Plant life form classification and distribution at Suba Sebeta forest, Ethiopia

Abstract

A study focusing on altitudinal distribution of life forms of vascular plants was conducted in Suba Sebeta Forest, located 40 km west of Addis Ababa in Oromia National Regional State. The objective of the study was to document the life form composition of Suba Sebeta Forest based on life form spectrum. In the study, a systematic sampling method was employed to collect vegetation data from 48 (20 m x 20 m) plots. These entire quadrats included 16 (5 m x 5 m each) subplots to incorporate all life form types. Vegetation classification was done based on Raunkiaer’s major life form groups. R-Software (Version 2.15.1) Package was used to classify the life forms. The data were collected along altitudinal gradients, ranging from 2400 to 2870 m a.s.l. A total of 135 species belonging to 67 families were recorded from the study area; the results showed that Asteraceae was the dominant family accounting for 15.6% of the total record. Analysis of life form spectrum showed Phanerophytes as the dominant life form contributing 48 species (35.6%) followed by Hemicryptophytes (34 species, 25.18%), Chamaeophytes (22 species, 16.30%), Therophytes (20 species, 14.81%) and Geophytes (11 species, 8.15%). Correspondence analysis between life form and environmental gradients showed no significant relationship between life forms and soil pH while altitudinal difference affects the life form distribution. These life form variabilities along altitudinal gradient lay the foundation for further studies for monitoring of changes relating to climate change.

Key words/phrases: Life form, Life form spectrum, Raunkiaer, Suba Sebeta Forest.