Luke Gibson et al.: forest fragments suffer small mammal community loss in just 5-25 years; invasive rat monoculture dominates

PhD student Luke Gibson, back from the field in Thailand, has published an alarming study with co-workers.

They had studied the native small mammal fauna in 16 of 100 forested islands in the Chiew Lam Reservoir in South Thailand, which was formed in 1986-1987. They report the disappearance of small mammal communities there, which was not observed in the larger mainland forest.

The study then derives an island biogeographic model for fragments of 50ha and less based on these findings.

Gibson et al. also highlight the relationship of species invasion and habitat fragmentation – almost all the islands are now dominated by the Malayan field rat Rattus tiomanicus. A secondary-forest species at best, its ability to exploit human modified landscapes suggest a potential to accelerate extinction rates in these situations.

This highly relevant work in light of increasing fragmentation complements previous work with birds, and highlights the need to preserve sufficiently large forest blocks to sustain tropical forest biodiversity.

The paper was widely reported, with many quoting the phrase Luke used to describe the results – “an ecological Armageddon”. Science writer Carl Zimmer writes in New York Times:

“Tropical forests are regularly cleared for logging, farming and cities. In most cases, the only original tree cover is reduced to isolated patches. Many of the original species of plants and animals may still survive in those fragments, but they experience new stresses. The edges of the fragments are no longer dim and humid, for example.

The small size of the surviving populations also creates problems. Over the course of a few generations, a small population can accumulate harmful mutations that make them less fertile or more vulnerable to diseases.

Scientists have hypothesized that many species will gradually decline in forest fragments until they become extinct. Reducing a vast carpet of jungle to isolated patches thus creates a so-called “extinction debt” that nature will sooner or later collect.”

Let’s hope these findings are injected into present conservation and management decisions sooner rather than later.

  • Gibson, L., A. J. Lynam, C. J. A. Bradshaw, F. He, D. P. Bickford, D. S. Woodruff, S. Bumrungsri, W. F. Laurance, 2013. Near-complete extinction of native small mammal fauna 25 years after forest fragmentation. Science, 341: 1508-1510. [link]
  • “In fragmented forests, rapid mammal extinctions,” by Carl Zimmer. The New York Times, 26 Sep 2013.
  • Forest fragmentation triggers ‘ecological Armageddon,’ by Mark Kinver. BBC News, 26 Sep 2013.
  • “One-two punch’ decimates small mammals,” by Anna Salleh. ABC Science, 27 Sep 2013.
Notification Center

Gibson_etal_Science_2013.pdf (page 3 of 3)

In Fragmented Forests, Rapid Mammal Extinctions -


Mon 23 Sep 2013: 2.00pm – 5.00pm @ LT20 – Tan Heok Hui on “Wet Scientific Photography”

“Scientific photography of aquatic organisms”

By Tan Heok Hui
Raffles Museum of Biodiversity Research
Department of Biological Sciences
National University of Singapore

Monday 23rd September 2013
Lecture Theatre 20

About the seminar – The seminar will cover basic principles of light photography, the different aspects of handling aquatic organisms for macro photography, gear and specimen preparation.

This is directed at environment biology students but all are welcome!

Jobs in freshwater ecology: Laboratory Assistant, Casual Employment, two positions (apply by 13 Sep 2013)

Ecological Monitoring, Informatics and Dynamics (EMID) research revolves around a cross-disciplinary, quantitative approach with a strong focus on operations and management, towards the overarching goal of sustainable resource management. The Inland Waters Cluster applies freshwater research through the development of assessment tools and environmetrics for ecological appraisal and prediction.

Sorting insects (FTK)

Laboratory Assistant, Casual Employment: two positions

The Inland Waters laboratory is actively seeking suitable candidates for the position of laboratory assistant to support various ongoing projects.


  • Assist in laboratory processing of benthic macorinvertebrate specimens such as Diptera larvae and Odonata nymphs obtained from streams and reservoirs in Singapore
  • Laboratory processing will include:
    1. picking out macroinvertebrates and separate them from detritus and sediment.
    2. Cataloguing and preservation of specimens in ethanol.
    3. Identification of specimens to Order and/or Family level using microscopes and dichotomous identification keys.


  • Experience and knowledge on aquatic macroinvertebrates and use of identification keys are desirable but ‘on-the-job’ training will be provided.
  • A conscientious attitude to laboratory work and keen interest in biology is essential.
  • Self-motivated and able to work independently with minimal supervision.

Payment will be made based on an hourly rate and shall commensurate with qualifications and experience.

Interested candidates are invited to email their detailed resume and cover letter to Rayson (email: and indicate in the subject heading: “RE: Lab Assistant (Inland_Waters)”

Deadline for Applications: 13 September 2013. Only short-listed candidates will be notified.