Rainforest trees face a threat 30 years post-logging, warns University of Exeter.
The next generation of trees in rainforests is facing a significant threat 30 years after logging, as revealed by recent research conducted by scientists from the University of Exeter. The study, published in the journal Global Change Biology, focused on monitoring over 5,000 seedlings for a year and a half in North Borneo, comparing natural forests with areas that had been logged three decades ago.
The researchers observed that rainforest seedlings had a higher chance of survival in natural forests compared to areas that had undergone logging, even if restoration efforts had been implemented. The study area contained both natural forests and areas that were either naturally recovering or restored through methods like tree planting.
A drought-triggered "mast fruiting" event led to a surge in fruit dropping from trees and new seedlings emerging across the region. Initially, both natural and restored forests showed high numbers of seedlings, indicating that restoration activities had enhanced fruit production. However, over time, low seedling survival in the restored forest led to equally low numbers of seedlings in both restored and naturally recovering forests, with higher seedling populations remaining in the natural forest.
The findings suggest that the regeneration of forests may face challenges based on the restoration approach used, such as seed availability in naturally recovering sites and seedling survival in areas with planted trees. This has implications for the long-term delivery of key ecosystem services like carbon sequestration.
Dr. Robin Hayward, who conducted the research during their PhD at the University of Stirling, expressed surprise at the lower seedling survival in restoration sites despite the initial productive fruiting event. Dr. David Bartholomew, from the University of Exeter and now at Botanic Gardens Conservation International, noted that the stress experienced by seedlings in logged forests could be due to changes in canopy structure, microclimate, and soil, with current restoration methods failing to alleviate this stress.
The study also highlighted the potential role of animal behavior in affecting seedling survival, with animals like bearded pigs being drawn to restored forest patches with abundant seeds and seedlings, impacting seed supplies differently in natural forests. Selective logging is common in tropical forests, and the low survival rates of seedlings three decades after logging raise concerns about future tree regeneration.
Dr. Lindsay F Banin from the UK Centre for Ecology & Hydrology emphasized the importance of understanding the mechanisms driving the observed patterns to support forest regeneration and long-term sustainability. The study underscores the need for carefully designed, monitored, and adaptive restoration projects to recover biodiversity and carbon stocks over time.
Different plant traits in logged areas compared to intact forests were observed, indicating that some species may struggle to survive in disturbed areas and may need to adapt growth patterns, potentially affecting biodiversity and ecological functioning in the long term. The study calls for longer-term research to fully comprehend the effects of historical disturbance on forests and improve seedling survival rates.
The study was conducted in the Danum Valley Conservation Area and the surrounding Ulu Segama landscape of North Borneo, focusing on the Dipterocarpaceae tree family dominant in intact forests, known for large inter-annual fruiting events. These cyclical events play a crucial role in food availability for animal species, highlighting the complex interactions within rainforest ecosystems.
In conclusion, the research sheds light on the challenges facing the next generation of trees in rainforests recovering from logging, emphasizing the importance of sustainable practices to ensure the long-term health and biodiversity of these vital ecosystems.
Source: https://www.eurekalert.org/news-releases/1037039
The researchers observed that rainforest seedlings had a higher chance of survival in natural forests compared to areas that had undergone logging, even if restoration efforts had been implemented. The study area contained both natural forests and areas that were either naturally recovering or restored through methods like tree planting.
A drought-triggered "mast fruiting" event led to a surge in fruit dropping from trees and new seedlings emerging across the region. Initially, both natural and restored forests showed high numbers of seedlings, indicating that restoration activities had enhanced fruit production. However, over time, low seedling survival in the restored forest led to equally low numbers of seedlings in both restored and naturally recovering forests, with higher seedling populations remaining in the natural forest.
The findings suggest that the regeneration of forests may face challenges based on the restoration approach used, such as seed availability in naturally recovering sites and seedling survival in areas with planted trees. This has implications for the long-term delivery of key ecosystem services like carbon sequestration.
Dr. Robin Hayward, who conducted the research during their PhD at the University of Stirling, expressed surprise at the lower seedling survival in restoration sites despite the initial productive fruiting event. Dr. David Bartholomew, from the University of Exeter and now at Botanic Gardens Conservation International, noted that the stress experienced by seedlings in logged forests could be due to changes in canopy structure, microclimate, and soil, with current restoration methods failing to alleviate this stress.
The study also highlighted the potential role of animal behavior in affecting seedling survival, with animals like bearded pigs being drawn to restored forest patches with abundant seeds and seedlings, impacting seed supplies differently in natural forests. Selective logging is common in tropical forests, and the low survival rates of seedlings three decades after logging raise concerns about future tree regeneration.
Dr. Lindsay F Banin from the UK Centre for Ecology & Hydrology emphasized the importance of understanding the mechanisms driving the observed patterns to support forest regeneration and long-term sustainability. The study underscores the need for carefully designed, monitored, and adaptive restoration projects to recover biodiversity and carbon stocks over time.
Different plant traits in logged areas compared to intact forests were observed, indicating that some species may struggle to survive in disturbed areas and may need to adapt growth patterns, potentially affecting biodiversity and ecological functioning in the long term. The study calls for longer-term research to fully comprehend the effects of historical disturbance on forests and improve seedling survival rates.
The study was conducted in the Danum Valley Conservation Area and the surrounding Ulu Segama landscape of North Borneo, focusing on the Dipterocarpaceae tree family dominant in intact forests, known for large inter-annual fruiting events. These cyclical events play a crucial role in food availability for animal species, highlighting the complex interactions within rainforest ecosystems.
In conclusion, the research sheds light on the challenges facing the next generation of trees in rainforests recovering from logging, emphasizing the importance of sustainable practices to ensure the long-term health and biodiversity of these vital ecosystems.
Source: https://www.eurekalert.org/news-releases/1037039
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