Consequences of tropical forest conversion to oil palm on soil bacterial community and network structure

Abstract

Tropical forest conversion to agriculture is a major global change process. Understanding of the ecological consequences of this conversion are limited by poor knowledge of how soil microorganisms respond. We analyzed the response of soil bacteria to conversion from primary rain forest to oil palm plantation and regenerating logged forest in Malaysia. Bacterial diversity increased by approximately 20% with conversion to oil palm because of higher pH due to liming by plantation managers. Phylogenetic clustering indicated that bacterial communities were determined by environmental filtering. Regenerating logged forests did not have significantly different soil chemistry, which did not correspond with significant differences in bacterial richness, diversity, or the relative abundances of particular taxa. However, there were significant differences in the structure of bacterial community networks between regenerating logged forests and primary forests, highlighting previously unobserved effects of these two land uses. Network analysis highlighted taxa that are potentially central to bacterial networks, but have low relative abundances, suggesting that these rare taxa could play an ecological role and therefore warrant further research.

Contrasting Patterns of the Bacterial Communities in Melting Ponds and Periglacial Rivers of the Zhuxi glacier in the Tibet Plateau

“…In our present study, co-occurrence networks in melt ponds and periglacial rivers suggested that most of the involved nodes belonged to the rare sub-communities. This pattern has previously been reported from other glacial environments in Tibet Plateau [23] and from other habitats, such as soil [58,59], rivers [60], and oceans [61]. Moreover, the over-proportional roles of rare taxa were also shown by our finding that all 7 keystones in melt ponds and 11 out of 12 keystones in periglacial rivers were affiliated with rare OTUs.…”

“…Based on the increasing nutrient resource from melt ponds to periglacial rivers, a niche difference is expected, which allows the bacterial communities to adapt quickly to available nutrients without the need to establish interactions with neighboring microorganisms [68]. As a consequence, the higher connectivity of bacterial communities in melt ponds would result in greater vulnerability to disturbance because the whole community will be more affected by the other nodes [58]. In contrast, we found that the network in melt ponds had significantly shorter average path length than did that of the periglacial rivers.…”

Fertilization shapes a well-organized community of bacterial decomposers for accelerated paddy straw degradation

“…Changes in transitivity, average harmonic geodesic distances and geodesic efficiencies also support the above scenario. Lower transitivity indicates weaker interactions and couplings within the community 52 , hence stronger stability of the co-occurrence network is achieved 53 . The smaller average harmonic geodesic distances and the larger geodesic efficiencies of the Control network indicate that all nodes are closer 54 , 55 and fertilization decreases the interspecies collaboration.…”

Using GIS and Artificial Neural Network for Deforestation Prediction

“…Simulation of land cover and land use change plays a crucial role in management natural resources as well as in academic research. In deforestation, the development of models is accomplished by several useful factors [24], [25], [26]: Providing a better understanding of how deforestation factors play a role Production of a future scenario for deforestation Forecast of forest destruction In order to support the design of responsible forestry policy The purpose of this study is to develop a simple spatial model that can predict deforestation using artificial neural networks [27], [28], [29].…”