Interrelationships of biological spectra, life-form, landform and functional vegetation type in the riparian forests of a tropical river

Abstract

The relative dominance of life-forms in a riparian forest can be related to the landforms and functional vegetation types and which is considered as the primary requirement for any restoration effort. We examined the functional vegetation types, life-forms and landforms in a riparian forest of tropical river Pamba of Western Ghats by 52 transects (2 km length and 10–30 m width. The riparian forests have 31 pteridophytes, 3 gymnosperms and 545 angiosperms, comprising 16 chamaephytes, 31 cryptophytes, 17 epiphytes, 10 helophytes, 22 hemicryptophytes, 17 hydrophytes, 158 small phanerophytes, 170 large phanerophytes and 138 therophytes. The Canonical Correspondence Analysis (CCA) indicated that life-form distribution largely based on landform and a combined effect of landform features, longevity, elevation and disturbance regime resulted in resister, avoider, endurer and invader functional vegetation types. Therophyte dominance in floodplains indicated flood disturbances and terrain modification. Ochrenauclea missionis, Crataeva magna, Neolamarckia cadamba and Lagerstroemia speciosa prefers floodplain and protect from bank erosion. Leea indica, Pandanus odorifer and Tetrameles nudiflora have prop-roots, stilt roots and buttress formation against inundation. High range trees Actinodaphne wightiana and Persea macrantha prefer hydrochory for recruitment in the midlands and lowlands. The identified species were resister in functional group and prefer floodplain as their landform preference. The research provides baseline data for designing a nature based riparian buffer system with resister and endurer species for restoration.