Chapter 7 - Plant communities

Abstract

The present chapter offers a concise overview of the vegetation cover of the Pantepui province located between approximately 1500 and 3000m elevation in northeastern South America. This unique natural province, belonging to the biogeographical region of the Guiana Shield in the Neotropical region, presents a remarkable diversity of montane plant communities spread over c. 70 flat-topped table mountains (tepuis). The chapter is focused on the Venezuelan part of Pantepui, which contains the majority of these tepuis (c. 60) and where all vegetation studies have been developed. A total of 40 vegetation types are described, of which 12 correspond to forest formations, 10 to shrublands, and 18 are herbaceous communities. Pioneer formations of lithophytic algae, lichens, and bryophytes are mentioned but not classified. Some unique plant communities exclusive of Pantepui are described in more detail. This first preliminary recognition of 40 different vegetation types in the Pantepui floristic province indicates that even in mountains made essentially of Precambrian rock types and consisting mostly of siliceous sandstones poor in nutrients, a remarkably intensive and high level of speciation and physiological adaptations must have occurred during the development of the present table mountain physiography in the Guiana region. It is hoped that this study will encourage further ecological research on these plant formations, which is urgently needed not only for understanding their origin and development but also to guarantee their conservation.