes emerged with the addition of urban LTER sites, but it has become clear that they are also relevant for the rest of the Network:

  • Land Use and Land Cover Change: examine the human impact on land use and land-cover change in urban systems and relate these effects to ecosystem dynamics. Read LTER research stories related to land use and land cover change.
  • Human-Environment Interactions: monitor the effects of human-environmental interactions in urban systems, develop appropriate tools (such as GIS) for data collection and analysis of socio-economic and ecosystem data, and develop integrated approaches to linking human and natural systems in an urban ecosystem environment. Read LTER research stories related to human-environment interactions.