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 U.S. and Mexican LTER Networks are cooperating in the development of a new network of hurricane researchers.
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.
The Virginia Coast Reserve (VCR) is an extremely dynamic, heterogeneous coastal barrier landscape comprising mainland watersheds, tidal marshes, lagoons, and barrier islands. Our goal for the VCR LTER program is to develop a predictive understanding of the response of coastal barrier systems to long-term environmental changes in climate, sea level and land use, and to relate these to the ecological services the coastal barrier systems provide.
Despite substantial changes in climate, sea-ice and glacier extent, and vegetation in much of the Arctic, the area near Toolik Lake, Alaska has experienced no significant trends of increasing temperature, altered precipitation, or increasing active-layer thaw depth. There has been, however, a near doubling of alkalinity in Toolik Lake since 1975 and increases in alkalinity in many lakes of all depths and sizes in the surrounding area. Lake monitoring indicates that in-lake processes such as sulfate or nitrate reduction cannot account for these alkalinity increases.
Interactions between hurricanes and the legacy of human disturbance, determine the future composition of the Luquillo Forest.
The Luquillo Forest Dynamics Plot (LFDP) is a 16-ha long-term study plot in subtropical wet forest in the Luquillo Mountains of Puerto Rico. It is part of the Luquillo LTER and the Center for Tropical Science (CTFS) network of large tropical forest plots. Forests are often subject to multiple, compounded disturbances, representing both natural and human-induced processes. Our goal is to understand forest structure, diversity and dynamics, and to predict long-term changes resulting from interactions of past human land use and intermittent hurricane damage.
Impacts of increasing woody vegetation in herbaceous dominated systems: Understanding the role of fire.
Increased woody plant cover in grasslands is a global phenomenon and a critical threat to conservation of grasslands and their biodiversity. Changes in land management, such as reduced fire frequency, can increase woody plant abundance, while other factors such as increased CO2 concentration, N deposition, and habitat fragmentation might be contributing factors.
The temperate forests of eastern North America support high biodiversity and critical ecosystem functions while providing natural resources and cultural benefits to an expanding human population. The region is shaped by a legacy of landscape change: major shifts in climate, vegetation and disturbance at millennial time scales; extensive deforestation for agriculture in the 17th – 19th centuries; and abandonment of farmlands, natural reforestation and increasing urbanization through the mid-21st century.
An ongoing field experiment to test if zonation of tidal marsh vegetation is in synchrony with hydrologic conditions developed during rising sea level
A field experiment has been initiated in August 2008 to determine if the vegetation of a coastal marsh is in synchrony with hydrologic conditions that have developed with rising sea-level. The hypothesis being tested is that plant community structure will persist in existing zones of vegetation in the face of sea-level rise unless disturbance provides opportunities for species change under more frequent tidal inundation.