Approches analytiques d'évaluation de la diversité et de la valeur en ...

commonly used spreadsheet and is often already loaded in PC computers when they are
newly purchased. It is easily used to perform basic calculations and includes a variety of
statistical functions and a data analysis ToolPak. Our aim was also to familiarize
participants with the details of the various analyses, rather than teaching them software
without them understanding the basics of the calculations. The lectures included:
· Calculation operators in excel (arithmetic, comparison and reference operators)
· Entering standard and array functions
· Cleaning data with text functions
· Relative and absolute cell addresses
· Formatting cells
· Creating and editing graphs
· Building lists
· Analysing lists (simple statistics, sorting lists, using filters, etc.)
· Using statistical functions
· Building and working with pivot tables
Vegetation analysis
This part of the course was designed to familiarize the participants with basic analyses of
the vegetation in order to compare the diversity between different landscapes. The
lectures included calculations of species density, relative density, basal area, dominance,
relative dominance, frequency, relative frequency, and the importance value index, all
essential in describing forests where logging impacts, mammal food density, and
biodiversity need assessment. Other topics included diversity indices (Simpson’s Index,
Shannon’s index, Pielou’s Evenness), as well as similarity indices (Jaccard’s index,
Sorenson Index).
For tutorials we used a subset of data from the first census of the Korup Forest Dynamics
Plot (KFDP) in Cameroon. The 1.12 ha data included 28 quadrats of 20x20 m each from
7 topographical habitats of KFDP.
Evaluation of the conservation status of plant species
The participants were exposed to two methods of plant conservation measures. The
IUCN Redlist approach, based on individuals species and the ‘Star rating”, based on
species distribution data to evaluate the conservation status of a given forest, allowing the
choice of areas of high conservation priority. Both methods are increasingly being used to
evaluate the Congo Basin forests, and understanding their use and application is essential
for management. Students shared their experiences on conservation classification at their
project sites and in their respective countries. Emphasis was placed on IUCN
unclassified timber species as well as rare herbs that are often overlooked.
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