Long-Term Trends in Spatial Partitioning of Biodiversity: Considerations of Disturbance and Recovery
Patterns of biodiversity at large spatial scales (i.e., γ diversity) can be driven by either within-community (α) or among-community (β) components. The degree to which α or β components contribute to γ diversity may depend on the amount of environmental variation that exists in the spatial extents studied. However, few studies have assessed both spatial configuration and temporal changes in biodiversity, especially in systems that frequently experience large-scale disturbance.
The Niwot Ridge (NWT) LTER site was one of the five original LTER sites established in 1980. The LTER program is based at the University of Colorado-Boulder and is administered through the Institute of Arctic and Alpine Research (INSTAAR) and in cooperation with the Mountain Research Station, with special use permits from the US Forest Service.
The U.S. and Mexican LTER Networks are cooperating in the development of a new network of hurricane researchers.
The California Current System is a coastal upwelling biome, as found along the eastern margins of all major ocean basins. These are among the more productive ecosystems in the world ocean. The California Current Ecosystem (CCE) LTER site (centered on 32.9° N, 120.3° W) is investigating nonlinear transitions in the California Current coastal pelagic ecosystem, with particular attention to long-term forcing by a secular warming trend, multi-decadal oscillations (e.g., PDO and NPGO), and ENSO in altering the structure and dynamics of the pelagic ecosystem.
Resilience in a coral reef ecosystem: Initiation of a long-term experiment to determine the effects of multiple disturbances
Documenting the trajectories of ecological communities following a disturbance represents one of the five core research themes central to LTER network science. Quantifying degrees of resilience, here defined as the time needed for a community to return to a previous steady or quasi-steady state following a disturbance, can be especially challenging when ecosystems experience multiple perturbations that, in combination, can cause complex, non-linear community responses.
During May and June of 2006, the LTER CCE program launched a cruise off Point Conception closely following the California Cooperative Oceanic Fisheries Investigations (CalCOFI) line 80 and a valuable dataset was collected. These ocean variables include along-flow and cross-flow spatial gradients, vertical current shear, CTD and iron limitation.
Effects of forest die-back on soil biological and chemical characteristics of a Colorado Lodgepole pine forest
A forest die-back caused by a beetle outbreak on lodgepole and limber pine was used to assess the relative importance of root inputs to the soil food web and chemistry of soils in the Colorado Front Range. We measured a suite of biological and chemical parameters at six sites containing both live and dead trees. We found an increase in amounts of soil inorganic N, decreased soil lable C, and thus a decreased soil labile C:N ratio.
We are investigating the feasibility of employing thermal manipulation, achieved via whole-lake destratification, to extirpate the cold water exotic rainbow smelt (Osmerus mordax) from Crystal Lake, WI. We focus here on the engineering implications of raising the hypolimnion water temperture to exceed the thermal range of the rainbow smelt. An energy balance approach was used to determine the timing and duration of mixing efforts to maximize heat gain and minimize loss to the atmosphere.
The goal of the Arctic LTER is to predict the future ecological characteristics of Arctic Alaska based upon our knowledge of the controls of ecosystem structure and function as exerted by physical setting and geologic factors, climatic factors, biotic factors, and the changes in fluxes of water and materials from land to water.
Urbanization is one of the major threats to stream ecosystems worldwide. The phrase “urban stream syndrome” has been coined to describe patterns in degraded streams draining urban land. In Puerto Rico, urbanization now covers 16% of the island. The fully protected Luquillo Experimental Forest (focus of the LUQ-LTER) is only 23 km from the center of San Juan, a city of 1.3 million. Therefore, LUQ is assessing the impacts of urbanization on tropical stream ecosystem structure and function.