Land Cover / Biodiversity

Earth’s surface is two-thirds water. The continents on which we live make up the remainder. We rely on Earth’s surface to supply most of what we need to live. Therefore, mapping and monitoring this surface is critical to our wise use and protection of it.

Remote sensing from space has the advantage of being able to cover large areas quickly, and to revisit the same area frequently. However, not all of the detail that can be seen at ground level may be detected by a remote sensing system. Therefore it is beneficial to collect data at sample sites on the ground to accompany remotely sensed data about an area.

Remote sensing observations of the land surface are usually presented as digital images. The GLOBE programme uses Landsat Thematic Mapper imagery, which has a pixel size of 30m x 30m, and it senses five different wavelengths of light – blue, green, red, near infrared and two mid-infrared. The satellite images that are produced can then be used to make maps of land cover types.

How good are the land cover maps made from remotely sensed data? The way to answer this question is to conduct an accuracy assessment of the remotely sensed map. If appropriate sample land cover sites are visited on the ground, then these samples can be compared to the same areas on the map and a measure of map accuracy determined.

It is important that the ground samples and the remote sensing maps use the same classification system. A classification system consists of a list of labels or land cover types and the corresponding definitions for each label. GLOBE uses the international MUC system to label sample sites visited on the ground as well as the maps made from the remotely sensed data. As a result, a consistent and uniform land cover map can be created for the entire world and validated.

All living things depend on their land cover for survival. They find shelter, food and protection there. Land cover has a direct effect on the kinds of animals that will likely inhabit an area. Therefore, land cover is of great interest to ecologists, who study how plants and animals relate to their environment. Land cover can also influence weather, soil properties, and water chemistry. Different land cover types are all distinct in their effects on the flow of energy, water and various chemicals between the air and surface soil.

Natural land cover, meaning land cover that is not the result of human activity, is often an indication of the climate of an area. For instance, forests may be found on the wet side of a mountain while in the rain shadow on the other side there may be shrubland. In a coastal region with frequent fog, the plants that grow there modify the soil over time. The land cover in such an area is a community of trees, shrubs, and other plants indicative of a foggy coast. Large rainforests actually create their own weather with daily rain showers. In deserts, plants adapted to dry conditions dominate the land cover. Knowing the type of land cover in a region helps us understand the local climate.

Biometry data collected in the field also assists scientists in monitoring the amount of nutrients, water and gases in vegetation. This is helpful in understanding Earth systems, including; nutrient cycles, the energy cycle and the hydrological cycle. Land cover influences these cycles in a variety of ways.

For more information on GLOBE land cover/biodiversity protocols, please visit the teacher’s guide at the GLOBE website here...

GLOBE PowerPoint Presentations and Data Sheets

These are the PowerPoint (PPT) presentations that have been used in GLOBE workshops. They are useful for helping you to understand the various land cover/biodiversity protocols.

To view further PowerPoint presentations on advanced protocols click here... Further land cover resources can be found in the Resource section of this website.