Plant selection and avoidance by the Bornean elephant (Elephas maximus borneensis) in tropical forest: does plant recovery rate after herbivory influence food choices?

Abstract

Abstract:The plant vigour hypothesis proposes that herbivores should favour feeding on more vigorously growing plants or plant modules. Similarly, we would expect herbivores to favour plants that regrow vigorously after herbivory. Larger animals, like elephants, may also select plant species relative to their availability and prefer species with larger growth forms in order to meet their intake requirements. The food preferences of the Bornean elephant (Elephas maximus borneensis) in the Lower Kinabatangan Wildlife Sanctuary, Sabah, Malaysia, were investigated along 12 transects in areas where elephants were recently sighted feeding. One hundred and eighty-two plants were eaten and 185 plants were measured for species availability along transects. Species vigour was determined by the monthly regrowth in new shoot length after elephant feeding and the number of new shoots produced on each plant. Measurements were carried out on each plant for 9 mo or until the new shoot was eaten. Plant sizes were determined from their basal diameter. The Bornean elephant did not prefer more vigorous species or species with larger growth forms. New shoots did not grow longer on preferred than avoided species. Additionally, unlike other elephants that live in a forest environment, the Bornean elephant preferred species from the Poaceae (specifically Phragmites karka and Dinochloa scabrida) over other plant types including gingers, palms, lianas and woody trees.

Foraging site recursion by forest elephants Elephas maximus borneensis

“…Additionally, elephants fed more on grasses and bamboos at recursion sites compared to sites they did not return to. Grasses and bamboos are most commonly found in the riverine and open grass habitats along forest margins (English et al, 2014) where elephants spent more time at recursion.…”

“…We expected elephants to spend more time at recursion sites compared to non-recursion sites if the former were higher quality, such as those sites containing preferred food plants like grasses and bamboos (English et al, 2014). Additionally, we expected elephants to return to sites at two temporal scales.…”

“…We also expected site characteristics such as habitat type, distance to water, distance to human habitation, shade and understorey cover to influence recursion and the intensity of site use. We expected more intensive use of sites within habitats containing preferred food plants of the Bornean elephant, such as within riverine and open grass areas along forest margins (English et al, 2014), sites closer to a water source (McKay, 1973;Sukumar, 1990), sites further from human habitation (Blake, 2002) and sites less shaded (Barnes et al, 1995;Powell, 1997) allowing for more understorey growth, in particular grasses and bamboos (McKay, 1973;Shoshani and Eisenberg, 1982).…”

An Approach for Foliar Trait Retrieval from Airborne Imaging Spectroscopy of Tropical Forests

“…2018, 10, x FOR PEER REVIEW 3 of 21 natural canopy of the lowland portion of the study region is dominated by the plant family Dipterocarpaceae [18], which is not found in the Neotropics. The lowland study sites include a diverse set of substrates in the western portion of the state, including fertile alluvial substrates along the Kinabatangan river [19], sedimentary substrates found in the Danum Valley [20], and fertile alluvial and infertile sandstone substrates in the Sepilok Forest Reserve (Table 1; [21]). The elevation at these lowland sites varies from 15 m to 150 m above sea level (asl).…”

Foraging ecology and diet of Bornean elephants(Elephas maximus borneensis)in the Sebuku forest area, North Kalimantan Province of Indonesia: Do the choices matter?

“…Depending on nutritional requirements, selective feeding behavior may also vary seasonally (Sukumar 1992). In Borneo, however, where rainfall is common throughout the year, the effect of seasonality is suggested to be less pronounced (MacKinnon et al 1996;English et al 2014). However, the wet tropical forests of Borneo are characterized by irregular mast fruiting events.…”