Long-Term Ecosystem Research (LTER) is an essential contribution to world-wide efforts to better understand ecosystems. Through research and observation, LTER seeks to improve our knowledge of the structure and functions of ecosystems and their long-term response to environmental, societal and economic drivers. 

Putting something like LTER, with its enormous scope, into practice requires time and the constructive interplay of important building blocks. These comprise the involved research communities, properly equipped and operated research sites in the field, and institutions operating these sites in the long term. Such continuous operation requires appropriate funding schemes across all organisational levels, from sites to countries, and at regional, continental and global scales. 

LTER began in many places around the globe as research initiatives, driven by teams investigating ecosystem functioning at sites operated over long timeframes. What started bottom-up in a highly distributed manner, has evolved into a complex process of organising related communities, projects, services and research sites. Sites striving to operate in the long term and in a sustainable manner (beyond the short-term project lifecycle) have impacted the formation of institutional, national and global science and research infrastructure agendas. The components of the European LTER process reflect this development:

(1) The community and bottom-up networks in LTER-Europe.
(2) A series of eLTER projects: currently eLTER PPP and eLTER PLUS (both EC Horizon 2020, run-time 2020-2026), and eLTER EnRich (EC Horizon Europe, run-time 2024 - 2027).
(3) The emerging formal eLTER Research Infrastructure.

Hint concerning our branding: We distinguish (1) the broader community and networking activities (LTER) from activities related to (2) concrete projects and (3) infrastructure development (eLTER).