PHYTOSOCIOLOGICAL STUDIES OF DIVERSE AREAS RANGING FROM HARNAI,SINJAWITO DUll REGIONS

Abstract

Vegetation of hills, plains and water courses of the diverse areas ranging from Harnai, Sinjawi to Duki regions were studied by point centrad quarter method(Cottom and Curtis,1956). Plant communities were classified on the basis of index of similarity (Bray & Curtis,1957). Out of 111 stands,102 communities were thus recog- nized; 50 communities on the hills, 21 communities in the plains and 31 communities in the water courses. These co- mmunities were further grouped on altitudinal basis into four different ecological zones i.e. lower zone, lower middle zone, upper middle zone and upper .zone. The compo- sition of vegetation at different altitudes were deacribed. Plant communities of the hills, plains and water courses having first dominant common, were further grouped into di- fferent association types. The communities of hills were found to have high stand density and stand cover followed by plains and water courses. Both species diversity and vegetational diversity were found to be high on the hills followed by water courses and plains. High species diversity appears to be associated with soils having high maximum water holding capacity,organic -viii- matter and fine-texture. Certain ,communities of protected areas have also indicated high species diversity, and high coverage. The maturity and homogeneity of all the communi- ties of hills, plains and water courses were generally found to be low. The density size class structure of the communities of hills, plains and water courses revealed that in the trees and shrubs stratum, Olea ferruginea reproducing well in the communities of the hills, plains and water courses. Caragana ambigua and Prunus ~rahuica shows very well regen- eration in the communities of hills and plains. Juniperus polycarpos. Pistacia mutica. Cotoneaster nummularia, Acacia modesta, Abelia triflora and Caragana ulcina reproducing well in the communities of hills, and Fraxinus xanthoxyloid- ~ and Nannorhops ritchieana shows very well regeneration in the communities of water courses. In the herbs and under-shrubs stratum C:mbapogon jawarancusa is reproducing very well in the communities of hills, plains and water courses. Convolvulus spinsus, Thymus serpyllum and ChrYBOpogon aucheri are reproducing well in the communities of hills and plains. Eulaliopsis binata, Alopecu- -- --- --~ .~ - '----- -- - -ix- ~ arundinaceus, Plectranthus rugosus and DichaAthium foveolatum are reproducing well in the communities of hills. Artemisia stricta shows well regeneration in the communities of plains. Saccharum ravennae, Perovsk- ia abrotanoides, Saccharum bengalense, Salvia nubicola, Pennisetum orientale and Arundo donax we~e reproducing very well in the communities of water courses and appear to be very promising species for further. Among topographic factors, aspects seems to plaY an important role in the distribution of communities of hills. Similarly, wet water courses had Saccharum bengal- ense, Arundo donax, Cotoneaster nummularia, Dalbergia sissoo, etc. as the dominant species. Among the dry water courses, the dominant species differed in narrow, medium and wide water courses. The vegetation in sloping plains and flat plains also showed significant differences. Life form and leaf size spectra of the communities of the study areas were constructed according to Runkiaer (1905 & 1934). Hemicrytophytes, Therophytes and Chamaephy- tes were found to be significantly higher and Geophytes were found to be significantly lower than the "Normal spectrum" of Raunkiaer(1918). Life form spectrum of differ- ent ecological zone shows that Phanerophytes decrease gradu- ally from lower elevation to higher elevations. Chama- ephytes increase gradually from lower elevation to higher elevations. Microphyll leaf size class was found to be the highest percentage, followed by nannophylls. Leaf size spectrum of different ecological zone shows that lepto- phylls increase from lower zone to upper middle zone and the upper zone. Microphylls increase gradually from lower to upper zone. Soils of 102 communities were analysed for physical and chemical characteristics. Correlationat plant communi- ties with the edaphic factors have been discussed. Soil texture, maximum water holding capacity, organic matter, CaCO~, E.C., HCO~, Ca+Mg, Na, K, SAR and PAR were found to be important edaphic factors affecting the distribution of vegetation types. Importance values of dominant plants and soil cha- racteristics indicated that Cymbopogon jawarancusa shows sligh- tly.nigh positive correlation with silt and slightly high negative correlation with Ca+Mg. Saccharum ravennae shows slightly high positive correlation with silt and slightly high negative correlation with organic matter. TQymus ~ pyllum shows slightly high positive correlation with silt -xi- and slightly high negative correlation with sand. Cotoneaster n~ularia shows slightly high positive correlation with organic matter and slightly high negative correlation with maximum water holding capacity. Olea ferruginea shows slightly high positive correlation with K and slightly high negative correlation with CaC0 Juniperus polycarpos shows slightly high positive correla- tion with silt and slightly high negative correlation with CaCo3