Landscape Development Intensity Index

Abstract

The condition of landscapes and the ecological communities within them is strongly related to levels of human activity. Human-dominated land uses and especially the intensity of the uses can affect adjacent ecological communities through direct, secondary, and cumulative impacts. Using land use data and a development-intensity measure derived from energy use per unit area, an index of Landscape Development Intensity (LDI) can be calculated for watersheds of varying sizes to estimate the potential impacts from human-dominated activities that are experienced by ecological systems within those watersheds. The intended use of the LDI is as an index of the human disturbance gradient (the level of human induced impacts on the biological, chemical, and physical processes of surrounding lands or waters). The LDI can be used at the scale of river, stream, or lake watersheds or at the smaller scale of individual isolated wetland watersheds. Based on land uses and land cover, the LDI can be applied using available GIS land use/land cover data, aerial photographs, or field surveys. A description of data needs and methods for calculating an LDI index and several applications of the index as a land use based ranking scheme of the human disturbance gradient for watersheds are given.

Linking landscape development intensity within watersheds to methyl-mercury accumulation in river sediments

“…We investigate the relationship between land-use type and Hg transformation/accumulation in sediment at a watershed scale by use of the landscape development intensity (LDI) index (Brown and Vivas 2005), and Hg data obtained from sediment samples collected from sites with well-identified dominant land use and land cover (LULC). This paper is written primarily to stimulate discussion and research focusing on land use, land-use change over time, and their long-term effects on environmental Hg cycling.…”

“…The intensity of human-dominated land use in landscapes affects ecological processes in natural systems and could be a suitable metric for the disturbance gradient that results from increasing human use of landscapes (Brown and Vivas 2005). Using LULC data and a development intensity measure derived from energy use per unit area, the LDI index was calculated as proposed by Brown and Vivas (2005) and shown in Eq.…”

“…Using LULC data and a development intensity measure derived from energy use per unit area, the LDI index was calculated as proposed by Brown and Vivas (2005) and shown in Eq. 1.…”

“…In this case, the value is a unit of solar emergy expressed in solar emjoules, which is abbreviated sej. When expressed in units of sej ha -l year -l , the emergy use per area per time is referred to as empower density and is calculated as average values for the different defined land-use categories (Brown and Vivas 2005). Finally, the LDI index is obtained as the normalized value of the natural log of the empower density on a scale of 1-10.…”

“…LDI index values between 1 and 2 correspond to sub-basins that are nearly 100 % natural (e.g., open water bodies, natural forests, etc.). LDIs of 2-5 are representative of sub-basins that are dominated primarily by agriculture; and LDIs [5 indicate mining, industrial, and urban land uses (Brown and Vivas 2005). Table 1 gives the non-renewable empower densities obtained from Brown and Vivas (2005) and used to calculate LDI indexes for the various land-use types relevant to this study.…”