Biology subjects

Turner, E. C.

Publications and source records attributed to Turner, E. C..

4 recordsLinked to original sources

bioRxiv2026

Planting set-up and local environmental conditions affect outcomes in tropical agricultural restoration

1. Fine-scale environmental metrics, including spatial configuration and identity of surrounding plants, can strongly influence plant survival and ecosystem functioning. However, tropical restoration projects rarely test their role. Within the Riparian Ecosystem Restoration in Tropical Agriculture (RERTA) Project, located within oil palm plantations in Indonesia, we investigated how the spatial configuration and position of enrichment-planted trees influenced restoration outcomes within actively restored riparian margins. 2. We compared the enrichment plantings' response to fine-scale spatial conditions, either planted with conspecific (same-species) or heterospecific (mixed-species) neighbours for six planted tree species (Peronema canescens, Shorea leprosula, Alstonia scholaris, Artocarpus integer, Calophyllum inophyllum, and Albizia chinensis), in restoration areas with mature oil palms either left in place (shaded) or removed (unshaded). We also tested whether restoration outcomes varied with position within the margin (river, middle, or edge). We measured plantings response as seedling survival and height (monitored over eight years) for all six species of trees. 3. We also carried out more detailed observation on multiple ecosystem functions associated with focal trees of three of the species (Peronema canescens, Alstonia scholaris, and Albizia chinensis), measuring differences by planting configuration and distance to river edge. Functions measured included: herbivore predation, leaf herbivory, litterfall, soil chemical properties (organic carbon, cation exchange capacity, total nitrogen, and phosphorus), and soil physical properties (bulk density, aggregate stability, friable soil content, and A-horizon depth). 4. Survival and height did not differ between conspecific and heterospecific neighbours, but did with position within the riparian margin, but only when analysed by treatment and time. Planting configuration and position influenced ecosystem functions; heterospecific plantings had greater soil aggregate stability and higher ant densities, while increasing distance from the river was associated with lower arthropod abundance and herbivory but greater predation. 5. Our findings demonstrate that planting outcomes are strongly context-dependent, with local seedling configurations, position within the riparian margin, and restoration treatment interacting to influence restoration success and local ecological conditions. Our findings provide experimental results to inform planting strategies and restoration protocols in agricultural landscapes.

ecology↗

bioRxiv2026

From margins to mainstream: restoration of riparian margins to support oil palm sustainability in modern and future climates

Palm oil is the worlds leading vegetable oil, with production continuing to expand, particularly across Southeast Asia. Within established plantations, conserving and restoring riparian margins can reduce erosion, improve connectivity, and support biodiversity. Simultaneously, climate change is increasing thermal stress within tropical agricultural landscapes, raising the potential importance of riparian buffers as microclimatic refugia, although this has not previously been evaluated. The Riparian Ecosystem Restoration in Tropical Agriculture (RERTA) Project is a long-term Before-After Control-Impact experiment established within oil palm plantations in Riau, Indonesia, to evaluate alternative riparian restoration strategies following plantation replanting. Treatments included passive restoration (retaining mature oil palms and allowing natural regeneration), active restoration (enrichment planting with six native tree species), and a control (replanting immature oil palms to the river edge). Six years after restoration, we assessed vegetation structure using terrestrial laser scanning and thermal stability using temperature loggers and thermal imaging. We also evaluated the long-term temperature buffering capacity of each treatment under current and projected climates using CHELSA climate data and downscaled outputs from multiple General Circulation Models under Shared Socioeconomic Pathway scenarios for 2045 and 2085. Active restoration produced greater structural complexity, a more closed canopy, and cooler, more thermally stable conditions than passive restoration and control treatments. Restored margins also contained significantly more cool surface microhabitats, reducing thermal extremes under both current and future climate scenarios. Our findings demonstrate that active restoration of riparian margins can enhance thermal buffering and create microclimatic refugia for biodiversity within tropical oil palm landscapes. As agricultural intensification and climate change continue to reshape tropical ecosystems, restoring structurally complex riparian vegetation will be critical for sustaining biodiversity and the ecosystem services upon which agricultural production depends.

ecology↗

bioRxiv2022

Logging alters tropical forest structure, while conversion reduces biodiversity and functioning

The impacts of degradation and deforestation on tropical forests are poorly understood, particularly at landscape scales. We present an extensive ecosystem analysis of the impacts of logging and conversion of tropical forest to oil palm from a large-scale study in Borneo, synthesizing responses from 82 variables categorized into four ecological levels spanning a broad suite of ecosystem properties: 1) structure and environment, 2) species traits, 3) biodiversity, and 4) ecosystem functions. Responses were highly heterogeneous and often complex and non-linear. Variables that were directly impacted by the physical process of timber extraction, such as soil structure, were sensitive to even moderate amounts of logging, whereas measures of biodiversity and ecosystem functioning were generally resilient to logging but more affected by conversion to oil palm plantation. One-Sentence SummaryLogging tropical forest mostly impacts structure while biodiversity and functions are more vulnerable to habitat conversion.

ecology↗

bioRxiv2018

Forest quality, forest area and the importance of beta-diversity for protecting Borneo’s beetle biodiversity

The lowland forest of Borneo is threatened by rapid logging for timber export and clearing for the expansion of timber and oil palm plantations. This combination of processes leaves behind landscapes dotted with small, often heavily-degraded forest fragments. The biodiversity value of such fragments, which are easily dismissed as worthless, is uncertain. We collected 187 taxa of rove beetles across a land-use gradient in Sabah, Malaysia, spanning pristine tropical lowland forest to heavily-degraded forest. Using these data, we identified shifts in alpha-, beta-, and gamma-diversity in response to forest quality and distance, then applied our findings from continuous expanses of forest to make predictions on hypothetical forest areas. We found that maintaining high forest quality is more important than forest area for conserving rare taxa (those important for conserving biodiversity per se), and that very small areas (10 ha) are likely to harbour the same richness of rove beetles as larger areas (100 ha) of equal forest quality. We estimate a decline in richness of 36% following heavy logging (removal of 95% of the vegetation biomass) from a forest area of 100 ha or less. Maintaining large forest area as well as high forest quality is important for conserving community composition, likely to be more important for conserving ecosystem functioning. We predict a decline of 35% in community diversity in conversion of a 100 ha area of unlogged forest to a 10 ha area of heavily-logged forest. Despite significant declines in alpha-diversity, beta-diversity within small rainforest areas may partially mitigate the loss of gamma-diversity, reinforcing the concept that beta-diversity is a dominant force determining the conservation of species in fragmented landscapes. In contrast to previous findings on larger animals, our results suggest that even small fragments of degraded forest might be important reservoirs of invertebrate biodiversity in tropical agriculture landscapes. These fragments, especially of lightly-logged forest, should be conserved where they occur and form an integral part of management for more sustainable agriculture in tropical landscapes.

ecology↗