BiologybioRxiv
Ranked by formulaVerdict: NotableLong-term Population Dynamics and Conservation of Proboscis Monkeys (Nasalis larvatus) in the Lower Kinabatangan, Sabah, Malaysia
Long-term ecological monitoring is essential for evaluating the effectiveness of conservation actions for long-lived tropical primates, yet few studies have integrated repeated population censuses with habitat-change…
Key numbers
- 66% and 72% respectively compared
Caveats
- Preprint; not yet peer reviewed.
VerdictWorth a reader's time today.
Abstract
Long-term ecological monitoring is essential for evaluating the effectiveness of conservation actions for long-lived tropical primates, yet few studies have integrated repeated population censuses with habitat-change analyses. We evaluated long-term population and habitat dynamics of the endangered proboscis monkey (Nasalis larvatus) in the Lower Kinabatangan, Sabah, Malaysian Borneo, by integrating a landscape-wide population survey conducted in 2025 with previous surveys from 2005 and 2014, long-term monitoring at three representative sites, and spatial analyses of land-use and land-cover change. Standardized late-afternoon boat-based surveys covering approximately 223 km of the Kinabatangan River and its tributaries recorded an estimated 2,420 individuals in 174 social groups, representing an increase of approximately 66% and 72% respectively compared with the 2005 survey. Group sizes (number of individuals per social group) remained largely unchanged despite the overall increase in population size. Long-term monitoring at three representative sites indicated stable population trajectories throughout the study period. Habitat analyses further revealed an increase in natural vegetation and limited conversion of forest to oil palm within protected areas between 2005 and 2025. Together, these independent lines of evidence indicate that the Lower Kinabatangan proboscis monkey population has recovered while maintaining overall demographic stability under long-term habitat protection. Nevertheless, substantial areas of suitable habitat remain outside the protected-area network, highlighting opportunities for additional habitat restoration and improved landscape connectivity. Our findings demonstrate the value of integrating long-term ecological monitoring with landscape-scale habitat assessment to inform adaptive conservation management in fragmented tropical landscapes.
The editor's rubric
| Dimension | Level | Weight | What that level means |
|---|---|---|---|
| Leverage | ███░░ 3 | 24% | A method or resource many groups across the field will adopt within a year. |
| Magnitude | ███░░ 3 | 16% | Large gain: roughly 2x, or a clear new state of the art on a hard, unsaturated problem. |
| Evidence | ███░░ 3 | 20% | Solid: multiple benchmarks or cohorts, ablations, fair baselines, released code or data. |
| Novelty | ██░░░ 2 | 20% | A new combination of known ideas. |
| Trajectory | ███░░ 3 | 10% | A clear path to scale. |
| Stakes | ██░░░ 2 | 10% | Benefits a professional community (practitioners, clinicians, engineers). |
Editor’s rationale
Heuristic triage from title and abstract text only, not a reading of the paper. Cues found: breadth (many tasks); gains (relative gain); verification (independent replication); scale (scalable).
How the score was computed
- Merit
- 5.4 / 10
- Adjusted merit
- 4.5 / 10
- Attention
- 0%
- Freshness
- 88%