Impact of Logging and Forest Conversion to Oil Palm Plantations on Soil Bacterial Communities in Borneo

Abstract

cTropical forests are being rapidly altered by logging and cleared for agriculture. Understanding the effects of these land use changes on soil bacteria, which constitute a large proportion of total biodiversity and perform important ecosystem functions, is a major conservation frontier. Here we studied the effects of logging history and forest conversion to oil palm plantations in Sabah, Borneo, on the soil bacterial community. We used paired-end Illumina sequencing of the 16S rRNA gene, V3 region, to compare the bacterial communities in primary, once-logged, and twice-logged forest and land converted to oil palm plantations. Bacteria were grouped into operational taxonomic units (OTUs) at the 97% similarity level, and OTU richness and local-scale ␣-diversity showed no difference between the various forest types and oil palm plantations. Focusing on the turnover of bacteria across space, true ␤-diversity was higher in oil palm plantation soil than in forest soil, whereas community dissimilarity-based metrics of ␤-diversity were only marginally different between habitats, suggesting that at large scales, oil palm plantation soil could have higher overall ␥-diversity than forest soil, driven by a slightly more heterogeneous community across space. Clearance of primary and logged forest for oil palm plantations did, however, significantly impact the composition of soil bacterial communities, reflecting in part the loss of some forest bacteria, whereas primary and logged forests did not differ in composition. Overall, our results suggest that the soil bacteria of tropical forest are to some extent resilient or resistant to logging but that the impacts of forest conversion to oil palm plantations are more severe.

Responses of Soil Fungi to Logging and Oil Palm Agriculture in Southeast Asian Tropical Forests

“…Our results also imply that fungi may be more sensitive to logging than soil bacterial communities, as a recent study found that bacterial communities were compositionally distinct in oil palm soils, but were not different between primary and logged forests [44]. The differences in soil physical and chemical properties across land-use types likely explains some of the differences we observed [51], although further analysis and experimentation will be necessary, as differences in fungal composition across sites are likely due to a combination of other biotic and abiotic factors that have not yet been measured.…”

“…Palm oil, the commercial commodity extracted from oil palm fruits and kernels, is currently the most lucrative vegetable oil crop in the world, and Indonesia and Malaysia alone account for more than 80 % of all palm oil production [40,43]. To date, only a single culture-independent study has been conducted in oil palm agricultural soils in Malaysia, which found that bacterial communities were dramatically different in these ecosystems relative to primary and logged forests [44]. While there have been some small-scale studies examining the diversity of fungi in oil palm plantations [45,46], these have mostly focused on decomposer fungi and no molecular studies have evaluated soil fungal communities in these agricultural landscapes.…”

Land use not litter quality is a stronger driver of decomposition in hyperdiverse tropical forest

“…In spite of noticeable tree removal due to selective logging and a modified tree composition resulting in abundant pioneer species (S. Both, unpublished data), our study revealed that the soil chemical and microbial properties were remarkably similar in both land‐use types. The soil microbial communities under tropical forests can be resilient to disturbance from logging (Lee‐Cruz, Edwards, Tripathi, & Adams, 2013; Tripathi et al., 2016), which may apply to our study system. However, despite similar free‐living microbial community composition, differences in the rate of loss of nutrients from litter suggest functional differentiation between communities.…”

Assessment of the Influence of Oil Palm and Rubber Plantations in Tropical Peat Swamp Soils Using Microbial Diversity and Activity Analysis

“…The results showed that bacterial community diversity was most affected by agricultural practices (only 30% similarity compared with the microbial community present in the NF soil sample). Previously, it has been reported that there were greater shifts in the bacterial community in response to the conversion of tropical forest soils to oil palm plantations than logging activities [51] as well as long term fertilizer amendments [52]. The microbial diversity of the RP soil sample was significantly different (41% different from fungal community and 50% different from Archaeal community) and occurred in a different cluster in PCA analysis compared with NF (Figure 3).…”