Ecosystem Restoration
Why do we need to restore natural resources in National Parks?
Park resources have been degraded through human activities before and after designation as a park unit by congress. Many lands were logged, grazed or mined, leaving a legacy of weedy vegetation and eroded soils. Some park management, such as fire exclusion and emphasis on large mammals to enhance visitor experience, have lead to imbalances in park resources. Park resources also experience continuous threats from alien species, pollution, and climate change.
Restoration at Work: Lands that were added to Big Bend National Park are degraded from intensive land use, leading to loss of native vegetation and over a foot of soil to erosion. NPS must evaluate short-term stabilization as well as conduct studies to decide on the appropriate condition for the site based on the level of degradation, and how to achieve that condition in a cost-effective way.
What is Ecosystem Restoration? Why is this an approach NPS uses
We consider ecosystems broadly as a community of organisms interacting among themselves and with their physical environment; the pattern of an ecosystem is described by its composition (e.g., number and kinds of species) and structure (the relative proportions of the species); the dynamics of an ecosystem are typically described by process rates (e.g.; nutrient cycling) and trophic linkages; the spatial and temporal boundaries of ecosystems are determined by the nature of the investigation-that is, the essential attribute is the "system" that characterizes patterns and dynamics, not the locality; thus, a comprehensive lake-ecosystem study might include the lake itself along with its catchment basin, nutrient-loading for development, and distant transport of pollutant into the lake.
A "boundary" can still conceptually be drawn around the catchment basin. In this way, ecosystems can be considered both spatial (driven by all of the natural phenomena within designated boundaries) and functional (identified by the processes such as fire, or nutrient availability to plants and "outputs" from the system such as the amount of plant material or biomass or sediment from a watershed).
The NPS goal to do ecosystem restoration then, is to not only replace parts of a system, such as grasses that had been removed through grazing, but conditions that support grasses, such as soil organisms, and the processes that regulate grass growth and reproduction, such as the appropriate number of bison and the appropriate frequency of fire. (See Picture on left)