Biology subjects

Tseng, Y.-P.

Publications and source records attributed to Tseng, Y.-P..

3 recordsLinked to original sources

bioRxiv2026

Metabolic switching promotes microbial coexistence under fluctuating resources

Resource fluctuations can facilitate microbial coexistence when species are sufficiently differentiated in their resource uptake strategies. However, past emphasis on the binary classification of species into equilibrium versus non-equilibrium resource specialists has obscured the potential range of temporal niches available to competitors. Here, we investigate whether microbes that switch between respiratory and fermentative metabolism can coexist with specialist competitors under fluctuations in a single resource. Based on simulations of consumer-resource models, we show that metabolic switching generates distinct growth responses to resource availability, allowing metabolically flexible organisms to exploit temporal variation in ways that differ from specialist strategies. As a result, metabolic switchers can coexist with both respiratory and fermentative specialists under intermediate regimes of resource fluctuation. The competitive ability of metabolic switchers is enhanced when transitions between metabolic states are faster and more responsive to changes in resource availability. Rather than constituting physiological constraints, our results suggest that the metabolic flexibility afforded by overflow metabolism may enable organisms to better exploit fluctuating resources environments.

ecology↗

bioRxiv2026

Extending island biogeography theory to biotic islands: Microbial communities in epiphytic bird's nest fern Asplenium nidus

1. Biotic insular systems differ from conventional islands because patch attributes change dynamically as patch-forming organisms develop. It therefore remains unclear whether the assembly mechanisms predicted by island biogeography theory (IBT) operate in such systems. Here, using epiphytic birds nest ferns (BNFs, Asplenium nidus) as a model biotic island system, we tested whether fungal and bacterial community diversity conform to species-area relationships predicted by IBT. With a stratified sampling scheme, we further evaluated the underlying mechanisms (passive sampling, disproportionate effects, and environmental heterogeneity) of species-area relationships, and assessed isolation effects using distance-decay patterns in community similarity. 2. We treated each BNF individual as a microbial island and categorized 24 BNFs into three size classes. Microbial and humus samples from multiple litter layers within each BNF individual were collected; microbial communities were characterized using next-generation sequencing, and humus chemical properties (pH and C:N ratio) were measured to characterize microhabitat conditions. To investigate mechanisms underlying species-area relationships, we applied a multi-scale rarefaction framework to partition diversity components. Spatial distances among BNFs were quantified to evaluate isolation effects. 3. Consistent with IBT predictions, both fungal and bacterial communities exhibited positive species-area relationships, indicating that larger BNFs harbored greater microbial richness. Diversity partitioning suggested that fungal richness increased through both disproportionate effects and environmental heterogeneity, whereas bacterial richness was primarily driven by environmental heterogeneity. Within larger ferns, greater heterogeneity in litter pH was associated with increased species turnover across litter layers, suggesting that decomposition-driven pH gradients create diverse microhabitats that promote microbial diversity. In addition, both microbial communities exhibited distance-decay patterns, indicating that isolation contributes to community assembly through dispersal limitation. 4. Synthesis. Our results demonstrate that BNFs function as a biotic insular system, in which both patch size and spatial isolation structure microbial diversity, consistent with predictions from IBT. Furthermore, we show that environmental heterogeneity generated by the growth of the habitatforming BNF mechanistically links island area to microbial diversity. Our study integrates both local habitat heterogeneity and regional spatial structure, highlighting the potential to extend IBT and metacommunity theory to organism-formed habitats.

ecology↗

bioRxiv2023

The ecological characteristics of the safe sites for early-stage establishment of Chamaecyparis obtusa var. formosana seedlings in Taiwan

Chamaecyparis obtusa var. formosana is an ecologically and economically important species in Taiwan, with a high affinity for fog immersion. Our study aims to identify possible stress factors that induced seedling mortality and investigate how different ecological factors influence early-stage safe site requirements of the seedlings. We focused on the effect of large-scale climatic variables, small-scale microhabitat conditions, and biotic interactions on seedling survival and establishment by applying seasonal seedling survival monitoring and establishment survey on both regional and local scale. We identified two alternative ways of seedling death, by environmental-induced mortality and by herbivory. Opposite effects of the same environmental factors on different causes of mortality showed that seedlings might need to balance the risks posed by both causes to optimize their growing conditions. On a regional scale, we observed limited effect of regional climatic variables (namely fog frequency) on seedlings establishment and survival but noted a similar seasonal survival pattern among regions. We hypothesize that short-duration droughts during the transition from Plum rain to typhoon season is one of the key mechanisms of environmental-induced mortality. On a local scale, we found that decayed coarse wood debris (CWD) facilitates seedling establishment by providing a "safe site", likely due to increased colonization of small-stature bryophytes and decreased litterfall accumulation. The effect of bryophytes on seedling establishment varies depending on their thickness, with thicker ones having stronger negative effects. Aside from the bryophytes, the accumulation of litter significantly hindered seedling establishment. We argue that to safeguard the regeneration of Chamaecyparis obtusa var. formosana population, preserving CWD in the forest floor as a safe site for the seedlings after tree-replacing disturbance in natural forests is essential, particularly under ongoing climate change where more frequent and prolonged drought events are predicted. HighlightsO_LIOn a local scale, decayed coarse wood debris (CWD) provides "safe site" for the establishment of Chamaecypairs obtusa var. formosana seedlings. C_LIO_LIRegional climatic variables had limited effects on seedlings, but all regions had similar seasonal patterns of seedling mortatlity. C_LIO_LIFacilitation effect of small-stature bryophytes and litterfall avoidance might be the underlying mechanisms behind CWD safe sites. C_LIO_LIPreserving CWD for seedlings is important in the context of predicted prolong drought events under ongoing climate change. C_LI

ecology↗