Vertical distribution, resource and space use in a tropical rainforest small mammal community

Rader, Romina (2005) Vertical distribution, resource and space use in a tropical rainforest small mammal community. Masters (Research) thesis, James Cook University.

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Abstract

Mammal assemblages of rainforest communities are commonly vertically stratified. This can be driven by competition for or access to resources in the upper canopy layers of the forest. Arboreal mammals comprise a substantial proportion of tropical mammal communities and yet are difficult to census due to their inaccessibility and often, cryptic and nocturnal behaviour. Nonetheless they require attention to ensure they are appropriately managed. This study found the rodent community of Cape Tribulation to be vertically stratified with Pogonomys mollipilosus found only in the upper canopy layers and Rattus leucopus on the ground. Melomys cervinipes and Uromys caudimaculatus were found at all four height layers. Fruit and flower resource abundance were not significantly correlated with total rodent captures, however arboreal captures of M. cervinipes and P. mollipilosus were correlated with the number of individual flowering canopy trees.

The consumption of fruits by vertebrates and invertebrates may be both advantageous and detrimental to seeds. The consumption of Acmena graveolens fruit pulp by rodents and beetle presence, increases the germination success of A. graveolens seeds. Germination success is also higher as seed size increases and seed size influences the amount of pulp remaining on seeds. In this study, both vertebrate and invertebrate interaction with the fruit appears advantageous.

Nesting and resource availability were identified as two mechanisms driving arboreal activity of M. cervinipes, a scansorial rainforest rodent. Home range size does not significantly differ between the sexes. The number of canopy trees increased linearly with area size for the 95% harmonic mean area but the average number of canopy trees remained the same regardless of area for core home range areas.

The salient points of this study are as follows: 1. Arboreal trapping is an important part of biodiversity assessment of forest-dwelling small mammal communities 2. Removal of pulp by rodents and beetle presence enhances germination success of A. graveolens seeds 3. The number of canopy trees influences core home range size of M. cervinipes

Understanding the full extent of rodent resource use, including fruit consumption, is important to increase our knowledge and understanding of community dynamics, the associated impacts upon seed survival and in the long term, the structuring of plant communities and maintenance of diversity in tropical rainforests.

Item ID: 17511
Item Type: Thesis (Masters (Research))
Keywords: tropical rainforests, mammals, rodents, arboreal, vertical distribution, canopy levels, resource use, canopy trees, frugivory, seed germination, seed survival, plant communities, structure, diversity
Date Deposited: 28 Nov 2011 23:26
FoR Codes: 06 BIOLOGICAL SCIENCES > 0602 Ecology > 060208 Terrestrial Ecology @ 50%
06 BIOLOGICAL SCIENCES > 0608 Zoology > 060801 Animal Behaviour @ 50%
SEO Codes: 96 ENVIRONMENT > 9608 Flora, Fauna and Biodiversity > 960806 Forest and Woodlands Flora, Fauna and Biodiversity @ 50%
96 ENVIRONMENT > 9605 Ecosystem Assessment and Management > 960504 Ecosystem Assessment and Management of Farmland, Arable Cropland and Permanent Cropland Environments @ 50%
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