Abstract
Recent advances in remote sensing such as airborne laser scanning have revolutionized our ability to accurately map forest canopy gaps, with huge implications for tracking forest dynamics at scale. However, few studies have explored how canopy gaps vary among forests at different successional stages following disturbances, such as those caused by logging. Moreover, most studies have focused exclusively on the size distribution of gaps, ignoring other key features such as their spatial distribution and shape. Here, we test a series of hypotheses about how the number, size, spatial configuration, and geometry of gaps vary across a logging disturbance gradient in Malaysian Borneo. As predicted, we found that recently logged forests had much higher gap fraction compared to old-growth forests, a result of having both a greater total number of gaps and a higher proportion of large gaps. Regrowing forests, on the other hand, fell at the opposite end of the spectrum, being characterized by both fewer and smaller gaps compared to nearby old-growth forests. Across all successional stages gaps were found to be spatially clustered. However, logging significantly diluted the degree of spatial aggregation and led to the formation of gaps with much more complex geometries. Our results showcase how logging and subsequent regrowth substantially alter not just the number and size of gaps in a forest, but also their spatial arrangement and shape. Linking these emergent patterns to their underlying processes is key to better understanding the impacts of human disturbance on the structure and function of tropical forests.
| Original language | English |
|---|---|
| Number of pages | 14 |
| Journal | Biotropica |
| Early online date | 15 Dec 2022 |
| DOIs | |
| Publication status | E-pub ahead of print - 15 Dec 2022 |
Bibliographical note
Funding Information:We thank NERC's Airborne Research Facility and Data Analysis Node for conducting the airborne laser scanning (ALS) survey and Tom Swinfield for help with processing the ALS point cloud data. We acknowledge the Sabah Biodiversity Centre, Sabah Biodiversity Council, Maliau Basin and Danum Valley Management Committees and the Economic Planning Unit for their support, access to field sites and for permission to carry out the ALS surveys in Sabah. We also wish to thank the South East Asia Rainforest Research Partnership (SEARRP), Sabah Foundation, Benta Wawasan, the State Secretary, Sabah Chief Minister's Departments, and the Sabah Forestry Department. Finally, we are extremely grateful to Wan Shafrina Wan Mohd Jaafar for translating the abstract of the paper into Malay. The acquisition of the ALS data was funded through a grant awarded to the BALI consortium through NERC's Human Modified Tropical Forests Programme (grant code: NE/K016377/1). TJ was supported by a NERC Independent Research Fellowship (grant code: NE/S01537X/1) and through a Research Project Grant from the Leverhulme Trust which also funded FJF (grant code: RPG‐2020‐341). BZ was funded by a Scholarship from the China Scholarship Council (grant code: 202008320276).
Publisher Copyright:
© 2022 The Authors. Biotropica published by Wiley Periodicals LLC on behalf of Association for Tropical Biology and Conservation.