Phytogeographic classification using multivariate approach; a case study from the Jambil valley Swat, Pakistan

摘要

Phytogeography is concerned with the past and present distribution of vegetation on the earth surface. The distribution of plants is neither even nor random on earth surface but follow a definite geographic pattern. The present study was aimed to find out phytogeographic pattern of plants distribution and subsequent classification of plant species of the Jambil Valley, District Swat Pakistan using multivariate statistic techniques. Sampling of vegetation was done using quadrats of 1 × 1 m 2 for herbs, 5 × 5 m 2 for shrubs and 10 × 10 m 2 for trees. The data were analyzed by PCORD v. 5 and CANOCO 4.5. The studies revealed that the vegetation of Jambil valley belongs to eighteen different phytogeographic elements. The highest percentage of elements (19.4%) belongs to Western-Himalayan region, followed by Cosmopolitan (13.9%), Eurasian (10.6%), Irano - turanian (10%), Paleotropical (9.4%), Eastern Asiatic and Mediterranean (6.7% each), Euro-Siberian (5.6%), Holoarctic (3.9%), Pantropical (3.3%), Sub-cosmopolitan (2.8%), Saharo-Arabian (2.2%), Eastern-Himalayan (1.7%), Central Asian and Neotropical (1.1% each), Pantemperate, Australian and Sudano-Zambezian (0.6% each). CANOCO correlated phytogeographical data with environmental factors, which showed significant effect of environmental variables on phytogeographical patterns. It is clear from our results that higher pH, electrical conductivity, moderate sand and silt, phosphorous and nitrogen have great impact on distribution of phytogeographical elements. The Western Himalayan elements having narrow geographic range require immediate attention and conservation efforts.