Effect of food quality and availability on rainforest rodents of Sri Lanka

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P.B. Ratnaweera
M.R. Wijesinghe


Tropical rodent communities are highly diverse species assemblages, yet remain poorly studied. This investigation was conducted with the objective of examining the responses of rainforest rodents to food quality and availability. These factors were assessed through laboratory and field trials conducted in the Sinharaja and Kanneliya rainforests in Sri Lanka. The effect of food quality on the foraging behavior of rodents was examined through feeding experiments using natural rainforest fruits/seeds. In addition, the effect of food augmentation on the rodent population was also investigated. Diet choice experiments showed that rodents exhibited clear food preferences, with certain fruit types being preferentially consumed and others rejected. Tolerance tests where animals were provided with a single fruit type showed that some items that were avoided when offered with a range of food items were consumed when no alternatives were available. In the field a positive relationship was found between fruit/seed and rodent densities; seed addition resulted in marked increases in rodent numbers. These results suggest that tropical rodent populations are food limited, at least during seasons when fruits/seeds are in short supply. Food selectivity also means that populations of rainforest rodents might be adversely affected by changes in tree species composition resulting from habitat disturbance and fragmentation

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Author Biographies

P.B. Ratnaweera

Pamoda B. Ratnaweera is a Lecturer in Zoology at Uva Wellassa University, Sri Lanka. She has specialized in wildlife management during her undergraduate years.

M.R. Wijesinghe

Dr. Mayuri R. Wijesinghe is a Senior Lecturer in Zoology attached to the University of Colombo, Sri Lanka. Her expertise lies in the fields of Conservation Biology and Toxicology. Her research focuses on collecting baseline data on the distribution and habitat requirements of many rodents and shrews. She also studies the impact of agrochemicals and heavy metal pollutants on the survival, growth, development and histopathology of larval stages of amphibians.