The Long Term Ecological Research (LTER) Network consists of a group of over 1800 scientists and students studying ecological processes

Ecology

Ecology is the scientific study of the relations that living organisms have with respect to each other and their natural environment. Variables of interest to ecologists include the composition, distribution, amount , number, and changing states of organisms within and among ecosystems...

 over extended temporal and spatial scales. 26 LTER sites cover a diverse set of ecosystem

Ecosystem

An ecosystem is a biological environment consisting of all the organisms living in a particular area, as well as all the nonliving , physical components of the environment with which the organisms interact, such as air, soil, water and sunlight....

s.

LTER sites

There are 26 field sites within the LTER Network across the USA, Puerto Rico

Puerto Rico

Puerto Rico , officially the Commonwealth of Puerto Rico , is an unincorporated territory of the United States, located in the northeastern Caribbean, east of the Dominican Republic and west of both the United States Virgin Islands and the British Virgin Islands.Puerto Rico comprises an...

, and Antarctica, each providing facilitating research on different ecosystems. Here's the list with active links.

• Andrews LTER (AND) external link
• Arctic LTER (ARC) external link
• Baltimore Ecosystem Study (BES) external link
• Bonanza Creek LTER (BNZ) external link
• Central Arizona - Phoenix (CAP) external link
• California Current Ecosystem (CCE)external link
• Cedar Creek Ecosystem Science Reserve
  Cedar Creek Ecosystem Science Reserve
  The Cedar Creek Ecosystem Science Reserve is an ecological research site located primarily in East Bethel, Minnesota in the counties of Anoka and Isanti on the northern edge of the Minneapolis-Saint Paul metropolitan area...
  
   (CDR) external link
• Coweeta LTER (CWT) external link
• Ducke Adolfo Ducke Forest Reserve
  Ducke Adolfo Ducke Forest Reserve
  Adolfo Ducke Forest Reserve is 10,000 ha protected area on the outskirts of Manaus, Brazil. It is a member of the Long Term Ecological Research Network. The reserve sits at the intersection of two major drainage areas, the Amazon River and the Rio Negro...
  
  
• Florida Coastal Everglades (FCE) external link
• Georgia Coastal Ecosystems (GCE) external link
• Harvard Forest
  Harvard Forest
  Harvard Forest is an ecological research area of owned and managed by Harvard University and located in Petersham, Massachusetts. The property, in operation since 1907, includes one of North America's oldest managed forests, educational and research facilities, a museum, and recreation trails...
  
   (HFR) external link
• Hubbard Brook LTER (HBR) external link
• Jornada Basin LTER
  Jornada Basin LTER
  Jornada Basin Long Term Ecological Research program, in collaboration with the USDA ARS Jornada Experimental Range, studies the causes and consequences of desertification...
  
   (JRN) external link
• Kellogg Biological Station
  Kellogg Biological Station
  Kellogg Biological Station , Michigan State University's largest off-campus education complex, is located in Hickory Corners, Michigan . Many of the facilities there were originally built by Will Keith Kellogg of Kellogg's cereal, after whom the station is named...
  
   (KBS) external link
• Konza Prairie
  Konza Prairie
  The Konza Prairie Biological Station is a 3,487-hectare preserve of native tallgrass prairie in the Flint Hills of northeastern Kansas. It is located south of Manhattan, Kansas and its southern boundary parallels Interstate 70...
  
   (KNZ) external link
• Luquillo LTER (LUQ) external link
• McMurdo Dry Valleys (MCM) external link
• Moorea Coral Reef (MCR) external link
• Niwot Ridge LTER (NWT) external link
• North Temperate Lakes (NTL) external link
• Palmer Station
  Palmer Station
  Palmer Station, on Anvers Island, is Antarctica's only US station north of the Antarctic Circle. Initial construction of the station finished in 1968. The station, like the other US Antarctic stations, is operated by the United States Antarctic Program....
  
   Antarctica (PAL) external link
• Plum Island Ecosystem (PIE) external link
• Santa Barbara Coastal (SBC) external link
• Sevilleta LTER (SEV) external link
• Shortgrass Steppe (SGS) external link
• Virginia Coast Reserve Long-Term Ecological Research
  Virginia Coast Reserve Long-Term Ecological Research
  The Virginia Coast Reserve Long-Term Ecological Research project is funded by the National Science Foundation. The VCR/LTER project's research activities focus on the mosaic of transitions and steady-state systems that comprise the barrier-island/lagoon/mainland landscape of the Eastern Shore of...
  
  (VCR) external link