Woody Perennial Diversity at Various Land forms of the Five Agro-Climatic Zones of Rajasthan, India

Abstract

Across the globe, the plant biodiversity have been gauged with many gradients like altitude/slope, grazing, nutrients and land uses. However, relationships between land forms and phyto-diversity have rarely been addressed. We compared the diversity of woody perennials at six different land forms of five agro-climatic zones of arid and semi-arid areas of Rajasthan, India. Characteristics of land forms (Hills and Piedmonts, Older Alluvial Plains [OAP], Sandy Undulating Hummocky Plains [SUHP], Younger Alluvial Plains [YAP], Sand Dune and Sandy Plains) along with generalized plant community succession trends were described. Five agro-climatic zones included arid Western, irrigated North Western plains, hyper arid partial irrigated, internal drainage dry zone and transitional plain of Luni basin. Thus, phyto-diversity was studied with land form specific as well as zonal specific approaches. Diversity patters were analyzed with help of species richness, diversity index (Shannon-Weaver index, H) and with evenness (E). SHE analysis was performed to quantify the patterns of these diversity patterns for a specific land form among the agro-climatic zones. Further, plant community behaviors under zonal and land form specific approaches were visualized through Principal Component Analysis (PCA). Our study identifies threshold limits (upper and lower) for different diversity parameters among agro climatic zones and at different land forms. Among the agro-climate zone, log normal (increase in dominance (S) and H but a decline in E) patterns were identified at SUHP, sandy plain, YAP and sand dune. While broken stick models (both S and H are expected to increase and E to stay constant) were identified at Hills and Piedmonts and at OAP. With this study, we identified zonal specific indicator species at different land forms. We linked the magnitude of land forms heterogeneity and their impacts on phyto-diversity. The present work can be extended with scientific inventories pertaining to effects of land forms on ecological roles of dominant/indicator species and effects of different pedological factors of such land forms on community composition and plant bio-diversity.