Classification and ordination of understory vegeta

Authors: Inayat Ur Rahman Nasrullah Khan Kishwar Ali

Publish Date: 2017/03/07

Volume: 104, Issue: 3-4, Pages: 24-

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Abstract

An understory vegetation survey of the Pinus wallichianadominated temperate forests of Swat District was carried out to inspect the structure composition and ecological associations of the forest vegetation A quadrat method of sampling was used to record the floristic and phytosociological data necessary for the analysis using 300 quadrats of 10 × 10 m each Some vegetation parameters viz frequency and density for trees overstory vegetation as well as for the understory vegetation were recorded The results revealed that in total 92 species belonging to 77 different genera and 45 families existed in the area The largest families were Asteraceae Rosaceae and Lamiaceae with 12 ten and nine species respectively Ward’s agglomerative cluster analysis for tree species resulted in three floristically and ecologically distinct community types along different topographic and soil variables Importance value indices IVI were also calculated for understory vegetation and were subjected to ordination techniques ie canonical correspondence analysis CCA and detrended correspondence analysis DCA DCA biplots for stands show that most of the stands were scattered around the centre of the DCA biplot identified by two slightly scattered clusters DCA for species biplot clearly identified three clusters of species revealing three types of understory communities in the study area Results of the CCA were somewhat different from the DCA showing the impact of environmental variables on the understory species CCA results reveal that three environmental variables ie altitude slope and P mg/kg have a strong influence on distribution of stands and species Impact of tree species on the understory vegetation was also tested by CCA which showed that four tree species ie P wallichiana AB Jackson Juglans regia Linn Quercus dilatata Lindl ex Royle and Cedrus deodara Roxb ex Lamb G Don have strong influences on associated understory vegetation It is therefore concluded that Swat District has various microclimatic zones with suitable environmental variables to support distinct flora

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