Leaf-Associated Shifts in Bacterial and Fungal Communities in Response to Chicken Rearing Under Moso Bamboo Forests in Subtropical China

The Potential of Understory Production Systems to Improve Laying Hen Welfare

The welfare of laying hens in cage systems is of increasing concern. Represented by the European Union's 'End the Cage Age' initiative, more and more countries have advocated cage-free farming. China, an important country for poultry farming and consumption in the world, is highly dependent on cage systems and lacks confidence in alternative (e.g., free-range) systems. In this context, using China's abundant woodland resources (including natural forests, plantations, and commercial forests) to facilitate the management of laying hens in a free-range environment may provide highly promising welfare improvement programs. On the basis of the Five Freedoms, we assess the welfare status of understory laying hen management systems with reference to the behavioural needs and preferences of laying hens and the EU standards for free-range and organic production (highest animal welfare standards in the world). The results show that the considered systems meet or even exceed these standards, in terms of key indicators such as outdoor and indoor stocking density, outdoor activity time, and food and drug use. Specifically, the systems provide sufficient organic food for laying hens without using antibiotics. They allow laying hens to avoid beak trimming, as well as to express nesting, foraging, perching, reproductive, dustbathing and other priority behaviours. The presence of roosters and higher use of woodland space allow the laying hens to achieve better feather and bone conditions, thus reducing stress and fear damage. Notably, the predation problem is not yet considered significant. Second, there is evidence that understory laying hen systems are profitable and have been welcomed and supported by farmers and governments in the southwest, south, and north of China. However, whether it can be scaled up is uncertain, and further research is needed. In addition, laying hens in this management system face various risks, such as foot injury, parasitism, and high dependence on consumer markets, which must be considered. Overall, agro-forestry, or accurately, understory poultry raising, provides opportunities and possibilities for free-range laying hens and welfare improvement in China and other countries.

Fungal diversity within the phyllosphere of Pinus massoniana and the possible involvement of phyllospheric fungi in litter decomposition

Fungi play key roles in forest ecosystems and help to shape the forest's diverse functions. However, little is known about the diversity of phyllospheric fungi or their possible relationships with fungal communities residing in different micro-environments of Pinus massoniana forests. We investigated seven different sample types: mature needles (NM), dead needles (ND), needles falling as litter (L), fermenting needles (F), humus (H), top soil (0-20 cm) (TS), and secondary soil (20-40 cm) (SS). These seven fungal communities were examined and compared with ITS amplicons using a high-throughput sequencing technique. A total of 1213 fungal operational taxonomic units (OTUs) were obtained at a 97% sequence similarity level. Distinct fungal communities were associated with different sample types. A greater number of OTUs were present in both NM and F samples than those shared by both NM and TS samples, indicating that phyllospheric fungi may play crucial roles in litter decomposition. Sixty OTUs (the core microbiome) were found in all sample types, and they may probably play different ecological roles in different sample types. These findings extend our knowledge of the fungal diversity of the phyllosphere and its possible interactions with fungal communities found in distinct forest micro-habitats.

Responses of soil nutrients and microbial communities to intercropping medicinal plants in moso bamboo plantations in subtropical China

Bamboo forests are one of the most important forest resources in subtropical China. A pure, single-layer bamboo forest is considered an optimal habitat for intercropping medicinal herbs. Soil microorganisms have an important role in various ecological processes and respond quickly to environmental changes. However, changes in soil nutrients and microbial communities associated with agroforestry cultivation methods remain poorly documented. In the present study, a pure moso bamboo (Phyllostachys edulis) forest (Con) and three adjacent moso bamboo-based agroforestry (BAF) systems (moso bamboo-Paris polyphylla (BP), moso bamboo-Tetrastigma hemsleyanum (BT) and moso bamboo-Bletilla striata (BB)) were selected; and their soil chemical properties and bacterial communities were studied and compared to evaluate the effects of agroforestry on soil bacterial communities and the relationship between soil properties and bacterial communities in BAF systems. Results showed that compared with soils under the Con, soils under the BAF systems had more (p < 0.05) soil organic carbon (SOC) and available nitrogen (AN) but lower (p < 0.05) pH and available potassium (AK). In addition, compared with the Con system, the BB and BT systems had significantly greater (p < 0.05) available phosphorus (AP). Compared with that in the Con system, the Shannon index in the BAF systems was significantly greater (p < 0.05), but the Chao1 index not different. On the basis of relative abundance values, compared with the Con soils, the BAF soils had a significantly greater abundance of (p < 0.05) Bacteroidetes and Planctomyces but a significantly lower abundance of (p < 0.05) Verrucomicrobia, Gemmatimonadetes and Candidatus Xiphinematobacter. Moreover, compared with the Con system, the BB and BT systems had a greater (p < 0.05) abundance of Actinobacteria, Rhodoplanes, Candidatus Solibacter and Candidatus Koribacter. Redundancy analysis (RDA) revealed that soil pH, SOC and AP were significantly correlated with bacterial community composition. Results of this study suggest that intercropping medicinal herbs can result in soil acidification and potassium (K) depletion; thus, countermeasures such as applications of K fertilizer and alkaline soil amendments are necessary for BAF systems.

Changes of Root Endophytic Bacterial Community Along a Chronosequence of Intensively Managed Lei Bamboo (Phyllostachys praecox) Forests in Subtropical China

Endophytic bacteria widely exist inside plant tissues and have an important role in plant growth and development and the alleviation of environmental stress. However, little is known about the response of root-associated bacterial endophytes of Lei bamboo (Phyllostachys praecox) to intensive management, which is a common management practice for high bamboo shoot production in subtropical China. In this study, we comparatively investigated the root endophytic bacterial community structures in a chronosequence of intensively managed (5a, 10a, 15a, and 20a) and extensively managed plantations (as control, Con). The results showed that endophytic Proteobacteria was the dominant bacterial phylum in the bamboo roots. Intensive management significantly increased (p < 0.05) the bacterial observed species and Chao1 (except 5a) indices associated with bamboo roots. The relative abundances of Firmicutes, Bacteroidetes, and Actinobacteria (except 15a) in the intensively managed bamboo roots significantly increased (p < 0.05) compared with those in Con, while the relative abundance of Proteobacteria significantly decreased in intensively managed bamboo roots (p < 0.05). The phyla Proteobacteria, Actinobacteria, Bacteroidetes, and Firmicutes were the biomarkers in Con, 5a, 15a, and 20a, respectively. Redundancy analysis (RDA) showed that soil alkali-hydrolysable N (AN), available phosphorus (AP), available K (AK), and total organic carbon (TOC) were significantly correlated (p < 0.05) with the bacterial community compositions. Our results suggest that the root endophytic microbiome of Lei bamboo was markedly influenced by intensive management practices, and the available nutrient status could be the main driving factor for such shifts. Although heavy fertilization in the intensive management system increased the diversity indices, the rapid changes in root endophyte communities and their relevant functions might indicate a high risk for sustainable management.