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Abstract Global changes such as nitrogen (N) enrichment and elevated carbon dioxide (CO2) are known to exacerbate biodiversity loss in grassland ecosystems. They do so by modifying processes whose strength may vary at different spatial scales. Yet, whether and how global changes impact plant diversity at different spatial scales remains elusive.We collected data on species presence and cover at a high resolution in the third decade of a long‐term temperate grassland biodiversity—global change experiment. Based on the data, we constructed species—area relationships across three spatial orders of magnitude (from 0.01 to 3.24 m2) and compared them for the different global change treatments.We found that N enrichment, both under ambient and elevated CO2levels, decreased species richness across almost all spatial scales, with proportional decreases being largest at the smallest spatial scales. Elevated CO2also reduced richness at both ambient and enriched N supply rates but did so proportionally across all spatial scales. Suppression of diversity was stronger at all scales for diversity indices that include relative abundances than for species richness. Taken together, these results suggest that CO2and N are re‐organizing this grassland system by increasingly favouring, at fine scales, a small subset of dominant species.Synthesis: Our results highlight the role of spatial scales in influencing biodiversity loss, especially when it is driven by anthropogenic resource changes that might influence species interactions differently across spatial scales.
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This content will become publicly available on July 1, 2026
TinyCO2: High‐performance, low‐cost CO2 enrichment for field‐grown plants
Abstract Rising atmospheric CO2levels place terrestrial ecosystems under novel environmental conditions, and research in field settings is key to understanding how real plant communities will respond. Despite decades of progress in elevated CO2(eCO2) experiments, major gaps persist in our knowledge of plant responses to interacting influences of climate change, especially in areas outside North America and Western Europe.With a goal to expand access to field‐based eCO2research, we designed, built, and tested TinyCO2, a low‐cost field experiment for climate change research on plants. TinyCO2features sixteen 0.62‐m2plot areas, half with ambient and half with elevated (+200 ppm) CO2concentrations, and is suitable for short‐stature plants (≤0.5 m in height).Using a proportional‐integral control algorithm and constant sampling of air within the plots, TinyCO2achieves consistent elevation of [CO2] averaging +196.9 ppm. During testing, 95.1% of measured CO2concentrations fell within 20% of the setpoint (ambient CO2 + 200 ppm). A streamlined design and efficient use of instrumentation reduced the cost of the system to roughly one‐fifth of the cost of similar experiments from the past 30 years ($13.68 vs. $64.65 ppm−1 m−2, adjusted to 2024 USD).Our results demonstrate a system capable of precise and accurate field‐based CO2elevation for significantly reduced cost. We envision the TinyCO2design being implemented in a multitude of field‐based eCO2studies, perhaps as part of a globally distributed collaborative network experiment.
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- Award ID(s):
- 2307341
- PAR ID:
- 10617625
- Publisher / Repository:
- Methods in Ecology and Evolution
- Date Published:
- Journal Name:
- Methods in Ecology and Evolution
- Volume:
- 16
- Issue:
- 7
- ISSN:
- 2041-210X
- Page Range / eLocation ID:
- 1389 to 1396
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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