Biology subjects

Dukes, J. S.

Publications and source records attributed to Dukes, J. S..

3 recordsLinked to original sources

bioRxiv2026

The PSInet Plant Water Potential Database: advancing new perspectives on plant water status, traits, and hydraulic processes

Water potential gradients drive water flow within and between soils and plants, and the internal plant water potential controls a wide range of physiological processes including photosynthesis, growth, and mortality. Notwithstanding this clear relevance for many critical aspects of ecosystem function, water potential data have historically been relatively inaccessible and unnetworked. The absence of a centralized repository for plant water potential time series limits our ability to integrate a wealth of ecophysiological information from other networks and from remote sensing. Closing this gap is necessary to address unresolved questions about plant responses to drought and heat stress, and to make confident predictions about plant and ecosystem function in a warming world. Here, we introduce the PSInet database -- a global collection of plant water potential time series from 285 datasets representing 523 species. We present the workflow that guided database development and evaluate its key features. Through a series of preliminary analyses, we then highlight the potential of the PSInet database for applications including: a) advancing plant water use strategy frameworks; b) disentangling the impacts of soil versus atmospheric drought stress; c) assessing the long-held assumption of pre-dawn equilibration of ecosystem water potential; d) understanding the risk of drought-driven mortality; and e) benchmarking remote-sensing data products and land-surface models.

plant biology↗

bioRxiv2026

Warming and precipitation change alter flowering phenology and coflowering networks in California serpentine grasslands

Coflowering, the temporal overlap in flowering among plant species, can influence plant fitness through its effects on heterospecific pollen transfer and competition for pollinators and resources. This temporal overlap is changing as plant species respond differently to climate change. However, difficulties in quantifying and comparing patterns of coflowering across diverse, multispecies communities have limited progress in understanding climate-driven shifts in coflowering. Network-based approaches offer a promising solution to this limitation. Here, we investigate how warming and altered precipitation influence coflowering network structure, flowering phenology, and seed production in 12 annual California serpentine grassland plant species in a mesocosm experiment, using coflowering network analysis and structural equation modeling. Communities consistently grouped into two phenological modules corresponding to early- and late-season annuals. Warming reduced the overall amount of coflowering in the community, driven primarily by weakened and less diverse coflowering among late-season species. Soil moisture moderated these effects: late-season coflowering was strongest under cool-wet conditions and weakest under warm conditions regardless of soil moisture. In contrast, early-season species had a more fixed phenological window, and maintained stable coflowering relationships across climates. Growth form (grass or forb) and origin (native vs. non-native) did not predict coflowering responses. We additionally found that temperature and soil moisture influenced seed production largely through their effects on flowering phenology, with early- and late-season species exhibiting distinct phenological responses and sensitivities. Our results demonstrate that warming and precipitation change can spread out flowering times within functional groups, reshaping community-wide coflowering networks through species-specific responses to altered climate conditions.

ecology↗

bioRxiv2018

Microbial dormancy improves predictability of soil respiration at the seasonal time scale

Climate change is accelerating global soil respiration, which could in turn accelerate climate change. The biological mechanisms through which soil carbon (C) responds to climate are not well understood, limiting our ability to predict future global soil respiration rates. As part of a climate manipulation experiment, we tested whether differences in soil heterotrophic respiration driven by season or climate treatment (RH) are linked to 1) relative abundances of microbes in active and dormant metabolic states, 2) net changes in microbial biomass and/or 3) changes in the relative abundances of microbial groups with different C-use strategies. We used a flow-cytometric single-cell metabolic assay to quantify the abundance of active and dormant microbes, and the phospholipid fatty acid (PLFA) method to determine microbial biomass and ratios of fungi:bacteria and Gram-positive:Gram-negative bacteria. RH did not respond to climate treatments but was greater in the warm and dry summer than in the cool and less-dry fall. These dynamics were better explained when microbial data were taken into account compared to when only physical data (temperature and moisture) were used. Overall, our results suggest that RH responses to temperature are stronger when soil contains more active microbes, and that seasonal patterns of RH can be better explained by shifts in microbial activity than by shifts in the relative abundances of fungi and Gram-positive and Gram-negative bacteria. These findings contribute to our understanding of how and under which conditions microbes influence soil C responses to climate.

microbiology↗