SEE-U 2000: Atlantic Forest - Module 9:Exercise 9

Exercise Contents:

• | Your Questions
• | Background
• | Your Assignment
• | Methodology
• | Objectives
• | Key Skills
• | Timetable
• | Materials Needed

Exercise Contents:
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# Atlantic Forest ## Exercise 9: Edge Effects on Selected Aspects of Forest Microclimate Module 9: Light and Temperature
Printer format ### Your Questions How far does an edge affect light intensity and temperature within the forest? ### Background A continuous vegetation cover can modify the light environment in different ways, depending on the geometry of the plants, the distribution of plant biomass and the spectral properties and orientation of the leaves. Plant cover also has a significant and complex effect on the modification of the temperature regime. Tropical forests, especially in areas where human pressure is present, are subject to clearing, leaving sharp edges between two community types. The presence of a discontinuity in the vegetation cover can produce several effects on the microclimate of the forest. Many recent studies have shown that this effect extends variable distances into the forest, depending of the factor studied. In this study we will collect data on variation in two abiotic factors, light intensity and temperature with distance from the edge of a forest fragment towards the interior. Light intensity is probably the most important factor controlling plant growth in the understory of a forest ecosystem, since ### Your Assignment Measure light intensity and temperature variation along a transect from the forest edge into its interior and determine the extent of modification of the light and temperature regime in the forest as a function of distance from the forest edge. ### Methodology Task A—Establish sample areas Using maps and previous knowledge of the sites, select 2-3 forest areas with well defined edges and of similar structure At each site establish a transect of at least 200 m and at a perpendicular angle to the forest border and mark sampling stations Task B—Data collection Along each transect, collect data at regular intervals on light intensity and temperature (relative humidity also if possible) Task C—Data analysis and write up Data entry into computer Analyze the data Compare distances from forest edge Summarize results for presentation (written and oral) ### Objectives Introduce measurement techniques for abiotic variables Study edge effects on selected abiotic factors (light intensity and temperature) ### Key Skills Learning measuring techniques for two abiotic factors Reinforce capabilities in establishing transects Statistical comparisons ### Timetable Total time—1 day Morning Establish transects and sampling points Collect data Afternoon Finish data collection, if necessary Data entry and analysis Write up and discussion of results ### Materials Needed Field notebook and writing equipment Material for establishing transects (stakes, hammer, flagging) Tape measures (50 m) Compass and GPS Collection equipment for environmental data — radiation intensity and temperature (wet and dry bulb)