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Crown Distortion and Elephant Distribution in the Woody Vegetations of Ruhuna National Park, Ceylon

Mueller-Dombois, Dieter
Ecology 1972 v.53 no.2 pp. 208-226
Elephantidae, dry season, dunes, feces, food plants, forests, monsoon season, national parks, shrublands, surveys, wet season, woody plants, Sri Lanka
A major wild elephant refuge occurs in the southeastern dry zone of Ceylon. The effect of the elephants on the woody vegetation is manifested in crown distortions mainly of the 2— to 5—m—tall woody plants. A survey of this phenomenon was made in 18 sample stands of four different structural woody vegetation types. A species crown—distorion index was established from summing the number of crown—distorted individuals in each species across the structural vegetation types. A list of species from high to low crown—distortion index is presented, which may serve as a guide to preferential elephant food plants for southeastern Ceylon. A stand crown—distortion index was established for each vegetation sample by summing the number of crown—distortion individuals per stand and relating these to the total number available. It was found that crown distortion is particularly high among earlier seral rather than late seral species, and stands, in spite of equal availability of both. This shows that the elephant is more strongly associated with disturbed and developing vegetation than with late seral or near—climax, evergreen, sclerophyll monsoon forest. Periodic elephant feces unts in wet and dry seasons indicated a shift and spread—out of current elephant activity into all structural woody vegetation types in the dry season, while during the wet season, elephant activity is more concentrated in areas of greater vegetation diversity with ready access to short—grass covers. Year—round centers of maximum activity were found in open Feronia (woodapple) scrub stands on grumusols and in evergreen forest—scrub on dunes.