Lecture 3: Vegetation Sampling - Alaska Geobotany Center

En44ta4on and sample site requirements of
relevés:
Requirements of a sample site for a relevé
• Should be recognizable as unit that is repeated in other areas of the landscape, i.e. it is
a repea@ng assemblage of species.
• HOMOGENEITY of the vegeta@on canopy, soil, and other site factors.
• Large enough to contain all the species in the community, but small enough to sample
efficiently and not contain other vegeta@on types (minimum area).
The first step: en'ta'on
• The process of subdividing the vegeta4on into recognizable en44es or preliminary
vegeta4on types
• The first groupings should be at the “habitat type level”. (e.g. stream areas, talus slopes,
discrete soil types) recognizable units on aerial photos, obvious physiognomic
differences.
• Start with the largest easiest to recognize units.
• Reconnaissance essen@al (cannot be overemphasized) The beXer your ini@al
knowledge of an area, the beXer will be the subsequent sampling.
• Important to avoid sampling ecotones or breaks between dis@nct communi@es.
• Knowledge of exis@ng literature and experience in other areas help.
• More subtle floris@c differences will become apparent later.
• Itera@ve process that may take several aXempts to perfect descrip@on of the
communi@es.