Prospects for mammals in Borneo’s selectively-logged tropical forests: looking beyond species richness and abundance
File(s)
Author(s)
Chapman, Philip Matthew
Type
Thesis
Abstract
The majority of tropical forest mammal species survive selective logging, however we have only recently begun to reveal complex, variable community abundance changes. We have little detailed, long-term data, and a poor mechanistic understanding of why mammals persist or decline. Predicting resilience remains elusive. In this thesis, we aimed to fill some of these knowledge gaps by (1) Examining long-term persistence of small mammals, (2) testing whether previously-observed small mammal abundance increases coincide with reduced body condition and demographic rates, potentially reducing future resilience, (3) testing for behaviourally plastic responses in large herbivore activity patterns, and (4) investigating whether the small mammal community “spills over” edges between logged forest and oil palm plantations.
We found strongly temporally variable small mammal population dynamics in logged forest, with some evidence for extinction debt. We found no direct evidence for bottom-up control seen in unlogged forest, although this probably reflects data limitations. There was no community-wide density-dependent reduction in body condition, reduced survival or reproductive output, suggesting that prospects for community resilience are good, but more detailed data is needed for declining species.
Large herbivores showed pronounced shifts in daily activity patterns, with the largest and most hunted ungulates becoming significantly more nocturnal. However, shifts did not predict persistence, suggesting the adaptive importance of behavioural plasticity is complex and species-specific. Lastly, we found little evidence that small mammals from logged forest spill over into adjacent plantations despite the abundant food, with the edge apparently forming a formidable dispersal barrier.
Together, our results suggest that prospects are good for many mammal species in logged forests, including those adjoining agriculture. However existing richness and abundance data miss many subtle temporal and individualistic responses, and to safeguard species known to be logging-intolerant, much more detailed work is required, combined with action to rehabilitate and restore logged forests for the future.
We found strongly temporally variable small mammal population dynamics in logged forest, with some evidence for extinction debt. We found no direct evidence for bottom-up control seen in unlogged forest, although this probably reflects data limitations. There was no community-wide density-dependent reduction in body condition, reduced survival or reproductive output, suggesting that prospects for community resilience are good, but more detailed data is needed for declining species.
Large herbivores showed pronounced shifts in daily activity patterns, with the largest and most hunted ungulates becoming significantly more nocturnal. However, shifts did not predict persistence, suggesting the adaptive importance of behavioural plasticity is complex and species-specific. Lastly, we found little evidence that small mammals from logged forest spill over into adjacent plantations despite the abundant food, with the edge apparently forming a formidable dispersal barrier.
Together, our results suggest that prospects are good for many mammal species in logged forests, including those adjoining agriculture. However existing richness and abundance data miss many subtle temporal and individualistic responses, and to safeguard species known to be logging-intolerant, much more detailed work is required, combined with action to rehabilitate and restore logged forests for the future.
Version
Open Access
Date Issued
2018-08
Date Awarded
2019-04
Copyright Statement
Creative Commons Attribution NonCommercial NoDerivatives Licence
Advisor
Ewers, Rob
Sponsor
Natural Environment Research Council (Great Britain)
Publisher Department
Life Sciences
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)