ORCID Profile
0000-0002-4766-9399
Current Organisation
Virginia Tech
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Publisher: Springer Science and Business Media LLC
Date: 18-09-2020
DOI: 10.1038/S41467-020-18451-3
Abstract: The importance of soil age as an ecosystem driver across biomes remains largely unresolved. By combining a cross-biome global field survey, including data for 32 soil, plant, and microbial properties in 16 soil chronosequences, with a global meta-analysis, we show that soil age is a significant ecosystem driver, but only accounts for a relatively small proportion of the cross-biome variation in multiple ecosystem properties. Parent material, climate, vegetation and topography predict, collectively, 24 times more variation in ecosystem properties than soil age alone. Soil age is an important local-scale ecosystem driver however, environmental context, rather than soil age, determines the rates and trajectories of ecosystem development in structure and function across biomes. Our work provides insights into the natural history of terrestrial ecosystems. We propose that, regardless of soil age, changes in the environmental context, such as those associated with global climatic and land-use changes, will have important long-term impacts on the structure and function of terrestrial ecosystems across biomes.
Publisher: Proceedings of the National Academy of Sciences
Date: 15-03-2019
Abstract: Belowground organisms play critical roles in maintaining multiple ecosystem processes, including plant productivity, decomposition, and nutrient cycling. Despite their importance, however, we have a limited understanding of how and why belowground bio ersity (bacteria, fungi, protists, and invertebrates) may change as soils develop over centuries to millennia (pedogenesis). Moreover, it is unclear whether belowground bio ersity changes during pedogenesis are similar to the patterns observed for aboveground plant ersity. Here we evaluated the roles of resource availability, nutrient stoichiometry, and soil abiotic factors in driving belowground bio ersity across 16 soil chronosequences (from centuries to millennia) spanning a wide range of globally distributed ecosystem types. Changes in belowground bio ersity during pedogenesis followed two main patterns. In lower-productivity ecosystems (i.e., drier and colder), increases in belowground bio ersity tracked increases in plant cover. In more productive ecosystems (i.e., wetter and warmer), increased acidification during pedogenesis was associated with declines in belowground bio ersity. Changes in the ersity of bacteria, fungi, protists, and invertebrates with pedogenesis were strongly and positively correlated worldwide, highlighting that belowground bio ersity shares similar ecological drivers as soils and ecosystems develop. In general, temporal changes in aboveground plant ersity and belowground bio ersity were not correlated, challenging the common perception that belowground bio ersity should follow similar patterns to those of plant ersity during ecosystem development. Taken together, our findings provide evidence that ecological patterns in belowground bio ersity are predictable across major globally distributed ecosystem types and suggest that shifts in plant cover and soil acidification during ecosystem development are associated with changes in belowground bio ersity over centuries to millennia.
Publisher: Springer Science and Business Media LLC
Date: 02-08-2019
DOI: 10.1038/S41467-019-11472-7
Abstract: Identifying the global drivers of soil priming is essential to understanding C cycling in terrestrial ecosystems. We conducted a survey of soils across 86 globally-distributed locations, spanning a wide range of climates, biotic communities, and soil conditions, and evaluated the apparent soil priming effect using 13 C-glucose labeling. Here we show that the magnitude of the positive apparent priming effect (increase in CO 2 release through accelerated microbial biomass turnover) was negatively associated with SOC content and microbial respiration rates. Our statistical modeling suggests that apparent priming effects tend to be negative in more mesic sites associated with higher SOC contents. In contrast, a single-input of labile C causes positive apparent priming effects in more arid locations with low SOC contents. Our results provide solid evidence that SOC content plays a critical role in regulating apparent priming effects, with important implications for the improvement of C cycling models under global change scenarios.
No related grants have been discovered for Mark A. Williams.