Field Inventory to Determine Effects of Military Disturbance on Biodiversity at the Landscape Level at Grafenwöhr Training Area, Germany
One of the most fundamental questions in ecology or in the field of ecosystem or land management is, “How many species are present?” The total number of species in a given area, community or landscape is known as the species richness. As early as the 1920’s, attempts to estimate species richness were based on species-area relationships which suggest that the number of species increases as the size of the area increases. While conceptually accurate, the relationship implies that two areas of equal size should support approximately an equivalent number of species. That is seldom the case. The concept fails to explicitly account for habitat heterogeneity or other factors that contribute to the ability of an area to support varying numbers of species. Although habitat heterogeneity is at least indirectly linked to area size, contemporary ecological thought suggests that habitat heterogeneity, rather than area size, is the driving force for species richness. It has long been accepted that heterogeneous habitats tend to support a greater diversity of species because of the increased number of ecological niches present.
Topography and soils, as well as habitat disturbance are primary contributors to habitat heterogeneity. The Intermediate Disturbance Hypothesis was first proposed to explain the link between disturbance and habitat heterogeneity. It predicts maximum biodiversity at intermediate levels of disturbance which avoid competitive exclusion by dominant species occurring at low levels of disturbance, and also preventing the creation of highly disturbed environments that are only suitable to disturbance tolerant species. The Heterogeneous Disturbance Hypothesis, suggests that irregularity of disturbance creates numerous niches where multiple species with varying ecological requirements may successfully coexist in close proximity.
This 3-phase project has been conducted at Grafenwöhr Training Area (GTA), Germany to determine the effects of military disturbances on biodiversity at the landscape level. Phase I measured habitat heterogeneity (the number of disturbance types present in a given area and the number of habitat patches created by the disturbances) and related it quantitatively to plant biodiversity. Phase II examined the relationship between habitat heterogeneity and the spectral heterogeneity of satellite imagery. In Phase II we also investigated the link between spectral heterogeneity and plant species richness, the simplest measure of plant biodiversity. Phase III, currently near completion, evaluates the use of satellite imagery to estimate more complex measures of plant biodiversity.
GSD Principal Investigators
|Warren, Steven D||Disturbance Ecologist||801-356-5128|
Cooperators and Sponsors
Anke Jentsch, University of Bayreuth
Keith Olson, Colorado State University
U.S. Army, Europe