Grants & Prizes Ecological Opportunities Fund Honours, Awards and Prizes Building Capacity for Ecology Fund Honorary Member List Research grants General notes Grants to attend meetings & courses Grants to run meetings & events Grant reports List of Tansley Lectures

SEPG 1824 - Date Awarded 2000

The effects of refuse feeding on the demography and behaviour of the banded mongoose

Jason S. Gilchrist¹ & Emily Otali¹²

¹ Large Animal Research Group, Department of Zoology, University of Cambridge, Downing Street, CB2 3EJ, Cambridge, UK.
² Makerere University Institute of Environment and Natural Resources, PO BOX 7298, Kampala, Uganda.

Abstract

Food availability affects the ecology of individuals and groups. Human refuse tips, where waste food is dumped, often represent sources of concentrated artificial food to wild animals. The effects of refuse sites on wild animals are particularly relevant to the management of national parks with human waste sites within, or on their boundary.

The banded mongoose (Mungos mungo) is a cooperative breeding mammal, found in territorial groups. We studied these animals in Queen Elizabeth National Park, Uganda, over a three-year period, where three of our eleven study groups had access to artificial food at refuse tips around the Park Headquarters. Using a combination of live trapping, radio tracking and behavioural observation we contrasted spatial use, demography, body condition and reproductive success between refuse and non-refuse feeding groups.

Refuse feeding groups had smaller home ranges than non-refuse feeding groups, concentrated their home range use around refuse sites, and tended to contain more members. Where groups shared access to a refuse tip, fights between them were more common. Refuse sites attracted marabou storks, which were observed to predate pups. Although individuals with access to refuse were in better physical condition, reproductive success was no greater than in groups without access to refuse.

In conclusion, the effects of access to a concentrated artificial food source on group living banded mongooses were both beneficial and detrimental. Although refuse tips are not necessarily bad for mongooses, they clearly effect their demography and behaviour. This is unlikely to be desirable in national parks, where usually one of the aims is to conserve the natural balance of the ecosystem.

Introduction

Food availability is an important factor affecting the ecology of individuals and groups. Spatial use, aggression, physical condition and reproductive success are all affected by food availability. Human refuse tips, where waste food is dumped, often represent sources of concentrated artificial food to wild animals. Such refuse sites provide an opportunity to evaluate the effects of concentrated food supplies on the ecology of animals. The effects of refuse sites on wild animals are particularly relevant to the management of national parks, where human habitation and waste sites often occur within, or on the boundary, and may affect the population dynamics of species within the protected area.

The banded mongoose (Mungos mungo) is a cooperative breeding mammal, found in territorial groups of 5 to 30 members, within which females breed synchronously and most group members care for the pups (Rood 1975; Cant 2000). We studied these animals in Queen Elizabeth National Park, Uganda, where three of our eleven study groups had access to artificial food at refuse tips around the Park Headquarters. We predicted that mongoose groups with access to refuse (and therefore a concentrated source of artificial food) would have smaller home ranges, and be more concentrated in their home range use (specifically around the refuse area) than non-refuse feeding groups, and for there to be a higher frequency of inter-group encounters between groups that shared access to a refuse tip. We also predicted that individuals in groups with access to refuse would be in better condition and consequently have improved reproductive success relative to non-refuse feeding individuals. Finally we predicted that mortality of individuals in refuse feeding groups would be less than that in non-refuse feeding groups.

Methods

We monitored 542 mongooses from January 1998 to January 2000, in eleven groups, three of which had refuse tips in their home range. Of these, behavioural and demographic data were collected on nine habituated groups including one group just outside the peninsula. The two un-habituated groups farther off the peninsula were only used in analysis of trapping data. The study site, Mweya peninsula, covers 5 km² and houses the headquarters of the national park. It contains a stable population of approximately 500 - 700 park and lodge staff, plus additional tourists, and hence numerous refuse tips where waste food is available. We defined refuse tips as human refuse disposal sites. The foodstuffs available to mongooses at refuse tips included meat, fish, fowl, gravy, rice and a variety of local foods.

Mongooses were captured in baited live traps approximately every 2 months. Trapped animals were anaesthetised. While immobilised, individuals were weighed and morphometric measurements were taken. One group member was fitted with a radio collar and the location of the group (based upon a map of the study site divided into 100 x100 metre grid squares) was recorded at the beginning of each visit (approximately once per day). The error bars in the figures represent O 1 standard error.

Results and Discussion

Refuse feeding groups had smaller home ranges than non-refuse feeding groups, concentrated their home range use around refuse sites, and tended to contain more members. Where groups shared access to a refuse tip, fights (which could lead to injury and even death) between them were more common than for groups that did not share access to the resource. Refuse sites also attracted potential mongoose predators, especially marabou storks, which were observed to predate pups, and consequently suffered a higher mortality rate of male pups. Although individuals with access to refuse were in better physical condition, and females tended to carry more foetuses, reproductive success was no greater in groups with access to refuse, than those without: there was no difference in conception rate or the number of independent pups per female between refuse and non-refuse feeding females.

In conclusion, the effects of access to a concentrated artificial food source on a group living cooperative mammal, the banded mongoose, were both beneficial and detrimental. Although it is not clear that refuse tips are bad for mongooses (or for other animals attracted to refuse e.g. warthogs, monitor lizards and marabou storks), they clearly have an important affect on their demography and behaviour. This is unlikely to be desirable in national parks, where usually one of the aims is to conserve the natural balance of the ecosystem.

References

Cant, M. A. 2000. Social control of reproduction in banded mongooses. Animal Behaviour, 59, 147-158.

Rood, J. P. 1975. Population dynamics and food habitats of the banded mongoose. East African Wildlife Journal, 13, 89-111.

Publications:

Otali, E. & Gilchrist, J.S. 2004. The effects of refuse feeding on body condition, reproduction and survival of banded mongoose. Journal of Mammalogy, 85, 491-497

Gilchrist, J.S. & Otali, E. 2002 The effects of refuse-feeding on home-range use, group size, and intergroup encounters in the banded mongoose.Canadian Journal of Zoology, 80, 1795-1802

Copyright 2007 British Ecological Society. All Rights Reserved