Recursion to food plants by free-ranging Bornean elephant.
Plant recovery rates after herbivory are thought to be a key factor driving recursion by herbivores to sites and plants to optimise resource-use but have not been investigated as an explanation for recursion in large herbivores. We investigated the relationship between plant recovery and recursion by elephants (Elephas maximus borneensis) in the Lower Kinabatangan Wildlife Sanctuary, Sabah. We identified 182 recently eaten food plants, from 30 species, along 14 × 50 m transects and measured their recovery growth each month over nine months or until they were re-browsed by elephants. The monthly growth in leaf and branch or shoot length for each plant was used to calculate the time required (months) for each species to recover to its pre-eaten length. Elephant returned to all but two transects with 10 eaten plants, a further 26 plants died leaving 146 plants that could be re-eaten. Recursion occurred to 58% of all plants and 12 of the 30 species. Seventy-seven percent of the re-eaten plants were grasses. Recovery times to all plants varied from two to twenty months depending on the species. Recursion to all grasses coincided with plant recovery whereas recursion to most browsed plants occurred four to twelve months before they had recovered to their previous length. The small sample size of many browsed plants that received recursion and uneven plant species distribution across transects limits our ability to generalise for most browsed species but a prominent pattern in plant-scale recursion did emerge. Plant recovery time was a good predictor of time to recursion but varied as a function of growth form (grass, ginger, palm, liana and woody) and differences between sites. Time to plant recursion coincided with plant recovery time for the elephant's preferred food, grasses, and perhaps also gingers, but not the other browsed species. Elephants are bulk feeders so it is likely that they time their returns to bulk feed on these grass species when quantities have recovered sufficiently to meet their intake requirements. The implications for habitat and elephant management are discussed.
Centre for Biodiversity and Restoration Ecology, School of Biological Sciences, Victoria University of Wellington , New Zealand.
Megan
M
English
Department of Zoology, University of Melbourne , Parkville, Victoria , Australia.
Graeme
G
Gillespie
Danau Girang Field Centre, c/o Sabah Wildlife Department , Kota Kinabalu, Sabah , Malaysia ; Organisms and Environment Division School of Biosciences, Cardiff University , Cardiff , UK ; Sabah Wildlife Department , Kota Kinabalu, Sabah , Malaysia.
Benoit
B
Goossens
HUTAN Elephant Conservation Unit and Kinabatangan Orangutan Conservation Project , Sukau Sabah , Malaysia.
Sulaiman
S
Ismail
HUTAN Elephant Conservation Unit and Kinabatangan Orangutan Conservation Project , Sukau Sabah , Malaysia.
Marc
M
Ancrenaz
Centre for Biodiversity and Restoration Ecology, School of Biological Sciences, Victoria University of Wellington , New Zealand ; Centre for African Conservation Ecology, Nelson Mandela Metropolitan University , Port Elizabeth , South Africa.
Wayne
W
Linklater
Elephant feeding behaviour; Herbivore ecology; Herbivore-resource relationships; Re-browsing; Recursion